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Precise current sense amplifier for 0-10mA low side

Hal Mas
Prodigy 220 points
Other Parts Discussed in Thread: INA190, INA229, INA240

Hi all,

I am looking for a current sense amplifier to measure the current flowing in a hydraulic servo valve.

The valve is controlled with a H-bridge and the current is measured on the low side. The range of current is 0-10mA, I am planning on using 1R shunt precision resistor and a current amp with a gain of 50 or 100. I would need an analog output minimum, and SPI/I2C data optional.

I was looking at the ultraprecise INA190 but the range of the shunt resistor is between 0.001 to 100 mΩ so not suitable for my application.

Do you have any recommendation for a current amplifier with a really good precision and in my range of measurement?

Thank you

  • +1
    TI__Mastermind 20285 points

    Hal,

    Thanks for using E2E!

    The range populated in the web tool is not limitations of the device, its simply constraints on the tool due to web resources. In short, you can use a shunt outside of the bounds you see with given devices. That being said, I would caution you about using the INA190 in a switching application. Provided you are implementing on the low side, this should most likely be fine, but the switching capacitor front end of the INA190 is not designed for rapidly changing common modes. You could also have a look at the new INA241 here.

    If you need digital output, for this level of measurement, I would recommend looking at the INA229, which is an ultraprecise all in one device with digital communication. 

  • 0 in reply to Carolus Andrews
    Prodigy 220 points

    Thank you Carolus,

    I did not find the INA241, did you mean INA240 with the PWM rejection? Seems good thank you.

    I will also take a look at the INA229.