Both USB and ESC power options

motor controllerusb

I am working on a flight control board inspired in this Sparkfun board:

http://cdn.sparkfun.com/datasheets/Dev/Arduino/Boards/RedBoard-v21.pdf

It is basically an Arduino UNO with a FTDI chip instead Atmega8u2 as USB-UART bridge. It manages power stage in order to allow both USB and Jack connector at same time. In my device I want to allow both USB and ESC power options. My question is, can I replace the Jack connector and the LDO and just connect the 5V output of my ESC in the 5V wires of that schematic?

Something like this:

Schematic

I actually don't know how smooth ESC's output voltage is. Maybe it is a good idea to let the LDO and connect the ESC over the jack input.

Best Answer

Given that the 5V supplies are feeding a 3V3 LDO, then why not just use two Schottky diodes.

Put one in series with each supply. That will allow both to work, and the higher voltage will 'win'. Schottky diodes will only drop 0.1-0.2V in conduction.

Here is a 2A one I use often: http://www.digikey.com.au/product-detail/en/CDBB2100-G/641-1109-1-ND/1559070

Related Topic