摘要：本文针对传统的线性电源电能转换效率低，无法满足功率密度越来越大的电子产品，设计了一款小功率的开关稳压电源。输入端利用EMI滤波电路来最大化降低干扰波。在功率转化部分，采用单端反激电路，加入钳位保护电路，保护电源不会因MOS管截止时产生的尖峰电压而损坏。在控制部分负反馈回路中，采用KA431配合光耦PC817对采样取得的电压信号进行隔离化处理，反馈给PWM控制芯片，然后PWM提前输出，高/低电平，对MOS管截止/导通进行调控，从而达到输出稳压。本文采用美国PI公司推出的DPA-Switch单片开关电源芯片，围绕这个芯片设计出外围电路，多路输出稳定的直流电压,分析了开关稳压电源的功率损耗主要原因，并分析几种可行性的措施去降低功耗。43444

毕业论文关键词:开关稳压电源；PWM技术；EMI滤波；单端反激

Low-power Switching Power Supply Design

Abstract: In this paper, the traditional linear power supply electric energy conversion efficiency is low, can not meet the power density of more and more large electronic products, designed a small power switch power supply. The input end uses the EMI filter circuit to reduce the interference wave. In the power conversion section, a single ended flyback circuit is adopted, and the clamping protection circuit is added to protect the power supply from being damaged due to the spike voltage caused by the cut-off of the MOS tube. The control part of the negative feedback loop, using KA431 with optocoupler PC817 isolation to the sampling of voltage signal processing, feedback to the PWM control chip, then PWM ahead of output, high / low level, of the MOS pipe cut-off / conduction regulation, so as to achieve output voltage. The PI Corporation in the United States launched the DPA switch monolithic switching power supply chip, the external circuit around the chip design, multiple outputs stable DC voltage, analyzes the switch regulated power supply power loss, the main reason, and analyze some feasible measures to reduce power consumption. 

Key Words: Switching regulated power supply;PWM technology; EMI filter; Single ended flyback 

目    录

摘要 1

1.绪论 2

1.1研究的背景和意义 2

1.2开关电源研究现状 2

2.开关电源电路的工作原理 3

2.1开关电源的基本概念 3

2.2开关稳压电源的控制方式 3

2.3开关稳压电源电路原理框图 4

3.开关稳压电源的子电路 4

3.1 EMI滤波电路 4

3.2开关电源功率转换电路 5

3.3钳位电路 7

3.4反馈电路 7

4.小功率开关稳压电源的应用 9

4.1在风力发电机控制器方面的应用 9

4.2单片开关电源芯片的选择 9

4.3小功率开关稳压电源的设计 11

4.4软件仿真 13

4.5开关稳压电源功耗的降低 14

5.结论与展望 15

5.1结论 15

5.2展望 16

参考文献 16