Powering Freight & Transportation - Power Systems Design
Powering Freight & Transportation - Power Systems Design
Powering Freight & Transportation - Power Systems Design
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E m p o w e r i n g G l o b a l I n n o v a t i o n O c t o b e r 2 0 0 8<br />
Special Report – <strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
<strong>Design</strong> Tips<br />
<strong>Design</strong> Tips<br />
ISSN: 1613-6365
Ultra-Low <strong>Power</strong> LDOs<br />
150mA, 500nA I Q Regulators for MCU-Based Applications<br />
Applications<br />
– TI MSP430-based applications<br />
and other microcontrollers<br />
– <strong>Power</strong> rails with programming<br />
mode<br />
– Wireless handsets and other<br />
low-power, battery-powered<br />
products<br />
Features<br />
– Low I Q : 500nA (typ)<br />
– Available in fixed output<br />
voltages from 1.5V to 4.2V using<br />
innovative factory EPROM<br />
programming<br />
– Available in adjustable versions<br />
from 1.22V to 5.25V<br />
– V SET pin toggles output voltage<br />
between two factory-programmed<br />
voltage levels<br />
– Stable with a 1.0µF ceramic<br />
capacitor<br />
– Logic level compatible enable pin<br />
– Price: $0.65 (1k)<br />
<strong>Power</strong><br />
Management<br />
TPS780xx<br />
2mm x 2mm<br />
150mA<br />
High-Performance Analog >>Your Way and the platform bar are trademarks of Texas Instruments. 2252A1 © 2008TI<br />
GND<br />
High-Performance Analog>>Your Way<br />
V CC<br />
I/O<br />
Microcontroller<br />
GND<br />
TI’s TPS780xx LDOs with dual-level voltage output for low-power,<br />
battery-powered devices consume only 500nA of quiescent current.<br />
The LDOs implement dynamic voltage scaling (DVS), using a voltage<br />
select (V SET ) pin to allow switching between two voltage levels to<br />
customize and cut power consumption.<br />
Device<br />
VIN (V)<br />
IOUT (mA)<br />
VOUT (V)<br />
IQ (µA) Package<br />
Price<br />
(1k)*<br />
TPS780xx 2.2 - 5.5 150 1.22 - 5.25 500nA TSOT-23, SON $0.65<br />
TPS781xx 2.2 - 5.5 150 1.22 - 5.25 1 TSOT-23, SON $0.50<br />
TPS797xx 1.8 - 5.5 10 1.25 - 4.9 1.2 SC70 $0.34<br />
TPS715xx 2.5 - 24 50 1.2 - 15 3.2 SC70 $0.34<br />
TPS715Axx 2.5 - 24 80 1.2 - 15 3.2 SON $0.44<br />
* Suggested resale price in U.S. dollars in quantities of 1,000.<br />
Visit us at electronica Booth A4.420<br />
www.ti.com/tps780xx-e or call toll free:<br />
00800-ASKTEXAS (00800 275 83927)<br />
or international: +49 (0) 8161 80 2121<br />
Get Evaluation Modules, Samples and <strong>Power</strong> Management Selection Guide<br />
Dilbert – 72<br />
Viewpoint<br />
Engineering Rules – OK? ...........................................................................................................................................................................................4<br />
Industry News<br />
Digi-Key Corporation and Alpha & Omega Semiconductor Sign Global Distribution Agreement ............................................................................6<br />
Vicor Strengthens European Team ............................................................................................................................................................................6<br />
SolFocus Completes CPV Installation at ISFOC’s 3MW Solar <strong>Power</strong> Plant .............................................................................................................6<br />
General Manager Boosts Management Team at Gresham .......................................................................................................................................8<br />
High-Performance Two-Wheel Inverted Pendulum Robot via R&D Cooperation .....................................................................................................8<br />
LTi REEnergy Selects Maxwell Technology BOOSTCAP ® Ultracapacitors for Backup <strong>Power</strong> in Wind Turbines ....................................................10<br />
Microsemi Appoints Bel Lazar Senior VP of Operations .........................................................................................................................................12<br />
TTI Signs Pan-European Franchise Deal with C&K Components ...........................................................................................................................12<br />
Lineage <strong>Power</strong> Appoints Global VP of OEM Sales .................................................................................................................................................12<br />
<strong>Power</strong> Events.................................................................................................................................................................................................12<br />
Energy-Efficient Chokes for <strong>Transportation</strong> ............................................................................................................................................................14<br />
Optimized <strong>Power</strong> Processing and Energy Efficiency, By Oleg Khaykin, International Rectifier ..............................................................................16<br />
Portable <strong>Power</strong>-Management Market Throws the Switch, By Marijana Vukicevic, iSuppi .....................................................................................18<br />
<strong>Design</strong> Tips<br />
<strong>Power</strong> Supply Control <strong>Design</strong> Tools – Part VI, By Dr. Ray Ridley, Ridley Engineering ............................................................................................20<br />
On The Road<br />
Fairchild Semiconductor, Texas Instruments, Sharp Microelectronics, Linear Technology, Vicor/Picor, Reported by Cliff Keys, Editor-in-Chief, PSDE .....24<br />
Cover Story<br />
On The Right Track, By Michel Ghilardi & Marc Schaerrer, LEM SA .......................................................................................................................31<br />
Solar <strong>Power</strong><br />
Solar <strong>Power</strong> Shines! Part II, By Alfred Hesener, Fairchild Semiconductor ..............................................................................................................37<br />
Lighting<br />
Avoiding Current Spikes with LEDs, By Pat Goodman, Philips Lumileds ...............................................................................................................41<br />
Special Report: <strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
Transport and Automotive Appliances Benefit from Multiphase Boosters, By Bruce Haug & Tick Houk, Linear Technology ...............................46<br />
Electric Vehicle Battery Monitoring, By Warren Pettigrew, Raztec Sensors............................................................................................................52<br />
Circuit Protection for Safer Automotive Electrical Architectures, By Guillemette Paour, Tyco Electronics .............................................................55<br />
One Step Closer to the Birds, By Marco Panizza, Vicro Europe .............................................................................................................................58<br />
Progressing <strong>Freight</strong> and <strong>Transportation</strong>, By Sven Baechtiger, Maxwell Technologies............................................................................................61<br />
New Products.................................................................................................................................................................................................64<br />
Whichever Way the Wind Blows, Reported by Cliff Keys, Editor-in-Chief, PSDE ...................................................................................................72<br />
Member<br />
Arnold Alderman<br />
Heinz Rüedi<br />
Marion Limmer<br />
Dr. Reinhold Bayerer<br />
Dr. Leo Lorenz<br />
Davin Lee<br />
Eric Lidow<br />
Tony Armstrong<br />
Hans D. Huber<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> Europe Steering Committee Members<br />
Representing<br />
Anagenesis<br />
CT-Concept Technology<br />
Fairchild Semiconductor<br />
Infineon Technologies<br />
Infineon Technologies<br />
Intersil<br />
International Rectifier<br />
Linear Technology<br />
LEM<br />
Member<br />
Andrew Cowell<br />
Michele Sclocchi<br />
Kirk Schwiebert<br />
Christophe Basso<br />
Balu Balakrishnan<br />
Paul Greenland<br />
Uwe Mengelkamp<br />
Peter Sontheimer<br />
Representing<br />
Micrel<br />
National Semiconductor<br />
Ohmite<br />
On Semiconductor<br />
<strong>Power</strong> Integrations<br />
Semtech<br />
Texas Instruments<br />
Tyco Electronics
VIEWPOINT<br />
Engineering Rules – OK?<br />
In this issue we have brought<br />
together the rather adventurous<br />
theme of ‘<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> and<br />
<strong>Transportation</strong>’. With the proliferation<br />
of power electronics in traction, mobility<br />
and freight, we thought we’d look at<br />
the relatively unexplored area of our<br />
technology. The feature includes the<br />
power and control of systems which give<br />
mobility to freight, goods and people, in<br />
fact anywhere where electronics is used<br />
to make our everyday lives easier; from<br />
the supermarket bands that transport<br />
our shopping at the checkout, on<br />
through escalators, golf carts, disabled<br />
vehicles, stair-lifts and of course electric<br />
locomotives. A huge power saving<br />
opportunity! I find it really exciting that<br />
when we take off the blinkers from our<br />
individual ‘comfort zones’, we find that<br />
our world of power and its conservation<br />
is to be found everywhere.<br />
Britain languishes near the bottom<br />
of the European renewables league<br />
table which is a very sad state of affairs.<br />
The International Energy Agency<br />
said Britain’s renewables strategy is<br />
“ineffective” and “very expensive”. The<br />
agency’s new report ranks Britain 31st<br />
out of 35 countries - “including all the<br />
major industrial nations such as the<br />
US, Germany and China” - in its green<br />
energy cost league with ‘renewables<br />
effectiveness’ a ridiculous 3%. The<br />
government seems to favour nuclear<br />
and coal, rather than to take a more<br />
environmentally-sensible approach.<br />
Several European countries are now<br />
giving priority access to the grid for low<br />
carbon generated energy, but in the UK<br />
at times there are reports of situation<br />
where fully working wind farms are<br />
turned off because a fossil fuel plant has<br />
priority access to the grid. When can we<br />
get a European government policy that<br />
makes good sense for the population<br />
and the environment rather than<br />
watered-down policies which look to be<br />
an unhealthy compromise to satisfy the<br />
powerful career-politicians and influential<br />
business leaders?<br />
A piece of breaking news for our<br />
colleagues in North America: <strong>Power</strong><br />
<strong>Systems</strong> <strong>Design</strong> has just announced the<br />
launch of its North American magazine,<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> North America,<br />
which is due to hit the streets in the<br />
January/February issue timeframe. I will<br />
be the editor for the magazine and look<br />
forward to also serving our colleagues<br />
in the US. Naturally I’ll try to get the best<br />
reports of both regions to our expanded<br />
power community.<br />
I am in the midst of my US visit to<br />
see the major players here and to gain<br />
for our readers an insight into what’s<br />
happening here and what’s ‘in the pipe’<br />
preparing for launch.<br />
We soon have the gruesome-but-fun<br />
experience of electronica. Many of us<br />
are finalizing last-minute presentations,<br />
product demos or trade stands for this<br />
huge event, one of the biggest and most<br />
comprehensive electronics shows in the<br />
world. With an expected visitor profile<br />
of 80,000+, we should all be kept pretty<br />
busy. As always I’ll pull together an<br />
overview of what I see there for those of<br />
you who are too busy to come.<br />
Finally, I’d like to thank you for your<br />
continued support, healthy feedback and<br />
the all-important design features and<br />
articles that make our magazine a living<br />
proof that the power industry is a vibrant<br />
and growing community, of which we<br />
should all be rightly proud. Check out the<br />
Dilbert fun-strip on the GreenPage. Only<br />
our engineers will save the environment.<br />
All the best!<br />
Editor-in-Chief, PSDE<br />
Cliff.Keys@powersystemsdesign.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
INDUSTRY NEWS<br />
Digi-Key Corporation and Alpha & Omega<br />
Semiconductor Sign Global Distribution Agreement<br />
Digi-Key Corporation and Alpha & Omega<br />
Semiconductor, Inc. (AOS) have announced<br />
that the companies have signed a global<br />
distribution agreement.<br />
AOS is a leading developer of advanced<br />
semiconductor solutions. AOS products<br />
stocked by Digi-Key are featured in its print<br />
and online catalogs and are available for<br />
purchase directly from Digi-Key. This new<br />
distribution agreement will enable Digi-Key to<br />
fulfill both the design and production quantity<br />
needs of its very diverse customer base.<br />
“We are very excited to expand our<br />
semiconductor portfolio with products from<br />
Alpha & Omega Semiconductor,” said Mark<br />
Larson, Digi-Key president and COO. “AOS’<br />
commitment to excellence in design, manufacturing<br />
reliability, and responsiveness to<br />
its customers makes this company a good<br />
match for Digi-Key, and we are certain that<br />
AOS products will be of consequential interest<br />
and appeal to our customers.”<br />
“AOS and Digi-Key complement each<br />
other in its business philosophy of bringing<br />
Vicor Strengthens European Team<br />
Hannes Schachenmayer Catalin Tachiciu<br />
Vicor is investing in its European sales organisation<br />
and announces the appointment of<br />
Catalin Tachiciu as Regional Sales Manager<br />
SolFocus and ISFOC today announced<br />
the completion of SolFocus’ concentrator PV<br />
(CPV) installation in Spain at the Institute of<br />
Concentration Photovoltaic <strong>Systems</strong> (ISFOC)<br />
Germany, Switzerland and Denmark and<br />
Hannes Schachenmayr to Regional Sales<br />
Manager Eastern Europe.<br />
3MW municipal power production facility.<br />
SolFocus is the first of three companies to<br />
complete its contract with ISFOC in the first<br />
phase of the project. SolFocus has installed<br />
two distinct CPV power plants: 200kW at<br />
Puertollano and 300kW at Almoguera. The<br />
ISFOC facility has performed initial testing and<br />
analysis confirming that in SolFocus’ first commercial<br />
deployment of its flagship product, the<br />
SF-1000P CPV panel, each panel is performing<br />
as designed at specified power levels.<br />
The ISFOC project was created both as a<br />
municipal power plant and a proving ground<br />
for CPV technology. The original contract was<br />
awarded to SolFocus in late 2006, shortly<br />
after the creation of ISFOC as a power-pro-<br />
the best value to customers and best service<br />
in the industry. With Digi-Key’s global<br />
presence and top-rated online commerce,<br />
customers will be able to access AOS’ wide<br />
range of pr oducts in a more efficient manner,”<br />
said Jonus Chen, vice president of<br />
worldwide sales for AOS. “We look forward<br />
to a successful partnership with Digi-Key.”<br />
www.digikey.com<br />
www.aosmd.com<br />
Hannes Schachenmayer has created a<br />
strong distributor network and successfully<br />
developed the customer base in these markets<br />
for Vicor over the past 14 years. He has<br />
over 20 years’ experience in the power supply<br />
business and will now focus his expertise on<br />
building the Eastern European market for<br />
Vicor, which is an important and growing part<br />
of Vicor’s international business.<br />
Catalin Tachiciu, 45, who joins Vicor from<br />
Rohm Semiconductor, brings extensive experience<br />
with him. He graduated from Munich<br />
University with a degree in electronics and<br />
telecommunications and started his professional<br />
career in the semiconductor industry<br />
with Analog Devices and brings a strong<br />
sales and marketing focus in established and<br />
emerging markets.<br />
“We are excited about the addition of<br />
Catalin to the Vicor Team and it confirms<br />
Vicor’s ongoing commitment to developing<br />
the European market, especially Germany.<br />
This appointment will now allow Hannes to<br />
focus on our fast growing Eastern European<br />
territories”, says Andy Gales, Vice President<br />
of International Sales at Vicor.<br />
www.vicoreurope.com<br />
SolFocus Completes CPV Installation at ISFOC’s 3MW<br />
Solar <strong>Power</strong> Plant<br />
ducing testing facility for high-efficiency CPV<br />
technology. ISFOC sought the most promising<br />
CPV technologies approaching the electrical<br />
generation market, and selected SolFocus in<br />
advance of commercial production. SolFocus<br />
now enters the industrial, commercial, and<br />
utility markets having fine-tuned its design<br />
and technology development to emphasize<br />
reliability and overall system performance at<br />
the ISFOC installation. This month, the California<br />
Energy Commission (CEC) approved<br />
the SF-1000P CPV panel as the very first<br />
CPV product listed for commercial deployment<br />
in the state of California.<br />
www.solfocus.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
INDUSTRY NEWS<br />
General Manager Boosts Management Team at Gresham<br />
Gresham <strong>Power</strong> Electronics, the Salisbury,<br />
UK based MIL and commercial power solutions<br />
specialist, announces the appointment<br />
of Roger Diment to the position of General<br />
Manager. Roger comes to Gresham form<br />
Rolls Royce where he held a number of technical,<br />
commercial and logistics roles.<br />
Roger’s main focus will be to add further<br />
expertise to Gresham’s considerable global<br />
naval defence sales and to develop new<br />
markets in merchant marine power sys-<br />
tems. He will also assist with direct and distribution<br />
sales of Gresham’s high power density<br />
commercial OEM power supplies.<br />
Gresham <strong>Power</strong> is part of the power<br />
conversion empire formed of Telkoor <strong>Power</strong><br />
Supplies Ltd in Israel, a major supplier of MIL<br />
and custom commercial power solutions and<br />
Digital <strong>Power</strong>, the San Francisco based market<br />
leader in low profile, high power density<br />
OEM power supplies. This combination of<br />
global design and manufacturing expertise<br />
and very wide market experience offers a<br />
unique source of off the shelf and custom<br />
power conversion products with worldwide<br />
customer support.<br />
Roger has had a long career of working<br />
in “blue-chip” global solution suppliers and<br />
has worked in Europe and the Middle East<br />
providing technical and logistical services.<br />
He has had considerable experience of<br />
marine electrical system which will be a<br />
major asset for his new role with Gresham<br />
<strong>Power</strong>. He says. “I am convinced that many<br />
of Gresham’s MIL products will provide<br />
value for money solutions for the merchant<br />
marine market and I will be developing sales<br />
channels to develop this business. I am also<br />
looking forward to being involved in our commercial<br />
product sales and will be providing<br />
support to Telkoor’s direct sales in Europe.”<br />
Gresham <strong>Power</strong> provides static frequency<br />
converters, DC UPS, distributed power<br />
systems and DC:AC inverters for Naval defence<br />
systems and OEM power supplies and<br />
compactPCI products for telecoms, medical,<br />
industrial and commercial applications.<br />
www.greshampower.com<br />
High-Performance Two-Wheel Inverted Pendulum Robot<br />
via R&D Cooperation<br />
STMicroelectronics and the Waseda<br />
University Humanoid Robotics Institute (HRI)<br />
have announced the development of a high-<br />
performance two-wheel inverted<br />
pendulum robot, called WV-1<br />
(Waseda wheeled Vehicle-<br />
No.1), which is the first result<br />
of an ongoing cooperation for<br />
the research and development<br />
of technology and solutions for<br />
innovative humanoid robots and<br />
medical-care robot systems.<br />
ST and HRI are cooperating<br />
to use leading-edge semiconductor<br />
know-how to promote<br />
the speedier development of<br />
innovative ‘humanoids’ and<br />
medical-care robotic systems,<br />
involving researchers and development<br />
engineers from both<br />
ST and HRI. ST will become<br />
a supplier to HRI for semiconductor<br />
products, while also<br />
furnishing HRI with the leadingedge<br />
semiconductor prototypes<br />
on a cost-free basis, making it<br />
possible for HRI to conduct advanced<br />
evaluations of possible<br />
humanoid and medical-care<br />
robotic applications. In addition,<br />
future cooperation between<br />
ST and HRI is expected to<br />
include the establishment of<br />
an ST-sponsored scholarship system for HRI<br />
students.<br />
The WV-1 is a two-wheeled robot on which<br />
a pole with weights is installed in an inverted<br />
fashion on a pedestal. A feedback system,<br />
controlled with the STM32, ST’s ARM ®<br />
Cortex-M3 based 32-bit MCU and the<br />
LIS344ALH 3-axis digital acceleration sensor,<br />
allows the robot to move while maintaining<br />
its balance. The MCU rapidly computes the<br />
angle of robot body incline, angular velocity<br />
and other sensor data, enabling the motor to<br />
constantly generate optimum torque, which<br />
allows the robot to continue moving smoothly<br />
without tipping over. Potential applications for<br />
this inverted pendulum robot control technology<br />
include postural control functions for<br />
humanoids and other devices, realizing new<br />
means of mobility.<br />
HRI received a grant from “the project<br />
for reinforcement of development technologies<br />
for robotics” from The Robotics Industry<br />
Development Council. The grant was used<br />
for the development of the WV-1. Additionally,<br />
HRI is now working on plans to commercialize<br />
the robot.<br />
www.st.com<br />
www.humanoid.waseda.ac.jp<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
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Ultracapacitors for Backup<br />
<strong>Power</strong> in Wind Turbines<br />
Maxwell Technologies Inc. announced today that LTi REEnergy<br />
GmbH (LTi), one of the world’s leading producers of electro-mechanical<br />
wind turbine blade pitch control systems, has selected<br />
Maxwell’s BOOSTCAP ® Ultracapacitors to supply backup power for<br />
LTi’s PitchMaster ® blade pitch control system.<br />
Blade pitch control systems enhance the consistency of wind turbines’<br />
electrical energy output and ensure that rotor speed remains<br />
within a safe operating range by constantly adjusting turbine blades<br />
to compensate for changes in wind velocity. Ultracapacitors supply<br />
backup power for orderly system shutdown in the event of a main<br />
system power failure.<br />
David Schramm, Maxwell’s president and chief executive officer,<br />
said that LTi’s PitchMaster ® system incorporates multi-cell BOOST-<br />
CAP ultracapacitor modules based on Maxwell’s BCAP0350 “D cell”<br />
product.<br />
“LTi supplies blade pitch control systems to a number of major<br />
wind turbine manufacturers around the world, and already sold more<br />
than one thousand PitchMaster ® systems, so this new supply agreement<br />
represents a significant expansion of Maxwell’s penetration of<br />
the rapidly growing wind energy industry,” Schramm said. “We are<br />
pleased to be aligned with another leading player in the dynamic<br />
renewable energy marketplace.”<br />
Matthias Vehring, LTi’s Managing Director, said that ultracapacitors<br />
were chosen over batteries for backup power because of their<br />
longer operating life, lower maintenance requirements and ability to<br />
operate more reliably in harsh climates.<br />
“Wind turbine operators need systems that perform reliably for<br />
many years in all weather conditions with minimal maintenance,”<br />
Vehring said. “BOOSTCAP products have demonstrated their durability<br />
and reliability at temperatures ranging from -40 to +65 o C, which<br />
enables our pitch control systems to better meet our customers’<br />
expectations.”<br />
Industry sources report that nearly 20,000MW of new wind generator<br />
capacity was installed in 2007, bringing the total worldwide installed<br />
base to approximately 94,000MW. From 2003 through 2007,<br />
the industry maintained an annual growth rate of more than 20%,<br />
and it is projected to continue to meet or exceed that rate through<br />
2012.<br />
www.maxwell.com<br />
www.reenergy.lt-i.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
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drivers in portable equipment.<br />
21 Napier Place, Wardpark North, Cumbernauld UK G68 0LL<br />
+44/1236/730595 Fax +44/1236/730627
12<br />
INDUSTRY NEWS<br />
Microsemi Appoints Bel Lazar Senior VP of Operations<br />
Microsemi Corporation has announced<br />
the appointment of Bel Lazar as Senior Vice<br />
President of Operations, reporting to Ralph<br />
Brandi, Executive Vice President and Chief<br />
Operating Officer.<br />
Lazar comes to Microsemi from International<br />
Rectifier, where he was Vice President of<br />
the Aerospace & Defense Business Unit, having<br />
responsibilities for operations in Leominster,<br />
Massachusetts, Santa Clara, California,<br />
and Denmark.<br />
“We are excited to welcome Bel to Microsemi,”<br />
said Ralph Brandi. “Microsemi has<br />
entered exciting new territory in the last year,<br />
introducing a number of RadHard parts for<br />
military and aerospace applications, with<br />
more products on the roadmap for release<br />
in the near future. These are some of the<br />
most profitable high-reliability markets and<br />
TTI Signs Pan-European Franchise Deal with C&K Components<br />
TTI, Inc. a leading passive, connector and<br />
electro-mechanical specialist distributor in the<br />
electronics industry, has signed a distribution<br />
agreement with C&K Components, a recognized<br />
leader in the design and manufacture<br />
of switches, smart card interconnect devices,<br />
and high reliability connectors. C&K is known<br />
throughout the world as one of the most relied<br />
upon switch manufacturers and offers the<br />
broadest portfolio of switch products as well<br />
as specialty connectors.<br />
Comments John Sandy, TTI’s European Director<br />
Supplier Marketing Connectors: “There<br />
is no doubt that C&K is one of the world’s<br />
leading switch brands. I’m confident that our<br />
current switch portfolio allows us to address<br />
any and all market requirements.”<br />
Adds Henk Raaijmakers: C&K Components’<br />
