1、 1 摘 要 随着电子技术的高速发展，电子系统的应用领域越来越广泛，电子设备的种类也越来 越多，电子设备与人们的工作、生活的关系益密切。任何电子设备都离不开可靠的电源， 它们对电源的要求也越来越高。特别是随着小型电子设备的应用越来越广泛，也要求能够 提供稳定的电源，以满足小型电子设备的用电需要。 开关电源具有高频率、高功率密度、高效率等优点, 被称作高效节能电源。由于开关 稳压电源具有这些优点，基于这个思想设计了一个 12V 的低功率开关稳压电源，以满足小 型电子设备的供电需要。 本设计主要介绍了开关电源的发展历程，未来发展趋势，以及开关电源的优缺点。本 设计采用典型的反激拓扑开关电源结构设计
2、形式，以 UC3842 作为控制核心器件。采用场 效应管作为开关器件，其导通和截止速度很快，导通损耗小，这就为开关电源的高效性提 供保障。 其次，控制电路以 UC3842 芯片为控制核心，采用闭环控制模式，实现系统的稳压和 限流。另外，对控制系统的过电流保护、过压保护、过热保护电路等保护电路进行了设计。 关键词：关键词：PWM；UC3842；开关电源；MOSFET 一种新型开关电源的设计 2 Abstract With the high-speed development of electronic technology, the application of the electronic s
3、ystem is more and more extensive, as well as the variety of the electronic equipment. The relation between electronic equipment and our daily life is getting much closer day by day. As we know any kind of can work depending on some kinds of power supply which would have to be improved to meet the ne
4、ed of electronic equipment. Especially the popularization of the small-scale electronic equipment, it requires the steady power supply in order to meet the demand of small-scale electronic equipment. The switch power supply has such advantages as high frequency rates, strong power, high efficiency, and was called the energy-efficient power. In this way the switch power supply shown here is on 12V, in order to meet the needs of such power supply for the small-scale electronic equipment. The d
