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BQ24800: Deglitch time of ACOK_DRV

Tamio Yokokura
Expert 3560 points
Part Number: BQ24800

Hi, BQ24800 support team

As for the deglitch time of ACOK_DRV, The datasheet is mentioned that

–Rising deglitch time : 1st plug-in after POR is 150msec, but the subsequent  plug-in is 150msec or 1.3sec, depending on REG0x37[12]

–Falling deglitch time : 3usec

The below is a figure created based on the description of deglitch time of ACOK_DRV. It is the situation at first plug-n.

1. Which of #1 or "2 is correct as BQ24800 design? Or, is both wrong?

And one more question

2. Is deglitch time reset whenever ACDET drops lower than VACOK_FALL?

Thanks

Tamio

  • 0
    TI__Expert 4780 points

    Hello Tamio,

    #2 is the correct representation, if the voltage falls below the VACOK_FALL value for >3us then the rising deglitch timer is reset.

    The deglitch time is reset whenever ACDET drops lower than VACOK_FALL for >3us (i.e. the falling deglitch timer). Note that the VALUE of the rising deglitch timer is 150ms on first plug in, but then defaults to 1.3s as that is the POR value of the register. It will always be 150ms the first time the adapter is plugged in, and then it follows the register value.

    Thanks,
    Khalid

  • 0 in reply to Khalid Bairuti
    TI__Expert 3560 points

    Hi, Khalid

    Thank you for your checking and advice.

    I updated my figure.

    By the way, how long does it take a time from VCC exceeds VVCC_UVLOZ_RISE until POR complete ?

    Thanks

    Tamio

  • +1 in reply to Tamio Yokokura
    TI__Expert 4780 points

    Hello Tamio,

    It is not specified in the datasheet, but it should be within a few ms. In the below plot REGN goes high very close to VIN going high (timescale is 400ms/div).

    How specific of a number are you looking for?

    Khalid