Efficiency-Optimized,Synchronous Flyback, High …

1 ReferenceDesignSLVA475 January2012 efficiency - optimized ,SynchronousFlyback, high -PowerPoEController/ConverterTheTPS2 3754is ,powered-device(PD) (SLVU301) istargetedat25-W, synchronous , (at25 C).. January2012 efficiency - optimized ,SynchronousFlyback, high -PowerPoEController/ConverterSubmitD ocumentationFeedbackCopyright 2012, (SLVU301) arenotedontheschematicshownin Newflybacktransformerdesign Betterselectionofmagnetizinginductancefo rCCMoperation Newwindingstrategytoreducecopperlosses Usessamecoreandbobbinsizeandfootprint RCDclampimprovements DiodeusedforfasterprimaryFETturnoff Newdead-timeresistorvalueforoptimumeffic iencyatfullloadandacceptableefficiencyat noload.

2 Useoffeedforwardresistorforbettercontrol ofpeakcurrentandvoltageathigherinputvolt age. Otherupdates:Compensation,improvedslopec ompensation,40-VsynchronizedFETforlowdra in-sourcestress. Otherbenefits LowerprimaryMOSFET peakdrain-sourcevoltageduringoverloads VoiceoverInternetProtocol IPtelephones WirelessLAN wirelessaccesspoints Security Efficient,generalmarketdesign Self-driven, synchronous ,rectifiedseconda ry 25-WoutputpowerfromPoweroverEthernet(PoE )orfroma 48-Vadapter 5-Voutputvoltage2 efficiency - optimized ,SynchronousFlyback, high -PowerPoESLVA475 January2012 Controller/ConverterSubmitDocumentationF eedbackCopyright 2012, (at25 C) 36-44mAInrushcurrent-limit100-180 Operatingcurrent-limit850-1100 Vin 57V,ILOAD (max)

3 Vin 57V5-Voutput--5 AOutputripplevoltage,Vin= 48V,ILOAD= 5 A5-Voutput-50-mVpeak-to-peakEfficiency,V inatJ289% efficiency ,VinatJ3 Vin= 48V,ILOAD= 5 A5-Voutput91% efficiency ,Converter92%Swit chingfrequency225-275kHz3 SLVA475 January2012 efficiency - optimized ,SynchronousFlyback, high -PowerPoEController/ConverterSubmitD ocumentationFeedbackCopyright 2012,TexasInstrumentsIncorporated++++ ,SynchronousFlyback, high -PowerPoESLVA475 January2012 Controller/ConverterSubmitDocumentationF eedbackCopyright 2012,TexasInstrumentsIncorporated9590858 0757065605550012345 efficiency - %I - Output Current - AOAdapter InputConverterPoE - Output Current - AOV - Output Voltage - throughFigure9 January2012 efficiency - optimized ,SynchronousFlyback, high -PowerPoEController/ConverterSubmitD ocumentationFeedbackCopyright 2012, (5V) ,SynchronousFlyback, high -PowerPoESLVA475 January2012 Controller/ConverterSubmitDocumentationF eedbackCopyright 2012, January2012 efficiency - optimized ,SynchronousFlyback, high -PowerPoEController/ConverterSubmitD ocumentationFeedbackCopyright 2012,TexasInstrumentsIncorporatedVQ1-D(S EC)VQ2-D(PRI) (Ch1)

