ZHCSKF2C February 2019 – January 2023 UCC21750
PRODUCTION DATA
The isolated analog signal sensing feature provides a simple isolated channel for the isolated temperature detection, voltage sensing and so forth. One typical application of this function is the temperature monitor of the power semiconductor. Thermal diodes or temperature sensing resistors are integrated in the SiC MOSFET or IGBT module close to the dies to monitor the junction temperature. The UCC21750 has an internal 200-uA current source with ±3% accuracy across temperature, which can forward bias the thermal diodes or create a voltage drop on the temperature sensing resistors. The sensed voltage from the AIN pin is passed through the isolation barrier to the input side and transformed to a PWM signal. The duty cycle of the PWM changes linearly from 10% to 88% when the AIN voltage changes from 4.5 V to 0.6 V and can be represented using Equation 9.