some months ago I published this project:http://doitwireless.com/2014/09/18/wireless-led-driver-with-pca9634/
There is PCA9634, which is PWM led controller.
Now for a new project I am looking for another LED driver - for some LED current source for multiple LEDs, which works on SPI or some another similar fast bus. I need change 32 RGB LED intensity (a few steps) in less than 1ms. PWM in useless for me, because of noise, which could cause (there is hi-impedance measurement on the board).
Edit: Expected LED current about 20mA for each LED.
Have you someone any idea, which devide could I use for this project?