Reliability odometer for real-time and in situ lifetime measurement of power devices

A low-cost and compact reliability odometer is presented for the in situ real-time measurement of the residual lifetime of power devices. The proposed system is based on a mini-computer, which implements dedicated algorithms for fast and robust calculation. Starting from the sampled instantaneous junction temperature or dissipated power, the residual lifetime due to thermo-mechanical failure mechanisms is calculated both according to the Coffin-Manson scheme and by integration of the constitutive equations. A prototype is presented that works at 20 Hz sampling frequency and also offers extensive data logging capabilities.