TI电容隔离技术详解

CapacitiveIsolation

ATechnicalOverview

TemperatureTheRealWorldPressurePositionSpeedFlowHumiditySoundLightISOLATIONPLCmCDSPDIGITALINTELLIGENCEADCTRANSCEIVERSRS-485/CANSignalIsolationWhatisIsolation?Galvanicisolation:

AlthoughCircuit1andCircuit2exchangesignals,

nocurrent(electrons)passfromCircuit1toCircuit2.Whyisisolationrequiredinelectricalsystems:BreakgroundloopsReducecommonmodenoiseSafetyfromhighvoltagesCircuit1Circuit2SignalsVoltagesupply1Voltagesupply2Ground1Ground2WhyIsolation?

GroundLoopsMorethanoneconductivepathbetweentwocircuitscreatesaground-loopMultiplegroundpathsmayleadtounintendedequalizationcurrentsGroundloopcanbebrokenbyDisconnectingthegroundsCommon-modechokesFrequencyselectivegroundingDifferentialamplifiersGalvanicisolatorsOnlygalvanicisolationprovidesprotectionforverylargepotentialdifferencesWhyIsolation?

CommonModeNoiseSignalsreferenced

toGND1Signalsreferenced

toGND2Basic/FunctionalIsolation

vs.ReinforcedIsolation“Animprovedbasicinsulationwithsuchmechanicalandelectricalpropertiesthat,initself,theinsulationprovidesthesamedegreeofprotectionagainstelectricalshockasdoubleinsulation.Itmayconsistofoneormorelayersofinsulationmaterial.”[UL-60950-1]Basic/FunctionalIsolation

vs.ReinforcedIsolation(cont’d)WhenisReinforcedrequired:6kVppsystems(e.g.600VIGBTs/FETs)Today:allMedicalapplications(5kVrms!)Future:MedicalapplicationsforisolationfromthepatientNote:thisisnotcompleteandsubjecttochange.Exceptionsmayapply!ApplicationsutilizingIsolationPrimaryTask:IsolationbetweenHigh-PowerandControlSignalsIsolationofBus-NodestopreventCorruption

ofthecompleteBus&CommonModeRejectionIndustrial:

RoboticsPLCinput/outputisolationIndustrialnetworksMotorcontrolPowersuppliesApplicationsutilizingIsolationCommunications:PBX(PrivateBranchExchange)andcentralofficeTelephoneterminalequipmentTelephoneswitchingequipmentModemsISDNEthernet/PoEMedical:MicrowavetherapyPatientmonitoringElectrocardiographsDefibrillatorsPrimaryTask:Medical:IsolationbetweenPowerandPatientCommunications:IsolationbetweenPowerandCallerIsolationofBus-Nodestoprevent

CorruptionofthecompleteBusConsumerElectronics:Video(TV,VCR,etc.)PlasmadisplaysElectronicgamingHomeappliancesApplicationsutilizingIsolationComputers&OfficeEquipmentIsolatedI/OPrintersandplottersFaxmachinesPrimaryTask:IsolationbetweenHigh-PowerandUserNomenclatures/Definitions(1/3)OperationVoltage:VoltagethatmaybeappliedcontinuouslyacrosstheIsolationbarrier,mostly560Vpkor890VpkTransientVoltage:Voltagethatmayoccurtemporarilyacrossthebarrier(testedperVDEfor1minute),mostly4kVpk(relatesto3kVrmsperUL,astestedfor10sonly)or6kVpkSurgeVoltageSingleeventsurge,withtheassumptionthatalleffectshavebeenrecoveredfrompriortoanothersurge-event,mostlyratedfora10kVsinglepeak.Nomenclatures/Definitions(2/3)Basic/FunctionalIsolation:Assumesasinglelevelofisolationwithacertainstrength.ApplicableformostapplicationsinindustrialforfieldbussesandAC-equipmentupto400Vrms,andforconsumerelectronics.Mostlyratedat560Vpkcontinuous,4kVpktransientvoltage.Reinforced/DoubleIsolation:DoubleIsolationassumesatwo-levelisolationwithacertainstrengtheach.Reinforcedaddressesasinglelevelofisolationthat,however,providesthesamereliabilityasthetwo-layer.

ApplicableformostmedicalapplicationsandAC-equipmentabove400Vrms.Mostlyratedat890Vpkcontinuous,6kVpktransient,10kVsurgevoltage.Medicalneeds5kVrmstransient.

