Regulated Power Supply for LED Spot Light

My requirement is Power supply for LED Spot light.

i want to drive 5 High power LED 18V @ 700mA so i am into design of power supply and the component should be easily available.

can any one suggest me the solution

Best Rgds

Bheema

ksmith over 15 years ago in reply to bheemarao

Thanks Bheema.

If you are interested in comparing the cost / performance of a standard commercial ac/dc supply (or dc/dc) to power the LED driver please let me know. It may be worth a quick comparison for you.

Kent Smith
Applications Engineer
ksmith@xppower.com
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bheemarao over 15 years ago in reply to ksmith

Hi Kent,

Yes i would be interested in comparision on different standard commercial ac/dc supply (or dc/dc) to power the LED driver.

and also as a simple regulated power supply i have selected LM350 which is an variable output one.

Best Rdgs
Bheema
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ksmith over 15 years ago in reply to bheemarao

Bheema,

Please send me an email to ksmith@xppower.com and I can get your contact information to the correct people to work with you in selecting the best products to show you for your comparison purposes.

Thanks,

-Kent Smith
XP Power
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bheemarao over 15 years ago

Hi,

i had done the below circuit and tested, it is working fine but the maximum current deliver in only 200mA max, can any one suggest me the solution for driving 1A.

Best Rgds
Bheema
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WarrenW over 15 years ago in reply to bheemarao

Looking at the design, it seems this is most likely drive from main voltages and therefore quite likely to be a 50 or 60 Hz supply. In this case the capacitor you have choosen as you filter (1uF C3) is way too small. Try increasing it to 1000uF. As a general rule of thumb I use 1000uF per Amper per volt drop as a guidline. e.g 1000uF filter @ 1 A load should equate to approx 1 volts drop in the supply volts to the regulator. You have shown a 1uF filter capacitor (C3) so virtually no regulation exists before the LM350 and I would expect in those circumstances to see quite an AC component on your 'regulated' DC output.

Cheers

Warren.
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bheemarao over 15 years ago in reply to WarrenW

Thanks Warren,

I will try changing C3 to 1000uf.

Best Rdgs
Bheema
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enrico.migchels over 15 years ago in reply to bheemarao

Hi Bheema,

Surprising to see that your power supply design is a linear device; transformer and linear regulator. This is really old techology and will make your system perform poor. There is only benefit with your design. It is simple to design, but that should be no argument anymore these days. There are plenty off the shelve products and designs efficient switching power supplies.

Best regards, Enrico Migchels
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