4 Andprimary-sideFET(Ch2).Theoutputis loadedat5 (PoE).Theoutputwasloadedto0 NoOutputLoad8 efficiency - optimized ,SynchronousFlyback, high -PowerPoESLVA475 January2012 Controller/ConverterSubmitDocumentationF eedbackCopyright 2012, (PoE).Theoutputwasloadedto5 OutputFullyLoaded9 SLVA475 January2012 efficiency - optimized ,SynchronousFlyback, high -PowerPoEController/ConverterSubmitD ocumentationFeedbackCopyright 2012, (SLVU301) is ,SynchronousFlyback, high -PowerPoESLVA475 January2012 Controller/ConverterSubmitDocumentationF eedbackCopyright 2012, ,Ceramic,100V,X7R,10%0805 StdStd1C100330pFCapacitor,Ceramic,100V,X 7R,10%0603 StdStd2C10,C111uFCapacitor,Ceramic,1uF,1 00V,X7R,15%1210 StdStd1C1410nFCapacitor,Ceramic,100V,X7R ,10%0603 StdStd3C15,C16,47uFCapacitor,Ceramic,10V ,X5R,15%1210 StdStdC172C18,C19330uFCapacitor,Aluminum , ,20% ,Ceramic,100V,X7R,10%0805 StdStd1C201uFCapacitor,Ceramic,16V,X7R,1 5%0603 StdStd2C21, ,Ceramic,16V,X7R,10%0603 StdStd1C221200pFCapacitor,Ceramic,50V,X7 R,15%0603 StdStd1C231000pFCapacitor,Ceramic,100V,X 7R.

5 15%0603 StdStd1C242200pFCapacitor,Ceramic,2KV,X7 R,15% ,Ceramic,25V,X7R,10%0805 StdStd1C2622uFCapacitor,Aluminum,25V,20% , ,Ceramic,16V,X7R,15%0603 StdStd1C293300pFCapacitor,Ceramic,50V,X7 R,15%0603 StdStd4C3,C4,C5, ,Ceramic,100V,X7R,15%0603 StdStdC61C3027nFCapacitor,Ceramic,50V,X7 R,15% ,Ceramic,50V,X7R,15%0603 StdStd1C71000pFCapacitor,Ceramic,2kV,X7R ,15%1210 StdStd3C8,C12, ,Ceramic,100V,X7R,15%0805 StdStd1C947uFCapacitor,Aluminum,63V, 20% , ,Schottky,2-A,100-VSMBB2100-13 DiodesInc1D1001N4148W-7-FDiode,Signal,30 0-mA,75-V,350-mWSOD-1231N4148W-7-FDiodes 2D14,D18 SMAJ58 ADiode,TVS,58-V, ,UltraFastRectifier,1-A,200-VSMBMURS120T 3 OnSemi1D16 BAV20 WSDiode,SmallSignal,250mA,150 VSOD-323 BAV20 WSMicroCommercialComponents2D17,D19 BAV99 Diode,DualUltraFast,Series,200-mA,70-VSO T23 BAV99 Fairchild2D2,D3LN1371 GDiode,LED,Green,10-mA, ,LED,UltraBrightRed,10-mA, ,D6,D7,B1100 Diode,Schottky,1A,100 VSMAB1100 Diodes,IncD8,D9,D10,D11,D12,D134FB1,FB2, 500 Bead,Ferrite,2000mA,60m 1206MI1206L501R-10 StewardFB3,FB42J1,J25520252-4 Connector,Jack,Modular, , ,J11ED1514 TerminalBlock,2-pin,6-A, ,J10 PTC36 SAANH eader,Male3-pin,100milspacing,(36-pinstr ip)

6 3 PTC36 SAANS ullins5J5,J6,J7,J8,PTC36 SAANH eader,Male2-pin,100milspacing,(36-pinstr ip) ,SMT, ,80-m ,SMT, , "DR74-R33 Cooper1Q1 SiR422 DPMOSFET,NChan,40V,50A, PWRPAKS0-8 SiR422 DPVishay-Siliconix1Q2Si7898 DPorMOSFET,NChannel,150V, ,85-m PWRPAKS0-8orSi7898 DPorVishayorFDMS2572 POWER56 FDMS2572 Fairchild1Q3 MMBT3906 Bipolar,PNP,40V,200mA,225mWSOT23 MMBT3906LT1 OnSemi1R1100 KResistor,Chip,1/16W,1%0603 StdStd1R100121 KResistor,Chip,1/16W,1%0603 StdStd1R1239 KResistor,MetalFilm,1/4watt, 5% ,Chip,1/16W,1%0603 StdStd2R14, ,Chip,1/16W,1%0603 StdStd1R1610 Resistor,Chip,1/10W,1%0805 StdStd11 SLVA475 January2012 efficiency - optimized ,SynchronousFlyback.

