Indirect Thermographic Temperature Measurement of a Power-Rectifying Diode Die Based on a Heat Sink Thermogram

This article concerns the indirect thermographic measurement of the junction temperature of a D00-250-10 semiconductor diode. Herein, we show how the temperature of the semiconductor junction was estimated on the basis of the heat sink temperature. We discuss the methodology of selecting the points for thermographic measurement of the heat sink temperature and the diode case. The method of thermographic measurement of the heat sink temperature and the used measurement system are described. The simulation method used to obtain the temperature of the semiconductor diode junction on the basis of the thermographic measurement of the heat sink temperature, as well as the method of determining the emissivity and convection coefficients, is presented. In order to facilitate the understanding of the discussed issues, the construction of the diode and heat sink used, the heat flow equation and the finite element method are described. As a result of the work carried out, the point where the diode casing temperature is closest to the junction temperature was indicated, as well as which fragments of the heat sink should be observed in order to correctly estimate the temperature of the semiconductor junction. The indirect measurement of the semiconductor junction temperature was carried out for different values of the power dissipated in the junction.