The main function of the LED driver is the lower limit of the flow in a variety of conditions , and to protect against surges and other LED fault conditions, as well provide some level of security , to avoid shock and fire ( electrical and / or mechanical methods ) . For area lighting applications, LED outdoor environment will bring the temperature of the drive challenges , and may need to withstand 277 Vac, 347 Vac or 480 Vac or higher geometric standard voltage AC input voltage.
Area lighting applications, LED drivers may also need to meet certain criteria related to power factor specification or harmonic content . As the EU's International Electrotechnical Union (IEC) of the IEC61000-3-2 standard for power exceeding 25 W lighting equipment ( Class C) harmonic content requests, equivalent to the total harmonic distortion (THD) is less than 35% ; However, in line with the class IEC61000-3-2 C harmonic content requirements does not necessarily mean the power factor (PF) is higher than 0.9 , while in some markets ( such as the U.S. ) generally requires more than 0.9 PF and THD less than 20 %.
Many outdoor area lighting applications , it may undergo various stringent temperature conditions , so that the overall service life is affected. The overall system is designed to have a major impact on life, so use less internal heat loss less energy-efficient LED driver is very important, and in the design you want to drive LED heat source and heat isolation , thereby enhancing system reliability.
LED lighting control can become more intelligent. Traditional street lights with timers or ambient light sensor from the main control . The use of power line communication (PLC) or wireless control technology, can provide a highly flexible LED area lighting control, such as the light output level of centralized control time-based , light level sensor based traffic control , and based on the detection of people, vehicles regulated activities downtown lighting, both car and pedestrian street lighting . LED intelligent control technology in more than save energy , it also does not compromise security . Typical applications like intelligent dual brightness level of lighting, such as parks , gas stations, roof, parking lots , stairs and refrigerators, cabinet lighting support as needed to adjust the brightness level of lighting. LED can be turned on and off instant , can be easily adjusted according to the lighting operation or activity level in these applications , such as providing a 20% -40 % of the luminance level when no activity is detected , and upon detection of the event 100% brightness lighting. This is conducive to a lot of additional power consumption savings .
