> I'm wondering if it is possible to adapt one of the "Roman 
> Black" SMPS voltage regulators to drive a 1Watt Luxeon 
> LED.
> The supply voltage is a 6V-4Ah lead acid battery and I 
> need  to drive ONE single LED at 250-300ma (75-80% 
> efficency may be enough).
> This is the link of the Roman Black "current-limited" 
> version:
>
> http://www.romanblack.com/smps/a04.htm

Roman's circuit is excellent as a minimum parts count 
regulator, but the "GSR" circuit will do what you want and 
have better regulation than Roman's circuit.

for a version of this that does exactly what you want see

        http://www.piclist.com/techref/postbot.asp?by=time&id=piclist\2006\11\07\140224a.txt


Some background

        http://www.piclist.com/techref/postbot.asp?by=time&id=piclist\2006\11\07\140224a.txt

and a voltage regulating version

        http://sound.westhost.com//appnotes/an006.htm



            Russell McMahon


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