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BQ24725A: Disable the power source from battery

Jacob Bai
Prodigy 25 points
Part Number: BQ24725A


Hi, there

I am using bq24725a with Linux on iMX processors, just wondering is it possible to disable the power source from battery (BATDRV) without adaptor plugging in?

From the datasheet, I only found that we can switch power source if there is adapter detected. I am trying to read the battery voltage and turn it off if the voltage is lower than some level, even if there no adapter attached.

Also, the LEARN mode is not working as expected. The power source got switched from battery to adapter if I plug in the adapter, but the battery level is higher than 70% which is the battery depletion threshold I set. Is it suppose to continue using the battery power source until the voltage lower than 70%?


Regards,
Jacob

  • +1
    TI__Genius 11850 points

    Hi Jacob,

     

    When the adapter is not present, then the BATFET stays on so that the battery can power the system load. The BQ24725A does not have an option to manually turn off the BATFET in this case.

     

    Regarding the device exiting LEARN mode after the adapter is removed and plugged back in, this is likely due to ACDET falling below 0.6 V when the adapter is removed. Note that ACDET must be above 0.6 V for SMBus communication to be active. When you remove the adapter and plug it back in, the register settings are reset to the default POR values, so LEARN mode is disabled.

     

    Best regards,

    Angelo

  • 0
    Prodigy 25 points

    Hi Angelo,

    Thanks for your reply.

    Can I set up a threshold for the battery level, if the battery level below that threshold, it will turn off the battery to save the battery even AC is not there?

    Regards,

    Jacob

  • 0 in reply to Jacob Bai
    TI__Genius 11850 points

    Hi Jacob,

     

    The battery over-discharge protection will need to be controlled externally. Many battery packs come with a protector circuit which will open and disconnect the battery from the load when the battery voltage is too low. If your battery pack does not have this, then please take a look at TI's battery protector ICs below. If you have questions about battery protector ICs, then please create a new E2E thread with the part number in the title so that the battery protector team can support your questions.

    https://www.ti.com/power-management/battery-management/protectors/overview.html

     

    Best regards,

    Angelo