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In order to increase system reliability, it is an economical and efficient method to monitor the defective multichip insulated gate bipolar transistor (IGBT) modules, which are widely used in various high-power electronic systems. A method is presented to monitor chip-branches failure caused by bond-wires defects inside the multichip IGBT modules when the modules are in the off-state. It is based on that the gate input capacitance of the multichip IGBT module will be changed by the failure of chip branches caused by bond-wires defects. The change rate of gate voltage under the constant gate current can be used to characterize the failure. Firstly, according to the gate charge characteristics, the relationship between the change rate of gate voltage and the chip-branches failure under the constant gate current is given. The process of monitoring chip-branches failure is described. Then, a gate driver is presented, which contains a constant current source, and the feasibility of the monitoring method is verified. The study results show that under the constant current source driver and within the specific range of gate voltage, the change rate of gate voltage is independent of temperature and collector–emitter voltage, only related to the failure of chip branches due to bond-wires defects in the multichip IGBT module and increases significantly with the chip-branches failure. Finally, the characteristics of this method are analyzed by comparison with other similar condition monitoring methods. This method is easy to measure and can be applied to the case of real-time and online monitoring.