| In recent years, with the development of power electronic technology, power system has become an important part of the power electronics field, and become the research focus in the people. Its small size, light weight, high efficiency, high reliability advantages is becoming more and more of attention.Several typical topology of switching power supply are analyzed and compared, through the contrast analysis, finally will focus on the flyback type this topology.On the choice of the flyback type topology structure principle, work in this thesis. Further selection switch power modulation mode and control mode. According to the actual demand to determine the overall design scheme of power supply, power supply of the whole circuit diagram is given, and its working process is described.The sub circuit design process of system carried on the thorough analysis, including the design process of the power transformer and winding method, power level circuit composition analysis and involve switching tube, the selection of rectifier and loss calculation. On the basis of the complete power level circuit design, choose UCC1802chip control circuit is designed. The chip pin definition is introduced and its own features, and then start the power supply of its periphery circuit, oscillator circuit, current sampling and current limiting circuit, voltage feedback and amplifying circuit, protect circuit chip. Finally on the rectification filter circuit design.Using Saber software circuit simulation analyses and authenticates the whole system design. On the basis of theoretical analysis and simulation results to develop power supply circuit performance tests, the actual test problems puts forward improvement measures, the experimental results show that the circuit of the main technique index and function have reached the design requirements, such as good stability, switch power supply ripple is small, the overall efficiency higher characteristic, illustrates the feasibility of the design. |
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