Powering Freight & Transportation - Power Systems Design

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
Special Report – Powering Freight & Transportation
Design Tips
Design Tips
ISSN: 1613-6365

Ultra-Low Power LDOs
150mA, 500nA I Q Regulators for MCU-Based Applications
Applications
– TI MSP430-based applications
and other microcontrollers
– Power rails with programming
mode
– Wireless handsets and other
low-power, battery-powered
products
Features
– Low I Q : 500nA (typ)
– Available in fixed output
voltages from 1.5V to 4.2V using
innovative factory EPROM
programming
– Available in adjustable versions
from 1.22V to 5.25V
– V SET pin toggles output voltage
between two factory-programmed
voltage levels
– Stable with a 1.0µF ceramic
capacitor
– Logic level compatible enable pin
– Price: $0.65 (1k)
Power
Management
TPS780xx
2mm x 2mm
150mA
High-Performance Analog >>Your Way and the platform bar are trademarks of Texas Instruments. 2252A1 © 2008TI
GND
High-Performance Analog>>Your Way
V CC
I/O
Microcontroller
GND
TI’s TPS780xx LDOs with dual-level voltage output for low-power,
battery-powered devices consume only 500nA of quiescent current.
The LDOs implement dynamic voltage scaling (DVS), using a voltage
select (V SET ) pin to allow switching between two voltage levels to
customize and cut power consumption.
Device
VIN (V)
IOUT (mA)
VOUT (V)
IQ (µA) Package
Price
(1k)*
TPS780xx 2.2 - 5.5 150 1.22 - 5.25 500nA TSOT-23, SON $0.65
TPS781xx 2.2 - 5.5 150 1.22 - 5.25 1 TSOT-23, SON $0.50
TPS797xx 1.8 - 5.5 10 1.25 - 4.9 1.2 SC70 $0.34
TPS715xx 2.5 - 24 50 1.2 - 15 3.2 SC70 $0.34
TPS715Axx 2.5 - 24 80 1.2 - 15 3.2 SON $0.44
* Suggested resale price in U.S. dollars in quantities of 1,000.
Visit us at electronica Booth A4.420
www.ti.com/tps780xx-e or call toll free:
00800-ASKTEXAS (00800 275 83927)
or international: +49 (0) 8161 80 2121
Get Evaluation Modules, Samples and Power Management Selection Guide
Dilbert – 72
Viewpoint
Engineering Rules – OK? ...........................................................................................................................................................................................4
Industry News
Digi-Key Corporation and Alpha & Omega Semiconductor Sign Global Distribution Agreement ............................................................................6
Vicor Strengthens European Team ............................................................................................................................................................................6
SolFocus Completes CPV Installation at ISFOC’s 3MW Solar Power Plant .............................................................................................................6
General Manager Boosts Management Team at Gresham .......................................................................................................................................8
High-Performance Two-Wheel Inverted Pendulum Robot via R&D Cooperation .....................................................................................................8
LTi REEnergy Selects Maxwell Technology BOOSTCAP ® Ultracapacitors for Backup Power in Wind Turbines ....................................................10
Microsemi Appoints Bel Lazar Senior VP of Operations .........................................................................................................................................12
TTI Signs Pan-European Franchise Deal with C&K Components ...........................................................................................................................12
Lineage Power Appoints Global VP of OEM Sales .................................................................................................................................................12
Power Events.................................................................................................................................................................................................12
Energy-Efficient Chokes for Transportation ............................................................................................................................................................14
Optimized Power Processing and Energy Efficiency, By Oleg Khaykin, International Rectifier ..............................................................................16
Portable Power-Management Market Throws the Switch, By Marijana Vukicevic, iSuppi .....................................................................................18
Design Tips
Power Supply Control Design Tools – Part VI, By Dr. Ray Ridley, Ridley Engineering ............................................................................................20
On The Road
Fairchild Semiconductor, Texas Instruments, Sharp Microelectronics, Linear Technology, Vicor/Picor, Reported by Cliff Keys, Editor-in-Chief, PSDE .....24
Cover Story
On The Right Track, By Michel Ghilardi & Marc Schaerrer, LEM SA .......................................................................................................................31
Solar Power
Solar Power Shines! Part II, By Alfred Hesener, Fairchild Semiconductor ..............................................................................................................37
Lighting
Avoiding Current Spikes with LEDs, By Pat Goodman, Philips Lumileds ...............................................................................................................41
Special Report: Powering Freight & Transportation
Transport and Automotive Appliances Benefit from Multiphase Boosters, By Bruce Haug & Tick Houk, Linear Technology ...............................46
Electric Vehicle Battery Monitoring, By Warren Pettigrew, Raztec Sensors............................................................................................................52
Circuit Protection for Safer Automotive Electrical Architectures, By Guillemette Paour, Tyco Electronics .............................................................55
One Step Closer to the Birds, By Marco Panizza, Vicro Europe .............................................................................................................................58
Progressing Freight and Transportation, By Sven Baechtiger, Maxwell Technologies............................................................................................61
New Products.................................................................................................................................................................................................64
Whichever Way the Wind Blows, Reported by Cliff Keys, Editor-in-Chief, PSDE ...................................................................................................72
Member
Arnold Alderman
Heinz Rüedi
Marion Limmer
Dr. Reinhold Bayerer
Dr. Leo Lorenz
Davin Lee
Eric Lidow
Tony Armstrong
Hans D. Huber
Power Systems Design Europe Steering Committee Members
Representing
Anagenesis
CT-Concept Technology
Fairchild Semiconductor
Infineon Technologies
Infineon Technologies
Intersil
International Rectifier
Linear Technology
LEM
Member
Andrew Cowell
Michele Sclocchi
Kirk Schwiebert
Christophe Basso
Balu Balakrishnan
Paul Greenland
Uwe Mengelkamp
Peter Sontheimer
Representing
Micrel
National Semiconductor
Ohmite
On Semiconductor
Power Integrations
Semtech
Texas Instruments
Tyco Electronics

VIEWPOINT
Engineering Rules – OK?
In this issue we have brought
together the rather adventurous
theme of ‘Powering Freight and
Transportation’. With the proliferation
of power electronics in traction, mobility
and freight, we thought we’d look at
the relatively unexplored area of our
technology. The feature includes the
power and control of systems which give
mobility to freight, goods and people, in
fact anywhere where electronics is used
to make our everyday lives easier; from
the supermarket bands that transport
our shopping at the checkout, on
through escalators, golf carts, disabled
vehicles, stair-lifts and of course electric
locomotives. A huge power saving
opportunity! I find it really exciting that
when we take off the blinkers from our
individual ‘comfort zones’, we find that
our world of power and its conservation
is to be found everywhere.
Britain languishes near the bottom
of the European renewables league
table which is a very sad state of affairs.
The International Energy Agency
said Britain’s renewables strategy is
“ineffective” and “very expensive”. The
agency’s new report ranks Britain 31st
out of 35 countries - “including all the
major industrial nations such as the
US, Germany and China” - in its green
energy cost league with ‘renewables
effectiveness’ a ridiculous 3%. The
government seems to favour nuclear
and coal, rather than to take a more
environmentally-sensible approach.
Several European countries are now
giving priority access to the grid for low
carbon generated energy, but in the UK
at times there are reports of situation
where fully working wind farms are
turned off because a fossil fuel plant has
priority access to the grid. When can we
get a European government policy that
makes good sense for the population
and the environment rather than
watered-down policies which look to be
an unhealthy compromise to satisfy the
powerful career-politicians and influential
business leaders?
A piece of breaking news for our
colleagues in North America: Power
Systems Design has just announced the
launch of its North American magazine,
Power Systems Design North America,
which is due to hit the streets in the
January/February issue timeframe. I will
be the editor for the magazine and look
forward to also serving our colleagues
in the US. Naturally I’ll try to get the best
reports of both regions to our expanded
power community.
I am in the midst of my US visit to
see the major players here and to gain
for our readers an insight into what’s
happening here and what’s ‘in the pipe’
preparing for launch.
We soon have the gruesome-but-fun
experience of electronica. Many of us
are finalizing last-minute presentations,
product demos or trade stands for this
huge event, one of the biggest and most
comprehensive electronics shows in the
world. With an expected visitor profile
of 80,000+, we should all be kept pretty
busy. As always I’ll pull together an
overview of what I see there for those of
you who are too busy to come.
Finally, I’d like to thank you for your
continued support, healthy feedback and
the all-important design features and
articles that make our magazine a living
proof that the power industry is a vibrant
and growing community, of which we
should all be rightly proud. Check out the
Dilbert fun-strip on the GreenPage. Only
our engineers will save the environment.
All the best!
Editor-in-Chief, PSDE
Cliff.Keys@powersystemsdesign.com
Power Systems Design October 2008

INDUSTRY NEWS
Digi-Key Corporation and Alpha & Omega
Semiconductor Sign Global Distribution Agreement
Digi-Key Corporation and Alpha & Omega
Semiconductor, Inc. (AOS) have announced
that the companies have signed a global
distribution agreement.
AOS is a leading developer of advanced
semiconductor solutions. AOS products
stocked by Digi-Key are featured in its print
and online catalogs and are available for
purchase directly from Digi-Key. This new
distribution agreement will enable Digi-Key to
fulfill both the design and production quantity
needs of its very diverse customer base.
“We are very excited to expand our
semiconductor portfolio with products from
Alpha & Omega Semiconductor,” said Mark
Larson, Digi-Key president and COO. “AOS’
commitment to excellence in design, manufacturing
reliability, and responsiveness to
its customers makes this company a good
match for Digi-Key, and we are certain that
AOS products will be of consequential interest
and appeal to our customers.”
“AOS and Digi-Key complement each
other in its business philosophy of bringing
Vicor Strengthens European Team
Hannes Schachenmayer Catalin Tachiciu
Vicor is investing in its European sales organisation
and announces the appointment of
Catalin Tachiciu as Regional Sales Manager
SolFocus and ISFOC today announced
the completion of SolFocus’ concentrator PV
(CPV) installation in Spain at the Institute of
Concentration Photovoltaic Systems (ISFOC)
Germany, Switzerland and Denmark and
Hannes Schachenmayr to Regional Sales
Manager Eastern Europe.
3MW municipal power production facility.
SolFocus is the first of three companies to
complete its contract with ISFOC in the first
phase of the project. SolFocus has installed
two distinct CPV power plants: 200kW at
Puertollano and 300kW at Almoguera. The
ISFOC facility has performed initial testing and
analysis confirming that in SolFocus’ first commercial
deployment of its flagship product, the
SF-1000P CPV panel, each panel is performing
as designed at specified power levels.
The ISFOC project was created both as a
municipal power plant and a proving ground
for CPV technology. The original contract was
awarded to SolFocus in late 2006, shortly
after the creation of ISFOC as a power-pro-
the best value to customers and best service
in the industry. With Digi-Key’s global
presence and top-rated online commerce,
customers will be able to access AOS’ wide
range of pr oducts in a more efficient manner,”
said Jonus Chen, vice president of
worldwide sales for AOS. “We look forward
to a successful partnership with Digi-Key.”
www.digikey.com
www.aosmd.com
Hannes Schachenmayer has created a
strong distributor network and successfully
developed the customer base in these markets
for Vicor over the past 14 years. He has
over 20 years’ experience in the power supply
business and will now focus his expertise on
building the Eastern European market for
Vicor, which is an important and growing part
of Vicor’s international business.
Catalin Tachiciu, 45, who joins Vicor from
Rohm Semiconductor, brings extensive experience
with him. He graduated from Munich
University with a degree in electronics and
telecommunications and started his professional
career in the semiconductor industry
with Analog Devices and brings a strong
sales and marketing focus in established and
emerging markets.
“We are excited about the addition of
Catalin to the Vicor Team and it confirms
Vicor’s ongoing commitment to developing
the European market, especially Germany.
This appointment will now allow Hannes to
focus on our fast growing Eastern European
territories”, says Andy Gales, Vice President
of International Sales at Vicor.
www.vicoreurope.com
SolFocus Completes CPV Installation at ISFOC’s 3MW
Solar Power Plant
ducing testing facility for high-efficiency CPV
technology. ISFOC sought the most promising
CPV technologies approaching the electrical
generation market, and selected SolFocus in
advance of commercial production. SolFocus
now enters the industrial, commercial, and
utility markets having fine-tuned its design
and technology development to emphasize
reliability and overall system performance at
the ISFOC installation. This month, the California
Energy Commission (CEC) approved
the SF-1000P CPV panel as the very first
CPV product listed for commercial deployment
in the state of California.
www.solfocus.com
Power Systems Design October 2008

INDUSTRY NEWS
General Manager Boosts Management Team at Gresham
Gresham Power Electronics, the Salisbury,
UK based MIL and commercial power solutions
specialist, announces the appointment
of Roger Diment to the position of General
Manager. Roger comes to Gresham form
Rolls Royce where he held a number of technical,
commercial and logistics roles.
Roger’s main focus will be to add further
expertise to Gresham’s considerable global
naval defence sales and to develop new
markets in merchant marine power sys-
tems. He will also assist with direct and distribution
sales of Gresham’s high power density
commercial OEM power supplies.
Gresham Power is part of the power
conversion empire formed of Telkoor Power
Supplies Ltd in Israel, a major supplier of MIL
and custom commercial power solutions and
Digital Power, the San Francisco based market
leader in low profile, high power density
OEM power supplies. This combination of
global design and manufacturing expertise
and very wide market experience offers a
unique source of off the shelf and custom
power conversion products with worldwide
customer support.
Roger has had a long career of working
in “blue-chip” global solution suppliers and
has worked in Europe and the Middle East
providing technical and logistical services.
He has had considerable experience of
marine electrical system which will be a
major asset for his new role with Gresham
Power. He says. “I am convinced that many
of Gresham’s MIL products will provide
value for money solutions for the merchant
marine market and I will be developing sales
channels to develop this business. I am also
looking forward to being involved in our commercial
product sales and will be providing
support to Telkoor’s direct sales in Europe.”
Gresham Power provides static frequency
converters, DC UPS, distributed power
systems and DC:AC inverters for Naval defence
systems and OEM power supplies and
compactPCI products for telecoms, medical,
industrial and commercial applications.
www.greshampower.com
High-Performance Two-Wheel Inverted Pendulum Robot
via R&D Cooperation
STMicroelectronics and the Waseda
University Humanoid Robotics Institute (HRI)
have announced the development of a high-
performance two-wheel inverted
pendulum robot, called WV-1
(Waseda wheeled Vehicle-
No.1), which is the first result
of an ongoing cooperation for
the research and development
of technology and solutions for
innovative humanoid robots and
medical-care robot systems.
ST and HRI are cooperating
to use leading-edge semiconductor
know-how to promote
the speedier development of
innovative ‘humanoids’ and
medical-care robotic systems,
involving researchers and development
engineers from both
ST and HRI. ST will become
a supplier to HRI for semiconductor
products, while also
furnishing HRI with the leadingedge
semiconductor prototypes
on a cost-free basis, making it
possible for HRI to conduct advanced
evaluations of possible
humanoid and medical-care
robotic applications. In addition,
future cooperation between
ST and HRI is expected to
include the establishment of
an ST-sponsored scholarship system for HRI
students.
The WV-1 is a two-wheeled robot on which
a pole with weights is installed in an inverted
fashion on a pedestal. A feedback system,
controlled with the STM32, ST’s ARM ®
Cortex-M3 based 32-bit MCU and the
LIS344ALH 3-axis digital acceleration sensor,
allows the robot to move while maintaining
its balance. The MCU rapidly computes the
angle of robot body incline, angular velocity
and other sensor data, enabling the motor to
constantly generate optimum torque, which
allows the robot to continue moving smoothly
without tipping over. Potential applications for
this inverted pendulum robot control technology
include postural control functions for
humanoids and other devices, realizing new
means of mobility.
HRI received a grant from “the project
for reinforcement of development technologies
for robotics” from The Robotics Industry
Development Council. The grant was used
for the development of the WV-1. Additionally,
HRI is now working on plans to commercialize
the robot.
www.st.com
www.humanoid.waseda.ac.jp
Power Systems Design October 2008
Electronica - Hall B6, Stand 368

10
INDUSTRY NEWS
Critical
MADE IN USA
LONG-LIFE
HIGH RELIABILITY
1205 McConville Road
Lynchburg, Virginia 24502 USA
tel. 434.239.6941
fax. 434.239.4730
www.paktron.com
PK13988
www.paktron.com
MULTILAYER POLYMER (MLP)
CAPACITORS
Ultra low ESR and ESL
High Ripple Current Handling
Stable Under AC & DC Voltage
Military/Telecom/Datacom
99.999% (5x9) Up Time
Low Profile For Surface Mount
Robust Mechanical and Electrical
Design
50 to 500 Volts
APPLICATIONS
48 Volt Telecom/Datacom
HEV - Hybrid Electric Vehicle
Boost Converters
High Voltage Bus from 48 to 440+
Volts
PFC Front Ends & SMPS Off-Line
RFI/EMI Suppression
DISTRIBUTED IN EUROPE BY:
FUTURE ELECTRONICS
FUTURE HOUSE, THE GLANTY
EGHAM, SURREY
TW20 9AH UK
TEL: +44 1784 275000
FAX: +44 1784 275600
electronica 2008:
FUTURE ELECTRONICS -
AREA A3, BOOTH 441
LTi REEnergy
Selects Maxwell
Technology BOOSTCAP ®
Ultracapacitors for Backup
Power in Wind Turbines
Maxwell Technologies Inc. announced today that LTi REEnergy
GmbH (LTi), one of the world’s leading producers of electro-mechanical
wind turbine blade pitch control systems, has selected
Maxwell’s BOOSTCAP ® Ultracapacitors to supply backup power for
LTi’s PitchMaster ® blade pitch control system.
Blade pitch control systems enhance the consistency of wind turbines’
electrical energy output and ensure that rotor speed remains
within a safe operating range by constantly adjusting turbine blades
to compensate for changes in wind velocity. Ultracapacitors supply
backup power for orderly system shutdown in the event of a main
system power failure.
David Schramm, Maxwell’s president and chief executive officer,
said that LTi’s PitchMaster ® system incorporates multi-cell BOOST-
CAP ultracapacitor modules based on Maxwell’s BCAP0350 “D cell”
product.
“LTi supplies blade pitch control systems to a number of major
wind turbine manufacturers around the world, and already sold more
than one thousand PitchMaster ® systems, so this new supply agreement
represents a significant expansion of Maxwell’s penetration of
the rapidly growing wind energy industry,” Schramm said. “We are
pleased to be aligned with another leading player in the dynamic
renewable energy marketplace.”
Matthias Vehring, LTi’s Managing Director, said that ultracapacitors
were chosen over batteries for backup power because of their
longer operating life, lower maintenance requirements and ability to
operate more reliably in harsh climates.
“Wind turbine operators need systems that perform reliably for
many years in all weather conditions with minimal maintenance,”
Vehring said. “BOOSTCAP products have demonstrated their durability
and reliability at temperatures ranging from -40 to +65 o C, which
enables our pitch control systems to better meet our customers’
expectations.”
Industry sources report that nearly 20,000MW of new wind generator
capacity was installed in 2007, bringing the total worldwide installed
base to approximately 94,000MW. From 2003 through 2007,
the industry maintained an annual growth rate of more than 20%,
and it is projected to continue to meet or exceed that rate through
2012.
www.maxwell.com
www.reenergy.lt-i.com
Power Systems Design October 2008
Pick the best coupled inductor for
your SEPIC converter in less time
than it takes to read this ad.
With over 135 coupled
inductors to pick from,
choosing the right one
might seem difficult.
But our new on-line
tools make it incredibly
accurate and easy.
Enter data about your SEPIC converter and
you’ll get detailed specifications on all the
(and have free samples on your desk tomorrow)
RoHS
COMPLIANT
coupled inductors that meet your needs. A few
more clicks gives you a detailed analysis of core
and winding losses. The whole process can literally
take less than a minute.
When you’re done, be sure to ask
for free evaluation samples. We’ll
ship them that same day.
Start your coupled inductor
search at coilcraft.com/sepic
®
New! LPD3015 and LPD4012 miniature
coupled inductors. Perfect for LED
drivers in portable equipment.
21 Napier Place, Wardpark North, Cumbernauld UK G68 0LL
+44/1236/730595 Fax +44/1236/730627

