ESP32 Forum

Hello all,

I have an ESP32-CAM which works perfectly fine on 3.3V, but as soon as I switch to 5V, the same program will not work.

Serial output is garbage and oddly the lamp is flashing which does not occur on 3.3V. I even loaded an empty sketch so I don’t think the Wifi startup is the issue. I've tried multiple different 5V sources (FTDI, Arduino, LIPO) so I don't believe the power supply is the issue.

Is there something I'm missing that I need to change to run on 5V? I'm simply connected to the 5V pin and GnD instead of 3.3V pin and GnD.

Everything on the board runs from the 3.3V rail. There are 2.8V and 1.2V rails but these are derived from the 3.3V rail.

The only thing the 5V connection does is connect to a 1117 linear regulator to provide the 3.3V.

So if the board works fine when fed directly from 3.3V then there seems to be only two possibilities for the problem with 5V. Either the regulator is bad or the 5V supply current / voltage is insufficient to give a good 3.3V output from the 1117 regulator.

The current drawn by the board is reasonably high so it is important that any 5V source can supply this current while maintaining the input voltage to the 1117. This regulator is not really a LDO (low drop out) and requires at least 4.5V to give 3.3V out.

A LIPO is not going to work (V < 4.2V). Many USB port 5V supplies and FTDI will struggle to provide the sufficient current.

Your best bet is to test with a known solid 5V supply which can supply at least 1A without dropping its voltage output. Also it is important to keep the connections low resistance. Going through a solderless breadboard for example can introduce significant resistance.

Maybe a bit late but I had the same issue and solved it by raising the input voltage, beginning with 3.3V,
around 4V it connected to wifi and works fine.