Switching Fast 1200V SiC Cascode with a Snubber

Abstract:
This paper presents the benefits of using snubber with fast switching SiC devices in typical applications based on a half-bridge configuration. A common challenge of using SiC is the fast switching speed of SiC devices imposes excessive voltage stress and ringing to existing designs of Si. Optimization of PCB layout to reduce parasitic inductance can help but may require major re-designs and cause product release delay. Moreover, the common approach to reduce switching speed from the gate drive would increase loss and delay time. A practical solution using snubber with fast switching SiC devices is provided. The solution is verified by experimental results of double pulse test (DPT). The beneficial impact of snubber is analyzed for both hard switching and soft switching applications.