12
INDUSTRY NEWS
Microsemi Appoints Bel Lazar Senior VP of Operations
Microsemi Corporation has announced
the appointment of Bel Lazar as Senior Vice
President of Operations, reporting to Ralph
Brandi, Executive Vice President and Chief
Operating Officer.
Lazar comes to Microsemi from International
Rectifier, where he was Vice President of
the Aerospace & Defense Business Unit, having
responsibilities for operations in Leominster,
Massachusetts, Santa Clara, California,
and Denmark.
“We are excited to welcome Bel to Microsemi,”
said Ralph Brandi. “Microsemi has
entered exciting new territory in the last year,
introducing a number of RadHard parts for
military and aerospace applications, with
more products on the roadmap for release
in the near future. These are some of the
most profitable high-reliability markets and
TTI Signs Pan-European Franchise Deal with C&K Components
TTI, Inc. a leading passive, connector and
electro-mechanical specialist distributor in the
electronics industry, has signed a distribution
agreement with C&K Components, a recognized
leader in the design and manufacture
of switches, smart card interconnect devices,
and high reliability connectors. C&K is known
throughout the world as one of the most relied
upon switch manufacturers and offers the
broadest portfolio of switch products as well
as specialty connectors.
Comments John Sandy, TTI’s European Director
Supplier Marketing Connectors: “There
is no doubt that C&K is one of the world’s
leading switch brands. I’m confident that our
current switch portfolio allows us to address
any and all market requirements.”
Adds Henk Raaijmakers: C&K Components’
Distribution Manager Switches for Cen-
Lineage Power Corporation has announced
that Chris Meaney has been appointed global
vice president of OEM sales. Meaney will be
responsible for driving the global sales strategy
for the OEM (original equipment manufacturers)
market.
Most recently, Meaney served as vice
president of sales at IntraLinks, a leading
provider of virtual data room workspaces and
other online workflow management solutions.
Primarily responsible for the regional
direct sales team, Meaney played a key role
in generating a $14 million revenue stream.
Before IntraLinks, Meaney held multiple sales
positions for Siemens Enterprise Communications,
where he managed regional and global
accounts, such as Coca-Cola, IBM, UPS and
Ford Motor Company. Meaney also served
as multi-services regional manager at Cisco
Systems.
represent an entirely new growth opportunity
for the company. Bel's deep understanding of
these technologies and applications makes
him an integral part of the team and a key
component of our next generation growth
strategy.”
Lazar, who has a Juris Doctor degree
from Southwestern University School of
Law, earned a Master of Science degree in
Computer Engineering from the University of
Southern California in 1986 and a Bachelor
of Science degree in Electrical Engineering
from California State University, Northridge, in
1984.
tral & Nordic Europe: “TTI is very focused on
our sector and has a track record of targeting
new business rather than just trying to take
market share. Customers will have access to
a wide range of our products stocked in depth
by TTI.”
Lineage Power Appoints Global VP of OEM Sales
www.microsemi.com
www.ck-components.com
Meaney earned his bachelor’s degree in
electrical engineering from the University of
Vermont. He will be based in Atlanta.
www.lineagepower.com
Power Events
electronicAsia 2008,
October 13-16, Hong Kong, China,
www.electronicasia.net
electronica 2008,
November 11-14, Munich, Germany,
www.electronica.de
SPS/IPC/Drives 2008,
November 25-27, Nürnberg, Germany,
www.mesago.de/en/SPS/main.htm
Power Systems Design October 2008

14
Energy-Efficient Chokes
for Transportation
SMP Sintermetalle Prometheus
GmbH & Co KG, manufacturers
of inductive components and
magnetically soft materials, cores and
mouldings is based in Graben-Neudorf
near Karlsruhe, Germany and has introduced
a range of chokes designed
specifically for use with inverters. The
special feature of these units is their
ingress protection class of IP66, which
makes them suitable for use in tough
environments as found in rail transportation,
to restrict incoming current on the
line side.
Because of the high degree of protection,
these chokes can be fitted outside
the inverters, so the heat generated by
the choke is not discharged inside the
inverter. This results in a lower internal
inverter temperature, which removes
the need for cooling fans, saving both
energy and installation space. Placing
the choke outside the inverter has
the further advantage of reducing the
inverter’s overall dimensions, which
further cuts space and energy demand.
For the choke itself, external mounting
has the benefit of allowing it to be designed
for lower ambient temperatures.
While inverters, for example in railway
applications, can have an internal
temperature of 70 to 80°C, the outside
temperature to which underfloor-mounted
electronics are exposed is unlikely to
exceed about 40°C. SMP has developed
chokes for external mounting even
for use on offshore oil platforms. Their
special protective paint coating protects
these components from direct sunlight,
sea water, rain and corrosive gasses.
To simplify mounting outside the
inverters, SMP provides the chokes with
special mounting fixtures. The choke
and the mounting plate are fitted on the
device’s outside and the connecting
cables pass through a sealed opening.
SMP choke for railway applications.
To meet demanding requirements in
power electronics, SMP has developed
high-performance chokes and filters.
These inductive components offer a high
energy storage capacity at low volume,
reduced losses, good EMC characteristics
and a cost-conscious design.
Depending on their application, they are
constructed either as single-conductor
chokes for high-current applications,
individual chokes, choke modules or LC
filters.
For wider applications in power electronics,
power generation, instrumentation
and control, SMP supplies chokes
and filters for frequencies up to 200kHz
and current ratings up to 1000 amperes,
with component sizes ranging from 36
to 300mm diameter and weights from
50g to 130kg. The components can
be used in a temperature range up to
180°C. They are easy to fit and, with
numerous mounting options, can be
mounted according to the available
space. To allow for a wide range of requirements,
components can be made
to all common standards, including protection
type IP20 and IP65. All products
are RoHS- and WEEE-conformant and
the materials used are UL-listed.
www.smp.de
Power Systems Design October 2008

16
Optimized Power Processing
and Energy Efficiency
By Oleg Khaykin, President and Chief Executive Officer, International Rectifier
Power management plays a key
role in enabling energy efficiency
advancements in the vast number
of products that we depend on as we
go about our daily lives. However, it’s a
term that has been misused by companies
looking to gain traction with Internet
keywords optimized for Google and Yahoo
searches as they seek to exploit the
growing buzz around saving the world’s
dwindling energy reserves.
So what exactly is power management?
It is power sequencing or communication
and in some cases, regulation,
and it is the first link in the power
processing chain. To achieve real power
savings in a system, the integration of
multiple components is required that
encompasses both the power management
and the power conversion stages.
When you combine load-centric
power conversion with system-centric
power management, you have a better
chance of improving efficiency within an
application. This is the essence of optimized
power processing. The result is
longer battery life, fewer kilowatt hours
when your notebook is plugged into the
wall, or more functionality from your cell
phone because each component is being
managed more efficiently.
The opportunity to save energy using
this approach is enormous. Take the data
center as an example. Information about
the power load needs to be combined
with information going on at the board level,
inside the server rack and in the entire
room to maximize efficiency. This doesn’t
happen when components aren’t integrated
effectively, and with data centers now
consuming as much as 3 percent of all
power, there is growing pressure to curb
their energy consumption.
more than 80 percent of these motors
are wastefully controlled electro-mechanically.
Designs are moving towards
variable-speed permanent magnet motors
that are smaller, lighter and lower
cost, and as long as you have a good
control technique, permanent magnet
inverterized motor control can achieve
95 percent efficiency by co-designing
the power train and the driver, and an
algorithm to control them.
This all points back to power processing
and engineers are forced into making
tradeoffs between higher efficiency and
maximum cost-effectiveness, or to deliver
efficiency and density at a higher price.
These issues can be solved by providing
complete solutions from switch to
drive scheme to power management.
Matching and optimizing digital and
analog control with power stage components,
and integrating them with new
packaging technologies will continue
to increase the power density with less
wasted energy while simultaneously reducing
system size, complexity and cost.
others, new materials are needed. As a
market leader, it is natural for IR to pursue
opportunities for advancing power
conversion technology by leveraging the
company’s 60-year heritage in power
conversion expertise in AC-DC converters,
DC-DC converters, motor drives
and lighting systems.
The advent of GaN on Silicon epitaxial
technology together with the ability to
develop a process that is compatible
with IR’s silicon manufacturing facilities
allows IR to offer customers commercially
viable products using GaN-based
power devices.
These devices can provide customers
with improvements in key applicationspecific
figures of merit (FOM) of up to a
factor of ten compared to state-of-theart
silicon-based technology platforms,
dramatically increasing performance
and cutting energy consumption in end
applications in market segments including
computing and communications,
automotive and appliances.
GaN-based power devices will eventually
be used in most of the same applications
as current silicon-based power
devices, as well as new applications currently
not possible with silicon devices.
These applications will evolve over the
coming decades, as GaN-based power
devices replace silicon based power
devices as the technology platform of
choice. Early adopters will be market
segments and applications that take full
advantage of the revolutionary capability
of transforming the value realization of
the key features of power density, power
conversion efficiency and cost.
All of these innovations are geared
toward achieving more functionality using
significantly less power—and a sharp
reduction in the number of buzzwords
needed to accomplish it.
Electric motors present another
golden opportunity. Consuming over In some cases, new techniques are
50 percent of the world’s electricity, required for building components and in
www.irf.com
Power Systems Design October 2008
© 2008, National Semiconductor Corporation. National Semiconductor, , and PowerWise are registered trademarks. All rights reserved.
N o v e m b e r 1 1 – 1 4
See us at our booth A4.506
national.com/LED
High Brightness. Low Power.
Energy-Effi cient LED Lighting Solutions
National Semiconductor’s PowerWise ® lighting solutions have the best power-toperformance
ratios, offer a wide variety of features including dimming and thermal
management to extend the life of LEDs, minimize external component count, and
enable robust designs.
Automotive Lighting
Architectural Lighting
National’s easy-to-use
constant-current LED drivers
drive up to 20 LEDs in series,
provide greater than 90%
effi ciency, and offer accurate
current control, dimming and
thermal performance for indoor
and outdoor architectural
lighting applications.
Architectural Lighting
Outdoor Lighting
National’s ultra high-efficiency
and high-reliability LED
drivers with wide operating
voltage range help customers
minimize total system cost
by driving up to 20 LEDs in
one string. At the same time,
thermal management ICs
supply accurate temperature
information to avoid LED
overheating.
Outdoor Lighting
Automotive Lighting
Robust protection and fault
fl ag at over-current, overvoltage
and over-temperature
make National’s LED drivers
ideal solutions for highreliability
automotive exterior,
interior and back lighting
systems.

18
Portable Power- Management
Market Throws the Switch
Revenue expected to grow to $7.8 billion by 2012
Booming sales of portable devices
capable of accessing the Internet
have spurred fast growth in
demand for power-management semiconductors
for this application, according
to iSuppli Corp.
Global portable power management
semiconductor revenue will expand to
$7.8 billion by 2012, rising at a Compound
Annual Growth Rate (CAGR) of
10.6 percent from $4.7 billion in 2007.
Figure 1 presents iSuppli's revenue
forecast for power-management
semiconductors for the period of 2007
through 2012.
Notebook PCs and 3G mobile handsets
will be the biggest markets for
power-management semiconductors,
registering CAGRs of 18.7 percent and
26.8 percent respectively from 2007 to
2012.
Sales of portable power-management
semiconductors are being driven by
the need for more efficient electrical
consumption by power-hungry microprocessors,
memories and audio and
video application ICs. This requirement
is only increasing as today's users are
demanding greater
mobility, more content,
enhanced functionality,
longer battery life
and increased power
for components.
Getting efficient
As mobile devices'
functionality has
increased and their
energy-usage requirements
have become
more stringent,
designers and OEMs
By Marijana Vukicevic, iSuppli Corp.
have embraced power-management
semiconductor integration as a means
to improve efficiency.
Rising integration more than likely will
limit sales growth for more traditional,
discrete solutions. For suppliers, future
growth will hinge on offering more
integrated solutions, such as highly integrated
switching regulators or Power
Management Units (PMUs), iSuppli
believes.
Furthermore, the phase out of discrete
low-power MOSFETS in notebook
PCs will be delayed with upcoming
Intel Corp. microprocessors because
the increased power demands from the
company's new quad-core chips.
Powering up
Discrete solutions will face particular
challenges competing against more
integrated alternatives in the mobile
handset market. In order to survive,
discrete suppliers must shift their efforts
to the integrated solutions, iSuppli
believes.
Texas Instruments Inc. has done this
by utilizing its expertise in both the
wireless and power-management markets
to benefit in the integrated market.
Qualcomm has done the same thing,
although not by using organic means.
Integrated solutions require major
investments in development and the
majority of traditional discrete solution
providers will face difficulties when trying
to expand their business in the wireless
market.
As users demand more content from
their portable devices
and big entertainment
companies shift their
business models to
take advantage of
such products, power
management will only
play an increasingly
crucial role in enabling
these applications
to be brought to the
masses.
www.isuppli.com
Power Systems Design October 2008

20
DESIGN TIPS
Power Supply Control
Design Tools – Part VI
Modeling Power Supplies with
Current-Mode Control
The buck-boost converter (or flyback
converter in its isolated version) is the
most popular converter for generating
low power with multiple output voltage
levels. The converter can be run in
many different modes – discontinuous
conduction mode (DCM), continuous
conduction mode(CCM), quasi-resonant
mode (DCM with switching at the bottom
of the DCM ring wave), and various
options of fixed or variable frequency.
The choice of operation depends on
the power level, the application, and the
control chip used.
Regardless of the mode of operation
of the power stage, current-mode
control is almost always used, as
shown in Figure 1. Many designers
strive to always keep their converter
in DCM in order to avoid some of the
complexities of control. This is not
necessary if current mode control is
used, and keeping the converter DCM
under every condition of line and load
can create large peak stresses in the
semiconductors.
While it is an intuitive control scheme,
the proper analysis of current mode
control is complex. The dynamic analysis
of current mode involves advanced
techniques, including discrete-time and
sampled-data modeling. This is essential
Buck-Boost Converter with
Current-Mode Control
In this article, Dr. Ridley presents a summary of current-mode control for the buck-boost converter.
A free piece of analysis software, the final one in a series of six, is provided to readers of this column to
aid with the analysis of their current-mode buck-boost converters.
By Dr. Ray Ridley, Ridley Engineering
to arrive at a model which explains all of
the phenomena seen with your converter,
and which accurately predicts the
measured control-to-output response
and loop gain of the current-mode converter.
The full analysis of current-mode
control can be downloaded from www.
ridleyengineering.com.
Figure 2 shows a plot of the control
characteristics of the buck-boost converter
in both DCM and CCM. Notice
that these characteristics do not change
very much at low frequencies, making
control optimization straightforward for
converters that must operate in both
regions.
There are several important points
to learn from the full analysis of the
current-mode boost converter:
1. The power stage has a dominantpole
response at low frequencies,
determined mainly by the time constant
of the output capacitor and load resistor
values. This dominant pole response
does not vary significantly as the converter
moves from DCM to CCM operation,
as can be seen in Figure 2.
2. In CCM, the power stage has an
additional pair of complex poles at half
the switching frequency which, under
certain conditions, will create instability
in the current feedback loop. The
damping of these complex poles is
controlled by the addition of a compensating
ramp.
3. The resulting transfer function of the
CCM power stage is third-order, even
though there are only two state variables
in the converter. (This apparent anomaly,
for control theorists, is caused by the
fact that the switching power converter
is a nonlinear, time-varying system.)
4. The second-order double poles at
half the switching frequency cannot be
ignored, even though they may be well
beyond the predicted loop crossover
frequency.
5. The capacitor ESR zero is unchanged
by the presence of the current
loop feedback.
Power Systems Design October 2008

DESIGN TIPS DESIGN TIPS
Figure 1: Buck-boost converter with current-mode control. The green components show the current feedback; without these,
the control is voltage-mode.
6. Finally, and most importantly, the
current-mode boost converter retains
the exact same RHP zero as the
voltage-mode converter. However, since
the current feedback has eliminated the
double poles of the filter resonance, it
is not difficult to control this RHP zero
effectively.
As explained in reference [1],
current-mode control has many advantages.
These include elimination
of the resonant filter frequency, the
ability to current share with multiple
power stages, simplified compensation
design, and inherent peak current
limiting.
Designing with Current-Mode Control
While the analysis of current-mode
control is quite complex to understand,
the design process is quite simple.
Much simpler, in fact, than voltagemode
control, and this is one of the
reasons that current-mode control is so
popular today.
The switch current of the circuit of
Figure 1 is sensed and compared to a
voltage reference to set the duty cycle
of the converter. A sawtooth ramp is
added to the signal to stabilize the current
loop. For the buck-boost converter,
it is recommended to use a stabilizing
ramp at greater than 40% duty cycle in
Figure 2: Response of the buck-boost converter with current-mode control in both
CCM and DCM operating modes. At lower frequencies, the characteristics do not
significantly change, and this is an important advantage of current-mode control.
CCM operation.
Closing the current loop is straightforward.
A current transformer, or sense
resistor, is used to generate a voltage
signal proportional to the current in the
switch. The only requirement on the
design of this network is that the resulting
signal should not exceed the voltage
headroom available in the PWM comparator.
You do not have to think about
the gain of the current loop, or resulting
transfer functions at all during this phase
of the design.
Once the current sense network is
selected, you must decide whether you
need to add a compensating ramp to
the system. Further details of how to
add the ramp are given in [1]. Addition
of the compensating ramp provides independent
control of the PWM modulator
gain.
Buck-Boost Converter Current-
Mode Software
Software is available for download
that allows you to predict the smallsignal
response of your buck-boost
converter with current-mode control.
After entering your power stage values
and switching frequency, you can
design the current loop parameters of
current gain, and compensating ramp
value. The software will help you choose
the proper values. Once this is done, the
transfer function gain and phase of the
power stage is plotted for you, and the
resulting poles and zeros given.
The software is designed to run under
either Excel 2007 or Excel 2003. Make
sure when you open the software that
the macro features are enabled in order
to use the program properly. Please go
to www.ridleyengineering.com to download
the software.
Summary
If you work with a buck-boost converter,
it is advisable to use currentmode
control, even if you operate the
converter in DCM. While the analysis is
complex, the software tool made avail-
able with this article will help you design
the current loop properly and show
the transfer functions of the converter.
Remember, however, the results of any
power supply transfer functions should
always be verified by measurement.
Power systems are frequently dependent
on circuit component parasitics
that can be unpredictable, and can also
be impacted by noise and improper
board layout. Experimental verification
[2] is an essential step for a rugged design,
and should never be omitted.
References
1. “A New Small-signal Model for
Current-Mode Control”, Raymond B.
Ridley,1990 PhD dissertation, free download
is available at www.ridleyengineering.com/cmode.htm
2. “Measuring Frequency Response,
Tips and Methods” http://www.ridleyengineering.com/downloads/Spring
2002
feature.pdf
www.ridleyengineering.com
22 Power Systems Design October 2008
www.powersystemsdesign.com
23

