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Original question:

BQ25898: STAT=Low condition

BQ25898: STAT Low at discharge state

Toshiro Imi
Expert 7250 points
Part Number: BQ25898

Hello,

While our customer tested bq25898 STAT pin operation by using bq25898EVM, he observed STAT=Low in discharge stage. When he looked at the datasheet, it says STAT=Low in Charging in progress. Does STAT goe to Low in discharge state.

the customer test condition is connected VBUS power setting with 100mA ILIM, 300mA SYS load current shown in below.

best regards,

  • 0
    TI__Guru 57721 points

    Hi,

    Could you please share all register values?

    Thanks,

    Ning.

  • 0 in reply to Ning T
    TI__Expert 7250 points

    Thank you very much for your help. I have got a I2C register as shown in below when STAT=Low is detected.

    best regards,

  • 0 in reply to Toshiro Imi
    TI__Guru 57721 points

    Hi,

    The GUI shows the device is "Fast charging" in IINDPM. So STAT=Low is correct. The battery is discharging because of IINDPM.

    Referring to 9.2.6.2 Dynamic Power Management on the d/s, When input source is over-loaded, either the current exceeds the input current limit (IINLIM or IDPM_LIM) or the voltage falls below the input voltage limit (VINDPM). The device then reduces the charge current until the input current falls below the input current limit and the input voltage rises above the input voltage limit. When the charge current is reduced to zero, but the input source is still overloaded, the system voltage starts to drop. Once the system voltage falls below the battery voltage, the device automatically enters the Supplement Mode where the BATFET turns on and battery starts discharging so that the system is supported from both the input source and battery. During DPM mode, the status register bits VDPM_STAT (VINDPM) and/or IDPM_STAT (IINDPM) is/are set high.

    Please watch the video below for charger operations and valuable tips.

     Battery charger system overview (training.ti.com/battery-charger-system-overview

    Thanks,

    Ning.

     

  • 0 in reply to Ning T
    TI__Expert 7250 points

    thank you for your help. The customer understood "Fast Charging" in the I2C register causes the reason STAT=Low.

    best regards,