> not very hot at all Any linear driver will have equal efficiency to any other, and PWM just changes the overall on-time, not the efficiency during that time.

> not very hot at all Any linear driver will have equal efficiency to any other, and PWM just changes the overall on-time, not the efficiency during that time. So a simple resistor, if you can live with its variability in the application, can be used just as effectively as a fancy trimmed current source. They're even relatively similar in difficulty to PWM a single output, though current sources will usually win for multiple equal outputs. > I typically run LEDs at half their rated current Half? I start at 500uA these days, or 1/10th to 1/40th of "rating", and have been known to go down as low as 50uA, with a series resistance of 100k! Modern LEDs, especially the 0402 white ones, are amazing.