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INA280-Q1: High voltage supply current sense issue

Pooja Gurram
Prodigy 10 points
Part Number: INA280-Q1

Hi.,

In one of our motor controller project, using current sense IC -Part Number-  INA280A2QDCKRQ1.

With this current sense IC, we are using 1mOhm/5W shunt resistor for measuring 60A current flowing through supply voltage.

The problem is, whenever we are changing different shunt resistors with the same value, getting different output with the accuracy difference of 5 to 10%.

We tried with input filtering also for the current sense IC, but there is no any result change.

Kindly, let us know some solution for it.

  • 0
    Guru 140200 points

    Hi Pooja,

    please specify the measuring error. Is it gain error, offset error or linearity error? Please show a schematic and your layout.

    A four terminal shunt can do the trick in the most cases.

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 28760 points

    Hello Pooja,

    Normally the Rshunt can have the largest variation.  Besides the normal resistance variation you also need to account for the drift of the device especially since you are sending current that could heat up the resistor.   What is the specification of the resistor you are using?  What is the drift of the resistor?  When replacing the resistor is there anything that could lead to dissipation of power to be different?

    Like Kia suggested a schematic and layout can help narrow down the variation.