This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

  • Resolved

[FAQ] BQ24040 and BQ2404X family Charge Complete Pin Behavior, /CHG

The BQ2404X family of charger has a charge complete pin, /CHG to indicate charge in progress or complete.  But under some conditions the battery charge has stopped (no current to battery) but /CHG indicates charge.  In other case the battery is charging (current to battery) but /CHG does not indicate charge in progress.

Best Regards,

Bill Johns,  Applications Engineer

Texas Instruments Inc

Dallas, Texas

Please click "This resolved my issue" button if this post answers your question.

For more information on Battery Charger Solutions see Link

  • This also applies to BQ21040, BQ24050, BQ24090 and BQ25100 family of devices.

    The /CHRG pin in an open drain output used to indicate that a battery charge cycle is in progress. The pin will go low when the device detects a valid power supply and starts charging the battery. The pin will go high impedance when the device detects that the battery is fully charged (Change Complete/ Termination).

    In order to optimize end user experience the charger behavior under the particular cases below is as follows:

    1.)      If TS (NTC) pin indicates an over temp condition charge is suspended, but the /CHG pin will remain low since termination or charge complete has not been detected.  Charge will resume when temp is reduced and the /CHG pin will remain low.

    2.)     The BQ2404X will automatically restart charge if after termination/charge complete the battery voltage drops to Recharge (V-RCH). This is done to maintain the battery fully charged. In this case the /CHG pin will remain low after termination even if the recharge has started.

    3.)     During OVP shutdown or Charge Timer Fault /CHG is high –Z

    Note on First Charge Cycle-- will start when power is applied, disable / enable using TS pin or detect battery insertion, /CHG is low. Start charge cycle but not First charge cycle exiting TTDM mode or battery voltage below V-RCH.

    Additional info see BQ24040 Data Sheet Charge Complete Data Sheet section 8.3.7 also see Table in section 8.4.1.

    Best Regards,

    Bill Johns,  Applications Engineer

    Texas Instruments Inc

    Dallas, Texas

    Please click "This resolved my issue" button if this post answers your question.

    For more information on Battery Charger Solutions see Link

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.