Design Of High Transient Response Digital Switching Power Supply Based On Sliding Mode Fusion Algorith

With the variety of electronic products and their application demand gradually increasing,people’s requirements for their performance continue to improve,among which,the power supply field has been widely concerned.In the field of power supply,analog power supply plays a vital role in various applications.Because of its mature research and anti-interference ability,circuit complexity and other aspects,there are still difficult to break through the bottleneck,so digital power supply has gradually become the mainstream research direction of people.This dissertation constructs a kind of digital step-down switching power supply based on FPGA from the simple digital power supply.In this dissertation,the working principle and common control mode of Buck circuit are introduced at first.The mathematical model of switching power supply is obtained by analyzing the small signal and working state.Then,the parameters of specific components are designed according to the design requirements of power supply.Secondly,the hardware circuit of FPGA and switching power supply is built,the work flow of FPGA is briefly described,and the simulation evaluation test of acquisition module and driver module in the hardware circuit is completed.After that,it is discretized on the basis of traditional PID control and sliding mode control,and a control system which integrates the two control algorithms is designed.The system combines the characteristics of PID control,simple structure,fast response and sliding mode control,so as to improve the dynamic performance and stability of the output voltage.The Verilog code of each control link is simulated and verified by modelsim.In addition,this dissertation uses PLL IP core,counting and jitter methods to design a high resolution,low frequency DPWM generation module,through the code simulation waveform calculation and analysis to verify its accurate modulation performance.Finally,a simulation closed-loop system is constructed on the matlab/ simulink platform,and the modulation effects of the three control methods on the switching power supply are compared respectively.The results show that the fusion control algorithm has good effects in reducing overshoot,stabilizing output and resisting disturbance.This design on the hardware platform finally finished the test,under the48 V input set,output voltage stability in 12 V,the transient waveform of the start time of just 1.04 ms,super am a value of 0.6 V,the steady state ripple is 4%,and the load disturbance has the characteristics of low volatility,rapid response,meets the design requirements of this article,so as to verify the feasibility of fusion control algorithm.