A High Power, High Efficiency White Led Constant Current Driver Chip Design

Due to the shortage and urgent requirement of energy conservation, each country is currently promoting the green energy-saving lighting application. White LED lighting is becoming a new generation of illumination source in 21st century because of Pocket size, low dissipation, long life, fast response, high conversation efficiency of electro-optical transformation and environmental protection. The power drivers, an essential part of the LED, is greatly expanding its market. The key factors of designing a power driver include high efficiency, high power factor, safety isolation, conforming to EMI requirements, high current control accuracy, high stability, small size and low cost, which necessitate the research on high power LED driver.The idea and frame of this thesis are as follows:Firstly, after Analyzing the characteristics of white LED, it is pointed out that constant current drive is necessary; By comparison and analysis of three kinds of constant current drive as well as three kinds of control mode, and according to actual requirements of circuit design, switching hysteresis current control mode based on inductor is chosen to drive LED in constant current.Secondly, several sub-circuits carried by the author are analyzed, designed and simulated, including reference circuit, current sense circuit, and under voltage lockout circuit.Last but not the least, the function and performance of the whole circuit are simulated and validated, and the results satisfy the original objects, which prove the correctness of the theory analysis and feasibility of the design. In addition, the tape-out is carried out after the validation of the layout design.