Altium Designer PCB仿真教程.docx

Altium Designer PCB仿真教程.docx

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AltiumDesignerPCB仿真教程

SPICEModelCreationfromUserData

Summary

ThisapplicationnoteprovidesdetailedinformationoncreatingandautomaticallylinkingaSPICEsimulationmodeltoaschematiccomponent,basedondataenteredintoAltiumDesigner'sSPICEModelWizard.

InordertosimulateacircuitdesignusingAltiumDesigner'sMixed-SignalCircuitSimulator,allcomponentsinthecircuitneedtobesimulation-ready–thatis,theyeachneedtohavealinkedsimulationmodel.

Thetypeofmodelandhowitisobtainedwilllargelydependonthecomponentand,tosomeextent,onthepersonalpreferenceofthedesigner.Manydevicemanufacturer'ssupplysimulationmodelscorrespondingtothedevicestheymanufacture.Typically,it'sassimpleasdownloadingtherequiredmodelfile（SPICE,PSpice®）andhookingituptotheschematiccomponent.

SomeofthemorebasicanalogdevicemodelsinSPICErequirenodistinctmodelfile–onlyspecificationofsimpleparametervalueswhendefiningthemodellink（e.g.Resistor,Capacitor）.Attachingthesetypesofmodelstoacomponentisstraigthforwardandsimplyaprocessofselect-and-enter（selectthemodeltypeandentertheparametervaluesdirectlyinanassociateddialog）.

Somemodelsmayneedtobewrittenfromscratch–forexampleusingthehierarchicalsub-circuitsyntaxtocreatetherequiredsub-circuitmodelfile（*.ckt）.Others–ifthedeviceisdigitalinnature–willrequirethedevicetobemodeledusingtheproprietaryDigitalSimCode™language,thedefinitionofwhichislinkedtothroughanintermediarymodelfile.

Certainanalogdevicemodelsbuilt-intoSPICEprovideforanassociatedmodelfile（*.mdl）inwhichtoparametericallydefineadvancedbehavioralcharacteristics（e.g.SemiconductorResistor,Diode,BJT）.Creationofthismodelfilebyhandandthenlinkingitmanuallytotherequiredschematiccomponentcanbequitelaborious.Notanymore–enterAltiumDesigner'sSPICEModelWizard.UsingtheWizardthecharacetristicsofsuchadevicecanbedefinedbasedonuser-acquireddata.Theparameters–enteredeitherdirectlyorextractedfromsupplieddata–areautomaticallywrittentoamodelfileandthatfilelinkedtothenominatedschematiccomponent.

Formoreinformationonlinkingamodelfile,refertotheLinkingaSimulationModeltoaSchematicComponentapplicationnote.

Fordetailedinformationondefiningadigitalsimulationmodel,refertotheCreatingandLinkingaDigitalSimCodeModelapplicationnote.

TheSPICEModelWizard

TheSPICEModelWizardprovidesaconvenient,semi-automatedsolutiontocreatingandlinkingaSPICEsimulationmodelforarangeofanalogdevices–devicesthatarebuilt-intoSPICE,andthatrequirealinkedmodelfile（*.mdl）.ThebehavioralcharacteristicsofthemodelaredefinedbasedoninformationyousupplytotheWizard.Theextentofthisinformationdependsonthedevicetypeyouwishtocreateamodelfor–rangingfromthesimpleentryofmodelparameters,totheentryofdevicedataobtainedfromamanufacturer'sdatasheetorbymeasurementsgainedfromthephysicaldeviceitself.

ThefollowingsectionsdiscusstheuseoftheWizard–fromaccesstoverification.

AccessingtheWizard

ThewayinwhichyouaccesstheWizarddependschieflyonhowyouwanttoaddtherequiredSPICEmodel.Amodelcanbeadded:

∙Toanewlycreatedcomponent（createdbytheWizard）inaschematiclibrarydocument

∙Toanexistingcomponentinaschematiclibrarydocument

∙Toaplacedcomponentonaschematicdocument.

AccessintheSchematicLibraryEditor

Ifyouareunsureofthedeviceyouwishtomodel,accesstheWizardbychoosingTools»XSpiceModelWizardfromthemainmenus.ByaccessingtheWizardinthisway,youwillbeabletochoose:

∙Whichparticulardeviceyouwishtomodel,fromthelistofsupporteddevicetypes（seeSupportedDeviceTypes）.

∙Whethertoaddthesubsequently-generatedSPICEmodeltoanexistingcomponentinthelibrarydocumentortoanewcomponentthatiscreatedbytheWizardandaddedtothatdocument.

TheSPICEModelWizardisessentiallyacollectionofwizards-oneperdevicemodelsupported.ThisismadeespeciallyevidentwhenaccessingtheWizardfromtheSimModeldialog.

∙Ifyouwishtoaddthemodeltoanexistingcomponent,andhavelaunchedtheWizardusingthemainmenucommand,ensurethatthatcomponentistheactivecomponentinthelibrary.

YoucanalsoaccesstheWizardwhilesettingupasimulationmodellinkforanexistingcomponent.FromtheSimModeldialog,simplyensurethatthechosenentryintheModelSub-KindfieldisoneofthedevicetypessupportedbytheWizard（seeSupportedDeviceTypes）,thenclickontheCreatebutton–totherightoftheModelNamefield（Figure2）.

Figure2.AccesstheWizarddirectlyfromtheSimModeldialog.

