A Kind Of Dynamic Self-powered Monolithic Integrated Ac-dc Chip Design

As an important building part of switching-mode power supply(SMPS), smart power ICs or power management(PM) ICs have been developing rapidly and attracted more and more attention because of the widespread use of SMPS. The huge demand of consumer electronics also accelerates the development of PM ICs. Among the varied PM ICs, the monolithic AC-DC switching-mode regulators characterized as highly precise output, low-cost, high efficiency and highly reliable are widely used in AC-DC power converters.The main goal of this thesis is to develop a monolithic AC-DC regulator targeting at small power flyback converters with DSS(Dynamic Self-Supply). The main features of the monolithic AC-DC regulator can be outlined as follow: internal high-voltage current source provides DSS function, no need for auxiliary winding; internal soft-start circuit overcomes the power-up overshoots; frequency jittering effectively reduces EMI interrupt; skip cycle mode lowers switching loss when output load is light; over voltage protection circuit, over current protection circuit, over load protection and thermal shutdown are also integrated on the chip.The main job of this thesis could be outlined as follow: Firstly, this paper describes the research background of this thesis and the fundamentals of SMPS; Secondly, it introduces a SMPS simulation technique based on PWM Switch model. Using the simulation technique, the main framework and the specification of the proposed AC-DC regulator are developed. The practical realization of the proposed AC-DC regulator is given in accordance to the specification. Finally, the main job of this paper and special features of the AC-DC regulator are summarized and reviewed.