Evaluation of IGBT thermo-sensitive electrical parameters under different dissipation conditions – Comparison with infrared measurements

Junction temperature evaluation is a key parameter used to control a power module assembly. But measuring the junction temperature by thermo-sensitive electrical parameters (TSEPs) does not reveal the actual temperature of the semiconductor device. In this paper, a specific electronic board used to compare four common TSEPs of IGBT chips is presented. For this comparison, two dissipation modes are used: dissipation in active and saturation regions. In order to have referential measurements we carried out surface temperature measurements of IGBT chips with an infrared (IR) camera. A dedicated numerical tool is presented to estimate the mean surface temperature of active region. In the case of a single IGBT chip, the comparison between IR and TSEP measurements show that the best studied parameter (in terms of robustness and usability) is the gate emitter voltage.