Electronic – Question on RGB LED Array

driverledpicpwm

I have been looking around at 4x4x4 and 8x8x8 LED Cubes and I had a couple of question about them. A few I have seen have a full range of colors from the LEDs which I am assuming means they are using some kind of LED driver with PWM to control them. Looking around though I wasn't able to find many chips that support more than around 8 RGB LEDs and for 8x8x8 cube that would mean 64 chips which would get pricey fast.

So if I were to try to create one of these cubes and control it from my PIC, what would be the best and/or most cost effective way of controlling this many RGB LEDs?

EDIT: Currently looking at the TLC5940.

Best Answer

You can multiplex it to save drivers, up to about 8:1, but need a fair amount of speed to update sufficiently fast as you need to reload the drivers for each row, and row update needs to be fast enough to avoid flicker - something like 4ms for 12 bit PWM at 8:1 wih 1MHz PWM clock - you're probably going to need something with more grunt than an 8 bit MCU.