On-line Virtual Junction Temperature Measurement via DC Gate Current Injection

Abstract:
In mission-critical applications, the junction temperature of the power semiconductor devices is an useful parameter for determining the state of health of the power module. A possible method to measure the junction temperature on-line for a power die is by using a Thermally Sensitive Electrical Parameter (TSEP). In this paper, a junction temperature estimation method based on the DC current injection in the gate path of a power die is proposed. The selected TSEP-based method utilizes the temperature sensitivity of the internal on-chip gate resistance to estimate the virtual junction temperature of the power die. The proposed method employs a simple modification to the classical gate driver configuration. The experimental measurements show an accuracy of roughly +/-1 °C with a standard deviation of 0.4 °C. The calibrated TSEP was tested with a dynamic temperature profile to confirm the precision (around 4 °C) during the heating and cooling of the power device under PWM losses.