I am working on a brushed motor quadcopter. It is powered by a 3.7V LiPo Battery. I have an ESP32 microcontroller which sends PPM signal to a SP Racing F3 EVO Brushed flight controller. The 3.3V to the ESP32 are provided by a LDO regulator(MCP-1700-330) and the flight controller board is powered directly by the same battery. The issue I am facing is that when the brushed coreless motors start running the ESP32 resets(via Brownout Detection). I read similar threads which suggested using large valued capacitors at the regulator input/output else using separate power supplies. In my case I did try large capacitors(470uF) at the input of the regulator but the ESP32 still reseted. And it is not possible for me to use a separate power supply. Please help me as to how I may solve the issue.


1 Answer 1


You must make sure that the motors do not drain your capacitor. Try adding a (Schottky) diode before the LDO and put the capacitor after the diode and before the LDO:


simulate this circuit – Schematic created using CircuitLab

  • 1
    \$\begingroup\$ I tried a Schottky diode (BAT85) and a cap(470u) in the configuration you suggested. Now no reset occurs when the motors spin till 50% duty cycle(PWM) but beyond it the controller resets. What may I do? Will increasing capacitance work? \$\endgroup\$
    – Soham
    Mar 25, 2020 at 6:57
  • \$\begingroup\$ You could try but you might have an inherent power problem. Meaning there may be no simple solution. \$\endgroup\$
    – Oldfart
    Mar 25, 2020 at 20:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.