LED driver: lighting applications are still cool heat

High threshold lighting technology

LED lighting into the key technology of ordinary civilian areas will take time - by foreign monopoly

LED lighting has shown great potential, but the level of development in different areas of application is not balanced, therefore, different areas of the driver circuit market performance is uneven. Hangzhou Silan microelectronics power supply and power driven product line general manager Wu Jianxing said in an China "electronic newspaper" interview with reporters, LED lighting market development the main obstacle is the high cost, so LED lighting will be the first in a relatively insensitive to the cost of the field, such as landscape lighting, street lighting and lighting; general manager of Hangzhou Mao Power Semiconductor Technology Co. Ltd. and Hangzhou R & D center remote MPS Ren also expressed similar views, he believes that due to the high price, the application of LED lighting is still concentrated in the municipal engineering, a large scale into ordinary civilian areas may take 3 to 5 years.

A Morimi semiconductor power and portable product of global sales and marketing director Zheng Zhaoxiong also told reporters expressed the company attached to the LED lighting market, he said: "A Morimi semiconductor will give full play to the company in the field of management power of technical expertise and manufacturing expertise, provide LED for automotive lighting, commercial lighting, outdoor lighting and general lighting a variety of applications such as driving scheme. "

Technically, the application of lighting on the LED drive circuit also put forward higher requirements. The Fairchild PCIA lighting department director Li Zaipeng told reporters: "LED lighting drive circuit is more and more focused on stable brightness and power conversion efficiency, the pursuit of higher efficiency, higher integration and smaller size. "System, high power LED lighting technology relates to electrical, optical and thermal, mechanical and other disciplines, chairman Dr. Huang Wei Wuxi Crystal Kay Technology Co., told reporters:" from the realization method of view, LED lighting technology includes power devices and high voltage process technology, integrated circuit design, power and thermal management advanced packaging and optoelectronic integrated technology and other advanced manufacturing technology. Compared with the developed countries, our country started late in the field of lighting LED drive and the foundation is weak, lack of core technology with independent intellectual property rights. "Huang Wei said," the current for driving high power LED IC chip technology is mainly monopolized by several European semiconductor company, especially the application of 25W to 100W power range area road lighting and output power of more than 100W of the main road lighting, due to the need to use a flyback converter with isolation, so only a few several companies have mastered the technology. According to Huang Wei introduction, for resistance TRIAC dimmer incandescent lamp is difficult to CFL and LED capacitive electric light dimming, which has been the bottleneck of LED driving technology, crystal Kai technology developed to 110V ~ 260V AC lighting application's first domestic AC/DC high voltage chip, to accurately adjust light town a number of innovative technology, breaking through the bottleneck and achieve the incandescent lamp, can directly replace the high energy consumption to achieve LED free with resistive TRIAC dimmer to use.

Indoor and outdoor applications have their own characteristics

Street lighting needs to adapt to the harsh environment indoor applications should consider compatibility

In the application of LED lighting, there are obvious differences between the outdoor and indoor lighting. According to Wu Jianxing introduction, street lamps using AC power supply, the need to convert AC into DC, and then achieve constant current control. The output power of the lamp, the working environment is bad, need to consider the extreme temperature conditions, taking into account the road maintenance cost, product reliability requirements are very high; compared with lighting, indoor lighting power is small, the working environment is relatively good, but the cost is relatively sensitive, must also be considered with the original lighting interface on compatibility, the volume of the product also has strict requirements.

Ren Yuancheng from the perspective of product structure explained to reporters of outdoor and indoor lighting LED driver circuit differences, he said: "the street lighting uses three level architecture, namely'PFC (power factor correction) + isolation DC/DC converter + constant current buck converter. Usually the first two level design by the power supply manufacturers, is a relatively independent power supply, to provide a stable DC voltage to the lamp, whereas the third stage LED system designed by the manufacturers themselves, constitute a whole and lamps. The third stage circuit, due to the severe LED, requires a high conversion efficiency. Indoor lighting usually adopts single stage, although whether PFC is not yet conclusive, but the industry has been generally assumed that if the traditional incandescent bulbs replaced all LED on power grid harmonic pollution can not be discounted, so PFC is necessary; the incandescent lamp and fluorescent lamp has often dimmer is matched. LED lamp replacement must be dimmer, and the original work; in addition, according to the specific application, driving circuit can be isolated, can not isolate. "

Extend life to be hard

To solve the problem of heat dissipation is to extend the life of the key LED thermistor assume the responsibility to protect LED devices

LED product life is also very concerned about the issue of consumers, and even the view that the driver circuit is a short board so that LED products become short-lived". Zheng Zhaoxiong told reporters: LED product itself has a long service life, if the reliability of the drive circuit is low, it will affect its service life, thereby affecting the life of the entire lighting system. It is not difficult to provide high reliability drive circuit, but it is difficult to maintain high reliability, but also reduce costs. Therefore, designers choose the appropriate LED driver