Design And Stability Analysis Of Buck DC-DC Converter With Peak Current Mode Control

As the electronic devices spread, Switching Power Supply is been more and more wildly used. It is featured with high efficiency and small size, it can suit for many application for its various topology. The stability of Switching Power Supply is guaranty for the system which used it to work stable, so the research of stability of Switching Power Supply is meaningful.This paper presents a Buck DC-DC Switching Power Supply with Peak Current Control. The input voltage is ranged from 6V to 32 V, maximum current load is 4.5A, output voltage is 5V, it work at 500 KHz switching frequency and can be synchronized by outside clock, the maximum work frequency can be 1MHz.To study the stability of Switching Power Supply, we must build its small-signal model. Firstly, this paper introduces main methods to modeling Switching Power Supply, include Basic Modeling Method, State-Space Averaging Method and Averaged Switch Method. Based on this methods, this paper also introduced the models of Peak-Current Control Switching Power Supply, include Ridley’s model, CoPEC model and Bryant’s model, talked about the basic idea and modeling progress of these models. This paper present the system structure, system work principle and peripherals selection. Completed the design of some key modules of system, give module circuits and talked about work principle of these circuits in detail.The circuits were simulated with Hspice based on BJT process. At the same time, this paper talked about the small signal stability with Ridley’s model, obtain the system loop transfer function. Based on analysis the poles and zeros of the transfer function, make up a proper compensation method to make sure the stability of system loop. Then, make the simulation of whole system to verify its work under all work situation, all the specifications are achieved.