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BQ4802Y: bq4802y

CHEN YOUNG WU
Intellectual 540 points
Part Number: BQ4802Y

Why the BQ4802Y Clock is not keep clocking when system power down ?

I have setted /STOP=1 in cotrol register E and use CR2302 Li Battery for Vbc. but the clock is not continue clock while system power down.

I've checked the BVF flag in flags register D. The BVF is 1.

I need somebody to help me solve the problem.

  • 0
    TI__Genius 16845 points
    I'm not an expert with this device but I will try to help here.
    Are you observing a power fail event? Does /RST go low? What do you measure on VOUT, VBC?

    Kind regards,
    Lane Boyd
  • 0 in reply to Lane Boyd
    Intellectual 540 points
    Dear Lane Boyd :
    Thank you for your response.
    I turn off the AC power then use DC meter to measure VBC=3.03VDC, VOUT=3.03VDC also, /RST is 0VDC=GND.
    I use VOUT to power the SRAM for keeping data in SRAM while power is off. I've checked the content of SRAM they are kept.
    I also checked the VBF flag to see the VBC is valid.
    But the clock is stopped when AC power is turn off. I keep /STOP =1 forever.
    That's what I have done.
    Thank you again.

    Best regards,
    CHEN YOUNG WU
  • 0 in reply to CHEN YOUNG WU
    TI__Genius 16845 points
    Hello, sorry for the delay responding. Have you resolved the issue?

    Where is the AC power in your system? Is the device working while AC power is on?

    Kind regards,
    Lane