A Technique for the In-Situ Experimental Extraction of the Thermal Impedance of Power Devices

In this letter, an innovative technique is presented, which allows the experimental extraction of the junction-to-ambient thermal impedance ( Z_TH ) of power devices operating in their application environment ( in situ ). The technique draws inspiration from the thermal characterization of RF transistors, and is based on simple measurements of electrical signals, while not requiring a thermochuck, the calibration of a thermometer, as well as temperature sensors or IR cameras. The validation of the technique is unambiguously performed by applying the “simulated experiments” strategy on an SiC-based multichip power module.