A SiC JFET driver for a 5 kW, 150 kHz three-phase PWM converter

Silicon carbide (SiC) power semiconductor devices are capable of being operated at higher voltages, frequencies and temperatures than silicon power devices. These SiC device capabilities will provide the power electronics designer with new possibilities to produce compact designs. Presently the JFET is the only controlled turn off/on SiC device that is close to commercialization and available as restricted samples. However the JFET is a normally-on device that requires a negative gate voltage to turn off. In order to correctly design a gate driver one must understand the characteristics of the JFET. This paper presents a description of the JFET semiconductor structure, and the SiC JFET´s static and dynamic characteristics from room temperature to 200 °C. A SiC JFET gate driver circuit is presented and its performance described. The proposed gate driver improves the switching performance of the JFET by operating the gate in avalanche during the off time.