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Regarding voltage regulation without an attached battery

Part Number: BQ24014

During testing of my design using the BQ24014DRC, it is often convenient (in a mechanical sense) to debug the board without the rechargeable battery attached (e.g. using the device as a passthrough LDO from 5 V USB input to 4.2 V output). I realize this is somewhat out of specification, but it works in the majority of cases. However, on some of the units produced, I believe the internal state machine is timing out somewhere and a fault condition is indicated. Usually I can clear this by loading the circuit briefly with a resistor to ground or something, however this is not a particularly elegant solution when it comes to testing production boards down the line (instead of prototypes).

Is there perhaps a better way to go about testing my design without having to have a battery plugged in?

Below is a snippet for the circuit, although It's quite close to the reference.
bq24014 implementation snippet

Best,
Alan

  • Hi Alan,

    What is the voltage on teh STAT1 and STAT2 pins when you say there is a fault condition? We'll check and see if there is something you can do to debug/test the board without a battery attached.

    Best Regards,

    Anthony Pham

  • Thanks for your reply. Immediately on plugin, a "charging" LED illuminates, so STAT1 is low and STAT2 is high. After a moment (perhaps half a second, I haven't measured this), a "finished charging" LED goes on, so STAT1 goes high and STAT2 goes low. Finally, they both go high after another half second or so, indicating the fault condition.

    I will add the following in case it's relevant. The system has a delayed start. So 50 ms after the node PBAT rises above ~2.8 V, a buck-boost converter (not shown above) initiates a soft-start that ramps up system output over 1 ms.

  • Hi Alan,

    Can you please provide some waveforms at the OUT pin from right before it goes to "finished charging" till right after when the fault is tripped?
    Can you please also provide the current and power consumption at the OUT pin?

    In the meantime, can you please try power-on reset and/or toggling the charge enable to see if that helps

    Best,
    Mira