Distribution Manager Switches for Cen-<br />
Lineage <strong>Power</strong> Corporation has announced<br />
that Chris Meaney has been appointed global<br />
vice president of OEM sales. Meaney will be<br />
responsible for driving the global sales strategy<br />
for the OEM (original equipment manufacturers)<br />
market.<br />
Most recently, Meaney served as vice<br />
president of sales at IntraLinks, a leading<br />
provider of virtual data room workspaces and<br />
other online workflow management solutions.<br />
Primarily responsible for the regional<br />
direct sales team, Meaney played a key role<br />
in generating a $14 million revenue stream.<br />
Before IntraLinks, Meaney held multiple sales<br />
positions for Siemens Enterprise Communications,<br />
where he managed regional and global<br />
accounts, such as Coca-Cola, IBM, UPS and<br />
Ford Motor Company. Meaney also served<br />
as multi-services regional manager at Cisco<br />
<strong>Systems</strong>.<br />
represent an entirely new growth opportunity<br />
for the company. Bel's deep understanding of<br />
these technologies and applications makes<br />
him an integral part of the team and a key<br />
component of our next generation growth<br />
strategy.”<br />
Lazar, who has a Juris Doctor degree<br />
from Southwestern University School of<br />
Law, earned a Master of Science degree in<br />
Computer Engineering from the University of<br />
Southern California in 1986 and a Bachelor<br />
of Science degree in Electrical Engineering<br />
from California State University, Northridge, in<br />
1984.<br />
tral & Nordic Europe: “TTI is very focused on<br />
our sector and has a track record of targeting<br />
new business rather than just trying to take<br />
market share. Customers will have access to<br />
a wide range of our products stocked in depth<br />
by TTI.”<br />
Lineage <strong>Power</strong> Appoints Global VP of OEM Sales<br />
www.microsemi.com<br />
www.ck-components.com<br />
Meaney earned his bachelor’s degree in<br />
electrical engineering from the University of<br />
Vermont. He will be based in Atlanta.<br />
www.lineagepower.com<br />
<strong>Power</strong> Events<br />
electronicAsia 2008,<br />
October 13-16, Hong Kong, China,<br />
www.electronicasia.net<br />
electronica 2008,<br />
November 11-14, Munich, Germany,<br />
www.electronica.de<br />
SPS/IPC/Drives 2008,<br />
November 25-27, Nürnberg, Germany,<br />
www.mesago.de/en/SPS/main.htm<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
14<br />
Energy-Efficient Chokes<br />
for <strong>Transportation</strong><br />
SMP Sintermetalle Prometheus<br />
GmbH & Co KG, manufacturers<br />
of inductive components and<br />
magnetically soft materials, cores and<br />
mouldings is based in Graben-Neudorf<br />
near Karlsruhe, Germany and has introduced<br />
a range of chokes designed<br />
specifically for use with inverters. The<br />
special feature of these units is their<br />
ingress protection class of IP66, which<br />
makes them suitable for use in tough<br />
environments as found in rail transportation,<br />
to restrict incoming current on the<br />
line side.<br />
Because of the high degree of protection,<br />
these chokes can be fitted outside<br />
the inverters, so the heat generated by<br />
the choke is not discharged inside the<br />
inverter. This results in a lower internal<br />
inverter temperature, which removes<br />
the need for cooling fans, saving both<br />
energy and installation space. Placing<br />
the choke outside the inverter has<br />
the further advantage of reducing the<br />
inverter’s overall dimensions, which<br />
further cuts space and energy demand.<br />
For the choke itself, external mounting<br />
has the benefit of allowing it to be designed<br />
for lower ambient temperatures.<br />
While inverters, for example in railway<br />
applications, can have an internal<br />
temperature of 70 to 80°C, the outside<br />
temperature to which underfloor-mounted<br />
electronics are exposed is unlikely to<br />
exceed about 40°C. SMP has developed<br />
chokes for external mounting even<br />
for use on offshore oil platforms. Their<br />
special protective paint coating protects<br />
these components from direct sunlight,<br />
sea water, rain and corrosive gasses.<br />
To simplify mounting outside the<br />
inverters, SMP provides the chokes with<br />
special mounting fixtures. The choke<br />
and the mounting plate are fitted on the<br />
device’s outside and the connecting<br />
cables pass through a sealed opening.<br />
SMP choke for railway applications.<br />
To meet demanding requirements in<br />
power electronics, SMP has developed<br />
high-performance chokes and filters.<br />
These inductive components offer a high<br />
energy storage capacity at low volume,<br />
reduced losses, good EMC characteristics<br />
and a cost-conscious design.<br />
Depending on their application, they are<br />
constructed either as single-conductor<br />
chokes for high-current applications,<br />
individual chokes, choke modules or LC<br />
filters.<br />
For wider applications in power electronics,<br />
power generation, instrumentation<br />
and control, SMP supplies chokes<br />
and filters for frequencies up to 200kHz<br />
and current ratings up to 1000 amperes,<br />
with component sizes ranging from 36<br />
to 300mm diameter and weights from<br />
50g to 130kg. The components can<br />
be used in a temperature range up to<br />
180°C. They are easy to fit and, with<br />
numerous mounting options, can be<br />
mounted according to the available<br />
space. To allow for a wide range of requirements,<br />
components can be made<br />
to all common standards, including protection<br />
type IP20 and IP65. All products<br />
are RoHS- and WEEE-conformant and<br />
the materials used are UL-listed.<br />
www.smp.de<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
16<br />
Optimized <strong>Power</strong> Processing<br />
and Energy Efficiency<br />
By Oleg Khaykin, President and Chief Executive Officer, International Rectifier<br />
<strong>Power</strong> management plays a key<br />
role in enabling energy efficiency<br />
advancements in the vast number<br />
of products that we depend on as we<br />
go about our daily lives. However, it’s a<br />
term that has been misused by companies<br />
looking to gain traction with Internet<br />
keywords optimized for Google and Yahoo<br />
searches as they seek to exploit the<br />
growing buzz around saving the world’s<br />
dwindling energy reserves.<br />
So what exactly is power management?<br />
It is power sequencing or communication<br />
and in some cases, regulation,<br />
and it is the first link in the power<br />
processing chain. To achieve real power<br />
savings in a system, the integration of<br />
multiple components is required that<br />
encompasses both the power management<br />
and the power conversion stages.<br />
When you combine load-centric<br />
power conversion with system-centric<br />
power management, you have a better<br />
chance of improving efficiency within an<br />
application. This is the essence of optimized<br />
power processing. The result is<br />
longer battery life, fewer kilowatt hours<br />
when your notebook is plugged into the<br />
wall, or more functionality from your cell<br />
phone because each component is being<br />
managed more efficiently.<br />
The opportunity to save energy using<br />
this approach is enormous. Take the data<br />
center as an example. Information about<br />
the power load needs to be combined<br />
with information going on at the board level,<br />
inside the server rack and in the entire<br />
room to maximize efficiency. This doesn’t<br />
happen when components aren’t integrated<br />
effectively, and with data centers now<br />
consuming as much as 3 percent of all<br />
power, there is growing pressure to curb<br />
their energy consumption.<br />
more than 80 percent of these motors<br />
are wastefully controlled electro-mechanically.<br />
<strong>Design</strong>s are moving towards<br />
variable-speed permanent magnet motors<br />
that are smaller, lighter and lower<br />
cost, and as long as you have a good<br />
control technique, permanent magnet<br />
inverterized motor control can achieve<br />
95 percent efficiency by co-designing<br />
the power train and the driver, and an<br />
algorithm to control them.<br />
This all points back to power processing<br />
and engineers are forced into making<br />
tradeoffs between higher efficiency and<br />
maximum cost-effectiveness, or to deliver<br />
efficiency and density at a higher price.<br />
These issues can be solved by providing<br />
complete solutions from switch to<br />
drive scheme to power management.<br />
Matching and optimizing digital and<br />
analog control with power stage components,<br />
and integrating them with new<br />
packaging technologies will continue<br />
to increase the power density with less<br />
wasted energy while simultaneously reducing<br />
system size, complexity and cost.<br />
others, new materials are needed. As a<br />
market leader, it is natural for IR to pursue<br />
opportunities for advancing power<br />
conversion technology by leveraging the<br />
company’s 60-year heritage in power<br />
conversion expertise in AC-DC converters,<br />
DC-DC converters, motor drives<br />
and lighting systems.<br />
The advent of GaN on Silicon epitaxial<br />
technology together with the ability to<br />
develop a process that is compatible<br />
with IR’s silicon manufacturing facilities<br />
allows IR to offer customers commercially<br />
viable products using GaN-based<br />
power devices.<br />
These devices can provide customers<br />
with improvements in key applicationspecific<br />
figures of merit (FOM) of up to a<br />
factor of ten compared to state-of-theart<br />
silicon-based technology platforms,<br />
dramatically increasing performance<br />
and cutting energy consumption in end<br />
applications in market segments including<br />
computing and communications,<br />
automotive and appliances.<br />
GaN-based power devices will eventually<br />
be used in most of the same applications<br />
as current silicon-based power<br />
devices, as well as new applications currently<br />
not possible with silicon devices.<br />
These applications will evolve over the<br />
coming decades, as GaN-based power<br />
devices replace silicon based power<br />
devices as the technology platform of<br />
choice. Early adopters will be market<br />
segments and applications that take full<br />
advantage of the revolutionary capability<br />
of transforming the value realization of<br />
the key features of power density, power<br />
conversion efficiency and cost.<br />
All of these innovations are geared<br />
toward achieving more functionality using<br />
significantly less power—and a sharp<br />
reduction in the number of buzzwords<br />
needed to accomplish it.<br />
Electric motors present another<br />
golden opportunity. Consuming over In some cases, new techniques are<br />
50 percent of the world’s electricity, required for building components and in<br />
www.irf.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
© 2008, National Semiconductor Corporation. National Semiconductor, , and <strong>Power</strong>Wise are registered trademarks. All rights reserved.<br />
N o v e m b e r 1 1 – 1 4<br />
See us at our booth A4.506<br />
national.com/LED<br />
High Brightness. Low <strong>Power</strong>.<br />
Energy-Effi cient LED Lighting Solutions<br />
National Semiconductor’s <strong>Power</strong>Wise ® lighting solutions have the best power-toperformance<br />
ratios, offer a wide variety of features including dimming and thermal<br />
management to extend the life of LEDs, minimize external component count, and<br />
enable robust designs.<br />
Automotive Lighting<br />
Architectural Lighting<br />
National’s easy-to-use<br />
constant-current LED drivers<br />
drive up to 20 LEDs in series,<br />
provide greater than 90%<br />
effi ciency, and offer accurate<br />
current control, dimming and<br />
thermal performance for indoor<br />
and outdoor architectural<br />
lighting applications.<br />
Architectural Lighting<br />
Outdoor Lighting<br />
National’s ultra high-efficiency<br />
and high-reliability LED<br />
drivers with wide operating<br />
voltage range help customers<br />
minimize total system cost<br />
by driving up to 20 LEDs in<br />
one string. At the same time,<br />
thermal management ICs<br />
supply accurate temperature<br />
information to avoid LED<br />
overheating.<br />
Outdoor Lighting<br />
Automotive Lighting<br />
Robust protection and fault<br />
fl ag at over-current, overvoltage<br />
and over-temperature<br />
make National’s LED drivers<br />
ideal solutions for highreliability<br />
automotive exterior,<br />
interior and back lighting<br />
systems.
18<br />
Portable <strong>Power</strong>- Management<br />
Market Throws the Switch<br />
Revenue expected to grow to $7.8 billion by 2012<br />
Booming sales of portable devices<br />
capable of accessing the Internet<br />
have spurred fast growth in<br />
demand for power-management semiconductors<br />
for this application, according<br />
to iSuppli Corp.<br />
Global portable power management<br />
semiconductor revenue will expand to<br />
$7.8 billion by 2012, rising at a Compound<br />
Annual Growth Rate (CAGR) of<br />
10.6 percent from $4.7 billion in 2007.<br />
Figure 1 presents iSuppli's revenue<br />
forecast for power-management<br />
semiconductors for the period of 2007<br />
through 2012.<br />
Notebook PCs and 3G mobile handsets<br />
will be the biggest markets for<br />
power-management semiconductors,<br />
registering CAGRs of 18.7 percent and<br />
26.8 percent respectively from 2007 to<br />
2012.<br />
Sales of portable power-management<br />
semiconductors are being driven by<br />
the need for more efficient electrical<br />
consumption by power-hungry microprocessors,<br />
memories and audio and<br />
video application ICs. This requirement<br />
is only increasing as today's users are<br />
demanding greater<br />
mobility, more content,<br />
enhanced functionality,<br />
longer battery life<br />
and increased power<br />
for components.<br />
Getting efficient<br />
As mobile devices'<br />
functionality has<br />
increased and their<br />
energy-usage requirements<br />
have become<br />
more stringent,<br />
designers and OEMs<br />
By Marijana Vukicevic, iSuppli Corp.<br />
have embraced power-management<br />
semiconductor integration as a means<br />
to improve efficiency.<br />
Rising integration more than likely will<br />
limit sales growth for more traditional,<br />
discrete solutions. For suppliers, future<br />
growth will hinge on offering more<br />
integrated solutions, such as highly integrated<br />
switching regulators or <strong>Power</strong><br />
Management Units (PMUs), iSuppli<br />
believes.<br />
Furthermore, the phase out of discrete<br />
low-power MOSFETS in notebook<br />
PCs will be delayed with upcoming<br />
Intel Corp. microprocessors because<br />
the increased power demands from the<br />
company's new quad-core chips.<br />
<strong><strong>Power</strong>ing</strong> up<br />
Discrete solutions will face particular<br />
challenges competing against more<br />
integrated alternatives in the mobile<br />
handset market. In order to survive,<br />
discrete suppliers must shift their efforts<br />
to the integrated solutions, iSuppli<br />
believes.<br />
Texas Instruments Inc. has done this<br />
by utilizing its expertise in both the<br />
wireless and power-management markets<br />
to benefit in the integrated market.<br />
Qualcomm has done the same thing,<br />
although not by using organic means.<br />
Integrated solutions require major<br />
investments in development and the<br />
majority of traditional discrete solution<br />
providers will face difficulties when trying<br />
to expand their business in the wireless<br />
market.<br />
As users demand more content from<br />
their portable devices<br />
and big entertainment<br />
companies shift their<br />
business models to<br />
take advantage of<br />
such products, power<br />
management will only<br />
play an increasingly<br />
crucial role in enabling<br />
these applications<br />
to be brought to the<br />
masses.<br />
www.isuppli.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
20<br />
DESIGN TIPS<br />
<strong>Power</strong> Supply Control<br />
<strong>Design</strong> Tools – Part VI<br />
Modeling <strong>Power</strong> Supplies with<br />
Current-Mode Control<br />
The buck-boost converter (or flyback<br />
converter in its isolated version) is the<br />
most popular converter for generating<br />
low power with multiple output voltage<br />
levels. The converter can be run in<br />
many different modes – discontinuous<br />
conduction mode (DCM), continuous<br />
conduction mode(CCM), quasi-resonant<br />
mode (DCM with switching at the bottom<br />
of the DCM ring wave), and various<br />
options of fixed or variable frequency.<br />
The choice of operation depends on<br />
the power level, the application, and the<br />
control chip used.<br />
Regardless of the mode of operation<br />
of the power stage, current-mode<br />
control is almost always used, as<br />
shown in Figure 1. Many designers<br />
strive to always keep their converter<br />
in DCM in order to avoid some of the<br />
complexities of control. This is not<br />
necessary if current mode control is<br />
used, and keeping the converter DCM<br />
under every condition of line and load<br />
can create large peak stresses in the<br />
semiconductors.<br />
While it is an intuitive control scheme,<br />
the proper analysis of current mode<br />
control is complex. The dynamic analysis<br />
of current mode involves advanced<br />
techniques, including discrete-time and<br />
sampled-data modeling. This is essential<br />
Buck-Boost Converter with<br />
Current-Mode Control<br />
In this article, Dr. Ridley presents a summary of current-mode control for the buck-boost converter.<br />
A free piece of analysis software, the final one in a series of six, is provided to readers of this column to<br />
aid with the analysis of their current-mode buck-boost converters.<br />
By Dr. Ray Ridley, Ridley Engineering<br />
to arrive at a model which explains all of<br />
the phenomena seen with your converter,<br />
and which accurately predicts the<br />
measured control-to-output response<br />
and loop gain of the current-mode converter.<br />
The full analysis of current-mode<br />
control can be downloaded from www.<br />
ridleyengineering.com.<br />
Figure 2 shows a plot of the control<br />
characteristics of the buck-boost converter<br />
in both DCM and CCM. Notice<br />
that these characteristics do not change<br />
very much at low frequencies, making<br />
control optimization straightforward for<br />
converters that must operate in both<br />
regions.<br />
There are several important points<br />
to learn from the full analysis of the<br />
current-mode boost converter:<br />
1. The power stage has a dominantpole<br />
response at low frequencies,<br />
determined mainly by the time constant<br />
of the output capacitor and load resistor<br />
values. This dominant pole response<br />
does not vary significantly as the converter<br />
moves from DCM to CCM operation,<br />
as can be seen in Figure 2.<br />
2. In CCM, the power stage has an<br />
additional pair of complex poles at half<br />
the switching frequency which, under<br />
certain conditions, will create instability<br />
in the current feedback loop. The<br />
damping of these complex poles is<br />
controlled by the addition of a compensating<br />
ramp.<br />
3. The resulting transfer function of the<br />
CCM power stage is third-order, even<br />
though there are only two state variables<br />
in the converter. (This apparent anomaly,<br />
for control theorists, is caused by the<br />
fact that the switching power converter<br />
is a nonlinear, time-varying system.)<br />
4. The second-order double poles at<br />
half the switching frequency cannot be<br />
ignored, even though they may be well<br />
beyond the predicted loop crossover<br />
frequency.<br />
5. The capacitor ESR zero is unchanged<br />
by the presence of the current<br />
loop feedback.<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
DESIGN TIPS DESIGN TIPS<br />
Figure 1: Buck-boost converter with current-mode control. The green components show the current feedback; without these,<br />
the control is voltage-mode.<br />
6. Finally, and most importantly, the<br />
current-mode boost converter retains<br />
the exact same RHP zero as the<br />
voltage-mode converter. However, since<br />
the current feedback has eliminated the<br />
double poles of the filter resonance, it<br />
is not difficult to control this RHP zero<br />
effectively.<br />
As explained in reference [1],<br />
current-mode control has many advantages.<br />
These include elimination<br />
of the resonant filter frequency, the<br />
ability to current share with multiple<br />
power stages, simplified compensation<br />
design, and inherent peak current<br />
limiting.<br />
<strong>Design</strong>ing with Current-Mode Control<br />
While the analysis of current-mode<br />
control is quite complex to understand,<br />
the design process is quite simple.<br />
Much simpler, in fact, than voltagemode<br />
control, and this is one of the<br />
reasons that current-mode control is so<br />
popular today.<br />
The switch current of the circuit of<br />
Figure 1 is sensed and compared to a<br />
voltage reference to set the duty cycle<br />
of the converter. A sawtooth ramp is<br />
added to the signal to stabilize the current<br />
loop. For the buck-boost converter,<br />
it is recommended to use a stabilizing<br />
ramp at greater than 40% duty cycle in<br />
Figure 2: Response of the buck-boost converter with current-mode control in both<br />
CCM and DCM operating modes. At lower frequencies, the characteristics do not<br />
significantly change, and this is an important advantage of current-mode control.<br />
CCM operation.<br />
Closing the current loop is straightforward.<br />
A current transformer, or sense<br />
resistor, is used to generate a voltage<br />
signal proportional to the current in the<br />
switch. The only requirement on the<br />
design of this network is that the resulting<br />
signal should not exceed the voltage<br />
headroom available in the PWM comparator.<br />
You do not have to think about<br />
the gain of the current loop, or resulting<br />
transfer functions at all during this phase<br />
of the design.<br />
Once the current sense network is<br />
selected, you must decide whether you<br />
need to add a compensating ramp to<br />
the system. Further details of how to<br />
add the ramp are given in [1]. Addition<br />
of the compensating ramp provides independent<br />
control of the PWM modulator<br />
gain.<br />
Buck-Boost Converter Current-<br />
Mode Software<br />
Software is available for download<br />
that allows you to predict the smallsignal<br />
response of your buck-boost<br />
converter with current-mode control.<br />
After entering your power stage values<br />
and switching frequency, you can<br />
design the current loop parameters of<br />
current gain, and compensating ramp<br />
value. The software will help you choose<br />
the proper values. Once this is done, the<br />
transfer function gain and phase of the<br />
power stage is plotted for you, and the<br />
resulting poles and zeros given.<br />
The software is designed to run under<br />
either Excel 2007 or Excel 2003. Make<br />
sure when you open the software that<br />
the macro features are enabled in order<br />
to use the program properly. Please go<br />
to www.ridleyengineering.com to download<br />
the software.<br />
Summary<br />
If you work with a buck-boost converter,<br />
it is advisable to use currentmode<br />
control, even if you operate the<br />
converter in DCM. While the analysis is<br />
complex, the software tool made avail-<br />
able with this article will help you design<br />
the current loop properly and show<br />
the transfer functions of the converter.<br />
Remember, however, the results of any<br />
power supply transfer functions should<br />
always be verified by measurement.<br />
<strong>Power</strong> systems are frequently dependent<br />
on circuit component parasitics<br />
that can be unpredictable, and can also<br />
be impacted by noise and improper<br />
board layout. Experimental verification<br />
[2] is an essential step for a rugged design,<br />
and should never be omitted.<br />
References<br />
1. “A New Small-signal Model for<br />
Current-Mode Control”, Raymond B.<br />
Ridley,1990 PhD dissertation, free download<br />
is available at www.ridleyengineering.com/cmode.htm<br />
2. “Measuring Frequency Response,<br />
Tips and Methods” http://www.ridleyengineering.com/downloads/Spring<br />
2002<br />
feature.pdf<br />
www.ridleyengineering.com<br />
22 <strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
www.powersystemsdesign.com<br />
23
24<br />
ON THE ROAD<br />
On the Road<br />
Reported by Cliff Keys, Editor-in-Chief, PSDE<br />
I visited Fairchild’s facility in Portland, Maine, US, and had the opportunity to speak with Guy Moxley,<br />
Fairchild’s Senior Director of Low Voltage Marketing. He took me through the company’s latest<br />
contribution to their drive for industry power efficiency.<br />
Fairchild’s Next Generation DrMOS Delivers 92% Efficiency<br />
Fairchild’s Multi-Chip Modules follow<br />
the traditional definition in that they are<br />
the integration of switching, control and<br />
driver ICs, and passive components<br />
to form a system to achieve the most<br />
optimal solution for a given application<br />
using components that are matched<br />
electrically, thermally and mechanically.<br />
The ever problematic EMI has been<br />
minimized by Fairchild’s engineers by<br />
judicious layout and lead configuration<br />
within the module itself to provide a<br />
complete solution.<br />
TinyBuckTM Multi-Chip Module with Intelstandard<br />
DrMOS driver plus MOSFETs.<br />
With today’s increased focus on efficiency,<br />
several government organizations<br />
are driving energy efficiency initiatives<br />
such as Energy Star and Climate<br />
Savers by Google and Intel who are driving<br />
for significant reduction of electricity<br />
costs in servers by IT departments,<br />
increased focus on smaller form factors<br />
for blade and rack servers and smaller<br />
desktop PCs.<br />
TinyBuckTM is Fairchild’s family<br />
of fully-integrated synchronous buck<br />
converter switching regulator solutions.<br />
These products include a controller IC,<br />
a driver IC, one high-side MOSFET one<br />
low-side MOSFET in a space-¬efficient<br />
MLP package.<br />
DrMOS is an Intel standard that defines<br />
the specifications and functionality<br />
of a FET-plus-Driver multi-chip module.<br />
Fairchild worked extensively with Intel on<br />
the development of this specification and<br />
offers an extensive portfolio of DrMOS<br />
modules in two versions: 8mmX8mm<br />
and 6mmX6mm MLP packages.<br />
Fairchild’s DrMOS, the FDMFxxxx series,<br />
is a complete family of fully optimized,<br />
integrated FET-plus-Driver multi-chip power<br />
stage modules designed for multiple<br />
