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Original question:

Microvolt Signal Amplification

Low side current sensing

Pritesh Metha
Prodigy 190 points
Other Parts Discussed in Thread: INA190, INA226

Hi,

I want to measure 0 to 60A current across Low side 250 uOhm 5W shunt resistor.My ADC is 10bit and max 3.3V. which would be the beast part for this.

  • 0
    TI__Mastermind 32395 points

    Hey Pritesh,

    Thank you for posting your question.

    You most likely want a current sense amplifier (CSA) with the lowest offset. The INA190 has the lowest offset (±15uV). I would recommend starting with the INA190A4 (200 V/V). So at 60A the shunt voltage is 60*250µ = 15mV, which the INA190A3 would amplify to 15mV*200V/V = 3V.

    You could use the circuit example to understand how to maximize INA190 dynamic range and calculate maximum possible error.

    http://www.ti.com/lit/an/sboa336/sboa336.pdf

    You could also use a digital device such as INA226 which has a ±10uV max, but it seems you need an analog device.

    Hope this helps.

    Peter