单片开关电源的分析-微电子学与固体电子学专业论文.docx

单片开关电源的研究 单片开关电源的研究 PAGE PAGE VI Abstract Nowadays, electronic systems become more and more popular with the development of electronic science and technology. As the most important part of electronic systems, power supply is becoming more and more versatile. And it has been developing towards the trend of light, more flexible, and more efficient. Single-chip switching power supply are produced especially for switching power supply, which integrate PWM and high voltage MOSFET together , and have perfect protection function. Designing low power switching power supply with such integrated circuits can decrease parts count and cost, increase reliability. Nowadays the applied series adjustable regulator is linear regulator of continuous control. The traditional series regulator, it s adjustable transistor always working at amplifier area, the electric current is continuous, the disadvantages of regulator are low efficient and capability in overload. The paper introduces basic structure of switching power supply and type of power converter. In this paper, a new PWM monolithic switched power supply circuit is researched. The author firstly introduces the basic theories about PWM then under the guidance of methodology of integrated circuits design the author has designed the total circuit. The author simulates functions of every module. Firstly, the principle and characteristics of this Single-chip switching power supply are analyzed. Second, the external circuits of system include several parts, these are an oscillator circuit, Datum potential source, protection circuit, PWM comparator electric circuit, error repeater circuit, SCHMITT trigger circuit, eight frequency dividing circuits. According to the design requirements , the detailed analysis of the several parts is presented, calculation of the values of the parameters and selection of the components are provided. At last, output voltage wave and the analysis of the whole electrical character are given. The