A Design Of AC-DC Converter Based On The Primary And Secondary Side Integrated Control And Soft Switching Technology

With people's increasing demand for power,AC-DC converters have been rapidly developed,and are widely used in various electronic equipment adapters,daily lighting power supplies,home appliance power supplies,and so on.There are many types of AC-DC converters,and they are moving towards high efficiency,high power density,high output accuracy,small weight,and high reliability.Among them,flyback switching power supply has been chosen as the research object of this article for the advantages of high efficiency,small size,light weight,reliable electrical isolation between input high voltage and output low voltage,etc.,but it also brings high switching loss and a risk of simultaneous conduction in the primary and secondary side,which should be limited in the field.So an AC-DC converter design based on the original secondary-side integrated control and soft switching technology is proposed.Soft switching technology can reduce switching loss caused by switching power supply and improve light load efficiency.The original secondary side integrated control scheme can avoid the risks of simultaneous conduction in the primary and secondary side,so that the system can work safely in continuous conduction mode and improve the heavy load efficiency.In this paper,a flyback topology is selected for the AC-DC converter.After comparing the characteristics of the flyback converter under different operating conditions,a control method that can ensure high efficiency in the full load range is confirmed.With soft switching,integrated control of the original and secondary side and synchronous rectification technology,the system is efficient and reliable after optimization.The specific control adopts the analog control method with higher ease of use and lower cost.Based on the comparator,operational amplifier and various logic circuits,it is suitable for many power supply occasions.This article uses SMIC 0.18 um CMOS process to simulate and layout the designed IC.It verifies the core functions such as the original and secondary side integrated control,soft switching,synchronous rectification technology,and performance such as load shedding and ripple.The efficiency of this scheme was tested,analyzed and optimized.The results show that the design results are in line with the expected goals,and the efficiency is significantly improved after the introduction of each technology.