Here is the scenario: I have a project needing 3 supply powers:
- 3.3V to run the microcontroller (max 100mA)
- 5V to run a bunch of adressable LEDs (max 8A, the most current intensive)
- 12V to supply op amps (max 15mA x 6 = 90mA for all opamps supplies)
The question is: if I want to use only one power adapter brick to power this thing, is it more logic to use a 12V power supply and step down to 5V and 3.3V? Or is it better to use a 5V power supply since most of the current is used on this voltage and simply step-up to 12V for my opamp needs?
Note: All opamps are signal level, the 12V is to have maximized headroom to preprocess my analog signals.