OB2279 DataSheet

©On-BrightElectronicsConfidential-1-OB_DOC_DS_79A0OB2279CurrentModePWMControllerFreqShufflingwithLatchShutdownGENERALDESCRIPTIONOB2279isahighlyintegratedcurrentmodePWMcontrolICoptimizedforhighperformance,lowstandbypowerandcosteffectiveofflineflybackconverterapplications.PWMswitchingfrequencyatnormaloperationisexternallyprogrammableandtrimmedtotightrange.Atnoloadorlightloadcondition,theICoperatesinextended‘burstmode’tominimizeswitchingloss.Lowerstandbypowerandhigherconversionefficiencyisthusachieved.VDDlowstartupcurrentandlowoperatingcurrentcontributetoareliablepoweronstartupdesignwithOB2279.Alargevalueresistorcouldthusbeusedinthestartupcircuitforreducedpowerloss.Theinternalslopecompensationimprovessystemlargesignalstabilityandreducesthepossiblesub-harmonicoscillationathighPWMdutycycleoutput.Leading-edgeblankingoncurrentsenseinputremovesthesignalglitchduetosnubbercircuitdiodereverserecoveryandgreatlyreducestheexternalcomponentcountandsystemcostinthedesign.OB2279offerscomprehensiveprotectioncoverageincludingCycle-by-Cyclecurrentlimiting(OCP),VDDUnderVoltageLockout(UVLO),VDDOverVoltageProtection(OVP),VDDClamp,GateClamp,OverLoadprotection(OLP)andOverTemperatureprotection(OTP),etc.DifferentlatchshutdownoptionsareofferedonOB2279indifferentdeviceversion.VversionhasOVPLatchshutdown.TversionsupportsbothOVPandOTPlatchshutdown.LversionprovidesallOVP,OTPandOLPlatchshutdowncontrol.ExcellentEMIperformanceisachievedwithOn-Brightproprietaryfrequencyshufflingtechniquetogetherwithsoftswitchingcontrolatthetotempolegatedriveoutput.Toneenergyatbelow20KHZisminimizedinoperation.Consequently,audionoiseiseliminatedduringoperation.OB2279isofferedinSOP-8andDIP-8packages.FEATURES■On-BrightProprietaryFrequencyShufflingTechnologyforImprovedEMIPerformance■PowerOnSoftStart■ExtendedBurstModeControlForImprovedEfficiencyandMinimumStandbyPowerDesign■AudioNoiseFreeOperation■ExternalProgrammablePWMSwitchingFrequency■InternalSynchronizedSlopeCompensation■LowVIN/VDDStartupCurrent(3uA)andLowOperatingCurrent(2.3mA)■LeadingEdgeBlankingonCurrentSenseInput■CompleteProtectionCoveragewithselectiveprotectionsforLatchShutdownoVDDOverVoltageProtection(OVP)–LatchShutdownoOverTemperatureProtection(OTP)–AutorecoveryorLatchShutdownoOverLoadProtection.(OLP)–AutorecoveryorLatchShutdownoVDDUnderVoltageLockoutwithHysteresis(UVLO)oGateOutputVoltageClamp(16.5V)oBuilt-inOCPCompensationtoAchieveMinimumOPPVariationoverUniversalACInputRange.APPLICATIONSOfflineAC/DCflybackconverterfor■Adaptor■NotebookAdaptor■LCDMonitor/TV/PC/Set-TopBoxPowerSupplies■Open-frameSMPS■PrinterPowerTYPICALAPPLICATIONOn-BrightConfidentialToHighray©On-BrightElectronicsConfidential-2-OB_DOC_DS_79A0OB2279CurrentModePWMControllerFreqShufflingwithLatchShutdownGENERALINFORMATIONPinConfigurationThepinmapofOB2279inDIP8andSOP8packageisshownasbelow.OrderingInformationPartNumberDescriptionOB2279AP-VDIP8,VversionwithOVPLatchOB2279AP-TDIP8,TversionwithOVP/OTPlatchOB2279AP-LDIP8,LversionwithOVP/OTP/OLPlatchOB2279CP-VSOP8,VversionwithOVPlatchOB2279CP-TSOP8,TversionwithOVP/OTPlatchOB2279CP-LSOP8,LversionwithOVP/OTP/OLPlatchNote:AllDevicesareofferedinPb-freePackageifnototherwisenoted.PackageDissipationRatingPackageRθJA(°C/W)DIP890SOP8150AbsoluteMaximumRatingsParameterValueVDDClampVoltage35VVDDClampContinuousCurrent10mAVFBInputVoltage-0.3to7VVSENSEInputVoltagetoSensePin-0.3to7VVRTInputVoltagetoRTPin-0.3to7VVRIInputVoltagetoRIPin-0.3to7VMin/MaxOperatingJunctionTemperatureTJ-20to150oCMin/MaxStorageTemperatureTstg-55to150oCLeadTemperature(Soldering,10secs)260oCNote:Stressesbeyondthoselistedunder“absolutemaximumratings”maycausepermanentdamagetothedevice.Thesearestressratingsonly,functionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunder“recommendedoperatingconditions”isnotimplied.Exposuretoabsolutemaximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.On-BrightConfidentialToHighray©On-BrightElectronicsConfidential-3-OB_DOC_DS_79A0OB2279CurrentModePWMControllerFreqShufflingwithLatchShutdownMarkingInformationTERMINALASSIGNMENTSPinNumPinNameI/ODescription1GNDPGround2FBIFeedbackinputpin.PWMdutycycleisdeterminedbyvoltagelevelintothispinandcurrent-sensesignallevelatPin6.3VINIConnectedthroughalargevalueresistortorectifiedlineinputforStartupandlinevoltagesensing.4RIIInternalOscillatorfrequencysettingpin.AresistorconnectedbetweenRIandGNDsetsthePWMfrequency.5RTIDualfunctionpin.EitherconnectedthroughaNTCresistortoGNDforovertemperatureshutdowncontrolorusedaslatchshutdowncontrolinput.6SENSEICurrentsenseinputpin.ConnectedtoMOSFETcurrentsensingresistornode.7VDDPDCpowersupplypin.8GATEOTotem-polegatedriveoutputforpowerMOSFET.On-BrightConfidentialToHighray©On-BrightElectronicsConfidential-4-OB_DOC_DS_79A0OB2279CurrentModePWMControllerFreqShufflingwithLatchShutdownBLOCKDIAGRAMRECOMMENDEDOPERATINGCONDITIONSymbolParameterMinMaxUnitVDDVDDSupplyVoltage11.525VRIRIResistorValue100133KohmTAOperatingAmbientTemperature-2085oCOn-BrightConfidentialToHighray©On-BrightElectronicsConfidential-5-OB_DOC_DS_79A0OB22