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BQ27510: startup of the Bq27510 battery gauge

Shrikrishna B
Prodigy 170 points
Part Number: BQ27510
Other Parts Discussed in Thread: BQSTUDIO

Hello,

I have questions concerning the startup of the Bq27510 battery gauge:

  1. Is it sufficient to monitor the INITCOMP bit to determine if the gauge has initialized completely and correct, or are there other bits to take into account as well?              
  2. What is the maximum time it takes after connecting the battery before the INITCOMP goes high (or initialization to be finished)?
  3. The coulomb counter calibration routine will start after initialization (indicated by CCA). Will finishing it change the charge level determined by the gauge at initialization, or can we rely on the value as already determined?

Any help on this would be highly appretiated, as it is blocking our development,

Thanks

Shri

  • 0
    TI__Guru* 76230 points
    Hi Shri,
    1. Yes. The Initcomp is sufficient.
    2. It takes about 2.5 secs to get set. I recommend waiting 3 secs to give enough buffer.
    3. you can rely on the value as correctly determined. This is for the cc offset values. You still need to do current , voltage and temp calibration otherwise you use the average calibrated values of 10 calibrated boards.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 170 points
    Hi Onyx,

    Thanks for the reply. We do have another question though; in our system we have seen that the gauge occasionally does not complete the initialization.
    The control flags observed are:

    23:50:26.332 PowerUp
    23:50:30.661 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:31.157 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:31.669 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:32.165 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:32.677 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:33.173 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:33.685 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:34.182 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:34.694 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:35.190 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:35.701 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:36.197 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:36.693 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:37.205 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:37.701 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:38.213 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:38.709 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:39.221 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:39.717 Log: BatteryGauge startup: Control flags not correct; value: 0x0A0C
    23:50:40.229 Log: BatteryGauge startup: Control flags not correct; value: 0x020C
    23:50:40.725 Log: BatteryGauge startup: Control flags not correct; value: 0x020C
    23:50:41.237 Log: BatteryGauge startup: Control flags not correct; value: 0x020D

    The gauge has about 14 seconds from power up, and according to the flags the OCV command has completed without failure (OCVCMDCOMP = 1, OCVFAIL = 0).
    We do however not see that the initialization is complete (INITCOMP = 0). Can you tell us about the circumstances the gauge would not be able to complete the initialization?

    Thanks in advance.
  • 0 in reply to Shrikrishna B
    TI__Guru* 76230 points

    The gauge has to detect a battery is inserted for the initcomp flag to set. Do you have a thermistor connected to the ts pin as shown in the reference schematic in the evm user guide? if you are not using a thermistor, the BIE flag has to be set and your host has to send the bat det command.

    thanks

    Onyx

  • 0 in reply to Onyx Ahiakwo
    Prodigy 170 points

    Hi Onyx,

    Thanks for reply. We do check the status flag for battery detect, and we have thermister connected. So that all seems to be in order.

    Could there be any other situation(s) which causes gauge to become unable to complete its initialization, for instance fluctuating current or voltage or something like this?

    Thanks

    Shrikrishna

  • 0 in reply to Shrikrishna B
    TI__Guru* 76230 points
    Hi Shrikrishna,

    That is the only instance that comes to mind. Can you share your a screen shot of the bqstudio and perharps a bqstudio log and gg file.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 170 points
    Hi Onyx,

    Thanks again for the reply. We do not have bqstudio connected, our software checks the gauge's registers. We must confess that in these cases we use a simulation device; it has the NTCs and provides a voltage to 'simulate' a full battery. We have not seen the initialization issues with real batteries - your reply indicates to us that our simulation device might not be stable all the time. As it does not reproduce well we needed to know what could throw the gauge off.
    Thanks for your help on this.

    Thanks
    Shrikrishna