LED dimmer for high current applications
Pulse width modulation (PWM) is the most efficient way to do this. The basic principle is that you cycle the LEDs on and off at a speed fast enough that the eye can't detect a flicker - say 50 times a second. By varying the % on-time from 0 to 100% the LEDs can go from 0 to 100% brightness. The  advantages are:


The power circuit is very simple.
No power is used while their off.


We need to know what is going to control the dimmer if we are to provide further information.