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BQ25121: System will not wake when battery attached

Dima S
Prodigy 220 points
Part Number: BQ25121

Hi,

My actions:

1. Unplug Battery

2 Plug it back.

3. System will not wake up.

My device will not turn on after I unplug battery (3.7V) and then plug back.

Only if i connect to external power (5V) , it wakes up. 

Any specific PMIC config might be causing this?

  • 0
    TI__Genius 12485 points
    Dima,

    Did the pins (PMID, /MR or VBAT) hold a voltage for long after they were unplugged?

    In the case where it does not wake up after plug in, can you press the /MR button to see if it wakes up then? I wonder if the /MR and VBAT signals were in a race.

    regards,
    gautham
  • 0 in reply to Gautham
    TI__Genius 12485 points
    Dima,

    Checking to see if you have any feedback. Also are you using the BQ25121A which is the newer version of the same IC?

    Regards,
    Gautham
  • 0 in reply to Gautham
    Prodigy 220 points

    Hi,

    I didn't get to testing, but i did checkand i  can't control /MR pin (it is floating)

    Data sheet indicates that it is pulled up all the time internally, so i guess it is high all the time.

    Is it required after inserting the battery to toggle /MR to wake system?

    P.S.

     I am Working on older version of PMIC, without the 'A'

    Thanks.

  • 0 in reply to Dima S
    TI__Genius 12485 points
    Dima,

    that is a suspicion i have. I believe you might have gotten into Ship Mode based on the slew of how VBAT came up.

    Can you try making the VBAT faster to see if you are not getting into Ship Mode?
    thanks,
    gautham