A Simple and Low Cost Overcurrent Protection System Based on Commercial Shunt for Wide-Bandgap Devices

Abstract:
Due to current measurement limitations in wide bandgap (WBG)-based systems, designing short circuit (SC) protection for gallium nitride (GaN) power devices is a challenging task. Currently, the most effective protection systems are based on alternative methods to current measurement. However, due to GaN's susceptibility to short circuit conditions, these methods require the design of complex circuits to meet the strict intervention time requirements. Protection methods based on direct current measurement could represent an easier solutions and help safeguard systems also from overcurrent problems. This is especially important in high-power applications where overcurrent issues can be particularly troublesome. This paper proposes a simple and fast overcurrent protection (OCP) system based on direct current measurement for 650V E-mode GaN HEMTs. The circuit is designed to quickly identify when the current exceeds the recognized abnormal limit and automatically shuts off the device under test (DUT).