synchronous buck converter applications.<br />
These multi-chip modules are designed to<br />
achieve the optimal solution using components<br />
that are accurately matched.<br />
Fairchild Semiconductor has recently<br />
introduced its XS DrMOS, the industry’s<br />
first high-performance and spaceefficient<br />
6mm x 6mm DrMOS solution<br />
for synchronous DC-DC buck regulators<br />
for computing, game console and<br />
consumer Point-of-Load (POL) applications.<br />
The FDMF6704 is a FET-Plus-<br />
Driver module that replaces one driver<br />
IC, one high-side MOSFET, two low-side<br />
MOSFETS and one bootstrap Schottky<br />
diode in an ultra-compact package. The<br />
thermally enhanced 6mm x 6mm MLP<br />
package saves 84 percent board space<br />
compared to discrete solutions and 44<br />
percent compared to 8mm x 8mm MLP<br />
packaged DrMOS modules. It delivers<br />
92 percent peak efficiency, enabling<br />
applications to meet stringent energy-efficiency<br />
specifications such as ENERGY<br />
STAR ® , Climate Savers ® and Green<br />
Grid SM .<br />
The XS DrMOS family is<br />
Fairchild’s next-generation fully optimized<br />
ultra-compact integrated MOSFET<br />
plus driver power stage solution for high<br />
current, high frequency synchronous<br />
buck DC-DC applications. With an integrated<br />
approach, the complete switching<br />
power stage is optimized with regards<br />
to driver and MOSFET dynamic performance,<br />
system inductance and R DS(ON).<br />
This greatly reduces the package parasitics<br />
and layout challenges associated<br />
with conventional discrete solutions. The<br />
driver IC incorporates advanced features<br />
such as SMOD. PWM input is Tri-<br />
State compatible. A 5V gate drive and<br />
an improved PCB interface [Low Side<br />
MOSFET exposed pad] ensure higher<br />
performance. This product is compatible<br />
with the new Intel 6mm x 6mm DrMOS<br />
specification.<br />
With an abundance of advanced<br />
features, the FDMF6704 has been<br />
designed and optimized to work with a<br />
wide variety of controllers in the market.<br />
It is compatible with both Tri-State and<br />
Non-Tri-State PWM controllers. To fur-<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
26<br />
ON THE ROAD<br />
ther ensure compatibility, the FDMF6704<br />
has its PWM threshold levels tailored to<br />
meet a broad range of controllers available<br />
in the market. Fairchild’s advanced<br />
SyncFET technology is integrated<br />
within the module’s low-side MOSFET<br />
further ensuring higher performance.<br />
The FDMF6704 utilizes lead-free (Pbfree)<br />
terminals and has been characterized<br />
for moisture sensitivity in accordance<br />
with the Pb-free reflow requirements<br />
of the joint IPC/JEDEC standard<br />
J-STD-020. All of Fairchild’s products<br />
are designed to meet the requirements<br />
of the European Union’s Directive on the<br />
restriction of the use of certain substances<br />
(RoHS).<br />
electronica: Hall A4 Stand 121<br />
TI Launches Industry-Thinnest 500 mA Converter Solution<br />
www.fairchildsemi.com<br />
At TI’s recent press conference in Freising, Germany, I was able to get the company’s latest in good<br />
news from TI for portable equipment designers from Uwe Mengelkamp, Director DC/DC Converters<br />
(worldwide) for Texas Instruments.<br />
Texas Instruments announced the<br />
industry’s smallest and thinnest 500mA,<br />
step-down DC/DC converter solution<br />
for space-constrained applications. The<br />
new product, TPS62601, gives portable<br />
designers the unique ability to add more<br />
features and functions on a handheld<br />
device. This high-efficiency power<br />
management integrated circuit is the<br />
first 6MHz, 500mA converter to achieve<br />
a 13mm 2 solution size with an ultra-thin<br />
0.6mm total height, vital for competitive<br />
advantage in portable devices.<br />
Leveraging TI’s long standing analog<br />
manufacturing technology, the new<br />
TPS62601 converter achieves up to 89%<br />
power efficiency and only 30µA typical<br />
operating quiescent current – all from<br />
a 0.9mm x 1.3mm chip scale package<br />
roughly the size of a flake of pepper. The<br />
synchronous, switch-mode device’s fixed<br />
frequency of 6 MHz allows the use of<br />
only one 0.47µH inductor with a height of<br />
0.6mm and two low-cost ceramic capacitors,<br />
without compromising performance<br />
and efficiency.<br />
“Portable system designers continue<br />
to desire more features on their devices,<br />
Texas Instruments<br />
Uwe Mengelkamp, Director DC/DC Converters<br />
(worldwide) for TI.<br />
which require smaller, efficient DC/DC<br />
converters to maintain long battery life<br />
and system run-times,” said Uwe Mengelkamp,<br />
Director DC/DC Converters, TI.<br />
“The TPS62601 gives portable designers<br />
access to the smallest, thinnest 500mA<br />
DC/DC solution, which simplifies design<br />
and reduces board space and time-tomarket.”<br />
The TPS62601 can deliver DC voltage<br />
regulation accuracy of +/-1.5%. In addition,<br />
the device’s excellent load transient<br />
response, wide input voltage range of<br />
2.3 V to 5.5V and 1.8V of output allows<br />
it to effectively support single-rail voltage<br />
requirements as designers add new features<br />
and functionality. The TPS62601<br />
supports many applications, such<br />
as memory modules, GPS modules,<br />
wireless micro-modules used in ultrathin<br />
smart phones, digital still cameras,<br />
portable disk drives and media players.<br />
The converter also applies energysaving<br />
techniques to help maximize battery<br />
run-time. For example, the converter<br />
automatically enters a power save mode<br />
during light-load operating conditions via<br />
an automatic pulse frequency modulation<br />
and pulse width modulation switching<br />
feature. In shutdown mode, the<br />
device’s current consumption is reduced<br />
to less than 1µA.<br />
The TPS62601 is available immediately<br />
in volume from TI and its authorized<br />
distributors. The device comes<br />
in a highly reliable, six-pin, wafer chip<br />
scale (0.9mm x 1.3mm) package and<br />
has a suggested resale price of $1.45<br />
each in quantities of 1,000 units. The<br />
TPS62601EVM-327 evaluation module,<br />
application notes and TI’s online <strong>Power</strong><br />
Management selection tool are available<br />
through power.ti.com.<br />
In addition to the TPS62601, TI provides<br />
a broad range of power management<br />
battery management solutions for<br />
handheld devices. Examples include<br />
the new 3-MHz bq24150, switch-mode<br />
battery charger integrated circuit, the<br />
system-side bq27500 battery fuel gauges,<br />
and TI’s DC/DC converters that support<br />
RF power amplifiers and core supply voltages.<br />
Complete system block diagrams<br />
with analog and digital solutions for<br />
OMAP 3 processor-based applications<br />
can be found at: www.ti.com/omap3.<br />
electronica: Hall A4 Stand 414<br />
Bluetooth and Wi-Fi modules or other www.ti.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
Sensorless Field-Oriented<br />
Motor Control<br />
Improve your current motor control<br />
design with FOC<br />
• Gain Higher Energy Efficiency<br />
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GET STARTED NOW...<br />
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Microchip also offers a variety of low-cost<br />
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• Download FREE MOTOR CONTROL SOFTWARE LIBRARIES – including FOC Sensorless<br />
PMSM or ACIM, as well as on-chip power-factor correction algorithms<br />
• Request FREE SAMPLES of dsPIC ® Digital Signal Controller optimized for motor control<br />
• See the Microchip website for the current MOTOR CONTROL PROMOTIONS AND DISCOUNTS!<br />
• FULL TECHNICAL SUPPORT 24/7 - including webinars, application notes & technical training classes<br />
Visit www.microchip.com/DSCMotor today<br />
www.microchip.com<br />
The Microchip name, logo and dsPIC are registered trademarks of Microchip Technology Incorporated in the USA and other countries. All other trademarks and registered trademarks are the property<br />
of their respective owners. © 2008 Microchip Technology Inc. All rights reserved. ME190Eng/03.08
ON THE ROAD ON THE ROAD<br />
Sharp Microelectronics Europe<br />
I had the great pleasure and opportunity to attend the Sharp Innovation forum held in the beautiful south<br />
of Germany recently. Within the assembled press, I was very interested to see the presentations of the<br />
company’s technology experts where I captured much information for future publication. Maximilian Huber,<br />
President Sharp Microelectronics Europe gave us all an update of the Sharp of today going forward.<br />
Although the status of Sharp in the display arena is well known and accepted, Maximilian spelled out the<br />
major goals set for the company.<br />
Innovation Forum Overview<br />
Sharp now invests about 5.7% of its<br />
annual net sales in Research and Development<br />
with approximately 1.22 Billion<br />
Euros invested in FY 2007.<br />
Worldwide 8,200 researchers are<br />
working to drive Sharp’s appropriately<br />
called “one-of-a-kind” innovation in technology<br />
areas of LCD, Opto electronics<br />
and IC components.<br />
Sharp’s global R&D network is built<br />
on five bases in four countries to ensure<br />
close proximity to relevant centers of<br />
excellence for the company’s wide ranging<br />
technology fields. Close contact with<br />
localized universities ensure efficient<br />
technology transfer to keep Sharp at the<br />
cutting edge of its business areas.<br />
Large-size LCDs<br />
At the forum, Sharp announced the<br />
world’s first 108 inch monitor. This<br />
hugely impressive display will be on<br />
show at electronica in Munich, Germany.<br />
The company’s G8 and G10 factory is<br />
optimized for increased efficiency for AV<br />
and e-signage display manufacturing.<br />
LEDs for lighting<br />
Sharp is Increasing LED efficiency for<br />
new display backlighting and lighting<br />
systems with more natural colors, higher<br />
robustness, less power consumption and<br />
flexible utilization.<br />
Green Products<br />
Throughout the world, there are approximately<br />
1.2 Billion CRT TVs in operation.<br />
If they were all replaced by LCD TV<br />
with Sharp’s new technology, the reduction<br />
of energy consumption would stand<br />
at around 100 Billion kWh per year. This<br />
is equivalent to the annual capacity of 14<br />
power plants or 34 Million tons of CO 2.<br />
Maximilian Huber, President, Sharp<br />
Microelectronics Europe.<br />
General targets for Sharp’s green factories<br />
of the future include the reduction<br />
of CO 2-emissions per output unit (2%<br />
reduction per year) together with the<br />
aggressive goal of “Zero Waste” which<br />
means that only a meagre 0,5% of waste<br />
is committed to landfill.<br />
A good example of this is the LCD-<br />
Factory in Kameyama where a co-generation<br />
system and solar cells produce<br />
over 30% of the power needed. CO 2emissions<br />
are reduced by 40% and<br />
100% of water consumed is re-used in<br />
the production process.<br />
Display market overview<br />
TV: Sharp is focused on significantly<br />
increasing its market share of LCD TV<br />
from today’s 37% to 68% by 2011.<br />
e-signage: the company’s goal is for<br />
an 11-fold increase in volume of LCD<br />
e-signage displays in EMEA markets<br />
from 336k units in 2007 to 3.8 Million<br />
units in 2011.<br />
PC Market: LCDs currently account<br />
for 90% of all PC monitor sales.<br />
Automotive: Sharp predicts the market<br />
for navigation systems (fixed + PND)<br />
will double from 45 Million units in 2007<br />
to 90 Million units in 2010.<br />
Portable Applications: A steady<br />
volume increase on high level (4 Billion<br />
units in 2007), with a technology shift<br />
towards active matrix displays.<br />
Sharp predicts that overall, LCDs will<br />
continue to be a growth driver for the<br />
foreseeable future.<br />
LCD: One Technology does it all<br />
This is a mature technology with large<br />
potential for further innovation. The reliable<br />
technology delivers ever more brilliant<br />
images for consumers and enables<br />
production of displays flexible in size:<br />
from 1.5 inch to 108 inch and beyond.<br />
Caption: Innovative TFT displays are key<br />
components for situation-relevant driver<br />
information and in-car infotainment systems<br />
as they allow more flexibility and new<br />
functions in the design of modern vehicle<br />
interior and safety concepts. Depending on<br />
the type of use within the vehicle – whether<br />
as an information cluster display, a central<br />
navigation and information display or as<br />
a screen rear-seat entertainment - Sharp<br />
offers TFT LCDs with wide ranging technical<br />
configurations optimized for the respective<br />
application.<br />
LCDs give great flexibility to designers<br />
with many available technologies to optimize<br />
development for different applications,<br />
examples of which are found in:<br />
• TV<br />
• e-signage<br />
• Factory automation<br />
• Automotive applications<br />
• Industrial handhelds<br />
• Mobile communication<br />
Business development in Europe<br />
Maximilian was clear that it is now<br />
time to change. With progressive market<br />
conditions, there are challenges<br />
and therefore opportunities. Emerging<br />
business areas that Sharp is targeting<br />
include:<br />
e-signage with digital, centrally operated<br />
public information<br />
LED technology where energy saving,<br />
natural colour rendering of light<br />
sources for lighting and backlight systems<br />
are paramount.<br />
Automotive displays where multifunctional<br />
interface is replacing the<br />
traditional analog pointer instruments<br />
Industrial Handhelds for decentralized<br />
process automation, for example, in<br />
the logistics and medical services areas.<br />
Summary<br />
The display market will be one of the<br />
most important growth drivers for the fu-<br />
Linear Technology<br />
ture in many market segments. Sharp has<br />
been and will continue to be a leading<br />
player in this market. Maintaining a highly<br />
successful position in this market requires<br />
a strong focus on leading edge technology<br />
in application oriented markets.<br />
Finally, the increasing awareness in<br />
the environmental and social responsibility<br />
give Sharp a competitive advantage<br />
due to its exemplary record in the<br />
approach taken in the development and<br />
manufacturing of its products.<br />
electronica: Hall A3 Stand 207, 225<br />
Hall A4 Stand 578<br />
www.sharpsme.com<br />
At its press conference in Munich, Germany recently, Linear Technology announced the LTC6802, a<br />
highly integrated multicell battery monitoring IC capable of measuring up to 12 individual battery cells.<br />
HV Battery Stack Monitor for HEVs & Battery Backup <strong>Systems</strong><br />
The proprietary design of this device<br />
allows multiple LTC6802s to be stacked<br />
in series without optocouplers or isolators,<br />
for precision voltage monitoring<br />
of every cell in long strings of seriesconnected<br />
batteries. Long battery<br />
strings enable high power, rechargeable<br />
applications, such as electric and hybrid<br />
electric vehicles, scooters, motorcycles,<br />
golf carts, wheelchairs, boats, forklifts,<br />
robotics, portable medical equipment,<br />
and uninterruptible power supply (UPS)<br />
systems.<br />
With superior energy density, Lithium-<br />
Ion batteries are poised to be the power<br />
source of choice for these applications.<br />
However, designing a large, highly<br />
Precision, High Voltage Multicell Battery<br />
Stack Monitor.<br />
Erik Soule, VP & General Manager, Signal<br />
Conditioning Products, Linear Technology.<br />
reliable and long-lasting Li-Ion battery<br />
stack is a very complex problem. Li-<br />
Ion cells are sensitive to overcharging<br />
or over-discharging, requiring that each<br />
cell in a stack is carefully managed. The<br />
LTC6802 makes this possible with quick<br />
and accurate measurements of all cell<br />
voltages, even in the presence of stack<br />
voltages over 1000V.<br />
The maximum total measurement error<br />
is guaranteed at less than 0.25% from<br />
-40°C to 85°C and all cell voltages in a<br />
battery stack can be measured within<br />
13ms. Each cell is monitored for undervoltage<br />
and overvoltage conditions,<br />
and an associated MOSFET switch<br />
is available to discharge overcharged<br />
cells. Each LTC6802 communicates via<br />
a 1MHz serial interface, and includes<br />
temperature sensor inputs, GPIO lines<br />
and a precision voltage reference.<br />
The LTC6802 was designed for the<br />
environmental and reliability challenges<br />
of automotive and industrial applications.<br />
It is fully specified for operation from -40<br />
°C to 85°C and offers diagnostics and<br />
fault detection. The LTC6802 is a small<br />
8mm x 12mm surface mount device. The<br />
combined robustness, exceptional precision<br />
and tiny package directly address<br />
the critical requirements of emerging and<br />
advanced battery technologies.<br />
“The LTC6802 provides a precision<br />
analog interface for high performance<br />
battery stacks,” said Erik Soule, Vice<br />
President & General Manager of Linear<br />
Technology’s Signal Conditioning Products.<br />
“By handling the data acquisition<br />
28 <strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
www.powersystemsdesign.com<br />
29
30<br />
ON THE ROAD<br />
task, the LTC6802 enables designers to<br />
implement state-of-the-art battery management<br />
techniques.”<br />
Priced at $9.95 each in 1,000-piece<br />
Vicor/Picor<br />
At a recent press conference, Picor, a subsidiary of Vicor Corporation, announced the Cool-ORing<br />
family of full-function Active ORing solutions and discrete Active ORing controllers. These products<br />
address the redundancy requirements in today’s high-availability systems such as servers, high-end<br />
computing and telecom and communications infrastructure systems.<br />
Picor’s Cool-ORingTM family targets redundant power<br />
architectures in high-availability systems<br />
The Cool-ORing PI2121/ PI2123/<br />
PI2125 are complete full-function Active<br />
ORing solutions with integrated highspeed<br />
ORing MOSFET controllers and<br />
very low on-state resistance MOSFETs.<br />
They address a variety of redundant bus<br />
applications, providing very low power<br />
dissipation while achieving very fast dynamic<br />
response, typically within 160ns,<br />
to system level power source fault conditions.<br />
The PI2121 is an 8V, 24A solution<br />
suitable for ≤5Vbus applications, the<br />
PI2123 is a 15V, 15A solution suitable for<br />
≤9.6Vbus applications and the PI2125 is<br />
a 30V, 12A solution suitable for 12Vbus<br />
applications.<br />
The PI2121/ PI2123/ PI2125 solutions<br />
are offered in extremely small, high density,<br />
thermally enhanced 5mm x 7mm<br />
land grid array packages, maintaining<br />
full current ratings over a wide range of<br />
operating temperature. The high level<br />
of density is enabled by integrating a<br />
very low on-state resistance MOSFET<br />
into each product. The typical on-state<br />
resistances are 1.5mOhm, 3mOhm and<br />
5.5mOhm respectively for the PI2121,<br />
PI2123 & PI2125. Each product can also<br />
be paralleled to address higher current<br />
requirements through a master/ slave<br />
feature, enabling an extremely scalable<br />
solution for a wide range of Active ORing<br />
requirements. The PI2121/ PI2123/<br />
PI2125 detect normal forward, excessive<br />
forward, light load, and reverse current<br />
flow through their internal MOSFETs,<br />
and report fault conditions via an active<br />
low fault flag output. A temperature<br />
sensing function indicates a fault if the<br />
maximum junction temperature exceeds<br />
quantities, samples, demonstration<br />
boards and the data sheet are now available<br />
at www.linear.com. The product will<br />
be available in production quantities in<br />
160°C. The under-voltage and overvoltage<br />
thresholds are programmable via<br />
external resistor dividers.<br />
The PI2001 is a discrete high-speed<br />
Active ORing controller with similar<br />
functionality and feature set, for use with<br />
industry standard single or paralleled<br />
MOSFETs.<br />
The PI2003 controller is specifically<br />
optimized for use in -48V redundant<br />
power architectures, and is suitable for<br />
systems requiring operation during input<br />
voltage transients up to 100V for 100ms.<br />
The low quiescent current of the PI2003<br />
enables simple low-loss biasing directly<br />
from the -48V rail.<br />
The Cool-ORing PI2122 is a complete<br />
full-function Active ORing solution with a<br />
circuit breaker feature, integrating a highspeed<br />
MOSFET controller and very low<br />
on-state resistance MOSFET in the high<br />
density thermally enhanced 5mm x 7mm<br />
land grid array package. It is designed for<br />
use in redundant power system architectures,<br />
suitable for ≤5 Vbus applications<br />
where added protection against load fault<br />
the fourth calendar quarter 2008.<br />
electronica: Hall A4 stand 538<br />
Hall A5 stand 568<br />
www.linear.com<br />
7V, 12A solution with integrated back-toback<br />
configured MOSFETs with an effective<br />
6mOhm typical on-state resistance<br />
enabling very high efficiency. It provides<br />
very fast dynamic response to both input<br />
power source and output load fault conditions,<br />
typically within 140ns and 170ns<br />
respectively, acting as a true bi-directional<br />
switch. In addition to responding to<br />
a reverse current fault condition, when<br />
the PI2122 detects excessive forward<br />
current, over temperature, under and<br />
over-voltage faults, it will rapidly turnoff<br />
the internal MOSFETs to provide a<br />
load disconnect feature. The PI2122 also<br />
provides a user programmable auto-retry<br />
off-time during excessive forward current<br />
fault conditions.<br />
The PI2002 is a high-speed Active<br />
ORing controller IC with a load disconnect<br />
feature that functions similar to the<br />
PI2122, but is designed for use with industry<br />
standard back-to-back N-channel<br />
MOSFETs.<br />
The Cool-ORing solutions can substantially<br />
reduce power dissipation by up<br />
to ten times versus conventional diode<br />
ORing solutions, eliminating the need for<br />
unnecessary thermal management overhead,<br />
while reducing board real estate<br />
by over 50% and maintaining benchmark<br />
dynamic response versus conventional<br />
Active ORing solutions.<br />
The discrete Cool-ORing controllers<br />
are each available in two packages:<br />
the 3mm x 3mm 10-lead TDFN and the<br />
8-lead SOIC package.<br />
conditions is required. The PI2122 is a www.vicoreurope.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
On The Right Track!<br />
Safe solutions for tough applications<br />
www.powersystemsdesign.com<br />
COVER STORY<br />
The railway traction market continuously demands space saving and improved performance for all<br />
equipment and the transducers used in such applications must follow. Standards also have increasing<br />
requirements for higher insulation and partial discharge levels in order to guarantee safety, better<br />
immunity against external electrical, magnetic and electromagnetic fields for EMC protection, low<br />
emission, excellent accuracy for example in case of energy metering application, and protection against<br />
fire and smoke mandatory in railway applications.<br />
Converters in these applications<br />
require better characteristics<br />
such as low influence in common<br />
mode, low thermal drift, fast response<br />
time, large bandwidth and low noise.<br />
LEM has introduced the first, compact,<br />
DC Class 1 accuracy voltage transducer<br />
for the traction market. LEM’s new DV<br />
technology is an innovative development<br />
using known and tested components.<br />
DV’s applications<br />
Medium and high voltage railway applications<br />
include:<br />
• Catenaries with the different voltage<br />
networks to be checked at the entrance<br />
of the locomotive (AC with different<br />
frequencies or DC catenaries voltage)<br />
• On-board energy meters needing<br />
voltage transducers to feed their voltage<br />
input channels designed to receive any<br />
traction network. Typically, they are located<br />
at the circuit breaker level, where<br />
high accuracy is required, even at lower<br />
voltage.<br />
• Substations where voltage transducers<br />
monitor the DC voltages supplied to<br />
the catenaries at the DC rectifier output.<br />
LEM’s new technology DV transducer<br />
is aimed at R&D engineers within<br />
the railway industry (main converters<br />
and sub-stations) and medium voltage<br />
industrial applications. Target applications<br />
include measurement of network<br />
By Michel Ghilardi and Marc Schaerrer, LEM SA<br />
voltages and in the DC link of the main<br />
converters on trains. Mainly designed<br />
for on-board railway applications like<br />
traction or auxiliary converter, the DV<br />
transducer can also be adapted to any<br />
kind of other aggressive environment<br />
requiring high performance, reduced<br />
volume and reliability.<br />
The DV’s high insulation level is<br />
achieved by a LEM robust and proven<br />
technology. It is significantly smaller<br />
than any equivalent product on the market<br />
today, measuring only 134 x 54.22<br />
x 147.25mm (1069cc) and is only half<br />
the size and weight of the earlier LEM<br />
LV 200-AW/2/Voltage transducer which<br />
uses closed loop Hall effect technology<br />
on the same footprint. The DV models<br />
are 100% compatible with the earlier<br />
LEM LV 200-AW/2/Voltage and CV<br />
4-Voltage models within the same footprint<br />
mounting. This is desirable when<br />
retrofits are required on older installations.<br />
The large volume needed by the former<br />
closed loop Hall effect and Fluxgate<br />
technologies can be attributed to the<br />
magnetic circuits necessary for operation.<br />
The advantage of the electronicbased<br />
DV technology is to minimize the<br />
31
Four-Day<br />
<strong>Power</strong> Supply<br />
<strong>Design</strong> Workshop<br />
Bordeaux, France at the Mercure Hotel March 30 - April 2, 2009<br />
Learn first-hand from Dr. Ray Ridley, a leading power electronics industry<br />
consultant and researcher. During his 28 years in the industry, he has taught<br />
advanced design to thousands of engineers worldwide.The world’s<br />
leading engineering companies in aerospace, semiconductors and<br />
commercial applications send their engineers to the Workshop<br />
to take their designs to the next level.<br />
The Workshop focuses on theoretical and practical concepts<br />
with hands-on experience. Learn to design, build and<br />
measure switching power supplies in our<br />
state-of-the-art travelling laboratory.<br />
Study theory and design concepts each<br />
