White Paper | Technology | Mar 06, 2012

At High Environmental Temperatures and at Very Low Power LED's Wall Plug Efficiency Exceeds 100%

For the first time, researchers have demonstrated that an LED can emit more optical power than the electrical power it consumes. Although scientifically intriguing, the results won’t immediately result in ultra-efficient commercial LEDs since the demonstration works only for LEDs with very low input power that produce very small amounts of light and emits primarily in the invisible IR range of 2.4 µm. Read more »

White Paper | Technology | Feb 07, 2012

Power Integrations - 15.3 W Dimmable LED Driver Design for PAR30/PAR38 Applications

The engineering team at PI just released an isolated, high power factor, TRIAC dimmable, LED driver design for PAR30/PAR38 applications. Design Example Report 314 (DER-314) is designed to drive a nominal LED string voltage of 36 V at 425 mA from an input voltage range of 185 VAC to 265 VAC. Read more »

White Paper | Technology | Jan 13, 2012

Success in Research: First Gallium-Nitride LED Chips on Silicon in Pilot Stage

Researchers at Osram Opto Semiconductors have succeeded in manufacturing highperformance prototypes of blue and white LEDs, in which the light-emitting gallium-nitride layers are grown on silicon wafers with a diameter of 150 millimeters. The silicon replaces the sapphire commonly used until now without a loss in quality. Already in the pilot stage, the new LED chips are to be tested under practical conditions, meaning that the first LEDs on silicon from Osram Opto Semiconductors could hit the market in just two years. Read more »

White Paper | IP, Reports & Roadmaps | Jan 11, 2012

DOE Releases Consortium Report on LED Street Lights

The U.S. Department of Energy (DOE) has published the final report from a demonstration of LED technology in ornamental post-top street lights, conducted in Sacramento, CA. This report provides an overview of the evaluation of four different LED replacement products using computer simulations, field measurements, and laboratory testing. The evaluation was conducted by DOE’s Municipal Solid-State Street Lighting Consortium in collaboration with the Sacramento Municipal Utility District and the City of Sacramento, with additional support from City consultant Mary Matteson Bryan. Read more »

White Paper | Technology | Dec 15, 2011

Independent Study Demonstrating that Pink Sapphire Produces Highest Transmission Colorless Epi-Wafers

GT Advanced Technologies Inc. announced the release of a case study that details the findings of a series of blind material studies conducted to evaluate the impact of sapphire color on the LED manufacturing process. The studies demonstrated that all sapphire, regardless of source, exhibits color at the core level, that the pink hue of GT Advanced Sapphire Furnace (ASF™) material is not indicative of impurities, and that pink ASF sapphire does not have an adverse affect on the LED manufacturing process nor does it require extra steps or incremental costs to remove the pink hue. In addition, it was demonstrated that GT ASF pink sapphire material makes the lowest absorption, highest transmission epi-wafers of the samples examined. Read more »

White Paper | Technology | Dec 01, 2011

New LED Driver Design from Power Integrations Maximizes Efficiency of Compact B10, GU10, E17 and A19 Bulbs

Power Integrations, maker of the world's most efficient, longest-lasting off-line LED driver ICs, today published a reference design (DER-297) describing a high-efficiency, ultra-compact driver for a B10-style LED light bulb. Based on Power Integrations' LinkSwitch-PL non-isolated, single-stage LED driver IC, the power supply is specifically tailored for use with high-voltage LEDs such as the recently announced XLamp XM-L and XLamp XT-E ranges from Cree. DER-297 provides the high-voltage output required by the LEDs, optimizing overall system efficiency by reducing power lost due to current flow in the driver inductor and output diode. Read more »

White Paper | Technology | Jul 28, 2010

Cree Study Shows LED Lighting is Best Bet for Energy Efficiency

A new report on the life-cycle energy usage of energy-efficient lighting by Cree, Inc. shows that LED lighting products are now more efficient than traditional lighting products when compared across the high-volume applications of recessed downlighting and display spotlighting. Evaluating light fixtures and applications, the white paper’s energy comparisons demonstrate that LEDs offer clear advantages in terms of energy costs and environmental impact over traditional lighting such as incandescent, halogen and compact fluorescent bulbs. Read more »

White Paper | Standardization + Regulation | Dec 31, 1969

Solid State Lighting for Incandescent Replacement—Best Practices for Dimming

This paper focuses on integrated LED lamps intended for replacement of general service incandescent lamps. Future white papers are planned to address other LED dimming topics, such as: color change; light output and efficiency (dimming curve); dimming protocols (Internet protocols, 0-10); LED modules with auxiliary drivers; and control architectures that dim without modulated power. Read more »