2 Channel Ultra-Precise Current Sensor

The product described here is a two-channel ultra-precise, current-sense amplifier that can measure voltage drops across shunt resistors over a wide common-mode range from 2.7 V to 120 V. The INA2290A1 chip is the heart of the project. The ultra-precise current measurement accuracy is achieved thanks to the combination of an ultra-low offset voltage of ±12 µV (maximum), a small gain error of ±0.1% (maximum), and a high DC CMRR of 160 dB (typical). The circuit is not only designed for DC measurement but also for high-speed applications (such as fast overcurrent protection, for example) with a high bandwidth of 1.1 MHz (at a gain of 20 V/V) and an 85dB AC CMRR (at 50 kHz). The project achieves ultra-precise current measurement by sensing the voltage drop across resistors R3 and R6.