# Amplify+level-shift sine signal

I am working on current sensing for three phase inverter outputs, wherein I plan to use a shunt resistor for getting a low voltage sinusoidal current waveform. Is there any way at all that could convert 0.001V peak sine wave (50Hz) to 0-5V sine wave?

• Instrumentation amplifiers (random example: INA821) can do this. Or do you want to do this with plain opamps?
– CL.
Commented Oct 6, 2023 at 9:23
• The current waveform depends on the load and the inverter output voltage sine quality so, what prompts you to say it will be sinusoidal? There could be many harmonics present so, you might need to take this into account. 1 mV to 2.5 volt is a gain of 2500 and, this is achievable for moderate bandwidths with reasonable accuracy so, what accuracy are you requiring? Commented Oct 6, 2023 at 9:31
• What is the value of your shunt? Depending on the circuit you choose you might require isolation. How much current is going through the outputs? How accurate do you need to be? Inductive pickup may or may not be a better fit. You should show a diagram. Commented Oct 6, 2023 at 14:03
• @Reinderien I am using 100micro ohm as the value of shunt. The inverter output is designed to carry 70A of rms current. However, I have selected the shunt considering 300A (including harmonics, spikes or to assist tuning of the drives). The more accurate it is the better it would be as I am planning to use the currents in the control algorithm after sensing them. How much accurate can I really get with opamps? Commented Oct 9, 2023 at 7:15
• @Andyaka I have considered the worst case scenario wherein 300A would be the output of the inverter. As I am driving inductive loads I am not worried much about harmonics. For accuracy, do you recommend this circuit to be used for sensing real time currents for current control algorithms? Commented Oct 9, 2023 at 7:18