The power factor of the LED driver power supply will reach more than 95%

With the progress of science and technology, lighting tools and the way of changing the user for lighting show, illumination uniformity, color standards and energy efficiency play needs more and more high, at this stage, the most watched when non LED lighting is lighting the bright younger generation. With a light bulb and fluorescent lamp replacement, embedded lights, streetlights and parking lights, work lights (lighting lamps, cabinets), landscape lighting, building lighting, billboard text circuit general lighting market as an example, is expected to 2012, LED lighting market will grow to $1 billion 308 million, a compound annual growth rate of 17.4%. Therefore, LED general lighting has become a hot market.

However, there are still some problems in the application of LED lighting market, including LED consistency, life testing, especially power supply and drive system specifications and other issues to be resolved. The requirements of LED driver power supply include high efficiency, high power factor, high current control accuracy, high reliability, safe isolation, EMI standard, small size, low cost, etc.. It is worth noting that the latest energy star standards for more than 5W of LED lighting products, power factor requirements (PFC) must be greater than 0.7, so as to further achieve the purpose of energy conservation.

Power input system requirements vary

Analysis of the cost structure of LED lamps, heat dissipation components accounted for about 30% of the power supply system accounted for 20%, accounting for part of the assembly, LED components accounted for the largest proportion, up to more than 45%. In the various parts of the LED lamp, the power module shoulder the important task of saving energy. The current LED lighting power supply input system on the market can be divided into two categories, one is the constant current control module for AC power input system and the back-end, such products include freezing cabinet lights, indoor lighting, street lamp, desk lamp, MR16, AR111 etc.. Another type of AC power supply direct input system integration AC/DC converter and constant current circuit, such products include E27 and GU10 bulb type LED lamp, PAR lamp, T5 and T8 LED lamp, etc..

According to Kai Yu technology senior manager He Shaojia, the first power supply design in addition to should choose constant voltage power supply is better efficiency, constant power control of the power supply module is according to the characteristics of products with better efficiency of power supply design. The utility model has the advantages of power supply in front of AC/DC, such as switching power supply, DC adapter and a constant voltage power supply, high selectivity and safety authentication scheme, thus reducing the threshold of design.

The second kind of power supply design is due to the integration of the AC/DC circuit and constant current circuit, the main difficulty lies in the power factor, power efficiency and safety aspects of the design, there are some difficulties. In this regard, the industry said that different power AC (DC) LED (AC-DC) lighting applications suitable for different topologies of power supply. For example, when the power is less than 80 W, the flyback topology is the standard choice, and in the application of high efficiency, the resonant half bridge dual inductor plus single HB (LLC) is the preferred.

High power conversion efficiency for the goal

It is understood that welcome LED lighting topology of super efficiency in popular in recent years, the industry is hoping to power in relatively low level (<50W) to provide more than 90% efficiency, and such high efficiency needs to be reached in the new topology, such as topology structure to replace the resonant half bridge flyback topology such a structure, can make full use of zero voltage switching (ZVS) advantage.

From the application of the power level, AC-DC power supply LED general lighting applications include low power, medium power and high power and other types. Low power applications typically range from 1 to 12W in power, with medium power ranging from to 40W; high power applications are typically higher than 40W. Overall, the main challenge facing the drive power LED lighting industry is LED drive should be converted to challenge higher efficiency, especially in the high-power LED drive, because all is not as light output power is dissipated as heat, power conversion efficiency is too low, will affect the energy saving effect of the LED play.

First of all, in the 1W to 8W low power LED general lighting, typical applications such as G13, GU10, PAR16, and embedded lights, etc.. The input voltage range of this kind of application is between 90 and 264V, and the constant current output current includes 350mA and 700mA, the performance requirement is 80%, and the short circuit protection and overvoltage protection are required. In 8W to 25W LED general lighting application requirements and programs, are divided into no PFC and PFC.

For the absence of PFC, 8W to 25W AC-DC LED lighting for typical applications such as PAR30, PAR38 and recessed lights. In such applications, the input voltage required for 85~135 Vac or 185~264Vac (or universal input), performance requirements of more than 80%, with short circuit and open circuit protection protection function, constant current output current of 350mA, 700mA and 1A in different current. In the requirements of PFC 8W to 25W LED AC-DC lighting, the typical application is also PAR30, PAR38 and embedded lights. The input voltage specification for this kind of application is 90 to 264 Vac, the performance requirements of the, 350mA, 700 mA and 1A constant current output, provide short circuit and overvoltage protection, power factor requirements higher than 0.9. As for 50W to 200W LED general lighting for street lighting and high-power regional lighting, can be used for 50W-150W or 100~200W power range of different LED programs.

Active power factor adjustment is more than 95%

In view of the LED lighting power supply drive demand, in the constant current driver, the main push T6316 technology, it is a 4 channel