Optimising snubbers for high-current emitter-switched transistors

The authors analyse a soft voltage-clamp to find a simple design procedure for optimising series-snubber and clamp reset-time circuits for a given voltage rise above the supply-rail. This analysis is applicable to other switches requiring voltage clamping rather than load-line tailoring, including MOSFETs. Their advantages of: reduced power dissipation over shunt-snubbers; current-dependent power dissipation, independent of supply-voltage; and absence of cross-current peaks in phase-legs are likely to promote continued usage