24
ON THE ROAD
On the Road
Reported by Cliff Keys, Editor-in-Chief, PSDE
I visited Fairchild’s facility in Portland, Maine, US, and had the opportunity to speak with Guy Moxley,
Fairchild’s Senior Director of Low Voltage Marketing. He took me through the company’s latest
contribution to their drive for industry power efficiency.
Fairchild’s Next Generation DrMOS Delivers 92% Efficiency
Fairchild’s Multi-Chip Modules follow
the traditional definition in that they are
the integration of switching, control and
driver ICs, and passive components
to form a system to achieve the most
optimal solution for a given application
using components that are matched
electrically, thermally and mechanically.
The ever problematic EMI has been
minimized by Fairchild’s engineers by
judicious layout and lead configuration
within the module itself to provide a
complete solution.
TinyBuckTM Multi-Chip Module with Intelstandard
DrMOS driver plus MOSFETs.
With today’s increased focus on efficiency,
several government organizations
are driving energy efficiency initiatives
such as Energy Star and Climate
Savers by Google and Intel who are driving
for significant reduction of electricity
costs in servers by IT departments,
increased focus on smaller form factors
for blade and rack servers and smaller
desktop PCs.
TinyBuckTM is Fairchild’s family
of fully-integrated synchronous buck
converter switching regulator solutions.
These products include a controller IC,
a driver IC, one high-side MOSFET one
low-side MOSFET in a space-¬efficient
MLP package.
DrMOS is an Intel standard that defines
the specifications and functionality
of a FET-plus-Driver multi-chip module.
Fairchild worked extensively with Intel on
the development of this specification and
offers an extensive portfolio of DrMOS
modules in two versions: 8mmX8mm
and 6mmX6mm MLP packages.
Fairchild’s DrMOS, the FDMFxxxx series,
is a complete family of fully optimized,
integrated FET-plus-Driver multi-chip power
stage modules designed for multiple
synchronous buck converter applications.
These multi-chip modules are designed to
achieve the optimal solution using components
that are accurately matched.
Fairchild Semiconductor has recently
introduced its XS DrMOS, the industry’s
first high-performance and spaceefficient
6mm x 6mm DrMOS solution
for synchronous DC-DC buck regulators
for computing, game console and
consumer Point-of-Load (POL) applications.
The FDMF6704 is a FET-Plus-
Driver module that replaces one driver
IC, one high-side MOSFET, two low-side
MOSFETS and one bootstrap Schottky
diode in an ultra-compact package. The
thermally enhanced 6mm x 6mm MLP
package saves 84 percent board space
compared to discrete solutions and 44
percent compared to 8mm x 8mm MLP
packaged DrMOS modules. It delivers
92 percent peak efficiency, enabling
applications to meet stringent energy-efficiency
specifications such as ENERGY
STAR ® , Climate Savers ® and Green
Grid SM .
The XS DrMOS family is
Fairchild’s next-generation fully optimized
ultra-compact integrated MOSFET
plus driver power stage solution for high
current, high frequency synchronous
buck DC-DC applications. With an integrated
approach, the complete switching
power stage is optimized with regards
to driver and MOSFET dynamic performance,
system inductance and R DS(ON).
This greatly reduces the package parasitics
and layout challenges associated
with conventional discrete solutions. The
driver IC incorporates advanced features
such as SMOD. PWM input is Tri-
State compatible. A 5V gate drive and
an improved PCB interface [Low Side
MOSFET exposed pad] ensure higher
performance. This product is compatible
with the new Intel 6mm x 6mm DrMOS
specification.
With an abundance of advanced
features, the FDMF6704 has been
designed and optimized to work with a
wide variety of controllers in the market.
It is compatible with both Tri-State and
Non-Tri-State PWM controllers. To fur-
Power Systems Design October 2008

26
ON THE ROAD
ther ensure compatibility, the FDMF6704
has its PWM threshold levels tailored to
meet a broad range of controllers available
in the market. Fairchild’s advanced
SyncFET technology is integrated
within the module’s low-side MOSFET
further ensuring higher performance.
The FDMF6704 utilizes lead-free (Pbfree)
terminals and has been characterized
for moisture sensitivity in accordance
with the Pb-free reflow requirements
of the joint IPC/JEDEC standard
J-STD-020. All of Fairchild’s products
are designed to meet the requirements
of the European Union’s Directive on the
restriction of the use of certain substances
(RoHS).
electronica: Hall A4 Stand 121
TI Launches Industry-Thinnest 500 mA Converter Solution
www.fairchildsemi.com
At TI’s recent press conference in Freising, Germany, I was able to get the company’s latest in good
news from TI for portable equipment designers from Uwe Mengelkamp, Director DC/DC Converters
(worldwide) for Texas Instruments.
Texas Instruments announced the
industry’s smallest and thinnest 500mA,
step-down DC/DC converter solution
for space-constrained applications. The
new product, TPS62601, gives portable
designers the unique ability to add more
features and functions on a handheld
device. This high-efficiency power
management integrated circuit is the
first 6MHz, 500mA converter to achieve
a 13mm 2 solution size with an ultra-thin
0.6mm total height, vital for competitive
advantage in portable devices.
Leveraging TI’s long standing analog
manufacturing technology, the new
TPS62601 converter achieves up to 89%
power efficiency and only 30µA typical
operating quiescent current – all from
a 0.9mm x 1.3mm chip scale package
roughly the size of a flake of pepper. The
synchronous, switch-mode device’s fixed
frequency of 6 MHz allows the use of
only one 0.47µH inductor with a height of
0.6mm and two low-cost ceramic capacitors,
without compromising performance
and efficiency.
“Portable system designers continue
to desire more features on their devices,
Texas Instruments
Uwe Mengelkamp, Director DC/DC Converters
(worldwide) for TI.
which require smaller, efficient DC/DC
converters to maintain long battery life
and system run-times,” said Uwe Mengelkamp,
Director DC/DC Converters, TI.
“The TPS62601 gives portable designers
access to the smallest, thinnest 500mA
DC/DC solution, which simplifies design
and reduces board space and time-tomarket.”
The TPS62601 can deliver DC voltage
regulation accuracy of +/-1.5%. In addition,
the device’s excellent load transient
response, wide input voltage range of
2.3 V to 5.5V and 1.8V of output allows
it to effectively support single-rail voltage
requirements as designers add new features
and functionality. The TPS62601
supports many applications, such
as memory modules, GPS modules,
wireless micro-modules used in ultrathin
smart phones, digital still cameras,
portable disk drives and media players.
The converter also applies energysaving
techniques to help maximize battery
run-time. For example, the converter
automatically enters a power save mode
during light-load operating conditions via
an automatic pulse frequency modulation
and pulse width modulation switching
feature. In shutdown mode, the
device’s current consumption is reduced
to less than 1µA.
The TPS62601 is available immediately
in volume from TI and its authorized
distributors. The device comes
in a highly reliable, six-pin, wafer chip
scale (0.9mm x 1.3mm) package and
has a suggested resale price of $1.45
each in quantities of 1,000 units. The
TPS62601EVM-327 evaluation module,
application notes and TI’s online Power
Management selection tool are available
through power.ti.com.
In addition to the TPS62601, TI provides
a broad range of power management
battery management solutions for
handheld devices. Examples include
the new 3-MHz bq24150, switch-mode
battery charger integrated circuit, the
system-side bq27500 battery fuel gauges,
and TI’s DC/DC converters that support
RF power amplifiers and core supply voltages.
Complete system block diagrams
with analog and digital solutions for
OMAP 3 processor-based applications
can be found at: www.ti.com/omap3.
electronica: Hall A4 Stand 414
Bluetooth and Wi-Fi modules or other www.ti.com
Power Systems Design October 2008
Sensorless Field-Oriented
Motor Control
Improve your current motor control
design with FOC
• Gain Higher Energy Efficiency
• Eliminate Costly Sensors
Price is no longer prohibitive for
field-oriented control with the industryʼs
largest portfolio of motor control Digital Signal
Controllers.
GET STARTED NOW...
• Reduce Noise
• Improve Dynamic Response
Microchip also offers a variety of low-cost
development tools, free software libraries and
other design resources for field-oriented control
of PMSM and ACIM motors.
• Download FREE MOTOR CONTROL SOFTWARE LIBRARIES – including FOC Sensorless
PMSM or ACIM, as well as on-chip power-factor correction algorithms
• Request FREE SAMPLES of dsPIC ® Digital Signal Controller optimized for motor control
• See the Microchip website for the current MOTOR CONTROL PROMOTIONS AND DISCOUNTS!
• FULL TECHNICAL SUPPORT 24/7 - including webinars, application notes & technical training classes
Visit www.microchip.com/DSCMotor today
www.microchip.com
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
of their respective owners. © 2008 Microchip Technology Inc. All rights reserved. ME190Eng/03.08

ON THE ROAD ON THE ROAD
Sharp Microelectronics Europe
I had the great pleasure and opportunity to attend the Sharp Innovation forum held in the beautiful south
of Germany recently. Within the assembled press, I was very interested to see the presentations of the
company’s technology experts where I captured much information for future publication. Maximilian Huber,
President Sharp Microelectronics Europe gave us all an update of the Sharp of today going forward.
Although the status of Sharp in the display arena is well known and accepted, Maximilian spelled out the
major goals set for the company.
Innovation Forum Overview
Sharp now invests about 5.7% of its
annual net sales in Research and Development
with approximately 1.22 Billion
Euros invested in FY 2007.
Worldwide 8,200 researchers are
working to drive Sharp’s appropriately
called “one-of-a-kind” innovation in technology
areas of LCD, Opto electronics
and IC components.
Sharp’s global R&D network is built
on five bases in four countries to ensure
close proximity to relevant centers of
excellence for the company’s wide ranging
technology fields. Close contact with
localized universities ensure efficient
technology transfer to keep Sharp at the
cutting edge of its business areas.
Large-size LCDs
At the forum, Sharp announced the
world’s first 108 inch monitor. This
hugely impressive display will be on
show at electronica in Munich, Germany.
The company’s G8 and G10 factory is
optimized for increased efficiency for AV
and e-signage display manufacturing.
LEDs for lighting
Sharp is Increasing LED efficiency for
new display backlighting and lighting
systems with more natural colors, higher
robustness, less power consumption and
flexible utilization.
Green Products
Throughout the world, there are approximately
1.2 Billion CRT TVs in operation.
If they were all replaced by LCD TV
with Sharp’s new technology, the reduction
of energy consumption would stand
at around 100 Billion kWh per year. This
is equivalent to the annual capacity of 14
power plants or 34 Million tons of CO 2.
Maximilian Huber, President, Sharp
Microelectronics Europe.
General targets for Sharp’s green factories
of the future include the reduction
of CO 2-emissions per output unit (2%
reduction per year) together with the
aggressive goal of “Zero Waste” which
means that only a meagre 0,5% of waste
is committed to landfill.
A good example of this is the LCD-
Factory in Kameyama where a co-generation
system and solar cells produce
over 30% of the power needed. CO 2emissions
are reduced by 40% and
100% of water consumed is re-used in
the production process.
Display market overview
TV: Sharp is focused on significantly
increasing its market share of LCD TV
from today’s 37% to 68% by 2011.
e-signage: the company’s goal is for
an 11-fold increase in volume of LCD
e-signage displays in EMEA markets
from 336k units in 2007 to 3.8 Million
units in 2011.
PC Market: LCDs currently account
for 90% of all PC monitor sales.
Automotive: Sharp predicts the market
for navigation systems (fixed + PND)
will double from 45 Million units in 2007
to 90 Million units in 2010.
Portable Applications: A steady
volume increase on high level (4 Billion
units in 2007), with a technology shift
towards active matrix displays.
Sharp predicts that overall, LCDs will
continue to be a growth driver for the
foreseeable future.
LCD: One Technology does it all
This is a mature technology with large
potential for further innovation. The reliable
technology delivers ever more brilliant
images for consumers and enables
production of displays flexible in size:
from 1.5 inch to 108 inch and beyond.
Caption: Innovative TFT displays are key
components for situation-relevant driver
information and in-car infotainment systems
as they allow more flexibility and new
functions in the design of modern vehicle
interior and safety concepts. Depending on
the type of use within the vehicle – whether
as an information cluster display, a central
navigation and information display or as
a screen rear-seat entertainment - Sharp
offers TFT LCDs with wide ranging technical
configurations optimized for the respective
application.
LCDs give great flexibility to designers
with many available technologies to optimize
development for different applications,
examples of which are found in:
• TV
• e-signage
• Factory automation
• Automotive applications
• Industrial handhelds
• Mobile communication
Business development in Europe
Maximilian was clear that it is now
time to change. With progressive market
conditions, there are challenges
and therefore opportunities. Emerging
business areas that Sharp is targeting
include:
e-signage with digital, centrally operated
public information
LED technology where energy saving,
natural colour rendering of light
sources for lighting and backlight systems
are paramount.
Automotive displays where multifunctional
interface is replacing the
traditional analog pointer instruments
Industrial Handhelds for decentralized
process automation, for example, in
the logistics and medical services areas.
Summary
The display market will be one of the
most important growth drivers for the fu-
Linear Technology
ture in many market segments. Sharp has
been and will continue to be a leading
player in this market. Maintaining a highly
successful position in this market requires
a strong focus on leading edge technology
in application oriented markets.
Finally, the increasing awareness in
the environmental and social responsibility
give Sharp a competitive advantage
due to its exemplary record in the
approach taken in the development and
manufacturing of its products.
electronica: Hall A3 Stand 207, 225
Hall A4 Stand 578
www.sharpsme.com
At its press conference in Munich, Germany recently, Linear Technology announced the LTC6802, a
highly integrated multicell battery monitoring IC capable of measuring up to 12 individual battery cells.
HV Battery Stack Monitor for HEVs & Battery Backup Systems
The proprietary design of this device
allows multiple LTC6802s to be stacked
in series without optocouplers or isolators,
for precision voltage monitoring
of every cell in long strings of seriesconnected
batteries. Long battery
strings enable high power, rechargeable
applications, such as electric and hybrid
electric vehicles, scooters, motorcycles,
golf carts, wheelchairs, boats, forklifts,
robotics, portable medical equipment,
and uninterruptible power supply (UPS)
systems.
With superior energy density, Lithium-
Ion batteries are poised to be the power
source of choice for these applications.
However, designing a large, highly
Precision, High Voltage Multicell Battery
Stack Monitor.
Erik Soule, VP & General Manager, Signal
Conditioning Products, Linear Technology.
reliable and long-lasting Li-Ion battery
stack is a very complex problem. Li-
Ion cells are sensitive to overcharging
or over-discharging, requiring that each
cell in a stack is carefully managed. The
LTC6802 makes this possible with quick
and accurate measurements of all cell
voltages, even in the presence of stack
voltages over 1000V.
The maximum total measurement error
is guaranteed at less than 0.25% from
-40°C to 85°C and all cell voltages in a
battery stack can be measured within
13ms. Each cell is monitored for undervoltage
and overvoltage conditions,
and an associated MOSFET switch
is available to discharge overcharged
cells. Each LTC6802 communicates via
a 1MHz serial interface, and includes
temperature sensor inputs, GPIO lines
and a precision voltage reference.
The LTC6802 was designed for the
environmental and reliability challenges
of automotive and industrial applications.
It is fully specified for operation from -40
°C to 85°C and offers diagnostics and
fault detection. The LTC6802 is a small
8mm x 12mm surface mount device. The
combined robustness, exceptional precision
and tiny package directly address
the critical requirements of emerging and
advanced battery technologies.
“The LTC6802 provides a precision
analog interface for high performance
battery stacks,” said Erik Soule, Vice
President & General Manager of Linear
Technology’s Signal Conditioning Products.
“By handling the data acquisition
28 Power Systems Design October 2008
www.powersystemsdesign.com
29

30
ON THE ROAD
task, the LTC6802 enables designers to
implement state-of-the-art battery management
techniques.”
Priced at $9.95 each in 1,000-piece
Vicor/Picor
At a recent press conference, Picor, a subsidiary of Vicor Corporation, announced the Cool-ORing
family of full-function Active ORing solutions and discrete Active ORing controllers. These products
address the redundancy requirements in today’s high-availability systems such as servers, high-end
computing and telecom and communications infrastructure systems.
Picor’s Cool-ORingTM family targets redundant power
architectures in high-availability systems
The Cool-ORing PI2121/ PI2123/
PI2125 are complete full-function Active
ORing solutions with integrated highspeed
ORing MOSFET controllers and
very low on-state resistance MOSFETs.
They address a variety of redundant bus
applications, providing very low power
dissipation while achieving very fast dynamic
response, typically within 160ns,
to system level power source fault conditions.
The PI2121 is an 8V, 24A solution
suitable for ≤5Vbus applications, the
PI2123 is a 15V, 15A solution suitable for
≤9.6Vbus applications and the PI2125 is
a 30V, 12A solution suitable for 12Vbus
applications.
The PI2121/ PI2123/ PI2125 solutions
are offered in extremely small, high density,
thermally enhanced 5mm x 7mm
land grid array packages, maintaining
full current ratings over a wide range of
operating temperature. The high level
of density is enabled by integrating a
very low on-state resistance MOSFET
into each product. The typical on-state
resistances are 1.5mOhm, 3mOhm and
5.5mOhm respectively for the PI2121,
PI2123 & PI2125. Each product can also
be paralleled to address higher current
requirements through a master/ slave
feature, enabling an extremely scalable
solution for a wide range of Active ORing
requirements. The PI2121/ PI2123/
PI2125 detect normal forward, excessive
forward, light load, and reverse current
flow through their internal MOSFETs,
and report fault conditions via an active
low fault flag output. A temperature
sensing function indicates a fault if the
maximum junction temperature exceeds
quantities, samples, demonstration
boards and the data sheet are now available
at www.linear.com. The product will
be available in production quantities in
160°C. The under-voltage and overvoltage
thresholds are programmable via
external resistor dividers.
The PI2001 is a discrete high-speed
Active ORing controller with similar
functionality and feature set, for use with
industry standard single or paralleled
MOSFETs.
The PI2003 controller is specifically
optimized for use in -48V redundant
power architectures, and is suitable for
systems requiring operation during input
voltage transients up to 100V for 100ms.
The low quiescent current of the PI2003
enables simple low-loss biasing directly
from the -48V rail.
The Cool-ORing PI2122 is a complete
full-function Active ORing solution with a
circuit breaker feature, integrating a highspeed
MOSFET controller and very low
on-state resistance MOSFET in the high
density thermally enhanced 5mm x 7mm
land grid array package. It is designed for
use in redundant power system architectures,
suitable for ≤5 Vbus applications
where added protection against load fault
the fourth calendar quarter 2008.
electronica: Hall A4 stand 538
Hall A5 stand 568
www.linear.com
7V, 12A solution with integrated back-toback
configured MOSFETs with an effective
6mOhm typical on-state resistance
enabling very high efficiency. It provides
very fast dynamic response to both input
power source and output load fault conditions,
typically within 140ns and 170ns
respectively, acting as a true bi-directional
switch. In addition to responding to
a reverse current fault condition, when
the PI2122 detects excessive forward
current, over temperature, under and
over-voltage faults, it will rapidly turnoff
the internal MOSFETs to provide a
load disconnect feature. The PI2122 also
provides a user programmable auto-retry
off-time during excessive forward current
fault conditions.
The PI2002 is a high-speed Active
ORing controller IC with a load disconnect
feature that functions similar to the
PI2122, but is designed for use with industry
standard back-to-back N-channel
MOSFETs.
The Cool-ORing solutions can substantially
reduce power dissipation by up
to ten times versus conventional diode
ORing solutions, eliminating the need for
unnecessary thermal management overhead,
while reducing board real estate
by over 50% and maintaining benchmark
dynamic response versus conventional
Active ORing solutions.
The discrete Cool-ORing controllers
are each available in two packages:
the 3mm x 3mm 10-lead TDFN and the
8-lead SOIC package.
conditions is required. The PI2122 is a www.vicoreurope.com
Power Systems Design October 2008
On The Right Track!
Safe solutions for tough applications
www.powersystemsdesign.com
COVER STORY
The railway traction market continuously demands space saving and improved performance for all
equipment and the transducers used in such applications must follow. Standards also have increasing
requirements for higher insulation and partial discharge levels in order to guarantee safety, better
immunity against external electrical, magnetic and electromagnetic fields for EMC protection, low
emission, excellent accuracy for example in case of energy metering application, and protection against
fire and smoke mandatory in railway applications.
Converters in these applications
require better characteristics
such as low influence in common
mode, low thermal drift, fast response
time, large bandwidth and low noise.
LEM has introduced the first, compact,
DC Class 1 accuracy voltage transducer
for the traction market. LEM’s new DV
technology is an innovative development
using known and tested components.
DV’s applications
Medium and high voltage railway applications
include:
• Catenaries with the different voltage
networks to be checked at the entrance
of the locomotive (AC with different
frequencies or DC catenaries voltage)
• On-board energy meters needing
voltage transducers to feed their voltage
input channels designed to receive any
traction network. Typically, they are located
at the circuit breaker level, where
high accuracy is required, even at lower
voltage.
• Substations where voltage transducers
monitor the DC voltages supplied to
the catenaries at the DC rectifier output.
LEM’s new technology DV transducer
is aimed at R&D engineers within
the railway industry (main converters
and sub-stations) and medium voltage
industrial applications. Target applications
include measurement of network
By Michel Ghilardi and Marc Schaerrer, LEM SA
voltages and in the DC link of the main
converters on trains. Mainly designed
for on-board railway applications like
traction or auxiliary converter, the DV
transducer can also be adapted to any
kind of other aggressive environment
requiring high performance, reduced
volume and reliability.
The DV’s high insulation level is
achieved by a LEM robust and proven
technology. It is significantly smaller
than any equivalent product on the market
today, measuring only 134 x 54.22
x 147.25mm (1069cc) and is only half
the size and weight of the earlier LEM
LV 200-AW/2/Voltage transducer which
uses closed loop Hall effect technology
on the same footprint. The DV models
are 100% compatible with the earlier
LEM LV 200-AW/2/Voltage and CV
4-Voltage models within the same footprint
mounting. This is desirable when
retrofits are required on older installations.
The large volume needed by the former
closed loop Hall effect and Fluxgate
technologies can be attributed to the
magnetic circuits necessary for operation.
The advantage of the electronicbased
DV technology is to minimize the
31

