Design And Implementation Of A Magnetic Feedback Switching Power Supply

The development of modern electronic technology is making dramatic changes in the production method and the life style of the humanity.From industrial automation equipment to television,computers,tablets,smartphones,wearable devices,etc.All of this makes our life more convenient.The circuit structure is very different according to the difference of circuit function.No matter which kind of system are inseparable from the support of power technology.It can be said to be the heart of all circuit systems.It provides energy supply and security for the circuit.Under this background,the research of power technology has become an important topic in the electronic technology.The development of power technology has a long history.Many kinds of power have been developed for more than a century.The mainstream technology is linear power supply and switching power supply.By contrast,switching power supply is favored by people,because of the advantages of high efficiency and small size,so people began to pay more and more attention to the research of switching power supply.The design of switching power supply a complex and systematic project,which includes many aspects such as power device design,circuit structure design,feedback control technology,thermal design and so on.At the same time,power electronics today are facing increasing demands for miniaturization,improved efficiency,and reduced cost,extended range of Voltage-Conversion Ratio(VCR),improved dynamic performance,improved system stability and reliability,and so on.Focusing on these issue,new technologies are being applied to optimize these problems.technology of switching power supply has been continuously optimized and innovation.Combined with the project requirements,aiming at the optimization of the area and reliability of the switching power supply,a high-frequency and high-reliability switching power supply has been designed.In order to achieve the miniaturization of switching power supply design,the paper brings forward two major measures.The first is using single switch flyback topology.The second is increase the switching frequency from conventional 100kHz?300kHz to 450kHz.Flyback topology circuit structure is simple,which can reduce the number of devices used.What's more,higher switching frequency will reduce the size of the passive components.Thus the area of power supply can be reduced.In order to improve the circuit reliability,this paper uses the magnetic feedback circuit instead of the conventional optocoupler feedback circuit.Compared to the traditional optocoupler feedback circuit,the magnetic feedback circuit had better tolerance of temperature and can show better operating characteristics in harsh temperature environment.In addition,this paper also optimizes the start-up circuit by using the Darlington start-up circuit instead of the traditional RC start-up circuit.Using the Darlington startup circuit,the charging speed of the chip's power capacitor is faster helps reduce start-up time.In the design process,to save the cost of production and shorten the design cycle.The SABER simulation software is used to simulate the function of the circuit.The circuit layout is made after the function verification is passed.Under the ANSYS workbench 18.2 software platform,the thermal analysis of the circuit is carried out by establishing the thermal model of the key components of the circuit.It can provide the basis for the rational selection of the layout process and layout optimization of the circuit.The purpose of enhancing the heat dissipation capacity of the circuit is achieved.In the end,the model is made and debugged according to the design scheme obtained by the simulation.And verify the correctness of the circuit design,complete the design of the overall circuit.