Efficiently convert DC 12V/3A to 5V

Other Hardware Motors, Mechanics, Power and CNC
1

Hi!

I want to build a setup which gets its power from a wall-mount power supply delivering up to DC 12V/3A.
For safety reasons I don't want to have mains power in my device.

In my "box" there is a Raspberry PI 3 with Touch Display and an Arduino Uno with approx. 40 standard 5mm LEDs and some potentiometers.

According to the manufacturer the Pi needs 5V/2.5A, the display something like 600mA and the Arduino+components definitely below 1A.

Standard linear regulators are useless, because they transform the 12V-5V=7V into heat, so I loose most of the juice coming from the wall plug.

So my idea was to run 2 LM2596 step down converters in parallel and have the first one power the Pi and the second one power the rest (display+Arduino stuff). From what I learned these types of ICs are converting the voltage in a much more efficient way.

Would this work? Is it possible to have 2x 5V/3A or at least 2x 5V/2.5A out of a single 12V/3A source?

2

If you have 36W (12V x 3A) from the source you can get around 90% of that out if you use a good switch-mode DC-DC converter. 30W should be fine. But they are not easy to design so it's probably better to buy. EBay is full of cheap ones or Pololu can sell you ones with known quality, see Pololu - Step-Down Voltage Regulators

Steve