7 high -PowerPoEController/ConverterSubmitD ocumentationFeedbackCopyright 2012, (continued) ,Chip,1/16W,1%0603 StdStd1R1810 Resistor,Chip,1/16W,5% ,Chip,1/10W,1%0805 StdStd1R215 KResistor,Chip,1/4W,1% ,Chip,1/16W,1%0603 StdStd1R21332 Resistor,Chip,1/16W,1% ,Chip,1/2W,1%2010 StdStd2R23,R2810 KResistor,Chip,1/16W,1% ,Chip,1/16W,1%0603 StdStd1R252 KResistor,Chip,1/16W,1% ,Chip,1/16W,1%0603 StdStd1R27604 Resistor,Chip,1/16W,1% ,Chip,1/16W,1%0603 StdStd2R3,R41 KResistor,Chip,1/16W,1% ,Chip,1/16W,1% ,Chip,1/16W,1% ,Chip,1/16W,1% ,Chip,1/16W,1%0603 StdStd4R8,R9,R10,75 Resistor,Chip,1/16W,1%0603 StdStdR111T1 ETH1-230 LDXFMR,Mid-PowerPoEMagneticsS014 WideETH1-230 LDCoilcraft1T2JA4456-DLTransformer,SMTFo rPoE/PD,25W.

8 , ,Optocoupler,70-V,300- 600%CTRSMT-4 PDIPFOD817 DSFairchild1U2 TPS23754 PWPIC, ,Photocoupler,3750 VRMS,80-160%CTRMF4 TCMT1107 Vishay1U4 TLV431 AIC,ShuntRegulator,6V,10mA,1%SOT23-5 TLV431 ACDBVRTI6 Shunt,Black100-mil929950-003M1 PCB, ,SynchronousFlyback, high -PowerPoESLVA475 January2012 Controller/ConverterSubmitDocumentationF eedbackCopyright 2012,TexasInstrumentsIncorporatedIMPORTA NTNOTICET exasInstrumentsIncorporatedanditssubsidi aries(TI)reservetherighttomakecorrection s,modifications,enhancements,improvement s, s accordancewithTI s ,testingofallparametersofeachproductis , ,eitherexpressorimplied,is grantedunderanyTIpatentright,copyright,m askworkright,orotherTIintellectualproper tyrightrelatingtoanycombination,machine, orprocessin licensefroma thirdpartyunderthepatentsorotherintellec tualpropertyofthethirdparty,ora TIdatabooksordatasheetsis permissibleonlyif reproductionis withoutalterationandis accompaniedbyallassociatedwarranties,con ditions,limitations, safety-criticalapplications(suchaslifesu pport)

9 Wherea failureoftheTIproductwouldreasonablybeex pectedtocauseseverepersonalinjuryordeath , thesafetyandregulatoryramificationsofthe irapplications,andacknowledgeandagreetha ttheyaresolelyresponsibleforalllegal,reg ulatoryandsafety-relatedrequirementsconc erningtheirproductsandanyuseofTIproducts in suchsafety-criticalapplications, , military/aerospaceapplicationsorenvironm entsunlesstheTIproductsarespecificallyde signatedbyTIasmilitary-gradeor"enhancedp lastic." solelyattheBuyer's risk,andthattheyaresolelyresponsibleforc ompliancewithalllegalandregulatoryrequir ementsin ,if theyuseanynon-designatedproductsin automotiveapplications, , :TexasInstruments,PostOfficeBox655303,Da llas,Texas75265 Copyright 2012,TexasInstrumentsIncorporat