Research And Design Of LED Driving Power Supply And Control System

As a new generation of semiconductor solid state lighting source, with its advantages of high luminous efficiency and long life, LED lighting has become one of the best choice in the replace of traditional way of lighting.However, due to the low efficiency of LED drive power and the fluctuations of output current, sometimes its life can not match the life of the LED light source, so those shortcomings have seriously limitted the promotion of LED lighting. Therefore, the development of a high efficiency, high power factor and long life LED drive power will make a great significance in the LED lighting.So, after mastering the conventional LED drive power design methods and analysising the development situation of LED, we designed a driver power supply with 85V-265V/50Hz voltage input and 24W power output.Firstly, on the basis of the working principle of power factor correction (PFC), by comparing the advantages and disadvantages of half-bridge converter, full-bridge converter and flyback converter, the PFC was designed by flyback toplogy. According to the demand of the LED driver power system, the main circuit of converter, clamp circuit, EMI filter and feed back circuit have been analysed and designed; the DC/DC conversion uses the Buck topology as constant current source, based on LM3404HV with high pressure resistance and a PWM dimming interface.Secondly, a dimmable lighting system was designed by using Atmegal28, a microcontroller of AVR family as the core design of the LED drive power control system based on the completion of the LED drive power. The LED lighting control system will be connected to the light intensity sensors, both conventional dimmer and the failtures of conventional dimmer applied to LED driver are explained and the solutions are developed and discussed, according to the changes of light in the external environment to adjust LED brightness to achieve the purpose of the intelligent control, and the entire LED intelligent lighting system is completed.Finally, the performance parameters of the. entire system is tested and analyzed under the laboratory background. The test results show that the LED power driver works well and the dimming system runs stable, we provide the main part of the LED drive power and the simulation waveform in the last part of this thesis.