How to get actual value of current and voltage sensing in INA220

Hi all,

 I am using INA220 for current and voltage sensing, can anyone tell actual value reading in Shunt Voltage,

Bus Voltage, power and Current. For the hex value reading got from the following registers.

 

Shunt Voltage register = 0xf060

Bus Voltage register = 0x6c32

Power register = 0x0b63

Current register = 0x1071

 

I have followed the way given in the data sheet of INA220 but it is not matching the exact value.

 

Regards,

Bharath MR

9 Replies

  • Hello Bharath,

    Are these values close to what you would expect?  Have you double-checked that the calibration register is correct for your application?  Additional details such as your common-mode voltage, load current range, and shunt resistor value and tolerance will help.

    Regards,

    Pete Semig

    General Purpose Amplifier Applications

  • In reply to Pete%20Semig:

     Pete Semi, 

    Thanks for the replay.

    I am using Vbus 12 volts but I am getting 13.8 volt and Vshunt  I am getting correct value 40mV.

    I am using calibration value 0x10d7 and Configuration Register value 0x019f.

    Regards,

    Bharath MR

  • In reply to Bharath MR:

    Hello Bharath,

    Thank you for the additional information.  Have you verfied that Vcm=12V at the input of the device?  I have back-calculated your bus voltage register contents...are you seeing a value similar to 0x6BD0?  12V would correspond to a bus voltage register value of ~0x5DC0.

    Regards,

    Pete Semig

    General Purpose Amplifier Applications

  • In reply to Pete%20Semig:

    Hello Bharath,

    Sorry, I just realized that you already reported a bus voltage register contents of 0x6C32 which does correspond to ~13.8V.  Per my previous post, has the 12V been measured at the input pins of the device?

    Regards,

    Pete Semig

    General Purpose Amplifier Applications

  • In reply to Pete%20Semig:

    Hi,

    Yes, I can able to measure 12v at the input pins of the device. Can you please suggest for further analysis.

    regards,

    Bharath MR

  • In reply to Bharath MR:

    Hello Bharath,

    Can you please share this portion of your schematic?  Also, what is the expected load current range? 

    Regards,

    Pete Semig

    General Purpose Amplifier Applications

  • In reply to Pete%20Semig:

    Hi,

    I am using INA220 test board from TI.

    regards,

    Bharath MR

  • In reply to Bharath MR:

    Hello Bharath,

    I set up an INA220EVM in the default configuration but with Vbus connected to 12V.  The bus voltage register contained 0x5DB2, which equates to 11.992V.  This corresponds to the decimal value also reported by the EVM software.

    I suggest setting up a similar situation (i.e. reverting the EVM back to default settings) to see what is reported by the EVM software.

    I hope this helps!

    Regards,

    Pete Semig

    General Purpose Amplifier Applications

  • In reply to Pete%20Semig:

    hi Pete Semig,

    thank you very much, i will set to default configuration and check.

    regards,

    bharath MR