I am currently trying to multiplex an array of four RGB matrix (8*8 LEDs each, common cathode) using an Arduino Mega. Thus, I wanted to drive all the 8 rows via NPN transistors and control each column individually (I would say via shift registers for monochromatic LEDs but I’m not quite sure about the way to drive the RGB leds, considering RGB LEDs need to be driven by PWM outputs).
What type of IC can I use if I want to drive this multiplexed array of matrix (that makes 832 LEDs, 8 rows and 84=32 columns) and update it 25 times every second (hence changing the PWM input of 8 leds 25*32=800 times every second).
I don’t have the part numbers in my head right now, but I know there are I/O expansion chips out there that have PWM capability. Do a search on them. It should not be a problem to get the expander updated 800 times per second.
Hey! Thanks for your quick reply (unlike mine. Sorry about that.)
Well, I’ve tried to drive a single 8*8 dot matrix with a TLC5940 and it kind of flickers (if the delay inside the procedure that drives the matrix LEDs + TLC is too short, LEDs that should be off are slightly apprearing turned on anyways and if this delay is too long well it flickers).
I’m not sure where the problem comes from, I could post my code but it’s a basic for loop that sends the eight PWM outputs to the TLC for every column of the matrix with a short delay (I’ve tried several, < and > 1ms but flickers anyway) and turns on and off the rows one by one.
