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International Journal of Power Management Electronics
Volume 2008 (2008), Article ID 412175, 9 pages
http://dx.doi.org/10.1155/2008/412175
Research Article

Performance Analysis of Trench Power MOSFETs in High-Frequency Synchronous Buck Converter Applications

1School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, P.O. Box 162362, FL 32816, USA
2Freescale Semiconductor, Tempe, AZ, USA
3Cherokee International, Santa Ana, CA, USA
4Intel Corporation, Hillsboro, Oregon, USA

Received 3 January 2008; Accepted 7 March 2008

Academic Editor: Peter Barbosa

Copyright © 2008 Yali Xiong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper investigates the performance perspectives and theoretical limitations of trench power MOSFETs in synchronous rectifier buck converters operating in the MHz frequency range. Several trench MOSFET technologies are studied using a mixed-mode device/circuit modeling approach. Individual power loss contributions from the control and synchronous MOSFETs, and their dependence on switching frequency between 500 kHz and 5 MHz are discussed in detail. It is observed that the conduction loss contribution decreases from 40% to 4% while the switching loss contribution increases from 60% to 96% as the switching frequency increases from 500 KHz to 5 MHz. Beyond 1 MHz frequency there is no obvious benefit to increase the die size of either SyncFET or CtrlFET. The RDS(ON)×QG figure of merit (FOM) still correlates well to the overall converter efficiency in the MHz frequency range. The efficiency of the hard switching buck topology is limited to 80% at 2 MHz and 65% at 5 MHz even with the most advanced trench MOSFET technologies.