《低频功率放大器课件.ppt》由会员分享，可在线阅读，更多相关《低频功率放大器课件.ppt（46页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、6.1 基本放大电路基本放大电路6.2 共发极放大电路的结构、特点、用途。共发极放大电路的结构、特点、用途。6.3 共集电极放大共集电极放大(射极输出器射极输出器)电路电路 的结构、特点、用的结构、特点、用 途。途。6.4 差分放大电路。差分放大电路。6.5 互补对称功率放大电路。互补对称功率放大电路。第六项第六项 低频功率放大低频功率放大LOGO1.理解这两种最基本放大电路的结构、特点。理解这两种最基本放大电路的结构、特点。2.了解差分的工作原理及作用。了解差分的工作原理及作用。3.了解互补对称功率放大工作原理及性能特点。了解互补对称功率放大工作原理及性能特点。本项基本要求本项基本要求LOG
2、O6.1基本放大电路基本放大电路 放大的基本概念放大的基本概念放大是将微弱变化信号放大成较大的信号放大是将微弱变化信号放大成较大的信号实质是通过输入微小的信号能量去控制晶实质是通过输入微小的信号能量去控制晶体三极电流的作用。体三极电流的作用。即通过放大电路将直流能量转换成交流电即通过放大电路将直流能量转换成交流电能量输出。能量输出。放大电路的基要：放大电路的基要：1.要有要有 足够大的放大倍数足够大的放大倍数(电流、电压、功率电流、电压、功率)。2.要求放大信号波形实真尽量小。要求放大信号波形实真尽量小。3.要求工作稳定。要求工作稳定。基本放大基本放大电路路类型型 v1、共发射极放大电路 v
3、电路组成如图6-1（a）所示v2、共集电极放大电路v 电路组成如图6-1（b）所示v3、共基极放大电路 v 电路组成如图6-1（c）所示 v v（a）共发射极放大电路 （b）共集电极放大电路 （c）共基极放大电路v图6-1基本放大电路类型2.静态工作点 如图6-2所示 ui=0时，电路的IB、IC、UBE、UCE值静态工作点 记作：IBQ、ICQ、UBEQ、UCEQ 其中：UBEQ=0.60.8V 硅管0.10.3V 锗管IBQ=VBB-UBEQ/RbICQ=IBUCEQ=VCC-ICCRCICQUCEQIBQ VCCRbVBBcbeRCUBE 图6-2所示静态工作点示意图 (IBQ,UBEQ
4、)和和(ICQ,UCEQ)分别对应于输入输出特性曲线上分别对应于输入输出特性曲线上的一个点称为静态工作点。如图的一个点称为静态工作点。如图6-3所示所示iBuBEIBQUBEQQiCuCEICQUCEQQ图6-3 静态工作点3.3.设置静态工作点的必要性设置静态工作点的必要性 既然放大的放大的对象是象是动态信号，信号，为什么在什么在输入信号入信号为零零时要要求晶体管求晶体管有合适的直流有合适的直流电流和流和电压？（1）交直流并存：）交直流并存：uBE=UBEQ+ui，iB=IBQ+ib （2）设置合适）设置合适Q点，交流驮载到直流上，保证点，交流驮载到直流上，保证ui在整个在整个周期内，周期内
5、，T 工作在放大状态，工作在放大状态，uo不失真。不失真。静态时输入短路静态时输入短路UBEQ=0、IBQ=0，输出电压必然失真！，输出电压必然失真！图6-4静态工作点示意图第二章 基本放大电路 第二章 基本放大电路 动态信号驮载动态信号驮载在静态之上在静态之上输出和输入反相！输出和输入反相！只有设置合适静只有设置合适静Q点，使交流驮载在直流之点，使交流驮载在直流之上，保证在信号的整个周期内晶体管始终上，保证在信号的整个周期内晶体管始终工作在放大区，工作在放大区，uO波形才能不失真！波形才能不失真！波形分析波形分析 2.2 2.2 基本共射放大电路基本共射放大电路第二章 基本放大电路 阻容耦合
6、放大电路阻容耦合放大电路各点波形和静态工作点各点波形和静态工作点Rb+VCCRcC1C2uitiBtiCtuCtuotuiiCuCuoiBIBQ=(VCC-UBEQ)/RbICQ=IBQUCEQ=VCC-ICQRc第二章 基本放大电路 4.5.1 共集电极放大电路共集电极放大电路2.2.静态分析静态分析1.共集电极电路结构如图示共集电极电路结构如图示该电路也称为该电路也称为射极输出器射极输出器由由得得直流通路直流通路 6.3共集电极放大电路共集电极放大电路电压增益电压增益输出回路：输出回路：输入回路：输入回路：电压增益：电压增益：其中其中一般一般，则电压增益接近于，则电压增益接近于1 1，电压
7、跟随器电压跟随器即即。3、在共集在共集电极极电路特点路特点在共集电极电路中，输入信号是由三极管的基极与集电极两端输入的,再在交流通路里看，输出信号由三极管的集电极与发射极两端获得。因为对交流信号而言，（即交流通路里）集电极是共同接地端，所以称为共集电极电路。共集电极电路具有以下特性：（1）输入信号与输出信号同相；（2）无电压放大作用，电压增益小于1且接近于1，因此共集电极电路又有“电压跟随器”之称；（3）电流增益高，输入回路中的电流iB输出回路中的电流iE和iC；（4）有功率放大作用；（5）适用于作功率放大和阻抗匹配电路。元器件元器件电阻：容电二极管晶体三极管电位器元器件1.电阻电阻电阻的作用
8、：阻碍电流的流动。在电路中主要是分流分压的作用。2.电容电容电容作用：1.具有通交隔直。2.具有充电放电。3.具有储存能量。电解电容电解电容 普通电容普通电容3.晶体二极管晶体二极管发光二极管普通二极管普通二极管 晶体二管种类比较多：发光二极管、稳压二极晶体二管种类比较多：发光二极管、稳压二极管、整流二极管、光电二极管、变容二极管等。管、整流二极管、光电二极管、变容二极管等。晶体二极的特点：晶体二极的特点：具有单向导电性。具有单向导电性。正向电阻小，反向电阻大。正向电阻小，反向电阻大。4.晶体三极管晶体三极管Click to edit title style2.Describe content
9、s for a Chart Description of the companys sub contents Description of the companys sub contents1.Describe contents for a Chart Description of the companys sub contents Description of the companys sub contentsChart Title in here2003200420052006305070120Diagram-ThemeGallery is a Design Digital Content
10、&Contents mall developed by Guild Design Inc.-ThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.-ThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.Description of the companys sub contentsDescription of the companys sub contentsDes
11、cription of the companys sub contentsDiagramTextTextTextTextText4.Description of the business5.Description of the business1.Description of the business2.Description of the business3.Description of the businessThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.Click
12、to edit title styleContents01Contents02Contents03Contents04Contents05Contents060%20%40%60%80%100%18.5%17.5%8.7%23.6%63.6%84.3%ThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.DiagramDescription of the contentsDescription of the contentsDescription of the contentsT
13、hemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.200420052006 ContentsThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.Click to edit title style Title in here Title in hereDescription of the contentsText in hereText in hereDescri
14、ption of the contentsDescription of the contentsDescription of the contentsDescription of the contents1.Title2.Title3.Title4.Title*Description of the contents*Description of the contentsDiagram Content Title Description of the contents Description of the contents Content Title Content Title Descript
