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Original question:

[FAQ] BQ25620: How does QON pin function work and what is required hold low timing?

BQ25620: How to stop power reset for QON pin?

Paul Chang
Prodigy 40 points
Part Number: BQ25620

According to the datasheet(page 16 ), the time QON is held low(about 10s) to initiate system power reset.

I want to exit from Ship Mode but i don't want to initiate system power reset.

I care user pressing the power key(QON pin) for too long, so do you have any hardware implementation in power key(QON pin)?

  • 0
    TI__Mastermind 31370 points

    Hi Paul, 

    Thank you for reaching out via E2E. 

    As mentioned in the FAQ post you attached system power reset function will also occur if QON continues to be held low after exiting from ship mode. On BQ25620 required QON held low time for this to occur will be typical 13.3 sec (0.8 sec for ship mode exit + 12.5 sec to trigger system reset event). 

    If you have concern with user pressing the key for too long you will need to add additional circuitry to release QON pin after some set time (for example 5 sec) even if end user continue to press the external button/key. 

    Best Regards,

    Garrett  

  • 0 in reply to Garrett Kreger
    Prodigy 40 points

    If i need to add additional circuitry to release QON pin and less than trigger system reset event, how to do it in additional circuitry?

  • 0 in reply to Paul Chang
    TI__Mastermind 31370 points

    Hi Paul, 

    TI has not verified and tested any specific circuit design for the function you are looking for. I can help to provide a few possible options, but I recommend you look to test this on a prototype board in your specific system. 

    A couple options include using a MCU GPIO to drive QON low for a set amount of time in response to the end user pressing a key. Alternately you can use an external FET to connect QON pin to GND when FET is on. You would need some method to turn off the gate drive automatically after a set amount of time to avoid the system reset function. 

    Best Regards,

    Garrett