morning, and build circuits and magnetics in the<br />
afternoon. Learn how to use POWER 4-5-6,<br />
the world’s most comprehensive design<br />
software and receive your own<br />
personalized copy for attending<br />
the workshop.<br />
Tuition is €2500 and includes training, lab<br />
notes, POWER 4-5-6 software and lunch.<br />
Reservations are now being accepted.<br />
Only 24 seats are available at each workshop.<br />
Download a registration form at www.ridleyengineering.com<br />
Agenda<br />
Monday Morning Lecture 8:30 - 12:00<br />
<strong>Power</strong> Stage Topologies<br />
Inductor <strong>Design</strong><br />
Saturation<br />
Core Loss<br />
Proximity Loss<br />
Practical <strong>Design</strong> Procedures<br />
Tuesday<br />
Wednesday<br />
Thursday<br />
Morning Lecture 8:30 - 12:00<br />
Transformer <strong>Design</strong><br />
Saturation<br />
Leakage Inductance<br />
Planar Magnetics<br />
Proximity Loss<br />
Multiple Output Cross-Regulation<br />
Winding Capacitance<br />
Practical <strong>Design</strong> Procedures<br />
Gate Drive and Current-Sense Transformers<br />
Morning Lecture 8:30 - 12:00<br />
Simulation of <strong>Power</strong> Supplies<br />
Small-Signal Analysis for Voltage-Mode Control<br />
PWM Switch Model<br />
CCM and DCM Operation<br />
Right-Half-Plane Zeros<br />
Loop Gain Criteria<br />
Compensation <strong>Design</strong><br />
Morning Lecture 8:00 - 11:00<br />
Current-Mode Control<br />
Current-Mode Circuit Implementation<br />
Current-Mode Problems<br />
Current-Mode Advantages<br />
Small-signal Analysis of Current-Mode Control<br />
Subharmonic Oscillation<br />
Current-Mode Feedback <strong>Design</strong><br />
WWW.RIDLEYENGINEERING.COM<br />
Afternoon Laboratory 13:00 - 17:00<br />
<strong>Design</strong> of Flyback Inductor/Transformer<br />
Construction, Winding, Gapping Transformer<br />
Impedance and Leakage Measurement<br />
In-Circuit Testing<br />
Snubber <strong>Design</strong><br />
Full <strong>Power</strong> Testing<br />
Efficiency Measurements<br />
Afternoon Laboratory 13:00 - 17:00<br />
<strong>Design</strong> of Forward Inductor<br />
<strong>Design</strong> of Forward Transformer<br />
Construction, Winding, Gapping Forward Mag.<br />
Impedance and Leakage Measurement<br />
In-Circuit Testing<br />
Snubber <strong>Design</strong><br />
Full <strong>Power</strong> Testing and Efficiency Measurements<br />
Afternoon Laboratory 13:00 - 17:00<br />
Measurement of Forward Control Characteristics<br />
Output Impedance Measurement<br />
Control Loop Compensation<br />
Loop Gain Measurement<br />
Stability Optimization<br />
Step-Load Response Measurement<br />
Afternoon Laboratory 12:00 - 15:30<br />
Measurement of Flyback with Current-Mode<br />
Compensating Ramp Addition<br />
Control Loop Compensation<br />
Loop Gain Measurement<br />
Stability Optimization<br />
Second-Stage Filter <strong>Design</strong><br />
SARL Ridley Engineering Europe ~ Chemin de la Poterne ~ Monpazier 24540 ~ FR ~ +33 (0)5 53 27 87 20 ~ Fax: +33 (0)5 67 69 97 28<br />
Ridley Engineering UK Ltd. ~ 10 The Green ~ Bracknell, Berkshire RG12 7BG ~ UK ~ +44 (0)1344 482 493 ~ Fax: +44 (0)1344 204 632<br />
Ridley Engineering, Inc. ~ 885 Woodstock Rd., Suite 430-382 ~ Roswell, GA 30075 ~ US ~ +1 770 640 9024 ~ Fax: +1 770 640 8714<br />
Email: DRidley@ridleyengineering.com
34<br />
COVER STORY<br />
LEM’s new DV voltage transducer<br />
magnetic circuit providing the isolation<br />
and to integrate only electronic components<br />
(amplifiers, resistors, capacitors,<br />
A/D and D/A converters, micro-controllers,<br />
etc.) The large heatsinks usually<br />
installed on Hall effect and Fluxgatebased<br />
voltage transducers have been<br />
removed by reducing losses.<br />
With electrical drives for railway locomotives<br />
supplied from networks up to<br />
3kV, the measurement signal needs to<br />
be transmitted to electronic circuits at<br />
low voltage for control and/or display<br />
purposes. The transmission of power<br />
and signals between a high voltage en-<br />
vironment to a low voltage environment<br />
requires specific insulation features.<br />
DV’s description<br />
To achieve this, LEM has designed a<br />
new range of voltage transducers based<br />
on a new patented technology which is<br />
different to the traditionally used closed<br />
loop Hall effect technology. The result is<br />
the DV series voltage transducers that<br />
cover nominal voltage measurements<br />
up to 4200 VRMS. To operate, they only<br />
need to be connected to the measuring<br />
voltage, without inserting additional<br />
resistors on the primary side, and a<br />
standard DC power supply range of ±<br />
13.5V to ±26.4 V.<br />
With a primary voltage higher than<br />
zero, the transducer consumes a<br />
maximum of 23mA (maximum internal<br />
consumption), plus the output current<br />
(typically 50mA at nominal value), when<br />
programmed with current output.<br />
In comparison to the other methods<br />
used to measure high voltages, this<br />
provides considerable energy savings<br />
on customer supply - for example, a<br />
Fluxgate based voltage transducer<br />
consumes between 35-50mA with no<br />
primary voltage.<br />
Based on LEM’s long experience in<br />
current and voltage transducers for traction<br />
application, the DV covers customer<br />
requirements for nominal voltage<br />
measurement to 4.2kV RMS. It features<br />
a combination of all the advantages of<br />
previous LEM products and fulfilment of<br />
all new EMC requirements. This product<br />
has been developed according to IRIS<br />
standards:<br />
• Low consumption of about 19-23mA<br />
• Frequency bandwidth 12kHz<br />
• Safety insulation 18.5 kV<br />
This is followed by a digital encoder<br />
producing a single serial signal enabling<br />
data to be transmitted via one single,<br />
isolated channel. Thereafter, an amplifier<br />
feeds the signal to the primary side<br />
transformer, transformer required to<br />
Figures 1: Starting from the left of the diagram at the primary side, where input voltage might typically be ±4.2kV, the first<br />
stage is a voltage divider that reduces the supply down to a few volts, and is able to withstand high dv/dt while having low<br />
thermal drift. Then a sigma delta modulator converts the signal from analogue to digital as a 16-bit output.<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
provide the desired galvanic isolation.<br />
Due to the high voltage environment, a<br />
double core transformer is considered,<br />
limited in size thanks to the considered<br />
high digital working frequency. Windings<br />
are wound into a PCB, similar in layout<br />
to a planar transformer, which affords<br />
product repeatability and assures component<br />
behaviour.<br />
The product is primarily designed for<br />
onboard traction and stationary traction<br />
substation applications. Within a<br />
substation the insulation test voltage is<br />
above 18kV for one minute for a working<br />
voltage of 4.2kV, while onboard, the<br />
insulation test voltage is max 13kV.<br />
The transformer therefore needs to<br />
withstand such a high test voltage,<br />
while at the same time the lifetime of the<br />
insulation can be guarantee by a partial<br />
discharge test, where a voltage is applied<br />
between the primary and secondary<br />
to determine if there is a discharge,<br />
which should measure less than 10 Pico<br />
coulombs.<br />
On the secondary side the bit-stream<br />
is decoded and filtered by a digital filter.<br />
Because the primary signal square wave<br />
is distorted by the transformer, there is<br />
a Schmitt trigger on the secondary side<br />
of the transformer to restore it to square<br />
wave. This is then fed into a decoder<br />
and digital filter, the function of which<br />
is to decode the data bit stream into a<br />
standard digital value that can be used<br />
in digital to analogue conversion within<br />
the microcontroller. The recovered<br />
output signal is completely insulated<br />
against the primary (high voltage), and<br />
is an exact representation of the primary<br />
voltage.<br />
The transducer can be easily adapted<br />
for different ranges by modifying the<br />
gain programmed by the microcontroller.<br />
This does not require changes in the design<br />
of the transformer or in the design<br />
of the assembly of the circuit boards in<br />
the housing. The microcontroller cancels<br />
offsets and adjusts the gain by software,<br />
and then converts the signal from digital<br />
to analogue output. The micro-controller<br />
transfers data from the digital filter to a<br />
12-bit D/A converter with a transfer time<br />
of around 6 μs. The analogue output<br />
voltage is then filtered and converted<br />
into a current (75mA full scale) using<br />
www.powersystemsdesign.com<br />
a current generator protected against<br />
short-circuits.<br />
The microcontroller also regulates a<br />
DC/DC converter that creates internal<br />
secondary regulated supply voltages<br />
supplied by customer DC supply which<br />
will typically be ±24V or ±15V, while<br />
also supplying ±5V and ±3.3V to the<br />
primary side sigma delta converter and<br />
digital encoder. The additional circuitry<br />
is shown as a group at the top of the<br />
circuit schematic, with the frequency<br />
of the DC to DC converter given by the<br />
microcontroller.<br />
The last block to the right of the<br />
microcontroller is a voltage to current<br />
converter for customers who prefer current<br />
output, typically 50mA, in order to<br />
comply with electromagnetic compatibility<br />
(EMC) regulations. The lower impedance<br />
current output is less prone to<br />
interference from external electromagnetic<br />
fields. A voltage output version<br />
to 10V is also available, for example,<br />
where the transducer is to be used with<br />
shielded cable or with short connections<br />
to customer electronics.<br />
Main characteristics<br />
Providing excellent overall accuracy<br />
with ±0.3% of VPN at ambient temperature<br />
and over its operating temperature<br />
range from -40°C to 85°C, the DV shows<br />
a low temperature drift resulting in an<br />
overall accuracy of only ±1 % of VPN.<br />
Initial offset at 25°C is 50μA max with a<br />
maximum possible drift of ±100μA over<br />
the operating temperature range. Sensitivity<br />
error at 25°C is ±0.2%. The microcontroller,<br />
used among other things for<br />
D/A conversion, is also useful for offset<br />
and gain adjustment during production,<br />
enabling these parameters. Linearity is<br />
only ±0.1%.<br />
The DV transducer’s typical response<br />
time (defined at 90% of VPN) against a<br />
voltage step at VPN has a delay of 48μs<br />
(Max 60µs). Other closed Loop based<br />
on Hall effect voltage transducers have<br />
a response delay of several hundred<br />
microseconds. As a result of the fast<br />
response time, a large bandwidth has<br />
been verified at 12kHz at -3 db (Fig. 3).<br />
Mechanical and standards<br />
The DV’s modular approach allows<br />
easy adaptation with various connec-<br />
COVER STORY<br />
tions available for the primary side, e.g.<br />
terminals or isolated cable, and any kind<br />
of connection for the secondary side like<br />
connectors, shielded cables, terminals<br />
(threaded studs, M4, M5, UNC etc.) according<br />
to customer specifications.<br />
The DV models have been designed<br />
and tested according to latest recognised<br />
worldwide standards for traction<br />
applications. The EN 50155 standard<br />
“Electronic Equipment used on Rolling<br />
stock” in railway applications is the<br />
standard of reference for electrical, environmental<br />
and mechanical parameters.<br />
It guarantees the overall performances<br />
of products in railway environments.<br />
LEM’s main production centres for<br />
traction transducers are IRIS certified -<br />
essential for companies supplying the<br />
railway market. DV transducers are CE<br />
marked as a guarantee of compliance<br />
to the European EMC directive 89/336/<br />
EEC and low voltage directive. They<br />
also comply with the derived local EMC<br />
regulations and with the EN 50121-3-2<br />
standard (railway EMC standard) in its<br />
latest update, with EMC constraints<br />
higher than that of the typical industrial<br />
application standards.<br />
The EN 50124-1 “Basic requirements<br />
- clearances and creepage distances for<br />
all electrical and electronic equipment”<br />
standard has been used as a reference<br />
to design the creepage and clearance<br />
distances for the DV transducers versus<br />
the required insulation levels (rated<br />
insulation voltage) and the conditions of<br />
use. Clearance is the shortest distance<br />
in air between two conductive parts and<br />
creepage is the shortest distance along<br />
the surface of the insulating material<br />
between two conductive parts. Pollution<br />
degree is application specific and is a<br />
way to classify the micro-environmental<br />
conditions having an effect on the insulation.<br />
Overvoltage category is also application<br />
specific and characterises the<br />
exposure of the equipment to overvoltage.<br />
Partial discharge (PD) is the dissipation<br />
of energy caused by the buildup<br />
of localised electric field intensity.<br />
Electric discharges partially bridge the<br />
insulation. Failure is by gradual erosion<br />
or ‘insulation, leading to puncture or<br />
surface flashover. The partial discharge<br />
35
36<br />
COVER STORY<br />
Figures 2&3: show the transformer response time and frequency bandwidth respectively, and in the case of energy measurement,<br />
phase is as important as amplitude, because you can get phase shift even at frequencies below 1kHz, and what<br />
is important for traction customers is measurement without delay.<br />
test verifies that no partial discharges<br />
are maintained in the solid insulation at<br />
the highest steady-state voltage, at the<br />
long-term repetitive voltage.<br />
The higher the extinction partial discharges<br />
voltage (> 5kV) is the better, as<br />
no discharges happen during the normal<br />
defined function. The partial discharges<br />
level is defined at 10 pC.<br />
Accelerated tests have been performed<br />
to estimate failure rate including<br />
temperature cycles and complete char-<br />
acterisation of the product according<br />
to standards. Thanks to an innovative<br />
design using the insulation transformer,<br />
the DV models guarantee insulation and<br />
PD levels for high voltage applications<br />
up to 5kV peak.<br />
In the past the commutations of the<br />
semiconductors were slow, which implied<br />
low dv/dt). Now new technologies<br />
like IGBT and MOSFETs provide higher<br />
dv/dt between primary and secondary.<br />
The secondary is generally connected to<br />
ground for safety reasons. The primary<br />
Figuer 4: Due to the DV’s low parasitic capacitance, the effect of dynamic common<br />
mode is reduced.<br />
is the measurement of differential voltage,<br />
but voltage can float. The potential<br />
change on the primary will cause<br />
a perturbation at the secondary. This<br />
cannot be filtered because it will reduce<br />
response time, so the parasitic capacitance<br />
between primary and secondary<br />
has to be reduced in the design.<br />
Mainly designed for medium and high<br />
voltages on-board railway applications<br />
like propulsion or auxiliary converter,<br />
DV transducers are also suitable for any<br />
kind of rugged environments, requiring<br />
good performance in terms of accuracy,<br />
gain, linearity, low initial offset, low thermal<br />
drift, etc. Featuring high immunity to<br />
external interferences, generated by adjacent<br />
currents or external perturbations<br />
for example, and high immunity against<br />
high voltage variations, DV transducers<br />
offer excellent reliability. The DV is the<br />
first DC class 1 accuracy voltage transducer<br />
on the market providing outstanding<br />
performance over a large voltage<br />
and temperature range. It can also be<br />
used for energy monitoring and billing<br />
purposes.<br />
www.lem.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
In the larger-scale PV system shown<br />
in Figure 8 below, several inverters<br />
are combined in multiple racks for a<br />
total output power of 500kW. One of the<br />
inverters is pulled out of the rack, demonstrating<br />
the easy replacement. The<br />
unit in the middle is the monitoring unit,<br />
used to control all inverters and monitor<br />
the performance of the subsections<br />
www.powersystemsdesign.com<br />
Solar <strong>Power</strong> Shines!<br />
of the solar power plant. There are also<br />
systems that can handle up to 200kW<br />
in one (larger) rack unit, at increased<br />
power density.<br />
As shown above, the front end of the<br />
inverter has a distinct task. In order for<br />
the back end to perform the DC-to-AC<br />
conversion with high efficiency, it is best<br />
to “feed” it with a DC voltage that is by<br />
a certain margin higher than the maximum<br />
required output voltage, so that<br />
the backend only needs to perform a<br />
step-down function. But the output voltage<br />
of one panel is typically 50 to 80V,<br />
so several panels must be connected in<br />
a series to achieve a high input voltage.<br />
And, the voltage will depend on the<br />
solar radiation density – very quickly,<br />
a pretty complex situation is achieved.<br />
The challenges are:<br />
Solar <strong>Power</strong><br />
Implications of solar panel technologies and<br />
system power ranges<br />
Here, we continue (See September 2008 PSDE, page 38) with the technology of harnessing solar<br />
energy that is re-shaping the energy generation scene and is having a dramatic effect on the way<br />
semiconductors can be applied to solve the problems of environmental pollution and the escalating<br />
cost of conventional sources.<br />
By Alfred Hesener, Director for Applications and Marketing, Fairchild Semiconductor, Europe<br />
Figure 8: Rack with several higherpower<br />
inverters working in parallel.<br />
Part II<br />
• The input voltage can vary over a<br />
wide range. If the number of panels<br />
chosen and connected in series is so<br />
high that the input voltage is higher<br />
than the output voltage under all<br />
conditions, then the maximum input<br />
voltage is so high that power switches<br />
with very high breakdown voltages<br />
are needed (which is expensive and<br />
lowers efficiency), and the handling<br />
and cabling is more difficult (making<br />
the system less reliable). A compromise<br />
is to choose a smaller number<br />
of panels in series, so that the voltage<br />
cannot become so high, but in order to<br />
provide output power at lower radiation<br />
levels a boost converter is needed.<br />
The total efficiency and the yield of the<br />
system can be shown to actually be<br />
higher, even though the system is more<br />
complex.<br />
37
38<br />
Solar <strong>Power</strong><br />
Figure 9: MPP tracker (Source: Photon).<br />
• In a larger system, several strings of<br />
series-connected panels are connected<br />
to an inverter. If one of the panels is<br />
shaded or the cells have a lower yield<br />
to begin with, the output voltage of<br />
this string will be lower. In order for<br />
this string to contribute to the output,<br />
individual boost converters are used for<br />
each string, compensating individual<br />
variations, and operating each string in<br />
its maximum power point.<br />
• As individual panels have different<br />
MPPs, they must be sorted before connecting<br />
them together, to ensure their<br />
MPPs match, or even the best inverter<br />
in the world will not be able to maximize<br />
the yield.<br />
The MPP tracking function requires a<br />
multiplication of the voltage and current,<br />
to calculate the output power. Then,<br />
the load impedance is varied slightly,<br />
and the system moves in the direction<br />
of higher power drawn from the panels.<br />
This algorithm is then repeated. As the<br />
radiation usually changes slowly, a high<br />
speed loop is not required.<br />
Figure 9 shows an example of the<br />
MPP tracker matching at the input,<br />
that means, how close the front end<br />
converter is able to match its input<br />
impedance to the output impedance of<br />
the panels. The horizontal scale is the<br />
nominal power; the vertical scale the<br />
input voltage. Higher efficiency areas<br />
are shaded in red. The input impedance<br />
is controlled within the feedback loop<br />
of the MPP tracker, so any deviation is<br />
signaled through a lower efficiency and<br />
implies something this control loop cannot<br />
regulate away – an implicit limitation<br />
of the inverter, and the topologies<br />
and components chosen. Another root<br />
cause can be measurement errors in<br />
determining the input current and<br />
voltage, as well as limitations in the<br />
resolution of the A-to-D converters<br />
and controllers.<br />
Figure 10 shows the total conversion<br />
yield of the same inverter, disregarding<br />
the mismatch at the input,<br />
but looking purely at the AC output<br />
power versus the DC input power.<br />
The horizontal scale is the nominal<br />
power, and the vertical scale shows<br />
the input voltage. This example<br />
shows an inverter that actually works<br />
quite well, particularly with high input<br />
voltages, but as the voltage drops the<br />
yield also goes down. On the left hand<br />
side the inherent energy consumption of<br />
the inverter can be seen to reduce the<br />
yield. The input overcurrent protection<br />
can be seen in the lower right corner.<br />
As can be seen from the diagram,<br />
the “harder” the front end converter<br />
needs to work, the lower the yield. At<br />
high input voltages, very little additional<br />
boost needs to be provided, so the corresponding<br />
power dissipation is lower.<br />
However, at lower input voltages, a high<br />
AC current ripple in the input translates<br />
to larger losses. Improvements in the<br />
boost converter would first of all improve<br />
the overall efficiency, and secondly,<br />
move the area of maximum efficiency<br />
to lower input voltages, providing a<br />
better match to the panels. As panels<br />
do have a non-zero source resistance,<br />
the output voltage under load can be<br />
significantly lower than the no-load voltage,<br />
particularly for thin-film panels. So,<br />
this reduced voltage level is where the<br />
maximum yield of<br />
the inverter should<br />
be and not at very<br />
high input voltages<br />
as the yield will be<br />
wasted with this<br />
mismatch.<br />
It is interesting<br />
to note that<br />
the best tracking<br />
is achieved at an<br />
input voltage of<br />
390V, precisely the<br />
voltage chosen at<br />
design to turn-off<br />
the boost converter,<br />
and a clear<br />
distinction can be<br />
seen at the handover point between the<br />
two-stage and the single-stage operating<br />
mode. The inefficiencies in the tracking<br />
as well as power conversion are due<br />
to a sub-optimal inverter that cannot<br />
transform a required input impedance<br />
value well enough to a certain output<br />
impedance. In the upper left hand corner,<br />
a lower tracking and also efficiency<br />
is visible, indicating the main inverter<br />
cannot handle low input currents at high<br />
voltages very well. This may be caused<br />
by power switches with too high output<br />
capacitances, as the losses are proportional<br />
to C*U 2 . As the current in the inverter<br />
increases (moving in the diagram<br />
to the right), the proportion of switching<br />
losses is getting smaller compared to<br />
the conduction losses, so the efficiency<br />
actually improves, although the power<br />
dissipation goes up.<br />
As can be seen on the left hand side<br />
with the vertical yellow areas in Figure<br />
10, the yield is lower at low power, probably<br />
due to this inverter having higher<br />
than necessary switching losses in the<br />
boost converters. At the lower right<br />
corner, at a combination of low input<br />
voltage and high power, the input current<br />
becomes very large so the input DC<br />
over current protection will switch off<br />
the inverter. On the right hand side, at<br />
power levels over 115%, the inverter will<br />
turn off as well.<br />
In order to improve the performance,<br />
and have larger parts of the diagram<br />
“red”, various measures can be implemented.<br />
Apart from the obvious optimization<br />
in passive components, the boost<br />
Figure 10: Total conversion yield (Source: Photon).<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
Figure 11: The correct gate drive of the power switches is crucial in many respects.<br />
diodes need to be carefully selected<br />
for low switching losses (improving the<br />
performance at low input power, the left<br />
side of the diagram), and for low forward<br />
voltage drop (to improve the yield at<br />
high input currents, the lower part of<br />
the diagram). The StealthTM II diodes<br />
from Fairchild Semiconductor or silicon<br />
carbide diodes can provide this optimization.<br />
The power switches in the boost<br />
converter, usually MOSFETs, also need<br />
to be carefully chosen. At low input voltages,<br />
the current through the switches<br />
is causing conduction losses due to<br />
the high duty cycle, so low RDSON is<br />
important – in fact, it is not uncommon<br />
to see several large MOSFETs in TO-247<br />
packages connected in parallel.<br />
Further improvements can be gained<br />
with a careful choice of operating<br />
mode of the boost converter. Continuous<br />
mode conversion is chosen,<br />
to minimize AC losses, and the lower<br />
ripple currents allow for reduction of<br />
unwanted overhead in the system.<br />
However, this is a hard-switching<br />
system, so power MOSFETs with a<br />
low output capacitance should be<br />
chosen. This however contradicts<br />
somewhat with the requirement for low<br />
conduction losses in the switch, to be<br />
obtained with a larger device. Here,<br />
a good compromise can be found in<br />
Fairchild’s SuperFET devices that<br />
can at the same time provide a “fast”<br />
body diode at no RDSON penalty.<br />
This also helps at the lower right hand<br />
corner of the diagram, as at low input<br />
voltage and high power the duty cycle<br />
of the converter is quite long, with high<br />
www.powersystemsdesign.com<br />
currents in the switch.<br />
The value of Rgate plays a significant<br />
role in the performance of the system.<br />
The lower this resistor becomes, the<br />
faster the MOSFET will be switching<br />
(provided the gate driver has sufficiently<br />
low output impedance). Faster switching<br />
corresponds to higher dI/dt and dv/dt,<br />
increased electromagnetic emission<br />
(EMI), and can lead to breakdown of<br />
the components, reducing reliability. If<br />
the gate resistor value is increased, the<br />
switching speed is reduced, but this<br />
means the overlap between current in<br />
the device, and voltage across the device,<br />
