White Paper | Technology | Oct 08, 2013

Two-Switch Flyback Solution for LED Street Lighting

Won-Seok Kang has worked for Fairchild Semiconductor since 2006 and is currently an Industrial Senior Application Engineer for Fairchild’s Switch Mode Power Supply in the Power Conversion Division located in Korea. His research interests are in functional power module, LED drivers, resonant and soft switching dc/dc converters, and electronic ballast. He has a B.S. and M.S. degree in electronics engineering LEDs provide high efficiency and long life compared to conventional lighting sources. Therefore, they are becoming first priority of lamp types to reduce energy consumption for internal or external lighting. This is also the case in street lightings where better efficiency and longer life are essential for less cost. A switching power supply designed to power up LED lamp should also have high efficiency and robustness to assure maintenance free lifetime as long as LED lamp. Resonant converters are one of the most popular power supply topologies here since their performance delivers increased power efficiency. LLC resonant converter has drawn attention thanks to its features such as high power conversion efficiency and low voltage stress on secondary rectifier. However, complicated design and high manufacturing cost of LLC resonant converters have been obstacles to fast time-to-market and cost reduction. Another problem of LLC resonant converter is large circulating current that is required to maintain zero voltage switching (ZVS). It causes relatively high power consumption at light load. LLC resonant converter also has potential failure issue when MOSFET with poor body diode performance is used. Two-switch flyback converter is proposed as an alternative solution to overcome the limitations of the LLC resonant converter. With additional switch on the high side, leakage inductance energy is clamped and recycled back to input to improve efficiency. The dissipative snubber circuit is no longer needed. A 120W rated switching power supply is designed utilizing two-switch flyback topology. The details of design specification and test results are presented. Read more »

White Paper | Technology | Oct 08, 2013

Why Pin Fin LED Coolers Perform Better Under Tilted Position?

For passive cooling, both, simulation and measurement results demonstrate the advanages of a pin fin design over conventional fins when tilted more than 50° For the experiment we compare the ModuLED 9980 with the LPF11180-ZHE. The ModuLED 9980 is a passive LED cooler from extruded aluminium with a diameter. of 99mm and a height of 80 millimeter, thermal resistance under vertical position 1.02°C/W. The LPF11180-ZHE is a passive LED cooler with pin fin structure with a diameter of 111mm and a height of 80mm, thermal resistance under vertical position 1.07°C/W. Read more »

White Paper | IP, Reports & Roadmaps | Sep 12, 2013

New Comprehensive Investigation on LED Phosphors and Down-Converters Patents

Basic phosphor respectively light conversion IP licensing structure Yole Développement announces its new market & technology patent investigation, LED Phosphors and Down-Converters. Hundreds of companies are involved in LED phosphor IP. Most of the major LED players are present in the list of the top patent assignees. But independent phosphor manufacturers are also emerging as major forces in the IP landscape. Read more »

White Paper | IP, Reports & Roadmaps | Jul 30, 2013

DoE Publishes CALiPER Snapshot Report on Outdoor Area Lighting

While most products perform well above the DLC QPL efficacy and output criteria, in the roadway category, where the incumbent technology is predominantly HPS, few LED products listed by LED Lighting Facts appear to be suitable alternatives to nominally 400 W luminaires The U.S. Department of Energy's CALiPER program has released a Snapshot Report on outdoor area lighting, which utilizes the LED Lighting Facts® program's extensive product database to help industry stakeholders understand the current state and trajectory of the market for LED outdoor area and roadway, parking garage, and canopy luminaires. Read more »

White Paper | Jul 02, 2013

Alternative Calculation Method Will Improve Thermal Analysis of LEDs - by Michiel Krüger, Ph.D. - Philips Lumileds

