A Multi-step Active Gate Driver for Suppressing Crosstalk of SiC MOSFET

Silicon carbide (SiC) MOSFETs are widely used in higher efficiency power electronic converters because of its higher switching speed and lower losses. However, the high switching speed of SiC MOSFET exacerbates the crosstalk in the bridge configuration. In order to suppress crosstalk, a Multi-step active gate driver is proposed by changing the gate-source voltage and capacitance during the switching transients. The negative voltage and capacitor are applied to the gate-source of SiC MOSFET when a positive spike occurs. And zero voltage is applied to the gate-source of SiC MOSFET when a negative spike occurs. Thereby the gate-source voltage is always in the safe region and the switching speed of SiC MOSFET will not be changed. In addition, the mechanism of the proposed active gate driver and operational principles are analyzed. Finally, the effectiveness for suppressing the crosstalk is proved based on the Wolfspeed 1200V SiC MOSFET in the half bridge circuit.