In-situ Monitoring Chip Failure in Multichip IGBT Modules Using Turn-on Delay Time Extracted from Auxiliary Emitter Voltage

Power semiconductor chips are used in parallel within the module to achieve a specific current capacity and power level. One of the most common failure modes of power modules is bond wires fatigue. Monitoring the health conditions of the chip is a cost-effective method to improve the reliability of the power module. This article uses auxiliary emitter voltage to monitor the chip open-circuit failure caused by all bond wires lift-off. The impact of chip failure on the switching process is analyzed, and four electrical parameters are extracted as health monitoring parameters (HMPs). The dependence of proposed HMPs on operating conditions such as gate resistance, bus voltage, load current, and junction temperature are investigated by experiments. The comparative analysis of the four HMPs shows that the turn-on delay time t _don has high sensitivity and the strongest anti-interference ability. Finally, an on-line monitoring circuit for in-situ detection of chip failures in multichip IGBT modules is designed. The circuit can be plug-and-play or integrated into the gate driver. The results show that a reduction of 276ns in the measured t _don for each IGBT chip failure.