用PWM信号控制LM317稳压电源

用PWM信号控制LM317稳压电源(任务书,开题报告,论文10000字)
摘要
21世纪，我们身边的电子设备也在飞速发展，这使得人们的生活变的更加的便利。然而任何电子设备都需要直流电源供电。但传统电源输出电压单一、体积庞大、效率低且散热困难。而稳压电源比传统电源相比具有体积小、输出电压范围可调、稳定性高等特点，被广泛应用于科研领域、学校实验室等地。虽然稳压电源十分普及，但他的使用范围还是被限制了。一是必须依赖电网供电，大大降低了电源的机动性，很多时候不能为应急通信提供支持；二是虽经整流滤波，但仍会有残余的交流成分干扰。
与传统开关电源相比，PWM控制的开关电源具有提高功率因素和抑制谐波能力的优点[2]。本文主要介绍了如何用脉冲宽度调制（PWM）信号控制LM317稳压电源。本文从最基本的原理出发，详细地介绍了电路设计思路、电路原理，元器件参数的选择，最后，对设计电路做仿真测试并分析数据。
关键词：PWM  稳压电源  LM317占空比

Controlling LM317 Regulated Power Supply with PWM Signal
ABSTRACT
In the 21st century, electronic devices around us are also developing rapidly, which makes people's lives more convenient. However, any electronic device needs power supply. But the output voltage of traditional power supply is single, its volume is huge, its efficiency is low and its heat dissipation is difficult[10]. Compared with the traditional power supply, the regulated power supply has the characteristics of small size, adjustable output voltage range and high stability, and is widely used in scientific research fields, school laboratories and other places. Although voltage stabilized power supply is very popular, its use is limited. First, it must rely on the power supply of the power grid, which greatly reduces the mobility of the power supply and can not provide support for emergency communications in many cases. Second, although it is filtered by rectifier, there will still be residual AC component interference.
This paper mainly introduces how to control LM317 voltage stabilized power supply with pulse width modulation (PWM) signal. In this paper, starting from the most basic principles, the circuit design ideas, circuit principles, the selection of components parameters in detail, finally, the design of the circuit simulation test and analysis of data.
Key words：PWM  Regulated power supply  LM317 Duty
 

目录
摘要    I
ABSTRACT    1
第一章绪论    2
1.1 背景    2
1.2 稳压电源发展史    2
1.3 PWM研究现状    3
第二章电路原理介绍    5
2.1 第一部分：占空比可调的PWM信号发生器原理    5
2.1.1555定时器    5
2.1.2 由555定时器组成的多谐振荡器    8
2.1.3 占空比可调的方波发生器    9
2.2 第二部分：由LM317组成稳压电源的原理    10
2.2.1 LM317    10
2.2.2 LM317典型应用电路    15
2.2.3LM317组成稳压电源的原理    15
2.2.4 LM358    17
第三章电路模型设计    18
3.1设计方案构想    18
3.2电路整体设计    18
3.3电路工作原理    19
3.3.1由555定时器搭建的占空比可调的多谐振荡器电路原理：    19
3.3.2由LM317组成的直流稳压电源电路原理    20
3.4 电路具体参数计算    22
第四章模拟仿真    24
4.1 对PWM信号发生器进行模拟    24
4.2 对整个电路进行模拟    27
4.3 仿真结果分析    33
4.4 模拟总结    33
参考文献    35
致谢    37