Teardown: LED light shrinks size, cost with non-isolated driver

Margery Conner - March 6, 2013

LED bulb prices are dropping. A year ago you could expect to pay $50 for a Philips dimmable 60W-replacement LED bulb, while today you can go to Best Buy and purchase its house brand 8W, 800 lumens Insignia 60W-replacement bulb for just $17. What has changed in LED bulb design to allow this price drop? Tearing apart the bulb gives us a look into some design trends in LED lighting, such as how the LEDs are placed within the bulb and what driver architecture is used.

The Insignia bulb has a shape similar to the familiar incandescent light, with the addition of three metal heat sink fins, and a plastic bulb instead of glass (Figure 1).

Dimming is an important bulb characteristic for the US market. I used a Lutron Maestro dimming switch, with a programmable dimming control, and did a side-by-side comparison with an incandescent bulb. The Insignia dimmed consistently and smoothly, with a dimming profile similar to the incandescent bulb. You can watch a video of the dimming test here:

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Margery Conner has covered the LED industry since its beginnings. She has a BSEE from the University of California, Irvine, and produces www.designingwithLEDs.com. You can read in detail about the Insignia (Part 1, Part 2, and Part 3) and other lighting teardowns there.

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