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INA216: current sense incorrect issue

Part Number: INA216
Other Parts Discussed in Thread: INA219,

Hi Team,

Here has current sense incorrect issue from my customer that need your help for it.

    Shut resistor : 0.01 ohm ;

     Set: 0.86A current pass through the shut resistor

     Read 0X01 shut voltage=0364(Hex)=868(dec), -->868*10uV=8.68mV

     Read 0X02 bus voltage=0V

     Read 0X04 Current=10EF(Hex)=4335(dec), -->4335*1mA=4.335A

      --> From the result that it's correct for the shut voltage and bus voltage. But the current is 4.335A not the 0.86A

    Change to set the current to 0.56A pass through the shut resistor

     Read 0X01 shut voltage=0235(Hex)=565(dec)-->565*10uV=5.65mV

     Read 0X02 bus voltage=0V

     Read 0X04 Current=0B04(Hex)=2820(dec),-->2820*1mA=2.82A

As the result that current are not match, need your help for this issue and concern.

Note. Attached file has listed the the reading value, setting, and circuit.. 

 INA216 Current measuring 05092019.docx

 

    

  • Hey user4782171,

    Thanks for the explanation. I think engineer is misinterpreting what the current LSB actually is. Also, this is an application with INA219 not INA216.

    According to customer data, the calibration register (05h) = 5000h (20480 dec). This value implies that the Current_LSB = 200uA/bit, not 1mA. You can use equations (1) and (2) in the INA219 datasheet to obtain this value. This calculation assumes a 10mOhm shunt.

    Once you use 200uA current LSB, then the current measurements turn into 867mA and 564mA respectively,

    Hope this helps!

    Best,

    Peter