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Original question:

BQ76952: Potential current loop inside BQ76952

BQ76952: potential current loop within BQ76952

Anandteerth Wadavi
Prodigy 105 points
Part Number: BQ76952


Dear Luis, In reference to potential current loop within BQ76952, there shall be serious problems as the Device works even if the VSS is floating. Also, the current measurements at both the polarities differ to great extant. What is the way to avoid internal current loops within BQ76952 ? Thanks

  • 0
    TI__Mastermind 42060 points

    Hello Anandteerth,

    The best way would be to not have a load connected while the cells are being connected, since it does seem the device has no protection FETs. Usually the FETs would be OFF during initial cell connection, so there is no risk of current flow when connecting the cells.

    Are you seeing issues when connecting the cells? Could you describe it in more detail?

    Best Regards,

    Luis Hernandez Salomon

  • 0 in reply to Luis H. S.
    Prodigy 105 points

    Dear Luis,

    The test set up is like this - There is no load connected and Auto cell balancing is enabled through OTP in CMU. Now, when powered up with a connector connecting all the 16 cells almost at the same time, the return path latches to upper cells and currents measured through cell zero is much lower than what is flowing through top cell.

  • 0 in reply to Anandteerth Wadavi
    TI__Mastermind 42060 points

    Hello Anand,

    I don't quite understand. Let me rephrase to see if I understand correctly. All cells are connected and cell balancing is enabled, when cell balancing is enabled you see higher current through the top cell, is this correct?

    You also mention that the part powers up after connecting the cells, typically you have to apply a voltage to the LD pin or pull TS2 low to power the device. I assume one of these conditions is always met.

    Best Regards,

    Luis Hernandez Salomon