Hello,

I think I'm misunderstanding what the User Manual says about powering the STM32 from an external source. It says that if I plan to power the board with 5V, the max current of the source should be 500 mA (see table attached). What is the problem if I use a 5V source with 2A capability?

 

What is the problem if I use a 5V source with 2A capability?

No problem.

 

No problem.

That’s what I thought. I just did not understand the 500 mA max rating.

 

That’s what I thought. I just did not understand the 500 mA max rating.

My guess is that it was written by a non-English speaker and/or a non-technical technical writer who didn't have a technical proofreader.

If you want to limit maximum current in an overload situation, you use a fuse or something equivalent.

 

The note in the second picture indicates that if you are powering an external shield FROM the STM32, the max current the STM32 can supply from its on board 3V3 regulator is 500mA.
So don't try running motors or other large current addons that will be powered from the STM32 board.

And the others show what the max draw of the STM32 will be under different power supplies.
There is never any problem running a device from a power supply that can supply more current than the device needs just as long as you have the correct voltage. Just think of a car battery. Your car radio will draw just a few amps but the battery is capable of supplying some hundreds of amps for a short time.

 

What they are saying is if you intend to power the board with 5V applied to CN4 pin 4, don't try to draw more than 500mA into or off the board.
The connector contacts and PCB traces are not thick enough to handle more than 500mA.