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Original question:

INA199: Current taken by the power supply to the INA199

INA190: INA190

Ashvin Srinivas15
Prodigy 135 points

Part Number: INA190
Other Parts Discussed in Thread: INA199

I would like to use the INA190  instead of the INA199. As noticed earlier with the INA199, the supply current to the chip increases when the output goes beyond the linear region.

Should I expect the same to happen with the INA190 as well?

  • 0
    Guru 140200 points

    Hi Ashvin,

    how much did the supply current increase? And how much increase would be acceptable for you?

    Kai

  • 0 in reply to kai klaas69
    Prodigy 135 points

    The current increased to approx. 1mA with the INA199, with the INA190, during actual testing, it did not seem to increase much as in the INA199.

    Acceptable would be a current less than 100uA. 

  • 0 in reply to Ashvin Srinivas15
    TI__Mastermind 32395 points

    Hello Ashvin,

    Thank you for your question.

    • What is your output load during testing? So is the INA199 driving a 10kOhm resistor or some other resistance (1k, 500-Ohm, etc)?
    • Could you explain how you define the linear region? What input shunt voltage (Vsense) and output voltage (Vout) values define this?
    • What is your system's bus voltage? So what is the common-mode input voltage (VCM) at device input pins?

    As the Vsense increases, the Vout will also increase leading to more output current (Iout) to drive any resistive load. So total supply current will always be IQ + Iout. Depending on your load, the linear output region can become limited by the Iout vs. Vout claw curve.

    Aside from this typical amplifier behavior described above, the INA199 and INA190 are quite different in terms of architecture. I will note that as Vsense approaches ~250mV for the INA190, the input bias current will jump  dramatically (in the uA), but this will not cause an increase in INA190 supply current.

    Sincerely,

    Peter

  • 0 in reply to Peter Iliya
    TI__Mastermind 27715 points

    Hello Ashvin,

    It's been some time since your last post, so I hope your issue was resolved. If you need more help, please reply and we can continue to assist.

    Best regards,

    Ian Williams
    Applications Manager
    Current Sensing