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BQ76930: BQ7693001/BQ78350

jeremy Hall
Prodigy 20 points
Part Number: BQ76930
Other Parts Discussed in Thread: BQ78350

Tool/software:

Hi

When I use the BQ7693003 the shutdown command shuts the output and turns the 3.3V supply off

If I set autoship to on and set the time to 1 minute it shuts off after about 1 minute.  I can reactivate by taking TS1 high.  All good.

We are trying to use the BQ7693001 which gives 2.5V at reg out, the advantage being that a wasteful 3.3V to 2.5V regulator is not required.

Unfortunately when I hit the shutdown button with this version, the output does indeed shut down but the 2.5V supply from the BQ7693001 remains on along with the fuel gauge LED etc taking more current than I want and it can only be reactivated by clicking reset, TS1 has no effect.

Auto ship mode does not work at all.

HELP!!!!

  • 0
    TI__Genius 9365 points

    Hello Jeremy,

    Do you mind checking the voltage at the CAP 1 pin when you hit the shutdown button? This should be 0V if the device is OFF. All output voltages should be off when the bq769x0 is shutdown. 

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Prodigy 20 points

    Hi Alexis

    Thank you for replying

    The cap 1 pin is at 3.2V before pressing shutdown and stays at 3.2V when the output from the Protection control board cuts.  The reg out 2.5V output keeps everything running thereafter permanently and Cap 1 pin7 remains at 3,2V.

    I should add that the previous version of our battery used a BQ78350 R1 chip in conjunction with a BQ7693003 and the new one uses the BQ78350 R1A version with a BQ7693001.

    Best rgds

    Jeremy

  • 0 in reply to Alexis_H
    Prodigy 20 points

    As a further thought

    The original combination of 7693003 and 78350 R1 worked reasonably well although shutdown and autoship could be erratic.

    My understanding is that the R1A version was introduced to improve this.

    I tried another combination fitting a 7693003 from an old board in conjunction with a 78350 R1A.  This worked better but shutdown does not work properly until long after a reset has been carried out.  Performing another reset recreates the problem for an hour or so.

  • 0 in reply to jeremy Hall
    TI__Mastermind 38400 points

    Hello Jeremy,

    If CAP1 remains at 3.2V, the part did not enter SHIP/SHUTDOWN mode. So the SHUTDOWN commands may have not properly be sent. 

    I will loop in the gauging team so they can support you with the BQ78350.

    Best Regards,

    Luis Hernandez Salomon

  • 0 in reply to Luis H. S.
    TI__Mastermind 38400 points

    Hello Jeremy,

    Do you have logic analyzer captures of the I2C lines when sending the commands?

    Best Regards,

    Luis Hernandez Salomon

  • 0 in reply to Luis H. S.
    Prodigy 20 points

    Hi Luis

    We are lucky to have a scope!!!

    No I am sorry I can't provide that but thank you