prEN IEC 63758-5-5:2026

• Status: Not Published
• Publication Date: 23-Feb-2028
• Technical Committee: CLC/TC 100X - Audio, video and multimedia systems and equipment and related sub-systems
• Current Stage: 4020 - Enquiry circulated - Enquiry
• Start Date: 18-Sep-2026
• Completion Date: 18-Sep-2026
• Directive: 2014/53/EU - Directive 2014/53/EU of The European Parliament and of the Council of 16 April 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of radio equipment and repealing Directive 1999/5/EC
• Mandate: M/607 - COMMISSION IMPLEMENTING DECISION of C(2025)1207 on a Standardisation Request M/607 as regards charging interface and charging communication protocol for radio equipment capable of being recharged by means of wireless charging in relation with Article 3(4), sixth subparagraph, of Directive 2014/53/EU of the European Parliament and of the Council.
• Ref Project: oSIST prEN IEC 63758-5-5:2026 - Qi specification - Version 2.3 - Part 5-5: Mpp - Design guidelines (Informative) (Fast Track)

SLOVENSKI STANDARD
01-december-2026
Specifikacija Qi - Različica 2.3 - 5-5.del: Mpp - Smernice za načrtovanje
(informativno) (hitri postopek)
Qi specification - Version 2.3 - Part 5-5: Mpp - Design guidelines (Informative) (Fast
Track)
Ta slovenski standard je istoveten z: prEN IEC 63758-5-5:2026
ICS:
29.240.99 Druga oprema v zvezi z Other equipment related to
omrežji za prenos in power transmission and
distribucijo električne energije distribution networks
33.160.99 Druga avdio, video in Other audio, video and
avdiovizuelna oprema audiovisual equipment
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

100/4547/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 63758-5-5 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2026-09-18 2026-12-11
SUPERSEDES DOCUMENTS:
IEC TC 100 : AUDIO, VIDEO AND MULTIMEDIA SYSTEMS AND EQUIPMENT
SECRETARIAT: SECRETARY:
Japan Ms Mahiru Uehara
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
TC 106,TC 108
ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for
Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which they
are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries”
clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Qi Specification - Version 2.3 - Part 5-5: MPP - Design guidelines (Informative) (Fast Track)

PROPOSED STABILITY DATE: 2029
NOTE FROM TC/SC OFFICERS:
As this is a fast-track process offered by WPC, the Word file is not provided.

electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

QiSpecification
MPP–DesignGuidelines
(Informative)
Version2.3
PublishDate:08December2025
DISCLAIMER
Theinformationcontainedhereinisbelievedtobeaccurateasofthedateofpublication,butisprovided“asis”andmay
containerrors.TheWirelessPowerConsortiummakesnowarranty,expressorimplied,withrespecttothisdocument
anditscontents,includinganywarrantyoftitle,ownership,merchantability,orfitnessforaparticularuseorpurpose.
NeithertheWirelessPowerConsortium,noranymemberoftheWirelessPowerConsortiumwillbeliableforerrorsin
thisdocumentorforanydamages,includingindirectorconsequential,fromuseoforrelianceontheaccuracyofthis
document.Foranyfurtherexplanationofthecontentsofthisdocument,orincaseofanyperceivedinconsistencyor
ambiguityofinterpretation,contact:[e-mail].

