| Just like human's heart, power supply is indispensable in all kinds of electronic equipment. There are two DC regulated power supply which are used commonly currently. One is linear power supply,the other one is switching power supply(SPS). It is named as high efficient and energy saving power supply. It stands for the direction of the development of power supply. Of course it becomes mainstream product in dc regulated power supply. In this paper, an offline AC/DC pulse width modulation (PWM) controller is presented. The design is based on the CSMC 0.5μm BCD process. According to actual application, function blocks are divided. After the design and simulation of circuits, the design of layout is fulfilled.In this thesis, the history and tendency of SPS is given firstly. Then, the topology,key technologies and application system of dc/dc are introduced in succession. The overall framework of the PWM controller is based on the current control mode. And then the design and simulation based on Hspice of sub circuits are completed, including bandgap voltage reference, oscillator, interior power-supply, soft-start, energy saving, skip cycle, current comparator, voltage monitor, over temperature protection and driver.Through deeply studying on CSMC 0.5μm BCD process,the design of layout based on Cadence is accomplished. Finally some experience about BCD layout design is shared.By adding several circuits, such as the protection of over voltage,under voltage, over temperature and so on, the chip can work stably. At the same time the efficiency of the light load is enhanced with the help of skipping cycle technology.This design belongs to the project named as"The research of new power chips with information management function"which is aimed at growing people with venturesome and innovative qualities for Suzhou. This chip has been send out ,but the results are waited for testing and verifying. If it succeeded,HuaXin Micro-electronics company will make it a product.
|
PDF Full Text Request