Four-Day
Power Supply
Design Workshop
Bordeaux, France at the Mercure Hotel March 30 - April 2, 2009
Learn first-hand from Dr. Ray Ridley, a leading power electronics industry
consultant and researcher. During his 28 years in the industry, he has taught
advanced design to thousands of engineers worldwide.The world’s
leading engineering companies in aerospace, semiconductors and
commercial applications send their engineers to the Workshop
to take their designs to the next level.
The Workshop focuses on theoretical and practical concepts
with hands-on experience. Learn to design, build and
measure switching power supplies in our
state-of-the-art travelling laboratory.
Study theory and design concepts each
morning, and build circuits and magnetics in the
afternoon. Learn how to use POWER 4-5-6,
the world’s most comprehensive design
software and receive your own
personalized copy for attending
the workshop.
Tuition is €2500 and includes training, lab
notes, POWER 4-5-6 software and lunch.
Reservations are now being accepted.
Only 24 seats are available at each workshop.
Download a registration form at www.ridleyengineering.com
Agenda
Monday Morning Lecture 8:30 - 12:00
Power Stage Topologies
Inductor Design
Saturation
Core Loss
Proximity Loss
Practical Design Procedures
Tuesday
Wednesday
Thursday
Morning Lecture 8:30 - 12:00
Transformer Design
Saturation
Leakage Inductance
Planar Magnetics
Proximity Loss
Multiple Output Cross-Regulation
Winding Capacitance
Practical Design Procedures
Gate Drive and Current-Sense Transformers
Morning Lecture 8:30 - 12:00
Simulation of Power Supplies
Small-Signal Analysis for Voltage-Mode Control
PWM Switch Model
CCM and DCM Operation
Right-Half-Plane Zeros
Loop Gain Criteria
Compensation Design
Morning Lecture 8:00 - 11:00
Current-Mode Control
Current-Mode Circuit Implementation
Current-Mode Problems
Current-Mode Advantages
Small-signal Analysis of Current-Mode Control
Subharmonic Oscillation
Current-Mode Feedback Design
WWW.RIDLEYENGINEERING.COM
Afternoon Laboratory 13:00 - 17:00
Design of Flyback Inductor/Transformer
Construction, Winding, Gapping Transformer
Impedance and Leakage Measurement
In-Circuit Testing
Snubber Design
Full Power Testing
Efficiency Measurements
Afternoon Laboratory 13:00 - 17:00
Design of Forward Inductor
Design of Forward Transformer
Construction, Winding, Gapping Forward Mag.
Impedance and Leakage Measurement
In-Circuit Testing
Snubber Design
Full Power Testing and Efficiency Measurements
Afternoon Laboratory 13:00 - 17:00
Measurement of Forward Control Characteristics
Output Impedance Measurement
Control Loop Compensation
Loop Gain Measurement
Stability Optimization
Step-Load Response Measurement
Afternoon Laboratory 12:00 - 15:30
Measurement of Flyback with Current-Mode
Compensating Ramp Addition
Control Loop Compensation
Loop Gain Measurement
Stability Optimization
Second-Stage Filter Design
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
Ridley Engineering UK Ltd. ~ 10 The Green ~ Bracknell, Berkshire RG12 7BG ~ UK ~ +44 (0)1344 482 493 ~ Fax: +44 (0)1344 204 632
Ridley Engineering, Inc. ~ 885 Woodstock Rd., Suite 430-382 ~ Roswell, GA 30075 ~ US ~ +1 770 640 9024 ~ Fax: +1 770 640 8714
Email: DRidley@ridleyengineering.com

34
COVER STORY
LEM’s new DV voltage transducer
magnetic circuit providing the isolation
and to integrate only electronic components
(amplifiers, resistors, capacitors,
A/D and D/A converters, micro-controllers,
etc.) The large heatsinks usually
installed on Hall effect and Fluxgatebased
voltage transducers have been
removed by reducing losses.
With electrical drives for railway locomotives
supplied from networks up to
3kV, the measurement signal needs to
be transmitted to electronic circuits at
low voltage for control and/or display
purposes. The transmission of power
and signals between a high voltage en-
vironment to a low voltage environment
requires specific insulation features.
DV’s description
To achieve this, LEM has designed a
new range of voltage transducers based
on a new patented technology which is
different to the traditionally used closed
loop Hall effect technology. The result is
the DV series voltage transducers that
cover nominal voltage measurements
up to 4200 VRMS. To operate, they only
need to be connected to the measuring
voltage, without inserting additional
resistors on the primary side, and a
standard DC power supply range of ±
13.5V to ±26.4 V.
With a primary voltage higher than
zero, the transducer consumes a
maximum of 23mA (maximum internal
consumption), plus the output current
(typically 50mA at nominal value), when
programmed with current output.
In comparison to the other methods
used to measure high voltages, this
provides considerable energy savings
on customer supply - for example, a
Fluxgate based voltage transducer
consumes between 35-50mA with no
primary voltage.
Based on LEM’s long experience in
current and voltage transducers for traction
application, the DV covers customer
requirements for nominal voltage
measurement to 4.2kV RMS. It features
a combination of all the advantages of
previous LEM products and fulfilment of
all new EMC requirements. This product
has been developed according to IRIS
standards:
• Low consumption of about 19-23mA
• Frequency bandwidth 12kHz
• Safety insulation 18.5 kV
This is followed by a digital encoder
producing a single serial signal enabling
data to be transmitted via one single,
isolated channel. Thereafter, an amplifier
feeds the signal to the primary side
transformer, transformer required to
Figures 1: Starting from the left of the diagram at the primary side, where input voltage might typically be ±4.2kV, the first
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
thermal drift. Then a sigma delta modulator converts the signal from analogue to digital as a 16-bit output.
Power Systems Design October 2008
provide the desired galvanic isolation.
Due to the high voltage environment, a
double core transformer is considered,
limited in size thanks to the considered
high digital working frequency. Windings
are wound into a PCB, similar in layout
to a planar transformer, which affords
product repeatability and assures component
behaviour.
The product is primarily designed for
onboard traction and stationary traction
substation applications. Within a
substation the insulation test voltage is
above 18kV for one minute for a working
voltage of 4.2kV, while onboard, the
insulation test voltage is max 13kV.
The transformer therefore needs to
withstand such a high test voltage,
while at the same time the lifetime of the
insulation can be guarantee by a partial
discharge test, where a voltage is applied
between the primary and secondary
to determine if there is a discharge,
which should measure less than 10 Pico
coulombs.
On the secondary side the bit-stream
is decoded and filtered by a digital filter.
Because the primary signal square wave
is distorted by the transformer, there is
a Schmitt trigger on the secondary side
of the transformer to restore it to square
wave. This is then fed into a decoder
and digital filter, the function of which
is to decode the data bit stream into a
standard digital value that can be used
in digital to analogue conversion within
the microcontroller. The recovered
output signal is completely insulated
against the primary (high voltage), and
is an exact representation of the primary
voltage.
The transducer can be easily adapted
for different ranges by modifying the
gain programmed by the microcontroller.
This does not require changes in the design
of the transformer or in the design
of the assembly of the circuit boards in
the housing. The microcontroller cancels
offsets and adjusts the gain by software,
and then converts the signal from digital
to analogue output. The micro-controller
transfers data from the digital filter to a
12-bit D/A converter with a transfer time
of around 6 μs. The analogue output
voltage is then filtered and converted
into a current (75mA full scale) using
www.powersystemsdesign.com
a current generator protected against
short-circuits.
The microcontroller also regulates a
DC/DC converter that creates internal
secondary regulated supply voltages
supplied by customer DC supply which
will typically be ±24V or ±15V, while
also supplying ±5V and ±3.3V to the
primary side sigma delta converter and
digital encoder. The additional circuitry
is shown as a group at the top of the
circuit schematic, with the frequency
of the DC to DC converter given by the
microcontroller.
The last block to the right of the
microcontroller is a voltage to current
converter for customers who prefer current
output, typically 50mA, in order to
comply with electromagnetic compatibility
(EMC) regulations. The lower impedance
current output is less prone to
interference from external electromagnetic
fields. A voltage output version
to 10V is also available, for example,
where the transducer is to be used with
shielded cable or with short connections
to customer electronics.
Main characteristics
Providing excellent overall accuracy
with ±0.3% of VPN at ambient temperature
and over its operating temperature
range from -40°C to 85°C, the DV shows
a low temperature drift resulting in an
overall accuracy of only ±1 % of VPN.
Initial offset at 25°C is 50μA max with a
maximum possible drift of ±100μA over
the operating temperature range. Sensitivity
error at 25°C is ±0.2%. The microcontroller,
used among other things for
D/A conversion, is also useful for offset
and gain adjustment during production,
enabling these parameters. Linearity is
only ±0.1%.
The DV transducer’s typical response
time (defined at 90% of VPN) against a
voltage step at VPN has a delay of 48μs
(Max 60µs). Other closed Loop based
on Hall effect voltage transducers have
a response delay of several hundred
microseconds. As a result of the fast
response time, a large bandwidth has
been verified at 12kHz at -3 db (Fig. 3).
Mechanical and standards
The DV’s modular approach allows
easy adaptation with various connec-
COVER STORY
tions available for the primary side, e.g.
terminals or isolated cable, and any kind
of connection for the secondary side like
connectors, shielded cables, terminals
(threaded studs, M4, M5, UNC etc.) according
to customer specifications.
The DV models have been designed
and tested according to latest recognised
worldwide standards for traction
applications. The EN 50155 standard
“Electronic Equipment used on Rolling
stock” in railway applications is the
standard of reference for electrical, environmental
and mechanical parameters.
It guarantees the overall performances
of products in railway environments.
LEM’s main production centres for
traction transducers are IRIS certified -
essential for companies supplying the
railway market. DV transducers are CE
marked as a guarantee of compliance
to the European EMC directive 89/336/
EEC and low voltage directive. They
also comply with the derived local EMC
regulations and with the EN 50121-3-2
standard (railway EMC standard) in its
latest update, with EMC constraints
higher than that of the typical industrial
application standards.
The EN 50124-1 “Basic requirements
- clearances and creepage distances for
all electrical and electronic equipment”
standard has been used as a reference
to design the creepage and clearance
distances for the DV transducers versus
the required insulation levels (rated
insulation voltage) and the conditions of
use. Clearance is the shortest distance
in air between two conductive parts and
creepage is the shortest distance along
the surface of the insulating material
between two conductive parts. Pollution
degree is application specific and is a
way to classify the micro-environmental
conditions having an effect on the insulation.
Overvoltage category is also application
specific and characterises the
exposure of the equipment to overvoltage.
Partial discharge (PD) is the dissipation
of energy caused by the buildup
of localised electric field intensity.
Electric discharges partially bridge the
insulation. Failure is by gradual erosion
or ‘insulation, leading to puncture or
surface flashover. The partial discharge
35

36
COVER STORY
Figures 2&3: show the transformer response time and frequency bandwidth respectively, and in the case of energy measurement,
phase is as important as amplitude, because you can get phase shift even at frequencies below 1kHz, and what
is important for traction customers is measurement without delay.
test verifies that no partial discharges
are maintained in the solid insulation at
the highest steady-state voltage, at the
long-term repetitive voltage.
The higher the extinction partial discharges
voltage (> 5kV) is the better, as
no discharges happen during the normal
defined function. The partial discharges
level is defined at 10 pC.
Accelerated tests have been performed
to estimate failure rate including
temperature cycles and complete char-
acterisation of the product according
to standards. Thanks to an innovative
design using the insulation transformer,
the DV models guarantee insulation and
PD levels for high voltage applications
up to 5kV peak.
In the past the commutations of the
semiconductors were slow, which implied
low dv/dt). Now new technologies
like IGBT and MOSFETs provide higher
dv/dt between primary and secondary.
The secondary is generally connected to
ground for safety reasons. The primary
Figuer 4: Due to the DV’s low parasitic capacitance, the effect of dynamic common
mode is reduced.
is the measurement of differential voltage,
but voltage can float. The potential
change on the primary will cause
a perturbation at the secondary. This
cannot be filtered because it will reduce
response time, so the parasitic capacitance
between primary and secondary
has to be reduced in the design.
Mainly designed for medium and high
voltages on-board railway applications
like propulsion or auxiliary converter,
DV transducers are also suitable for any
kind of rugged environments, requiring
good performance in terms of accuracy,
gain, linearity, low initial offset, low thermal
drift, etc. Featuring high immunity to
external interferences, generated by adjacent
currents or external perturbations
for example, and high immunity against
high voltage variations, DV transducers
offer excellent reliability. The DV is the
first DC class 1 accuracy voltage transducer
on the market providing outstanding
performance over a large voltage
and temperature range. It can also be
used for energy monitoring and billing
purposes.
www.lem.com
Power Systems Design October 2008
In the larger-scale PV system shown
in Figure 8 below, several inverters
are combined in multiple racks for a
total output power of 500kW. One of the
inverters is pulled out of the rack, demonstrating
the easy replacement. The
unit in the middle is the monitoring unit,
used to control all inverters and monitor
the performance of the subsections
www.powersystemsdesign.com
Solar Power Shines!
of the solar power plant. There are also
systems that can handle up to 200kW
in one (larger) rack unit, at increased
power density.
As shown above, the front end of the
inverter has a distinct task. In order for
the back end to perform the DC-to-AC
conversion with high efficiency, it is best
to “feed” it with a DC voltage that is by
a certain margin higher than the maximum
required output voltage, so that
the backend only needs to perform a
step-down function. But the output voltage
of one panel is typically 50 to 80V,
so several panels must be connected in
a series to achieve a high input voltage.
And, the voltage will depend on the
solar radiation density – very quickly,
a pretty complex situation is achieved.
The challenges are:
Solar Power
Implications of solar panel technologies and
system power ranges
Here, we continue (See September 2008 PSDE, page 38) with the technology of harnessing solar
energy that is re-shaping the energy generation scene and is having a dramatic effect on the way
semiconductors can be applied to solve the problems of environmental pollution and the escalating
cost of conventional sources.
By Alfred Hesener, Director for Applications and Marketing, Fairchild Semiconductor, Europe
Figure 8: Rack with several higherpower
inverters working in parallel.
Part II
• The input voltage can vary over a
wide range. If the number of panels
chosen and connected in series is so
high that the input voltage is higher
than the output voltage under all
conditions, then the maximum input
voltage is so high that power switches
with very high breakdown voltages
are needed (which is expensive and
lowers efficiency), and the handling
and cabling is more difficult (making
the system less reliable). A compromise
is to choose a smaller number
of panels in series, so that the voltage
cannot become so high, but in order to
provide output power at lower radiation
levels a boost converter is needed.
The total efficiency and the yield of the
system can be shown to actually be
higher, even though the system is more
complex.
37

38
Solar Power
Figure 9: MPP tracker (Source: Photon).
• In a larger system, several strings of
series-connected panels are connected
to an inverter. If one of the panels is
shaded or the cells have a lower yield
to begin with, the output voltage of
this string will be lower. In order for
this string to contribute to the output,
individual boost converters are used for
each string, compensating individual
variations, and operating each string in
its maximum power point.
• As individual panels have different
MPPs, they must be sorted before connecting
them together, to ensure their
MPPs match, or even the best inverter
in the world will not be able to maximize
the yield.
The MPP tracking function requires a
multiplication of the voltage and current,
to calculate the output power. Then,
the load impedance is varied slightly,
and the system moves in the direction
of higher power drawn from the panels.
This algorithm is then repeated. As the
radiation usually changes slowly, a high
speed loop is not required.
Figure 9 shows an example of the
MPP tracker matching at the input,
that means, how close the front end
converter is able to match its input
impedance to the output impedance of
the panels. The horizontal scale is the
nominal power; the vertical scale the
input voltage. Higher efficiency areas
are shaded in red. The input impedance
is controlled within the feedback loop
of the MPP tracker, so any deviation is
signaled through a lower efficiency and
implies something this control loop cannot
regulate away – an implicit limitation
of the inverter, and the topologies
and components chosen. Another root
cause can be measurement errors in
determining the input current and
voltage, as well as limitations in the
resolution of the A-to-D converters
and controllers.
Figure 10 shows the total conversion
yield of the same inverter, disregarding
the mismatch at the input,
but looking purely at the AC output
power versus the DC input power.
The horizontal scale is the nominal
power, and the vertical scale shows
the input voltage. This example
shows an inverter that actually works
quite well, particularly with high input
voltages, but as the voltage drops the
yield also goes down. On the left hand
side the inherent energy consumption of
the inverter can be seen to reduce the
yield. The input overcurrent protection
can be seen in the lower right corner.
As can be seen from the diagram,
the “harder” the front end converter
needs to work, the lower the yield. At
high input voltages, very little additional
boost needs to be provided, so the corresponding
power dissipation is lower.
However, at lower input voltages, a high
AC current ripple in the input translates
to larger losses. Improvements in the
boost converter would first of all improve
the overall efficiency, and secondly,
move the area of maximum efficiency
to lower input voltages, providing a
better match to the panels. As panels
do have a non-zero source resistance,
the output voltage under load can be
significantly lower than the no-load voltage,
particularly for thin-film panels. So,
this reduced voltage level is where the
maximum yield of
the inverter should
be and not at very
high input voltages
as the yield will be
wasted with this
mismatch.
It is interesting
to note that
the best tracking
is achieved at an
input voltage of
390V, precisely the
voltage chosen at
design to turn-off
the boost converter,
and a clear
distinction can be
seen at the handover point between the
two-stage and the single-stage operating
mode. The inefficiencies in the tracking
as well as power conversion are due
to a sub-optimal inverter that cannot
transform a required input impedance
value well enough to a certain output
impedance. In the upper left hand corner,
a lower tracking and also efficiency
is visible, indicating the main inverter
cannot handle low input currents at high
voltages very well. This may be caused
by power switches with too high output
capacitances, as the losses are proportional
to C*U 2 . As the current in the inverter
increases (moving in the diagram
to the right), the proportion of switching
losses is getting smaller compared to
the conduction losses, so the efficiency
actually improves, although the power
dissipation goes up.
As can be seen on the left hand side
with the vertical yellow areas in Figure
10, the yield is lower at low power, probably
due to this inverter having higher
than necessary switching losses in the
boost converters. At the lower right
corner, at a combination of low input
voltage and high power, the input current
becomes very large so the input DC
over current protection will switch off
the inverter. On the right hand side, at
power levels over 115%, the inverter will
turn off as well.
In order to improve the performance,
and have larger parts of the diagram
“red”, various measures can be implemented.
Apart from the obvious optimization
in passive components, the boost
Figure 10: Total conversion yield (Source: Photon).
Power Systems Design October 2008
Figure 11: The correct gate drive of the power switches is crucial in many respects.
diodes need to be carefully selected
for low switching losses (improving the
performance at low input power, the left
side of the diagram), and for low forward
voltage drop (to improve the yield at
high input currents, the lower part of
the diagram). The StealthTM II diodes
from Fairchild Semiconductor or silicon
carbide diodes can provide this optimization.
The power switches in the boost
converter, usually MOSFETs, also need
to be carefully chosen. At low input voltages,
the current through the switches
is causing conduction losses due to
the high duty cycle, so low RDSON is
important – in fact, it is not uncommon
to see several large MOSFETs in TO-247
packages connected in parallel.
Further improvements can be gained
with a careful choice of operating
mode of the boost converter. Continuous
mode conversion is chosen,
to minimize AC losses, and the lower
ripple currents allow for reduction of
unwanted overhead in the system.
However, this is a hard-switching
system, so power MOSFETs with a
low output capacitance should be
chosen. This however contradicts
somewhat with the requirement for low
conduction losses in the switch, to be
obtained with a larger device. Here,
a good compromise can be found in
Fairchild’s SuperFET devices that
can at the same time provide a “fast”
body diode at no RDSON penalty.
This also helps at the lower right hand
corner of the diagram, as at low input
voltage and high power the duty cycle
of the converter is quite long, with high
www.powersystemsdesign.com
currents in the switch.
The value of Rgate plays a significant
role in the performance of the system.
The lower this resistor becomes, the
faster the MOSFET will be switching
(provided the gate driver has sufficiently
low output impedance). Faster switching
corresponds to higher dI/dt and dv/dt,
increased electromagnetic emission
(EMI), and can lead to breakdown of
the components, reducing reliability. If
the gate resistor value is increased, the
switching speed is reduced, but this
means the overlap between current in
the device, and voltage across the device,
is increased, and so are the switching
losses. In other words, the switch
behaves less and less as a switch, but
spends more and more time in the linear
region, causing power dissipation. In
conclusion, the gate resistance values
need to be finely tuned for lowest power
dissipation and EMI.
To improve performance even further,
resonant or quasi-resonant topologies
can be used, although they can be challenging
to implement for a wide input
voltage range and still operate at ZVS
(“zero voltage switching”) or ZCS (“zero
current switching”). Another topology to
improve performance is the interleaved
boost converter. Here, multiple converters
are working in parallel, out-of-phase
with each other, and it can be shown
that the ripple current in the output can
be reduced. And, if the input voltage is
high enough, the boost converter can be
turned off completely and bridged e.g.,
with a relay, to further reduce losses.
Solar Power
The inverter or DC-to-AC section of
the inverter can be built with many different
topologies, quite a few of them
proprietary to some of the companies
building inverters. One of the “classical”
topologies consists of using a
full bridge, driving output inductors to
reduce EMI. Here, some of the devices
can be switched at line frequency
whereas others are switched with the
conversion frequency – if done cleverly,
the first devices can be chosen
for lowest conduction losses, like the
Non Punch Through(NPT) Fieldstop(FS)
IGBTs from Fairchild Semiconductor,
whereas the latter should be chosen for
lowest switching losses, e.g. the new
NPT Field Stop Trench devices from
Fairchild Semiconductor. Here, a combination
of different IGBTs or even IGBTs
and MOSFETs can help to improve the
overall yield. And to properly drive the
power switches, optically isolated gate
drivers like Fairchild’s FOD3180 can be
used, improving the system reliability
where high dv/dt can suddenly occur,
e.g., in the case of a grid fault.
In applications such as solar inverters,
where the key performance parameter
is the conversion efficiency, improvements
in switching device performance,
through the use of IGBTs, MOSFETs
and diodes are very important. Here,
the voltage drops and switching energy
losses can still be improved, although in
order to realize the potential gains, more
brainpower has to go into how to drive
the switches properly, to avoid parasitic
oscillations and overvoltages: the two
biggest enemies of high efficiency and
robustness. Here, integration of subsystems
into intelligent power modules can
really help! Due to the close proximity
and ideal matching of driver and power
switch, the best possible switching
behavior can be realized repeatedly.
Fairchild Semiconductor is driving the
state-of- the-art in both power switch
technologies as well as module integration
to support further performance
improvements in these green high-tech
applications.
www.fairchildsemi.com
39

