Failure Protection in Power Modules with Auxiliary-Emitter Bond-Wires

Abstract:
This paper provides a proof-of-concept for how auxiliary-emitter resistors (or auxiliary-source resistors in MOSFETs) can be used as sensors that accurately detect when a power module has reached the end of its life, and thus avoid catastrophic failure. Use of auxiliary-emitter resistors in this way allows failures to be detected in under one switching cycle. In addition, the auxiliary-emitter resistor ensures that gate control is maintained even after complete lift-off of the power bondwires. These two features permit instant implementation of a fault control strategy in order to avoid power module explosion. Conversely, if an auxiliary-emitter resistor is not included, gate control is lost and the module completely fails through thermal overload or gate latch-up within seconds.