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Original question:

BQ25896: INT pulse which is relation to NTC Fault Status

BQ25896: BQ25896 NTC fault status and INT pulse clarification

Niclas Arndt
Intellectual 425 points
Part Number: BQ25896

Hi,

Could I ask you to clarify the response provided to the question in the link below?

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/681229/bq25896-int-pulse-which-is-relation-to-ntc-fault-status?tisearch=e2e-sitesearch&keymatch=BQ25896%2520cool#

At which of the below state transitions is an INT pulse issued?

TS Normal -> TS Warm

TS Warm -> TS Hot

TS Normal -> TS Hot

TS Normal -> TS Cool

TS Cool -> TS Cold

TS Normal -> TS Cold

TS Warm-> TS Normal

TS Hot -> TS Normal

TS Hot -> TS Warm

TS Cold -> TS Normal

TS Cold -> TS Cool

TS Cool -> TS Normal

TS Cool or Cold -> TS Warm or TS Hot

TS Warm or TS Hot -> TS Cool or Cold 

...and any state transition I forgot to enumerate in this tedious listing. ;-)

Best regards

Niclas

  • 0
    TI__Guru 52131 points

    Niclas,

    Assuming normal operations and no other INT triggering events besides TS fault, a new INT pulse will only be generated when REG0C=00 then TS event occurs. e.g. REG0C=00 then TS changes from normal to cool, a new INT pulse will be generated. If the device is in TS Cool already (i.e. REG0C<>00), the device will not send another INT pulse when TS Cool changes to TS Cold.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Intellectual 425 points

    Hi Ning and thank you,

    So, after the single INT pulse at TS Cool or TS Warm, is the recommended way to get unambiguous information about battery temperature-related charge termination to periodically poll REG0C->NTC_FAULT?

    Or is REG0B->CHRG_STAT a better status bit field to poll for value 00 Not Charging / 11 Charge Termination Done?

    Best regards

    Niclas

  • 0 in reply to Niclas Arndt
    TI__Guru 52131 points

    Niclas,

    Once the device enters and keeps a TS fault, there will not be subsequent INT pulses due to TS fault type changes. The host should read the registers regularly to obtain the latest charger status.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Intellectual 425 points

    This is annoying and a waste of time.

    If you are working for TI and don't know the answer, please escalate to somebody who knows.

  • 0 in reply to Niclas Arndt
    Intellectual 425 points

    This question is probably indirectly answered by the interpretation of the response in this other posting:

    https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1022246/bq25896-bq25896-reg0b--chrg_stat-transition-after-charge-termination

    REG0B->CHRG_STAT will show '00 Not Charging' if charging is halted due to TS Cold or TS Hot but might presumably change back to '01 – Pre-charge' or '10 – Fast Charging' if temperature returns to TS Cool, TS Normal, or TS Warm. I suppose that unless you actively stop charging, you might in effect have a charge start-stop loop when going in and out of '00 Not Charging'.

    Assuming you are periodically (in sufficiently short intervals so that battery temperature doesn't have time to change too much) reading all relevant status registers, it's the REG0C->NTC_FAULT bits and possibly also REG10->TSPCT that will tell you if you have entered TS Cold or TS Hot, in which case you should probably change to SW control of if and when to retry. Especially if you enter TS Hot, you might want to inhibit charging until the battery has been exchanged.