Implementation Of An Improved Current Mode SEPIC Converter

With the growing utilization of portable device and the rapid process for computer, communication constantly actuates the development of the technique of switching power supply. The research of DC-DC converter served as the core of SMPS, are becoming a hot-spot currently. The technology of DC-DC converter integrates several techniques including theory on the DC-DC converter, Integrated Circuit (IC) design, power semiconductor device technology and so on.Firstly, based on the system architecture, the principle and key technology of DC-DC converter are introduced and analyzed. Pulse-width modulation (PWM), pulse-frequency modulation (PFM) and PWM-PFM modulation are introduced in detail afterwards. On the basis of the comparison of control methods, this paper give an improved current-mode control method by adding multi-feedforward.Based on the in-deep study of the interrelated technique of the DC-DC SEPIC converters, this thesis presents a design scheme of the switching regulator of current-mode PWM SEPIC converters operating. The project takes advantage of the control scheme of current mode PWM with multi-feed-forward. According to the demands of application, a specification is put forward and the working principles of the converter are also explained. Considering the key factors of the circuit design, the structure of the converter is defined, and then the design procedure of relevant primary functional blocks are presented, with the simulation by Hspice. Lastly, a typical application of circuit is introduced.According to the result of the overall chip simulation, the response speed of the improved converter has increased significantly.