Hi all,
Just got myself my first Arduino 
love this thing!
I have been playing around with some of the basic tutorials and have just setup the one using a 10k pot to send a PWM signal to dim a standard LED.
I would like to be able to use the PWM signal to switch a TO220 mosfet (IRF540A) to power a 3W 700mA 3.8v Power LED from a 3-9W 700mA constant current power supply.
http://www.maplin.co.uk/3w-high-power-led-with-pcb-511371
http://www.maplin.co.uk/constant-current-led-power-supply-511375
I think the power supply is probably a switch mode one that doesn't support dimming on the unit, is it ok to use this type of driver?
Eventually I would like to be able to control a pair of power LED's a white and a blue with two pot's to dim them both independently.
I have seen a few simple constant current drive circuits using a voltage regulator, do you think I would be better off using one of these?
Any help regarding circuit layout would be greatly appreciated.
I'm worried about getting it wrong and damaging my laptop.