Articles & Interviews

White Paper | Technology | Oct 08, 2013
Two-Switch Flyback Solution for LED Street Lighting
Two-Switch Flyback Solution for LED Street Lighting 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 »
Interview | Products, Materials + Tools | Nov 06, 2013
Lighting Innovation - Dialog Semiconductor Introduces New smarteXite Technology Platform for Intelligent LED Lighting
Lighting Innovation - Dialog Semiconductor Introduces New smarteXite Technology Platform for Intelligent LED Lighting Dialog Semiconductor plc, a provider of highly integrated power management, AC/DC, solid state lighting and short-range wireless technologies, announced its smarteXiteTM platform, enabling a new generation of highly flexible, programmable LED driver ICs for smart lighting applications. SmarteXite, based on fully configurable logic, is the first LED driver technology to directly and easily support wireless connectivity, light sensor control and allow easy integration into lighting control systems. Arno Grabher-Meyer and Siegfried Luger, both from LED professional, talked with Stefan Zudrell-Koch, Business Development Manager at Dialog Semiconductor, about their new technology platform. Read more »
Commentary | Jan 20, 2014
"Beyond LM Testing - A New Metric for Quality over Lifetime" by Thor Scordelis
"Beyond LM Testing - A New Metric for Quality over Lifetime" by Thor Scordelis In a recent blog post, the United States Department of Energy’s Jim Brodrick noted that solid-state lighting standards and testing methods “may not be glamorous, but they’re essential for the success of any technology, and SSL is no exception.” Certainly, this is true with respect to lumen quality, and for many years, the LM-80 standard, used to measure lumen maintenance of LED packages and modules, has sufficed. However, with the growing adoption of LED technology has come higher customer awareness and expectations. “Good enough” isn’t good enough anymore. Read more »
Technology | Feb 03, 2014
Target Group-Adequate Lighting of Shop and Retail Areas – New Retail Study by Zumtobel
Target Group-Adequate Lighting of Shop and Retail Areas – New Retail Study by Zumtobel n a laboratory study conducted by Zumtobel and Gruppe Nymphenburg it has been possi-ble for the first time to measure people's affective responses to various lighting scenarios in shops on an empirical basis. In the process, the lighting preferences of seven different groups of customers were analysed using a neuropsychological target group model. The findings of this study will help to develop lighting concepts for retail, to present goods per-fectly and to increase the customers' sense of well-being, thus making them stay in the shop longer. Read more »
Tech-Talks Bregenz | Jun 16, 2014
Tech-Talks BREGENZ: Martina Paul, General Secretary, CIE (Article published in LpR #43)
Tech-Talks BREGENZ: Martina Paul, General Secretary, CIE (Article published in LpR #43) With the rise of LEDs as the future lighting technology, the relatively stable lighting industry faces many changes and challenges. One of the main challenges is the ever increasing speed of transitions, something already seen in the semiconductor business. Standardization organizations are facing similar challenges. On the one hand they should define standards that will last as long as possible and on the other hand the standards need to be as clear and precise as possible. Martina Paul, Secretary General of the most important standardization body, the International Commission on Illumination (CIE) was invited to the Tech-Talks BREGENZ to discuss these topics. Read more »
Smart Lighting + IoT | Resources | Tech-Talks Bregenz | Controls | LpR Article | Sep 12, 2014
Tech-Talks BREGENZ - Walter Werner Werner Mgmt. Services, CEO
Tech-Talks BREGENZ - Walter Werner Werner Mgmt. Services, CEO The transition from traditional light sources to solid-state light sources has also affected lighting controls. Nowadays we talk about smart lighting, human centric lighting and software dominated lighting concepts. Dr. Walter Werner from Werner Management Services, a highly experienced lighting controls expert, discussed the major trends in lighting controls with LED professional, as part of the Tech-Talks BREGENZ series. Read more »
Resources | LpR Article | Tech-Talks Bregenz | Market | SSL
Tech-Talks BREGENZ - Dietmar Zembrot, LightingEurope, President
Tech-Talks BREGENZ - Dietmar Zembrot, LightingEurope, President Rapidly growing technologies and emerging market trends in solid-state lighting encourage new innovations largely driven by applications and technological developments. Dietmar Zembrot, President of LightingEurope and Managing Director of TRILUX Group, shared his insights on changing value chains and business models, Europe’s competitiveness and the main driving forces for current SSL technologies. Read more »
Resources | LpR Article | Tech-Talks Bregenz | Measurement | Jan 09, 2015
Tech-Talks BREGENZ - Prof. Jiangen Pan, Everfine, Founder & CTO
Tech-Talks BREGENZ - Prof. Jiangen Pan, Everfine, Founder & CTO With ever-increasing demands on measurement equipment, it is becoming essential to meet user needs by providing combined solutions, which address optical, electrical and thermal issues. Prof. Jiangen Pan CEO, Founder and Chief Scientist at Everfine Institute of Optoelectronics, provided valuable insights on new compact solutions for LED measurements, his views and contributions towards global standards and how he works in his “thinking laboratory”. Read more »
Tech-Talks Bregenz | Jan 30, 2015
Tech-Talks BREGENZ - Prof. Mehmet Arik, University of Ozyegin, Turkey
