Archive for February 19th, 2010
Flexible drivers enable dynamic color-changing lighting projects
Color-changing lighting using LEDs has been around now for over 10 years, and is now, probably, the dominant lighting technology in architectural and entertainment dynamic lighting applications. LED technology has continued to evolve, often with the addition of a 4th control channel—white or amber—to expand the color gamut. Moreover, multi-chip LEDs have improved the color-mixing cabilities of lighting fixtures.
Over the same period, the range of options to drive the LEDs has also expanded dramatically. However, many of these sophisticated solutions are chip-based and require extensive electronics expertise and investment to arrive at a final drive solution. This may be fine for entertainment companies with in-house electronics capabilities, but, in the architectural and general lighting segments, dynamic color-change projects are often project-specific and have to be supplied on short delivery times.
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This article was published in the Jan/Feb 2010 issue of LEDs Magazine. To read the full version of this article, please visit our magazine page, where you can download FREE electronic PDF versions of all issues of LEDs Magazine. You can also request a print copy of LEDs Magazine (available by paid subscription) and sign up for our free weekly email newsletter.
About the Author
GORDON ROUTLEDGE is in charge of UK Business Development for eldoLED (www.eldoled.com), a privately-owned company with headquarters in Eindhoven, The Netherlands.
Coordinated schemes provide circuit protection for LED lighting
Posted by LED Larry in New LED Technology on February 19th, 2010
Utilizing a coordinated circuit protection scheme based on several device types can help designers reduce component count, provide a safe and reliable product, comply with regulatory agency requirements, and reduce warranty and repair costs, writes FARAZ HASAN.
LED technology has advanced rapidly, with improved chip designs and materials facilitating the development of brighter, more energy efficient, and longer-lasting light sources that can be used in a wide spectrum of applications. In spite of the technology’s growing popularity, LED light manufacturers continue to wrestle with the fact that LED luminaires are extremely heat-sensitive. Without adequate thermal management, heat can degrade the LED’s lifespan and affect color output. Also, because LED drivers are silicon devices, they can fail short. This means fail-safe back-up overcurrent protection may be required.
Resettable polymeric positive temperature coefficient (PPTC) devices have demonstrated their effectiveness in a variety of LED lighting applications. Like traditional fuses, they limit current after specified limits are exceeded. However, unlike fuses, PPTC devices have the ability to reset after the fault is cleared and the power is cycled. A variety of overvoltage protection devices—including metal oxide varistors (MOVs), electrostatic-discharge (ESD) surge protection devices, and polymer-enhanced Zener diodes—can be used in a coordinated scheme with PPTC devices to help improve LED performance and reliability.
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This article was published in the Jan/Feb 2010 issue of LEDs Magazine. To read the full version of this article, please visit our magazine page, where you can download FREE electronic PDF versions of all issues of LEDs Magazine. You can also request a print copy of LEDs Magazine (available by paid subscription) and sign up for our free weekly email newsletter.
About the Author
FARAZ HASAN is Global Marketing & Business Development Manager–Appliance/Industrial/Lighting for Tyco Electronics Circuit Protection Products.
Cities are transforming the outdoor lighting market, but barriers remain
| A global trial is strengthening the case for LED acceptance by municipal lighting asset managers, says PHILIP JESSUP of THE CLIMATE GROUP. | |
| In 1893, visitors to Chicago’s Columbian Exposition were awestruck by the blaze of artificial light that bathed the fairground’s neo-Renaissance streets and plazas. Aglow at night with 93,000 electric lamps, the fairgrounds were dubbed the White City. Searchlights alone consumed more electricity than the entire city of Chicago, reports John Jakle in his definitive City Lights. The Exposition’s 16 million dazzled visitors spread the word. To emulate the White City, municipal governments began converting their archaic oil and gas street lamps to electric lights. Cities would never be the same.
Thus, municipal governments historically became important players in the transformation of lighting markets. During the late 1800s, they set up their own companies to raise capital to install gas street lighting on commercial streets. When electricity brought brighter light, they made large financial contracts with fledgling private utilities to convert the old to the new. ++++++ This article was published in the Jan/Feb 2010 issue of LEDs Magazine. To read the full version of this article, please visit our magazine page, where you can download FREE electronic PDF versions of all issues of LEDs Magazine. You can also request a print copy of LEDs Magazine (available by paid subscription) and sign up for our free weekly email newsletter. |
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| About the Author | |
| Philip Jessup is Cities and Technology Director at The Climate Group |
LED modules for accent lighting surpass the performance of halogen lamps
| Modules built using separated phosphor technology demonstrate that the benefits of LEDs can be harnessed in the realm of accent lighting with no compromises in light quality, even taking halogen as a benchmark, as ROGER SEXTON describes. | |
| In the 1970s, the advent of dichroic halogen lamps allowed high-quality accent lighting in retail, hospitality, museums and other applications. From the 1990s until now, compact metal halide lamps have also been used in these applications offering more “punch” (for example, highlighting of merchandise even against the higher background illumination levels of department stores) alongside improvements in longevity and energy consumption.
At the beginning of this decade, highbrightness LEDs showed the promise that more improvements still could be made in terms of longevity. However, until now, light output and efficacy, luminaire size and light quality compromises have been barriers to adoption. ++++++ This article was published in the Jan/Feb 2010 issue of LEDs Magazine. To read the full version of this article, please visit our magazine page, where you can download FREE electronic PDF versions of all issues of LEDs Magazine. You can also request a print copy of LEDs Magazine (available by paid subscription) and sign up for our free weekly email newsletter. |
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| About the Author | |
| ROGER SEXTON is VP of Marketing and R&D at Xicato (www.xicato.com). |
LED TV backlights to drive escalation in LED production (MAGAZINE)
| Analysts forecast a ramp in LED-backlit LCD TV sales, but will LED makers be able to deliver the required capacity? MAURY WRIGHT reports. | |
| There’s a very good chance that LED-backlit LCD TVs in all sizes will significantly boost LED production requirements immediately and over the next few years. Most indications—including analyst projections and product introductions at the recent Consumer Electronics Show— point to a faster uptake of LED backlighting than previously predicted. But can the LED suppliers handle the increased demand, and will consumers actually pay the premium for LED-backlit TVs? We can’t definitively answer these questions, but we can see an unmistakable trend toward LED backlighting.
Bruce Berkoff, chairman of the LCD TV Association, states “LED-backlit TVs are going to take over the industry.” Berkoff won’t predict when LED-backlit sets will take a predominant share of market, but he can tell you why. According to Berkoff, consumers care about three things in buying large-screen TVs—“image quality, WAF (wife acceptance factor), and green.” Berkoff states, “LED-backlit sets win in all three areas.” ++++++ This article was published in the Jan/Feb 2010 issue of LEDs Magazine. To read the full version of this article, please visit our magazine page, where you can download FREE electronic PDF versions of all issues of LEDs Magazine. You can also request a print copy of LEDs Magazine (available by paid subscription) and sign up for our free weekly email newsletter. |
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| About the Author | |
| Maury Wright is the Senior Technical Editor of LEDs Magazine |