Can I power this board with 3.3V? [SOLVED]

Hi ! I’ve bought a ESP32 which looks exactly like this one (except I bought mine on Aliexpress) :

I originally bought it for a project involving batteries but that never happened so I guessed maybe I could get it to use.

WLED works fine on it and I’ve tried to power it from a 5V power supply through the USB port and I made sure both the ESP32 and the LED strip were on the same ground (had signal issues when plugged to different power sources). I’d like to embed that ESP32 into my PC, and thus power it through 3.3V from my PC PSU (because the broad dos not have a 5V pin, only a 3.3V pin) and power the LED from my PC PSU 5V.

For that, I’ve soldered a SATA cable and a cheap level shifter which uses both 3.3V and 5V power for reference. But, when I plug the SATA into a test PSU, nothing happens, even the LED strip does not light up, the ESP32 red LED does not blink. I’ve checked the PSU and it delivers both 3.3V and 5V to the SATA connector. I’m not sure what’s wrong. I thought maybe I’ve shorted the ESP32 but plugging it to my PC with a USB cable showed that the ESP is working and responding correctly. Am I getting something wrong ? Can I effectively power this ESP32 variant through its 3.3V pin ? (Yes, I’ve plugged the ground pin too…)

EDIT : It’s solved. I cannot power that ESP32 from the 3.3V pin, because it seems it’s a output… Damn I feel stupid.

Hi! Don’t feel stupid, usually it should work and I have no idea why it doesn’t either :sweat_smile:
All boards have a 5V -> 3.3V converter and the actual ESP chip runs off 3.3v, so normally this should work and just bypass that converter. Maybe this particular board has a diode or something on the 3v pin to protect it against over-voltage…

I would recommend cutting a cheap micro usb cable and wiring/soldering that up to the SATA connector. Strange design decision that there is no 5v/VIN pin on this board, I’ve seen it on just about every other board and it is super useful.