TheSimModeldialogitselfcanbeaccessedfromaschematiclibrarydocumentinoneofthefollowingways:

∙FromtheLibraryComponentPropertiesdialog（Tools»ComponentProperties）,byaddingasimulationmodelintheModelsregionofthedialog.（Appliestotheactivecomponentonly）.

Ifyouareeditinganexistinglinkedsimulationmodel,usingtheWizardwillreplacetheexistingmodelwiththenewlycreatedone.

∙FromtheSCHLibrarypanel,byaddingasimulationmodelintheModelssectionofthepanel.（Appliestotheactivecomponentonly）.

∙FromtheSchematicLibraryEditor'smaindesignwindow,byaddingasimulationmodelintheModelsregionofthewindow.（Appliestotheactivecomponentonly）.

∙FromtheModelManagerdialog（Tools»ModelManager）,byaddingasimulationmodelintheModelsregionofthedialog.（Appliestotheselectedcomponent（s））.

AccessintheSchematicEditor

UsingtheWizardwillreplaceanyexistingmodelwiththenewlycreatedone.

TheWizardcanalsobeaccessedwhendefiningthesimulationmodellinkforaplacedcomponentonaschematicsheet.Again,accessismadefromtheSimModeldialogbyclickingtheCreatebutton–providedofcoursethatthemodeltypeisoneofthoseforwhichadedicatedWizardisavailable.

Figure3.AccessingtheWizardforaplacedschematiccomponent.

SupportedDeviceTypes

TheWizardcanbeusedtocreateSPICEmodelsforthefollowinganalogdevicetypes:

∙Diode

∙SemiconductorCapacitor

∙SemiconductorResistor

∙Current-ControlledSwitch

∙Voltage-ControlledSwitch

∙BipolarJunctionTransistor（BJT）

∙LossyTransmissionLine

∙UniformDistributedRCTransmissionLine

NamingtheModel

WhenusingtheWizardtoaddamodeltoanewlibrarycomponent,thenamespecifiedforthemodelwillbeusedtonamethecomponentalso.

OneofthemostimportantstepsasyoufollowthepagesoftheWizard,istoprovideanameforthemodelyouarecreating.Infact,youwillnotbeabletoproceedtotheparameterdefinitionstageoftheWizarduntilyouhaveenteredaname.

Aftercreation,thisnamewillappearintheModelNamefieldoftheSimModeldialog.Themodelfileitselfisalsocreatedusingthisname（ModelName.mdl）.

Figure4.Defineameaningfulnameforthemodel.

Whennamingthemodel,youalsohavetheoptiontoenterashortdescriptionforit.Thiscouldbethefunctionofthemodel（e.g.SemiconductorResistor）,oramorespecificreferencetoavalueorconfiguration（e.g.NPNBJT）.

CharacteristicstobeModeled

Aftergivingthemodelaname,youwillproceedtooneormorepagesdealingwiththecharacteristicstobemodeled.ThemodeltypessupportedbytheWizardcanbecategorizedintothefollowingtwogroups:

∙Thosemodelsrequiringdirectentryofvaluesforvariousmodelparameters.Forfurtherinformation,seethesectionDeviceModelsCreatedbyDirectParameterEntry.

Aparameterspecifiedinthemodelfileforadevicewilloverrideitsdefaultvalue（inherenttotheSPICEengine）.

∙Thosemodelsrequiringtheentryofdatafromwhichtoextracttheparametersthatdefinethechosendevicecharacteristics.Thedataenteredisobtainedeitherbydirectmeasurementresultsfromthephysicaldevice,orfromamanufacturer'sdatasheet.Forfurtherinformation,seethesectionDeviceModelsCreatedbyParameterExtractionfromData.

OnlyparametersdefinablewithinamodelfileareconsideredbytheWizard.AnyparametersthataredefinableatthecomponentlevelforadeviceshouldbeaddressedusingtheParameterstaboftheSimModeldialog,oncetheWizardhasfinishedcreatingthemodelfile.

GeneratingtheModel

Afterentryoftherequireddata/parameters,theWizardwilldisplaythegeneratedmodel（Figure5）.ThisisthecontentthatwillbesavedtotheMDLfile.

Figure5.Previewingthegeneratedmodelfilecontent.

Editingofthemodelcanbecarriedoutdirectlyonthispage,givingyoutheutmostcontrolovermodelspecification.

Onceyouaresatisfiedwiththemodeldefinition,simplyclickNexttopasstotheendoftheWizard.ClickingFinishwillallowyoutosavethemodel.UsetheSaveSPICEModelFiledialogtodeterminewheretheresultingMDLfileshouldbesaved.Bydefault,thefilewillbesavedtothesamedirectoryastheschematiclibrarydocument.Youcanalsochangethenameofthefileatthisstage,shouldyouwish.

Ifyouhaverequestedthemodelbeattachedtoanewcomponent,thatcomponentwillbecreatedandaddedtothelibrarydocument.

Althoughthemodelislinkedautomaticallytothecomponent–neworexisting–youshouldmakeahabitofverifyingthemappingofschematiccomponentpinstopinsofthemodel.SimplyaccesstheSimModeldialogfortheattachedmodel,clickonthePortMaptab,andcheckthepinmapping–makinganychangesifrequired.

Figure6.Verifythecomponent-to-modelmapping.

Defineanyadditionalparametersavailableforthemodel–ontheParameterstaboftheSimModel