I'm designing a circuit that will have:
- ATmega328 running at 3.3V
- 2x 74C923
- 2x PCF8574
- 30x MX Cherry switches, each with a currant rating of 10mA
This PCB will then connect via a ribbon cable to a couple of PCBs each holding 6x MAX7219, with 7-segment LEDs, 1x 2-digit, 1x 4-digit, and 10x 3-digit.
My question is can someone advise on the power requirements for this circuit and hopefully give me a link to a web page that shows me how I would design the power into the circuit. My initial plan was a DC power jack connected to a 7805 regulator with a capacitor on both the input side and the output side. But, as this would supply 1 AMP I doubt that will be sufficient. I'm hoping someone can advise please.