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BQ24091: BQ24091 CHG Status

sundy xie
Intellectual 525 points
Part Number: BQ24091

Dear，

We layout a board to test BQ24091 and meet some problem.

When we set pin7 ISET2 to  High, sometimes there is no Low status output in P8 CHG during chagring stage.

If we set Pon7 float, the status of P8 is ok.

And we have try to set R24 100KΩ, but it doesn't work.

Could you give some advice? Thanks!

  • 0
    TI__Guru 65746 points
    Hello
    "When we set pin7 ISET2 to High, sometimes there is no Low status output in P8 CHG during chagring stage.
    If we set Pon7 float, the status of P8 is ok." ---- Bill J -- Pin 7 (ISET2)High will limit input / output current to 500mA, Float will limit input / output current to 100mA. Low on Pin 8 (/CHG) will indicate charge state.
    R4 is 1K and this will set the fast charge current to 540mA.
    R6 is 2k and this will set the termination current to 10% of fast charge or 54mA.
    Pin 9 ( TS ) is floating enabling TTDM mode.

    The /CHG pin will be low during charging and will go high at end of charge, input current decreases to 54mA. The /CHG pin will only go low for the first charge cycle, recharge cycles after that point will not be indicated.

    "And we have try to set R24 100KΩ, but it doesn't work."---Bill J -- R24 ( Pull up resistor for /CHG) will be a high or low and the pull up resistor value should not cause issues. But leakage current from PMIC_CHRG could cause problem with higher values of R24.

    Check the battery current during the charge states when /CHG is not indicted. Also determine if this is first charge or recharge.