Design And Implementation Of High-power LED Driver

LED luminaires are becoming increasingly popular in many applications, especially in outdoor situations such as roadway, area and site lighting. The LEDs used in these luminaires maintain up to 70 percent of initial lumen output for 20 years or longer, as compared to traditional lamp sources. They are also mercury-free and offer reduced light pollution due to more precisely controlled light direction through LED placement and optics optimization. Even light distribution improves the outdoor lighting function and creates a better and safer environment overall.The main work of this paper is to complete the design of a quasi-resonant flyback LED constant current driver, with high power factor and high conversion efficiency. Contents of this paper include the following aspects:1. Background on the issue and the status of the development of LED drive power are briefly introduced, and LED electrical characteristics are analyzed, then, LED driver power supply design requirements are proposed. The current mainstream LED driver power supply topologies are described and compared, and then the driver circuit architecture of the driver designed in this paper is determined.2. The relationship between power factor and harmonic content are analyzed, power factor correction circuit of different operation modes are analyzed and compared, The control mode of critical conduction mode power factor correction circuit are analyzed, and then structure of the power factor correction circuit and related parameters computing are given.3. Analyzing the running process of flyback converter at discontinuous conduction mode in the state of ideality and actuality, simulating respectively. On this basis, the Quasi-resonant(QR) flyback topology working principle is obtained, and then the implementation circuit is simulated, in plus, structure of the Quasi-resonant(QR) flyback convert circuit and related parameters computing are given.4. Showing the LED drive power designed in this paper, analyzing waveforms and data of the key point, and carrying out summary and prospect.