Avoiding Current Spikes
The relationship between voltage
and current is similar to the relationship
between water pressure
and water flow. Higher water pressure
represents higher voltage and higher
water flow represents higher current.
One can observe flow or pressure, both
or neither, depending on the system
under consideration. For example, when
compared to a standard garden hose,
a fire hose has high pressure and high
flow. Contrast this to the Amazon River
which has a much higher flow and lower
pressure. An example of high pressure
and no flow is the water behind a dam.
The dam acts like an open switch in an
electronic circuit storing water (voltage)
for immediate release.
To fully understand the difference
between incandescent bulbs and
semiconductors such as LEDs, let us
consider voltage driven devices for a
minute. The filament of an incandescent
bulb is simply a resistor. When electrically
powered, the filament heats to near
white hot temperature - more than
5,800°F or 3,250°C. The high temperature
of the filament generates the light.
When first powered, the filament is cold
and has a much lower resistance than
when it is hot. According to
Ohm’s law, V = I R, the current in the
filament is higher when the bulb is first
turned and the filament is cold. This cur-
www.powersystemsdesign.com
with LEDs
rent is known as the “in-rush” current.
Very quickly after turn-on, the filament
heats to its operating temperature. As
the filament heats, the resistance goes
up dramatically and the current drops
proportionately. In much less than a
second, the filament resistance stabilizes
and the current is constant.
Due to the characteristics of filaments,
driver designs for bulbs expect
an in-rush current as part of their
performance. As long as the voltage is
constant, bulbs tolerate these current
fluctuations. However, bulbs are very
sensitive to voltage variations. Different
sources cite different levels of sensitivity,
a recent check of Wikipedia stated
the lifetime of a bulb was dependant on
the inverse of the sixteenth power of the
voltage. In other words, an increase in
voltage of only 5% could have a dramatic
effect on the lifetime of the bulb.
Using the equation:
Lifetime bulb = (105% V rated / 100% V rated) -16
(representing a 5% increase in Voltage)
Lighting
Hot switching can destroy any LED.
Well designed drivers are the simple solution
Unlike many illumination sources, such as incandescent bulbs that are voltage driven, LEDs are current
driven devices. This distinction requires different considerations when designing and using driver
electronics. Here, we compare incandescent bulbs to LEDs to highlight this subtle difference.
By Pat Goodman, Technical Director, Philips Lumileds, San Jose, California
Figure 1: Typical switched circuit.
Lifetime bulb = (1.05) -16
Lifetime bulb = 45.8% of initial lifetime
Simply stated, a 5% increase in voltage
decreases the bulb lifetime by more
than half. Therefore, for a robust product
performance, incandescent bulbs depend
on well-regulated voltages while
being tolerant to some current fluctuations.
LEDs are current-sensitive devices.
However, although slight changes in
current, such as the 5% mentioned
above, do not affect LEDs nearly as
much as similar changes in voltage affect
filaments in bulbs, it is still important
that designers consider transient
peak currents when implementing LED
driver circuits. Specifically, there are a
few areas where switching on the LED
causes current spikes that exceed the
circuit design current by many times.
Fortunately, “forewarned is fore-armed”
as they say, and some simple considerations
eliminate occurrences of these
current spikes.
41

42
Lighting
Figure 2: Hot switching performance
The terms “Hot Switching” and “Hot
Plugging” refer to the act of inserting a
device (mechanically or electrically) into
a powered electronic circuit. An example
of “Hot Plugging” is turning on the
socket before screwing in a bulb. When
inserting the bulb into the socket, it
lights immediately upon contact with the
bottom of the socket. This is because
there was energy in the metal contacts
in the socket. A similar effect occurs
when connecting a semiconductor, from
high-end computer chips to LEDs, to a
hot circuit. However, in the semiconductor
case, this “hot-switch” can result in
an in-rush current that can damage the
device.
Going back to water example, imagine
the water in a hose connected to your
house. With the faucet on but the nozzle
closed, the pressure in the hose is at
a maximum. When first opening the nozzle,
this water pressure surges though
the small opening until the flow drops
to the amount regulated by the nozzle.
Everyone has probably seen the “spurt”
of water when first opening a nozzle.
The time it takes for the flow to drop
to the regulated level is sufficiently fast
that most of us do not care about the
“spurt” (although it’s great if you need
that little extra distance in water fight!).
Similarly, with electrical circuits, the time
it takes for a current to regulate is too
fast for us to notice. In fact, we usually
want things to turn on immediately.
However, semiconductors react millions
of times faster than humans do. A very
short current pulse – sometimes just a
few milliseconds long – can destroy a
semiconductor chip.
One might ask the question “How
much power is stored in a simple
switched circuit?” The easy answer is
“A Lot”, enough to cause damage to the
semiconductor. The full answer takes
a little more explanation. To clearly
demonstrate the effect, let us consider
a simple circuit consisting of a current
source driver, a switch, and a string of
n LEDs wired in series (figure 1). In this
example, assume the maximum V f of
the LED string is 36V. The driver specifications
include forward current (If) =
Figure 3: Soft start example.
350mA at a 50V maximum, similar to a
typical 25W supply.
The circuit controls the current to
350mA when the switch is closed.
However, when the switch is open, the
current flow stops and the circuit is unable
to regulate itself. In a short time,
the voltage between the output of the
power supply (PS) rises to the compliance
voltage shown on the specification
sheet or +50V. This is easily proven
by measuring the voltage between the
power supply terminals with a voltmeter.
Remembering our water example, there
is stored charge in the system similar to
stored water in pipes. The output of the
power supply, and the wires, act like a
Power Systems Design October 2008
very large capacitor by storing charge
analogous to the manner pipes and the
hose store water. When the switch is
closed, this charge flows rapidly through
the circuit until the power supply begins
to self-regulate. However, the total
stored charge in the wires may be sufficient
to destroy a semiconductor such
as an LED.
Preventing the destructive current
surge is a matter of design. The simple
statement of “No Hot Switching”, “Soft
Start”, or “Cold Switched” is sufficient
to assure no current surge. To a lay person
the difference between the surging
current of a hot-switched unit and a unit
with a soft start is best seen in a chart.
The chart plots current (on the left y-axis)
and voltage (on the right axis) versus
time. There are three points of interest:
before the device is switched on; during
the time it takes the power supply to
regulate (usually a few milliseconds);
and, after the current regulates.
By using Ohm’s Law, where the Volt-
PowerPack PowerPack
www.powersystemsdesign.com
age is equal to the current multiplied by
the resistance or V = IR, we can calculate
Current through the LED. From the
graph, it is easy to see how the voltage
transient behavior injects a large current
spike (in this case, three times the design
value) into the LED. These current
spikes can cause permanent damage to
any semiconductor (ICs, microprocessors,
and LEDs too).
By specifying a soft start, these ugly
current spikes can be easily avoided.
A soft start circuit assures the drive
wires are at zero volts when the switch
is open. With the closing of the switch,
the current rises from zero to the design
parameters without the current spike
shown before. This is analogous to the
leaving the nozzle on the hose open
while turning on the water at the faucet.
It takes a little time for water to reach
the nozzle, and when it does, the flow
rises to the desired amount.
We have shown how improperly
specified driver circuits can and will
A Powerful
Combination
PowerPack and ePowerPack is a new
advertising program in print and online designed to
promote your company’s new products, seminars,
and announcements while driving traffi c to your
company’s website.
Advertisers receive a 100 word listing, plus product
photo and url link in print to 20, 357+ subscribers
of Power Systems Design’s magazine and online
through ePowerPack e-newsletter which is delivered
every month to an audience of 24,000 power electronic
engineers in Pan Europe and 32,000 power
design engineers in North America. To participate
contact: Julia@powersystemsdesign.com
Power Systems Design
Power Systems Design PowerPack
Lighting
introduce semiconductor damaging
current spikes. Properly specifying the
driver assures effective current regulation.
Designing for a “Soft Start” is not
an unusual request, hard to do, or more
expensive. A search of National Semiconductor’s
WEBBENCH ® tools site
revealed they have over 200 products in
their catalog that, by design, are “Soft
Starting” ICs to drive LEDs and other
semiconductors. Further, with WEB-
BENCH ® one can immediately download
a reference design with complete BOM
based on your chosen Luxeon LED and
operating parameters.
Other driver manufacturers also sell
driver electronics that are specifically
designed to work with high-power LEDs
such as the LUXEON I, LUXEON III,
LUXEON V, LUXEON K2, LUXEON Rebel
and LUXEON K2 with TFFC, and “Soft
Start” is only one driver characteristic of
interest. But it is a critical one.
www.philipslumileds.com
Power Systems Design
PowefulComboAd.indd 1 3/13/08 5:58:47 PM
43

46
Powering Powering Freight Freight & Transportation
& Transportation
Transport and Automotive
Applications Benefit from
Multiphase Boosters
Design for reduced EMI, higher efficiency,
faster transient response
High power step-down DC/DC converters have long benefited from multiphase operation. But all
the advantages of multiphase operation, such as reduced input and output ripple currents, lower
output noise and lower component stresses, can also be realized in step-up applications. Many of the
controllers used in step-down applications can also be used in step-up applications and generally have
2 phases, which may not provide enough output power or have the ability to keep the phase currents
balanced. They also usually need extra support components, like gate drivers, extra bias voltage and an
external error amplifier to complete the circuit.
By Bruce Haug, Product Marketing Engineer and Tick Houk, Design Engineer,
Linear Technology Corporation
Until recently, most high power
step-up converters have utilized
non-optimized solutions due to
the lack of an available multiphase boost
controller. The most common nonsynchronous
2-phase step-up converter
solution has been to use the top-side
drivers of a 2-phase synchronous stepdown
controller configured to drive two
low-side power MOSFETs 180 degrees
out-of-phase. Another solution has been
to use 2 or more single-phase step-up
controllers and an external clock circuit
to achieve the required channel-tochannel
phase relationship. Other nonoptimized
solutions have used either
push-pull or dual interleaved forward
controllers in a non-isolated step-up
configuration. However, all of these solutions
suffer from significant drawbacks
which limit their utilization in many of
today’s demanding applications.
In the automotive environment, the
next generation of low emissions diesel
fuel injection systems requires up to
2 amps of output current at an output
voltage in the 70V to 110V range, and
delivered from a 12V battery that can
vary from 9V to 28V. This input-tooutput
voltage conversion requires a
boost converter capable of greater than
92% duty cycle with constant frequency
operation.
Furthermore, high power car audio
amplifiers often need a main supply rail
in the 25V to 35V range with the ability
to supply peak power levels approaching
1000W, making multiphase operation
essential. By splitting the power
stage into multiple paralleled phases,
thermal stress is reduced on the power
components, thereby reducing output
voltage ripple and noise, allowing the
use of smaller output capacitors, and
improving system efficiency.
As power densities continue to rise,
multiphase boost designs become a
necessary option to keep input currents
manageable, increase efficiency and increase
power density. With mandates on
automotive energy savings more common,
a multiphase converter topology
may be the only way to achieve these
design objectives. A 2-phase or higher
phase converter built around Linear
Technology’s LTC3862, can demonstrate
the benefits of this type of approach.
A Multiphase Solution
The LTC3862 is a non-synchronous
multiphase controller capable of operating
in boost, SEPIC and flyback topologies.
This controller utilizes a constant
frequency, peak current mode control
Power Systems Design October 2008
The AP300 Analyzer and POWER 4-5-6 Software are designed
specifically for the power electronics engineer. Now, they
communicate with each other to show measurements overlaid
on theoretical curves.
The analyzer has advanced features including a high power
output, variable source vs. frequency curve, and high noise
immunity from 0.01 Hz to 30 MHz.
POWER 4-5-6 greatly accelerates your design process in
topology choices, magnetics, and control. A special version
of the software predicts the response of your power supply
and compares it with data collected from the AP300.
Each product is the best available in the industry. Together,
they will take your design and testing skills to the next level.
WWW.RIDLEYENGINEERING.COM
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
Ridley Engineering UK Ltd. ~ 10 The Green ~ Bracknell, Berkshire RG12 7BG ~ UK ~ +44 (0)1344 482 493 ~ Fax: +44 (0)1344 204 632
Ridley Engineering, Inc. ~ 885 Woodstock Rd., Suite 430-382 ~ Roswell, GA 30075 ~ US ~ +1 770 640 9024 ~ Fax: +1 770 640 8714
Email: DRidley@ridleyengineering.com

48
Powering Freight & Transportation
Figure 1: A Two-Phase, 72V Output, Low Emissions Automotive Fuel Injection Boost Converter Using the LTC3862-1.
scheme with its two power stages operating
180 degrees out-of-phase. Each
power stage is comprised of a single
inductor, MOSFET, Schottky diode and
current sense resistor. The two phases
are balanced closely with a tight current
limit threshold and a highly accurate
transfer function from the ITH pin (the
output of the error amplifier) to the current
comparator sense inputs, both from
channel-to-channel and chip-to-chip.
Because of this, the peak inductor current
matching is kept accurate, forcing a
balanced current in multiphase applications.
In a two-phase converter, only one
LTC3862 IC is required, and the two
output stages are driven 180 degrees
out-of-phase. In a 3-phase converter,
two LTC3862 chips are needed (2
channels from the master and 1 channel
from the slave) and the output
stages are driven 120 degrees out-ofphase.
Similarly, a 4-phase converter
utilizes 2 LTC3862 IC’s with each
channel running 90 degrees out-ofphase.
And so on until a 12 phase
application, where 6 chips would be
used, with each channel operating
30 degrees out-of-phase. By splitting
the current into multiple power paths,
conduction losses can be reduced
and thermal stresses can be balanced
between a larger number of components
and over a larger area on the board,
and output noise can be significantly
reduced. Conversely, for a given output
voltage ripple, multiphase operation will
result in a smaller total output capacitance,
which is especially important in
high voltage applications where the voltage
coefficient of the output capacitor
typically reduces the effective capacitance.
The LTC3862 contains two PMOS
output stage low dropout (LDO) voltage
regulators, one for the powerful onboard
gate drivers (which contain 2.1
Figure 2: LTC 3862 Current Sense Circuit.
Ohm PMOS source transistors and 0.7
Ohm NMOS sink transistors) and one
LDO for the low voltage analog and
digital control circuitry. Low dropout
operation allows the input voltage to dip
to a lower value before circuit operation
is affected. This is especially important
in automotive applications, where the
cold cranking of an engine can result
in a battery voltage droop to as low as
4V. The LTC3862 provides a 5V gate
drive for logic level MOSFETs and the
LTC3862-1 provides a 10V gate drive
normally required for higher output voltage
applications.
A Low Emissions Diesel Fuel
Injection Power Supply
Figure 1 illustrates a boost converter
designed for low emissions diesel
fuel injection systems. This converter
operates over a wide input voltage
range to accommodate the variation
of an automotive battery, from a cold
crank condition to a double battery
connection for jump starts. Because
of the wide input voltage range (8.5V
to 36V), the converter must be able
to operate at very high duty cycles
and still maintain constant frequency
operation. The LTC3862 has a
minimum on-time of approximately
180ns and a maximum duty cycle of
96%, with both of these parameters
Power Systems Design October 2008
being user programmable. The operating
frequency can be programmed from
75kHz to 500kHz using a single resistor,
and a phase lock loop can be used
to synchronize the operating frequency
to an external clock source. For the
example, the power MOSFETs used in
Figure 1 are the HAT2267H from Renesas,
a 57μH inductor with a saturation
current rating of 5A, and a total output
capacitance of only 107μF is necessary.
The output capacitance consists of two
47μF aluminum electrolytic bulk capacitors
connected in parallel with six low
ESR 2.2μF ceramic capacitors, in order
to meet the output voltage ripple and
RMS current requirements. This con-
www.powersystemsdesign.com
Powering Freight & Transportation
figuration also limits the output voltage
ripple to only 500mV.
This circuit operates with a peak efficiency
of 96% at an input voltage of
32V. Because a single-ended boost converter
regulates the current in the source
of the low-side switch, the maximum
current that can be delivered to the
load is a function of the input voltage.
As a result, this converter is capable of
delivering 0.5A to the load at an input of
8.5V, 1.5A at an input of 24V, and 2A at
an input of 32V to 36V.
The LTC3862 features two pins, CLK-
OUT and PHASEMODE that allow mul-
Figure 3: A 12V Input, 24V/5A Output 2-Phase Car
Audio Power Supply Using the LTC3862, and Its
Associated Efficiency Curve.
tiple ICs to be daisy-chained together
for higher current multiphase applications.
For a 3- or 4-phase design, the
CLKOUT signal of the master controller
is connected to the SYNC input of the
slave controller in order to synchronize
additional power stages for a single high
current output. The PHASEMODE pin
is used to adjust the phase relationship
between channel 1 and CLKOUT, as
summarized in Table 1. The phases are
calculated relative to the zero degrees,
defined as the rising edge of the GATE1
output. In a 6-phase application, the
CLKOUT pin of the master controller
connects to the SYNC input of the 2nd
controller and the CLKOUT pin of the
49

