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I'm thinking of using few of the CREE LEDs but wondering what all would i need to build a bulb from scratch.

Here's what I've got:

  • LEDs (of course)
  • LED high current drivers
  • some sort of rectifier circuit for AC to DC
  • heatsink

Any other details or resource you guys can point me to? I'll make my designs, schematic, PCB and BOM open source.

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  • \$\begingroup\$ You've pretty much got it - if you choose a driver IC, it will probaby come with a reference design. Take care on the AC side; keep it well away from everything else and suitably insulated. \$\endgroup\$
    – pjc50
    Feb 17, 2013 at 13:08
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    \$\begingroup\$ Also see this new product launch by Atmel ... They may be offering samples and reference designs. \$\endgroup\$ Feb 17, 2013 at 18:42
  • \$\begingroup\$ ... EMI filter, connector(s) corresponding to the light bulb socket(s). \$\endgroup\$ Feb 17, 2013 at 20:16
  • \$\begingroup\$ ... offline converter (very few LED drivers work straight off rectified line voltages) \$\endgroup\$
    – user16324
    Feb 17, 2013 at 20:34
  • \$\begingroup\$ hmm can you suggest a existing circuit design I can launch off from ? \$\endgroup\$ Feb 17, 2013 at 21:02

2 Answers 2

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This can be such a general question that it really depends on what problem/challenge you are trying to solve. How much light do you need and how wide of an angle of distribution do you need? I purchased many thousands of OSRAM TopLED plus (warm white) SMD LEDs for little over 4 cents each. In an array you can generate a reasonable amount of light with only the PC board dissipating heat. If you want higher levels of light you typically need a heat sink and a way to manage the current draw from the LEDs. Now that I can buy a 75 watt equivalent flood lamp bulb from Feit Electric for ~$20, I do not try to build large LED bulbs since it would cost me as much or more to produce them.

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As you have listed, that is essentially all you need, except for the bulb connector and maybe a lens. An LED bulb is simply a mains voltage compatible LED driving circuit, which fits into a specific form factor. It is shaped and connects to the same type of bulb socket as an incandescent bulb does. Only thing you need to ensure is that the power draw is less than the bulb socket and lamp housing's maximum rating (45W to 75W depending on the lamp). You just need to ensure your design fits in that spacing.

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