PWM小功率多路输出开关电源的设计

摘要

开关电源的高频化电源技术发展的创新技术，高频化带来的效益是使开关电源装置空前地小型化，并使开关电源进入更广泛的领域，特别是在高新技术领域的应用，推动了高新技术产品的小型化、轻便化。另外开关电源的发展与应用在节约资源及保护环境方面都具有深远的意义。

为此本论文以反激式高频开关电源为设计方向而展开，对高频变压器的认知及所注意的问题，其中包括磁芯损耗、绕组损耗、温升以及磁芯要求。高频单端反激式变压器是本文的中心内容，其核心参数设计许多，具体内容正文中有详细介绍。其次是控制电路的设计，首先我们要对PWM集成控制器原理的有所了解，在此基础上保护两种控制模式分别是电压模式和电路模式。同时采用UC3842开关电源集成控制器，它是一种高性能的固定频率电流型集成控制器，能很好地应用在隔离式单端开关电源的设计，其最大优点是外接元件少，外电路装配简单等。开关电源的质量指标应该是以安全性、可靠性为第一原则，所以，在同一开关电源电路中，设计多种保护电路的相互关联和应注意的问题也要引起足够的重视。

通过相关文献及实现数据的带入进行验证，最终确定出此设计方案是可行的，设计达到最初的效果。

关键词：单端反激式变压器；PWM集成控制器；UC3842集成控制器；多路输出。

PWM small power multi-output switching power supply

Abstract

Switch power source high frequency power supply technology development of innovative technologies, the benefits is to make high frequency switching power supply device with an unprecedented miniaturization, and causes the switching power supply to enter the more widely, especially in the high-tech fields of application, promote the high-tech products of miniaturization, light. In addition the power switch in the development and application in saving resource and protect environment has profound significance.

In this paper, the flyback switch power supply for the design direction and spread out, the high frequency transformer of cognitive and attention problems, including the core loss and winding loss, temperature rise, and core requirements. High frequency single end flyback transformer is the central content of the article, the core of many specific parameter design, detailed in the content of the text. Followed by the design of the control circuit, first of all we have to understand the principle of PWM integrated controller, based on the protection of two kinds of control modes are the voltage mode and circuit model. While the use of UC3842 switching power supply integrated controller, it is a kind of high performance fixed frequency current-mode integrated controller, can be well applied in isolation type single end switching power supply design, its biggest advantage is less external components, simple external circuit assembly. Switching power supply quality indicators should be based on safety, reliability as the first principle, so, in the same switch power supply circuit, protection circuit design a variety of interrelated and should pay attention to the problem should cause enough attention.

Through the literature and data to verify, eventually determine the design scheme is feasible, the effect of initial design to achieve.

Key words: single end flyback transformer; PWM controller; UC3842controller; Multiple output。

目录

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