50
2nd controller connects to the SYNC
input of the 3rd controller.
Additional Features
The LTC3862 error amplifier is a
transconductance amplifier, meaning
that it has high DC gain and high output
impedance. This style of error amplifier
greatly eases the task of implementing
a multi-phase solution, because the amplifiers
from two or more controllers can
be connected in parallel. In a multiphase
application requiring more than one IC,
all of the FB pins should be connected
together and all of the ITH pins should
be connected together. The composite
transconductance of the error amplifier
is simply the sum of the number of ICs
connected together, multiplied by the
660μS of each amplifier. This parallel
connection of error amplifiers is not
possible with control ICs that use a true
operational amplifier, since this amplifier
type has a very low output impedance.
In addition to using parallelable error
amplifiers, the transfer function from
the ITH pin to the current sense comparators
is very accurate, in order to
provide the best channel-to-channel
and chip-to-chip current sense threshold
matching possible. This phase-tophase
current matching is especially
important in high current applications,
where resistive losses are proportional
to the square of the current. Minimizing
the mismatch between channels, results
in a balanced thermal design, which
prevents hot spots on the PCB and possible
thermal runaway.
The LTC3862 has a maximum current
sense threshold of each phase of 75mV,
which allows for a relatively lower power
sense resistor, reducing the circuit size,
increasing efficiency and eliminating the
need for a current sense transformer. It
also includes leading edge blanking for
the current sense inputs, so an external
Powering Freight & Transportation
RC filter is not required. Nevertheless,
some users may benefit from adding an
external filter as shown in Figure 2. If
external RC filters are used on the current
sense inputs, the filter components
should be placed as close as possible
to the SENSE pins, and the connections
to the sense resistor should run parallel
to each other and kelvin-connect to
the resistor in order to avoid parasitic IR
drops. The SENSE+ and SENSE- pins
are high impedance inputs to the CMOS
current comparators for each channel.
Programmable Blanking
The Blank pin on the LTC3862 allows
the user to program the amount of leading
edge blanking at the SENSE pins.
The purpose of leading edge blanking is
to filter out noise on the SENSE at the
leading edge of the power MOSFETs at
turn-on. During the turn-on of the power
MOSFET the gate drive current, the discharge
of any parasitic capacitance on
the SW node, the recovery of the boost
diode charge, and the parasitic series
inductance in the high di/dt path all contribute
to overshoot and high frequency
noise that could cause false-tripping
of the current comparator. Providing a
means to program the blank time allows
users to optimize the SENSE pin filtering
for several applications and can be set
to a minimum on-time of 180ns, 260ns
or 340ns.
An Audio Amplifier Boost Converter
Supply
Figure 3 illustrates a 2-phase car
audio power supply that operates
from a 5V to 24V input and produces a
24V/5A output. The wide input voltage
range covers an automotive input
voltage range and the efficiency curves
are also shown reaching up to 96.5%.
This circuit can be easily extended to
3-, 4-, 6- or 12- phase operation for
higher power applications, with minimal
modifications to the basic design. This
Table 1: Programming the Phase Relationship between Channels.
multiphase boost converter protects the
load from mild overload conditions by
imposing a current limit on each phase
(boost converters are typically not short
circuit proof due to the diode and inductor
connection from input to output).
Audio applications have short-duration
peak power demands that are much
higher than the average output power.
Therefore, the current limit must be set
high enough to satisfy these peak power
requirements.
In order to maintain constant frequency
operation and a low output ripple
voltage, a single-ended boost converter
is required to turn off the power
MOSFET switch every cycle for some
minimum amount of time. This off-time
allows the transfer of energy from the inductor
to the output capacitor and load.
Having a high maximum duty cycle is
desirable, especially in low VIN to high
VOUT applications. The maximum duty
cycle for the LTC3862 is 96% with the
DMAX pin connected to ground. For
other topologies, such as a non-isolated
flyback converter, it is desirable to limit
the maximum duty cycle in order to balance
the volt-sec of the transformer. The
LTC3862 has a maximum duty cycle
that is user-programmable. By floating
the DMAX pin, the duty cycle is limited
to 84%. Connecting the DMAX pin to
the 3V8 supply pin limits the duty cycle
to 75%.
Conclusion
The reduced ripple currents and multiphase
operation allows an LTC3862
based design to have reduced EMI,
higher efficiency, faster transient response,
provide a wider selection of
off-the-shelf components and increase
power density when compared to single
phase alternatives. Multiphase operation
results in lower component stresses,
smaller input and output capacitance,
smaller solution size, better thermal
management, and lower output noise.
With its programmability up to 12 phases
using multiple daisy-chained controllers,
the LTC3862 serves the needs of
step-up power supplies from 100W to
1000W in automotive fuel injection systems
and high power audio amplifiers.
www.linear.com
Power Systems Design October 2008
www.circuitprotection.com
Cure for the Uncommon Power Source
Barrel jacks are a simple and effective way of connecting portable electronics to
an external power supply. But what happens when the user plugs into a supply
operating at the wrong voltage? Or what about when the supply is dirty and full
of nasty voltage surges, as is often the case when power is supplied from an
automobile power jack? Raychem Circuit Protection PolyZen devices can help
protect your DC power ports by clamping excess voltages and smoothing
inductive voltage surges. The PolyZen device's unique polymer-protected
precision Zener design can help cure these all-too-common power problems.
To learn more, visit www.circuitprotection.com/polyzen.
Features
• Overvoltage transient suppression
• Stable Vz vs fault current
• Time delayed, overvoltage trip
• Time delayed, reverse bias trip
• Power handling on the order of
100 watts
• Integrated device construction
• RoHS compliant
Tyco Electronics Raychem GmbH Finsinger Feld 1 85521 Ottobrunn Germany
Tel: +49 89 6089 386 Fax: +49 89 6089 394
© 2008 Tyco Electronics Corporation • www.tycoelectronics.com
Raychem, PolyZen, TE Logo and Tyco Electronics are trademarks
Benefits
• Stable Zener diode helps shield
downstream electronics from
overvoltage and reverse bias
• Analog nature of trip events minimizes
upstream inductive spikes
• Minimal heat sinking requirements
• Single component placement
• Helps reduce warranty returns &
replacement costs
Applications
• Cell Phones • Printers
• PDAs • Scanners
• MP3 Players • Hard Drives
• DVD Players • Desk Phones
• Digital Cameras • USB Hubs
• Media Players • PBX Phones
• Wireless Base Stations

52
Powering Powering Freight Freight & Transportation
& Transportation
Electric Vehicle Battery
Monitoring
Compact solution for current sensors in
transportation applications
With the higher cost of petrol/gasoline making headline news in recent years, a new urgency has
been placed on alternative methods of propulsion to the traditional combustion engine. Among many
possible alternatives, the battery operated Electric Vehicle (EV) has seen a resurgence of interest and
development.
By Warren Pettigrew, Chief Technical Officer, Raztec Sensors, New Zealand
Two important battery parameters
that are of particular interest to
an Electric Vehicle (EV) operator
are state of charge (SOC), and state of
health (SOH). In order to reliably ascertain
either of these parameters, accurate
current sensing is required over a wide
range of current.
State of Charge
The simple and most common method
of ascertaining SOC is to measure
the battery voltage using a time based
algorithm which takes into consideration
the load condition of the battery.
This method gives reasonably accurate
results under normal operating
conditions. However, if the loading is
particularly heavy (or indeed particularly
light), or if opportunity charging is
incorporated, the accuracy will suffer
substantially. Typically battery charge
gauges indicate a greater capacity than
is available particularly towards the end
of charge or immediately after charging.
The accuracy can be dramatically
improved if current is measured, and
if weighted coulomb counting is performed.
Weighting is necessary to take
into account the reduction of capacity
under heavy loading of the battery.
Coulomb counting is not without its
difficulties as it integrates current with
time – often over long periods. This
means that any offset error is also integrated
which demands that current sensors
must be stable and with minimal
influence from temperature or magnetically
induced hysteresis errors.
State of Health
The battery industry is rapidly coming
to realize that a simple means of
determining the SOH of a battery is to
monitor its float current. As a battery
deteriorates, its float current steadily
increases. One difficulty, however, is obtaining
a suitable current sensor which
will measure from float current levels,
which are fractions of an amp, through
to the many hundreds of possible load
amps. Certain sensors are available, but
their high cost and large physical bulk
make them commercially unattractive.
As a battery ages or deteriorates, then
its float current increases. This increase
in float current can then be used to accurately
predict the remaining life of the
battery.
A common cause of premature battery
failure is from a charger that has a
poor algorithm, or is subject to inappropriate
charging techniques by operators.
Both of these issues are easily detected
if both current and voltage are sensed
with time. These techniques can prevent
expensive premature battery failure
whilst greatly extending battery operating
life. The cost of monitoring is very
quickly recovered from the lower battery
operating cost.
If the monitor includes extended
time logging, warranty disputes can be
quickly resolved and the battery manufactures
will have solid, dependable
data available to close product manufacturing
quality loops.
The relatively small investment in current
sensing as part of battery monitoring
can result in substantial savings in
system operating costs.
Raztec RAZL1500 in EV
applications
The Raztec Link has a performance
that matches or exceeds the very
best open loop current sensors, yet is
extremely compact and economically
priced. EV applications, where high current
measurement, fast response and
more importantly; small physical size,
ease of mounting – both electrically and
physically – galvanic isolation and excellent
signal/noise ratio is required, can include
Electric Cars, Rail Transport, Earth
Moving and Electric Fork-Lift Trucks.
Whilst probably not as high-profile as,
Power Systems Design October 2008
Figure1. Raztec Link with forklift.
for example, the electric or hybrid car
application, the electric fork-lift truck
demands much the same technology,
but more so in almost every area.
Due to its small physical size and superior
performance in electrically noisy
environments, the RAZL1500 is ideally
suited for mounting in the most convenient
location, irrespective of concerns
regarding traditional current shunts such
as physical size, generated heat, electrical
noise etc . . .
Traditionally, current sensing in
EV’s has comprised of current shunts.
Whilst this technology has proven to be
satisfactory in the past, it has certain
limitations and side-effects that make it
far less attractive for use in modern EV
designs. Firstly, its large physical size
www.powersystemsdesign.com
Powering Freight & Transportation
makes demands on the ever decreasing
hardware real estate, the heat generated
during measurement, common-mode
voltage issues and in particular, the very
small signal at low current compared
to the general level of electrical noise.
The figures contained in table1 serve to
highlight these shortcomings.
Physically, the Raztec Link current
sensor looks rather like a fuse or even
a very small shunt but offers some very
significant technical advantages over
shunts when it comes to measuring current.
• Galvanic isolation between the
measured current and the output up to
3000V.
• Negligible power loss
• 4500mV differential output voltage
(no signal amplification required)
• Superior signal-to-noise ratio
• Small physical size
Retained features:
• Excellent frequency response to
350KHz
• Excellent linearity
• Very low drift of null output voltage
• Competitive cost
• Excellent immunity to stray electric
and magnetic fields.
• 5V operation
The key to accuracy is linearity of
response. Linearity can be measured by
deviation from an ideal linear response,
normally expressed as a percentage of
full scale. Full scale requires specifying,
as saturation is inevitable. The 1500A
link has better than 1% linearity over
+/-1000A.
Open-loop sensors are vulnerable to
drifts of transfer function with temperature.
Raztec link sensors are configured
to assure negligible negative drift with
increasing temperature. With most current
control circuits it is advisable that
the output indicates high with increasing
temperature, thus improving safety
and reliability. Typical drift for the Link is

54
Figure 2. Raztec Link schematic.
Powering Freight & Transportation
ing is employed to reduce the possible
effects of noise from high voltage
switching transients and nearby current
carrying conductors.
Noise on the primary voltage can be
capacitively coupled through to the sensor
output – normally as spikes which
can be significantly large. The coupling
effect can be mitigated by providing
electrostatic screening between the
primary voltage and the magnetic field
sensors. Sensor installers must also
ensure that screened output cables
are routed away from noisy potentials.
Another technique to avoid noise effects
when sensing via an Analog to Digital
converter to a microcomputer is to not
attempt to measure the current during
current switching thus avoiding the
noise spike. The Link superimposes a
voltage less than 1V for a primary transient
of 108V/s.
The Link uses Hall sensors that have
an insignificant noise output compared
with useful output voltages.
The use of two Hall elements also provides
an output signal with significantly
improved temperature stability.
Summary
As is so often the case, ‘one size does
NOT suit all’. What the author is attempting
to highlight in this article is that
there is often more than one solution to
a given application need, particularly in
current measurement. Where physical
size and power consumption/thermal
performance is considered not to be
particularly high on the design list of
criteria, then traditional current-shunts
may well fit the bill.
However, with modern Electric Vehicles
where battery life and predictability
of charge are paramount, a current
sensor that enables the design engineer
to accurately determine both SOC and
SOH of the traction battery results in
higher performance, greater productivity,
extended battery life and reduced
running and maintenance costs on the
part of the operator.
electronica: Hall A2, Stand 544
www.raztec.co.nz
Power Systems Design October 2008
www.powersystemsdesign.com
Powering Freight & Transportation
Circuit Protection for
Safer Automotive Electrical
Architectures
Added protection is vital for bus and truck
wire harnesses
The wiring-harness architecture found in trucks, buses and other vehicles with electrical systems based
on 24V technology continues to move forward as more electrical and electronic content is required. It
is not just the conventional functions such as heating, air conditioning and ventilation that now require
electronic control, but the many new systems being introduced within the cab such as GPS (global
positioning systems), sound and communication systems which are adding to the electrical load.
By Guillemette Paour, Automotive Marketing Manager for Raychem Circuit Protection Products,
Tyco Electronics
There is a common misconception
amongst consumers that fuses are
only there to protect them from injury
from devices that have developed a
fault. Due to their historical Amp rating (3,
5, 13A) they are often seen as particularly
essential for home appliances that
require greater power, such as kettles,
toasters or ovens, as opposed to cars,
buses, lorries and larger appliances or
white goods. This is understandable to
an extent. It would seem reasonable
to view the fuse as the ‘weakest link’,
something that will stand between an
electrical supply and someone suffering
serious injury from a shock in the event
of an appliance developing a fault.
Within the engineering community,
there is no such misconception. It is understood
that fuses are used to protect
the wire or cable supplying the power
to it and as a result the equipment
and user. The fuse is the safety valve
against the appliance being powered,
if it has developed a fault. Without a
fuse the power would continue to flow,
which would ultimately result in the wire
overheating and possibly igniting. This
scenario is still the cause of many house
fires and increasingly the cause of the
smouldering cars that are seen at the
roadside.
Some might say this is a subtle difference
and is not relevant, but it becomes
more applicable in environments where
the density of wires carrying power is
rapidly increasing. Today, one of the
densest environments for power carrying
cables is in vehicles, where manufacturers
are under constant pressure
to continue adding new features. This is
not just applicable to cars. The wiringharness
architecture found in trucks,
buses and other vehicles with electrical
systems based on 24V technology has
also undergone considerable change
as electrical and electronic content has
increased. Conventional functions, such
as the HVAC (heating, ventilating & air
conditioning) system, continue to be
converted to electronic control while
many new features, such as GPS (global
positioning systems) and entertainment
systems, are being added to the electrical
load.
The power hierarchy used within vehicles
is typically distributed. Each device
that requires power receives it as a spur
from a larger supply – typically using
larger cables. This hierarchy architecture
minimises the amount of high power
cable needed, which clearly represents
both increased cost and weight. However,
for every added powered device
there is a need to supply power to it.
This forces compromises in the ideal hierarchical
or ‘tree’ wiring structure with
main power trunks dividing into smaller
and smaller branches using overcurrent
protection at each node.
So, in addition to delivering the power,
there is the added need to protect the
cable or wire that carries it. Because a
hierarchal architecture can use smaller
wires and relays on its “smaller branches.”
The resulting harness is smaller
and lighter, providing cost savings, both
in materials and fuel consumption. In
addition, a distributed architecture can
provide system protection together
with fault isolation, which can reduce
warranty costs and increase customer
satisfaction.
The space restrictions within
today’s vehicles impose compromises.
55

56
As each device is added, it is necessary
to also consider the impact it will have
on the wiring harness. Not only that, but
in order to provide adequate protection
for the harness it is also necessary to
consider how that protection – against
overloads or short circuits – will be
added, and where.
Figure 1: Tyco’s Polymeric Positive
Temperature Coefficient (PPTC) devices.
Traditional fuses are designed to be
replaced following a fault, so it is essential
that they are located in an accessible
area to a user or service engineer. That
may not necessarily be close to the actual
device being powered. For instance,
in the case of an electrically adjustable
seat, the motors will be positioned
beneath the seat in an area not easily
accessible. Without careful design,
replacing a fuse could involve removing
the seat, adding significant cost to the
repair. Locating fuses in user-accessible
areas has consequences. If the device
Powering Freight & Transportation
being powered is not located near an
access point, it becomes necessary to
route the wiring harness much further
- between the device being powered,
to the fuse and back again, perhaps
doubling the length of wire needed but,
more significantly, doubling the voltage
drop across the total length of wire.
Power demands and, inextricably,
voltage drops within the automotive environment
are leading to manufacturers
looking at increasing the voltage level
used within the car. Currently, 12V is
standard for passenger cars and 24V for
trucks and buses. These battery voltage
levels are likely to increase to 42V in the
future, to accommodate a greater number
of electrical devices and the power
they require while downsizing the wires.
Fuel economy and reduced emissions
are two of the multiple reasons for the
change.
The heavy-duty vehicle 24V systems,
like the 12V must incorporate protection.
With higher levels of voltage it
becomes necessary to provide higher
levels of protection, which can lead
to the use of larger, heavier and more
expensive solutions.
As shown in Figure 1, there is now an
alternative available to conventional protection
systems, which provides greater
access to localised protection. It comes
in the form of polymeric positive temperature
coefficient (PPTC) devices. These
components are typically smaller than
conventional protection schemes and use
a technology that offers greater flexibility,
both in their positioning and their use.
Figure 2: PPTC devices provide flexibility to the location of the fuse.
A PPTC device can be used multiple
times. Key to its operation lies in the
name, positive temperature coefficient.
The more current the device sees, the
hotter it gets and the higher its resistivity
becomes. As a result, it lets progressively
less current pass, protecting the
wiring harness. The added benefit of the
PPTC device over a traditional fuse is
that once the power is cycled and the
device cools down it resets and is able
to function again. That means once the
fault has been resolved, the device is
ready to start passing a current again
without needing to be replaced. As
shown in Figure 2, this brings in a great
deal of flexibility, with respect to where
the fuse can be placed and the wiring
harnesses it can protect.
The technology that has been used
extensively in the automotive world was
limited to use inside the cockpit for 24V
systems. However, recent developments
have led to the development of the new
range of PolySwitch AHEF devices from
Tyco Electronics.
Developed to operate in harsh conditions
while delivering the necessary
performance, the AHEF devices are
available with current ratings from 0.5A
to 10A and are rated to operate across a
temperature range of -40°C to +125°C.
This permits their use in both passenger
and engine compartments. These devices
give designers the ability to locate
junction boxes close to their intended
electronics, whether in the passenger
compartment to help protect BCUs
(Body Control Units) or in the engine
compartment to help protect HVAC controls
for instance.
The development of these 32V
rated through-hole PPTC devices has
allowed for more scope in the design
of the wiring harness, enabling it to
be optimised for the devices being
powered. By providing resettable
protection, placement is available in
inaccessible locations, such as under
the seat, over the driver console or in
door panels thereby enabling design
engineers to get the power to where
it is needed.
www.circuitprotection.com
Power Systems Design October 2008

