I have several LED strings that I need to be drive from a car battery with as few components as possible, while dimming them all together. I'm using these CREE SMD LEDs, which are rated at 50mA with a Vf of 3.8v, and am, at the moment, hooking them up in strings of two. I have found a bunch of schematics and techniques for driving one string of LEDs with dimming capabilities, but I can't seem to find any that address multiple strings. I was originally pursuing PWM dimming, but this requires the LED strings to be driven to 50 mA at all times, which itself requires an IC and a lot of external components per string. This is a problem because I am limited on available board space, and have a crowded space with the LEDs already (I'd like to use a total of 800 mA for this project).
Can anyone recommend a good, simple method of regulating multiple LED strings' power while also allowing dimming capabilities for the entire board?
Can anyone recommend a good, simple method of regulating multiple LED strings' power while also allowing dimming capabilities for the entire board?