D25.10 - Online Condition Monitoring of Bond Wire Lift-Off in SiC MOSFETs Using Discrete Transmission Line Response to Gate Resistor Voltage in SiC MOSFET

This article presents a novel online condition monitoring technique for SiC MOSFET bond wire lift-off. A discrete transmission line (DTL), connected in parallel with the gate resistor, serves as a sensing medium. The DTL is specifically tuned to be highly sensitive to the resonant network formed by the MOSFET's intrinsic source inductance and gate-source capacitance. An increase in source inductance from bond wire degradation alters the DTL's standing wave pattern, providing a clear failure indicator. The method uniquely decouples inductance and capacitance variations by analyzing the DTL’s high- and low-frequency responses. Validated on a 500W, 100kHz buck converter using an emulated fault, experimental results showed excellent agreement with theory, confirming the technique's effectiveness.