CMOS Gate Driver with fast short circuit protection for SiC MOSFETs

Abstract

This article presents an alternative solution to the short circuit challenges commonly faced by SiC MOSFETs power transistors. In response to this issue, a dedicated fast CMOS active gate driver AGD is designed to detect the short circuits and to protect SiC MOSFETs, using only low voltage analog functions (5V and 40V transistors). The external high voltage diode used in the desaturation monitoring technique is no longer required and the short circuit detection can be much faster based only on signals observed by the gate driver. The IC prototype is based on XFAB XT018 0.18um CMOS SOI technology. The novel detection circuit is based on a 2D diagnosis, without any time dependency, fully integrated, with a low monitoring voltage. Detection of SC events is between 35ns and 130ns depending on the input capacitance of the power transistor, the internal/external resistors, detection threshold levels.