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BQ25600: BQ25600YFFR

Leila Fu
Prodigy 10 points
Part Number: BQ25600

Tool/software:

After our product has been turned on and placed for two days, it enters a shutdown state, and the battery discharges to below 2.85V, making it impossible to charge with the charger. When the USB is inserted, there is a normal charging state of 1-2 seconds where VPH rises from 2.8V to 3.65V. The machine attempts to turn on for 2-23 seconds, and the battery has a current output of 0-300mA. VPH drops to 2.8V, and the charging state is unclear. The SW has a switch signal, but the frequency is only 1.3K. After 23.15S, the battery's output current suddenly jumps to 0mA, and it remains at 0-2mA output for the rest of the time. If the USB is unplugged and plugged in at this time, the battery still remains at 0-2mA output. If the battery is disconnected from the motherboard and reconnected, the above process will repeat, with 1-2 seconds of charging, 2-23s of unclear charging state, and 0-2mAs output for the rest of time. When the battery voltage is ≥ 3.0V, the charger will repeat the above 0-23s action, and start charging at 24s with VPH rising to 3.6V.

  • 0
    TI__Mastermind 40925 points

    Hello,

    Can you please send a schematic and a register dump when this is happening? Does the battery have a protector?

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 10 points

    Fullscreen Register after power up.txt Download
    1
    2
    3
    0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
    00: 04 1a 86 10 98 8f 65 4c 34 03 80 01 ff ff ff ff ??????eL4???????
    10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ??????????????
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

  • 0 in reply to Leila Fu
    TI__Mastermind 40925 points

    Hello,

    Have you tried an ABA swap? This is where you take the bad unit and put it on a good board, and a good unit and put it on a bad board. This could provide valuable information.

    I noticed that the PG pin is tied with 0 Ohm to CBL_PWR_N. Is there a 10k pullup? I think the device could be damaged by shorting the pull up rail to the open drain of PG/. Please insert the 10k pullup and let me know the result.

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 10 points

    Hi,

    Every board have this problem. There is no 10K pullup tied to PG. I will insert the 10K pullup.

    Regards,

    Leila

  • 0 in reply to Michael Emanuel35
    Prodigy 10 points

    Insert 10Kpullup，no change. 

  • 0 in reply to Leila Fu
    TI__Mastermind 40925 points

    Hello,

    Please start with a fresh board, insert the 10k pullup, then and only then turn on the board. What is the pullup voltage on that pin?

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    Prodigy 10 points

    Hello

    Hello，

       When USB is pluged, VPH is below 3.0V and LDO does not work. The voltage of pullup 10k  is 0V. Why are you want to test a fresh board?  And I want to know the principle of inserting 10k pullup into PG.

    Thanks

    Leila

  • 0 in reply to Leila Fu
    Prodigy 10 points

    IS there a way to determine whether Q4 is closed or open? Thanks.

  • 0 in reply to Leila Fu
    TI__Mastermind 40925 points

    Hello,

    When the PG pullup is connected, if there is not a 10k resistor, it shorts GND to the pullup which could damage the device. I want a fresh board tested because I think every non-working board is already damaged. Please try with a new board with the 10k pullup attached.

    Regards,

    Mike Emanuel

  • 0 in reply to Michael Emanuel35
    TI__Mastermind 40925 points

    If no input is attached and battery is applied, Q4 should be closed if there is SYS voltage.

  • 0 in reply to Michael Emanuel35
    Prodigy 10 points

    Hello 

    This is DVT board with the problem. And we have already made a version of the evt board without this problem. The schematic of two versions are same. The  PG of  EVT also has no pullup resistance. The difference between two versions is PCB routing. So I think some routing difference cause BQ25600 some error. And I can't get any information from UART log, don't know the register about some mistakes when usb is pluging.

    Thanks

  • 0 in reply to Michael Emanuel35
    Prodigy 10 points

    I can't  understand this sentence. If no input is attached and battery is applied, Q4 should be closed if there is SYS voltage. Why Q4 should be closed?  When board power up and USB is not attached, there should be power supplied to the SYS.

    Q4 has been closed. what is the state of SYS voltage. Does the current flow from the battery to the SYS pass through Q4? When the battery is charging, is the current still passing through Q4? Q4 is bidirectional MOSFET? 

  • 0 in reply to Leila Fu
    TI__Mastermind 40925 points

    Hello,

    Glad you were able to figure it out. Please make sure all open drain connections are pulled up with 10k to avoid damage.

    Q4 being closed means the BATFET conducts and the System is connected to Battery in Battery only mode. During charging, current flows from System to Battery through BATFET. During discharge and supplement, current flows from Battery to System through the BATFET. 

    Regards,

    Mike Emanuel