UCC28070 Implement Bridgeless PFC Pre …

1 1 BridgelessPFCA pplicationReportSLUA517 JULY2009 UCC28070 ImplementBridgelessPowerFactorCorrection (PFC)Pre-RegulatorDesignLiuXueChao, (PFC) (CCM) , ,theEnergyEfficiencyAlliance's(NEEA's)80 PLUS initiative(andmoreoveritsBronze,Silveran dGoldderivatives) (ZVT)PFCorInterleavedPFC,forexample, ,bridgelessPFCattractsmoreinterestforit' L lineishigh, ,Q2andD2operateasBoostswitchingmodewhent heterminal N lineishigh, ,thelossesduetothebridgerectifierareelim inated, , ,forexample, , , , ,thereisnobridgerectifierloss, , JULY2009 UCC28070 ImplementBridgelessPowerFactorCorrection (PFC)Pre-RegulatorDesign1 SubmitDocumentationFeedbackAC LineLoD1D2Q1Q2 CoRoLNOperating Cellwhen L is highOperating Cellwhen N is highAC LineLoD1D2Q1Q2 CoRoLNAC (PFC)Pre-RegulatorDesignSLUA517 ,therearesomeobstaclesthatneedtoovercome .

2 BecausethelineisfloatingcomparedtothePFC stageground, ForcaonventionalPFC, ,forabridgelessPFC, ,whichmakesthebridgelessPFC scurrentsensingcomplicatedanddifficultto monitor. , , ' ,theswitchingnodeMOSFETQ2anddiodeD2aredi rectlyconnectedtoinputlineterminal, JULY2009 UCC28070 ImplementBridgelessPowerFactorCorrection (PFC)Pre-RegulatorDesign3 SubmitDocumentationFeedback2 SimplifiedSemi-BridgelessPFCAC , , ,directapplicationoftheswitchingnodehigh dv/dttotheinputterminalsisremovedandthus , ,twodiodes(DaandDb)linkthePFCoutputgroun dtotheinputline,andDaandDbofferthereturn path, , , (DcandDe)topeakchargethecommonPFCboostca pacitorCOduringtheinitialstartup, ,afterthecapacitorhasbeenpeakcharged,and theconverterisoperating, , , (PFC)

3 Pre-RegulatorDesignSLUA517 JULY2009 SubmitDocumentationFeedbackAC LineL1D1D2Q1Q2 CoRoL2 DaDbLNAC , ,thecurrentreturnsnotonlythroughDaorDb, ,when L lineishighwithinputvoltagesinusoidpositi ve(thesameresultswhen N lineishighwithinputvoltagesinusoidnegati ve),unfortunately, (a)MOSFETQ1 TurnsOffandD1isConducted(b)MOSFETQ1 TurnsOnandD1isReversedCurrentPathwhen L ,soitcanberegardedastwodiodes(Dbandbodyd iodeofQ2) , sbodydiodeconductionhaslittleimpactoneff iciencyStep1, JULY2009 UCC28070 ImplementBridgelessPowerFactorCorrection (PFC)Pre-RegulatorDesign5 SubmitDocumentationFeedbackAC LineL1D1D2Q1Q2 CoRoL2 DaDbLNVsRs3 WhyUsetheUCC28070?WhyUsetheUCC28070? ,suchasusingfourcurrenttransformerstomon itorcurrentofMOSEFTQ1andQ2andoutputtocap acitorwithload; , (PFC)devicethatintegratestwopulse-widthm odulationsoperating180 (CCM)PFC, , , ,currentsensingisacriticalissueforbridge lessPFC.

