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BQ24004: Use BQ24004 to charge 2 Lithium Ion rechargeable batteries

Jin Jiang
Intellectual 310 points
Part Number: BQ24004
Other Parts Discussed in Thread: BQ24125, BQ24130, BQ24113A, BQ24040

Dear Sir/Madam,

I plan to have two Lithium ion battery in serial so that I have a higher supply voltage to boost to 24V. Should I use battery charging controller like BQ24004 that can work with 2 cells or to use two 1 cell controller? It seems to me that 2 cell battery charging controller is not so common. There are only 138 BQ24004 on digikey at this moment and no stock for other options.

Thanks.

Jin

\\atlas2\Engineering\ELECTRONICS\Schematic and PCB\Altium Projects\Base Station Dongle Rev2
  • 0
    TI__Guru 68836 points
    Hello
    The bq24004 is still and active part but it is an older devices released in 2000. Input voltage is 8.4V to 10V which is not a common adapter.
    If two 1 cell units are used it may be possible to use a common 5V adapter in your application.
  • 0 in reply to Bill Johns
    Intellectual 310 points
    Bill,
    Thank you for your quick response. Can you share part number/schematic for the solution you mentioned "to use a common 5V adapter" Does this solution use a TI IC?
    I found another IC BQ2057WSNTR, does this IC design to handle two lithium ion/lithium polymer rechargeable battery serial together?

    Thanks.

    Jin
  • 0 in reply to Jin Jiang
    TI__Guru 68836 points
    Have you look at switch mode chargers such as BQ24130, BQ24113A or bq24125?

    The bq2057W is a linear regulator like the bq24004, but the device requires and external pass transistor and sense resistor. Yes it will support two series cells.

    For a simple single cell linear charger take a look at bq24040, very low external parts count. This would be a 5V input.

    You may have tried to post more info I see the below link.

    \\atlas2\Engineering\ELECTRONICS\Schematic and PCB\Altium Projects\Base Station Dongle Rev2
  • 0 in reply to Bill Johns
    Intellectual 310 points
    Bill,
    Thank you for the reply. Guess general LDO or switching mode DC/DC advantage/disadvantage apply here. When it is battery charging controller, anything specific to consider when choosing between LDO based battery charging controller with switching mode charging controller?
    The line of text was by mistake, please ignore.
    Best.
    Jin
  • 0 in reply to Jin Jiang
    TI__Guru 68836 points
    Hi Jin
    As a general rule a linear charger (LDO based) will work well if the current is low and voltage drop across the device is low. Typical charge currents are less than 1A and prefect for 500mA or less. Voltage drop across the device 2V to 3V, many devices are designed to work with USB input.
    Switching chargers can support a broad range of input voltages and mult cells.