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BQ24610: About the output power from the battery when there is AC adaptor.

Kengo.Y
Guru 11245 points
Part Number: BQ24610

Hi team,

There are times when my customer wants to prioritize power supply from the battery.
How can we block input power when it is available?


Can the CEpin turn off the ACDRVpin?
Please let me know if it can be configured with peripheral circuits.

Sincerely.
Kengo.

  • 0
    TI__Mastermind 40325 points

    Dear Kengo,

    Help me to understand why you would want to block input power when it is available? By doing this you will drain your battery and it will be more depleted when the input power is removed. The power path scheme prioritizes system current from the input, only drawing from the battery in the absence of the input. This conserves the battery energy.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • 0 in reply to Michael Emanuel35
    Guru 11245 points

    Hi Mike,

    Thank you for your reply.

    Because the input power supply is also a battery, it needs to be switched.
    I have summarized what my customer wants to do.
    Could you confirm this?

    bq2416x Powered from battery with adaptor connected.pdf

    Sincerely.
    Kengo.

  • +1 in reply to Kengo.Y
    TI__Mastermind 40325 points

    Dear Kengo,

    The datasheet says, "If VCC is below the UVLO threshold, the device is disabled, ACFET turns off and BATFET turns on." This is the solution you are looking for.

    You would need to disconnect the VCC pin from the input. As shown however, you would need to drop VCC below the UVLO threshold. The typical "Adapter supply current (current into VCC, ACP, ACN pin)" is 25 mA when charging and when VCC>VSRN. Using I=C*dV/dT, this would discharge the capacitor from say 15 V to 3.85 V (UVLO) in dT = C*dV/I or dT = 1e-6* 11.15/0.025 = 446 us. These are rough calculations and assumes the full discharge goes into the VCC pin. Please note it is only a sample calculation. Please validate that you can discharge the VCC pin  in a timely manner.

    Please ensure you can discharge the VCC pin to below UVLO. In addition, please make sure the resistor, capacitor, and chosen FET for the VCC pin can handle the current generated when FET is closed. This will happen when you reconnect the input to VCC.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answers your question.