I am trying to figure out some electrical values for a circuit I am designing. I am wiring 66 RGB CA LEDs in parallel. Each color channel takes 20mA (2.2v for Red and 3.2v for Green and Blue). How do I figure out the total ammout of current I'll need to drive each channel?
If you run all colours at the maximum rated current of 20 mA, that will be 60 mA per RGB LED. for 66 RGB LEDs, you will need 3.96 amp.
If you run at a lower current, for less brightness, or know that all three colours won't be on at the same time, you will require less current.
Nch FET will drive 66*20mA =1.32A per colour, so for 100mV drop or less RdsOn=<0.1/1.32 Ohms and Vgs(th)<=1/3 Gate voltage with each LED having a current limiting R.
Red =(5-2.0-0.1)/20mA=145 Ohms per Red and BG R’s = (5-3.1-0.1)/20mA= 90 Ohms
PSU needs to be 5V 5A 2% or better.