INA180-Q1: Current calculation of INA180-Q1

CHIN NAN

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

over 1 year ago

0 Louis L over 1 year ago

TI__Expert 3990 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 Clemens Ladisch over 1 year ago

Guru 281870 points

The current through the resistor results in a voltage drop of I × R_sense. This voltage is measured by the amplifier, and amplified by a factor of 50. So V_out = I × R_sense × 50, and I = V_out / (R_sense × 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 × (R_sense ± 1 %) ± 150 µV) × (50 ± 1 %), and I = (V_out / (50 ± 1 %) ± 150 µV) / (R_sense ± 1 %).

0 Louis L over 1 year ago

TI__Expert 3990 points

Chin,

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

Please let us know if you have any other questions.

Louis

0 CHIN NAN over 1 year ago in reply to Louis L

Prodigy 160 points

Thanks Clemens and Louis for your reply

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INA180-Q1: Current calculation of INA180-Q1