Photonic crystals in biology - NanoTR-VI

Poster Session, Thursday, June 17Theme F686 - N1123Fully Differential High Voltage Amplifier Design for Stick-slip NanopositioningNazmi Burak Budanur 1* , Devrim Yılmaz Aksın 1 , Oğuzhan Gürlü 21 Electronics & Communications Department, Istanbul Technical University, Istanbul 34469, Turkey2 Physics Department, Istanbul Technical University, Istanbul 34469, TurkeyAbstract – A fully differential high voltage amplifier to drive stick-slip piezoelectric actuators is designed. The amplifier consists of a fullydifferential amplifier and a common mode amplifier as ICs, and a power boosting stage with discrete components. By this design approach weachieve slew rates of 300 V/μs on high capacitive loads of 10 nF.The motivation of this work is to build a high resolutionnanopositioner to be used in the sample positioning stage of ascanning tunneling microscope (STM). Due to the stick-slipmotion principle, a high voltage (with an amplitude ofapproximately 300V) ramp signal with very high slew rates isneeded to drive piezoelectric ceramics with several hundredthsof grams of load on them. Period of the ramp signal should bein the range of 0.1s in order to make the motion in reasonabletime scales. Additionally, a high voltage and fast controlelectronic can be applied in other systems that require nanopositioning by means of piezo electric positioners.There are single ended examples of HV amplifiers inliterature with an operational amplifier in the input stagefollowed by class-AB power boosting output stages in whichthe output common mode is determined by a simple negativefeedback [1], [2]. Our design, shown in Figure 1, has threemain blocks: Input fully differential amplifier, class-AB poweramplifier and common mode feedback amplifier. Inputamplifier and the common mode amplifier are designed in0.35 micron CMOS technology with 3.3V sources, and thepower amplifier is build with discrete components with a155V DC source. Since the output common mode level is tobe determined at the half of the high voltage DC source,common mode sensing circuit divides the output voltage to asuitable level.We design and simulate our circuit on Cadence VirtuosoSpectre with SPICE models of discrete components and theAMS 0.35μm libraries. The power stage will be realized withdiscrete components whereas the low power sections will berealized through AMS. AC simulation result of the differentialloop is shown in Figure 2. As it is clear from the figure, theDC gain of the amplifier is 90dB, its gain band width productis 370kHz and its phase margin is 83 degree.Figure 2. AC Simulation result.In conclusion, a fully differential amplifier design with a300V/μs slew rate is done to drive stick-slip piezoelectricnanopositioners. This work is a collaborative project of ITUVLSI and nano scale surface science labs.* budanur@itu.edu.tr[1] Colclough, M. S., 2000, A Fast high-voltageamplifier for driving piezoelectric positioners, Review ofScientific Instruments, vol.71 pp. 4323-4324[2] Wang, D. H., Zhu, W., Yang, Q., Ding, W.M., 2009,A High-voltage and High-power Amplifier for DrivingPiezoelectric Stack Actuators, Journal of Intelligent MaterialSystems and Structures, Vol. 20 pp. 1987-2001Figure 1. HV Amplifier Design BlocksOne of the main advantages of the fully differentialapproach is the ability to use relatively low voltage devices.Since high voltage BJT and MOS transistors have largegeometries, parasitic capacitors of these devices determine thefrequency behavior of the whole circuit. It is possible to obtaina differential voltage on the load, approximately double of theDC source.6th Nanoscience and Nanotechnology Conference, zmir, 2010 662