ESP32 Forum

I'm confused about how to power either the...
1 - ESP32-DEVKITC32D by Expressif via Mouser
2 -ESP-WROOM-32 ESP32 ESP-32S Development Board by HiLetgo via Amazon

I see a 3.3 volt pin and a 5 volt pin so does it take 2 power supplies to run the chip?

a. What 3.3 volt & 5 volt power supplies do you guys suggest for powering the breadboard ?

b. How would you power a finished product that would not be plugged in during normal operation?

Thanks for any help.

Hi,

It just requires 5volts this can be either from the USB plug or direct to the "5v" pin.
It has an on-board 3.3v regulator which will then provide 3.3volts on the "3.3v" pin
(I am not 100% sure if you can power it direct from 3.3v?)

Any USB power supply is the easiest option (if you are in the U.K. poundland do a very good one for £2 which can supply 2amp).
They do tend to require a good 5volt suply though and I find when powering a finished product it is a good idea to put a good sized capacitor across the 5v near the development board to help smooth out the spikes when it is using wifi.
btw - If you ever find your esp32 is rebooting or doing weird things it is usually the power supply is the problem in my experience.

Can you power the ESP32 board via the 5 volt pin
while at the same time have the device connected to your computer via the USB?

In other words... is there isolation between the ESP32's 5 volt pin and the USB 5 volts?

Thanks for the help.

I guess you would need to check for the specific development board to be sure but I often do this with mine although I have had one blow up when I did it so probably best not to if you can avoid it.

Fran_iii wrote: ↑

Fri Apr 09, 2021 12:11 am

I'm confused about how to power either the...
1 - ESP32-DEVKITC32D by Expressif via Mouser
2 -ESP-WROOM-32 ESP32 ESP-32S Development Board by HiLetgo via Amazon

I see a 3.3 volt pin and a 5 volt pin so does it take 2 power supplies to run the chip?

a. What 3.3 volt & 5 volt power supplies do you guys suggest for powering the breadboard ?

b. How would you power a finished product that would not be plugged in during normal operation?

Thanks for any help.

No it means you can use either 5v(5v -12v it think) power supply or 3.3 volt "regulated" power supply. You cannot mix both type of the power source. Also the 3.3v power supply cannot be exceed more than 3.6 volts any time.

So, if... you are saying that...
While the ESP32 development board is connected to the computer via USB...
You can not supply 5 volts via the 5 volt pin on the ESP32 Dev Board...
That means...
If your project requires more current than the USB port on the computer can supply then you are out of luck unless you disconnect the USB...
Is that what you are saying?

I would have thought that on the dev board they would have isolated the USB 5 volts from the 5 volt pin so that which ever voltage was higher would supply the power...
All it takes is a couple of diodes...

For my project I bought two ESP32 boards...
1 - ESP32-DEVKITC32D by Espressif via Mouser
2 -ESP-WROOM-32 ESP32 ESP-32S Development Board by HiLetgo via Amazon

Looking at the Dev Board diagram here...
https://dl.espressif.com/dl/schematics/ ... v4-sch.pdf
the way I understand it...
There is a diode blocking the external 5 volts from feeding the USB 5 volts...
But if the USB 5 volts were actually higher than the external 5 volts... then the USB 5 volts would supply current to the External Power Supply.
That said... the USB 5 volt supply would have to be at least .6 volts higher than the external power supply for this to happen because of the forward voltage drop of the zener diode in the circuit.
Comments?

Please go through the article
[https://docs.espressif.com/projects/esp ... vkitc.html
Its clearly mention that

Power Supply Options
There are three mutually exclusive ways to provide power to the board:

Micro USB port, default power supply

5V / GND header pins

3V3 / GND header pins

Warning

The power supply must be provided using one and only one of the options above, otherwise the board and/or the power supply source can be damaged.

Its all what I am saying...

Ok, by what I just read, you can have 5-10v on the 5-volt pin. But you can have only 5 volts connect to your chip while it is connected to your computer or you will damage the chip and possibly your computer. I got a 12-24 volt buck converter that steps down the output to only 5 volts to run only my devices like, Relays, OLEDs, LCDs, etc. during my testing phase. Then I used it to run everything including my ESP32S. I made my boards modular so that I can remove the chip easily to replace it or to program it.