How to Design High Power LEDs

It's well-established that light-emitting diodes are efficient. Efficacy --- the way the lighting industry categorizes efficiency --- can be better than 100 lumens per watt, 10 times higher than incandescent bulbs. But just because they're efficient, doesn't mean they're bright. Standard LEDs put out a lot of light relative to the tiny amount of electricity they use, but it's a little harder to put out a lot of light relative to a higher amount of electrical power. High-power LEDs are different. A single high-power LED can provide more than 1,000 lumens, more than a 60-watt bulb. To make a fixture with these high-power diodes, industry goes through some detailed calculations and design. It's difficult to duplicate that at home, but attention to the same details will help.

Things You'll Need

• LED
• Heatsink
• Drive electronics
• Optics

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Instructions

1. • 1

     Select an LED or LEDs based upon the light output and light distribution needed for the application. The LED specifications will outline the light output, electrical requirements and thermal and mechanical interface for the LED. Some applications requiring high levels of illumination may need more than one LED.

   • 2

     Select or design drive electronics that will convert the AC line power to the current-controlled DC power needed for the LED. Most electronic drivers will not be compatible with conventional dimmers, so take care to investigate dimming schemes if that's desired.

   • 3

     Attach the LED package to a heatsink. Good thermal contact is important. If the temperature gets too high, all bets are off --- light output will decrease and lifetime will be short.

   • 4

     Integrate the package into secondary optics --- whatever reflectors, lenses, or diffusers are needed to shape the light to meet the need. This can be a complex process. LED fixture manufacturers use nonlinear raytrace programs to maximize efficiency and be certain they don't throw away too much light.

   • 5

     Put the whole package in a mechanical assembly that is attractive and functional. Industry players put a lot of effort into this step and it will be difficult to duplicate their process at home, but home-made designs can have their own charm.