Shunt-Based High Current Measurement (200A) Reference Design Using Reinforced Isolation Amplifier

The TIDA-00912 TI reference design provides a complete isolated current measurement reference solution using an external shunt, reinforced isolation amplifier, and isolated power supply. Parallel voltage is limited to 25mV. This reduces power dissipation in parallel connection, enabling high current measurement ranges up to 200A. The shunt voltage is amplified by an instrumentation amplifier configuration with a gain of 10 to match the isolation amplifier input range for better signal-to-noise ratio. The output of the isolation amplifier is level shifted and adjusted to match the full input range of the 3.3V ADC. This design uses a free-running transformer driver operating at 410kHz to generate an isolated supply voltage in a small form factor to power the high-voltage side of the circuit. 

characteristic

• ● Shunt-based 200A peak current measurement solution with reinforced isolation
• ● Limit the parallel voltage to 25mV to reduce power dissipation
• ● The high-side current sensing circuit has a high common-mode voltage of 1500V (peak) and supports AC mains powered drivers up to 690V
• ● Calibrated AC accuracy is less than 1% over the temperature range of -25 ^o C to 85 ^{o C}
• ● Can be directly connected to differential or single-ended ADC
• ● Push-pull small isolated power supply can power high-side circuits