is increased, and so are the switching<br />
losses. In other words, the switch<br />
behaves less and less as a switch, but<br />
spends more and more time in the linear<br />
region, causing power dissipation. In<br />
conclusion, the gate resistance values<br />
need to be finely tuned for lowest power<br />
dissipation and EMI.<br />
To improve performance even further,<br />
resonant or quasi-resonant topologies<br />
can be used, although they can be challenging<br />
to implement for a wide input<br />
voltage range and still operate at ZVS<br />
(“zero voltage switching”) or ZCS (“zero<br />
current switching”). Another topology to<br />
improve performance is the interleaved<br />
boost converter. Here, multiple converters<br />
are working in parallel, out-of-phase<br />
with each other, and it can be shown<br />
that the ripple current in the output can<br />
be reduced. And, if the input voltage is<br />
high enough, the boost converter can be<br />
turned off completely and bridged e.g.,<br />
with a relay, to further reduce losses.<br />
Solar <strong>Power</strong><br />
The inverter or DC-to-AC section of<br />
the inverter can be built with many different<br />
topologies, quite a few of them<br />
proprietary to some of the companies<br />
building inverters. One of the “classical”<br />
topologies consists of using a<br />
full bridge, driving output inductors to<br />
reduce EMI. Here, some of the devices<br />
can be switched at line frequency<br />
whereas others are switched with the<br />
conversion frequency – if done cleverly,<br />
the first devices can be chosen<br />
for lowest conduction losses, like the<br />
Non Punch Through(NPT) Fieldstop(FS)<br />
IGBTs from Fairchild Semiconductor,<br />
whereas the latter should be chosen for<br />
lowest switching losses, e.g. the new<br />
NPT Field Stop Trench devices from<br />
Fairchild Semiconductor. Here, a combination<br />
of different IGBTs or even IGBTs<br />
and MOSFETs can help to improve the<br />
overall yield. And to properly drive the<br />
power switches, optically isolated gate<br />
drivers like Fairchild’s FOD3180 can be<br />
used, improving the system reliability<br />
where high dv/dt can suddenly occur,<br />
e.g., in the case of a grid fault.<br />
In applications such as solar inverters,<br />
where the key performance parameter<br />
is the conversion efficiency, improvements<br />
in switching device performance,<br />
through the use of IGBTs, MOSFETs<br />
and diodes are very important. Here,<br />
the voltage drops and switching energy<br />
losses can still be improved, although in<br />
order to realize the potential gains, more<br />
brainpower has to go into how to drive<br />
the switches properly, to avoid parasitic<br />
oscillations and overvoltages: the two<br />
biggest enemies of high efficiency and<br />
robustness. Here, integration of subsystems<br />
into intelligent power modules can<br />
really help! Due to the close proximity<br />
and ideal matching of driver and power<br />
switch, the best possible switching<br />
behavior can be realized repeatedly.<br />
Fairchild Semiconductor is driving the<br />
state-of- the-art in both power switch<br />
technologies as well as module integration<br />
to support further performance<br />
improvements in these green high-tech<br />
applications.<br />
www.fairchildsemi.com<br />
39
Avoiding Current Spikes<br />
The relationship between voltage<br />
and current is similar to the relationship<br />
between water pressure<br />
and water flow. Higher water pressure<br />
represents higher voltage and higher<br />
water flow represents higher current.<br />
One can observe flow or pressure, both<br />
or neither, depending on the system<br />
under consideration. For example, when<br />
compared to a standard garden hose,<br />
a fire hose has high pressure and high<br />
flow. Contrast this to the Amazon River<br />
which has a much higher flow and lower<br />
pressure. An example of high pressure<br />
and no flow is the water behind a dam.<br />
The dam acts like an open switch in an<br />
electronic circuit storing water (voltage)<br />
for immediate release.<br />
To fully understand the difference<br />
between incandescent bulbs and<br />
semiconductors such as LEDs, let us<br />
consider voltage driven devices for a<br />
minute. The filament of an incandescent<br />
bulb is simply a resistor. When electrically<br />
powered, the filament heats to near<br />
white hot temperature - more than<br />
5,800°F or 3,250°C. The high temperature<br />
of the filament generates the light.<br />
When first powered, the filament is cold<br />
and has a much lower resistance than<br />
when it is hot. According to<br />
Ohm’s law, V = I R, the current in the<br />
filament is higher when the bulb is first<br />
turned and the filament is cold. This cur-<br />
www.powersystemsdesign.com<br />
with LEDs<br />
rent is known as the “in-rush” current.<br />
Very quickly after turn-on, the filament<br />
heats to its operating temperature. As<br />
the filament heats, the resistance goes<br />
up dramatically and the current drops<br />
proportionately. In much less than a<br />
second, the filament resistance stabilizes<br />
and the current is constant.<br />
Due to the characteristics of filaments,<br />
driver designs for bulbs expect<br />
an in-rush current as part of their<br />
performance. As long as the voltage is<br />
constant, bulbs tolerate these current<br />
fluctuations. However, bulbs are very<br />
sensitive to voltage variations. Different<br />
sources cite different levels of sensitivity,<br />
a recent check of Wikipedia stated<br />
the lifetime of a bulb was dependant on<br />
the inverse of the sixteenth power of the<br />
voltage. In other words, an increase in<br />
voltage of only 5% could have a dramatic<br />
effect on the lifetime of the bulb.<br />
Using the equation:<br />
Lifetime bulb = (105% V rated / 100% V rated) -16<br />
(representing a 5% increase in Voltage)<br />
Lighting<br />
Hot switching can destroy any LED.<br />
Well designed drivers are the simple solution<br />
Unlike many illumination sources, such as incandescent bulbs that are voltage driven, LEDs are current<br />
driven devices. This distinction requires different considerations when designing and using driver<br />
electronics. Here, we compare incandescent bulbs to LEDs to highlight this subtle difference.<br />
By Pat Goodman, Technical Director, Philips Lumileds, San Jose, California<br />
Figure 1: Typical switched circuit.<br />
Lifetime bulb = (1.05) -16<br />
Lifetime bulb = 45.8% of initial lifetime<br />
Simply stated, a 5% increase in voltage<br />
decreases the bulb lifetime by more<br />
than half. Therefore, for a robust product<br />
performance, incandescent bulbs depend<br />
on well-regulated voltages while<br />
being tolerant to some current fluctuations.<br />
LEDs are current-sensitive devices.<br />
However, although slight changes in<br />
current, such as the 5% mentioned<br />
above, do not affect LEDs nearly as<br />
much as similar changes in voltage affect<br />
filaments in bulbs, it is still important<br />
that designers consider transient<br />
peak currents when implementing LED<br />
driver circuits. Specifically, there are a<br />
few areas where switching on the LED<br />
causes current spikes that exceed the<br />
circuit design current by many times.<br />
Fortunately, “forewarned is fore-armed”<br />
as they say, and some simple considerations<br />
eliminate occurrences of these<br />
current spikes.<br />
41
42<br />
Lighting<br />
Figure 2: Hot switching performance<br />
The terms “Hot Switching” and “Hot<br />
Plugging” refer to the act of inserting a<br />
device (mechanically or electrically) into<br />
a powered electronic circuit. An example<br />
of “Hot Plugging” is turning on the<br />
socket before screwing in a bulb. When<br />
inserting the bulb into the socket, it<br />
lights immediately upon contact with the<br />
bottom of the socket. This is because<br />
there was energy in the metal contacts<br />
in the socket. A similar effect occurs<br />
when connecting a semiconductor, from<br />
high-end computer chips to LEDs, to a<br />
hot circuit. However, in the semiconductor<br />
case, this “hot-switch” can result in<br />
an in-rush current that can damage the<br />
device.<br />
Going back to water example, imagine<br />
the water in a hose connected to your<br />
house. With the faucet on but the nozzle<br />
closed, the pressure in the hose is at<br />
a maximum. When first opening the nozzle,<br />
this water pressure surges though<br />
the small opening until the flow drops<br />
to the amount regulated by the nozzle.<br />
Everyone has probably seen the “spurt”<br />
of water when first opening a nozzle.<br />
The time it takes for the flow to drop<br />
to the regulated level is sufficiently fast<br />
that most of us do not care about the<br />
“spurt” (although it’s great if you need<br />
that little extra distance in water fight!).<br />
Similarly, with electrical circuits, the time<br />
it takes for a current to regulate is too<br />
fast for us to notice. In fact, we usually<br />
want things to turn on immediately.<br />
However, semiconductors react millions<br />
of times faster than humans do. A very<br />
short current pulse – sometimes just a<br />
few milliseconds long – can destroy a<br />
semiconductor chip.<br />
One might ask the question “How<br />
much power is stored in a simple<br />
switched circuit?” The easy answer is<br />
“A Lot”, enough to cause damage to the<br />
semiconductor. The full answer takes<br />
a little more explanation. To clearly<br />
demonstrate the effect, let us consider<br />
a simple circuit consisting of a current<br />
source driver, a switch, and a string of<br />
n LEDs wired in series (figure 1). In this<br />
example, assume the maximum V f of<br />
the LED string is 36V. The driver specifications<br />
include forward current (If) =<br />
Figure 3: Soft start example.<br />
350mA at a 50V maximum, similar to a<br />
typical 25W supply.<br />
The circuit controls the current to<br />
350mA when the switch is closed.<br />
However, when the switch is open, the<br />
current flow stops and the circuit is unable<br />
to regulate itself. In a short time,<br />
the voltage between the output of the<br />
power supply (PS) rises to the compliance<br />
voltage shown on the specification<br />
sheet or +50V. This is easily proven<br />
by measuring the voltage between the<br />
power supply terminals with a voltmeter.<br />
Remembering our water example, there<br />
is stored charge in the system similar to<br />
stored water in pipes. The output of the<br />
power supply, and the wires, act like a<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
very large capacitor by storing charge<br />
analogous to the manner pipes and the<br />
hose store water. When the switch is<br />
closed, this charge flows rapidly through<br />
the circuit until the power supply begins<br />
to self-regulate. However, the total<br />
stored charge in the wires may be sufficient<br />
to destroy a semiconductor such<br />
as an LED.<br />
Preventing the destructive current<br />
surge is a matter of design. The simple<br />
statement of “No Hot Switching”, “Soft<br />
Start”, or “Cold Switched” is sufficient<br />
to assure no current surge. To a lay person<br />
the difference between the surging<br />
current of a hot-switched unit and a unit<br />
with a soft start is best seen in a chart.<br />
The chart plots current (on the left y-axis)<br />
and voltage (on the right axis) versus<br />
time. There are three points of interest:<br />
before the device is switched on; during<br />
the time it takes the power supply to<br />
regulate (usually a few milliseconds);<br />
and, after the current regulates.<br />
By using Ohm’s Law, where the Volt-<br />
<strong>Power</strong>Pack <strong>Power</strong>Pack<br />
www.powersystemsdesign.com<br />
age is equal to the current multiplied by<br />
the resistance or V = IR, we can calculate<br />
Current through the LED. From the<br />
graph, it is easy to see how the voltage<br />
transient behavior injects a large current<br />
spike (in this case, three times the design<br />
value) into the LED. These current<br />
spikes can cause permanent damage to<br />
any semiconductor (ICs, microprocessors,<br />
and LEDs too).<br />
By specifying a soft start, these ugly<br />
current spikes can be easily avoided.<br />
A soft start circuit assures the drive<br />
wires are at zero volts when the switch<br />
is open. With the closing of the switch,<br />
the current rises from zero to the design<br />
parameters without the current spike<br />
shown before. This is analogous to the<br />
leaving the nozzle on the hose open<br />
while turning on the water at the faucet.<br />
It takes a little time for water to reach<br />
the nozzle, and when it does, the flow<br />
rises to the desired amount.<br />
We have shown how improperly<br />
specified driver circuits can and will<br />
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Lighting<br />
introduce semiconductor damaging<br />
current spikes. Properly specifying the<br />
driver assures effective current regulation.<br />
<strong>Design</strong>ing for a “Soft Start” is not<br />
an unusual request, hard to do, or more<br />
expensive. A search of National Semiconductor’s<br />
WEBBENCH ® tools site<br />
revealed they have over 200 products in<br />
their catalog that, by design, are “Soft<br />
Starting” ICs to drive LEDs and other<br />
semiconductors. Further, with WEB-<br />
BENCH ® one can immediately download<br />
a reference design with complete BOM<br />
based on your chosen Luxeon LED and<br />
operating parameters.<br />
Other driver manufacturers also sell<br />
driver electronics that are specifically<br />
designed to work with high-power LEDs<br />
such as the LUXEON I, LUXEON III,<br />
LUXEON V, LUXEON K2, LUXEON Rebel<br />
and LUXEON K2 with TFFC, and “Soft<br />
Start” is only one driver characteristic of<br />
interest. But it is a critical one.<br />
www.philipslumileds.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong><br />
PowefulComboAd.indd 1 3/13/08 5:58:47 PM<br />
43
46<br />
<strong><strong>Power</strong>ing</strong> <strong><strong>Power</strong>ing</strong> <strong>Freight</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
& <strong>Transportation</strong><br />
Transport and Automotive<br />
Applications Benefit from<br />
Multiphase Boosters<br />
<strong>Design</strong> for reduced EMI, higher efficiency,<br />
faster transient response<br />
High power step-down DC/DC converters have long benefited from multiphase operation. But all<br />
the advantages of multiphase operation, such as reduced input and output ripple currents, lower<br />
output noise and lower component stresses, can also be realized in step-up applications. Many of the<br />
controllers used in step-down applications can also be used in step-up applications and generally have<br />
2 phases, which may not provide enough output power or have the ability to keep the phase currents<br />
balanced. They also usually need extra support components, like gate drivers, extra bias voltage and an<br />
external error amplifier to complete the circuit.<br />
By Bruce Haug, Product Marketing Engineer and Tick Houk, <strong>Design</strong> Engineer,<br />
Linear Technology Corporation<br />
Until recently, most high power<br />
step-up converters have utilized<br />
non-optimized solutions due to<br />
the lack of an available multiphase boost<br />
controller. The most common nonsynchronous<br />
2-phase step-up converter<br />
solution has been to use the top-side<br />
drivers of a 2-phase synchronous stepdown<br />
controller configured to drive two<br />
low-side power MOSFETs 180 degrees<br />
out-of-phase. Another solution has been<br />
to use 2 or more single-phase step-up<br />
controllers and an external clock circuit<br />
to achieve the required channel-tochannel<br />
phase relationship. Other nonoptimized<br />
solutions have used either<br />
push-pull or dual interleaved forward<br />
controllers in a non-isolated step-up<br />
configuration. However, all of these solutions<br />
suffer from significant drawbacks<br />
which limit their utilization in many of<br />
today’s demanding applications.<br />
In the automotive environment, the<br />
next generation of low emissions diesel<br />
fuel injection systems requires up to<br />
2 amps of output current at an output<br />
voltage in the 70V to 110V range, and<br />
delivered from a 12V battery that can<br />
vary from 9V to 28V. This input-tooutput<br />
voltage conversion requires a<br />
boost converter capable of greater than<br />
92% duty cycle with constant frequency<br />
operation.<br />
Furthermore, high power car audio<br />
amplifiers often need a main supply rail<br />
in the 25V to 35V range with the ability<br />
to supply peak power levels approaching<br />
1000W, making multiphase operation<br />
essential. By splitting the power<br />
stage into multiple paralleled phases,<br />
thermal stress is reduced on the power<br />
components, thereby reducing output<br />
voltage ripple and noise, allowing the<br />
use of smaller output capacitors, and<br />
improving system efficiency.<br />
As power densities continue to rise,<br />
multiphase boost designs become a<br />
necessary option to keep input currents<br />
manageable, increase efficiency and increase<br />
power density. With mandates on<br />
automotive energy savings more common,<br />
a multiphase converter topology<br />
may be the only way to achieve these<br />
design objectives. A 2-phase or higher<br />
phase converter built around Linear<br />
Technology’s LTC3862, can demonstrate<br />
the benefits of this type of approach.<br />
A Multiphase Solution<br />
The LTC3862 is a non-synchronous<br />
multiphase controller capable of operating<br />
in boost, SEPIC and flyback topologies.<br />
This controller utilizes a constant<br />
frequency, peak current mode control<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
The AP300 Analyzer and POWER 4-5-6 Software are designed<br />
specifically for the power electronics engineer. Now, they<br />
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POWER 4-5-6 greatly accelerates your design process in<br />
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Email: DRidley@ridleyengineering.com
48<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
Figure 1: A Two-Phase, 72V Output, Low Emissions Automotive Fuel Injection Boost Converter Using the LTC3862-1.<br />
scheme with its two power stages operating<br />
180 degrees out-of-phase. Each<br />
power stage is comprised of a single<br />
inductor, MOSFET, Schottky diode and<br />
current sense resistor. The two phases<br />
are balanced closely with a tight current<br />
limit threshold and a highly accurate<br />
transfer function from the ITH pin (the<br />
output of the error amplifier) to the current<br />
comparator sense inputs, both from<br />
channel-to-channel and chip-to-chip.<br />
Because of this, the peak inductor current<br />
matching is kept accurate, forcing a<br />
balanced current in multiphase applications.<br />
In a two-phase converter, only one<br />
LTC3862 IC is required, and the two<br />
output stages are driven 180 degrees<br />
out-of-phase. In a 3-phase converter,<br />
two LTC3862 chips are needed (2<br />
channels from the master and 1 channel<br />
from the slave) and the output<br />
stages are driven 120 degrees out-ofphase.<br />
Similarly, a 4-phase converter<br />
utilizes 2 LTC3862 IC’s with each<br />
channel running 90 degrees out-ofphase.<br />
And so on until a 12 phase<br />
application, where 6 chips would be<br />
used, with each channel operating<br />
30 degrees out-of-phase. By splitting<br />
the current into multiple power paths,<br />
conduction losses can be reduced<br />
and thermal stresses can be balanced<br />
between a larger number of components<br />
and over a larger area on the board,<br />
and output noise can be significantly<br />
reduced. Conversely, for a given output<br />
voltage ripple, multiphase operation will<br />
result in a smaller total output capacitance,<br />
which is especially important in<br />
high voltage applications where the voltage<br />
coefficient of the output capacitor<br />
typically reduces the effective capacitance.<br />
The LTC3862 contains two PMOS<br />
output stage low dropout (LDO) voltage<br />
regulators, one for the powerful onboard<br />
gate drivers (which contain 2.1<br />
Figure 2: LTC 3862 Current Sense Circuit.<br />
Ohm PMOS source transistors and 0.7<br />
Ohm NMOS sink transistors) and one<br />
LDO for the low voltage analog and<br />
digital control circuitry. Low dropout<br />
operation allows the input voltage to dip<br />
to a lower value before circuit operation<br />
is affected. This is especially important<br />
in automotive applications, where the<br />
cold cranking of an engine can result<br />
in a battery voltage droop to as low as<br />
4V. The LTC3862 provides a 5V gate<br />
drive for logic level MOSFETs and the<br />
LTC3862-1 provides a 10V gate drive<br />
normally required for higher output voltage<br />
applications.<br />
A Low Emissions Diesel Fuel<br />
Injection <strong>Power</strong> Supply<br />
Figure 1 illustrates a boost converter<br />
designed for low emissions diesel<br />
fuel injection systems. This converter<br />
operates over a wide input voltage<br />
range to accommodate the variation<br />
of an automotive battery, from a cold<br />
crank condition to a double battery<br />
connection for jump starts. Because<br />
of the wide input voltage range (8.5V<br />
to 36V), the converter must be able<br />
to operate at very high duty cycles<br />
and still maintain constant frequency<br />
operation. The LTC3862 has a<br />
minimum on-time of approximately<br />
180ns and a maximum duty cycle of<br />
96%, with both of these parameters<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
being user programmable. The operating<br />
frequency can be programmed from<br />
75kHz to 500kHz using a single resistor,<br />
and a phase lock loop can be used<br />
to synchronize the operating frequency<br />
to an external clock source. For the<br />
example, the power MOSFETs used in<br />
Figure 1 are the HAT2267H from Renesas,<br />
a 57μH inductor with a saturation<br />
current rating of 5A, and a total output<br />
capacitance of only 107μF is necessary.<br />
The output capacitance consists of two<br />
47μF aluminum electrolytic bulk capacitors<br />
connected in parallel with six low<br />
ESR 2.2μF ceramic capacitors, in order<br />
to meet the output voltage ripple and<br />
RMS current requirements. This con-<br />
www.powersystemsdesign.com<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
figuration also limits the output voltage<br />
ripple to only 500mV.<br />
This circuit operates with a peak efficiency<br />
of 96% at an input voltage of<br />
32V. Because a single-ended boost converter<br />
regulates the current in the source<br />
of the low-side switch, the maximum<br />
current that can be delivered to the<br />
load is a function of the input voltage.<br />
As a result, this converter is capable of<br />
delivering 0.5A to the load at an input of<br />
8.5V, 1.5A at an input of 24V, and 2A at<br />
an input of 32V to 36V.<br />
The LTC3862 features two pins, CLK-<br />
OUT and PHASEMODE that allow mul-<br />
Figure 3: A 12V Input, 24V/5A Output 2-Phase Car<br />
Audio <strong>Power</strong> Supply Using the LTC3862, and Its<br />
Associated Efficiency Curve.<br />
tiple ICs to be daisy-chained together<br />
for higher current multiphase applications.<br />
For a 3- or 4-phase design, the<br />
CLKOUT signal of the master controller<br />
is connected to the SYNC input of the<br />
slave controller in order to synchronize<br />
additional power stages for a single high<br />
current output. The PHASEMODE pin<br />
is used to adjust the phase relationship<br />
between channel 1 and CLKOUT, as<br />
summarized in Table 1. The phases are<br />
calculated relative to the zero degrees,<br />
defined as the rising edge of the GATE1<br />
output. In a 6-phase application, the<br />
CLKOUT pin of the master controller<br />
connects to the SYNC input of the 2nd<br />
controller and the CLKOUT pin of the<br />
49
50<br />
2nd controller connects to the SYNC<br />
input of the 3rd controller.<br />
Additional Features<br />
The LTC3862 error amplifier is a<br />
transconductance amplifier, meaning<br />
that it has high DC gain and high output<br />
impedance. This style of error amplifier<br />
greatly eases the task of implementing<br />
a multi-phase solution, because the amplifiers<br />
from two or more controllers can<br />
be connected in parallel. In a multiphase<br />
application requiring more than one IC,<br />
all of the FB pins should be connected<br />
together and all of the ITH pins should<br />
be connected together. The composite<br />
transconductance of the error amplifier<br />
is simply the sum of the number of ICs<br />
connected together, multiplied by the<br />
660μS of each amplifier. This parallel<br />
connection of error amplifiers is not<br />
possible with control ICs that use a true<br />
operational amplifier, since this amplifier<br />
type has a very low output impedance.<br />
In addition to using parallelable error<br />
amplifiers, the transfer function from<br />
the ITH pin to the current sense comparators<br />
is very accurate, in order to<br />
provide the best channel-to-channel<br />
and chip-to-chip current sense threshold<br />
matching possible. This phase-tophase<br />
current matching is especially<br />
important in high current applications,<br />
where resistive losses are proportional<br />
to the square of the current. Minimizing<br />
the mismatch between channels, results<br />
in a balanced thermal design, which<br />
prevents hot spots on the PCB and possible<br />
thermal runaway.<br />
The LTC3862 has a maximum current<br />
sense threshold of each phase of 75mV,<br />
which allows for a relatively lower power<br />
sense resistor, reducing the circuit size,<br />
increasing efficiency and eliminating the<br />
need for a current sense transformer. It<br />
also includes leading edge blanking for<br />
the current sense inputs, so an external<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
RC filter is not required. Nevertheless,<br />
some users may benefit from adding an<br />
external filter as shown in Figure 2. If<br />
external RC filters are used on the current<br />
sense inputs, the filter components<br />
should be placed as close as possible<br />
to the SENSE pins, and the connections<br />
to the sense resistor should run parallel<br />
to each other and kelvin-connect to<br />
the resistor in order to avoid parasitic IR<br />
drops. The SENSE+ and SENSE- pins<br />
are high impedance inputs to the CMOS<br />
current comparators for each channel.<br />
Programmable Blanking<br />
The Blank pin on the LTC3862 allows<br />
the user to program the amount of leading<br />
edge blanking at the SENSE pins.<br />
The purpose of leading edge blanking is<br />
to filter out noise on the SENSE at the<br />
leading edge of the power MOSFETs at<br />
turn-on. During the turn-on of the power<br />
MOSFET the gate drive current, the discharge<br />
of any parasitic capacitance on<br />
