| With the advent of increasingly tense energy crisis, depletion of traditional fossil fuels, sustainable development and green development got more and more attention.Because of its high luminous efficiency, low power consumption, long life and other advantages, LED is developing rapidly for the "green light" and becoming the fourth generation lighting system after incandescent lamps, sodium lamps and fluorescent.Simultaneously with the development of semiconductor technology, high-power LED has been widely used in all types of lighting situations and LED dimming control technology is also growing rapidly. Therefore, the design of high efficiency and high performance LED driver for the development of LED industry has an important significance.It shows a detailed analysis of the background of LED lighting development and the significance of this subject in this paper, simultaneously it does an in-depth theoretical analysis of technology of the LED driver power supply including the common topologies in drive and the main technical parameters, rectifier circuit, antielectromagnetic interference, clamp protection circuit, optocoupler feedback circuit,power calibration techniques and step-down constant current source LED dimming technology that can influence LED driver circuit. According to these theoretical foundations, it designs a 50 W LED constant current drive circuit that can be controlled by PWM dimming based on a UC3844, HV9910 chip. In this circuit,power factor calibration function of the driver power is achieved by a single-stage PFC flyback circuit, the current output of LED constant current source is realized,LED dimming function is controlled by the PIC microcontroller and at last a reasonable and effective solution is raised on related issues. |
