ADC doesn't work when measuring a battery voltage which powers up the whole system using Lopy



  • Hi,
    Can someone please advice me, I'm stuck!

    I use a 4.2V lithium battery which goes to a boost converter to step up to 5V and powers up the PYCOM.

    I also have a battery connected to the potential divider and opamp follower to provide 1V maximum voltage.

    This voltage then goes to PYCOM (ESP32 IC) Lopy4 ADC pin to measure the voltage reading.

    I found that ADC works when the battery is not powering up the system (using external power suppy). But ADC doesnt work (gives falls readings and maxed out) when the battery is providing a power supply to the step up to the PYCOM. I use an opamp to sort out the impedance. I don't know what else to do! Can we actually measure a battery voltage when its powering up the PYCOM?

    Thanks!
    Emilija



  • @emilija-zuk Did you take the internal pin protection diodes into account when designing the circuit?



  • @emilija-zuk How do you connect the battery to the Pycom device?


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