58
Powering Powering Freight Freight & Transportation
& Transportation
One Step Closer to
the Birds
Glider uses Vicor battery-controlled electrical
propulsion to take to the air
Gliding is one of the most exhilarating sports in the world. It offers a direct experience of air, wind and
weather in a seemingly limitless space, and comes closest to man’s vision of the freedom of a bird’s
flight. Crucial to this type of flying is the need to gain height in order to reach a thermal. Traditionally, a
winch or a tow plane is used to pull the glider to sufficient altitude so that the fun of gliding in search of
a thermal can begin. The requirement to return to the home airfield without additional support limited the
use of gliders, and made careful flight planning a necessity.
By Marco Panizza, European Applications Engineer, Vicor Europe, Germany
Auxiliary propulsion systems
brought an increase in range and
flexibility, and made it possible
to start gliders without additional towing
tools. A conventional solution was
using combustion motors. However, the
performance of a combustion motor de-
creases with its operating altitude. Combustion-powered
propulsion systems
must be oversized in order to deliver the
desired power at all operating altitudes,
and impose an important weight and
noise burden on the glider. Additionally
combustion engines generate substan-
Figure 1: The Antares 20E glider in climb. The aircraft is driven by a propeller powered
by an electric motor on a hinged carrier beam.
tial heat, and must be allowed to cool
down before being retracted into the
fuselage.
The design team at Lange Flugzeugbau
in Zweibruecken, Germany wanted
to set pilots free by adding an electric
engine for self-powered takeoff
and climbing. The company
used Vicor modules to design
the Antares 20E, the first glider
to receive the prestigious EASA
(European Aviation Safety
Agency) type certification for
an electrical propulsion system,
and one of only three electrically
powered gliders on the market.
The glider’s easy to use retractable
electric propulsion solution
is more reliable, quieter, and
produces less vibration than
traditional combustion engines.
Offering high performance
independent of operating altitude,
electric motors provide
the safest and most convenient
choice for power. By integrating
the entire battery charging
circuitry inside the plane, Lange
produced a completely self-reliant
electrically-powered glider
that can make long-distance
Power Systems Design October 2008
flights, and be recharged at any airfield.
The need for good aerodynamic
performance, however, imposes strict
limits on the weight of the entire system,
particularly that of batteries and charging
circuitry.
Design challenges
One of the challenges in the design
of the glider was the integration of the
battery charging subsystem. The entire
system had to be self-reliant in order to
enable long-distance multi-lap flights
without the need for an external charging
unit at the airfield. The propulsion
motor has a nominal power of 42kW
and operates on a voltage of 288V. The
battery system has to provide enough
power for five minutes of operation or
about 3000m of climbing altitude, which
translates into an overall battery capacity
of 11kWh. Charging has to use a
normal single-phase mains connection,
and a full charging cycle needs to be
completed overnight.
The glider uses Li-Ion battery cells
which require tightly controlled operating
conditions to deliver a consistent,
reliable power output. In order to offer
maximum capacity, the cells must be
operated between 20 and 40°C, so
temperature sensing and cell heating
had to be implemented. Additionally all
cells must be kept on the same charging
state, requiring cell voltage monitoring
circuitry to ensure that all cells
have identical cell voltages. Before any
charge cycle, all cells are discharged to
have the same cell voltage with a tolerance
of only ±20mV ensuring that all
cells will be charged evenly. In practice,
charging is several activities that must
be performed in sequence:
• Cell voltage monitoring and selective
discharging until all cells have the same
voltage within the specified tolerance
• Cell heating until the desired operating
temperature is reached
• Battery array charging until the total
voltage reaches 288V
In addition, the charging electronics
have to fit into the overall system of the
glider. This means that the circuitry has
to meet rigorous, weight, heat management
and size specifications.
www.powersystemsdesign.com
Powering Freight & Transportation
Choosing a charging
module vendor
Since total glider weight has a direct
impact on its flying performance, all
components in the aircraft had to be optimized
for lowest possible weight. Commercially
available chargers that met the
specifications would weigh about 10kg
including mains front-end and cabling –
much too heavy for integration in a glider
with a maximum total takeoff weight of
660kg. As Lange’s design engineers
could not find ready-made charging
units that met the weight requirements,
a new charging subsystem had to be
developed.
The charging subsystem essentially
consists of a mains front-end and a high
voltage, high-power DC-DC converter
with programmable output voltage.
Due to space and weight limitations,
the circuits had to offer high efficiency,
as a major factor in the overall weight
Figure 2: Charging system block diagram. The front-end and the power section
are housed in two separate cabinets and are mounted in the glider’s fuselage.
The front-end consists of the EN1C21 Vicor modules while the power section
comprises Vicor Module V300B48T250BL Vicor DC-DC converters. The power
section is connected to the battery array, which is installed inside the wings.
59

60
of the system would be whether bulky
heat sinks were needed for thermal
management. The weight, efficiency
and controllability specifications called
for the use of semi-customized circuit
modules, and Vicor was the only manufacturer
that could deliver modules that
were both sufficiently light-weight and
still met the efficiency, controllability and
volume specifications.
Implementation with a focus
on weight and efficiency
The charging subsystem is operated
by a dedicated controller, which
communicates with the glider’s system
computer via CAN bus. The charging
cycle is only activated after completion
of the other steps described
above. For space, weight and thermal
management reasons, the subsystem
is divided into two sections, the auto
ranging mains front-end and the power
section which contains the DC-DC
converters.
During a charging cycle, only the
power section generates substantial
heat. The glider electronics contain
www.heatmanagement.com
Powering Freight & Transportation
POWERCLIPS ® Integrated
Heat Management Solutions
for semiconductor
mounting More than 35
standard types available from
stock for all kinds of transistor
packages Samples available
free of charge.
Kunze Folien GmbH · P.O.Box 1562 · 82036 Oberhaching · Germany
Phone +49 (0)89 66 66 82-0 · Fax +49 (0)89 66 66 82-10 · sales@heatmanagement.com
Figure 3: Featuring high efficiency and low weight, the Vicor V300B48T250BL
DC-DC converters are the heart of the charging system.
another element that generates substantial
heat during powered flight: the
motor control circuitry. Since motor and
charging electronics are never used at
the same time, the power section and
the motor control circuitry can share the
same heat sink, reducing weight. The
Vicor DC-DC converter modules contain
a metal base plate which serves both
to mount the module and to establish a
thermally conductive contact to a heat
sink, yielding a very compact, lightweight
design.
The battery
array consists
of 72 highperformance
Li-
Ion cells which
are connected
in series. The
batteries operate
with cell
voltages of
2.7V (‘empty’)
to 4.0V (‘full’),
so that the
circuitry has to
deliver a charge
voltage ranging
from 194V
to 288V, which
is determined
using a cell voltagemeasurement
which is
performed by
the charge controller
at regular
intervals. The
charge controller
derives a
trim voltage
from this mea-
surement and delivers it to the DC-DCconverters
so that the charge voltage
is updated in relation to the batteries’
status. The controller also limits the trim
voltage so that the converters cannot
deliver a higher voltage than 290V, thus
protecting the battery array against
overcharging. As it is only used on the
ground and not during flight operation
Lange did not need to implement any
redundancy in the charging system.
Due to the efficiency and light-weight
design of the deployed Vicor circuit
modules, the resulting charging unit only
weighs 6kg including cabling, freeing
more weight for valuable payload. The
unit consumes approximately 1.7kW
of mains power, and requires just nine
hours to fully recharge the glider’s batteries.
The auto ranging mains frontend
of the charger is compatible to mains
voltages from 110 to 230VAC, and is
thus usable world-wide.
Conclusion
The Antares glider’s self-contained
electrical drive system has moved
man’s flight one step closer to the
elegance and freedom of the birds. The
outstanding electrical power to weight
ratio and high efficiency of the Vicor
solution allowed the design team to
integrate the battery charging system
within the plane without compromising
the flight performance – something that
is crucial to the fascination and thrill of
glider flight.
electronica B2.311 & A5.313
www.vicoreurope.com
Power Systems Design October 2008
Powering Powering Freight Freight & Transportation
& Transportation
Progressing Freight and
Ultracapacitors in energy saving applications
A growing number of energy experts worry about the world's lack of preparation for “peak oil,”
a term referencing the point at which the amount of petroleum that is economically feasible to extract
and refine goes into decline. Peak oil does not mean running out of oil, but rather signifies the end
www.powersystemsdesign.com
of the cheap-fuel era.
By Sven Baechtiger, Key Account Manager, Heavy Transportation, Maxwell Technologies
Oil prices have plunged approximately
30% since surging to a
record $147.27 a barrel in July of
2008. Does this indicate that the crisis
is over? The US per capita oil consumption
is 25 barrels annually. Additionally,
both China and India are consuming
below 2 barrels for the collective population
of 2.5 billion citizens in these locations
and there is an expectation that oil
demand will increase in each of these
countries as more of their citizens look
to enjoy the fruits of the energy-hungry
world.
Maxwell Technologies believes industry
needs to alter its mindset in terms
of energy consumption and energy
management. The time when energy
was wasted without concern in braking
resistors, un-adapted diesel engines,
and in un-recovered kinetic energy, has
now gone.
Energy Storage Efficiency in
Transportation
Hybrid electric busses and cars are
today a familiar concept and can frequently
be seen in many of the
world’s cities. The use of an energy
storage device allows efficient startstop
operation as well as the recovery
of braking energy with fuel consumption
and CO 2 emissions significantly
reduced. These very same principles
are also applicable to heavier vehicles
in public transportation, such as trains,
Transportation
Figure 1. Wide temperature range and low internal resistance of Ultracapacitors outperform
Batteries.
61

62
Powering Freight & Transportation
Figure 2. Maxwell’s BOOSTCAP ® HTM125 module.
trams and metros, all of which benefit
from the adoption of a hybrid power
train approach. Consequently, primary
energy demand and maintenance costs
can be considerably reduced.
The obvious energy storage device
might be a rechargeable battery. However,
such technology shows evidence
of some serious limitations in freight and
transportation applications. Batteries
are heavy in weight, large in size, slow in
charging rate and high in maintenance
costs due to reduced cyclic capabilities.
Furthermore, battery technology suffers
from degraded performance at low temperatures.
Today, heavy transportation application
engineers are considering alternative
energy storage technology - the ultracapacitor.
Ultracapacitors, or doublelayer
capacitors, provide high charge
acceptance, high-efficiency, high cycling
stability, and excellent low-temperature
performance.
Ultracapacitors are therefore the
perfect component to store the heavy
transportation vehicle’s kinetic energy
during frequent braking events. In comparison
to battery chemical reaction,
energy storage in ultracapacitors is
based on an electrostatic reaction with
an extremely short time constant. For
an ultracapacitor, the energy storage
begins as soon as electrons are available.
During the acceleration phase of
the vehicle, the previously stored energy
can be re-injected into the application
thereby avoiding important absorp-
tion in network primary energy. Due to
the extremely low internal resistance of
ultracapacitors, the losses are reduced
to a minimum and the energy transfer
efficiency is maximized. Furthermore,
ultracapacitors can be cycled more
than 1 million times without experiencing
substantial performance degradation.
Additionally, ultracapacitors are
environmentally friendly because they
do not contain heavy metals and can
therefore be recycled easily. Finally, and
perhaps most importantly, ultracapacitors
offer more than 10 times the power
of batteries, which, when translated into
functional application characteristics,
Figure 3. Bombardier’s Mitrac Energy Saver trains use Ultracapacitor technology
for energy storage.
Power Systems Design October 2008
www.powersystemsdesign.com
Powering Freight & Transportation
Figure 4. Still’s Hybrid forklift equipped with Maxwell’s Ultracapacitors modules.
provides higher performance in terms
of acceleration of a vehicle, an essential
goal of such applications.
Ultracapacitors for Heavy Transportation
Applications
Heavy transportation vehicles, such as
trains trams and metros, place particular
demands on energy storage devices.
Such devices must be very robust and
reliable displaying both long operational
lifetimes and low maintenance requirements.
Further, the devices must operate
efficiently under harsh conditions
including handling high peak currents,
high duty cycle and frequent deep discharging.
Maxwell Technologies, has
addressed these issues with its BOOST-
CAP ® HTM125 module for ultracapacitor-based
braking energy recuperation
and torque assist systems in transportation
applications. Operating at 125V, the
new module can store more energy per
unit volume, deliver more power per unit
volume and weight and perform longer
than any other commercially available
ultracapacitor solution.
The HTM125 module is based on
Maxwell’s MC power cell, rated at 3000
Farads, which individually has a very low
internal resistance, resulting in excellent
efficiency during charging and discharging.
Up to 12 modules may be linked in
series to deliver as much as 1500V per
system. One key factor in the energy
storage systems is the thermal management.
Using Maxwell's ultracapacitor
modules, which incorporate efficient
cooling systems, allows higher continuous
currents up to 150A, and 750A as
a peak (750A during 1 second @ 10%
duty cycle), without compromising the
reliability.
Ultracapacitor products have been
fully tested and qualified in light rail
applications over many years. As an
example, Bombardier's LRV (Light Rail
Vehicle) prototype has been in passenger
operation since 2003 in Germany
and has recorded energy savings up to
30% at around 300,000 load cycles per
year. This success has now resulted in
Bombardier delivering Mitrac Energy
Saver trains utilizing ultracapacitor technology
for energy storage for operation
in the city of Heidelberg.
Ultracapacitors for Heavy-Duty
Equipment
In the lifting, hoisting, and excavating
equipment markets, typical characteristics
of the energy storage demands
include deep discharge cycling coupled
with high duty cycle requirements.
Cost is also a significant factor
in the implementation of
an energy storage option. In
heavy duty equipments, the
cost of the unit is outweighed
by the durability, reliability and
productivity factors. The initial
cost of equipment is extremely
high and this means that an
elevated initial investment cost
is returned faster for a higher
performance, reliable and durable
system.
Maxwell’s heavy duty
equipment solutions are the
most flexible energy storage
solution to power cranes,
straddle-carriers, RTG, stackers,
forklift, utility trucks, and
other earth moving and mining
equipments. With the help of
the company’s ultracapacitor
products, harbor crane
manufacturers are providing
innovative solutions to port
authorities delivering savings
of up to 30% on diesel consumption
realized through both braking energy
recovery and downsizing of diesel
engines. The substantial reduction in
terms of CO 2 emissions is also a significant
advantage for the harbor's authorities
in today’s climate where global
warming and levels of gas emissions
are becoming an increasingly greater
concern.
In lifting applications, studies have
shown that new generations of forklifts
equipped with Maxwell's ultracapacitor
products can increase the autonomy
and life of the equipment’s battery system
by more than 25%, thereby reducing
the cost of downtime and maintenance.
The time for efficient and environmentally
friendly energy storage and management
has come and Maxwell’s
ultracapacitor solutions have proven
themselves to fulfil this requirement.
These solutions are an essential part
in today’s innovative, efficient hybrid
system for public transportation and
heavy industrial applications allowing an
increase in power efficiency and a reduction
in fuel consumption and global
CO2 emissions.
www.maxwell.com
63

NEW PRODUCTS NEW PRODUCTS
Compact Buck-Boost Regulators wth Ultra-Fast Switching
Analog Devices has introduced one
of the industry’s smallest buck-boost
regulators—and the first to support
switching frequencies at speeds up to
2.5 MHz. Designed to regulate voltages
above and below the battery output
voltage in portable electronics, ADI’s
ADP2503 and ADP2504 step-up/stepdown
dc-to-dc regulators incorporate
a patent-pending architecture that
delivers seamless mode transitions. The
ultra-fast switching speed of the new
regulators allows designers to use lowcost
multilayer inductors that are half
the size of other solutions. In addition,
the total external component count has
been reduced to three, resulting in a
total PCB area of less than 13mm 2 and
a height of less than 1mm, making the
solution ideal for space-constrained
applications such as wireless handsets,
digital still cameras, portable audio
players and USB-powered consumer
and industrial devices.
“Many lithium-battery-powered
devices require voltage rails in the
2.8-V to 3.6-V range for RF, audio, or
motor applications. The ADP2503 and
ADP2504 are ideal regulators to provide
these voltages when board area and
efficiency are important,” said Arcadio
Leon, marketing director for portable
power products, Analog Devices.
The ADP2503 and ADP2504
regulators are based on ADI’s new
proprietary current-mode buck-boost
architecture, achieving glitchless mode
transitions and outstanding transient
performance across line and load. This
high level of output stability is critical for
powering sensitive analog and digital
circuitry. The devices also feature one of
the industry’s lowest no-load quiescent
current (Iq) levels - 38 µA in power-save
mode - which extends stand-by time in
portable electronics and/or increases
the power budget for the inclusion of
additional features. The proprietary
H-Bridge buck-boost architecture
improves the efficiency by more than
10 percent versus legacy cascaded
boost-buck architectures by reducing
switching losses.
The ADP2503 and ADP2504 operate
at input voltages ranging from 2.3V and
5.5V, which meets the requirements for
single Li-Ion, Li-Ion polymer cell and
multiple alkaline/NiMH cell applications.
Fixed output voltages range from 2.8V
to 5V.
ADP2503 and ADP2504 are available
now in sample quantities and come
housed in a 10-lead 3-mm x 3-mm
thin LFCSP package. The buck-boost
regulators are priced at $1.40 per unit in
1,000-unit quantities.
electronica: Hall A4 Stand 159
Step-Down Converter Draws Only 75uA Quiescent -
Withstands 62V Transients
33VIN, 62V Transient Protection Buck
Regulator
Linear Technology Corporation
announces the LT3972, a 3.5A,
33VIN step-down switching regulator
with Burst Mode ® operation to keep
quiescent current under 75uA. The
LT3972 operates within a VIN range of
3.6V to 33V, with overvoltage lockout
protection against transients as high
as 62V, making it ideal for load dump
and cold-crank conditions commonly
found in automotive applications. Its
internal 4.6A switch can deliver up to
3.5A of continuous output current at
voltages as low as 0.79V. Its Burst Mode
operation provides ultra-low quiescent
current, well suited for applications
such as automotive or telecom systems,
which have always-on circuits and
need to optimize battery life. Switching
frequency is user programmable
from 200kHz to 2.4MHz, enabling
the designer to maximize efficiency
while avoiding critical noise-sensitive
frequency bands. Its 3mm x 3mm
DFN-10 package (or thermally enhanced
MSOP-10E), and high switching
frequency keep external inductors and
capacitors small, providing a compact,
thermally efficient footprint.
The LT3972 utilizes a high efficiency
4.6A, 95mOhm switch, with the
necessary boost diode, oscillator,
control and logic circuitry integrated into
a single chip. Low ripple Burst Mode
operation maintains high efficiency
at low output currents while keeping
www.analog.com
output ripple below 15mVPK-PK. Special
design techniques used in the
LT3972 enable high efficiency over
a wide input voltage range, and the
device’s current mode topology enables
fast transient response and excellent
loop stability. Other features include
external synchronization (from 250kHz
to 2MHz), a power good flag and softstart
capability.
Pricing for the LT3972EDD and
LT3972EMSE starts at $4.25 and $4.35
each, respectively for 1,000-piece
quantities. The LT3972IDD and
LT3972IMSE are guaranteed to operate
from a -40°C to 125°C operating
junction temperature, priced at $5.10
and $5.22 each, respectively in
1,000-piece quantities. All versions are
available from stock.
electronica: Hall A4 Stand 538
Hall A5 Stand 568
www.linear.com
New Surface mount & radial leaded inductors reduce EMI
Murata Power Solutions has
enhanced its radial lead and toroidal
surface-mount inductor portfolios
with the addition of four new ranges
of RoHS compliant components. The
introductions comprise over 50 new part
numbers that reinforce Murata Power
Solutions’ reputation as a provider of
industry-leading magnetic products.
The 1500 and 1900R series are
general purpose radial leaded inductors
suitable for providing filtering in low
to medium current applications such
as those found in power supplies.
The 4200 and 4300 series of toroidal
surface-mount inductors meanwhile are
designed for use in switching AC/DC
power supplies and DC/DC converters.
Their low-profile design makes
them ideal for use in designs where
component height is restricted.
Both the 1500 and 1900R series offer
low DC resistance. The 1500 series is
available with current ratings up to 16.2A
IDC and inductance values that range
from 1.0µH to 1.0mH. The 1900R series
is rated to 7.8A IDC with inductance
values of between 4.7µH and 100mH.
Custom parts are available on request.
Both ranges are supplied in cartons
of 40, are fully compatible with RoHS
soldering systems and have backward
compatibility to Sn/Pb solder processes.
Operating free air temperature range is
-40ºC to +85ºC.
xprinc th driv
automotiv.tlmatics.snsors.infotainmnt.scurity.
The 4200 and 4300 series toroidal
surface-mount inductors have
compact overall dimensions with a
maximum overall height of less than
10mm. Both ranges utilise UL94 V-0
package materials, are pick & place
compatible and meet J-STD-020C
reflow requirements with backward
compatibility to Sn/Pb soldering
systems. The toroidal construction of
the new inductors aids design engineers
by helping minimize EMI issues. The
4200 series has a current rating of up to
15.4A IDC and a choice of inductance
values between 1.27µH and 17.6µH.
The 4300 series comprises parts with
inductance values ranging from 2.1µH
to 4.0µH and a maximum current rating
of 22.4A IDC. Operating temperature for
both ranges is -40ºC to +125ºC.
electronica: Hall B2 Stand 431
www.murata-ps.com
64 Power Systems Design October 2008
www.powersystemsdesign.com
65

