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BQ29700EVM-610: Problem with the battery protection

Tom More
Prodigy 190 points
Part Number: BQ29700EVM-610

Dear TI forum,

I'm Tom and I'm new in this forum, hi everyone!

I have now a problem with the battery and his protection :(

I design the follow circuit to protect the battery for my application

The problem is when I plug the battery nothing happens, no voltage flow, but if I touch the VBAT- with GND of my PCB for a instant, the voltage is OK all the time, the current flow and the battery works properly

Any idea are welcome!

Thanks!

Here are the picture of my design

  • 0
    TI__Mastermind 19580 points
    Hi Tom,

    Welcome to E2E.

    In regards do your question. The bq29700 is in "sleep mode" when it is connected to a battery without a load. The lack of load causes the V- pin to be floating. The bq29700 wakes up and has normal operation when it has a voltage across BAT and VSS (battery voltage) and V- is close to VSS.

    A load wakes up the device because it applies a charge voltage which lowers the voltage at V- to a voltage close to VSS-. Also by shorting the device, you cause V- and VSS to be equal which turns on the device.

    Best Regards,
    MZ
  • 0
    TI__Expert 6085 points
    The power-down state is released when a charger is connected, and the voltage ( V- - BAT) > 1.3V. please refer to the d/s 9.4.3