The Texas Instruments TLC5940 chip will do 12-bit PWM on 16 current-controlled outputs:
It can sink up to 17V (0-120 mA) so you can put a bunch of LEDs in series. Four of them will give you 64 channels.
The Texas Instruments TLC5940 chip will do 12-bit PWM on 16 current-controlled outputs:
It can sink up to 17V (0-120 mA) so you can put a bunch of LEDs in series. Four of them will give you 64 channels.