Figure 1: LED Definition An alternative method to estimate the amount of heat generated by LEDs will help increase the accuracy and streamline the thermal analysis of white LEDs. Up until now, thermal analysis of white LEDs has been an imperfect science. Too often LED lamp and luminaire manufacturers rely on insufficient, inaccurate or intangible data to determine the thermal performance of the LEDs in their applications, and, as a result, may over-engineer their heat sink design. Read more »

White Paper | Standardization + Regulation | Jun 26, 2013

Zhaga Announces Several Updates and Reports About Activities in their Latest June Newsletter

June has been a very busy month for Zhaga, with the consortium’s first meeting in China combined with an open session for government officials and representatives from China’s lighting industry. Meanwhile, the first products have now been certified for Zhaga interface specification Books 4, 7 and 8, while Zhaga has signed a liaison with the Global Lighting Association. Read more »

White Paper | Standardization + Regulation | Apr 22, 2013

Model Specification for Adaptive Control and Remote Monitoring of LED Roadway Luminaires, V1.0

The DOE Municipal Solid-State Street Lighting Consortium's Model Specification for Adaptive Control and Remote Monitoring of LED Roadway Luminaires is a tool designed to help cities, utilities, and other local agencies accelerate their adoption of systems that can further reduce the energy and maintenance costs of operating their streetlights. Read more »

Fundings + Projects | White Paper | Feb 27, 2013

NEWLED Research Project Led by the University of Dundee Aims to Revolutionize the Way the World Is Lit

"Bulb is over" was a provoking statement on LpS 2013 - NEWLED could make that reality The way the world is lit up could be revolutionised by a new European-wide research project being lead by the University of Dundee. The 11.8million Euros NEWLED project aims to develop a new generation of white light-emitting LED lights, which would be much more efficient than existing light bulbs. Read more »

White Paper | Standardization + Regulation | Feb 26, 2013

Zhaga Consortium Publishes Book 2 Interface Specification for LED Light Engines

Some examples for Zhaga compliant products Zhaga has published its second interface specification, as part of its mission to enable the interchangeability of LED light sources. Products carrying the Zhaga logo are already available from various manufacturers. Read more »

White Paper | Standardization + Regulation | Jan 10, 2013

SEMI's LED Standards Committee HB-LED Standard Published

After the formation of the high-brightness light-emitting diode (HB-LED) Standards Committee in November 2010 the committee was working hard on HB standards. The committee is happy to announce that it now has approved its first standard, SEMI HB1: Specifications for Sapphire Wafers Intended for Use for Manufacturing High Brightness-Light Emitting Diode Devices. Developed by the HB-LED Wafer Task Force, SEMI HB1 defines and specifies the physical geometry of 150 mm diameter sapphire wafers used in HB-LED manufacturing. HB1 covers dimensional, wafer preparation, and crystallographic orientation characteristics, as well as the appropriate measurement methods. The document was approved by the HB-LED Committee during the North America Fall 2012 meetings, recently completed procedural review and will be published soon. Read more »

White Paper | IP, Reports & Roadmaps | Jan 03, 2013

DoE Releases CALiPER 2012 Year in Review Report

The CALiPER 2012 Year in Review report contains several graphs like this one showing overall test results since 2006 The CALiPER program has tested more than 500 products since its inception in 2006, revealing a variety of performance trends, holding manufacturers accountable for claims, and identifying concerns that limit adoption. Over the past six years, the LED marketplace has changed substantially; previously relegated to niche status, LED products are now a viable alternative in many product categories and market share is expected to grow rapidly. Starting in 2012, Summary Reports focus on a single product type or application. Read more »

White Paper | Technology | Oct 10, 2012

Fan Efficiency, An Increasingly Important Selection Criteria

A typical performance plot of a 120mm size axial fan with curves for both airflow and efficiency How important is fan efficiency in the selection of a cooling system? Selecting a cooling fan is no longer about airflow and noise. The true test for a design engineer is the understanding that by selecting an efficient cooling fan system savings in cost of ownership can be realized. NMB Technologies Corporation, a Minebea Group Company, has released a new white paper on that issue. Read more »

