模拟电子技术课程设计 模板

直流集成稳压电源设计

姓 名

学 号

院、系、部 电气工程系

班 号

完成时间 2014年6月21日

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※※※※※※※※※ 2012级

模拟电子技术课程设计

摘 要

直流稳压电源一般由电源变压器，整流滤波电路及稳压电路所组成。变压器把市电交流电压变为所需要的低压交流电。整流器把交流电变为直流电。经滤波后，稳压器再把不稳定的直流电压变为稳定的直流电压输出。本设计主要采用输出直流稳压构成集成稳压电路，通过变压，整流，滤波，稳压过程将220V交流电，变为稳定的直流电，并实现电压可在12V—24V可调。

稳压电源的电路有许多种形式，即有分立元件组成又有集成稳压器加上一些外围元件组成，即有固定式的，又有可调式的。本设计按指标要求选用具有成本低、性能指标高、可靠、使用简单、安装调试方便等优点的集成稳压器LM317组成的稳压电源电路。

关键词：直流 稳压 变压 LM317

目 录

第1章 设计任务与要求 ········································································································· 1

第2章 方案与论证 ················································································································ 1

2.1 稳压电源组成 ··············································································································· 1

2.2 整流电路 ······················································································································ 2

2.3 滤波电路 ······················································································································ 2

2.4 稳压电路 ······················································································································ 2

2.5 保护电路 ······················································································································ 3

第3章 单元电路设计与参数计算 ··························································································· 3

3.1 电源变压器 ·················································································································· 3

3.2 整流电路 ······················································································································ 3

3.3 选择集成三端稳压器 ···································································································· 4

3.4 选择电源变压器 ··········································································································· 5

3.5 选用整流二极管滤波电容 ····························································································· 5

3.6 滤波电容 ······················································································································ 5

3.7 保护二极管选择 ··········································································································· 6

3.8 R1、R2的选择 ············································································································· 6

第4章 仿真与调试 ················································································································ 6

第5章 结论与心得 ················································································································ 7

参考文献 ································································································································· 8

1 第1章 设计任务与要求

采用LM317三端集成稳压器设计一稳压电源，其性能指标如下：

(1)输入交流电压220V/50HZ，输出电压VUDO24~12,最大输出电流mAI800max；

(2)电网电压波动±10%，输出电压相对变化量2%。稳压系数05.0Sr；

(3)内阻1.00r；

(4)工作温度25-44℃；

(5)有过流保护电路，当负载电流超过1.5IL时过流保护电路工作。

第2章 方案与论证

直流集成稳压电源设计思路：

(1)供电电压交流220V(有效值)50Hz，要获得低压直流输出，首先必须采用电源变压器将电压降低获得所需要交流电压；

(2)降压后的交流电压通过整流电路变成单向直流，但其幅度变化大(即脉动大)；

(3)脉动大的直流电压经过滤波电路变成平滑，脉动小的直流电；

(4)滤波后的直流电压，再通过稳压电路稳压，便可得到基本不受外界影响的稳定直流电压输出。

2.1 稳压电源组成

稳压电源由电源变压器、整流电路、滤波电路和稳压电路组成。稳压电源组成如图2-1所示。

+ 电 源 + 整 流 + 滤 波 + 稳 压 +

u1 u2 u3 uI U0

_ 变压器 _ 电 路 _ 电 路 _ 电 路 _

图2-1 稳压电源图

2 稳压电源整流与稳压过程如图2-2所示。

U1 U2 U3 U4

0 t 0 t 0 t 0 t

图2-2 稳压过程图

2.2 整流电路

(1)单相桥式整流电路

使用的整流器件较全波整流时多一倍，整流电压脉动与全波整流相同，每个器件所承受的反向电压为电源电压峰值，变压器利用率较全波整流电路高。电路如图2-3所示。

图2-3 稳压过程图

2.3 滤波电路

电容滤波电路的输出电压在负载变化时波动较大，它的负载能力比较差，只是用于负载较轻且变化不大的场合。电路图如图2-4所示。

2.4 稳压电路

因为设计要求可调式直流稳压器，所以应用可调式稳压芯片设计电路。

3 2.5 保护电路

采用二极管防止电路短路，损坏原件。

图2-４ 稳压过程图

第3章 单元电路设计与参数计算

3.1 电源变压器

电源变压器是将交流220V的电压变为所需要的电压值，并送给整流电路，变压器的变比由变压器的副边电压确定。

3.2 整流电路

整流电路常采用二极管的单相全波整流电路。在2U的正半周内，二极管1D、2D导通，3D、4D截止；在2U的负半周内，二极管3D、4D导通，1D、2D截止。正负半周内部都有电流流过的负载，且方向是一致的。电路的输出波形如图3-1所示。

图3-1 原理电路图

4 在桥式整流电路中，每个二极管都只在半个周期内导电，所以流过每个二极管的平均电流等于输出电流的平均值的一半，即：

15.0ofII (3-1)

电路中的每只二极管承受的最大反向电压为22U(2U是变压器副边电压有效值)。 在设计中，常利用电容器两端的电压不能突变和流过电感器的电流不能突变的特点，将电容器和负载电容并联或电容器与负载电阻串联，以达到使输出波形基本平滑的目的。选择电容滤波电路后，直流输出电压为：

21)2.1~1.1(UUo (3-2)

直流输出电流为：

)2~5.1(21IIo (3-3)

(I2是变压器副边电流的有效值)，稳压电路可选集成三端稳压器电路。

总体原理电路如图3-2所示。

图3-2 总体原理图

3.3 选择集成三端稳压器

因为要求输出电压可调，所以选择三端可调式集成稳压器。我选用LW317。LM317其特性参数：

输出电压可调范围：1.2V～37V；