Application Note Overview 

The safe and reliable operation of high-power conversion circuits requires an understanding of junction temperature. However, the IGBT switches commonly used in such circuits require a complex set of calculations to determine die temperatures because they are often co-packaged as IGBT and diode dies. This requires that you know the power dissipation, frequency, thermal resistance values (and interaction coefficient for each die.

This paper teaches you how to measure the power dissipation of each device using waveforms from a digital oscilloscope and calculate their average and peak junction temperatures given thermal resistances and interaction coefficient of the IGBT.