The Design Of Multiple-Output Switching Power Supply

Power is an indispensably part to make sure the electrical equipment work in a normal, reliable and stable way. Among of them, switching power become a research hotspot because of it’s advantages such as high efficiency, energy saving and portable. A complete switching power supply system mainly composed of input circuit, switching converters, transformers, output circuit and control circuit, it will convert AC input power into DC Power required for power electronic devices.Based on in-depth analysis of switching power supply working principle and characteristics, according to the design requirement, complete the design of a single-ended flyback eight outputs switching power supply, which provide reliable operating voltage for power board and control board in the servo system.The power input AC voltage ranged form165V to265V, the eight DC voltage output are±5V/2A and±14V/0.2A separately,3channel15V/0.2A and15V/0.5A, and the frequency of switching power supply is66kHz.The paper first analyze the development trend of domestic and foreign high-frequency switching power supply, do the research of switching power supply’s major part working principle and design method, introduce the common DC-DC converter topology structure in switching power supply,as well as the modulation mode of switching power supply and the work style of high frequency transformer, determine the system’s overall program; second design each module of the circuit in detail, and take the current-type control chip TOP246Y and high-frequency transformer as the core, adopt EMI filter circuit, clamp circuit, the control chip peripheral circuit, feedback circuit, protection circuit and the output filter circuit and so on to achieve eight channel stable output; this article focused on the use of area product (AP) to determine the magnetic core type of high-frequency transformer, and the selection steps of primary and secondary winding parameters; finally choice, design and calculate the circuit parameters of the switching power supply reasonable, and get the overall schematic diagram of the circuit.On the basis of the circuit schematic diagram, the modeling and simulation of transformer by software SIMetrix/SIMPLIS verified the rationality of the transformer design parameters; introduced the PCB routing rules of switching power supply, produced the PCB circuit board, and assembled prototype, and tested the prototype at last. The accuracy of the output voltage of prototype tested was less than3%and the ripple coefficient was less than1%, the overall test results of prototype showed that the indicators of power met the design requirements, and could keep the output voltage stable.