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BQ24195: Power source prioritization

Part Number: BQ24195

Hi I have a question regarding the bq24195 that is not clear to me. With this IC I can power my system using either battery or external DC power right?
Is there a prioritization between the power sources? For example when the DC source is connected, the battery serves a back-up role?
In case of power failure of the external DC source, the system toggles automatecally to battery operation and remains functional?


  • Nick,

    In general, when valid VBUS is present, VBUS will support both SYS load and battery charging. Please refer to Narrow VDC Architecture on the d/s for the details.

    If only battery is present and the voltage is above depletion threshold (VBAT_DPL_RISE), the BATFET turns on and connects battery to system. Please refer to 8.3.2 Device Power Up from Battery without Input Source on the d/s for the details.

    The charger operations are complicated. It is highly recommended to get familiar with the charger operations by testing the device EVM before making customized designs.



  • Thanks for your reply Ning,
    Sorry for the confusion, my question is related to source prioritization. When both sources are connected, the battery on BAT and the external adapter on VBUS, then which source supplies the system, the battery or the external adapter?

    When both sources are connected and for any reason the DC adapter disconnect, then the system will remain powered on from the battery?

  • What I need is an IC the supports:

    1. External dc source (primary source)

    2. Battery source

    3. Battery charger

    When the primary source is connected, should supply the system from the main source (primary source prioritization)

    When the primary source disconnects, the system remains on and is supplied from the battery.

    When the primary source connects, the system voltage toggles to the primary source

    Can I achieve that functionality with BQ24195 or, should I look for another IC?

  • Hi,

    The BQ24195 may achieve the functions you describes basically if the input power @ VBUS is high enough to support both the SYS load and battery charging power.

    If the input power is not high enough, DPM may be triggered. Please refer o Dynamic Power Management for the details.



  • Thank you Ning!!