ESP32 Forum

Hi everyone ,
I’m working with an ESP32-C6-DevKitC-1 and have a question about power supply options. According to the documentation, there are three (or four) ways to power the board:

• Via the USB-C port (5V)
• Via the USB-UART port (5V)
• Via the 5V pin + GND
• Via the 3.3V pin + GND

Issue:
When I power the board through the 3.3V pin + GND, the power LED lights up, but the built-in RGB LED (NeoPixel, GPIO8) cannot be controlled. However, if I supply 5V (or even 3.3V) to the 5V pin + GND, or use the USB ports, the LED works as expected.
Questions:

1. Are there known differences between powering via the 3.3V pin vs. 5V pin/USB?
   • Is the 3.3V pin handled differently internally (e.g., missing voltage regulation for certain components)?
   • Could the NeoPixel/GPIO8 be underpowered or not initialized correctly when using the 3.3V pin?
2. What is recommended for long-term or embedded use?
   • Is powering via the 5V pin (even with 3.3V!) more reliable?
   • Are there risks to supplying 3.3V to the 5V pin (e.g., for the voltage regulator)?
3. Has anyone else encountered this or have an explanation?

Background:
I plan to embed the board in a small project and am looking for the most reliable alternative to USB power, as USB ports are impractical for my final setup.

Technical Details:

• Board: ESP32-C6-DevKitC-1
• NeoPixel/RGB LED: Controlled via GPIO8 (using standard firmware/example code)
• Power source: Regulated PSU (3.3V/5V), sufficient current (>500mA)

Thanks in advance for your insights and experiences!

Hi,

The RGB LED is connected to the 5V rails. Please see the schematic for version 1.4.
If you power on the 3V3, the LED will not work, as expected.

Thanks for the hint, the schematic makes that clear.