Optically Triggered Power Switch Based on 4H-SiC Vertical JFET

Abstract

An optically controlled power switch based on 4H-SiC Trenched and Implanted Vertical JFETs (TIVJFET) was developed that comprises three parts: an LED light-source driver, light-triggered integrated gate buffer driver, and vertical high power normally-off switch. The light-triggered integrated gate buffer driver includes a photodiode and four stages of low voltage 4H-SiC TIVJFETs, which are hybrid integrated. Optically gated power switching was experimentally demonstrated with a maximum switching frequency of about 50 kHz, the system performance limiting factors were clearly identified and experimentally confirmed, and ways to substantially increase the switching frequency were shown. From calculations, based on realistically possible system parameters values, it could be seen that a maximum switching frequency around 1 MHz is theoretically possible with a proper choice of light source, detector, and buffer transistor parameters.