Research And Develop Of The Low Power LED Switching Power Supply

Illumination is an important aspect of energy consumption, it accounts for 20%of total energy consumption, so the research of green lighting is getting more and more attention of everyone.LED occupies the growing market because advantage of environmental, long life, high efficient, the amount of LED enterprises is increasing, the government also enacts laws about the LED domain to make it develop fast and healthy. With arrival of the LED green lighting age, the product of LED light will be used more and more extensive, which will lead increasingly strong business competition between LED enterprises, the LED product become lighter, thinner, smaller and more efficient in the predictable future.This paper design the low power LED switching power supply and give the scheme of main modules based on the analysis of various of switching power supply topological structures and the LED’s characteristic. Detail as follows:First elaborate various switching power supply topological structures and development tendency of the switching power supply, next analyze the optic-electric characteristic of LED, accord which design a single-end fly-back power suit for medium and small power LED, then analyze theoretical and design the circuit of input protection, EMC, clamp, feedback.Secondly, this paper analyze in detail, about the technology of APFC and PPFC, present the PFC scheme based on SA7527 which work on critical conduction mode, the value of PFC reach the expected objective.High-frequency transformer is the critical component of low power consumption LED switching power supply, which decides the efficiency of energy conversion, this paper analyze the working principle and influence factors in detail, the influence main contain the proximity effect and trend-skin effect based on which design the transformer.At last build up the circuit based on the analysis and design above, and test the critical nodes, the result shows that every parameter reaches the expected goal, and it verify the correctness of theoretical analysis.