I am using 1 Amp constant current regulators, composed of 3 AMC7135 current regulators in parallel (http://www.micro-bridge.com/data/ADD/AMC7135.pdf), to drive Luxeon K2 LEDs (I know, lower than their maximum current but the difference in brightness is negligible). I wanted to ask whether I should PWM the inputs or the outputs of the boards using MOSFETs to change the brightness of the LEDs. Any recommendations?
You could do if efficiency is an issue, or you could try a variable current source (would still require a MOSFET) (this one can do up to 440mA), or perhaps even just a chunky resistor in series with the LEDs.
Efficiency isn't an issue (I'm not running these from batteries), but I just want to make sure the switching doesn't damage the boards. These are the bad boys I've got: http://www.dealextreme.com/details.dx/sku.1885
