INA219: offset current value through I2C when real Iout=0A

Part Number: INA219

Hi, team,

If INA219 real current through shunt is Iout=0A, we can read the current is xA through I2C. And when Iout increases to yA, read current value is (x+y)A.

1. Is it caused by ADC shunt offset as shown below?

2. How to calibrate the offset?

Thanks.

Johnny

  • Hi Johnny,

    Thank you for posting on the E2E Forums.

    Yes, the readings are due to the device offset and, if your application requires that level of precision, will need to be subtracted from the total read current.

    There is no way to cancel the offset. The options are as below:

    • At startup with I = 0A, save the reading as a constant and subtract it from all future measurements
    • Switch to the INA233, which is a zero offset part

    Kind Regards,

    Carlos S., TI Sensing Products, Applications Support

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.