In-situ Bond Wire and Solder Layer Health Monitoring Circuit for IGBT Power Modules

An in-situ bond wire/solder health monitoring circuit is proposed that is an integral part of an electric drive. The circuit monitors the health of wire bond interconnections and solder joints within a power module. The bond wire and solder joint degradations are emulated externally for this study and an interruptive monitoring (I-Monitoring) process is activated repeatedly at predefined conditions. The forward voltage drop and junction-to-reference thermal impedance of each individual IGBT and diode are measured individually and they are used as failure precursors. Any rise at predefined conditions is regarded as an early symptom of wear-out of the power-module. The circuit and measurement technique proposed here are ideal for field testing of newly developed power modules to determine the health of both bond wires and solder joints. Experimental results are presented to demonstrate the capability of the proposed method.