电路原理课件讲义英文版-Chapter-5

IfAissuccessinlife,thenAequalsXplusYplusZ.WorkisX,YisplayandZiskeepingyourmouthshut.---AlbertEinsteinChapter5OperationalAmplifiers5.1Introduction5.2OperationalAmplifiers5.3IdealOpAmp5.4InvertingAmplifier5.5NoninvertingAmplifier5.6SummingAmplifier5.7DifferenceAmplifier5.8CascadedOpAmpCircuits5.1IntroductionOperationalAmplifier(OpAmp运算放大器):1.activecircuitelement(有源电路元件)2.electronicunitthatbehaveslikeavoltage-controlledvoltagesource3.alsovoltageorcurrent-controlledcurrentsourceFunction:mathematicaloperations(数学运算)(sum加,amplify乘,integrate积分,differentiate微分)Advantages:versatile,inexpensive,easytouse,funtoworkwithUsages:inverter逆变器,voltagefollower电压跟随器,summer加法器,differenceamplifier差分放大器5.2OperationalAmplifiersOpAmp1.anactivecircuitelement有源电路元件designedtoperformmathematicaloperationsofaddition加,subtraction减,multiplication乘,division除,differentiation微分,andintegration积分.2.anelectronicdevice电子设备consistingofacomplexarrangementofresistors,transistors,capacitors,anddiodes二极管.3.acircuitbuildingblock电路组件availableinintegratedcircuitpackages集成电路块inseveralforms.Typicalopamppackage:(a)pinconfiguration指针配置(b)circuitsymbol电路符号72346InvertinginputNoninvertinginputOutputVV15OffsetNullBalanceInvertinginputNoninvertinginputNoconnectionOutputBalanceVV21345678Poweredopamp:23647ccVccVii0i1i2i012iiiiiEquivalentcircuitmodel:dAvdviR0R1v2v0v21dvvv021()dvAvAvvWhereA:open-loopvoltagegain开环电压增益Ri:inputresistanceR0:outputresistanceTypicalrangesforopampparameters:ParameterTypicalrangeIdealvaluesOpen-loopgain,A105to108Inputresistance,Ri106to1013Outputresistance,R010to100Supplyvoltage,Vcc5to24V0Feedback:1.Anegativefeedbackisachievedwhentheoutputisfedbacktotheinvertingterminaloftheopamp.2.Closed-loopgain:theratiooftheoutputvoltagetotheinputvoltageswhenthereisafeedbackpathfromoutputtoinput3.OpamparegenerallyusedincircuitswithfeedbackpathsThreemodesofopampoperationregion:1.Positivesaturation正饱和,v0=Vcc2.Linearregion,-Vcc≤v0=Avd≤Vcc3.Negativesaturation负饱和,v0=-VccccVccV0PositivesaturationNegativesaturation0vdvExample150210,2,50iARMR10vsv10k20ki0741sv0vi011vdAv20k10k050R2iRMdvTheequivalentcircuitFindtheclosed-loopgainv0/vs;Determinecurrentiwhenvs=2VSolution:sv0vi011vdAv20k10k050R2iRMdvAtnode1:110133310102000102010svvvvv10200301100svvv1023sorvvv0123svvvAtnode0:1003201050dvvvAvButvd=-v1,andA=2×105,Then1001400(200,000)vvvv01.9999699svvAssignment1.Readsection5.1and5.2inpages166-1682.TranslateEnhancingyourcareerinpage165Vocabularymeasurement测量paramount极为重要的proliferate激增ammeter安培表voltmeter电压表ohmmeter欧姆表oscilloscope示波器spectrumanalysis谱分析仪signalgenerator信号发生器patent申请专利specialist专家5.3IdealOpAmpIdealOpAmp(理想运算放大器)1.Infiniteopen-loopgain,A≌∞.2.Infiniteinputresistance,Ri≌∞.3.Zerooutputresistance,R0≌0.dv10i20i0v1v21vvTwoimportantcharacteristics1.i1=0,i2=02.vd=v2-v1≌0orv1=v2.Example2AccordingtothecharacteristicsofIdealopamp:2v1v20i10i0i0v40k5ksv020kSolution:1svv20i200515409vvv21vvSo:019svv09svvAtnode0:00040520vvimA001,90.20.450.65sWhenvVvVSoimACalculatetheclosed-loopgainv0/vs.Findi0whenvs=1VKeepinmind1.Throughoutthisbook,weassumethateveryopampisideal.2.Throughoutthisbook,weassumethatopampoperatesinthelinearrange.5.4InvertingAmplifier10viv1RfR02v1v1i2i0A0VAtnode1:12ii1101ifvvvvRRButv1=v2=0foranidealopamp,hence,01ifvvRR01fiRorvvRVoltagegain:01fviRvAvR10viv1RfR02v1v1i2i0A0VEquivalentcircuitfortheinverter1fiRvR1R0viv01fiRvvRAninvertingamplifierreversesthepolarityoftheinputsignalwhileamplifyingitAssignmentSolvetheproblems5.7,5.10and5.17inpages191-1935.4NoninvertingAmplifierAtnode1:12ii10110fvvvRRButv1=v2=vi,hence,01iifvvvRR01(1)fiRorvvRVoltagegain:011fviRvAvR10viv1RfR02v1v1i2iVoltageFollower(UnityGainAmplifier):0()fRshortcircuit0ivviv1()orRopencircuit10viv1RfR02v1v1i2i01(1)fiRvvR0ivvMerits:Highinputimpedance高输入阻抗Function:IsolatetwocascadedstagesofacircuitUsage:Intermediate-stage(orbuffer)amplifierFirstStageSecondStage0vivVoltageFollower:Example3Calculatetheoutputvoltagev00vab6V4V10k4kSolution1:Usingsuperposition00102vvvWherev01:the6-Vvoltagesourcev02:the4-Vvoltagesource(1)Togetv01:thecircuitisaninverter01106154vV(2)Togetv02:thecircuitisannoninvertingamplifier0210(1)4144vV(3)Thus001021vvvV0vab6V4V10k4kSolution2:NodalanalysisButva=vb=4,andso01vVAtnodea:06410aavvv0464410v5.5SummingAmplifierAtnodea:123iiiiBut111avviR0123123()fffRRRvvvvRRR222avviR333avviR0afvviR0avAsummingamplifierisanopampcircuitthatcombinesseveralinputsandproducesanoutputthatistheweightedsumoftheinputsa0vfR02v1v1ii03v2i3i0i2R1R3R5.5DifferenceAmplifierAtnodea:220111(1)aRRorvvvRR1012aavvvvRR0v2R001R3R1v2vavbv4RAtnodeb:2340bbvvvRR4234bRorvvRRButabvv2420211341(1)RRRvvvRRRR21220211341(1)(1)RRRRorvvvRRRR21220211341(1)(1)RRRRvvvRRRR312021241,()RRRWhenthereisvvvRRR1234IfRRandRR021vvv(Subtractor减法器)Adifferenceamplifierisadevic