Design And Realization For Switching Power Supply Of Low Ripple Based On TOP258

With the advent of aerospace, computer and robot technologies. Relying on its advantages, Switching Power Supply(SPS) has received an unprecedented development. Meanwhile, DC power supplies for experiments, audio electronics, measuring instruments, high-precision sensors and military products etc. have a restrict constraint for ripple’s amplitude of output power, which poses a primary drive for the development of low ripple SPS. It can be foreseen from the strategy’made in China 2025’that smart factories composed of robots will be quite common in the future. To make robots become the main force of industrial production early, the demand for more intelligent, accurate and portable devices will be stronger. Therefore, the development of a low ripple SPS is deliberate.In this dissertation, the main circuit topology and working principle of SPS are analyzed detailedly, supression methods for low frequency ripple, switching ripple, common mode interference, ripple resulting from control block are discussed. A flyback SPS with five-channel voltage outputs is designed and realized.Design:According to design requirements and combining the ripple suppression methods, a solution based on TOP258 to develop a low ripple flyback SPS is determined. Each module of flyback SPS is analyzed and designed for the consideration of reducing ripple, the modules include protection circuit, rectifier circuit, RCD circuit, control circuit, transformer, secondary output circuit, feedback loop, etc. where design of transformer and the feedback loop are specially introduced. At the same time, the output accuracy of other channels of conventional SPS are not desired except the main channel. Therefore, a DC-DC voltage stabilizing chip-MCP16311-E/MS is added to other channels. At last, the schematic of the whole circuit is provided.Realization:Based on the schematic, following the rules of designing PCB of SPS, the PCB design of SPS is finished on Altium Designer platform. After soldering and debuggering, the properties like efficiency, accuracy and the output ripple level of the prototype board are measured. The results show that all properties are in consistent with design where the outputs of other channels are more superior compared with the main channel.To shorten the development cycle in the future, analysis for the properties above have been made, we can see that the overall design of the SPS is reasonable, but, the efficiency, accuracy and ripple factor can still be improved.