A crosstalk suppression technique for SiC MOSFETs in the bridge-leg configuration

Power semiconductor devices made of wide bandgap (WBG) materials, such as SiC and GaN, have higher switching speed compared to their Si counterparts. Fast switching speed brings benefits including low switching loss and high operation frequency. At the same time, the high dv/dt associated with fast switching speed imposes EMI and reliability concerns. One of which is the interaction between the top switch and the bottom switch in a bridge-leg configuration. This interaction, also known as the crosstalk effect, could lead to the false triggering of the devices. The false triggering in a bridge-leg configuration could cause high shoot-through current, unstable oscillation and system failure. In this paper, a crosstalk suppression technique is proposed. The proposed technique could suppress the induced gate voltage caused by high dv/dt and Miller capacitance by injecting a cancellation current. Both positive and negative induced gate voltage can be suppressed with the proposed technique without sacrificing switching speed. Different from existed techniques, the proposed technique requires no additional control strategy and could be integrated inside the power module.