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INA213: INA213 Calculation problem of solar panel ( or power supply) current for charging battery

user5282208
Prodigy 20 points
Part Number: INA213

I built microcontroller based( arduino nano) solar battery charger unit. I added the schematic. I set up the circuit and try it with adjustable power supply instead of solar panel for input. I read voltages and output current correctly ( but  output current value need calibration ) , but I cannot correctly read input current. While I am changing the input voltages ( current on power supply screen changes ), INA213 of input is always same value ( like 2110 mA ) and never changes. I tried it on many different pcb boards but it is same. What should I do? Is INA213 eaisly broken down? 

Could you help me ? 

(  I choose shunt resistor as R040 ( 40m ohm) ( arduino is 5V and current range 0.01-2A =>  (5/50)/2 = 50 mohm so I choose R040 . Is there a mistake of calculating and choosing shunt resistor) )

And I want to learnd accuracy of INA213 in that condition? 

Best Regards

 

  • 0
    TI__Mastermind 24135 points
    Hello user5282208,

    Thanks for considering to use Texas Instruments. So if I understand correctly, you are getting correct readings from U3, but not from U1? Are you using the INA213A version, INA213B version device, or INA213C version device. If you are you the A version device, you should switch to the B or C version of the device. Those have more robust ESD structures that are better equipped for handling a quick power-on. Aside from swapping out the device, you may try isolating the device from downstream devices to rule out whether those might be doing something unexpected to the output.
  • 0 in reply to Patrick Simmons
    Prodigy 20 points

    Dear Patrick,

    I used A series. I ordered B and C series. I will try. But I can read stable current fo rinput. I change power supply's voltage but there is no change in input current ( U1 ). But I can read changeable values according to input voltage from output current ( U3 ). 

    In other PCB, I just soldered U1, voltage divider and input. In this case, I can read some values. But I am confused. What should I do? And I want to try the circuit in TINA Design Suite. I cannot find IR2104 ( or any gate driver like that). Could you help me try this circuit in TINA ? I want to correct stability of circuit.

    Best Regards

  • 0 in reply to user5282208
    TI__Expert 5705 points
    Hello,

    You can just use independent AC voltage sources (or "voltage generators" in TINA) to model the gate driver outputs in SPICE. Alternatively, the vendor may have a SPICE model of the IR2104, which you can import into TINA as a macro (via Tools->New Macro Wizard). Please check with the vendor.

    Also, the value of RSHUNT may be marginal considering your supply voltage tolerance, output swing to positve rail and RSHUNT tolerance. For example a 10% lower supply voltage would mean that the INA output saturates at 4.5 - 200mV (swing to V+) = 4.3V. If the INA and RSHUNT are ideal then the input-referred value corresponding to a 4.3V output is 2.15A, which is very close to the saturated value you are observing. Have you tried using a smaller value for RSHUNT (say 25mOhm)? Only R1 may need to be changed because it appears the average input current would be greater than the average output current (i.e. Iaverage(R1) = Iaverage(Q2) + Iaverage(R2), and Iaverage(Q2) > 0).

    Best Regards,
    Harsha