IntrinsicallysafeApplicationsdemanddoubleisolation.Note:theEnd-equipment-standard(e.g.IEC-60950forcommunicationsorIEC-60601-1formedical)dictateswhatisneededonsiliconlevelNomenclatures/Definitions(3/3)CommonModeTransientSuppression:DiscussesthequickchangeinReferencepotentialprimarytosecondary.It’sgivenasthedU/dtuptowhichnofalsetoggelingoftheoutputwilloccur(e.g.35kV/us).Usuallyscales~linearlywithVcc.CreepageandClearanceDiscussesthesurface-distancethatmayconductifwet/polluted,respectivelytheair-distance.For560V/4kVmostly4mmissufficient,for890V/6kVmostly8mmisneeded.Dependsonpollutiondegree5Questions……toalloweducatedsolution-proposalsIsolationstrength:

basic/reinforced?Isolationvoltage:

4kVpeak,560Vpeakcontinuos/

6kVpeak,890Vpeakcontinous?Stand-aloneisolationorintegration(Transceiver,Gate-Driver,Data-Converter)?SupplyVoltages?Channel-count?NewGenerationCapacitiveIsolationHighvoltagecapacitorIsolatorconstructionTopplate=CuBottomPlate=SiliconSubstrate(doped)InterLevelDielectricMoldcompoundBondwireMin8mmHighVoltageCapacitorConstructionPackage/designationCreepagemmClearancemmNarrowbodySOIC/D4.84.3Gullwing/DUB6.86.1WidebodySOIC/DW8.18.3Creepagedistance:Shortestdistancebetweentwoconductiveinputtooutputleadsmeasuredalongsurfaceofinsulation.Clearancedistance:Shortestdistancebetweentwoconductiveinputtooutputleadsmeasuredthroughair(lineofsight).Note:Package-changedand

nowallows8.3mmmin!ActualDie-PictureIt’sallcapacitiveAllisolatedcouplerscanbemodeledasI/Oandcapacitivecoupled(activeorparasitic)Capa-citiveISO72XInductiveADuM1xxxGMRIL7xxOpticalHCPL-07xxCIO1pF1pF1.1pF0.6pFe,materialSiO2=4.5

Polyimide=2.8Polyimide=2.8Moldcomp.

e=3.6CapacitiveOpticalGMRInductiveSource:TIAppnoteSLLA198/iso721TimingparametersMed.Perf.OptoHighPerf.OptoMagneticCapacitiveSignalingRateMbps’s50Mbps150Mbps200MbpsPropagation

DelayTime100ns20ns32ns12nsPulseWidth

Distortion35ns2ns2ns1.5nsCh-Ch-skew40ns16ns2ns1.6nsPart-Part-Skew40ns20ns10ns2nsCompetitiveComparison

Reliability(1/2)Med.Perf.OptoHighPerf.OptoMagneticCapacitiveESDonallPinsNospecNospec/±2kVNospec/±2kV±4kVCMTransientImmunity5kV/us20kV/us25kV/us25kV/usTemperature-40..85oC-40.125oC-40.125oC-55.125oCCompetitiveComparison

Reliability(2/2)60%confidence90%confidenceTech-nologyAmbientTemp.MTTF[years]FITMTTF[years]FITCapa-citive125oC56392122555055oC4395200.31758080.7Magnetic125oC33583417466555oC2608250.441356060.84Optical125oC20572781439150oC290394115990Samplesize/failures:ISO721:45447/0;ADuM1201:35411/1;HCPL-0721:160/0CompetitiveComparison

MagneticImmunityIEC61000-4-81KHzFieldFrequency106xhigherImmunitythanADUM1100Source:TIAppnoteSLLA181A/iso721(Clickonabovelinkforwebinfo)E-fieldimmunityTestReportE-fieldimmunityTestReportMagneticISO7221C1Mbps:ComparisonofRadiatedNoiseSpectrum–AntennaHorizontalMagnetic:1Mbpsoperation@5VVccISO7221:1Mbpsoperation@5VVccEN55022ClassBRadiationsTesting25Mbps:ComparisonofRadiatedNoiseSpectrum–AntennaHorizontalMagnetic:25Mbpsoperation@5VVccISO7221:25Mbpsoperation@5VVccEN55022ClassBRadiationsTestingCompetitiveComparison

HighVoltageLifetimeSource:TIAppnoteSLLA197/iso721Lifeexpectancy:ISO72x>>CompetitionISO72xADUM1100CompetitiveComparison

HighVoltageLifetime

UsingwidelyacceptedE-ModelmethodologyADUM1100ISO72xISO72x:Lifeexpectancyis28yearsat560Vpeakor400VrmsCompetition:Lifeexpectancy<10years240partssince12/15/05@1000Vrms0failsafter>30khIccComparisonFigureofMerritt:

