1.11 Driving SiC MOSFETs in auxiliary power supplies
Auxiliary power supplies are commonly found in industrial, grid infrastructure and automotive end equipment like motor drives, PV inverters, e-meters and traction inverters. Auxiliary power supplies are an integral part of the main AC-DC/DC-DC/DC-AC power conversion system in which they are used to power low voltage subsystems such as gate drivers, microcontrollers, fans and sensors, etc. A typical auxiliary power supply is a flyback converter which generates low voltage DC rails from a high voltage DC bus. For DC bus voltage up to 600V, Si MOSFET is the preferred power switch in the flyback converter. But with increasing DC bus voltage requirements (800V EV battery system or 1kV PV power system), SiC MOSFETs are becoming preferred choice due to their better Figure-of-Merit. Numerous PWM controllers are available in the market to drive Si MOSFETs efficiently in auxiliary power supplies. However, since SiC MOSFET gate drive requirements are different from those of a Si MOSFET, existing PWM controllers cannot be directly used to drive SiC MOSFETs.
In this video we will discuss the techniques to drive SiC MOSFETs efficiently and reliably with Texas Instruments General Purpose PWM controllers.