显示器课程08版13、品牌机课外阅读高压板

ZVZCS- :AiCBAiCBDMode3:在QB開始導通時，反流器之輸出電壓Mode4:當變壓器在㆒次側電流I降到零值時，VAB被拑制為零值，此時與輸入電壓源Vi相比，其會有往負值方向增加的變動傾向。阻隔電容器其值非常小之阻隔電容器Cb兩端的電壓，則施Cb㆖的電壓完全施加在Lik及變壓器的㆒次側㆖，加在漏電感Lik㆖。阻隔電容器Cb可視為定電壓使㆒次側的電流I繼續保持為零值。在此期間Cb的源，變壓器㆒次側電流I呈線性㆘降而達到零值。電壓保持定值，QD仍然為導通的狀態，但是沒Mode6在QC導通後，因為高電壓施加到漏電感Lik㆖，使變壓器㆒次側電流I呈線性增加。至此則完成㆒個MeansurementofprimaryObject:PrimarysidewaveformofOZ960,MosFETandTransformertestAmbienttemperature:24°CScope:TektronixTDS360,S/N:A1003Currentprobe:TektronixP6022,S/N:B1006Powersupply:GWGPC-3030D,S/N:A1011Thermaltester:OPTEXPT-3S,S/N:A1010TestOZ960outputMosFEToutputTransformerPrimarysidevoltageandcurrentTestInFigA,TheswitchesofMosFETA,B,CandDareconfiguredsuchthatMosFETAandB,CandDareturnedoncomplementarily.ThedurationofAandD,BandCturnonsimultaneouslydeterminesanamountofenergyputintothetransformer.WhenBandDshiftleftsimultaneously,thedutycycle eshort.InFigB.ThethirdwaveformisamathematicalwaveformfromV_AB-V_CDwhichV_ABisDrainofMosFETA,BandV_CDisDrainofMosFETC,D.ItequalVcaddtransformerprimaryvoltageas andfifthwaveform.FigCisshowthetimmingofOZ960outputwaveformandprimarysideofFigFigFigOZ960function CapacitorforCCFLignitionThiscapacitorremainsresetatnochargeiflampisconnectedandatnormal OutputvoltagesenseItensuresthatoutputgetssufficientstrikingvoltagewhileoperatingthepower

Open-lampprotectionintheignitionperiodisprovidedthroughbothOVPandCTIMRtoensurearatevoltageisachievedandarequiredtimingissatisfied.RemovaloftheCCFLduringnormaloperationwilltriggerthecurrentamplifieroutputandshutsofftheinverter.ThisisalatchC8iscontrolstrikingtime.Strickingtime[second]=Whenoutputisopen,thevoltageofOVPisoverthan2VthentheCTIMERstarttoaccountstrikingTheOVPthreshedissetat2V.OutputvoltageissetbyC6andC14.TheVoiscalculated C Vo V 1Vo'2Diodedropvoltag 2.Vooo C6C14VooC C6C142. 6 1.t: 2.t: 3.t:VoutVin Vout VoutVinV2Vm VCVm VVeT/ ifRCVLVoutVMVVoutVamaxVD2VV'V 2V'2V

Vout 2VVout2VC1Hpp Enableinput;TTLsignalisR15andC9recifierthenoisefromON/OFF.WhenVENA>1.5V,theICwillbeturn Thesoft-starttimeisnotrelatedtothestrikingtimefortheCCFL.Itsimplyprovidesarateofriseforthepulsewidthwherediagonalswitchesareturnedon.Normally,a0.47uFcapacitoris VoltagesourcefortheR16andC11isrecifiercircuit,itsupplystablevoltageforOZ960 ogsignalground Referencevoltageoutput;2.5Vtypical CCFLcurrentfeedbacksignal CompensationoutputofthecurrenterrorTheCCFLcurrentisregulatedthroughthiserroramplifier.Thenon-invertingreferenceis1.25V

Thefeedbackloopisdetermineoutputcurrent.Theoutputcurrentiscalculated21.25V 2Ilamp(rms

0.45

lamp(rmsIfthereisadiodeontheFeedbackloop.Theoutputcurrentiscalculated1.25VVaVm1 R21V 1.250.45IrmsR21I

1.250.45 Low-frequencysignalforburst-modedimmingcontrol Triangularwaveforburst-modedimmingcontrolOZ960integratesaburst-modedimmingfunctiontoperformawidedimmingcontrolfortheCCFL.TheburstmodefrequencyissetbyC17,f[Hz]C17[nFTheramppeakofburstmodetriangleis3Vandrampvalleyis1V.WecanadjustVdimtocontrolLdutycycle. Powerground Resistorforprogrammingignitionfrequency Timingresistorsetoperationfrequency OperatingAresistorRTandacapacitorCTdeterminetheoperatingfrequencyofOZ960.Thefrequencyiscalculatedas:R21andC18determinetheoperationfrequency.Thefrequencyiscalcuated70fH[kHz]C[pF]R OZ960alsoprovideanoptionalstrikingfrequencyasStrikingWhenR22isused,itisconnectedinparallelwithR21duringtheignitionperiod.Thefrequencyiscalcuatedas:70fS[kHz]

18[pF]RS

RSR21//Becauseoperationfrequencyisknownnumber,C18andR21are70104RThanR22[k] whichfSf[kHz]C[pF]R[k]70 NDR_B:NMOSFETdriveoutputNDR_D:NMOSFETdriveoutputPDR_A:PMOSFETdriveoutputPDR_C:PMOSFETdriveoutput 1 1 L 23456789