White Paper | Standardization + Regulation | Oct 03, 2012

EMerge Alliance Releases Version 1.1 of Occupied Space Standard

Progress continues toward integrated standards for DC microgrids in buildings SAN RAMON, CALIF. (October 2, 2012) – The EMerge Alliance – an open industry association leading the rapid adoption of safe direct-current (DC) power distribution standards for commercial buildings – today announced it has updated the EMerge Alliance Occupied Space standard, the first application platform model for the utilization of low-voltage DC power in commercial interiors. The EMerge Alliance Occupied Space standard creates an integrated, open platform for power, interior infrastructures, controls and a wide variety of peripheral devices to facilitate the hybrid use of AC and DC power within commercial buildings. Version 1.1 includes several important updates to voltage limits, recommended cable sizes and other requirements to assist companies developing products when using the standard. These changes are backwards compatible and maximize the interoperability and efficiency of EMerge Alliance Registered products. Read more »

News-Spot | IP, Reports & Roadmaps | Aug 03, 2012

Rubicon Technology Patent Allowed for In-situ Crystal Orientation

Rubicon Technology, Inc., a leading provider of sapphire substrates and products to the LED, semiconductor, and optical industries, today announced that the United States Patent and Trademark Office (USPTO) has allowed Rubicon’s patent application entitled, “Intelligent Machines and Process for Production of Monocrystalline Products with Goniometer Continual Feedback.” The patent covers Rubicon’s equipment and process developed to perform in-situ orientation of its sapphire crystals within the various fabrication tools used by the Company. Read more »

News-Spot | IP, Reports & Roadmaps | May 02, 2012

Power Integrations Reports Verdict in Patent Case Against Fairchild Semiconductor

Power Integrations announced a verdict reached in the company's 2008 patent-infringement lawsuit against Fairchild Semiconductor. After a three-week trial in the U.S. District Court for the District of Delaware, a jury found that Fairchild infringes two Power Integrations patents. The infringement findings cover approximately 75 Fairchild products. Read more »

FEATURED

LumiTop 4000: Comprehensive Optical Wafer Testing for μLEDs

LumiTop 4000: Comprehensive Optical Wafer Testing for μLEDs Instrument Systems offers a unique camera-based measurement solution for μLED wafer testing that generates 2-dimensional, pixel-resolved optical analyses within given cycle times. The LumiTop 4000 has a resolution of 12 MP and can detect the smallest of defects and inhomogeneities on the wafer. ... Read more »

FEATURED

Lumileds Maximizes Field Usable Lumens: New LUXEON HL2X LED

Lumileds Maximizes Field Usable Lumens: New LUXEON HL2X LED Lumileds introduces the LUXEON HL2X, the ideal choice for roadway lighting and sports lighting fixtures with the highest flux and efficiency in an industry standard package. "With 318+ lumens at 700 mA and 85°C, LUXEON HL2X delivers more 'field usable lumens' for optical engineers to work with. ... Read more »

EDITORIAL

Australian Associated Press Recently Wrote: Red Light Could Improve Over-40s' Eyesight

Australian Associated Press Recently Wrote: Red Light Could Improve Over-40s' Eyesight A small LED torch that emits deep red light could help improve declining eyesight, scientists have said: A study by University College London, involving a small sample size of 24 people, has shown that staring at long wavelength light for three minutes every day can "significantly improve vision" ... Read more »

EDITORIAL

Signify Invests to Broaden Its UV-C Lighting Portfolio for Professional Disinfection

Signify Invests to Broaden Its UV-C Lighting Portfolio for Professional Disinfection Signify, the world leader in lighting, is increasing its UV-C lighting production capacity and expanding its UV-C product portfolio. The company is leveraging more than 35 years of expertise in UV-C lighting to address the growing global need for the disinfection of air, surfaces and objects. Read more »