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LED energy-saving and environmental protection advantages make it more widely, but its tunnel lights, street lamps and other lighting areas to promote the application process, there are still problems to be solved. Wherein the LED circuit protection and thermal protection when abnormal heating problems limit the number of LED series, which will increase the number of LED constant current driver. For this problem, the paper studied a way to achieve the LED and the temperature of the overvoltage protection circuit of the chip, to increase the number of LED series. In addition, for LED constant current driver problem, the LC series resonant circuit implementation using open loop constant current LED driver, and verified with the drive power protection function of the chip. The main contents are: First, to establish an LED optical model, through simulation, research-driven current on the LED luminous efficiency for the protection and guidance of LED drive power supply design. According LED voltage and LED forward current characteristic curve and relative luminous efficiency curve, using the curve fitting method, the respective curves obtained expressions using Expression Design LED optoelectronic model. Using this optical model, through simulation, analysis of the five kinds of drive current to the LED luminous efficiency, and finally the experimental study and prove the correctness of the simulation model. After the LED of a way to realize the overvoltage protection circuit and the temperature of the chip, which can increase the number of LED series, thereby reducing the number of constant current drive power. This paper describes the working principle of protection of the chip, according to the working principle of the design can be integrated protection circuit and protection circuit analysis, the circuit design method and basis. The text of the protective circuit simulation analysis, results show that the design can achieve the overvoltage protection circuit, open circuit and temperature protection. The circuit configuration according to the design, built with discrete analog circuit components for experiments, the experimental results are consistent with the simulation analysis proved the correctness of the protection circuit. Finally, the LC series resonance circuit design of LED open loop constant current driver, which can be used in a distributed DC bus structure, can improve the reliability of power supply, and LED longevity MingXiang match. Principle of open-loop constant current paper carried out a detailed analysis, the open-loop constant current conditions. Also given open-loop constant current drive switching frequency, resonant inductor-capacitor and transformer ratio design basis. Under this basis for circuit design and simulation analysis, and resonant inductor and transformer theoretical calculation, design experiment experimental verification, the experimental results are consistent with the simulation proved the correctness of analysis and design.
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