A Clamping Circuit for Short Circuit Ruggedness Improvement of Discrete IGBT Devices based on the di/dt Feedback of Emitter Stray Inductance

Abstract

This paper presents a gate-voltage clamping circuit based on the negative feedback using the emitter stray inductance of discrete IGBT devices, to improve the Short Circuit (SC) ruggedness of type II and type III, which is more likely to occur in the real applications than SC type I. Specifically, during SC II and SC III, the high short circuit current $I_{\mathrm{SC}}$ increasing rate $di_{sc} / dt$ introduces an inductive voltage, which can be used to suppress the gate voltage overshoot at the beginning of the short circuit, thereby the short circuit current maximum can be reduced. Without short circuit current peak at the initial phase of the SC pulse, the energy of suppressed SC II and SC III is similar to SC type I of the same SC pulse length. The adjustable negative feedback can be achieved with a voltage divider as well.