the SW node, the recovery of the boost<br />
diode charge, and the parasitic series<br />
inductance in the high di/dt path all contribute<br />
to overshoot and high frequency<br />
noise that could cause false-tripping<br />
of the current comparator. Providing a<br />
means to program the blank time allows<br />
users to optimize the SENSE pin filtering<br />
for several applications and can be set<br />
to a minimum on-time of 180ns, 260ns<br />
or 340ns.<br />
An Audio Amplifier Boost Converter<br />
Supply<br />
Figure 3 illustrates a 2-phase car<br />
audio power supply that operates<br />
from a 5V to 24V input and produces a<br />
24V/5A output. The wide input voltage<br />
range covers an automotive input<br />
voltage range and the efficiency curves<br />
are also shown reaching up to 96.5%.<br />
This circuit can be easily extended to<br />
3-, 4-, 6- or 12- phase operation for<br />
higher power applications, with minimal<br />
modifications to the basic design. This<br />
Table 1: Programming the Phase Relationship between Channels.<br />
multiphase boost converter protects the<br />
load from mild overload conditions by<br />
imposing a current limit on each phase<br />
(boost converters are typically not short<br />
circuit proof due to the diode and inductor<br />
connection from input to output).<br />
Audio applications have short-duration<br />
peak power demands that are much<br />
higher than the average output power.<br />
Therefore, the current limit must be set<br />
high enough to satisfy these peak power<br />
requirements.<br />
In order to maintain constant frequency<br />
operation and a low output ripple<br />
voltage, a single-ended boost converter<br />
is required to turn off the power<br />
MOSFET switch every cycle for some<br />
minimum amount of time. This off-time<br />
allows the transfer of energy from the inductor<br />
to the output capacitor and load.<br />
Having a high maximum duty cycle is<br />
desirable, especially in low VIN to high<br />
VOUT applications. The maximum duty<br />
cycle for the LTC3862 is 96% with the<br />
DMAX pin connected to ground. For<br />
other topologies, such as a non-isolated<br />
flyback converter, it is desirable to limit<br />
the maximum duty cycle in order to balance<br />
the volt-sec of the transformer. The<br />
LTC3862 has a maximum duty cycle<br />
that is user-programmable. By floating<br />
the DMAX pin, the duty cycle is limited<br />
to 84%. Connecting the DMAX pin to<br />
the 3V8 supply pin limits the duty cycle<br />
to 75%.<br />
Conclusion<br />
The reduced ripple currents and multiphase<br />
operation allows an LTC3862<br />
based design to have reduced EMI,<br />
higher efficiency, faster transient response,<br />
provide a wider selection of<br />
off-the-shelf components and increase<br />
power density when compared to single<br />
phase alternatives. Multiphase operation<br />
results in lower component stresses,<br />
smaller input and output capacitance,<br />
smaller solution size, better thermal<br />
management, and lower output noise.<br />
With its programmability up to 12 phases<br />
using multiple daisy-chained controllers,<br />
the LTC3862 serves the needs of<br />
step-up power supplies from 100W to<br />
1000W in automotive fuel injection systems<br />
and high power audio amplifiers.<br />
www.linear.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
www.circuitprotection.com<br />
Cure for the Uncommon <strong>Power</strong> Source<br />
Barrel jacks are a simple and effective way of connecting portable electronics to<br />
an external power supply. But what happens when the user plugs into a supply<br />
operating at the wrong voltage? Or what about when the supply is dirty and full<br />
of nasty voltage surges, as is often the case when power is supplied from an<br />
automobile power jack? Raychem Circuit Protection PolyZen devices can help<br />
protect your DC power ports by clamping excess voltages and smoothing<br />
inductive voltage surges. The PolyZen device's unique polymer-protected<br />
precision Zener design can help cure these all-too-common power problems.<br />
To learn more, visit www.circuitprotection.com/polyzen.<br />
Features<br />
• Overvoltage transient suppression<br />
• Stable Vz vs fault current<br />
• Time delayed, overvoltage trip<br />
• Time delayed, reverse bias trip<br />
• <strong>Power</strong> handling on the order of<br />
100 watts<br />
• Integrated device construction<br />
• RoHS compliant<br />
Tyco Electronics Raychem GmbH Finsinger Feld 1 85521 Ottobrunn Germany<br />
Tel: +49 89 6089 386 Fax: +49 89 6089 394<br />
© 2008 Tyco Electronics Corporation • www.tycoelectronics.com<br />
Raychem, PolyZen, TE Logo and Tyco Electronics are trademarks<br />
Benefits<br />
• Stable Zener diode helps shield<br />
downstream electronics from<br />
overvoltage and reverse bias<br />
• Analog nature of trip events minimizes<br />
upstream inductive spikes<br />
• Minimal heat sinking requirements<br />
• Single component placement<br />
• Helps reduce warranty returns &<br />
replacement costs<br />
Applications<br />
• Cell Phones • Printers<br />
• PDAs • Scanners<br />
• MP3 Players • Hard Drives<br />
• DVD Players • Desk Phones<br />
• Digital Cameras • USB Hubs<br />
• Media Players • PBX Phones<br />
• Wireless Base Stations
52<br />
<strong><strong>Power</strong>ing</strong> <strong><strong>Power</strong>ing</strong> <strong>Freight</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
& <strong>Transportation</strong><br />
Electric Vehicle Battery<br />
Monitoring<br />
Compact solution for current sensors in<br />
transportation applications<br />
With the higher cost of petrol/gasoline making headline news in recent years, a new urgency has<br />
been placed on alternative methods of propulsion to the traditional combustion engine. Among many<br />
possible alternatives, the battery operated Electric Vehicle (EV) has seen a resurgence of interest and<br />
development.<br />
By Warren Pettigrew, Chief Technical Officer, Raztec Sensors, New Zealand<br />
Two important battery parameters<br />
that are of particular interest to<br />
an Electric Vehicle (EV) operator<br />
are state of charge (SOC), and state of<br />
health (SOH). In order to reliably ascertain<br />
either of these parameters, accurate<br />
current sensing is required over a wide<br />
range of current.<br />
State of Charge<br />
The simple and most common method<br />
of ascertaining SOC is to measure<br />
the battery voltage using a time based<br />
algorithm which takes into consideration<br />
the load condition of the battery.<br />
This method gives reasonably accurate<br />
results under normal operating<br />
conditions. However, if the loading is<br />
particularly heavy (or indeed particularly<br />
light), or if opportunity charging is<br />
incorporated, the accuracy will suffer<br />
substantially. Typically battery charge<br />
gauges indicate a greater capacity than<br />
is available particularly towards the end<br />
of charge or immediately after charging.<br />
The accuracy can be dramatically<br />
improved if current is measured, and<br />
if weighted coulomb counting is performed.<br />
Weighting is necessary to take<br />
into account the reduction of capacity<br />
under heavy loading of the battery.<br />
Coulomb counting is not without its<br />
difficulties as it integrates current with<br />
time – often over long periods. This<br />
means that any offset error is also integrated<br />
which demands that current sensors<br />
must be stable and with minimal<br />
influence from temperature or magnetically<br />
induced hysteresis errors.<br />
State of Health<br />
The battery industry is rapidly coming<br />
to realize that a simple means of<br />
determining the SOH of a battery is to<br />
monitor its float current. As a battery<br />
deteriorates, its float current steadily<br />
increases. One difficulty, however, is obtaining<br />
a suitable current sensor which<br />
will measure from float current levels,<br />
which are fractions of an amp, through<br />
to the many hundreds of possible load<br />
amps. Certain sensors are available, but<br />
their high cost and large physical bulk<br />
make them commercially unattractive.<br />
As a battery ages or deteriorates, then<br />
its float current increases. This increase<br />
in float current can then be used to accurately<br />
predict the remaining life of the<br />
battery.<br />
A common cause of premature battery<br />
failure is from a charger that has a<br />
poor algorithm, or is subject to inappropriate<br />
charging techniques by operators.<br />
Both of these issues are easily detected<br />
if both current and voltage are sensed<br />
with time. These techniques can prevent<br />
expensive premature battery failure<br />
whilst greatly extending battery operating<br />
life. The cost of monitoring is very<br />
quickly recovered from the lower battery<br />
operating cost.<br />
If the monitor includes extended<br />
time logging, warranty disputes can be<br />
quickly resolved and the battery manufactures<br />
will have solid, dependable<br />
data available to close product manufacturing<br />
quality loops.<br />
The relatively small investment in current<br />
sensing as part of battery monitoring<br />
can result in substantial savings in<br />
system operating costs.<br />
Raztec RAZL1500 in EV<br />
applications<br />
The Raztec Link has a performance<br />
that matches or exceeds the very<br />
best open loop current sensors, yet is<br />
extremely compact and economically<br />
priced. EV applications, where high current<br />
measurement, fast response and<br />
more importantly; small physical size,<br />
ease of mounting – both electrically and<br />
physically – galvanic isolation and excellent<br />
signal/noise ratio is required, can include<br />
Electric Cars, Rail Transport, Earth<br />
Moving and Electric Fork-Lift Trucks.<br />
Whilst probably not as high-profile as,<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
Figure1. Raztec Link with forklift.<br />
for example, the electric or hybrid car<br />
application, the electric fork-lift truck<br />
demands much the same technology,<br />
but more so in almost every area.<br />
Due to its small physical size and superior<br />
performance in electrically noisy<br />
environments, the RAZL1500 is ideally<br />
suited for mounting in the most convenient<br />
location, irrespective of concerns<br />
regarding traditional current shunts such<br />
as physical size, generated heat, electrical<br />
noise etc . . .<br />
Traditionally, current sensing in<br />
EV’s has comprised of current shunts.<br />
Whilst this technology has proven to be<br />
satisfactory in the past, it has certain<br />
limitations and side-effects that make it<br />
far less attractive for use in modern EV<br />
designs. Firstly, its large physical size<br />
www.powersystemsdesign.com<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
makes demands on the ever decreasing<br />
hardware real estate, the heat generated<br />
during measurement, common-mode<br />
voltage issues and in particular, the very<br />
small signal at low current compared<br />
to the general level of electrical noise.<br />
The figures contained in table1 serve to<br />
highlight these shortcomings.<br />
Physically, the Raztec Link current<br />
sensor looks rather like a fuse or even<br />
a very small shunt but offers some very<br />
significant technical advantages over<br />
shunts when it comes to measuring current.<br />
• Galvanic isolation between the<br />
measured current and the output up to<br />
3000V.<br />
• Negligible power loss<br />
• 4500mV differential output voltage<br />
(no signal amplification required)<br />
• Superior signal-to-noise ratio<br />
• Small physical size<br />
Retained features:<br />
• Excellent frequency response to<br />
350KHz<br />
• Excellent linearity<br />
• Very low drift of null output voltage<br />
• Competitive cost<br />
• Excellent immunity to stray electric<br />
and magnetic fields.<br />
• 5V operation<br />
The key to accuracy is linearity of<br />
response. Linearity can be measured by<br />
deviation from an ideal linear response,<br />
normally expressed as a percentage of<br />
full scale. Full scale requires specifying,<br />
as saturation is inevitable. The 1500A<br />
link has better than 1% linearity over<br />
+/-1000A.<br />
Open-loop sensors are vulnerable to<br />
drifts of transfer function with temperature.<br />
Raztec link sensors are configured<br />
to assure negligible negative drift with<br />
increasing temperature. With most current<br />
control circuits it is advisable that<br />
the output indicates high with increasing<br />
temperature, thus improving safety<br />
and reliability. Typical drift for the Link is<br />
54<br />
Figure 2. Raztec Link schematic.<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
ing is employed to reduce the possible<br />
effects of noise from high voltage<br />
switching transients and nearby current<br />
carrying conductors.<br />
Noise on the primary voltage can be<br />
capacitively coupled through to the sensor<br />
output – normally as spikes which<br />
can be significantly large. The coupling<br />
effect can be mitigated by providing<br />
electrostatic screening between the<br />
primary voltage and the magnetic field<br />
sensors. Sensor installers must also<br />
ensure that screened output cables<br />
are routed away from noisy potentials.<br />
Another technique to avoid noise effects<br />
when sensing via an Analog to Digital<br />
converter to a microcomputer is to not<br />
attempt to measure the current during<br />
current switching thus avoiding the<br />
noise spike. The Link superimposes a<br />
voltage less than 1V for a primary transient<br />
of 108V/s.<br />
The Link uses Hall sensors that have<br />
an insignificant noise output compared<br />
with useful output voltages.<br />
The use of two Hall elements also provides<br />
an output signal with significantly<br />
improved temperature stability.<br />
Summary<br />
As is so often the case, ‘one size does<br />
NOT suit all’. What the author is attempting<br />
to highlight in this article is that<br />
there is often more than one solution to<br />
a given application need, particularly in<br />
current measurement. Where physical<br />
size and power consumption/thermal<br />
performance is considered not to be<br />
particularly high on the design list of<br />
criteria, then traditional current-shunts<br />
may well fit the bill.<br />
However, with modern Electric Vehicles<br />
where battery life and predictability<br />
of charge are paramount, a current<br />
sensor that enables the design engineer<br />
to accurately determine both SOC and<br />
SOH of the traction battery results in<br />
higher performance, greater productivity,<br />
extended battery life and reduced<br />
running and maintenance costs on the<br />
part of the operator.<br />
electronica: Hall A2, Stand 544<br />
www.raztec.co.nz<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
www.powersystemsdesign.com<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
Circuit Protection for<br />
Safer Automotive Electrical<br />
Architectures<br />
Added protection is vital for bus and truck<br />
wire harnesses<br />
The wiring-harness architecture found in trucks, buses and other vehicles with electrical systems based<br />
on 24V technology continues to move forward as more electrical and electronic content is required. It<br />
is not just the conventional functions such as heating, air conditioning and ventilation that now require<br />
electronic control, but the many new systems being introduced within the cab such as GPS (global<br />
positioning systems), sound and communication systems which are adding to the electrical load.<br />
By Guillemette Paour, Automotive Marketing Manager for Raychem Circuit Protection Products,<br />
Tyco Electronics<br />
There is a common misconception<br />
amongst consumers that fuses are<br />
only there to protect them from injury<br />
from devices that have developed a<br />
fault. Due to their historical Amp rating (3,<br />
5, 13A) they are often seen as particularly<br />
essential for home appliances that<br />
require greater power, such as kettles,<br />
toasters or ovens, as opposed to cars,<br />
buses, lorries and larger appliances or<br />
white goods. This is understandable to<br />
an extent. It would seem reasonable<br />
to view the fuse as the ‘weakest link’,<br />
something that will stand between an<br />
electrical supply and someone suffering<br />
serious injury from a shock in the event<br />
of an appliance developing a fault.<br />
Within the engineering community,<br />
there is no such misconception. It is understood<br />
that fuses are used to protect<br />
the wire or cable supplying the power<br />
to it and as a result the equipment<br />
and user. The fuse is the safety valve<br />
against the appliance being powered,<br />
if it has developed a fault. Without a<br />
fuse the power would continue to flow,<br />
which would ultimately result in the wire<br />
overheating and possibly igniting. This<br />
scenario is still the cause of many house<br />
fires and increasingly the cause of the<br />
smouldering cars that are seen at the<br />
roadside.<br />
Some might say this is a subtle difference<br />
and is not relevant, but it becomes<br />
more applicable in environments where<br />
the density of wires carrying power is<br />
rapidly increasing. Today, one of the<br />
densest environments for power carrying<br />
cables is in vehicles, where manufacturers<br />
are under constant pressure<br />
to continue adding new features. This is<br />
not just applicable to cars. The wiringharness<br />
architecture found in trucks,<br />
buses and other vehicles with electrical<br />
systems based on 24V technology has<br />
also undergone considerable change<br />
as electrical and electronic content has<br />
increased. Conventional functions, such<br />
as the HVAC (heating, ventilating & air<br />
conditioning) system, continue to be<br />
converted to electronic control while<br />
many new features, such as GPS (global<br />
positioning systems) and entertainment<br />
systems, are being added to the electrical<br />
load.<br />
The power hierarchy used within vehicles<br />
is typically distributed. Each device<br />
that requires power receives it as a spur<br />
from a larger supply – typically using<br />
larger cables. This hierarchy architecture<br />
minimises the amount of high power<br />
cable needed, which clearly represents<br />
both increased cost and weight. However,<br />
for every added powered device<br />
there is a need to supply power to it.<br />
This forces compromises in the ideal hierarchical<br />
or ‘tree’ wiring structure with<br />
main power trunks dividing into smaller<br />
and smaller branches using overcurrent<br />
protection at each node.<br />
So, in addition to delivering the power,<br />
there is the added need to protect the<br />
cable or wire that carries it. Because a<br />
hierarchal architecture can use smaller<br />
wires and relays on its “smaller branches.”<br />
The resulting harness is smaller<br />
and lighter, providing cost savings, both<br />
in materials and fuel consumption. In<br />
addition, a distributed architecture can<br />
provide system protection together<br />
with fault isolation, which can reduce<br />
warranty costs and increase customer<br />
satisfaction.<br />
The space restrictions within<br />
today’s vehicles impose compromises.<br />
55
56<br />
As each device is added, it is necessary<br />
to also consider the impact it will have<br />
on the wiring harness. Not only that, but<br />
in order to provide adequate protection<br />
for the harness it is also necessary to<br />
consider how that protection – against<br />
overloads or short circuits – will be<br />
added, and where.<br />
Figure 1: Tyco’s Polymeric Positive<br />
Temperature Coefficient (PPTC) devices.<br />
Traditional fuses are designed to be<br />
replaced following a fault, so it is essential<br />
that they are located in an accessible<br />
area to a user or service engineer. That<br />
may not necessarily be close to the actual<br />
device being powered. For instance,<br />
in the case of an electrically adjustable<br />
seat, the motors will be positioned<br />
beneath the seat in an area not easily<br />
accessible. Without careful design,<br />
replacing a fuse could involve removing<br />
the seat, adding significant cost to the<br />
repair. Locating fuses in user-accessible<br />
areas has consequences. If the device<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
being powered is not located near an<br />
access point, it becomes necessary to<br />
route the wiring harness much further<br />
- between the device being powered,<br />
to the fuse and back again, perhaps<br />
doubling the length of wire needed but,<br />
more significantly, doubling the voltage<br />
drop across the total length of wire.<br />
<strong>Power</strong> demands and, inextricably,<br />
voltage drops within the automotive environment<br />
are leading to manufacturers<br />
looking at increasing the voltage level<br />
used within the car. Currently, 12V is<br />
standard for passenger cars and 24V for<br />
trucks and buses. These battery voltage<br />
levels are likely to increase to 42V in the<br />
future, to accommodate a greater number<br />
of electrical devices and the power<br />
they require while downsizing the wires.<br />
Fuel economy and reduced emissions<br />
are two of the multiple reasons for the<br />
change.<br />
The heavy-duty vehicle 24V systems,<br />
like the 12V must incorporate protection.<br />
With higher levels of voltage it<br />
becomes necessary to provide higher<br />
levels of protection, which can lead<br />
to the use of larger, heavier and more<br />
expensive solutions.<br />
As shown in Figure 1, there is now an<br />
alternative available to conventional protection<br />
systems, which provides greater<br />
access to localised protection. It comes<br />
in the form of polymeric positive temperature<br />
coefficient (PPTC) devices. These<br />
components are typically smaller than<br />
conventional protection schemes and use<br />
a technology that offers greater flexibility,<br />
both in their positioning and their use.<br />
Figure 2: PPTC devices provide flexibility to the location of the fuse.<br />
A PPTC device can be used multiple<br />
times. Key to its operation lies in the<br />
name, positive temperature coefficient.<br />
The more current the device sees, the<br />
hotter it gets and the higher its resistivity<br />
becomes. As a result, it lets progressively<br />
less current pass, protecting the<br />
wiring harness. The added benefit of the<br />
PPTC device over a traditional fuse is<br />
that once the power is cycled and the<br />
device cools down it resets and is able<br />
to function again. That means once the<br />
fault has been resolved, the device is<br />
ready to start passing a current again<br />
without needing to be replaced. As<br />
shown in Figure 2, this brings in a great<br />
deal of flexibility, with respect to where<br />
the fuse can be placed and the wiring<br />
harnesses it can protect.<br />
The technology that has been used<br />
extensively in the automotive world was<br />
limited to use inside the cockpit for 24V<br />
systems. However, recent developments<br />
have led to the development of the new<br />
range of PolySwitch AHEF devices from<br />
Tyco Electronics.<br />
Developed to operate in harsh conditions<br />
while delivering the necessary<br />
performance, the AHEF devices are<br />
available with current ratings from 0.5A<br />
to 10A and are rated to operate across a<br />
temperature range of -40°C to +125°C.<br />
This permits their use in both passenger<br />
and engine compartments. These devices<br />
give designers the ability to locate<br />
junction boxes close to their intended<br />
electronics, whether in the passenger<br />
compartment to help protect BCUs<br />
(Body Control Units) or in the engine<br />
compartment to help protect HVAC controls<br />
for instance.<br />
The development of these 32V<br />
rated through-hole PPTC devices has<br />
allowed for more scope in the design<br />
of the wiring harness, enabling it to<br />
be optimised for the devices being<br />
powered. By providing resettable<br />
protection, placement is available in<br />
inaccessible locations, such as under<br />
the seat, over the driver console or in<br />
door panels thereby enabling design<br />
engineers to get the power to where<br />
it is needed.<br />
www.circuitprotection.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
58<br />
<strong><strong>Power</strong>ing</strong> <strong><strong>Power</strong>ing</strong> <strong>Freight</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
& <strong>Transportation</strong><br />
One Step Closer to<br />
the Birds<br />
Glider uses Vicor battery-controlled electrical<br />
propulsion to take to the air<br />
Gliding is one of the most exhilarating sports in the world. It offers a direct experience of air, wind and<br />
weather in a seemingly limitless space, and comes closest to man’s vision of the freedom of a bird’s<br />
flight. Crucial to this type of flying is the need to gain height in order to reach a thermal. Traditionally, a<br />
winch or a tow plane is used to pull the glider to sufficient altitude so that the fun of gliding in search of<br />
a thermal can begin. The requirement to return to the home airfield without additional support limited the<br />
use of gliders, and made careful flight planning a necessity.<br />
By Marco Panizza, European Applications Engineer, Vicor Europe, Germany<br />
Auxiliary propulsion systems<br />
brought an increase in range and<br />
flexibility, and made it possible<br />
to start gliders without additional towing<br />
tools. A conventional solution was<br />
using combustion motors. However, the<br />
performance of a combustion motor de-<br />
creases with its operating altitude. Combustion-powered<br />
propulsion systems<br />
must be oversized in order to deliver the<br />
desired power at all operating altitudes,<br />
and impose an important weight and<br />
noise burden on the glider. Additionally<br />
combustion engines generate substan-<br />
Figure 1: The Antares 20E glider in climb. The aircraft is driven by a propeller powered<br />
by an electric motor on a hinged carrier beam.<br />
tial heat, and must be allowed to cool<br />
down before being retracted into the<br />
fuselage.<br />
The design team at Lange Flugzeugbau<br />
in Zweibruecken, Germany wanted<br />
to set pilots free by adding an electric<br />
engine for self-powered takeoff<br />
and climbing. The company<br />
used Vicor modules to design<br />
the Antares 20E, the first glider<br />
to receive the prestigious EASA<br />
(European Aviation Safety<br />
Agency) type certification for<br />
an electrical propulsion system,<br />
and one of only three electrically<br />
powered gliders on the market.<br />
The glider’s easy to use retractable<br />
electric propulsion solution<br />
is more reliable, quieter, and<br />
produces less vibration than<br />
traditional combustion engines.<br />
Offering high performance<br />
independent of operating altitude,<br />
electric motors provide<br />
