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BQ24109: Would BQ24109 charge 0V battery?

Part Number: BQ24109
Other Parts Discussed in Thread: BQ40Z50-R1, BQ25886, BQ25306

Hello Sir:

Can you help to check would BQ24109 charge 0V battery?

I mean, sometimes TI gauge (BQ40z50-R1 or others) enters UVP protection, which DFET turn off.

If charger has battery detect function, that charger can not charge the battery (with BQ40z50-R1).

Please let us know your recommendations.

Thanks a lot.

  • Hi Statham,

    To disable battery detection, a large capacitor (e.g.>250uF) should be placed on the OUT pin as computed in datasheet section 8.3.16.1 Battery Detection Example.

    Regards,

    Jeff

  • Hi Jeff:

    Can you help to recommend a 8.4V/0.8A charger?

    And it should be charged 0V battery.

    Please help to provide your recommendations.

    Thanks a lot.

  • Hi Statham,

    For those chargers with battery detect, like BQ24109, you will need to defeat the battery detection by additional output capacitance.  Chargers without battery detect provide a trickle charge in the 100mA range until the battery voltage gets above a certain value, usually some multiple of 2.4V. So, charge time from 0V to 2.4V can be long. 

    If your input voltage is 5V, then I recommend BQ25886 boost only charger.

    If your input voltage is > 8.4V, then I recommend BQ25306.

    Regards,

    Jeff