Short-circuit protection scheme with efficient soft turn-off for power modules

Abstract

With the increased current density of power semiconductor devices, their short-circuit reliability becomes a critical concern, especially prominent in SiC MOSFETs, exhibiting a much narrower short-circuit withstanding time. This paper proposes an effective protection scheme utilizing a compact PCB Rogowski coil to detect the short-circuit fault fast, and an active gate clamping circuit with a soft turn-off for protection. This scheme is first experimentally verified in discrete Si IGBT and SiC MOSFET, and subsequently in power modules for both. The results confirm its benefits in decreasing overshoot drain or collector voltage, peak current, and limiting short-circuit energy to avoid thermal runaway failure. Furthermore, the influence of key circuitry parameters in the soft turn-off circuit is investigated, and the general design methodology aiming for different devices is proposed.