yes thank-you, but what about when the layer of matrix is bigger, that will increase the number of max led's that need brightening when all on, but then what if only one is on, it may get too much current(?),
or is it best to stick to 12 leds per ULN2003,?
maybe there is like a digital controlled current reg?
Or maybe I could take out 74LS registers on ULN and use adjustable pulse width to control the current on matrix(?)
I really like that max ic but it just dont beat price margins.