PSPICE計算機仿真(三)

PSPICE計算機仿真

SimulationProgramwithIntegratedCircuitEmphasis

CH7

THESTEPRESPONSEAND

SWITCHES

階躍響應

7.1Simplestepresponse

Example11

■a)Theswitchinthecircuitshownin

Fig.69isclosedatt=0.Attheinstant

theswitchisclosed,theinitialcurrent

inthe10mHinductoris90mA,andthe

voltageacrossthecapacitoris10V.

■Fig.69alsoshowsthereferencesfor

theseinitialconditions.Makea

preliminaryanalysisofthestep

response,andcalculatethemaximum

valueofVcandthetimeatwhichit

occurs.

■b)CreateaPSpiceschematic,perform

transientanalysis,andplotVcversust

from0to3000ps.

■c)ComparethePSpicesolutionwiththe

preliminaryanalysis.

4Solutiona)

■FromthesolutionofExample10,wealready

knowthattheresponseisunderdamped.

■Furthermore,weknowthatthedamped

periodis897.60ps,andthat

、

s1=-1OOO+j，7000

s

2-1000-j7000

■Thestep-responsesolutionforVctakesthe

form

/'.\-1000

乙=L+⑸cos7000%+B2sm7000t)e

■TheinitialvaluesofVcanddVc/dtarethe

sameasinExample10,andthefinalvalueis

21V.HenceB'l=-31VandB'2=2V,so

/.\—1000t

v=21-(31cos7000/-2sm7000t)e,t>0

■ThemaximumvalueofVcis41.22Vat

419.32|JS.

4Solutionb)

■InFig.71,weusedtwocursorsthis

time,andmovedthesecondcursorby

holdingdowntheShiftkeywhileusing

theleftandrightarrowkeys.The

cursorsallowyoutoreadthevaluesof

Vc(max)andTddirectlyfromthe

Probeplot.

4Solutionc)

■TheoutputofthePSpiceanalysisyields

v_(max)=41.361V

TJ=899.503us

V21V

7.2PiecewiseLinearSources

（分段線性電源）

■Example12illustratestheuseofthe

piecewiselinearsourceformodelingthe

switchingthattakesplaceinatransient

analysisproblem.

Example12

■ThecircuitshowninFig.72hasbeenin

operationforalongtime.Att=0,the

80Vsourcedropsinstantaneouslyto20

V.ConstructaPSpiceschematic,using

aPWLsource,tomodelthiscircuit.The

resultsoftheanalysisshouldbeaplot

ofVo(t)versust.

Solution

■DesignExplorer-[F:\PSpice\exams_protel\pspice_exams.Ddb],|g|x|

*'聲FileEditViewPlaceDesignToolsSimulatePLDReportsWindowHelp-|g|X|

.；—塌....V；-■；>,々總；..

怙百口昌QQ回itZ◎:>：+富瑞T>蒯盤I臆sc?

七1二款幽吉?QsE>-rXEl

tf\fig72_ex12,Sch

p$pice_exams.Ddb

RlR2

7.5k2k

/ATE口00&到麒

，工art|A旬⑥除口⑥&0⑨口I]a|F:\,.,|因OrG.,|麒SC,,,|厘]P5p.」展Clie：不單《蒯10:1^

■注意V2正負極

■V2屬性(Fig.75)

既OrCADCapture-[PropertyEditor],|g|x|

@FileEditViewPlaceMacroAccessoriesOptionsWindowHelp■俯1x|

gJMgId區(qū)圖畫I工klIVPWL3閡屎1-閾叫詞叼—劉良|Jj

匕|臼卜|母|J|||

New..1|Apply|Displ剪…|DeletePropertyFilterby:|<All>:Help

SourcePackageT1T10T2T3T4T5T6T7T8T9V1V10|V2V3V4V5.

1田SCHEMATICI：PAGE1:V2VPWL040e-6400e-3:°6060

1一…二......：??”?：：："..

