Noise-Robust On-the-Fly Measurement of the On-State Resistance of Power Semiconductor Devices

The increase in on-state resistance (RsubDUT/sub) of power semiconductor devices is used to predict its remaining useful life. In conventional RsubDUT/sub online measurement methods, the voltage across the device is measured when it is on. This voltage is affected by switching noise, thereby reducing measurement accuracy. This paper proposes a noise-robust method to monitor the increase in RsubDUT/sub by measuring an inductor current and DC input or output voltage of DC-DC converter while the converter is operating, and this method is known as on-the-fly measurement. The inductor current is robust to switching noise compared with the voltage across the device to provide high measurement accuracy. The proposed method measured the increase in series resistance to emulate the aging of a sample MOSFETs with an accuracy of up to 99%.