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ina226 interfacing with ATMEGA32A problem

Iydah Grace
Prodigy 80 points

Other Parts Discussed in Thread: INA226

Iydah Grace posted ina226 interfacing with ATMEGA32A problem in Make the Switch to TI MCUs Success Stories.

I have programmed for atmega32 to read the current and voltage from ina226.(load-1.7A,12V)

Though It was working well and i got the current  and shunt voltage correctly,I couldn't read the bus voltage(without common ground)..

so i went to common ground,but it bursts my ina226and read nothing. After that i use the regulator (12v to 5) but it doesn't work.

voltage b/w ina226 supply and load ground is 12v...The voltage b/w load ground and ina226 ground is -12v (without common grounding). This case i can read current and shunt voltage only.

voltage b/w ina226 supply and load ground is 12v...The voltage b/w load ground and ina226 ground is -0.76v(with common grounding). In this case ina226 is heating and i can't read anything..

Please help me to find the solution

  • 0
    TI__Genius 12375 points

    Iydah,

    Without knowing what your load is, or seeing a detail schematic for your system it is difficult for us to offer solutions. However, I can point out that the maximum supply voltage of the INA226 is 5.5V, so if you are shorting the grounds together and applying 12V to the supply of the INA226 then you will damage the part (this also explains why it is getting hot).

    The fact that there is a 12V difference between your load ground and your power supply ground makes me think that either your load is being driven in a floating configuration (not referenced to ground) or that the load current is so large that the resistance of its ground pathway is causing a significant voltage to develop. If the load is indeed floating then it would be best to examine isolating circuits to perform the measurements. In an isolated measurement the INA226 would share the same ground with the load and would transfer the readings to other circuitry using a digital isolator.

  • 0 in reply to John Caldwell
    Prodigy 80 points

    Thanks John.

      I have attached circuit diagrams of my project.. From  the ckt dgm 1,i can get the current(1.7A) and shunt  voltage(13mv), not the bus voltage(some garbage like 3.344).

    From ckt dgm 2,i can get nothing and sensor also bursts,even i refer this circuit from ina226 datasheet (page no 15).

    4135.ckt dgm 1.pdf  

    3704.ckt dgm 2.pdf

     

  • 0 in reply to Iydah Grace
    TI__Genius 12375 points

    Iydah,

    From your diagrams it would appear that you are supplying both the load and the INA226 from the negative outputs of your power supplies? Are the power supplies referenced to the same ground? In other words, what is the other terminal of the power supplies in your diagram connected to? What are you using for power supplies? Are these laboratory power supplies or something else?

  • 0 in reply to John Caldwell
    Prodigy 80 points

    Thanks John..

      ya,very sorry, my diagram was wrong..I don't have knowledge in orcad design..But now i attached correct one..I have one more problem too..Even I get the current and shunt voltage from the  ckt diagram 1, i can't read 0 current while,removing my load..I hope you apologize me for wasting your time and my bad English..

    0284.ckt dgm 1.pdf

    3021.ckt dgm 2.pdf

  • 0 in reply to Iydah Grace
    Prodigy 100 points

    Hi, Iydah!

    ...i can't read 0 current while, removing my load...

    You will read 0 current with removing  sourse +12 V, not removing load.