A Design And Study Of A Green Mode's Switching Power Supply

With the development of science and technology,the demands of the Switch Power Supply for Communication & Consumer Electrical Products are growing rapidly,and the Environment Friendly is the development direction of Switch Power Supply. Currently the Switch Power Supply is widely used in the variety of electrical equipments, so it is necessary to further study the working principle, increase the reliability, and own the environment friendly for Switch Power Supply, these studies have very important realistic significance. The studies of Green Mode Switch Power Supply include two concepts, one is the efficient energy storage, second is the reducing disturbance and pollution of the grid and the peripheral equipments from the Switch Power Supply.This paper mainly research the stability precision, dynamic performance, stability margin for the fly back Switching Power Supply of note book PC, and the working principle of Switch Power Supply is further researched in Matlab and PSPICE. According to its performance indicators and the characteristics, a kind of Environment Friendly Switch Power Supply with good frequency characteristic, high linearity, lower output ripple voltage was designed. This paper mainly presents the design of the circuit modules included: PFC, transformers, PWM control technology, synchronous rectification and control loop design, etc. The linear transfer function model of loop control of Switch Power Supply was deduced by the theory, and improved the compensation circuit feedback network by analyzing the placement of the zero-pole, in order to make the system meet three objects: (1) Open-loop transfer function gain is large enough to improve the stability; (2) In order to prevent the -40dB/dec gain slope of the phase of circuit changing rapidly, the system's closed loop gain curve in the vicinity of the gain crossover frequency should be -20dB/dec; (3) Ensure the open-loop phase margin large enough and the transfer function's phrase margin is not less than 45°. Finally, PCB was designed completely, the performance figures of experimental circuit were validated by chroma6000ATS. And simulation results show that the Switching Power Supply meets the requirement of performance indicators.