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Regulated Power Supply for LED Spot Light

bheemarao

Hi

 

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

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  • 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.

  • in reply to WarrenW

    Thanks Warren,

     

    I will try changing C3 to 1000uf.

     

     

    Best Rdgs

    Bheema

  • 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