15、ion of the contents Description of the contents Description of the contents Description of the contents ContentsThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.Click to edit title styleClick to add TextClick to add TextClick to add TextClick to add TextClick to a
16、dd TextTitle in hereTitle in hereTitle in hereText in hereText in hereText in hereDescribe a vision of company or strategic contents.Describe a vision of company or strategic contents.Click to add TextClick to add TextClick to add TextClick to add TextClick to add TextClick to add TextClick to add T
17、extClick to add TextClick to add TextDiagramDescribe a vision of company or strategic contents.Describe a vision of company or strategic contents.Describe a vision of company or strategic contents.Describe a vision of company or strategic contents.Describe a vision of company or strategic contents.v
18、 ThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.Click to edit title styleContentsContentsContentsContentsThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.-Click to add Text-Click to add Text-Click to add Text-Click to add Text
19、ThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.-Click to add Text-Click to add Text-Click to add TextThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.Click to add TextDiagramStep 1Step 2Step 3Title in hereText inhereTitle in h
20、ereText inhereTitle in hereText inhere1.Describe contents for a Step1 -Description of the sub contents -Description of the sub contents2.Describe contents for a Step2 -Description of the sub contents -Description of the sub contents3.Describe contents for a Step3 -Description of the sub contents -De
21、scription of the sub contentsText in hereClick to edit title styleThemeGallery is a Design Digital Content&Contents mall developedby Guild Design Inc.ThemeGallery is a Design Digital Content&Contents mall developedby Guild Design Inc.ThemeGallery is a Design Digital Content&Contents mall developedby
22、 Guild Design Inc.A GroupC GroupB GroupClick to edit title styleLevel 1Level 2Level 3Level 4Level 5 Description of the contents Description of the contents Description of the contents Description of the contents Description of the contentsv ThemeGallery is a Design Digital Content&Contents mall deve
23、loped by Guild Design Inc.Click to edit title style2004TextTextText20052006Text in hereText in hereText in hereText in hereText in hereText in hereClick to edit title styleText in hereTitle in hereTitle in hereText in hereText in here2003200420052006 Description of the contents Description of the co
24、ntents Description of the contents Description of the contents Description of the contents Description of the contents Description of the contents Description of the contentsv ThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.Click to edit title styleThemeGallery i
25、s a Design Digital Content&Contents mall developed by Guild Design Inc.ContentsContentsContentsContentsDiagramDescribe a vision of company or strategic contents.Describe a vision of company or strategic contents.Describe a vision of company or strategic contents.Title in hereTitle in hereTitle in he
26、reTitle in hereTitle in hereTitle in hereThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.DiagramThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.A title about contentDescribe a vision of company or strategic contents.DiagramPle
27、ase write down of contents explanation for Business Area.Business AreaBusiness AreaBusiness AreaBusiness AreaPlease write down of contents explanation for Business Area.Please write down of contents explanation for Business Area.Please write down of contents explanation for Business Area.Please write down of contents explanation for Business Area.DiagramTitleTitleTitleDescription of the companys productsDescription of the companys technologyDescription of the companys contents ThemeGallery is a Design Digital Content&Contents mall developed by Guild Design Inc.LOGOAdd your company slogan