the safest and most convenient<br />
choice for power. By integrating<br />
the entire battery charging<br />
circuitry inside the plane, Lange<br />
produced a completely self-reliant<br />
electrically-powered glider<br />
that can make long-distance<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
flights, and be recharged at any airfield.<br />
The need for good aerodynamic<br />
performance, however, imposes strict<br />
limits on the weight of the entire system,<br />
particularly that of batteries and charging<br />
circuitry.<br />
<strong>Design</strong> challenges<br />
One of the challenges in the design<br />
of the glider was the integration of the<br />
battery charging subsystem. The entire<br />
system had to be self-reliant in order to<br />
enable long-distance multi-lap flights<br />
without the need for an external charging<br />
unit at the airfield. The propulsion<br />
motor has a nominal power of 42kW<br />
and operates on a voltage of 288V. The<br />
battery system has to provide enough<br />
power for five minutes of operation or<br />
about 3000m of climbing altitude, which<br />
translates into an overall battery capacity<br />
of 11kWh. Charging has to use a<br />
normal single-phase mains connection,<br />
and a full charging cycle needs to be<br />
completed overnight.<br />
The glider uses Li-Ion battery cells<br />
which require tightly controlled operating<br />
conditions to deliver a consistent,<br />
reliable power output. In order to offer<br />
maximum capacity, the cells must be<br />
operated between 20 and 40°C, so<br />
temperature sensing and cell heating<br />
had to be implemented. Additionally all<br />
cells must be kept on the same charging<br />
state, requiring cell voltage monitoring<br />
circuitry to ensure that all cells<br />
have identical cell voltages. Before any<br />
charge cycle, all cells are discharged to<br />
have the same cell voltage with a tolerance<br />
of only ±20mV ensuring that all<br />
cells will be charged evenly. In practice,<br />
charging is several activities that must<br />
be performed in sequence:<br />
• Cell voltage monitoring and selective<br />
discharging until all cells have the same<br />
voltage within the specified tolerance<br />
• Cell heating until the desired operating<br />
temperature is reached<br />
• Battery array charging until the total<br />
voltage reaches 288V<br />
In addition, the charging electronics<br />
have to fit into the overall system of the<br />
glider. This means that the circuitry has<br />
to meet rigorous, weight, heat management<br />
and size specifications.<br />
www.powersystemsdesign.com<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
Choosing a charging<br />
module vendor<br />
Since total glider weight has a direct<br />
impact on its flying performance, all<br />
components in the aircraft had to be optimized<br />
for lowest possible weight. Commercially<br />
available chargers that met the<br />
specifications would weigh about 10kg<br />
including mains front-end and cabling –<br />
much too heavy for integration in a glider<br />
with a maximum total takeoff weight of<br />
660kg. As Lange’s design engineers<br />
could not find ready-made charging<br />
units that met the weight requirements,<br />
a new charging subsystem had to be<br />
developed.<br />
The charging subsystem essentially<br />
consists of a mains front-end and a high<br />
voltage, high-power DC-DC converter<br />
with programmable output voltage.<br />
Due to space and weight limitations,<br />
the circuits had to offer high efficiency,<br />
as a major factor in the overall weight<br />
Figure 2: Charging system block diagram. The front-end and the power section<br />
are housed in two separate cabinets and are mounted in the glider’s fuselage.<br />
The front-end consists of the EN1C21 Vicor modules while the power section<br />
comprises Vicor Module V300B48T250BL Vicor DC-DC converters. The power<br />
section is connected to the battery array, which is installed inside the wings.<br />
59
60<br />
of the system would be whether bulky<br />
heat sinks were needed for thermal<br />
management. The weight, efficiency<br />
and controllability specifications called<br />
for the use of semi-customized circuit<br />
modules, and Vicor was the only manufacturer<br />
that could deliver modules that<br />
were both sufficiently light-weight and<br />
still met the efficiency, controllability and<br />
volume specifications.<br />
Implementation with a focus<br />
on weight and efficiency<br />
The charging subsystem is operated<br />
by a dedicated controller, which<br />
communicates with the glider’s system<br />
computer via CAN bus. The charging<br />
cycle is only activated after completion<br />
of the other steps described<br />
above. For space, weight and thermal<br />
management reasons, the subsystem<br />
is divided into two sections, the auto<br />
ranging mains front-end and the power<br />
section which contains the DC-DC<br />
converters.<br />
During a charging cycle, only the<br />
power section generates substantial<br />
heat. The glider electronics contain<br />
www.heatmanagement.com<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
POWERCLIPS ® Integrated<br />
Heat Management Solutions<br />
for semiconductor<br />
mounting More than 35<br />
standard types available from<br />
stock for all kinds of transistor<br />
packages Samples available<br />
free of charge.<br />
Kunze Folien GmbH · P.O.Box 1562 · 82036 Oberhaching · Germany<br />
Phone +49 (0)89 66 66 82-0 · Fax +49 (0)89 66 66 82-10 · sales@heatmanagement.com<br />
Figure 3: Featuring high efficiency and low weight, the Vicor V300B48T250BL<br />
DC-DC converters are the heart of the charging system.<br />
another element that generates substantial<br />
heat during powered flight: the<br />
motor control circuitry. Since motor and<br />
charging electronics are never used at<br />
the same time, the power section and<br />
the motor control circuitry can share the<br />
same heat sink, reducing weight. The<br />
Vicor DC-DC converter modules contain<br />
a metal base plate which serves both<br />
to mount the module and to establish a<br />
thermally conductive contact to a heat<br />
sink, yielding a very compact, lightweight<br />
design.<br />
The battery<br />
array consists<br />
of 72 highperformance<br />
Li-<br />
Ion cells which<br />
are connected<br />
in series. The<br />
batteries operate<br />
with cell<br />
voltages of<br />
2.7V (‘empty’)<br />
to 4.0V (‘full’),<br />
so that the<br />
circuitry has to<br />
deliver a charge<br />
voltage ranging<br />
from 194V<br />
to 288V, which<br />
is determined<br />
using a cell voltagemeasurement<br />
which is<br />
performed by<br />
the charge controller<br />
at regular<br />
intervals. The<br />
charge controller<br />
derives a<br />
trim voltage<br />
from this mea-<br />
surement and delivers it to the DC-DCconverters<br />
so that the charge voltage<br />
is updated in relation to the batteries’<br />
status. The controller also limits the trim<br />
voltage so that the converters cannot<br />
deliver a higher voltage than 290V, thus<br />
protecting the battery array against<br />
overcharging. As it is only used on the<br />
ground and not during flight operation<br />
Lange did not need to implement any<br />
redundancy in the charging system.<br />
Due to the efficiency and light-weight<br />
design of the deployed Vicor circuit<br />
modules, the resulting charging unit only<br />
weighs 6kg including cabling, freeing<br />
more weight for valuable payload. The<br />
unit consumes approximately 1.7kW<br />
of mains power, and requires just nine<br />
hours to fully recharge the glider’s batteries.<br />
The auto ranging mains frontend<br />
of the charger is compatible to mains<br />
voltages from 110 to 230VAC, and is<br />
thus usable world-wide.<br />
Conclusion<br />
The Antares glider’s self-contained<br />
electrical drive system has moved<br />
man’s flight one step closer to the<br />
elegance and freedom of the birds. The<br />
outstanding electrical power to weight<br />
ratio and high efficiency of the Vicor<br />
solution allowed the design team to<br />
integrate the battery charging system<br />
within the plane without compromising<br />
the flight performance – something that<br />
is crucial to the fascination and thrill of<br />
glider flight.<br />
electronica B2.311 & A5.313<br />
www.vicoreurope.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
<strong><strong>Power</strong>ing</strong> <strong><strong>Power</strong>ing</strong> <strong>Freight</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
& <strong>Transportation</strong><br />
Progressing <strong>Freight</strong> and<br />
Ultracapacitors in energy saving applications<br />
A growing number of energy experts worry about the world's lack of preparation for “peak oil,”<br />
a term referencing the point at which the amount of petroleum that is economically feasible to extract<br />
and refine goes into decline. Peak oil does not mean running out of oil, but rather signifies the end<br />
www.powersystemsdesign.com<br />
of the cheap-fuel era.<br />
By Sven Baechtiger, Key Account Manager, Heavy <strong>Transportation</strong>, Maxwell Technologies<br />
Oil prices have plunged approximately<br />
30% since surging to a<br />
record $147.27 a barrel in July of<br />
2008. Does this indicate that the crisis<br />
is over? The US per capita oil consumption<br />
is 25 barrels annually. Additionally,<br />
both China and India are consuming<br />
below 2 barrels for the collective population<br />
of 2.5 billion citizens in these locations<br />
and there is an expectation that oil<br />
demand will increase in each of these<br />
countries as more of their citizens look<br />
to enjoy the fruits of the energy-hungry<br />
world.<br />
Maxwell Technologies believes industry<br />
needs to alter its mindset in terms<br />
of energy consumption and energy<br />
management. The time when energy<br />
was wasted without concern in braking<br />
resistors, un-adapted diesel engines,<br />
and in un-recovered kinetic energy, has<br />
now gone.<br />
Energy Storage Efficiency in<br />
<strong>Transportation</strong><br />
Hybrid electric busses and cars are<br />
today a familiar concept and can frequently<br />
be seen in many of the<br />
world’s cities. The use of an energy<br />
storage device allows efficient startstop<br />
operation as well as the recovery<br />
of braking energy with fuel consumption<br />
and CO 2 emissions significantly<br />
reduced. These very same principles<br />
are also applicable to heavier vehicles<br />
in public transportation, such as trains,<br />
<strong>Transportation</strong><br />
Figure 1. Wide temperature range and low internal resistance of Ultracapacitors outperform<br />
Batteries.<br />
61
62<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
Figure 2. Maxwell’s BOOSTCAP ® HTM125 module.<br />
trams and metros, all of which benefit<br />
from the adoption of a hybrid power<br />
train approach. Consequently, primary<br />
energy demand and maintenance costs<br />
can be considerably reduced.<br />
The obvious energy storage device<br />
might be a rechargeable battery. However,<br />
such technology shows evidence<br />
of some serious limitations in freight and<br />
transportation applications. Batteries<br />
are heavy in weight, large in size, slow in<br />
charging rate and high in maintenance<br />
costs due to reduced cyclic capabilities.<br />
Furthermore, battery technology suffers<br />
from degraded performance at low temperatures.<br />
Today, heavy transportation application<br />
engineers are considering alternative<br />
energy storage technology - the ultracapacitor.<br />
Ultracapacitors, or doublelayer<br />
capacitors, provide high charge<br />
acceptance, high-efficiency, high cycling<br />
stability, and excellent low-temperature<br />
performance.<br />
Ultracapacitors are therefore the<br />
perfect component to store the heavy<br />
transportation vehicle’s kinetic energy<br />
during frequent braking events. In comparison<br />
to battery chemical reaction,<br />
energy storage in ultracapacitors is<br />
based on an electrostatic reaction with<br />
an extremely short time constant. For<br />
an ultracapacitor, the energy storage<br />
begins as soon as electrons are available.<br />
During the acceleration phase of<br />
the vehicle, the previously stored energy<br />
can be re-injected into the application<br />
thereby avoiding important absorp-<br />
tion in network primary energy. Due to<br />
the extremely low internal resistance of<br />
ultracapacitors, the losses are reduced<br />
to a minimum and the energy transfer<br />
efficiency is maximized. Furthermore,<br />
ultracapacitors can be cycled more<br />
than 1 million times without experiencing<br />
substantial performance degradation.<br />
Additionally, ultracapacitors are<br />
environmentally friendly because they<br />
do not contain heavy metals and can<br />
therefore be recycled easily. Finally, and<br />
perhaps most importantly, ultracapacitors<br />
offer more than 10 times the power<br />
of batteries, which, when translated into<br />
functional application characteristics,<br />
Figure 3. Bombardier’s Mitrac Energy Saver trains use Ultracapacitor technology<br />
for energy storage.<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
www.powersystemsdesign.com<br />
<strong><strong>Power</strong>ing</strong> <strong>Freight</strong> & <strong>Transportation</strong><br />
Figure 4. Still’s Hybrid forklift equipped with Maxwell’s Ultracapacitors modules.<br />
provides higher performance in terms<br />
of acceleration of a vehicle, an essential<br />
goal of such applications.<br />
Ultracapacitors for Heavy <strong>Transportation</strong><br />
Applications<br />
Heavy transportation vehicles, such as<br />
trains trams and metros, place particular<br />
demands on energy storage devices.<br />
Such devices must be very robust and<br />
reliable displaying both long operational<br />
lifetimes and low maintenance requirements.<br />
Further, the devices must operate<br />
efficiently under harsh conditions<br />
including handling high peak currents,<br />
high duty cycle and frequent deep discharging.<br />
Maxwell Technologies, has<br />
addressed these issues with its BOOST-<br />
CAP ® HTM125 module for ultracapacitor-based<br />
braking energy recuperation<br />
and torque assist systems in transportation<br />
applications. Operating at 125V, the<br />
new module can store more energy per<br />
unit volume, deliver more power per unit<br />
volume and weight and perform longer<br />
than any other commercially available<br />
ultracapacitor solution.<br />
The HTM125 module is based on<br />
Maxwell’s MC power cell, rated at 3000<br />
Farads, which individually has a very low<br />
internal resistance, resulting in excellent<br />
efficiency during charging and discharging.<br />
Up to 12 modules may be linked in<br />
series to deliver as much as 1500V per<br />
system. One key factor in the energy<br />
storage systems is the thermal management.<br />
Using Maxwell's ultracapacitor<br />
modules, which incorporate efficient<br />
cooling systems, allows higher continuous<br />
currents up to 150A, and 750A as<br />
a peak (750A during 1 second @ 10%<br />
duty cycle), without compromising the<br />
reliability.<br />
Ultracapacitor products have been<br />
fully tested and qualified in light rail<br />
applications over many years. As an<br />
example, Bombardier's LRV (Light Rail<br />
Vehicle) prototype has been in passenger<br />
operation since 2003 in Germany<br />
and has recorded energy savings up to<br />
30% at around 300,000 load cycles per<br />
year. This success has now resulted in<br />
Bombardier delivering Mitrac Energy<br />
Saver trains utilizing ultracapacitor technology<br />
for energy storage for operation<br />
in the city of Heidelberg.<br />
Ultracapacitors for Heavy-Duty<br />
Equipment<br />
In the lifting, hoisting, and excavating<br />
equipment markets, typical characteristics<br />
of the energy storage demands<br />
include deep discharge cycling coupled<br />
with high duty cycle requirements.<br />
Cost is also a significant factor<br />
in the implementation of<br />
an energy storage option. In<br />
heavy duty equipments, the<br />
cost of the unit is outweighed<br />
by the durability, reliability and<br />
productivity factors. The initial<br />
cost of equipment is extremely<br />
high and this means that an<br />
elevated initial investment cost<br />
is returned faster for a higher<br />
performance, reliable and durable<br />
system.<br />
Maxwell’s heavy duty<br />
equipment solutions are the<br />
most flexible energy storage<br />
solution to power cranes,<br />
straddle-carriers, RTG, stackers,<br />
forklift, utility trucks, and<br />
other earth moving and mining<br />
equipments. With the help of<br />
the company’s ultracapacitor<br />
products, harbor crane<br />
manufacturers are providing<br />
innovative solutions to port<br />
authorities delivering savings<br />
of up to 30% on diesel consumption<br />
realized through both braking energy<br />
recovery and downsizing of diesel<br />
engines. The substantial reduction in<br />
terms of CO 2 emissions is also a significant<br />
advantage for the harbor's authorities<br />
in today’s climate where global<br />
warming and levels of gas emissions<br />
are becoming an increasingly greater<br />
concern.<br />
In lifting applications, studies have<br />
shown that new generations of forklifts<br />
equipped with Maxwell's ultracapacitor<br />
products can increase the autonomy<br />
and life of the equipment’s battery system<br />
by more than 25%, thereby reducing<br />
the cost of downtime and maintenance.<br />
The time for efficient and environmentally<br />
friendly energy storage and management<br />
has come and Maxwell’s<br />
ultracapacitor solutions have proven<br />
themselves to fulfil this requirement.<br />
These solutions are an essential part<br />
in today’s innovative, efficient hybrid<br />
system for public transportation and<br />
heavy industrial applications allowing an<br />
increase in power efficiency and a reduction<br />
in fuel consumption and global<br />
CO2 emissions.<br />
www.maxwell.com<br />
63
NEW PRODUCTS NEW PRODUCTS<br />
Compact Buck-Boost Regulators wth Ultra-Fast Switching<br />
Analog Devices has introduced one<br />
of the industry’s smallest buck-boost<br />
regulators—and the first to support<br />
switching frequencies at speeds up to<br />
2.5 MHz. <strong>Design</strong>ed to regulate voltages<br />
above and below the battery output<br />
voltage in portable electronics, ADI’s<br />
ADP2503 and ADP2504 step-up/stepdown<br />
dc-to-dc regulators incorporate<br />
a patent-pending architecture that<br />
delivers seamless mode transitions. The<br />
ultra-fast switching speed of the new<br />
regulators allows designers to use lowcost<br />
multilayer inductors that are half<br />
the size of other solutions. In addition,<br />
the total external component count has<br />
been reduced to three, resulting in a<br />
total PCB area of less than 13mm 2 and<br />
a height of less than 1mm, making the<br />
solution ideal for space-constrained<br />
applications such as wireless handsets,<br />
digital still cameras, portable audio<br />
players and USB-powered consumer<br />
and industrial devices.<br />
“Many lithium-battery-powered<br />
devices require voltage rails in the<br />
2.8-V to 3.6-V range for RF, audio, or<br />
motor applications. The ADP2503 and<br />
ADP2504 are ideal regulators to provide<br />
these voltages when board area and<br />
efficiency are important,” said Arcadio<br />
Leon, marketing director for portable<br />
power products, Analog Devices.<br />
The ADP2503 and ADP2504<br />
regulators are based on ADI’s new<br />
proprietary current-mode buck-boost<br />
architecture, achieving glitchless mode<br />
transitions and outstanding transient<br />
performance across line and load. This<br />
high level of output stability is critical for<br />
powering sensitive analog and digital<br />
circuitry. The devices also feature one of<br />
the industry’s lowest no-load quiescent<br />
current (Iq) levels - 38 µA in power-save<br />
mode - which extends stand-by time in<br />
portable electronics and/or increases<br />
the power budget for the inclusion of<br />
additional features. The proprietary<br />
H-Bridge buck-boost architecture<br />
improves the efficiency by more than<br />
10 percent versus legacy cascaded<br />
boost-buck architectures by reducing<br />
switching losses.<br />
The ADP2503 and ADP2504 operate<br />
at input voltages ranging from 2.3V and<br />
5.5V, which meets the requirements for<br />
single Li-Ion, Li-Ion polymer cell and<br />
multiple alkaline/NiMH cell applications.<br />
Fixed output voltages range from 2.8V<br />
to 5V.<br />
ADP2503 and ADP2504 are available<br />
now in sample quantities and come<br />
housed in a 10-lead 3-mm x 3-mm<br />
thin LFCSP package. The buck-boost<br />
regulators are priced at $1.40 per unit in<br />
1,000-unit quantities.<br />
electronica: Hall A4 Stand 159<br />
Step-Down Converter Draws Only 75uA Quiescent -<br />
Withstands 62V Transients<br />
33VIN, 62V Transient Protection Buck<br />
Regulator<br />
Linear Technology Corporation<br />
announces the LT3972, a 3.5A,<br />
33VIN step-down switching regulator<br />
with Burst Mode ® operation to keep<br />
quiescent current under 75uA. The<br />
LT3972 operates within a VIN range of<br />
3.6V to 33V, with overvoltage lockout<br />
protection against transients as high<br />
as 62V, making it ideal for load dump<br />
and cold-crank conditions commonly<br />
found in automotive applications. Its<br />
internal 4.6A switch can deliver up to<br />
3.5A of continuous output current at<br />
voltages as low as 0.79V. Its Burst Mode<br />
operation provides ultra-low quiescent<br />
current, well suited for applications<br />
such as automotive or telecom systems,<br />
which have always-on circuits and<br />
need to optimize battery life. Switching<br />
frequency is user programmable<br />
from 200kHz to 2.4MHz, enabling<br />
the designer to maximize efficiency<br />
while avoiding critical noise-sensitive<br />
frequency bands. Its 3mm x 3mm<br />
DFN-10 package (or thermally enhanced<br />
MSOP-10E), and high switching<br />
frequency keep external inductors and<br />
capacitors small, providing a compact,<br />
thermally efficient footprint.<br />
The LT3972 utilizes a high efficiency<br />
4.6A, 95mOhm switch, with the<br />
necessary boost diode, oscillator,<br />
control and logic circuitry integrated into<br />
a single chip. Low ripple Burst Mode<br />
operation maintains high efficiency<br />
at low output currents while keeping<br />
www.analog.com<br />
output ripple below 15mVPK-PK. Special<br />
design techniques used in the<br />
LT3972 enable high efficiency over<br />
a wide input voltage range, and the<br />
device’s current mode topology enables<br />
fast transient response and excellent<br />
loop stability. Other features include<br />
external synchronization (from 250kHz<br />
to 2MHz), a power good flag and softstart<br />
capability.<br />
Pricing for the LT3972EDD and<br />
LT3972EMSE starts at $4.25 and $4.35<br />
each, respectively for 1,000-piece<br />
quantities. The LT3972IDD and<br />
LT3972IMSE are guaranteed to operate<br />
from a -40°C to 125°C operating<br />
junction temperature, priced at $5.10<br />
and $5.22 each, respectively in<br />
1,000-piece quantities. All versions are<br />
available from stock.<br />
electronica: Hall A4 Stand 538<br />
Hall A5 Stand 568<br />
www.linear.com<br />
New Surface mount & radial leaded inductors reduce EMI<br />
Murata <strong>Power</strong> Solutions has<br />
enhanced its radial lead and toroidal<br />
surface-mount inductor portfolios<br />
with the addition of four new ranges<br />
of RoHS compliant components. The<br />
introductions comprise over 50 new part<br />
numbers that reinforce Murata <strong>Power</strong><br />
Solutions’ reputation as a provider of<br />
industry-leading magnetic products.<br />
The 1500 and 1900R series are<br />
general purpose radial leaded inductors<br />
suitable for providing filtering in low<br />
to medium current applications such<br />
as those found in power supplies.<br />
The 4200 and 4300 series of toroidal<br />
surface-mount inductors meanwhile are<br />
designed for use in switching AC/DC<br />
power supplies and DC/DC converters.<br />
Their low-profile design makes<br />
them ideal for use in designs where<br />
component height is restricted.<br />
Both the 1500 and 1900R series offer<br />
low DC resistance. The 1500 series is<br />
available with current ratings up to 16.2A<br />
IDC and inductance values that range<br />
from 1.0µH to 1.0mH. The 1900R series<br />
is rated to 7.8A IDC with inductance<br />
values of between 4.7µH and 100mH.<br />
Custom parts are available on request.<br />
Both ranges are supplied in cartons<br />
of 40, are fully compatible with RoHS<br />
soldering systems and have backward<br />
compatibility to Sn/Pb solder processes.<br />
Operating free air temperature range is<br />
-40ºC to +85ºC.<br />
xprinc th driv<br />
automotiv.tlmatics.snsors.infotainmnt.scurity.<br />
The 4200 and 4300 series toroidal<br />
surface-mount inductors have<br />
compact overall dimensions with a<br />
maximum overall height of less than<br />
10mm. Both ranges utilise UL94 V-0<br />
package materials, are pick & place<br />
compatible and meet J-STD-020C<br />
reflow requirements with backward<br />
compatibility to Sn/Pb soldering<br />
systems. The toroidal construction of<br />
the new inductors aids design engineers<br />
by helping minimize EMI issues. The<br />
4200 series has a current rating of up to<br />
15.4A IDC and a choice of inductance<br />
values between 1.27µH and 17.6µH.<br />
The 4300 series comprises parts with<br />
inductance values ranging from 2.1µH<br />
to 4.0µH and a maximum current rating<br />
of 22.4A IDC. Operating temperature for<br />
both ranges is -40ºC to +125ºC.<br />
electronica: Hall B2 Stand 431<br />
www.murata-ps.com<br />
64 <strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
www.powersystemsdesign.com<br />
65
NEW PRODUCTS NEW PRODUCTS<br />
MOSFETs for Efficiency, Reliability, and Safety in<br />
Lighting and SMPS<br />
STMicroelectronics has increased the<br />
ruggedness, switching performance and<br />
efficiency of power MOSFETs for lighting<br />
ballasts, where they are used in the PFC<br />
and Half Bridge sections, as well as in<br />
switching power supplies. The use of<br />
innovative SuperMESH3 TM technology<br />
with lower on-resistance guarantees<br />
that higher efficiency is obtained.<br />
Additionally, due to their superior dv/dt<br />
performance and higher breakdownvoltage<br />
margin, these new devices will<br />
provide enhanced reliability and safety.<br />
The first SuperMESH3 devices<br />
introduced are the 620V STx6N62K3,<br />
which will be followed by the<br />
STx3N62K3, also at 620V, as well as<br />
the 525V STx7N52K3 and STx6N52K3.<br />
The savings in on-resistance enabled<br />
by SuperMESH3 reduce R DS(on) in<br />
DPAK packages to 1.28 Ohms in the<br />
STD6N62K3 at 620V and 0.98 Ohms<br />
in the STD7N52K3 at 525V boosting<br />
operating efficiency in applications<br />
