A Detection Method of Gate Open-Circuit Failure in SiC MOSFETs Based on Internal Gate State Extraction

Gate open-circuit failure caused by the cracking and liftoff of gate bond wires has been demonstrated to be a new failure mode of SiC MOSFETs, which can cause serious consequences such as the shoot-through fault and gate-oxide breakdown. To enhance the reliability and robustness of SiC MOSFETs, a fast and accurate detection scheme of such failure is required. This letter proposes a gate open-circuit failure detection method based on the internal gate state extraction. This state, although is unavailable externally, can be extracted from gate current pulses. The gate open-circuit failures are then detected by checking the inconsistency between the drive signal and the internal gate state. Experimental results validate that the proposed method can detect all types of gate open-circuit failures accurately within 55ns.