Effect of parasitic elements in a power converter on the switching performance of a MOSFET-snubber-diode configuration

This paper presents a detailed study on the switching process of a MOSFET-snubber-diode (MSD) configuration commonly used in power converters. An analytical model which takes critical parasitic elements and the interactions between gate drive circuit and power circuit into consideration is derived to evaluate the switching characteristics. The influence of parasitic elements and important circuit components in terms of power loss, ringing effect and device stress is discussed under two different conditions for the determination of current slew rate. Based on this work, guidelines are given for the design of high-frequency switching circuits with tradeoff between power loss, oscillation and device stress. The analysis has been successfully verified by the experimental results of a 750W boost converter.