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BQ27421 Communication Freeze

Guillaume Tiffineau
Prodigy 70 points

Hello,

I'm using a BQ27421 in my design.

Sometimes the communication completly freeze until the battery is completly empty.

I didn't find any solution for this issue and it becomes critical.

Can you help me please?

The charging current is limited to 300mA, the max charging voltage is 4.2V.

Regards,


Guillaume Tiffineau

  • 0
    TI__Guru* 76230 points
    Hi Guillaume,
    How often does this happen? Is it easy to reproduce? Can you share your schematic and layout files with us? I have sent you a fried invite that will enable us share files privately.
    thanksOnyx
  • 0
    TI__Mastermind 24870 points
    Hello Guillaume,

    To add to my colleague Onyx, could you please clarify what it means when you say:

    "Sometimes the communication completely freeze until the battery is completely empty"

    Does this mean the device recovers once the battery is at a certain voltage? Or the device is reset because the battery falls below the minimum operating voltage of the device? Or do you remove and re-plug in the battery? Or you start a charge, but kept the battery plugged in and the bq27421 comes out of the freeze state?

    Thanks,
    Kang Kang
  • 0 in reply to Kang Kang
    Prodigy 70 points

    Hello,

    Thank you for your answer.

    The communication recover when the battery voltage drop under a certain voltage (I don't really know what is this voltage because my Microcontroler can't work à this voltage) 

    The battery is the only source of power.

    The problems comes without any reason. I didn't identified the way to reproduce the freeze.

    Did you ever heard a problem like that ?

    Is there a way to do a reboot of the gauge ? (Except by the RESET instruction)

    Regards,

    Guillaume Tiffineau

  • 0 in reply to Guillaume Tiffineau
    TI__Guru* 76230 points
    Hi Guillame,
    I responded to your email, but for the purposes of helping others who might run into a similar problem, i will post a similar responce on here.
    Check your schematic to make sure you have decoupling caps as shown in the EVM schematic on Vdd and BAT pins. Make sure these caps are on the same side of the IC and are close the pins as possible.
    Also make sure you have a 10K resistor connected from BIN to VSS.
    When this freeze occurs do you see ITPOR bit getting set. If it is, it means your device is some how getting reset. In response to your question about reboot, a POR or comand 43 resets the gauge.
    thanksOnyx