johnwasser:
Since it is easy to SINK current with an NPN transistor or N-Channel MOSFET it makes sense to use Common Cathode LEDS and SOURCE drivers. Then you can SOURCE 20 mA of power from each of 300 output pins and SINK the 6A (300 anodes * 20 mA each) for each layer with a single transistor.
What would a basic setup for this be so I can learn and then possibly scale it up? Also and NPN transistor supplies current through it once I apply the voltage to the gate one it, correct? Does a MOSFET do the same?