Junction Temperature Monitoring of GaN HEMT by Using On-Resistance with Voltage Clamp and Current Shunt

Due to the unique device cell structure and power packaging of the GaN HEMT device, the online junction temperature monitoring approach of the GaN HEMT is a remaining challenge. In this paper, based on the temperature-sensitive electrical parameter on-resistance, a novel on-state resistance measurement circuit is proposed to observe the online junction temperature of the GaN HEMT. To accurately measure the on-state voltage, the proposed clamp circuit is carefully designed to remove the bias voltage of the clamp diode. Besides, the high bandwidth shunt is utilized to detect the drain current, which enables the online condition monitoring of the on-resistance. Furthermore, to ensure the validation of the proposed clamp circuit, comprehensive experiments are presented to demonstrate the junction temperature monitoring capability. The proposed circuit can be easily integrated into the gate driver or the power packaging of the GaN HEMT.