Tech-Talks BREGENZ - Prof. Mehmet Arik, University of Ozyegin, Turkey Thermal management is an ongoing challenge and a topic of continued research and innovation. Prof. Mehmet Arik from the University of Ozyegin, Istanbul, also known as the ‘Edison of the 21st Century’, discussed core thermal issues and new innovative solutions, trends in cost reduction, packaging and how we can learn from electronics to achieve better thermal management of the system as a whole. Read more »
LpR Feature | Technologies | Mar 12, 2015
Practical Estimation of Measurement Times in Goniospectroradiometry and Goniophotometry
Practical Estimation of Measurement Times in Goniospectroradiometry and Goniophotometry The angle-dependent characterization of LED modules and lights often raises the question about typical measuring times. In particular, the comparison of spectrometer-based systems with photometer-based systems is of considerable interest here. Dr. Günther Leschhorn, product manager for spectroradiometers and SSL measurement equipment from Instrument Systems GmbH, considers different measurement set-ups in a study and makes recommendations for various application cases. Read more »
White Paper | Technology | Mar 30, 2015
TRIAC Dimmable, Isolated LED Driver with High Power Factor Needs No Opto-Isolators
TRIAC Dimmable, Isolated LED Driver with High Power Factor Needs No Opto-Isolators As environmental concerns over traditional lighting in-crease and the price of LEDs decreases, high power LEDs are fast becoming a popular lighting solution for offline applications. In order to meet the requirements of offline lighting - such as high power factor, high efficiency, isolation and TRIAC dimmer compatibility - prior LED drivers used many external discrete components, resulting in cumbersome solutions. By Wei Gu Applications Engineering Section Leader at Linear Technology demonstrates how new solutions reduce complexity while improving performance. Read more »
Tech-Talks Bregenz
Tech-Talks BREGENZ - Daniel Doxsee, Nichia Europe, Deputy Managing Director
Tech-Talks BREGENZ - Daniel Doxsee, Nichia Europe, Deputy Managing Director Nichia is arguably the company with the longest history of manufacturing white LEDs. Recently, however, new competitors especially from China, have started challenging Nichia’s market share. Nichia’s role in strategic and technical solid-state lighting issues and its past, present and future were discussed with Daniel Doxsee, Nichia Chemical Europe’s Deputy Managing Director. Read more »
Research | LpR Article
A Self-Compensation Approach for Maintaining the Chromaticity Coordinates of Phosphor Converted LEDs Upon Temperature Variations
A Self-Compensation Approach for Maintaining the Chromaticity Coordinates of Phosphor Converted LEDs Upon Temperature Variations Solid-state light sources for general illumination applications are currently becoming more and more popular. Maintaining chromaticity coordinates over temperature is a challenge. Wolfgang Nemitz, Franz P. Wenzl, Susanne Schweitzer, Christian Sommer, Paul Hartmann from the Institute for Surface Technologies and Photonics at Joanneum Research, and Paul Fulmek and Johann Nicolics from the Institute of Sensor & Actuator Systems of the Vienna University of Technology investigated this issue and propose a promising new solution. Read more »
Tech-Talks Bregenz
Tech-Talks BREGENZ - Ewing Liu, Everlight, Technical Marketing Manager
Tech-Talks BREGENZ - Ewing Liu, Everlight, Technical Marketing Manager LED manufacturers have different strategies and approaches for their product portfolios depending on from which business they are originated. Everlight has a very long experience in optoelectronics as packaging company. Accompanied by Christopher Keusch, Director of Lighting Business EMEA, Ewing Liu, Technical Marketing Manager at Everlight, talks about about the background of the company, the worldwide strategies and upcoming techologies. Read more »
Research | LpR Article
Direct Current (DC) Supply Grids for LED Lighting
Direct Current (DC) Supply Grids for LED Lighting Since many alternative energy sources as well as electronics and controls technologies are based on DC current, DC grids have been investigated more intensely in the last decade. DC grids with a centralized AC/DC conversion have proven to be advantageous in server farms. While LED lighting is also a DC current related technology, an obvious choice would be to use DC grids for them. Prof. Eberhard Waffenschmidt from the Cologne University of Applied Science in conjunction with Philips Research presents the results of an office building DC lamp system installation with photovoltaic (PV) support. Read more »
Leading Article | LpR Article
2015 Year of (LED) Light
2015 Year of (LED) Light The advent of artificial lighting has revolutionized society. 2015, in particular, will go a long way in establishing solid-state light-based technologies as a vital area of innovation for the 21st century. Dr. Amrita Prasad from LED professional gives an overview of the technical evolution of (LED) lighting and how this may have triggered UNESCO’s decision to make 2015 the Year of Light. Read more »
Research | LpR Article
LED Office Lighting for Improved Well-Being and Performance
LED Office Lighting for Improved Well-Being and Performance The influence of artificial light in industry has been a topic of conversation for a while now but opportunities provided by LED lighting have made this subject even more important. Katrin Möller, Junior Researcher at the Competence Center Light, her research partners, Vincent Grote from the Human Research Institut, and Birthe Tralau from Zumtobel Lighting, investigated the effects of LED and fluorescent lamp lighting on human well-being and performance in an office environment, in a comparative laboratory study. Read more »
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