Presentation Description: This presentation introduces a novel solution for the transformer-less negative voltage generator of SiC MOSFETs gate drive. In this presentation, the proposed fast negative voltage generation circuit is implemented on a digital controlled SiC based 7.5kW prototype. Compared to the conventional negative voltage generation circuit, it can help to quickly produce the negative gate voltage after the first switching action in a low-cost solution with only Zenner diodes, capacitors and resistors. It can help to ensure the reliability of the SiC MOSFET gate drive in a very compact design, very suitable for switch mode power supply (SMPS) for server and AI power which require high power density and efficiency. Counter measurements were done to generate a+15V and -3V gate voltage, it takes more than 10 switching cycles to drag the negative voltage to only -2.4V and nearly no negative voltage at the beginning cycles in the conventional solution, lead to high risk of short through issue in half-bridge applications. With the proposed solution, only after one switching cycle the negative voltage reaches to -2.94V, enabling the SiC MOSFET to operate more reliably in half-bridge applications.
