djulien
03-06-2009, 03:14 AM
Has anybody used a charlie- or multi-plexed style PWM with RGB LEDs? The circuit diagrams I've seen so far all show that the R, G and B can all be on at the same time (and I presume they are, although I did not check into the firmware). This can draw 3x as much current compared to a single LED, as well as creating a larger variation in brightness.
I'm finding that sequencing through R, G and B sequentially (only one LED on at a time) will still look like white if it is faster than the eye's critical refresh rate, and I can still get blended colors okay (by altering the relative length of time each color is on). So I was wondering if anybody else had used this technique with RGB PWM control to either cut down on power consumption or I/O pin count.
thanks
don
I'm finding that sequencing through R, G and B sequentially (only one LED on at a time) will still look like white if it is faster than the eye's critical refresh rate, and I can still get blended colors okay (by altering the relative length of time each color is on). So I was wondering if anybody else had used this technique with RGB PWM control to either cut down on power consumption or I/O pin count.
thanks
don