Design And Implementation Of Active Clamp Power Supply Based On STM32F334

With the development of China’s economy,switching power supply is usually used in complex high-performance systems.Active clamp positive excitation power supply is widely used in medium and small power applications because of its advantages of simple topology,high efficiency,low cost and high reliability.At present,there are many problems in the market,such as high temperature drift,general system monitoring and management,low dynamic response and high cost.Therefore,it is of great engineering value and significance to discuss and design an active clamp positive excitation power supply based on STM32.First of all,based on a brief analysis of the current situation of digital power supply at home and abroad,this paper summarizes the development trend of digital power supply,according to the market demand for low cost and high performance of small and medium power digital power supply,and determines the design and implementation of STM32F334 based on the active clamp positive excitation power supply design object.Secondly,the paper introduces the working principle of the basic positive excitation power supply and active clamp positive excitation power supply in detail,analyzes the three reset modes of the positive excitation power supply in detail,and makes a comparative analysis of the two active clamp modes of the positive excitation power supply,and determines that the upper active clamp is the reset mode and the positive excitation is the power supply extension.Thirdly,the STM32F334 chip is briefly introduced.The main components of the input filter rectifier circuit,the main power conversion circuit and the output filter rectifier circuit of the active clamp positive power supply are designed and selected.In this paper,the control circuit of active clamp positive power supply,including the definition of power supply identification signal,voltage and current protection circuit and sampling circuit are designed in detail.Then,in this paper,STM32F334 is used as the control core,the driving signal of the power switch tube is configured,the PI compensation loop,duty cycle compensation mode,feedforward compensation loop,gain detection method and overcurrent protection mode are designed,and the software design flow chart and part of the program are given.Finally,based on the design parameters,the software simulation is carried out,the experimental prototype is made and the experiment is completed.The maximum efficiency of the prototype reaches 91%,the output voltage rises steadily when the power is started up,the output voltage of the steady-state load is within ±1%,the output voltage of the dynamic load is within ±5%,and the over-flow voltage protection is normal,which meets the design requirements.