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Turning to more familiar aspects of electronics, the two printed circuit boards residing in the base are dedicated to power conversion and LED mounting respectively. The power conversion here is a (120-V) AC-to-DC conversion for the most part. The 12 WLEDS arrayed on the second board are arranged as two series strings of six WLEDs each. A specialty IC may be the controller for the switching power supply but an additional feature of the LR6 may also hinge on the LEA001 "mystery part."

In the photo (previous page), where the lamps have been turned on you see red LEDs between the arrayed WLEDS. These red lamps have been added to "warm up" the effective color temperature of the output to mimic incandescents, and their brightness is set by the light incident on the photodiode in the lower left corner of the LED board (the photodiode is on the green patch). The system uses the diode to calibrate the red content by responding to generated WLED output, which itself can vary due to manufacturing variations.

Not all's well in LumenLand

The drive for widespread adoption of more-efficient lights may not be a slam-dunk however, at least in my book. CFLs have a limited lifetime of their own and LEDs at present are far too costly to move mainstream. Perhaps more significant, achieving the broad-spectrum color-temperature aesthetics of incandescents with either CFLs or LEDs remains an elusive goal. Lumens/watt for both alternatives are clearly superior to conventional light but the "peaky" aspects of CFL and LED output still leaves me a little cold. A green form of white (light) may be getting closer but when I'm reading or working a crossword tonight, I'll still be turning on a tungsten-filament bulb.

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David Carey is president of Portelligent, a TechInsights company that produces teardown reports and related industry research on wireless, mobile and personal electronics.