The TIDA-00442 TI design provides a reference solution for detecting ground faults in inverter based drives. Inverter current is measured on both dc-positive and dc-negative buses using shunt resistors. Current on the dc-positive bus is measured using INA170 which is powered by a low-side switched buck converter. Current on the dc-negative bus is sensed using precision op amps. The difference between the two measured currents is compared against a fixed threshold using high speed comparators to determine the ground fault condition.
- 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
Parts Include:
INA170 60-V, High-Side, Bi-Directional, High-Speed, Current Output Current Shunt Monitor
OPA2376 Precision, Low Noise, Low Quiescent Current Operational Amplifier
REF2033 Low-Drift, Low-Power, Dual-Output VREF and VREF/2 Voltage Reference
UCC28880 High Voltage Switcher for Non-isolated AC/DC Conversion
TLC372 Dual General Purpose LinCMOS(TM) Differential Comparator
Learn more by downloading the reference design below
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