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BQ27220: No Current measurement after programming the OTP memory of gauge

Aditya kumar singh
Intellectual 270 points
Part Number: BQ27220
Other Parts Discussed in Thread: EV2400, BQSTUDIO

Hi,

I am using BQ27220 in my project to measure battery RSOC. Below are the CEDV parameters for my battery which I got after uploading log file-

EMF 3371
EDVC0 119
EDVC1 0
EDVR1 1
EDVR0 1
EDVT0 7695 
EDVTC 9
VOC75 3945
VOC50 3813
VOC25 3754

After getting these values, I made the golden image using BqStudio and EV2300 according to the steps defined in TRM. Then by using SmartFlash and EV2400, I have flashed OTP memory of the gauge.

Before programming, the gauge is measuring the discharging and charging current accurately but after OTP memory programming gauge is not giving any current values at all. It is always showing 0mA.

I have confirmed this issue in 2 different target boards.

Is there any specific register setting which I need to do for current values after programming?

  • 0
    TI__Guru* 76230 points
    Hi Aditya,
    Is it only the current measurement that is having issues.? Have you tried calibrating the current measurement of the gauge. How are you you carrying out the programming of the OTP, pls describe the process
    thankss
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Intellectual 270 points

    Hi Onyx,

    Steps for creating the golden image are as follows-

    1 Calibrated the gauge as per instructions given in section 3.1 in the document. Link to the same is www.ti.com/.../slua771.pdf.

    2. Updated all the CEDV parameters and battery ID in RAM of the gauge according to the instructions provided in TRM.

    3. After that created the Golden image.

    We have programmed the OTP memory of gauge according to the instruction given in TRM only. But after programming gauge is not showing current value as well as RSOC.

    When we checked the register values of the gauge, we found that calibration data is in OTP memory but same is not reflected in the RAM (attaching the image for the same)

    Gauge is always showing 32767mA charging current.

    When we flashed .OTFS file without calibration data. Gauge is always showing 0mA and RSOC is never changing even battery is fully discharged or charged. It is always showing a constant value of RSOC.

  • 0 in reply to Aditya kumar singh
    TI__Guru* 76230 points

    Aditya,

    If you perform calibration, does the calibration values get corrected and does the gauge measure current correctly?

    Can you do a compare of your files to see if it is only those three parameters that don't get change or there are more?

     I had asked that you described exactly how you are programming your OTP to ensure you are following the description in the TRM,

    FYI: We are out of office for the thanksgiving holidays so follow -up responses will not be till next week.

    thanks

    Onyx