Power on 5V pin when switched off



  • Hi, I’m developing a sport stopwatch for curling training, based on M5Stack ESP32, gray version.

    I’ve seen that, when the ESP32 is switched off, there are inexplicably about 1.90 and 0.7 V, respectively on the 5V and 3.3V pins.
    This could be a big problem, for the fact that I need to connect the Xbee radio system, I use to riceive pulses from laser triggers, to the 5V pin and, due to this residual voltage on power pin, I risk to drain the battery for nothing.

    Can anyone help me?

    Thank you very much.
    Fabrizio



  • No one knows about tha residual voltage on power pins, when the M5Stack is OFF?
    Can anyone help me?

    Thanks



  • Hi ferrianf,

    Some days ago I asked a similar question about powering the stack.
    And until now there are no answers from the M5Stack employees. It's absolutely not understandable why those guys don't answer so important questions. And furthermore why there is no documentation about that power topic. :-(

    Anyway ... Did you take a look into the IP5306 datasheet? Maybe you can find some answers there?

    Sorry if I can help more.

    Dominik



  • Hi Dominik,
    thank you for your help.
    Unfortunately I’m not so expert to be able to read (and to understand) the IP5306 datasheet.
    I hope someone from M5Stack development team will reply to my (and to your) question.

    Thank you
    Fabrizio



  • ~1-1.5 mA will be drained from battery on 5V and/or 3.3V pins when M5Stack is off.
    I don't think you can do anything about it.
    And, due to IP5306 automatic standby after 30 seconds, you can hardly use deepsleep mode. Even if you can, the power consumption of M5Stack when in deepsleep is to high for practical usage on battery.



  • There is also some info here but due too the lack of an adequate documentation of this Chinese junk nothing can be granted. There is no up to date schematic, maybe the power management chip is controllable or not.

    Anyway, because of the support situation of M5Stack I switched in prototyping to another WROVER module board both personally and at work. Documentation is a prerequisite and not an optional extra.



  • Hi all...
    Today i do a test to my M5Stack + Lora about weird working (with external usb, all is OK, with the internal battery, the Lora is not working or working badly).
    I do not need much time to find the 2V on the 5V rail when M5 is in standby (where the lora take the power).
    Search in the datasheet of the IP5306 and i found a 50uA for standby, but nothing for the Vout problem!!!
    The only thing i see in the datasheet is the Auto Power On when Phone is inserted (the IP5306 is used for power banks)... i fear this is the problem.... I do a Test!!!
    I attached a load to the 5V rail and, voilà, M5 is turning ON!!!
    RESULT: The problem is the IP5306 itself!!!! Its a bad IC choice!!!



  • PS:
    The battery drain is not caused by the IP5306 itself, but by all the load is attached to (the 2V power the EA3036 on the main unit and the AMS1117 on the Lora)


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