Series-connection of SiC normally-on JFETs

The SiC normally-on JFET is a new member in the family of power devices. It is reliable and robust under high-temperature and high-voltage harsh operatioing conditions due to its pn-junction gate control and the excellent physical and electrical properties of Silicon Carbide. At present, 1200V SiC normally-on JFETs are commercially available and higher voltage JFETs are still under development. There is a strong need for a medium-voltage 4kV-15kV power switch that can be moved into mass production quickly, exploits all the material advantages of SiC technology, and is cost-effective. This work presents an innovative method to realize such a high voltage power switch by series-connecting low voltage SiC normally-on JFETs using a unique circuit topology. This work focuses on the discussions of the operation principle and the experimental demonstrations of the proposed technique.