p-GaN HEMT Hard Switching Fault Type Short-Circuit Detection Based on the Gate Schottky-Barrier Leakage Current and Using a Dual-Channel Segmented CMOS buffer Gate-Driver

Abstract

This article presents an alternative solution to the short circuit challenges commonly faced by ultra-fast power transistors. Specially 650V p-GaN HEMTs, where the short-circuit timing capability is very critical, and the presence of thermal run-aways is very sensitive. In response to this issue, a dedicated approach to detect the short-circuit inserting an on-line monitoring gate-resistor through a dual-channel segmented CMOS Gate Driver is proposed. The short-circuit indicator under Hard Switch Fault is based on the Gate-Schottky-Barrier leakage current, which is translated on a voltage drop at the gate-source voltage. The detection circuit can be fully integrated in the IC with a low monitoring voltage. A dual-buffer IC prototype including impedance state and monitoring integrated circuit using XFAB XT018 0.18um CMOS SOI technology was performed. Parametric results show a robust and quick detection propagation delay around 580ns under VDS = 400V and V GS = 5V.