Reach And Application Of Driving Circuit For LED

As" greenhouse effecf"of the global getting worse, the level of the ocean continuesly rising, the sources of one-time energy, such as coal, petroleum, gas, becoming more short, LED lighting which is a new type of semiconductor solid-state light source, is becoming more and more popular。In addition of its unique features, such as protection of environment, energy saving, long life, durable, small size, fast response, convenient regulation, the advantages of rich colors, it quickly becomes the hottest new technology of energy-saving and environmental protection. Because of the developing of semiconductor technology and the reducing of cost, it is wildly used as indicative lights, traffic lights, flashlights, miner's lamp, electronic display screen, LCD backlight, auto lights, lights of landscape. So,the development of LED driving technology becomes current focus.The developing history of LED is described, and the electrical characteristics of LED is analyzed in this paper. The main requirements of LED driving is got,and several common types of driving power is also studied, Especially study on DC-DC topological stucture of switching power supply and feedback control models. So,the practical value of switching power supply is recognized. According to the actual characteristics of switching power supply, the HV9931 and UC3842 chips are chosen. Finally,two kinds of constant-current source which for white LED has been constructed successfully.The constant-current source based on HV9931 is Single-Stage Power Factor Correction Converter. The cost is reduced. The number of component is also decreased. Its efficiency is improved. The technique has a large practical value for LED Illumination.Another low cost switching power supply of single-ended flyback is based on UC3842 which has 8 pins.It is easy to debug.At last, the prospect and insufficient of the solution was described.