NEW PRODUCTS NEW PRODUCTS
MOSFETs for Efficiency, Reliability, and Safety in
Lighting and SMPS
STMicroelectronics has increased the
ruggedness, switching performance and
efficiency of power MOSFETs for lighting
ballasts, where they are used in the PFC
and Half Bridge sections, as well as in
switching power supplies. The use of
innovative SuperMESH3 TM technology
with lower on-resistance guarantees
that higher efficiency is obtained.
Additionally, due to their superior dv/dt
performance and higher breakdownvoltage
margin, these new devices will
provide enhanced reliability and safety.
The first SuperMESH3 devices
introduced are the 620V STx6N62K3,
which will be followed by the
STx3N62K3, also at 620V, as well as
the 525V STx7N52K3 and STx6N52K3.
The savings in on-resistance enabled
by SuperMESH3 reduce R DS(on) in
DPAK packages to 1.28 Ohms in the
STD6N62K3 at 620V and 0.98 Ohms
in the STD7N52K3 at 525V boosting
operating efficiency in applications
such as low-energy lamp ballasts. The
new technology also reduces reverserecovery
time (Trr), gate charge, and
intrinsic capacitance, leading to
improved switching performance and
enabling higher operating frequencies.
As a further advantage of
ST’s SuperMESH3 technology, which
combines strip topology with an
optimized vertical structure, the new
devices also exhibit one of the best-inclass
dv/dt behaviors. This translates
into increased reliability and safety in
lighting and other consumer electrical
applications. All SuperMESH3 devices
are 100% avalanche tested, and also
incorporate zener protection to deliver
all-round robust performance.
By achieving the lowest on-resistance
per area among comparable highvoltage,
fast-recovery technologies,
SuperMESH3 allows the STx6N62K3,
STx7N52K3, STx3N62K3 and
STx6N52K3 to use smaller packages
such as DPAK, than similarly rated
alternatives. This saves footprint and
board size, yet matches the switching
and thermal performance of physically
larger devices.
The STx6N62K3 is available in
IPAK, DPAK, TO-220, and TO-220FP
packages, priced from $0.62 for 1000
pieces.
The STx3N62K3 at 2.5 Ohms will
be available in IPAK, DPAK, D2PAK,
TO-220 and TO-220FP packages.
The STx7N52K3 at 0.98 Ohms will
be introduced in DPAK, D2PAK,
TO-220, and TO-220FP packages
and the STx6N52K3 at 1.2 Ohms will
be available in DPAK and TO-220FP
packages. These lines will enrich the
620 and 520V portfolio of SuperMESH3
products, which will be in volume
production by Q4 2008.
electronica: Hall A5 Stand 207
Hall A5 Stand 159
www.st.com
Super Junction Power MOSFETs Improve Efficiency and
Switching Speed in Applications to 600V
White Power SMD LEDs utilizing InGaN/TAG on Sapphire
Technology
Vishay Intertechnology has released
the industry’s first high-intensity white
power SMD LEDs in the CLCC-6 and
CLCC-6 flat ceramic packages to offer
InGaN/TAG on sapphire technology for
high optical power from 2240mcd to
5600mcd.
Designed to reduce costs in highvolume
applications, the new VLMW63..
series features the CLCC-6 package and
a low thermal resistance to 50k/W, while
the VLMW64 series in the CLCC-6 flat
package offers a low thermal resistance
of 40k/W and an ultra-low profile of
0.9mm.
With compact footprints of 3.3mm
by 3.4mm, the ceramic packages of
the LEDs allow the additional current
drive for a maximum light output while
maintaining a high service life of up to
50,000 hours, making them ideal light
sources in space-limited applications
where thermal management is a key
consideration.
The devices are optimized for
backlighting and illumination in
automotive and transport, consumer,
and general applications. Typical end
products include flashes for cameras;
emergency lighting; and automotive
instrument panels and exterior lighting,
such as brake lights and turn signals.
The LEDs offer a typical luminous flux
of 11000 mlm and optical efficiency
up to 30 lm/W. The devices feature a
luminous intensity ratio per package unit
of IV max/IV min ≤1.6, forward voltage
up to 4.3V and 60° half-intensity angle.
The VLMW63 and VLMW64 LEDs
are compatible with IR-reflow solder
processes, in accordance with CECC
00802 and J-STD-020C. Preconditioned
according to JEDEC Level 4 standards,
the CLCC-6 and CLCC-6 flat packages
are lead (Pb)-free and RoHS-compliant.
The devices are automotive qualified
AEC-Q101 and offer an ESD-withstand
voltage up to 2kV in accordance with
JESD22-A114-B.
Samples and production quantities of
the new VLMW63 and VLMW64 highintensity
white power SMD LEDs are
available now.
electronica: Hall A5 Stand 143
www.vishay.com
Featuring 20A (TK20A60U), 15A
(TK15A60U) and 12A (TK12A60U)
current ratings, the three new DTMOS
II power MOSFETs are ideal for switch
The new DTMOS II family brings
together the latest version of
Toshiba’s Super Junction MOSFET
technology with the company’s optimised experience the drive
mode power supplies, lighting ballasts, cell design. The result is a range of
motor drives and other applications
requiring high efficiency, high-speed
devices that combine minimised
on resistance and gate charge – a
automotive.telematics.sensors.infotainment.security.
switching. Respective RDS(on) and Qg key factor in switching speed – with
ratings of 0.19Ω and 27nC, 0.3Ω and high levels of ruggedness. All of the
17nC, and 0.4Ω and 14nC mean that the new MOSFETs, for example, provide
devices have the industry’s lowest ‘Qg * industry-leading avalanche durability
Toshiba Electronics Europe has RDS(on)’ at comparable Current class. and reverse recovery characteristics.
announced the first products from its All of the new devices are supplied in
electronica: Hall A5 Stand 476
new DTMOS II family of rugged, highefficiency,
high-speed power MOSFETs.
the compact TO220SIS ‘smart isolation’
package that offers full pin compatibility
www.toshiba-components.com
The new 600V power MOSFETs
with existing TO-220 devices, while
combine a very low on resistance (RDS(on)) delivering a 13.5% reduction in PCB
and reduced gate charge (Qg) to deliver
an RDS(on) x Qg ‘figure of merit’ that is
15% lower than the company’s existing
DTMOS I range and 68% lower than
conventional MOSFETs.
66
mounting height. This package uses
copper connections rather than
aluminium bonding wires, which leads to
improved current and lower resistance
ratings and aids heat dissipation.
Power Systems Design October 2008
get the whole picture
electronica automotive: a unique industry gathering for leading international manufacturers, prominent experts
and decision-makers in automotive electronics. Special highlight: the electronica automotive conference
(Nov. 10–11, 2008), which focuses on the world’s latest topics and trends and the challenges of the future and
promotes www.powersystemsdesign.com
the transfer of know-how and networking at the highest level. www.electronica.de/automotive.
electronica 2008
automotive
23rd world’s leading trade fair
67
Be sure to visit the concurrent trade fair www.hybridica.de
electronica automotive conference
Strategy + Technology + Networking
www.electronica.de/automotive
New Munich Trade Fair Centre
November 11–14, 2008

68
NEW PRODUCTS
All-in-One Solution for Programmable Motion Control
Crouzet has introduced the Motomate
Brushless Motor featuring compact size,
convenience and easy programmability.
Designed with an integral controller,
the new motor provides an all-inone
solution for a wide range of
applications where programmable
movement of simple mechanisms is
required. Typical uses include control of
automatic doors and door lifts, access
barriers, rolling advertisement boards,
intelligent conveyor systems, robotic
swimming pool cleaners, and machine
subassemblies.
Motomate incorporates a Crouzet
built-in Milleneum2 controller, brushless
motor drive, motor, and gearbox
in a compact 2-1/2” x 6” package.
The brushless motor features a high
motor efficiency of 90% compared to
asynchronous motors of only 40%,
and a surprisingly high starting torque
given its compact size. With the power
electronics incorporated directly inside
the motor, the need for an external
speed controller is eliminated, optimizing
space for tight product designs.
By combining the controller, drive,
motor and gearbox into a single unit, the
Motomate offers complete compatibility
and convenience. “If you buy these four
components separately, you have to get
them to work with each other,” explains
Jim McNamara, Crouzet Application
Engineer. “The Motomate eliminates all
that by providing a small, neat package
where all components are already
integrated and compatible.”
Motomate is available with a motor
range of 30 or 80 Watts in several
configurations to meet all types
of required movement. Motomate
produces up to 0.3N.m in the direct
drive configuration, up to 3.5N.m in
the right angle configuration, and up to
30N.m in the planetary configuration
Rugged & Reliable Automotive-Qualified 600V ICs
International Rectifier has introduced
the AUIRS212xS family of rugged
600V, single channel high-side driver
ICs for low-, mid-, and high-voltage
automotive applications including
general purpose automotive drives,
high-voltage actuators and fuel-efficient
direct injection systems.
Qualified to AEC-Q100 standards,
the AUIRS2123S and AUIRS2124S high
Specifications
speed power MOSFET and IGBT drivers
offer a gate drive supply range from 10V
to 20V. The output drivers feature a highpulse
current buffer stage designed for
minimum driver cross-conduction while
the floating channel can be used to drive
N-channel power MOSFETs or IGBTs in
the high-side configuration operating up
to 600V. Both devices feature negative
voltage spike (Vs) immunity to protect
the system against catastrophic events
during high-current switching and short
circuit conditions.
Designed specifically for automotive
applications, the new ICs use a
proprietary latch immune CMOS
technology featuring exceptional
negative Vs immunity to deliver the
ruggedness and reliability essential for
harsh environments and automotive
(custom torques are also available).
Other important characteristics include
analog output and internal torque
(current) sensing capabilities for
increased application flexibility. Intuitive
programming with graphical function
blocks allow easy programming of
acceleration and deceleration in forward
or backward motion with controlled time
and speed ramps. Reprogramming is
easily accomplished by using a PC or
a removable memory module. Sensors
and actuators can be easily added to
the controller’s inputs/outputs as the
need for expansion is required.
Motomate is designed to provide a
long service life of 20,000 hours and
continual torque force even under
locked rotor conditions (BTN model
only). The unit’s 24 VDC supply voltage
offers added security in case of accident
or vandalism, and a battery supply
option provides standard or backup
energy for on-board systems or critical
medical equipment.
www.crouzet-usa.com
under-the-hood applications.
The AUIRS2123S features output
signals in phase with the input signal
while the AUIRS2124S features output
signals out of phase with the input
signal. Both devices provide undervoltage
lockout and CMOS Schmitttriggered
inputs with pull-down.
The new ICs utilize IR’s advanced
high-voltage IC process which
incorporates next-generation highvoltage
level-shifting and termination
technology to deliver superior electrical
over-stress protection and higher field
reliability.
More information is available at the
International Rectifier website at http://
www.irf.com/whats-new/nr080904.html
Available in an 8-lead SOIC package,
production quantities are available
immediately. The automotive- qualified
devices are lead-free and RoHS
compliant.
electronica: Hall A5 Stand 343
www.irf.com
Power Systems Design October 2008

Texas Instruments
Linear Technology
Fairchild Semiconductor
Magnetics
Microchip Technology
Advertisement
TI’s three new smart battery management
integrated circuits improve measurement and
protection of multi-cell, lithium-based batteries
used in power tools, e-bicycles, and portable
medical and test equipment. The battery
management controller bq78PL114 provides
complete lithium battery system control,
monitoring and safety functions for 4-series cells.
By leveraging the PowerLAN communications
interface, a designer can combine multiple
bq76PL102 dual-cell monitor devices with this
Linear Technology Corporation announces
the LT3080, a 1.1A 3-terminal LDO that may
be easily paralleled for heat spreading and
is adjustable with a single resistor. This new
architecture regulator uses a current reference to
allow sharing between multiple regulators with
a small length of PC trace as ballast, enabling
multi-amp linear regulation in all surface-mount
systems without heat sinks.
The LT3080 achieves high performance
without any compromises. Featuring wide input
Gain a Highly Efficient and Flexible Pointof-Load
Power Conversion Solution with
Fairchild’s Digital Power Controllers
These digital power controllers combine
digital loop control with highly integrated power
management capabilities to offer flexible, easyto-design
power delivery solutions. These
controllers address a wide variety of complex
power system requirements found in applications
Magnetics is pleased to announce the
addition of XFLUX TM , a distributed air gap 6.5%
SiFe material, to our existing powder core line. A
true high temperature material, with no thermal
aging, XFLUX offers lower losses than powder
iron cores and superior DC Bias performance.
XFLUX cores are ideal for low and medium
frequency chokes where inductance at peak
is critical. One of the many challenges facing
designers of high power circuits is maintaining
Microchip Offers Free Field Oriented Control
Algorithm for New Low-Cost Motor Control
Digital Signal Controllers
Microchip announces 10 new 28- and 44-pin
16-bit Digital Signal Controllers (DSCs) for motor
control designs requiring increased memory,
performance, or enhanced peripherals, while
obtaining cost and size savings by using lower
pin-count devices. Additionally, Microchip
controller to create a smart battery solution for
up to 12 rechargeable cells. Another degree of
integration, safety and protection to multi-cell
applications is added with bq77PL900, the new
lithium-based battery protector and analog front
end for 5- to 10-cell battery systems.
See: www.ti.com/bq78pl114 and www.ti.com/
bq77pl900.
Visit Texas Instruments at electronica: hall A4,
booth 420.
voltage capability from 1.2V to 40V, it has a low
dropout voltage of only 300mV at full load. The
output voltage is adjustable, spanning a wide
range from 0V to 40V, and the on-chip trimmed
reference achieves high accuracy of +-1%. The
wide V IN & V OUT capability, tight line and load
regulation, high ripple rejection, low external
parts count and parallel capability make it ideal
for modern multi-rail systems.
www.linear.com
such as datacom equipment, servers, FPGA
power supplies, DDR memory power supplies
and industrial control equipment.
http://www.fairchildsemi.com/products/
digitalpower/index.html
inductance in the power choke at maximum
load. XFLUX is the cost-effective solution to
getting enough inductance in a reasonable size
package.
Seven toroid sizes (60 permeability) are
currently available. Outside diameters range
in size from 21mm to 47mm. New sizes and
permeabilities will be added in the future.
www.mag-inc.com
announced five motor control software solutions
for: Power Factor Correction (PFC), sensorless
Field Oriented Control (FOC) of a PMSM motor,
sensorless FOC of an ACIM motor, sensorless
control of a BLDC motor using Back EMF
filtering and sensorless BLDC control with Back-
EMF Filtering Using a Majority Function.
www.microchip.com/DSCMOTOR
Alpha & Omega Semiconductor ................................................. 6
Analog Devices ......................................................................... 7
Analog Devices ......................................................................... 65
Ansoft ...................................................................................... 13
APEC ........................................................................................ 71
Bergquist ................................................................................. 15
C&K Components .................................................................... 12
Cirrus Logic ............................................................................. 21
Coilcraft ................................................................................... 11
Crouzet ..................................................................................... 64
Digi-Key ..................................................................................... 1
Digi-Key ...................................................................................... 6
electronica .........................................................................65-60
EpowerPack ............................................................................ 43
Ericsson Power Modules ....................................................... 19
Fairchild Semiconductor ........................................................C2
Fairchild Semiconductor ..................................................... 24,37
Gresham Power Electronics ....................................................... 8
International Rectifier ............................................................C4
International Rectifier ............................................................... 16
Intersil ......................................................................................C3
isuppli ....................................................................................... 18
ITWPaktron ............................................................................. 10
Kienbaum ................................................................................ 57
Kunze ....................................................................................... 60
LEM .......................................................................................... 31
Lineage Power .......................................................................... 12
Linear Technology ............................................................... 5,40
Linear Technology ..................................................... 29,46,52,65
Lti REEnergy ............................................................................... 6
www.powersystemsdesign.com
Companies in this Issue
NEW PRODUCTS
Company Page Company Page
Please note: Bold---companies advertising in this issue
Magnetics ................................................................................ 23
Maxwell Technologies ........................................................... 6,61
Maxwell Technologies ............................................................ 27
Micrel ....................................................................................... 25
Microsemi ................................................................................. 12
Murata ...................................................................................... 68
National Semiconductor ........................................................ 17
Ohmite ....................................................................................... 9
On Semiconductor ................................................................... 68
Philips Lumileds ....................................................................... 41
Power Systems Design Worldwide ....................................... 44
PowerPack .............................................................................. 70
Raztec Sensors ........................................................................ 54
Ridley Engineering ....................................................... 32,33,47
Ridley Engineering .................................................................... 20
Sharp Microelectronics Europe ................................................ 28
SMP .......................................................................................... 14
SolFocus .................................................................................... 6
STMicroelectronics ................................................................ 8,66
Texas Instruments .................................................................... 2
Texas Instruments .................................................................... 26
Toshiba Electronics .................................................................. 66
TTI ............................................................................................ 12
Tyco Electronics ..................................................................... 51
Tyco Electronics ....................................................................... 55
Vicor Europe .......................................................................... 6,58
Vicor/Picor ................................................................................ 30
Voltage Multipliers .................................................................. 10
Waseda University ...................................................................... 8
71

72
Whichever Way the Wind Blows…
I’m getting a continuous flow of news
reports, particularly in wind power
with photovoltaic technology on the
increase, as well as the higher efficiency
power devices and modules now constantly
hitting the market. It just shows
the great change we are seeing in the
mindset of the economy. Now, power and
power generation in particular, is getting
the attention it deserves. The ‘penny has
finally dropped’ with the gate keepers
and purse holders, that this really is a
good thing. It also presents an investment
opportunity for those with funds available.
Ericsson has unveiled its latest
energy-optimized radio base station
site concept, a research project for a
pioneering wind-powered Tower Tube,
working with Vertical Wind AB and Uppsala
University in Sweden. It harnesses
wind power via a four-blade turbine with
five-meter blades vertically attached
to the tower. The vertical rotor blades
Belgian offshore wind farm - Thornton
Bank.
Reported by Cliff Keys, Editor-in-Chief, PSDE
work silently and minimize the load on
the tower during operation. Trials will be
conducted to determine if the design
can enable low-cost mobile communication,
with reduced impacts on both
the local and global environment.
Eclipse Energy has promised the
world's “most efficient" wind development,
after gaining permission to build
the UK's first commercial-scale offshore
wind farm to be based on giant 5MW
turbines. The Ormonde Wind Farm in
the Irish Sea will use REpower wind
turbines, as demonstrated at the twoturbine
Beatrice wind farm off the eastern
Scottish coast, with plans to use 30
units to generate a total of 150MW.
The project will also have a platform
hosting three 30MW gas turbines to
feed from the two Ormonde gas fields
underneath - delivering power during
periods of light wind.
REpower has also completed the pilot
phase for Belgian offshore wind farm
Thornton Bank, having now assembled
the rotor for the sixth turbine. The company
C-Power is the contracting party
for the project which is located approximately
30 km from Zeebrugge in a water
depth of some 25 metres. C-Power’s
plan is to develop the Thornton Bank
wind farm to a total of 300 MW.
The Finnish government has agreed
to construct wind power plants over the
next decade. Indications are that the
aim is to generate about 2000 MW of
wind power by the year 2020 requiring
about 1,000 turbines.
The proposal calls for development
of wind parks in key catchment areas
such as coastlines, to accommodate the
large number of turbines needed. The
proposal is part of government's climate
and energy strategy that is currently
under consideration.
It’s very encouraging to see these
projects finally coming to fruition.
www.powersystemsdesign.com/
greenpage.htm
Power Systems Design October 2008

Features
Part Number
V BUS
V S -COM
-V S
Rugged, Reliable
Motor Control - by Design
Single-
Phase
Protect Against Catastrophic Events With IR’s High Voltage ICs
3-Phase
Negative Vs
Immunity
V S Undershoot
Integrated
Bootstrap
Greater
protection
against a
“negative Vs”
event
t t
Advanced
Input Filter
IRS260xD X X X X
IRS2336D X X X X
Current
Sense OPA
IRS233xD X X X X X
Ground Fault
Detection
DC Bus
Sensing
IRS26302D X X X X X X
IRS26310DJ X X X X X
Hall A5,
Stand 560
For more information call +33 (0) 1 64 86 49 53 or +49 (0) 6102 884 311
or visit us at www.irf.com
Brake/PFC
Drive
Designed and characterized to be
tolerant to repetitive negative Vs
transient voltage
Characterized to withstand short
circuit events
Tolerant to large dV/dt
Integrated bootstrap functionality
Advanced input fi lter
Fully operational up to 600 V
THE POWER MANAGEMENT LEADER