RGB LED driver, Any comments?

[KD6OJI]

Try using a 1K pull down from the gate to ground on your MOSFET's. I have found that sometimes they get a little flaky with PWM and the 1K seems to make a huge difference.

[ERIK]

Ya did put some 1K's on and found the same thing, that it all worked perfectly. I should've come back to this post with that. Strange that I haven't seen any mention of doing that anywhere else.

[paxmowa]

I don't know for sure,

since i changed my computer I should digg out the old schematics somewhere. But I'm pretty sure that there where pulldown resistors in my design. It's never a good thing to leave the pics pin floating in mid air, which will always cause weird results.

This being said, does anyone think it's feasable to design a RGB christmas light with 50 channels from one PIC controller, prefferably 16C class? I don't think it can be done. Last year with the 8 channel set-up, it was already clear that the switching between the colours was getting a bit iffy to say the least, colours bleeded a bit from one transistion to another when working with 2 or more colours at the same time. I would use decimal counters to go down the row of leds, but I don't think it could be switched fast enough to at least have a flicker-free view.

It was programmed like this:

set pwm for red - green - blue
turn on all used channels
wait a few msec
turn off all channels
set pwm for red - green - blue
turn on all used channels
wait a few msec
turn off all channels
etc...

When I wanted one out of two leds to be red and the other ones blue, I ended up with a light shade of blue and a shade of pink, which made me think the PWM channels didn't ramp down fast enough or something.

Steve