Quantification of Self-Damping of Power MOSFET in a Synchronous Buck Converter
Ringing in the switching waveform of the switching power supply (e.g., synchronous buck converter) is known to cause broadband electromagnetic interference problems in the 30-300 MHz range. The measured switching waveform shows overshoot and, then, exponential decay of the ringing. It has been observed that this exponential decay rate varies significantly between using different low-side FETs; thus, the low-side FET dominates the attenuation of the ringing. This paper provides a novel method for quantifying the losses by using the measureable quantity "Ross," which is equivalent to the loss of the output capacitance Coss of the FET. This paper describes the method of measuring Ross and explains its relevance to the self-damping of the switch ringing. The method permits selection of a low-side FET to optimize the electromagnetic compatibility performances of the supply.
K. Kam et al., "Quantification of Self-Damping of Power MOSFET in a Synchronous Buck Converter," IEEE Transactions on Electromagnetic Compatibility, vol. 53, no. 4, pp. 1091-1093, Institute of Electrical and Electronics Engineers (IEEE), Nov 2011.
The definitive version is available at https://doi.org/10.1109/TEMC.2011.2157165
Electrical and Computer Engineering
Electromagnetic Compatibility (EMC) Laboratory
Keywords and Phrases
Broadband EMI; Buck Converters; Device Parameters; Exponential Decay Rates; Exponential Decays; Power MOSFET; Self-Damping; Switching Power Supplies; Switching Waveforms; Synchronous Buck Converter; Damping; Decay (Organic); Electric Power Supplies to Apparatus; Electromagnetic Compatibility; Electromagnetic Pulse; Electromagnetic Wave Interference; Electromagnetism; MESFET Devices; Power Electronics; Signal Interference; DC-DC Converters; Buck Converter Electromagnetic Interference (EMI); FET Device Parameter; Switch Ringing
International Standard Serial Number (ISSN)
Article - Journal
© 2011 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.
01 Nov 2011