Analysis for crosstalk of SiC-MOSFET in a bridge circuit and its active-clamped driver based suppression methods

Abstract

Because of the benefits of lower on-state resistance, higher operating voltage, and higher switching frequency, SiC-MOSFET has gradually become an ideal choice for the development of power converters operating in high voltage, temperature, and power density. However, the greater dv/dt and di/dt during fast switching transients in the bridge circuit may produce substantial crosstalk problems on the complementary device due to parasitic characteristics of the device itself and its package, and with the lower turn-on threshold voltage and reverse voltage withstand capability, the crosstalk voltage will directly threaten its safe operation. This paper presents the association between the crosstalk voltage and the parameters in driving circuit and device according to the theoretical analysis of the crosstalk mechanism in a half-bridge circuit and based on the analysis, a gate driver circuit using auxiliary low-power Si-MOSFET are proposed to suppress the crosstalk spike without additional negative gate–source voltage or control signal and can be implemented with low cost and less complexity. The operation principle and parameter design of the key components are analyzed later. Finally, the simulation and experiment results show that proposed active clamped gate driver is effective at suppressing crosstalk.

Keywords

• SiC-MOSFET
• Gate driver
• Auxiliary circuit
• Active-clamped
• Crosstalk suppression