Description

This reference design is for isolated current measurement using a shunt and isolated amplifier. By limiting the shunt voltage to 25 mV: this design is able to reduce power dissipation in the shunt and achieve a high-current measurement range of up to 200 A. Shunt voltage is further amplified by precision op amps in instrumentation amplifier-based configuration with a gain of 10 to match the input range of isolation amplifier. The output of isolation amplifier is level shifted and scaled to utilize the complete input range of 3.3-V ADC. This design uses a free-running transformer driver to generate isolated supply voltage for the high-voltage side of the circuit. Small form factor for the power supply is achieved by the operation of driver at 400 KHz.