<I生E卻$X_膽㈣遮N賽人P褥4I艇馳典一AG就唯入E亟]Lil______I

Ready

事如代||!Jj團您除2J卷⑨口」F4P5pi期led…|畫MicrosoftPow…“陽OrCADCaptur…蒯個（理414:09

S；OrCADIapture((SCHIMA1”1：PA(止I)],|g|x|

國FileEdit作wPlsc^MicroP5piceZAccessortesOptkrsWindov?H咖.|t?|x|

1|團引副x|甯|胡|三VPWL胤像|旬凰地薰春JRWU

包日

?I

迎回3Ml暮除巷0€)⑧口|]0F:爐Spic...|畫Microsof…|圖OrCADC…^Simulation5…個Q型”副

14:16

任SCHEMATlCl-trans-OrCADPSpiceA/ODenio|examIZ-S(IUMATJI：Itr<i,|g|x|

FileEditViewSimulationTracePlotToolsWindowHelp-|g|X|

圜▼|百令Q昌，為海|SCHEMATIC1-trans?II

觀氫物Q皿曲蜒自心J落即\?」8木卑#封用寺必厘汨想

V(out^)

______________________________________________________Time_______________________IProbeCursor

Al=40.000a,33.698

g|examl2-SCH...

A2=80.000%22.489

dif=-40.000m,11.209

XJ1Biaspointcalculated/

TransientAnalysis

TransientAnalysisfinished

Simulalioncomplete

evices

ForHelp,pressFlTime=.4100%nmniimniMM

,Start|

用國0除口巷|2?電口|，_JF八P5pic,.,|畫Microsof…|圖OrCADC…腰5cHEMA…副件4理14:08

Results

■TheProbeplotinFig.76,whichuses

thecursorstodeterminetheoutput

voltageatt=40msandt=80ms,yields

thefollowingresults:

tVo（t）

064

4033.698（書上:33.654）

8022.489（書上:22.498）

■Furthermore,youcanseefromthe

ProbeplotthatVo(t)叩proaches16V

astapproachesoo.

7.3RealisticSwitches

（實際開關）

■Weillustratetheuseofthenormally-

openedswitchinExample13to

examinetheeffectofnonzeroswitch

resistanceonthestepresponseofthe

RLCcircuit.

Example13

■UsePSpicetomodelthecircuitshown

inFig.69,withsomemodifications.

■Assumethatthevoltagesourceisthe

sameasthatusedinExample10,anduse

thesamevaluesinspecifyingtransients

analysis,

■Butassumethattheresistanceofthe

switchintheONpositionis10Q

■ThengenerateaplotofVcversust.

Comparetheresultsherewiththosein

Example10.

KSiOrCADCapture-[/-(SCHEMATIC1:PAGE1)]-|g|x|

國FileEditViewPlaceMacroPSpiceAccessoriesOptionsWindowHelp-Ifllx|

1|團引副圣圄包三三||swtClose3胤像Ia閽|回間叼圃目三］

七|臼＞|字|網(wǎng)區(qū)|網(wǎng)

igstart]Jj國⑥聯(lián)2J卷00⑧口I，圖Or…g]P5…|魚金…||

個4型通副15:06

Components

■EVAL/Sw_tClose

既OrCADCapture-[PropertyEditor]-|g|x|

@FileEditViewPlaceMacroAccessoriesOptionsWindowHelp-Ifllx|

glMgid/陶原1a』（swjg皿刁限除除|閾叫川|由|疑廛|用量J|

匕I臼>|母|J|||

New…|Npply|Display…|DeleteProperty|Filterby:|<All>▼]Help

|RCLOSED|Reference|ROPEN|SourceLibrary|SourcePackage|TCLOSE|TTRAN|Value.

>

o?

1田SCHEMATIC!:PAGE1:U310心PROGRAMFSw^tC/osei"SwtClose

一!.

I?|\PartsXSchematicNetsXPins/TitleBlocks/Globals/PortsI，

1.一<、*-———----r-一-.，>■J■..一，、——J>>.-.-.—，i±r

Ready

jgStartjN用回舂聯(lián)口特侮心⑧口|]J：\-|||S|0r-期四…|金金…|eWi,..|

個《理酬酬15:06

[J.￡SCHEMATICl-trans-OrCADPSpiceA/DDemo-[examl3-SCHEMATICl-trans(active)]-|g|x|

FileEditViewSimulationTracePlotToolsWindowHelp-|g|X|

圜▼SCHEMATICI-trans

曳戛密3皿曲蜒自1H多那,、,?J木譚#?用寺必哎汨更

40V

超

曷

ZOV

OV

1.5*2.SB