The 1200V direct-driven SiC JFET power switch

Wide band-gap semiconductors are most attractive as materials for power devices due to low losses, improved temperature capability and high thermal conductivity. Although silicon carbide Schottky diodes have been commercially available for years, an active wide band-gap switch has still been missing. In this work, the 1200 V SiC JFET is introduced as commercially available SiC power switch. The JFET offers an excellent performance while being a normally-on device. As an alternative to get a normally-off behavior, the direct-driven JFET concept is proposed which combines a normally-on JFET with a low-voltage normally-off silicon MOSFET. An intelligent driver solution is developed to benefit from the full JFET performance. Application tests indicate excellent performance of the proposed solution.