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self calibration of bq27520-g4 Gauge

alpesh mandani
Intellectual 690 points
Other Parts Discussed in Thread: BQ27520-G4, BQSTUDIO, BQEVSW

Hello,

We are working on testing of battery fuel gauge bq27520-g4 chip-set with 18650 Li-ion Battery (Panasonic cell) and we have following queries.

  1. does bq27520-g4 support self calibration or not?
  2. Do we need full charging and discharging cycle for calibration of bq27520-g4?
  3. Which software require for calibration?
  4. Provide bring up guideline and calibration flow  for bq27520-g4.

Thanks,

Regards,

Alpesh

  • 0
    TI__Guru* 76230 points

    1.  No the device does not support  current, voltage and temperature self calibration. You need to perform those.The device only performs couloumb counter calibration before it goes into sleep mode to prevent drifts of the coulomb counter from occuring.

    2.You need to perform a learning cycle . See attached app note on the procedure to follow. The process isn't called calibration but rather learning cycle.

    4174.LearningCycleOverview_.pdf

    3. You need bqstudio to carry out the learning cycle. You could also get our hardware tool, called gdk to automate the process.

    4. I have attached the learning cycle document. For mass production, i recommend using the flash stream format. See attached document on using the flashstream files.

    8284.slua541.pdf

    thanks

    Onyx

  • 0 in reply to Onyx Ahiakwo
    Intellectual 690 points

    Hi Onyx,

    Thanks for your quick response.


    Please let me know how to set taper current and taper voltage in battery fuel guage.

    We have start  calibration process for full charging  and still FC bit is not to clear during full charging.

    Please help me for above issues.

    Thank

    Regards,

    Alpesh

  • 0 in reply to alpesh mandani
    TI__Guru* 76230 points
    if your design capacity for example is 4000mAH. set quit current in df to be less than 200mA. Then set dsg current threshold to be 270mA, set your chg current threshold to be 240mA, and your taper current to be 300mA. Set the taper current of your charger to be 250mA. you can keep the taper voltage as the default. Set fc set to -1 so charge termination occurs based on taper current and voltage.

    if you are still not successful send a log and gg file for review.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Intellectual 690 points

    Hi Onyx,

    We have successfully Generate Golden Image file/DFI file.
    We need to verily this golden file of gauge.

    Please let me know how to disable calibration mode for verification of Golden file or DFI file.

    Thanks,

    Regards,

    Alpesh

  • 0 in reply to alpesh mandani
    TI__Guru* 76230 points
    Alpesh
    I am not sure I understand what the request is. Once you have extracted your golden file, if you used bqstduio, the device automatically puts the gauge back into firmware mode from ROM Mode. If you used BqEVSW, you send commadnd 08 to exit ROM mode.
    thanks
    ONnyx
  • 0 in reply to Onyx Ahiakwo
    Intellectual 690 points
    Hi Onyx,
    Thanks for your support.

    We used Bqstduio and we have extracted golden file. But we are not able to update DFI file in chip-set because of FAS isn't cleared.

    Also we have used FFFFFFF key to unseals full access but FAS bit isn't cleared.

    Please let me know how to update DFI file in chip-set.

    Thank.
    Regards,
    Alpesh
  • 0 in reply to alpesh mandani
    TI__Guru* 76230 points

    Hi Alpesh,

    Since you have been able extract a golden file using bqstudio, you do not need a dfi file any more.

    With regards to FAS still set, the default ffffffff ought to work except you changed it from that value which if you did, there is nothing i can do to help unfortunately.

    thanks

    Onyx