With the increasing people’s awareness of energy saving and environmental protection, the industry is increasingly concerned about the environmental impact of energy consumption. In the way of a variety of energy consumption, according to statistics, up to 20-22% of the electricity used for lighting. Improve the efficiency of energy use for lighting applications even further reduce their energy consumption, help reduce carbon dioxide emissions, creating a greener world. Therefore, energy-efficient lighting is becoming a focus of the industry to compete.
From the application field of view, lighting covering different categories of residential lighting, industrial lighting, street lighting, and restaurants, retail and service sectors in lighting. From a power rating of view, in addition to low-power lighting, including high-power area lighting, typical applications such as column lights (bollards), wash the wall lights (wall wash), the external walls of lamps (wall pack), tunnel lighting, street lights, parking field lighting and public safety, industrial and retail lighting outdoor lighting, and low dome light (low bay), high dome (high bay), freezer / refrigerator and garage interior lighting.
High-power area lighting, there are many challenges, such as lamps may be difficult to close, light failure, may pose a security problem, and outdoors there are a variety of extreme environmental conditions. In addition, it can not be ignored, the existing light source (used in high-power area lighting such as metal halide lamps (the MHL), high pressure sodium (HPS), linear fluorescent lamp (LFL) and compact fluorescent lamps (CFL) ) there are a lot of limitations, poor color rendering, such as high pressure sodium (CRI of about 22), a typical metal halide lamp fixtures loss higher (40%) and from start to experience to the full brightness light-emitting time may take up to 10 minutes, the cold temperature performance of the linear fluorescent, compact fluorescent lamps start has been slower.
The other hand, with high brightness white light emitting diode (LED lights) is continuous improvement in performance and cost, more and more for high-power area lighting, and not have the advantage of the traditional light source, such as giving each lumens of light less power consumption, control the direction of better color, better quality, environmentally friendly, and open and close it easier to control, easy to automatically detect the ambient light, thereby changing the brightness; In addition, the reliability of LEDs is also better. help to reduce maintenance costs and total cost of ownership.
The main function of the LED driver in a variety of conditions of low flow, and to protect the LED from the impact of the surge and other fault conditions, and provide some level of security, to avoid (electrical and / or mechanical) shock and fire. For area lighting applications, the outdoor environment to give the LED driver to bring the temperature challenge, and may need to withstand 277 Vac, 347 Vac, or even 480 Vac geometric standard higher voltage AC input voltage.
Area lighting applications, LED drivers may also need to comply with the standards of some of the power factor or harmonic content. Requirements such as the harmonic content of the EU’s International Electrotechnical Consortium (IEC), IEC61000-3-2 standard lighting device power exceeding 25 W (C), which is equivalent to the total harmonic distortion (THD) less than 35%; However, in line with IEC61000-3-2 Class C harmonic content requirements does not necessarily mean that the power factor (PF) is higher than 0.9. Some markets, such as the United States is usually PF higher than 0.9 and THD of less than 20%.
Many regions of lighting applications in outdoor, may be subjected to a variety of strict temperature conditions, so that the overall service life are affected. The overall system design service life have a major impact, so the use of internal heat, a lower loss of energy-efficient LED driver is very important, and to drive the LED heat source in the design of thermal isolation, thus increasing system reliability.