4 , UCC28070 ,duringtheon-timeoftheGDAorGDBoutputs, ,thecontinuousmonitoringoftheinputandout putvoltageviatheVINACandVSENSE pinspermitstheUCC28070tointernallyrecrea tetheinductorcurrentdown-slopeduringeach output' (RSYN),basedontheequationbelow, (PFC)Pre-RegulatorDesignSLUA517 JULY2009 SubmitDocumentationFeedbackAC LineL1D1D2Q1Q2 CoRoL2 DaDbLN123456789 CDRRDMVAOVSENSEVINACIMORSYNTHCSBCSAPKLIM TDMAXRTSSGDBGNDVCCGDAVREFCAOACAOBUCC2807 012V to 20 VCSACSBGDBGDAGDBGDACSACSBRARBCCDRRRDMRIM ORSYNRZVCZVCPVRDMAXRRTCSSRSRST1T2 RPK1 RPK2 RZCRZCCZCCZCCPCCPCCREFW aveform atCSx JULY2009 UCC28070 ImplementBridgelessPowerFactorCorrection (PFC)Pre-RegulatorDesign7 SubmitDocumentationFeedbackCTBRSYNS(10 N L k )R (k )=R W(1)WhyUsetheUCC28070?

5 LB=NominalZero-BiasBoostInductance( H) RS=SenseResistor( ) NCT=CurrentSenseTransformerturnsratio KR=RB/(RA+RB)= , ,volt-secondbalancingisveryimportanttoav oiditssaturation; , ,UCC28070createsuniquemultiplierarchitec turetoquantizeVRMS feed-forward(QVFF)circuitry, universal linerangeof86V~ ,UCC28070cansimplifythedesignofbridgeles sPFCbecauseofthefollowingbenefits: Currentsynthesizersimplifiesthecurrentse nsingcircuitwithoutaddinganyadditionalco mponents,thusaverageCCMbridgelessPFCcanb eachievedusingsimplecontrolmethod. ,wecansettherequireddithermagnitudeanddi therratetoreducetheEMInoise,whichisalsoc riticalforbridgelessPFC. (PFC)Pre-RegulatorDesign8 SLUA517 85 2D0 69V390-== (2)2002 6850 9 OUTIN _ RMSIN _ MINPWI.

6 AV V .h=== (3).W .. AV .OUTIN_MINP2 0 32002 0 3!IL1 1V85 0 9 == h(4)kIN_MINPLLV2 D85V 2 370 !HIL A 200 HZ D (5)2 OUTL1_RMS L2_RMSIN_MIN2V2 sin( ) VV2 sin( )IN_MINOUT IN_MINL1 5AV120 q-q p ==+ = hp (SLUU312) ,outputvoltageis390 VDC, ,thedesignercanrefertotheTI300-WInterlea vedApplicationReport(SLUA479)Step6,howev er,thedesignercanalloweachinductortohave moreinductorripplecurrentthanabridgeless PFCthanisdescribedinthatpaper, ,thereisnoripplecancellationratioK(D) , , (6)FortheothercalculationsregardingtheMO SFET sanddiodes, , ,theefficiencyimprovementofabridgelessPF Cisapproximatelybetween1%and2% ,110 VACand265 VAC, JULY2009 UCC28070 ImplementBridgelessPowerFactorCorrection (PFC)

7 Pre-RegulatorDesign9 SubmitDocumentationFeedback5 ConclusionEfficiency vs Output power (W)E f f ic ien c yConvertional PFCB ridgeless PFCE fficiency vs Output power (W)E ff ic ie n c yConvertional PFCB ridgeless (PFC)Pre-RegulatorDesignSLUA517 JULY2009 UCC28070 ImplementBridgelessPowerFactorCorrection (PFC) ,RonBrown,MacroSoldano,BridgelessPFCI mplementationusingonecyclecontroltechniq ue, ,Dong,W.,Zhao,Q.,FredLee,Performanceeval uationofCoolMOSTMandSiCdiodeforsingle-ph asepowerfactorcorrectionapplications, ,HighPowerFactorRectifierwithreducedcond uctionandcommutationlosses,Intelec, , sGuide-SLUU3212008, , (PFC)Pre-RegulatorDesignSLUA517 JULY2009 SubmitDocumentationFeedbackIMPORTANTNOTI CET exasInstrumentsIncorporatedanditssubsidi aries(TI)reservetherighttomakecorrection s,modifications,enhancements,improvement s, , , ,eitherexpressorimplied,isgrantedunderan yTIpatentright,copyright,maskworkright,o rotherTIintellectualpropertyrightrelatin gtoanycombination,machine, , ,conditions,limitations, (suchaslifesupport)

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