摘 要：开关电源因其具有稳压输入范围宽、效率高、功耗低、体积小、重量轻等显著特点而广泛应用与航空、通信、交通等领域。随着高频技术、谐振技术的发展，全桥移相软开关电源广泛应用于在低压大电流开关电源领域、因此有必要对其进行研究。

传统的硬开关技术具有开关损耗大,感性关断电压尖峰大,容性开通电流尖峰大且电磁干扰严重等缺点。而本文所选用的软开关技术，具有效率高，开关损耗小等特点。

本设计在对硬开关功率变换电路缺点分析的基础上，提出了软开关变换电路，并对软开关的定义、分类、发展以及控制策略进行了归纳和总结。本文设计的开关电源是采用基于UC3875的ZVZCS PWM软开关技术。与芯片UC3842相比，芯片UC3875既能实现零电压启动，又能实现零电流启动，提高了开关电源的工作效率，和开关电源的安全性能。93792

Abstract：Switching power supply is widely used in aviation, communication, transportation and other fields because of its wide range of input voltage, high efficiency, low power consumption, small size and light weight。 With the development of high frequency technology and resonance technology, full bridge phase shifted soft switching power supply is widely used in the field of low voltage and high current switching power supply, so it is necessary to study it。Traditional hard switching technology has many disadvantages, such as large switching loss, high peak voltage, high capacitive current and serious electromagnetic interference。 The Soft switching technology used in this paper has the characteristics of high efficiency and low switching loss。 Based on the analysis of the disadvantages of the hard switching power converter circuit, the soft switching circuit is proposed, and the definition, classification, development and control strategy of the soft switching are summarized。The switching power supply designed in this paper is based on UC3875 ZVZCS PWM soft switching technology。 Compared with UC3842 chip, chip UC3875 can achieve zero voltage start, and can realize zero current start。 Improve the efficiency of switch power supply, and the security performance of the switch power supply。源C于H优J尔W论R文M网WwW.youeRw.com 原文+QQ752-018766

Keywords：Switching power supply，soft switch，UC3875

目   录

1  绪论……………………………………………………………………………4

1。1课题研究的背景、目的和意义………………………………………………4

2  软开关技术……………………………………………………………………5

2。1软开关的定义…………………………………………………………………5

2。2软开关的分类…………………………………………………………………6

2。3软开关的具体应用……………………………………………………………6

3  设计原理与总体电路设计……………………………………………………7