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  • TI Thinks Resolved

BQ24297: BATFET can't normally turn on

Intellectual 290 points

Replies: 7

Views: 136

Part Number: BQ24297

Hi,

We meet an issue about BQ24297 BATFET can't normally turn on, please see below SYS pin waveform, BATFET turn on/turn off each ~170ms, seems meet some error after turn on BATFET, but I check the register only see the REG09[7] WATCHDOG_FAULT is 1. And other strange is REG01[5] OTG Enable is 1.

This symptom can be release after remove battery, we have 2 device, we have tried one to remove battery, and keep one still have this fail symptom.

Do you have ever meet this issue or any possible fault caused BATFET can't turn on normally?

CH1: SYS pin

CH1: SYS pin

CH2: BAT pin

Register table

schematic

thanks!

Jeff

  • Hi,

    Are you trying to operate in charge mode or OTG mode? Please set REG01[5:4]=10 or REG01[5:4]=01 and try again.

    Thanks,

    Ning.

    Please click "This resolved my issue" button if this post answers your question.

  • In reply to Ning T:

    Hi Ning,

    Could you please explain why you want set REG01[5:4]=10 or REG01[5:4]=01?

    Are you consider REG01[5:4] should not be "11"?

    But we only have one device have this fail symptom, I'm worry about if set REG01[5:4]=10 or REG01[5:4]=01 then fail symptom disappears.

    Is there have any other way to know BQ24297 is which status?

    Thanks!

    Jeff

  • In reply to Jeff Yang76:

    Hi Ning,

    Any update for this issue?

    Or we can plan a conference call to discuss this issue?

    Thanks!

    Jeff

  • In reply to Jeff Yang76:

    Hi Ning,

    Update one more information, we had write REG04[0] "VRECHG" from 0 to 1, and tried read back this register still "1",

    it mean BQ24297 is active and can be write by host.

    And another question,

    How does the watchdog  timer work? As I know, BQ24297 can be work stand along without host, and use default register setting to charge.

    It means even no I2C signal still can work. But watchdog timer seems needs I2C period kick BQ24297 to let it normal  work.

    Or under stand along charging, it used other signal to kick watchdog? or it does not need watchdog timer in stand along charging?

    Thanks!

    Jeff

  • In reply to Jeff Yang76:

    Jeff,

    Referring to 9.4.1 Host Mode and Default Mode on the d/s, the device is can operate in default mode without host management. In default mode, the device can be used as an autonomous charger with no host or with host in sleep. In default mode. All the registers are in the default settings.

     

    Any write command to device transitions the device from default mode to host mode. All the device parameters can be programmed by the host. To keep the device in host mode, the host has to reset the watchdog timer by writing 1 to REG01[6] before the watchdog timer expires (REG05[5:4]), or disable watchdog timer by setting REG05[5:4] = 00.

    Thanks,

     

    Ning.

     

    Please click "This resolved my issue" button if this post answers your question.

  • In reply to Ning T:

    Hi Ning,

    I saw the watchdog explanation, thanks for the information.
    But any update for the BATFET can’t normally turn on issue?
    Except write set REG01[5:4]=10 or REG01[5:4]=01, do you have any other suggestions?
    We have 2 fail device but 1 device fail symptom disappears after remove battery. We now only have 1 fail device on hand, and still try to reproduce and find other fail device.
    So we worry about if set “REG01[5:4]=10 or REG01[5:4]=01” will let the fail symptom disappear, we need to know BQ24297 in what status and find root cause.

    Thanks!
    Jeff
  • In reply to Jeff Yang76:

    Jeff,

    This thread is being handled via separate resource. It is considered closed here.

    Thanks,

    Ning.

    Please click "This resolved my issue" button if this post answers your question.

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