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BQ77915: Support for 2s2p Battery Configurations

Marc Nadeau1
Prodigy 20 points
Part Number: BQ77915

Is there any technical reason as to why the BQ77915 can't be used to protect/manage 2s battery configurations?  I was hoping to use this device with a 2s2p LiPo battery pack.

  • 0
    TI__Expert 7465 points

    Hi Marc,

    The BQ77915 is only equipped for 3-5S battery packs. We do have some 2S protectors, but they do not include all of the features of the BQ77915. Here are some of our datasheets for 2S protectors:

    http://www.ti.com/lit/ds/symlink/bq2962.pdf

    http://www.ti.com/lit/ds/symlink/bq29209.pdf

    http://www.ti.com/lit/ds/symlink/bq294502.pdf

  • 0 in reply to Shawn Hinkle
    Prodigy 20 points

    Hi Shawn,  Thanks for the response.  Understand that the datasheet claims 3-5s but looking at the schematics, internal block diagram, etc. It is not clear to me as to the technical reasons behind this minimum cell count limitation.  What issues could one expect if the chip was operated in a  2s vs. 3s config?  Would some protection/charging features not work & if not which ones?  I'm assuming that there was some technical reason behind why the designers chose a 3s minimum vs. 2s or even 1s.  There is a circuit limitation that I guess I don't understand.  Thanks for your help.

  • 0 in reply to Marc Nadeau1
    TI__Expert 7465 points

    Hi Marc,

    The chip is designed to work with a minimum of 3 cells. The CCFG pin is used to configure the device for 3, 4 or 5 cells. There is no option to configure it for 2S. If only 2 cells were connected, it is very likely the device would not work at all. I have not tried the configuration myself, but I assume the device would detect and under voltage condition on the VC3 pin and would not recover until 3 cells with safe voltages were connected. I highly recommend using a device that is properly suited for the cell count you are using.