View the Important Notice for TI Designs covering authorized use, intellectual property matters and disclaimers.
- Shunt-Based Ground Fault Protection for Inverters Design Guide (Rev. A)
(PDF 4967 KB)
20 Aug 2015 713 views
The TIDA-00442 TI design provides a reference solution for detecting ground fault in inverter based drives. Inverter current is measured on both DC positive and DC negative bus using shunt resistors. Current on DC positive bus is measured using INA170 which is powered by low side switched buck converter. Current on DC negative bus is sensed using precision opamp’s. The difference between the two measured currents is compared against a fixed threshold to determine the ground fault condition using high speed comparators.
- Shunt based current sensing for inverter control and protection
- Rated to measure DC Link current of +/-20APK (Design tested for +/-5A)
- High side current sense circuit with high common mode voltage of +450V supporting 220Vac mains powered drives
- Calibrated high-side and low-side measurement error over operating temperature range of -10°C to 55°C < 1.5%:
- Ground fault: (Minimum fault current detection of 300mA, Detection time of less than 50µs)
- Designed to be interfaced with built-in 3.3V ADC of MCU