A Multilevel Gate Driver of SiC MOSFETs for Mitigating Coupling Noise in Bridge-Leg Converter

Silicon carbide (SiC) devices can significantly increase power efficiency, temperature reliability, power capacity, and power density because of their outstanding characteristics. Nevertheless, in the bridge-leg configuration of a power converter, the high-speed switching capability of SiC MOSFETs is often restricted by the coupling noise between high-side MOSFET and low-side MOSFET. The coupling noise caused by high dv/dt and di/dt in switching transient will increase the switching loss and the risk of MOSFET breakdown. In order to completely take advantage of the superior feature of SiC MOSFETs, a novel multilevel gate driver is proposed in this article to mitigate the coupling noise effectively. Compared to the conventional gate drivers, the proposed gate driver adds a capacitor, an auxiliary MOSFET, a Zener diode, and two resistors to regulate the turn-OFF voltage bias felicitously. In this article, the operation principle of the proposed gate driver is first introduced, to the best of our knowledge. Moreover, to obtain the circuit parameters accurately, a series of formulas have also been derived by equivalent circuit models. A 230-V/4.6-A synchronous buck converter based on SiC MOSFETs is successfully experimented to verify this proposed gate driver.