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INA180-Q1: Current calculation of INA180-Q1

CHIN NAN
Prodigy 160 points
Part Number: INA180-Q1

Hi,

Could you give the formula for getting current flowing through Rsense by output voltage of the current-sense amplifier.

I'm using INA180A2QDBVRQ1 in my design. In the data sheet it's mentioned the gain error factor and gain error %,  but not mentioned the current calculation from the output

  • 0
    TI__Expert 4620 points

    Chin,

    Thanks for the question and using the E2E forum.

    We're looking into this and will give you an update when we return from the holiday weekend.

    Louis

  • 0
    Guru 298810 points

    The current through the resistor results in a voltage drop of I × Rsense. This voltage is measured by the amplifier, and amplified by a factor of 50. So Vout = I × Rsense × 50, and I = Vout / (Rsense × 50).

    The sense resistor has an error (e.g., 1 %), the input pins have an offset voltage (150 µV near zero), and the gain has an error (1 %). So the output voltage is (I × (Rsense ± 1 %) ± 150 µV) × (50 ± 1 %), and I = (Vout / (50 ± 1 %) ± 150 µV) / (Rsense ± 1 %).

  • 0
    TI__Expert 4620 points

    Chin,

    Please see the response from Clemens (thanks Clemens!).

    Please let us know if you have any other questions.

    Louis

  • 0 in reply to Louis L
    Prodigy 160 points

    Thanks Clemens and Louis for  your reply