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Current/voltage regulator

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Lynx46

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Hellow there... I'm new and my english is not so good so appologies at the beginning...

To the point... I have a PowerLED 5W that needs 6.2V and 750mA and I need some kind of regulator but not on the LM317 because it is not stable enough... My input voltage will be 12V or in my case car battery supply cause they will go inside my headlamps for daylights that my xenon lamps would not work during the day...

So some kind of regulator stable aneough will do it but I can't find any that would do it... I alread burnt one LED on LM317 built circuit... So if you guys have any idea or any kind of circuit diagram or if anybody will be willing to make one sketch for me will be more than welcome!

Thanks in advance!

Regards from Slovenia


Mihael
 

There should not be any issue with a current source configuration on an LM317, however you are going to have significant heat to dissipate with 6 volts of drop from 12v with 750 mA. With greater then 4.5 watts of heat to dissipate it will require a reasonable sized heat sink for any linear current source regulator. With an auto running between 12v and 14.5v just a 9.4 ohm dropping power resistor will only have a +/- 9.4% current variation on the 750 mA nominal.

More complicated but have you considered an LED current sourcing switching regulator?
 
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    Lynx46

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Thanks man! Because this goes boyond my knowledge and stage of study of electronics where I am now... So if anyone will be willing to make a simple sketch in Paint of circuit that outputs 6.2V and 750mA for 5W LED and runs on 12-14.5V of input power... Heatsink is not a problem cause there is plenty of room to spare in each headlamp for circuit... I will also have to have a big heatsink for LED because this little babys put quite a lot of heat out when running on full power...
 

Problem solved... I won't buy it but build it myself to practice a little bit... Thanks all!
 

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