Brenn Posted August 8, 2004 Report Share Posted August 8, 2004 Hi im just trying to get a rough idea of what type of supply i would need to run about 4 or 5, 1w luxeon leds from a 12-13v car battery source, the 2 links below are nearly exactly wat im looking for, after i get this to work i might build up a sound sensitive cct to use with it aswell any suggestions or cct diagrams hehehe? im thinking a switch mode power supply but im not sure what these 2 modelec ccts are some kinda pulse driver? it say u dont see the pulses, sooo hmmm? oh yeh www.lumileds.com for more info on these 1w leds. thankshttp://www.reprise.com/modelec/pd-1.pdfhttp://www.reprise.com/modelec/md-41v.pdfhttp://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3240&item=5912592834&rd=1http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3240&item=5913088345&rd=1http://www1.jaycar.com.au/productView.asp?ID=KC5389&CATID=&keywords=luxeon&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATIDCheersBrenn Quote Link to comment Share on other sites More sharing options...
vainajala Posted August 9, 2004 Report Share Posted August 9, 2004 Hello BrennWhich color Luxeon's are you going to use? Red Luxeon has forward voltage of 2,85V and blue has 3,42V. Four red Luxeons connected in series would have forward voltage of 11,4V.Simplest method for dropping voltage would be a series resistor.(13V-11,4V)/0,35A = 4,6 ohm => 5,6 ohm 2 watt resistor in series with the LED chain.For blue Luxeons, you could connect them series/parallel. For example, two chains of two series-connected LEDs, with each chain has its own series resistor. In this case,(13V-6,84V)/0,35A = 17,6 ohm => 18 ohm 5 watt series resistor for each chain.If you're interested about switch-mode's higer effiency, have a look at switch-mode regulator ICs from National and Maxim.LM2595T-ADJ:http://www.national.com/pf/LM/LM2595.html Quote Link to comment Share on other sites More sharing options...
Ldanielrosa Posted August 10, 2004 Report Share Posted August 10, 2004 There are a few variants of a switchmode regulator at http://www.romanblack.com Quote Link to comment Share on other sites More sharing options...
AJB2K3 Posted August 10, 2004 Report Share Posted August 10, 2004 You do know that kinda circuit is illegal in the uk unless used of road or at shows?Halfords sell 4 X 5mm blue prewired for 12 volts that are bright, i had to adjust mine after a dash mount led lit up my windscreen. Quote Link to comment Share on other sites More sharing options...
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