Design and Performance Assessment of a Digital Gate Driving Solution for Silicon Carbide Power Modules

Abstract:
To fully exploit benefits brought by the silicon carbide (SiC) MOSFETs, gate drivers should be designed properly, Recent advancements in SiC MOSFETs have posed various challenges to drive them. Conventional analog gate drivers are where the turn-on and turn-off slopes are defined by a gate resistor and in some cases a gate to source capacitor. However, the rapid switching causes ringing on gatesource voltage Vgs, false fault and drain-to-source voltage Vds overshoot. In this work, the design and performance of the Microchip’s digital gate drivers (DGD) feature augmented switching are presented. This is a technique in which the Vgs is stepped during turn-off. These steps are configurable in voltage and time and take advantage of the MOSFET miller plateau to minimize ringing and overshoot. Extensive experimental results on 1.7 kV SiC modules are presented to highlight the capability of the DGD.