Impact of Parameter Spread in Parallel-Operated SiC MOSFETs for Hard-Switching Conversion

Abstract:
This paper examines the impact of parameter spread in parallel-operated SiC MOSFETs during high switching frequency and hard switching operations. Seventy samples of a 1200V 60mOmega rated SiC device in a TO-247 4-pin package were selected for the study. These samples were characterized for screening threshold voltage VGS(th) and transfer characteristics ID(V GS). The study focused on the dynamic performance imbalance caused by unequal current sharing, specifically during the turn-on event. This imbalance in current sharing arising from parameter spread was investigated through a doublepulse test and mathematical modeling of the phenomena. On top, this study provides recommendations for mitigating dynamic current imbalances. Finally, a temperature assessment showing the effects of imbalanced energies in continuous testing for a half-bridge DC-DC conversion is also presented.