BandwidthperSupplyCurrentCompetitiveComparison

PowerUp/DownISO721ADUM1100Powerupbehavior:Vcc2powersupplyisonInputstateisLCh1isOutput:TransitionfromfailsafeHtoLCh2isVcc1beingturnedon,typicalturnontimeisinmillisec.Powerdownbehavior:Vcc2powersupplyisonInputstateisLCh1isOutput:TransitionfromLtofailsafeHCh2isVcc1beingturnedoff,typicalturnofftimeisinmillisec.TIMakesIsolatorsEasytoUse/iso721

GetStartedTodayEvaluationmodulesSamplesApplicationssupportIBISmodelsDatasheetsTechnicaldocumentationApplicationnoteson:High-VoltageLifetimeMagneticFieldImmunityISO72xFamilyofDigitalIsolatorsComplementsTI’sindustrialproductportfolio:interface,dataconverter,DSP,MCU,amplifier,power&logicIsolatedProducts–Stand-AloneSinglesTriplesQuadsDualsISO7240A/C/MISO7241A/C/MISO7242A/C/MISO7230A/C/MISO7231A/C/MISO7220A/B/C/MISO7221A/B/C/MISO721/MISO722/MTriplesQuadsDualsISO7440MISO7441MISO7430MISO7431MISO7420MISO7421MISO7640MISO7641MISO7630MISO7631MISO7620MISO7621M560Vpk(cont’)4kVpk(transient)890Vpk+(cont’)6kVpk(transient)10kV(surge,tbc)AvailabletodayLow-Power-versions,pin-compatiblewithISO72xx560Vpk(cont’);4kVpk(transient)(ClickonProductformoreinformation)IsolatedProducts–Integrated2ndorderD-SModulator(4kV)AMC120310MHzISO1176,ISO308x,

ISO1x,ISO3xIsolatedTransceiversRS-485(ClickonProductformoreinformation)2ndorderD-SModulator(6kV)AMC120420MHzIsolatedRS-485TransceiverwithIntegrated

TransformerDriverISO1177RTM:1Q10Samples:1Q10IsolatedCANTransceiverISO1050PreviewCross-ReferencetoADISeeESPunder“productfamilypresentations”intheisolationproduct-folders:Continued…(alsoinspeakernotes)SingleChannelSignalIsolators:

ISO72x4000VpeakIsolation560VpeakcontinuousSignalingRateOptions

(ISO721B:5Mbps,ISO721:100Mbps,ISO721M:150Mbps)UL1577,IEC60747-5-2(VDE0884,Rev.2),

IEC61010-1andCSAApproved3.3V/5VOperation(anycombination)25kV/µsTransientImmunityand

HighElectromagneticImmunityFailsafeOutputandHighImpedanceatInputandOutputwithLowVccMulti-ChannelStand-aloneIsolators:Dualsxdesignatesspeedoption:A=1Mbps;B=5Mbps;C=25Mbps;M=150MbpsMulti-ChannelStand-aloneIsolators:Triplesxxxdesignatesspeedoption:A=1Mbps;C=25Mbps;M=150MbpsAllinDWpackagexxMulti-ChannelStand-aloneIsolators:Quad-channelxdesignatesspeedoption:A=1Mbps;C=25Mbps;M=150MbpsAllinDWpackagexxxIsolated485TransceiversISO308x,ISO1x,ISO3x“StandardRS-485”3.3Vand5Vhalf-duplexandfull-duplex

(‘176and‘180configuration)1Mbps

and

25MbpsnoIDODEoutputISO1176:IsolatedRS/485ProfiBus5Vhalf-duplex25MbpsoptimizedforProfibus-ApplicationsISODEavailableIsolatedCANTransceiverISO10505VCANtransceiverISO11898compliant3.3V/5VisolatedlogicinterfaceHighEMImmunity15kV/ustransientimmunityBusfaultprotectionof-27Vto40VDominanttimeoutfunctionThermalShutdownprotectionHighInputimpedancewithlowVcc1Mbps

ISO–485withTransformerDriver

SimpleCompleteSolution-ISO1177/ISO37/ISO3088Features1Mbps/20Mbps/40Mbps1/8Unitload–256nodesonabusGlitch-FreeFailsafe(Open,Shorted,Idle)SiliconIntegratedSiO2

Insulator4kVpk/2500VrmsIsolation,

560Vworking/operatingUL1577,

IEC60747-5-2(VDE0884,rev.2),IEC61010-1&CSApendingEVM–ISO1177EVM/

ISO37EVM/ISO3088EVMISO1177–ProfiBus-DecISO37–3VRS485–Q1ISO3087–5VRS485–Q13V-5VVcc1DA2303/2304-AL(Coilcraft)Low-CostIsolatedPowerSupplyFeaturesLow-Cos