such as low-energy lamp ballasts. The<br />
new technology also reduces reverserecovery<br />
time (Trr), gate charge, and<br />
intrinsic capacitance, leading to<br />
improved switching performance and<br />
enabling higher operating frequencies.<br />
As a further advantage of<br />
ST’s SuperMESH3 technology, which<br />
combines strip topology with an<br />
optimized vertical structure, the new<br />
devices also exhibit one of the best-inclass<br />
dv/dt behaviors. This translates<br />
into increased reliability and safety in<br />
lighting and other consumer electrical<br />
applications. All SuperMESH3 devices<br />
are 100% avalanche tested, and also<br />
incorporate zener protection to deliver<br />
all-round robust performance.<br />
By achieving the lowest on-resistance<br />
per area among comparable highvoltage,<br />
fast-recovery technologies,<br />
SuperMESH3 allows the STx6N62K3,<br />
STx7N52K3, STx3N62K3 and<br />
STx6N52K3 to use smaller packages<br />
such as DPAK, than similarly rated<br />
alternatives. This saves footprint and<br />
board size, yet matches the switching<br />
and thermal performance of physically<br />
larger devices.<br />
The STx6N62K3 is available in<br />
IPAK, DPAK, TO-220, and TO-220FP<br />
packages, priced from $0.62 for 1000<br />
pieces.<br />
The STx3N62K3 at 2.5 Ohms will<br />
be available in IPAK, DPAK, D2PAK,<br />
TO-220 and TO-220FP packages.<br />
The STx7N52K3 at 0.98 Ohms will<br />
be introduced in DPAK, D2PAK,<br />
TO-220, and TO-220FP packages<br />
and the STx6N52K3 at 1.2 Ohms will<br />
be available in DPAK and TO-220FP<br />
packages. These lines will enrich the<br />
620 and 520V portfolio of SuperMESH3<br />
products, which will be in volume<br />
production by Q4 2008.<br />
electronica: Hall A5 Stand 207<br />
Hall A5 Stand 159<br />
www.st.com<br />
Super Junction <strong>Power</strong> MOSFETs Improve Efficiency and<br />
Switching Speed in Applications to 600V<br />
White <strong>Power</strong> SMD LEDs utilizing InGaN/TAG on Sapphire<br />
Technology<br />
Vishay Intertechnology has released<br />
the industry’s first high-intensity white<br />
power SMD LEDs in the CLCC-6 and<br />
CLCC-6 flat ceramic packages to offer<br />
InGaN/TAG on sapphire technology for<br />
high optical power from 2240mcd to<br />
5600mcd.<br />
<strong>Design</strong>ed to reduce costs in highvolume<br />
applications, the new VLMW63..<br />
series features the CLCC-6 package and<br />
a low thermal resistance to 50k/W, while<br />
the VLMW64 series in the CLCC-6 flat<br />
package offers a low thermal resistance<br />
of 40k/W and an ultra-low profile of<br />
0.9mm.<br />
With compact footprints of 3.3mm<br />
by 3.4mm, the ceramic packages of<br />
the LEDs allow the additional current<br />
drive for a maximum light output while<br />
maintaining a high service life of up to<br />
50,000 hours, making them ideal light<br />
sources in space-limited applications<br />
where thermal management is a key<br />
consideration.<br />
The devices are optimized for<br />
backlighting and illumination in<br />
automotive and transport, consumer,<br />
and general applications. Typical end<br />
products include flashes for cameras;<br />
emergency lighting; and automotive<br />
instrument panels and exterior lighting,<br />
such as brake lights and turn signals.<br />
The LEDs offer a typical luminous flux<br />
of 11000 mlm and optical efficiency<br />
up to 30 lm/W. The devices feature a<br />
luminous intensity ratio per package unit<br />
of IV max/IV min ≤1.6, forward voltage<br />
up to 4.3V and 60° half-intensity angle.<br />
The VLMW63 and VLMW64 LEDs<br />
are compatible with IR-reflow solder<br />
processes, in accordance with CECC<br />
00802 and J-STD-020C. Preconditioned<br />
according to JEDEC Level 4 standards,<br />
the CLCC-6 and CLCC-6 flat packages<br />
are lead (Pb)-free and RoHS-compliant.<br />
The devices are automotive qualified<br />
AEC-Q101 and offer an ESD-withstand<br />
voltage up to 2kV in accordance with<br />
JESD22-A114-B.<br />
Samples and production quantities of<br />
the new VLMW63 and VLMW64 highintensity<br />
white power SMD LEDs are<br />
available now.<br />
electronica: Hall A5 Stand 143<br />
www.vishay.com<br />
Featuring 20A (TK20A60U), 15A<br />
(TK15A60U) and 12A (TK12A60U)<br />
current ratings, the three new DTMOS<br />
II power MOSFETs are ideal for switch<br />
The new DTMOS II family brings<br />
together the latest version of<br />
Toshiba’s Super Junction MOSFET<br />
technology with the company’s optimised experience the drive<br />
mode power supplies, lighting ballasts, cell design. The result is a range of<br />
motor drives and other applications<br />
requiring high efficiency, high-speed<br />
devices that combine minimised<br />
on resistance and gate charge – a<br />
automotive.telematics.sensors.infotainment.security.<br />
switching. Respective RDS(on) and Qg key factor in switching speed – with<br />
ratings of 0.19Ω and 27nC, 0.3Ω and high levels of ruggedness. All of the<br />
17nC, and 0.4Ω and 14nC mean that the new MOSFETs, for example, provide<br />
devices have the industry’s lowest ‘Qg * industry-leading avalanche durability<br />
Toshiba Electronics Europe has RDS(on)’ at comparable Current class. and reverse recovery characteristics.<br />
announced the first products from its All of the new devices are supplied in<br />
electronica: Hall A5 Stand 476<br />
new DTMOS II family of rugged, highefficiency,<br />
high-speed power MOSFETs.<br />
the compact TO220SIS ‘smart isolation’<br />
package that offers full pin compatibility<br />
www.toshiba-components.com<br />
The new 600V power MOSFETs<br />
with existing TO-220 devices, while<br />
combine a very low on resistance (RDS(on)) delivering a 13.5% reduction in PCB<br />
and reduced gate charge (Qg) to deliver<br />
an RDS(on) x Qg ‘figure of merit’ that is<br />
15% lower than the company’s existing<br />
DTMOS I range and 68% lower than<br />
conventional MOSFETs.<br />
66<br />
mounting height. This package uses<br />
copper connections rather than<br />
aluminium bonding wires, which leads to<br />
improved current and lower resistance<br />
ratings and aids heat dissipation.<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008<br />
get the whole picture<br />
electronica automotive: a unique industry gathering for leading international manufacturers, prominent experts<br />
and decision-makers in automotive electronics. Special highlight: the electronica automotive conference<br />
(Nov. 10–11, 2008), which focuses on the world’s latest topics and trends and the challenges of the future and<br />
promotes www.powersystemsdesign.com<br />
the transfer of know-how and networking at the highest level. www.electronica.de/automotive.<br />
electronica 2008<br />
automotive<br />
23rd world’s leading trade fair<br />
67<br />
Be sure to visit the concurrent trade fair www.hybridica.de<br />
electronica automotive conference<br />
Strategy + Technology + Networking<br />
www.electronica.de/automotive<br />
New Munich Trade Fair Centre<br />
November 11–14, 2008
68<br />
NEW PRODUCTS<br />
All-in-One Solution for Programmable Motion Control<br />
Crouzet has introduced the Motomate<br />
Brushless Motor featuring compact size,<br />
convenience and easy programmability.<br />
<strong>Design</strong>ed with an integral controller,<br />
the new motor provides an all-inone<br />
solution for a wide range of<br />
applications where programmable<br />
movement of simple mechanisms is<br />
required. Typical uses include control of<br />
automatic doors and door lifts, access<br />
barriers, rolling advertisement boards,<br />
intelligent conveyor systems, robotic<br />
swimming pool cleaners, and machine<br />
subassemblies.<br />
Motomate incorporates a Crouzet<br />
built-in Milleneum2 controller, brushless<br />
motor drive, motor, and gearbox<br />
in a compact 2-1/2” x 6” package.<br />
The brushless motor features a high<br />
motor efficiency of 90% compared to<br />
asynchronous motors of only 40%,<br />
and a surprisingly high starting torque<br />
given its compact size. With the power<br />
electronics incorporated directly inside<br />
the motor, the need for an external<br />
speed controller is eliminated, optimizing<br />
space for tight product designs.<br />
By combining the controller, drive,<br />
motor and gearbox into a single unit, the<br />
Motomate offers complete compatibility<br />
and convenience. “If you buy these four<br />
components separately, you have to get<br />
them to work with each other,” explains<br />
Jim McNamara, Crouzet Application<br />
Engineer. “The Motomate eliminates all<br />
that by providing a small, neat package<br />
where all components are already<br />
integrated and compatible.”<br />
Motomate is available with a motor<br />
range of 30 or 80 Watts in several<br />
configurations to meet all types<br />
of required movement. Motomate<br />
produces up to 0.3N.m in the direct<br />
drive configuration, up to 3.5N.m in<br />
the right angle configuration, and up to<br />
30N.m in the planetary configuration<br />
Rugged & Reliable Automotive-Qualified 600V ICs<br />
International Rectifier has introduced<br />
the AUIRS212xS family of rugged<br />
600V, single channel high-side driver<br />
ICs for low-, mid-, and high-voltage<br />
automotive applications including<br />
general purpose automotive drives,<br />
high-voltage actuators and fuel-efficient<br />
direct injection systems.<br />
Qualified to AEC-Q100 standards,<br />
the AUIRS2123S and AUIRS2124S high<br />
Specifications<br />
speed power MOSFET and IGBT drivers<br />
offer a gate drive supply range from 10V<br />
to 20V. The output drivers feature a highpulse<br />
current buffer stage designed for<br />
minimum driver cross-conduction while<br />
the floating channel can be used to drive<br />
N-channel power MOSFETs or IGBTs in<br />
the high-side configuration operating up<br />
to 600V. Both devices feature negative<br />
voltage spike (Vs) immunity to protect<br />
the system against catastrophic events<br />
during high-current switching and short<br />
circuit conditions.<br />
<strong>Design</strong>ed specifically for automotive<br />
applications, the new ICs use a<br />
proprietary latch immune CMOS<br />
technology featuring exceptional<br />
negative Vs immunity to deliver the<br />
ruggedness and reliability essential for<br />
harsh environments and automotive<br />
(custom torques are also available).<br />
Other important characteristics include<br />
analog output and internal torque<br />
(current) sensing capabilities for<br />
increased application flexibility. Intuitive<br />
programming with graphical function<br />
blocks allow easy programming of<br />
acceleration and deceleration in forward<br />
or backward motion with controlled time<br />
and speed ramps. Reprogramming is<br />
easily accomplished by using a PC or<br />
a removable memory module. Sensors<br />
and actuators can be easily added to<br />
the controller’s inputs/outputs as the<br />
need for expansion is required.<br />
Motomate is designed to provide a<br />
long service life of 20,000 hours and<br />
continual torque force even under<br />
locked rotor conditions (BTN model<br />
only). The unit’s 24 VDC supply voltage<br />
offers added security in case of accident<br />
or vandalism, and a battery supply<br />
option provides standard or backup<br />
energy for on-board systems or critical<br />
medical equipment.<br />
www.crouzet-usa.com<br />
under-the-hood applications.<br />
The AUIRS2123S features output<br />
signals in phase with the input signal<br />
while the AUIRS2124S features output<br />
signals out of phase with the input<br />
signal. Both devices provide undervoltage<br />
lockout and CMOS Schmitttriggered<br />
inputs with pull-down.<br />
The new ICs utilize IR’s advanced<br />
high-voltage IC process which<br />
incorporates next-generation highvoltage<br />
level-shifting and termination<br />
technology to deliver superior electrical<br />
over-stress protection and higher field<br />
reliability.<br />
More information is available at the<br />
International Rectifier website at http://<br />
www.irf.com/whats-new/nr080904.html<br />
Available in an 8-lead SOIC package,<br />
production quantities are available<br />
immediately. The automotive- qualified<br />
devices are lead-free and RoHS<br />
compliant.<br />
electronica: Hall A5 Stand 343<br />
www.irf.com<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
Texas Instruments<br />
Linear Technology<br />
Fairchild Semiconductor<br />
Magnetics<br />
Microchip Technology<br />
Advertisement<br />
TI’s three new smart battery management<br />
integrated circuits improve measurement and<br />
protection of multi-cell, lithium-based batteries<br />
used in power tools, e-bicycles, and portable<br />
medical and test equipment. The battery<br />
management controller bq78PL114 provides<br />
complete lithium battery system control,<br />
monitoring and safety functions for 4-series cells.<br />
By leveraging the <strong>Power</strong>LAN communications<br />
interface, a designer can combine multiple<br />
bq76PL102 dual-cell monitor devices with this<br />
Linear Technology Corporation announces<br />
the LT3080, a 1.1A 3-terminal LDO that may<br />
be easily paralleled for heat spreading and<br />
is adjustable with a single resistor. This new<br />
architecture regulator uses a current reference to<br />
allow sharing between multiple regulators with<br />
a small length of PC trace as ballast, enabling<br />
multi-amp linear regulation in all surface-mount<br />
systems without heat sinks.<br />
The LT3080 achieves high performance<br />
without any compromises. Featuring wide input<br />
Gain a Highly Efficient and Flexible Pointof-Load<br />
<strong>Power</strong> Conversion Solution with<br />
Fairchild’s Digital <strong>Power</strong> Controllers<br />
These digital power controllers combine<br />
digital loop control with highly integrated power<br />
management capabilities to offer flexible, easyto-design<br />
power delivery solutions. These<br />
controllers address a wide variety of complex<br />
power system requirements found in applications<br />
Magnetics is pleased to announce the<br />
addition of XFLUX TM , a distributed air gap 6.5%<br />
SiFe material, to our existing powder core line. A<br />
true high temperature material, with no thermal<br />
aging, XFLUX offers lower losses than powder<br />
iron cores and superior DC Bias performance.<br />
XFLUX cores are ideal for low and medium<br />
frequency chokes where inductance at peak<br />
is critical. One of the many challenges facing<br />
designers of high power circuits is maintaining<br />
Microchip Offers Free Field Oriented Control<br />
Algorithm for New Low-Cost Motor Control<br />
Digital Signal Controllers<br />
Microchip announces 10 new 28- and 44-pin<br />
16-bit Digital Signal Controllers (DSCs) for motor<br />
control designs requiring increased memory,<br />
performance, or enhanced peripherals, while<br />
obtaining cost and size savings by using lower<br />
pin-count devices. Additionally, Microchip<br />
controller to create a smart battery solution for<br />
up to 12 rechargeable cells. Another degree of<br />
integration, safety and protection to multi-cell<br />
applications is added with bq77PL900, the new<br />
lithium-based battery protector and analog front<br />
end for 5- to 10-cell battery systems.<br />
See: www.ti.com/bq78pl114 and www.ti.com/<br />
bq77pl900.<br />
Visit Texas Instruments at electronica: hall A4,<br />
booth 420.<br />
voltage capability from 1.2V to 40V, it has a low<br />
dropout voltage of only 300mV at full load. The<br />
output voltage is adjustable, spanning a wide<br />
range from 0V to 40V, and the on-chip trimmed<br />
reference achieves high accuracy of +-1%. The<br />
wide V IN & V OUT capability, tight line and load<br />
regulation, high ripple rejection, low external<br />
parts count and parallel capability make it ideal<br />
for modern multi-rail systems.<br />
www.linear.com<br />
such as datacom equipment, servers, FPGA<br />
power supplies, DDR memory power supplies<br />
and industrial control equipment.<br />
http://www.fairchildsemi.com/products/<br />
digitalpower/index.html<br />
inductance in the power choke at maximum<br />
load. XFLUX is the cost-effective solution to<br />
getting enough inductance in a reasonable size<br />
package.<br />
Seven toroid sizes (60 permeability) are<br />
currently available. Outside diameters range<br />
in size from 21mm to 47mm. New sizes and<br />
permeabilities will be added in the future.<br />
www.mag-inc.com<br />
announced five motor control software solutions<br />
for: <strong>Power</strong> Factor Correction (PFC), sensorless<br />
Field Oriented Control (FOC) of a PMSM motor,<br />
sensorless FOC of an ACIM motor, sensorless<br />
control of a BLDC motor using Back EMF<br />
filtering and sensorless BLDC control with Back-<br />
EMF Filtering Using a Majority Function.<br />
www.microchip.com/DSCMOTOR<br />
Alpha & Omega Semiconductor ................................................. 6<br />
Analog Devices ......................................................................... 7<br />
Analog Devices ......................................................................... 65<br />
Ansoft ...................................................................................... 13<br />
APEC ........................................................................................ 71<br />
Bergquist ................................................................................. 15<br />
C&K Components .................................................................... 12<br />
Cirrus Logic ............................................................................. 21<br />
Coilcraft ................................................................................... 11<br />
Crouzet ..................................................................................... 64<br />
Digi-Key ..................................................................................... 1<br />
Digi-Key ...................................................................................... 6<br />
electronica .........................................................................65-60<br />
EpowerPack ............................................................................ 43<br />
Ericsson <strong>Power</strong> Modules ....................................................... 19<br />
Fairchild Semiconductor ........................................................C2<br />
Fairchild Semiconductor ..................................................... 24,37<br />
Gresham <strong>Power</strong> Electronics ....................................................... 8<br />
International Rectifier ............................................................C4<br />
International Rectifier ............................................................... 16<br />
Intersil ......................................................................................C3<br />
isuppli ....................................................................................... 18<br />
ITWPaktron ............................................................................. 10<br />
Kienbaum ................................................................................ 57<br />
Kunze ....................................................................................... 60<br />
LEM .......................................................................................... 31<br />
Lineage <strong>Power</strong> .......................................................................... 12<br />
Linear Technology ............................................................... 5,40<br />
Linear Technology ..................................................... 29,46,52,65<br />
Lti REEnergy ............................................................................... 6<br />
www.powersystemsdesign.com<br />
Companies in this Issue<br />
NEW PRODUCTS<br />
Company Page Company Page<br />
Please note: Bold---companies advertising in this issue<br />
Magnetics ................................................................................ 23<br />
Maxwell Technologies ........................................................... 6,61<br />
Maxwell Technologies ............................................................ 27<br />
Micrel ....................................................................................... 25<br />
Microsemi ................................................................................. 12<br />
Murata ...................................................................................... 68<br />
National Semiconductor ........................................................ 17<br />
Ohmite ....................................................................................... 9<br />
On Semiconductor ................................................................... 68<br />
Philips Lumileds ....................................................................... 41<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> Worldwide ....................................... 44<br />
<strong>Power</strong>Pack .............................................................................. 70<br />
Raztec Sensors ........................................................................ 54<br />
Ridley Engineering ....................................................... 32,33,47<br />
Ridley Engineering .................................................................... 20<br />
Sharp Microelectronics Europe ................................................ 28<br />
SMP .......................................................................................... 14<br />
SolFocus .................................................................................... 6<br />
STMicroelectronics ................................................................ 8,66<br />
Texas Instruments .................................................................... 2<br />
Texas Instruments .................................................................... 26<br />
Toshiba Electronics .................................................................. 66<br />
TTI ............................................................................................ 12<br />
Tyco Electronics ..................................................................... 51<br />
Tyco Electronics ....................................................................... 55<br />
Vicor Europe .......................................................................... 6,58<br />
Vicor/Picor ................................................................................ 30<br />
Voltage Multipliers .................................................................. 10<br />
Waseda University ...................................................................... 8<br />
71
72<br />
Whichever Way the Wind Blows…<br />
I’m getting a continuous flow of news<br />
reports, particularly in wind power<br />
with photovoltaic technology on the<br />
increase, as well as the higher efficiency<br />
power devices and modules now constantly<br />
hitting the market. It just shows<br />
the great change we are seeing in the<br />
mindset of the economy. Now, power and<br />
power generation in particular, is getting<br />
the attention it deserves. The ‘penny has<br />
finally dropped’ with the gate keepers<br />
and purse holders, that this really is a<br />
good thing. It also presents an investment<br />
opportunity for those with funds available.<br />
Ericsson has unveiled its latest<br />
energy-optimized radio base station<br />
site concept, a research project for a<br />
pioneering wind-powered Tower Tube,<br />
working with Vertical Wind AB and Uppsala<br />
University in Sweden. It harnesses<br />
wind power via a four-blade turbine with<br />
five-meter blades vertically attached<br />
to the tower. The vertical rotor blades<br />
Belgian offshore wind farm - Thornton<br />
Bank.<br />
Reported by Cliff Keys, Editor-in-Chief, PSDE<br />
work silently and minimize the load on<br />
the tower during operation. Trials will be<br />
conducted to determine if the design<br />
can enable low-cost mobile communication,<br />
with reduced impacts on both<br />
the local and global environment.<br />
Eclipse Energy has promised the<br />
world's “most efficient" wind development,<br />
after gaining permission to build<br />
the UK's first commercial-scale offshore<br />
wind farm to be based on giant 5MW<br />
turbines. The Ormonde Wind Farm in<br />
the Irish Sea will use REpower wind<br />
turbines, as demonstrated at the twoturbine<br />
Beatrice wind farm off the eastern<br />
Scottish coast, with plans to use 30<br />
units to generate a total of 150MW.<br />
The project will also have a platform<br />
hosting three 30MW gas turbines to<br />
feed from the two Ormonde gas fields<br />
underneath - delivering power during<br />
periods of light wind.<br />
REpower has also completed the pilot<br />
phase for Belgian offshore wind farm<br />
Thornton Bank, having now assembled<br />
the rotor for the sixth turbine. The company<br />
C-<strong>Power</strong> is the contracting party<br />
for the project which is located approximately<br />
30 km from Zeebrugge in a water<br />
depth of some 25 metres. C-<strong>Power</strong>’s<br />
plan is to develop the Thornton Bank<br />
wind farm to a total of 300 MW.<br />
The Finnish government has agreed<br />
to construct wind power plants over the<br />
next decade. Indications are that the<br />
aim is to generate about 2000 MW of<br />
wind power by the year 2020 requiring<br />
about 1,000 turbines.<br />
The proposal calls for development<br />
of wind parks in key catchment areas<br />
such as coastlines, to accommodate the<br />
large number of turbines needed. The<br />
proposal is part of government's climate<br />
and energy strategy that is currently<br />
under consideration.<br />
It’s very encouraging to see these<br />
projects finally coming to fruition.<br />
www.powersystemsdesign.com/<br />
greenpage.htm<br />
<strong>Power</strong> <strong>Systems</strong> <strong>Design</strong> October 2008
Features<br />
Part Number<br />
V BUS<br />
V S -COM<br />
-V S<br />
Rugged, Reliable<br />
Motor Control - by <strong>Design</strong><br />
Single-<br />
Phase<br />
Protect Against Catastrophic Events With IR’s High Voltage ICs<br />
3-Phase<br />
Negative Vs<br />
Immunity<br />
V S Undershoot<br />
Integrated<br />
Bootstrap<br />
Greater<br />
protection<br />
against a<br />
“negative Vs”<br />
event<br />
t t<br />
Advanced<br />
Input Filter<br />
IRS260xD X X X X<br />
IRS2336D X X X X<br />
Current<br />
Sense OPA<br />
IRS233xD X X X X X<br />
Ground Fault<br />
Detection<br />
DC Bus<br />
Sensing<br />
IRS26302D X X X X X X<br />
IRS26310DJ X X X X X<br />
Hall A5,<br />
Stand 560<br />
For more information call +33 (0) 1 64 86 49 53 or +49 (0) 6102 884 311<br />
or visit us at www.irf.com<br />
Brake/PFC<br />
Drive<br />
<strong>Design</strong>ed and characterized to be<br />
tolerant to repetitive negative Vs<br />
transient voltage<br />
Characterized to withstand short<br />
circuit events<br />
Tolerant to large dV/dt<br />
Integrated bootstrap functionality<br />
Advanced input fi lter<br />
Fully operational up to 600 V<br />
THE POWER MANAGEMENT LEADER