SiC MOSFETs: High−Voltage Switching Power Applications and Gate Drive Optimization

SiC MOSFETs have unique gate drive requirements. In general, they require a 20−V, VDD gate drive during the on−state to provide lowest on−resistance. Compared to their silicon counterparts, they exhibit lower transconductance, higher internal gate resistance and the gate turn−on threshold can be less than 2 V. As a result, the gate must be pulled below ground (typically −5 V) during the off−state. Understanding and optimizing the gate drive circuitry has a profound effect on reliability and the overall switching performance that can be achieved.

This paper highlights the unique device characteristics associated with SiC MOSFETs. Critical design requirements related to optimal gate−drive design for maximizing SiC switching performance will be described. System-level considerations such as start−up, fault protection, and steady-state switching will also be discussed.