直流稳压电源之串联型晶体管稳压电路课件讲解

直流稳压电源之串联型晶体管稳压电路DCRegulatedPowerSupply——TheSeries-connectedTransistorVoltageRegulatorCircuit稳压电路VoltageRegulatorCircuit1、电路结构1并联型稳压电路CircuitstructureParallel-connectedvoltageregulatorcircuit学习目标LearningObjectives了解串联反馈式晶体管稳压电路的稳压原理了解稳压电源的主要技术指标Understandthevoltagestabilizationprincipleofseries-connectedfeedbacktransistorvoltageregulatorcircuits.Understandthemaintechnicalspecificationsofvoltageregulatorpowersupplies.串联型稳压电源Series-connectedVoltageRegulator1.稳压电源的主要指标（1）电压调整率SU（2）电流调整率SI（3）输出电压的温度系数ST1.KeyParametersofVoltageRegulators(1)VoltageregulationrateSU(2)CurrentregulationrateSI(3)Temperaturecoefficientofoutputvoltage1.电路一般结构

GeneralCircuitStructure串联式稳压电路由取样、基准电压、放大和调整四个环节组成。AUBTUREFUFR1取样R2UoRL调整

基准电压比较放大∞－＋Ui－＋取样环节：R1R2分压提取与输出Uo成正比的取样电压UFSamplingStage:ExtractingthesamplingvoltageUFproportionaltotheoutputvoltageUothroughR1

andR2voltagedivision.Theseries-connectedvoltageregulatorcircuitconsistsoffourstages:sampling,referencevoltage,amplification,andadjustmentadjustmentcomparisonandamplificationreferencevoltagesampling串联反馈型晶体管稳压电路SeriesFeedbackTransistorVoltageRegulatorCircuit串联型稳压电源Series-connectedVoltageRegulator2.稳压原理VoltageStabilizationPrinciple稳压过程按电网波动和负载电阻改变两种情况分述如下：Thevoltagestabilizationprocessisexplainedseparatelyfortwosituations:fluctuationsinthepowergridandchangesintheloadresistance.当电网波动Whenthepowergridfluctuates

Ui↑→Uo↑→UF↑→UBE↓→UCE↑→Uo↓；当负载电阻Whentheloadresistancechanges

RL↓→Uo↓→UF↓→UBE↑→UCE↓→Uo↑。电路为电压串联负反馈，调整管T连接成射极跟随器，

因而可得：Thecircuitemploysvoltage-seriesnegativefeedback.TransistorTisconnectedasanemitterfollower.

Therefore,itcanbederived:↑→↑AUBTUREFUFR1取样R2UoRL调整

基准电压比较放大∞－＋Ui－＋adjustmentcomparisonandamplificationreferencevoltagesampling串联型稳压电源Series-connectedVoltageRegulator或or

在深度负反馈条件下，|1+AuFu|>>1时，可得当反馈越深时，调整作用越强，输出电压Uo也越稳定AUBTUREFUFR1取样R2UoRL调整

基准电压比较放大∞－＋Ui－＋UCEUBEadjustmentComparisonandamplificationreferencevoltagesamplingUnderconditionsofdeepnegativefeedback,where|1+AuFu|>>1,wecanderive:Asthefeedbackbecomesdeeper,theadjustingeffectbecomesstronger,andtheoutputvoltageUobecomesmorestable.实际的串联式稳压电路ActualSeries-typeVoltageRegulatorCircuit1.稳压过程UoUFUCE2Uo当Ui增加或输出电流减小（RL增大）使Uo升高时IB2IC2UBE1UCE1R3T1T2UZRRW1RW2R1RWR2RLUO+_+_UiUFIB2IC2UBE1UCE2UCE1UBE2=（UF－UZ）VoltagestabilizationprocessWhenUiincreasesortheoutputcurrentdecreases(RLincreases),causingUotoriseR3T1T2UZRRW1RW2R1RWR2RLUO+_+_UiUFIB2IC2UBE1UCE2UCE1当Ui减小或输出电流增加（RL减小）使Uo降低时UCE2UoIC2UBE1UCE1UoUFIB2UBE2=（UF－UZ）WhenUidecreasesortheoutputcurrentincreases(RLdecreases),causingUotodecreaseR3T1T2UZRRW1RW2R1RWR2RLUO+_+_UiUFIB2IC2UBE1UCE2UCE12.RW的调压作用UCE2UoUBE1UCE1RW下调UFUBE2UZ不变UCE2UoUBE1UCE1RW上调UFUBE2UZ不变RegulationeffectofofRWRWdecreasedUZunchangedUZunchangedRWincreased实际的串联式稳压电路ActualSeries-typeVoltageRegulatorCircuitR3T1T2UZRRW1RW2R1RWR2RLUO+_+_UiUFIB2IC2UBE1UCE2UCE1KVL:UZ+UBE2=UF分压公式：Voltagedivisionformula:实际的串联式稳压电路ActualSeries-typeVoltageRegulatorCircuit3.输出电压的调节范围Adjustmentrangeoftheoutputvoltage例电路如图所示。

Example:Giventhecircuitasshowninthediagram.已知UZ=6V，R1=

R2=RP，试估算稳压电路输出电压Uo的调节范围。KnownUZ=6V，R1=

R2=RP,trytoestimatetheadjustmentrangeoftheoutputvoltageUoofthevoltageregulatorcircuit.解：由“虚短”，知道UF=UREF=UZ=6V，可估算出：Solution:Duetothe"virtualshort,"weknowU