Power cycling test with power generated by an adjustable part of switching losses

In standard power cycling tests, forward conduction generates heat in the die and therefore the ther-momechanical stress in the package. In application, however, a significant part of the power losses are switching losses, so that the load current is lower than in standard power cycling test, for an equal temperature swing. A new concept for power cycling tests is presented, which allows the generation of switching losses in addition to conduction losses. This concept closer to the real application. The circuit still uses a low voltage power source, while maintaining an accurate measurement of the virtual junction temperature. First test results of IGBTs in standard module technology and SiC MOSFETs in discrete TO-247 housing indicate no significant difference in results from standard power cycling tests. The new method was successfully applied to low voltage Si MOSFETs, which is for the first time applied to such a power cycling test under conditions where switching losses dominate.