LoPy with 3.3V direct powering fails to start.

  • @robert-hh

    Hi Robert, thanks for the answers.

    We have tested LoPy in both voltage supply configurations.

    WiFi does not start when powered at 3.3V.
    When powered with 5V WiFi starts.

    This is a big issue.

    There is something wrong with the switching circuit If it is not able to provide enough power to WiFI with 3.3V and 1A available on 3V3 pin.

  • @cocoa You should be able to power LoPy through the Vin Pin with 3.3V. At that voltage, the 3.3V regulator set's itself to bypass mode. It does not matter when the Vcc for the ESP32 is a little bit less than 3.3V. The ESP32 runs well down to 2.8 V.

  • @ssmith

    Hello, yes, you are right, it warms up when supplied with 3.3V.

    So there is an issue with LoPy's switching regulator.

    Waiting for an answer from Pycom's guys about this issue. (I hope in @daniel )

    If is not possible to power it at 3.3V ...

    @Fred wrote in this post : https://forum.pycom.io/topic/1022/root-causes-of-high-deep-sleep-current

    "Power the board via the 3V3 pin using a stable 3V3 supply that is able to deliver at least 400mA. This lowers the deep-sleep current to around 2.5mA."

    @Fred in which way you were able to power the board without warming up it or worst, without kill it ?

    I hope in an answer with a workaround from pycom engineers.

  • When you power it from 3.3V, place your finger on the area beside the LED, opposite of the reset switch to see if the power supply chip is heating up. I burned up 2 LoPy devices trying this.

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