IGBT Junction Temperature Measurement via Peak Gate Current

An electrical method for junction temperature measurement of MOS-gated power semiconductor devices is presented. The measurement method involves detecting the peak voltage over the external gate resistor of an insulated-gate bipolar transistor or MOSFET during turn-on. This voltage is directly proportional to the peak gate current, and fluctuates with temperature due to the temperature-dependent resistance of the internal gate resistance. Primary advantages of the method include an immunity to load current variation, and a good linear relationship with temperature. A measurement circuit can be integrated into a gate driver with no disruption to operation and allows autonomous measurements controlled directly via the gate signal. Advantages and disadvantages of the method are discussed.