A Novel Local Voltage Sensing Mode for High Voltage IGBT Sensor

Collector-emitter voltage (Vce) detection of insulated gate bipolar transistors (IGBTs) is important for safety-critical and mission-critical power applications. The conventional voltage sensing method is characterized by the detection range from 0 V to the rated voltage in application (Vr), which is limited by the contradiction between the dynamic range of the signal and the ADC resolution in high voltage situations. Therefore, this study proposes a novel local voltage sensing (LVS) mode, in which the detection range is from Vst to Vr, where Vst is the controllable starting voltage of the sensed IGBT. Based on LVS mode, a novel controllable voltage sensor structure is given, which can provide a sensing signal that is a scaled version of the large Vce when Vce Vst. Vst can be controlled by applying a negative voltage to a control electrode gate (VG2). An analytical model is derived to understand the mechanism of the sensor and simplify the design. The effects of internal and external parameters on the sensing characteristics are simulated by Medici & TS4. Furthermore, the sensor is incorporated into a trial-manufactured 1200 V IGBT, and the experimental results agree with the analytical results.