Multiple Suplies

Design Concepts
1

Hello Guys!

My project has a lot of LEDs and current is a bit high. Something around 500mA only for the leds.

I made 2 supplies:

1 (7805) for the CORE. I’m reading 5,04 V.

2 (7805) for the Leds and buttons. I’m reading 5,02 V (oscilates a bit) with 500mA. BUT Its very, very, VERY HOT, whit a heatsink. I haven’t tested for more than 3 minutes

The main supply has something around 15V.

In my last attempt i use a 5V switched supply (cellphone charger) that says 5V 750mA.

So i tried to put her for leds only, and Im reading 4,93 V/500mA. (Its working about one hour and supply is just a little warm)

Finaly the question:

I can have some problems with the small diference of voltage between the core and leds supply?

My idea is use two switched suplies, one of 750mA for core and other stuff.

And another for high current.

Anther question:

whats the diference between the 74hc595 pin 16 and pin 10? (5v supplies)

Thanks

2

Hi!

Regarding the voltage regulators - i ´d suggest only using one high-power voltage regulator, e.g. a 78S05 (2 Amps max) with a large heatsink, and a big load resistor ahead of it to burn off excess volts, so that the vreg gets fed optimum input voltage (it has to burn off excess voltage, so if you feed it 15V, it has to burn off the difference to the target voltage, which generates a lot of heat).

If you are developing a non-audio MIDIbox (e.g. a MBSEQ), you could employ a switching 5V power supply with 3 Amps, these are really cheap and power efficient.

Greets,

Peter