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I have some 50w HPLEDs I want to power. Any help on circuitry design will be wonderful!

The specs are Vf of 15-18V and 3200ma for one and 10-12Vf with 4000ma for the other.  I want to build it cheaply and maybe use the LM350 (?) and resistors (?). I'm going to use a 350W computer power supply since I got 2 of those lying around already. What resisters would I need to use and such?  Somewhere in a data sheet I found I should use a 120 Ohm for R1 but no clue how R1's rating will effect R2 in combination. I'm a novice at these things so lay it out in dumb mans terms =)

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These are BIG beasties. You'll waste an awful lot of heat drivingthem from a standard power supply and resistors - and a PC supplyhasn't really got the rails you need available with enough output. You'dactually be better buying a driver, if you haven't got the electronicsknowledge to build a switch mode constant current drive.
orbulon (author)  steveastrouk7 years ago
Couldn't I hook up +12 (red) and +5 (yellow) rails to make 17 volts? there's plenty of amps between the 2 rails to power several...
Not really safe to do that - the rails are not rated at the same current.
orbulon (author)  steveastrouk7 years ago
You mentioned a switch mode constant current drive?  Switch mode... can you elaborate on that?  Are there any instructables supplying information on how to construct one with the ratings specified?
Well, you could do worse than look at these<br /> http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5686<br />