60 RGB-Leds - parallel?

Hi,

I need to connect 60-70 RGB-LEDs to the same three PWM-outputs. How? And im kinda new to this. I got my Arduino up and running, and its working flawless with one RGB. The LED's are rated 5v 20mA. I have got a DC 5V 2A laying arround here somewhere - can I use this? And again how?

A schematic would be much appreciated.

Regards, Michael

Ohh. They are Common-Anode's by the way...

How would the above diagram have to be altered, if I were to use a 12V powersupply instead?

How would the above diagram have to be altered, if I were to use a 12V powersupply instead?

The diagram wouldn’t change but you would waste more power - because you have common-anode RGB LED’s its not possible to chain them in series to make use of a higher voltage supply.

You need a supply capable of driving the highest voltage LED (about 4V for blue and green, so 5V is fine). It needs current handling suitable for the biggest load you are going to give it, which for 60 RGB LEDs at 20mA per colour is 3.6A or so.

You could use a 2A 5V supply if you limit to 10mA per colour per LED, or if you never switch on more than half o them.

Also I’ve just noticed you say the LEDs are rated at 5V - does this mean they have integral current-limiting? If so you won’t need the series resistors in the circuit (unless you want to limit the current even more).

The diagram wouldn't change but you would waste more power (...)

Which meens, I could use a 16V 5A instead, but I would need a bigger resistor? Or have I misunderstood?

Thanks for all your help, so far :)