Reliability Modeling And Simulation Analysis Of Flyback Switching Power Supply

As the upstream component of the electronic system,the switching power supply plays a vital role in the normal operation of the overall system,so its reliability design has received more and more attention.However,in the current electronic system,there is a phenomenon that product reliability design and circuit function performance design are out of phase,which seriously restricts the reliability and quality level of electronic products.In view of the above situation,this paper selects the widely used flyback switching power supply as the research object,and designs a digital control flyback switching power supply.Based on the EDA software platform,the circuit is reliable by establishing multi-parameter influence device model and functional reliability simulation technology Integrated design of sex and performance.This paper first introduces the working principle of flyback switching power supply and the basic theory of functional reliability analysis.On this basis,it collects various parameter characteristics of main components,and further proposes the concept of first-order parameters,second-order parameters and third-order parameters.By comparing the advantages and disadvantages and applicability of various modeling methods,using a variety of modeling methods,the multi-parameter reliability model of the main components and the digital logic model of the multi-pin STM32 are established and verified.During the period,the unique characteristics of each device were considered and the specific methods were made to make the characteristics of the model more perfect,such as the derating characteristics of the resistor,the nonlinear temperature characteristics of the capacitor,the crystal frequency and the load capacitance characteristics related to the front circuit.Thermal characteristics of MOS tubes and timing characteristics of minimum systemsIn the process of model establishment,a custom fault parameter variable is established.By implementing parameter variable changes in the FMEA module,batch injection and automatic injection of faults are realized.Therefore,the model in this paper has a higher degree of fit and a better fault injection flexibility.Then,a digital control flyback switching power supply is designed,which mainly includes circuit design calculation of control chip selection,input loop design,output loop design,switching tube calculation and selection,RCD pulse absorption loop calculation and so on.A variety of reliability simulation analysis was carried out for the designed switching power supply.The stability of the designed circuit was optimized by combining the simulation results.The overall output voltage distribution at different temperatures before and after optimization is compared.It is proved that the circuit reduces the sensitivity to the environment after optimization and improves the overall out-of-tolerance condition.the final calculation of the circuit output through the robust performance indicators has a high performance reliability.Finally,the physical production of the designed power supply was completed,and the flyback switching power supply experimental platform was built for output testing.Through the detection and control of the power running state of the host computer and the failure of the FMEA,the experimental results are compared with the simulation results.The results verify the accuracy of model building and circuit simulation under standard environment,and further verify the accuracy of functional reliability simulation method.