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Original question:

BQ24610: BQ24610

BQ24610: BQ24610 LED CHARGE NOT OFF WITHOUT AC/DC ADAPTER INPUT

Bang Duong
Prodigy 110 points

Part Number: BQ24610
Other Parts Discussed in Thread: BQ40Z50

Tool/software:

Hi guys,

I'm using BQ24610 with BQ40Z50RSMT-R1 for Battery Management. When I plug the AC/DC adapter input, BQ24610 is charging and the red LED is light, which means STAT1 is on, STAT2 off.

When I unplug the AC/DC adapter, the red LED is still on, which means STAT1 is still on.

 I attracted schematic. So please help me resolve this problem. 

Many thanks,

2860.[03] - BATTERY CHARGER & MONITOR.pdf

  • 0
    TI__Mastermind 41551 points

    Hello Bang,

    Can you provide a scope capture of STAT1 and PVCC when this issue occurs?

    Does STAT1 eventually shut off?

    Best Regards,

    Christian

  • 0 in reply to Christian Moyer
    Prodigy 110 points

    Hi Christian,

    I do not have a scope, but when I unplug the AC adapter, PVCC is 12V, the same as battey voltage. The voltage at the STAT1 pin is approximately 0 V. When I do not connect the battery, the voltage at the STAT1 is about 23V.

    I don’t understand why the BQ24610 IC doesn’t detect that the charging source has been removed and still indicates a charging state.

    Thanks,

  • 0 in reply to Bang Duong
    TI__Mastermind 41551 points

    Hello Bang,

    Do you see any difference, if you move the pull up resistor to the other side of the back-to-back fets?

    Best Regards,

    Christian.

  • 0 in reply to Christian Moyer
    Prodigy 110 points

    Hello Christian,

    I tried. I use an Adapter power supply for the LED, but still the same. When I unplug the adapter, the LED STAT1 is still on, but the light is dimmer when I plug it back in. Can you take a look at the schematic I sent to see if there’s anything unusual?

    Thanks,

  • 0 in reply to Bang Duong
    TI__Mastermind 41551 points

    Hello Bang,

    I don't see any obvious issues with the schematic.

    Does STAT1 eventually shut off?

    Can you measure the input voltage when adapter is removed? The Q1 FET should block the STAT1 pull up rail.

    Best Regards,

    Christian.

  • 0 in reply to Christian Moyer
    Prodigy 110 points

    Hello Christian,

    STAT1 is always on, and it only turns off when the battery is disconnected from the circuit.
    The adapter voltage is equal to the battery voltage.

    I also know that when the external power source is removed, STAT1 should not turn on, so there shouldn’t be any current flowing to light up the LED.
    However, in reality, when I checked the registers of the BQ40Z50, the battery was discharging at 22 mA — which matches the current flowing through the LED.

    Thanks,

    Bang Duong

  • +1 in reply to Bang Duong
    TI__Mastermind 41551 points

    Hello Bang,

    What is the ACDRV voltage when this behavior is occuring?

    The back-to back fets should be blocking the battery voltage from the adapter voltage.

    Can you confirm these are not damages?

    Best Regards,

    Christian.