Quality and System Reliability
Technical Lecture Session
Reliability of Power Conversion Systems
Safe operating area (SOA), Voltage breakdown, Current breakdown, Power switching devices, Remaining useful lifetime (RUL)
This paper investigates the effect of aging on the safe operating area (SOA) of a semiconductor device. The MTTF predicts the expected lifespan of the device, yet still cannot adequately predict the failures that interrupt the operation of a power conversion system. Existing knowledge assumes constant SOA of a device, and it fails to predict unusual circumstances and premature degradations. However, our experimental results reveal that SOA of any semiconductor device is age-dependent rather than static as considered in reported literature to-date, and this age-dependent SOA is the underlying reason for device failure especially when the device is subjected to accidental over-voltage/current. When a device undergoes aging, it suffers from reduced SOA, which decrease the MTTF of the device as well as the overall converter reliability. Therefore, by knowing the aging level, it is possible to estimate the dynamic or real-time SOA of a device, and thus, the overall reliability of the circuit can be determined.