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BQ25120A: /MR push-button not work well. INT pin has no 128us pluse,after /MR button pushed.

user4529782
Prodigy 40 points
Part Number: BQ25120A
Other Parts Discussed in Thread: BQ25120

Hi all,

We have a very serious problem when using BQ25120A.

Our product is mass production. so this problem is very serious.

We use key button with /MR pin as power and OK key. Some customers find /MR key is no function after product being standby mode for a long time (one or two weeks ,for example).

If put charger on ,the problem will be recovery. If not ,the problem will be exist forever.

We got issue product and test it.  INT pin has no 128us pluse,after /MR button pushed.

We want to know why and how to fix it ,Help plz.

  • 0 in reply to user4529782
    TI__Genius 12485 points

    hello user, 

    I just got back from a work trip but I replied to my local field account FAE today who is helping you on this. 

    Here is the response anyways. 

    ------------------------------

    Here are the steps to process when /INT is issued.

     

    1. When /CD is low, the wake timers will only start counting when /MR push button is pressed.

    2. When Wake1 or Wake 2 is met, you will get the interrupt the first time. Then you will have to bring /CD pin high and read all the registers to prepare for the next wake timer event.

     

    Below is a sequence I did- (matches the scope below)

     

    • A – Power up with battery only
    • B - /MR pressed and wake1 timer expired
    • C - /MR pressed longer and wake2 timer expired
    • D - /CD pulled high
    • E- I2C read all the registers
    • F- /MR pressed and wake1 timer works normally.

     

    So in summary you will need to raise /CD pin and then read all the registers to count wake timers back again.

     

    Let me know if you have any questions.

  • 0 in reply to Gautham
    Prodigy 40 points
    Dear Sir,
    Thanks for your reply.

    We use this sequence ,so normal status sample there are wake1 INTs exist. But abnormal status sample from users, there are NOT wake1 INTs detected. After connect charger to abnormal status sample, the INTs recover to right status.

    This issue is random , we don't know exact method to reappear it now.
    We put 28 sample in standby mode (bq25120 in battery high impedance mode)trying to reappear it , and 5 days past , the samples are ok.

    Local FAE make sure that there is no INT signal in high impedance mode, suggest us to set reg0x03 bit 0 and test it.
  • 0 in reply to user4529782
    Prodigy 40 points

    We tried to write 1 to bit0 of reg0x03, but this reg value didn't change in battery mode. It could be set 1 in charging mode, and would set to 0 auto when charger unplugged.