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BQ25886: BQ25886 with battery protection circuit

Gueston
Prodigy 90 points
Part Number: BQ25886

Hi,

For our application we use a batterypack with a protection circuit. This circuit has a cut-off voltage of about 5.6V. Can the BQ25886 handle this? For instance I see that when the battery is deeply discharged to about 4.4V, the BQ25886 performs a trickle charge and after a pre-charge. But these voltages are well below the cut-off voltage of our battery pack. Can it still perform a trickle and pre-charge in the case a battery is deeply discharged due to not using it for a longer time?

  • 0
    TI__Genius 10385 points

    Gaston,

    Will your protection circuit open when the battery falls below 5.6V? If so, you will only see the fast charge current on the battery. If this is not desired, please select a different protection circuit.

    Thanks,

    Ricardo

  • 0 in reply to Ricardo
    Prodigy 90 points

    Hi Ricardo, no it switches the batteries off. It only opens if it gets a voltage above the 5.6V threshold from the charger. So if I understand correctly, the BQ25886 won't charge this batterypack in that case?

    If not, could it be a design practice to open up the battery pack by giving it a small voltage boost of the sys output, which is 7.4V if connected to a 5V usb if I understand correctly? I could make a switch which the user can press from this output to the pack to open it. 

  • 0 in reply to Gueston
    TI__Genius 10385 points

    Gueston,

    From what you are telling me the battery pack will not charge when the battery pack is less than 5.6V because the protector will disconnect the batteries. 

    Using a momentary pulse from SYS to activate the protector to allow for charging would work, but the pulse should be as short as possible.

    I hope this resolves your issue,

    Ricardo