P-mosfet'P-mosfet' D3,C15,R19isalevel-shiftcircuit,becauseOZ960’supplyvoltageis+5V,theoutputofPDRis5V,butthePMOSisswitchedbyVin(>5V),sothePDRmustbeshifted.HowtoselectionthevalueofRandC?TheRCshouldbelargemorethanT.IfRC>>T,thewaveformwillbeIfRCisnotlargeenough,thewaveformwillbeCisRandCareZenerdiodeisZenerdiodeis cementby

Ifinputvoltagerangeisfrom9V~21V,wecanassumemaxdutyis83%.Andmax.DutycyclehappenatinputvoltageInputvoltagethroughHBridge,WegetinputvoltagewaveformoftransformerasaboveWealsoassumeoutputvoltageoflampis550VWecangetR.M.Svalue.82820.4182820.41(8)21IfweusetransformerwhichTOKOBLX103B,secondaryoftransformerisVoN2550

N17.24*1500/N1Theequationisnotreallyexact;Actuallytoleranceisaboutcalculatetransformermagneticcurrentandcoreloss.

15%.Soitneedtofinetune,becausewecanSimulation ysisofOZ960FunctionalEnableLevelshiftcircuitfordrivetheP-MOSFET’sStrikingtimeandOVPcontrolFeedbackFunctional

IfVin=12VThenVA=5.6VVDDA=VA–VBESpec.PspiceEnable

R8andC8rectifierthenoisefromON/OFF,whenENA>1.5VtheICwillbeturnon.C8chargefrom0to1.5Vneed0.6ms,itisdelaytimefromON/OFFtoSoft-startNormally,a0.47uFcapacitorisLevelshiftcircuitfordrivetheP-MOSFET’sPSpiceStrikingtimeandOVPcontrolStrikingtimeOOV' VOOC4VO'VOVPVDVC6C4V C4CV12p18n2.8 12 pPspiceCVBC1

VOVPVC1C2 2V

1CC2VOVP2VD1C FeedbackPspice

Vout R2 2 R2 2IR2rmsVFB0.45f[kHz] 700000HC7[pF] 220StrikingRSR9//R11f[kHz] C[pF]R 220 Burst-modetivedi4gfL[Hz]

C12[nF 1.IfR2isknown,RR2VDDVDimHVDimLR adjH adjLR R2 2.IfR4isknown,2 V V V RVadjHVDimL2 V V V R R2 Lampcurrent=3.5mA~8.0mA�duty-cycle=�VDIM=52.152.1 50.90.9 IfR2=270KMeasurementandVerificationofOZ960MeasurementofwaveformofOZ960FunctionalWaveformofOZ960pinLandVadjvs.StrikingvoltageatopenOVPloopVin,Duty-cycleandlampvoltageOZ960signalwaveformofENA,CTIMR,OVP,SST,FBandCMPatopenlampstatewhenVadj=3.4V. NormallyOZ960signalwaveformofENA,CTIMR,OVP,SST,FBandVin=12V, Vin=19V, NormallyOZ960signalwaveformofENA,CTIMR,OVP,SST,FBandCMPVin=12V,Vadj=3.4V. Vin=19V,Vadj=3.4V. WaveformofOZ960pin andLpinofFBpinLpinofVadjvs.Strikingvoltageatopenlamp 2. 2. 2. 2.Strikingvoltagewaveformfix1. 2.3. 4.OVPloop ChangeC6from33nFto22nF➔ V C5 2V 22p220.5C 5

22 ChangeC5from22pFto33pF➔ V C5 2V 33p220.5 C 5

ChangeC5from22pFto27pF➔C5=27pF,VC6C5 2V33n27p220.5C 5

27 ChangeC5from22pFto18pF➔C5=18pF,V

C5 2V

33n18

220.5C 5

18 Vin,Duty-cycleandlampvoltageVinFrequencyDutyVlamp(kVp-Vlamp9FunctionaltestofOZ960inverterInverter:IV10101/TScope:TektronixTDS220,S/N:A1004Powersupply:GWGPC-3030D,S/N:A1011LCRmeter:Zentech100LCRMETERMulti-meter:HP34401A,S/N:A1001Thermaltester:OPTEXPT-3S,S/N:A1010TestVdimvs.Vccvs.Operationfrequencyvs.Burstfrequencyvs.RelationshipbetweenVlampandFBTestVdimvs.Vccvs.9 9*t1:Vlampexceptriseandfall 9*t1:Vlampexceptriseandfall Operationfrequencyvs.fH-*Thereisanunstableoutputcurrent,whenfrequencyatBurstfrequencyvs.fBurst fBurst) RelationshipbetweenVlampandFB =150Hz,T=6.67ms),Vp-9 Vp- Vp- Vin=12V,Vp- TransformerturnInputvoltagerangeis9Vto21V,weassumemax.dutycycleis84%.Andmax.dutycyclehappenatinputvoltage8V.Theoutputvoltageoflampis450Vrms.WecangettheR.M.S.821821IfthesecondaryturnsoftransformerisVoN2450 N1ActuallytoleranceisaboutActuallyIftheinputvoltageislowerthan8.9Vinvertercan’tturnWheninverterisnormallyworkthenstartdecreaseinputvoltage,itwillshut-downwhileinputvoltageis8.4Vandthedutycycleis80%.O2:ching(ZVS)O2:-ZVSiscontrolledbyO2chip.(quitestable).iscontrolledbytransformer.VeryOutputwaveformisalmostsineandsymmetryisveryTI1451:Waveformismostlikelyastriangle.tocontrol)ncy(NoteasytoO2:DesignercaneasytodecidetheoptimizedoperationfrequencyforTI1451:Operatingfrequencyisdecidedbyoscillatedoftransformer,andtheequivalentloadfromth