Other Parts Discussed in Thread: XTR111,
Hello all,
I am working on a design for a AC current transducer with 4-20mA RMS output. Output from CT secondary is converted to voltage by shunt resistor and amplified with INA181 current sense amplifier. The MCU performs RMS calculation on the signal and then send the corresponding output to DAC MCP4725, whose output is converted to 4-20mA signal by XTR111.
Schematic:
My main concern with the circuit is whether the INA181 could amplify the CT output with accuracy. Since current on CT secondary (hence voltage on shunt resistor) is AC, there will be negative voltage at the inputs on each period. Altough the INA181 datahsheet states that the lower limit of common mode range is -0.2V, but I am still uncertain if it is possible (or an good idea) to amplify negative voltage input without using dual supply.
Any general advice on the circuit would be greatly appreciated, too!
Best regards,
Zhi