Contents
1. General 6
1.1 StructureoftheQi Specification 6
1.2 Scope 7
1.3 Compliance 7
1.4 References 7
1.5 Conventions 8
1.5.1 Notationofnumbers 8
1.5.2 Tolerances 8
1.5.3 Fieldsinadatapacket 8
1.5.4 Notationoftextstrings 9
1.5.5 Short-handnotationfordatapackets 9
AnnexA: 10
A.1 PTxWorkingwithLegacyPRx 10
A.1.1 Background 10
A.2 MitigationofSaturationforBPP 11
A.2.1 SystemModel 11
A.2.2 SHOSpecifications 15
A.3 Loss-SplitModeling:Aframeworkforcalculatinglocalizededdy-currentlosses 16
A.3.1 Introduction 16
A.3.2 ComparisonbetweenthestandardT-ModelandLoss-SplitModel 17
A.3.3 DeterminingtheLoss-SplitModelParameters 18
A.3.4 CalculatingPowerLossusingLoss-SplitModel 20
A.4 ResistiveCouplingFactor 22
A.4.1 Introduction 22
A.4.2 DefinitionofMutualResistanceandKr 22
A.4.3 CauseofMutualResistance 24
A.4.4 WhyisKrnon-negligible 26
AnnexB: CoilSpecifications(Informative) 27
B.1 PRxCoilSpecifications 27
B.1.1 PRxCoilSpec2 27
B.1.2 PRxCoilSpec3 28
B.1.3 PRxCoilSpec4 29
B.1.4 PRxCoilSpec5 30
B.1.5 PRxCoilSpec6 31
B.1.6 PRxCoilSpec7 32
B.1.7 PRxCoil Spec8 33
B.1.8 PRxCoilSpec9 34
B.1.9 PRxCoilSpec10 35
B.1.10 PRxCoilSpec11 36
B.1.11 PRxCoilSpec12 37
B.1.12 PRxCoil Spec13 38
B.1.13 PRxCoilSpec14 39
B.1.14 PRxCoilSpec15 40
B.1.15 PRxCoilSpec16 41
B.1.16 PRxCoilSpec17 42
B.1.17 PRxCoilSpec18 43
B.1.18 PRxCoil Spec19 44
B.1.19 PRxCoilSpec20 45
B.1.20 PRxCoil Spec21 46
B.2 PTxCoilSpecifications 47
B.2.1 PTxCoil Spec3 47
B.2.2 PTxCoilSpec4 48
B.2.3 PTxCoil Spec5 49
B.2.4 PTxCoil Spec6 50
B.2.5 PTxCoilSpec7 51
B.2.6 PTxCoilSpec8 52
B.2.7 PTxCoil Spec9 53
B.2.8 PTxCoilSpec10 54
B.2.9 PTxCoil Spec11 55
B.2.10 PTxCoil Spec12 56
B.2.11 PTxCoilSpec13 57
B.2.12 PTxCoilSpec14 58
B.2.13 PTxCoilSpec15 59
B.2.14 PTxCoilSpec16 60
B.2.15 PTxCoilSpec17 61
B.2.16 PTxCoilSpec18 62
B.2.17 PTxCoilSpec19 63
B.2.18 PTxCoilSpec20 64
B.2.19 PTxCoilSpec21 65
B.2.20 PTxCoilSpec22 66
AnnexC: PRxDesignExamples 67
C.1 BuckChargers 67
C.2 SwitchedCapacitorCharger 68
C.3 PRxwithbothBuckandSWCChargers 72
C.4 DesignConsiderations 74
C.4.1 PowerModeTransitionforSWCChargers 74
C.5 DesignConsiderationsforWirelessChargingSystemusingSwitchedCapacitorCharger 75
C.5.1 Introduction 75
C.5.2 FindLQKRinMagneticBoundary 75
C.5.3 FirstHarmonicAnalysisofGainandPhase 79
C.5.4 SpiceCircuitSimulation 79
C.5.5 ComponentsToleranceAnalysis 81
C.6 Limitationsof25WSystemModel 82
C.6.1 Limitationwith16VMinimumInverterVoltage 82
C.6.2 SelectingHPMandNPMwith16VMinimumInverterVoltage 84

C.6.3 Limitationswith20VMaximumInverterVoltage 85
C.7 DesignConsiderationsforWLCSystemwithSWCCharger 87
C.7.1 PTxVoltageandPowerRangeRecommendations 87
C.7.2 PRxModeSelectionRecommendations 88
AnnexD: CapacitiveASKModulation 89
D.1 Introduction 89
D.2 GeneralcapacitiveASKModulation 90
D.2.1 IntroductionofCapacitiveASKmodulationscheme 90
D.2.2 ModellingfortheCapacitiveASKmodulation 90
D.2.3 ThevoltagegainanalysisfortheCapacitiveASKmodulation 93
D.2.4 TestresultsforthecapacitiveASKmodulation 95
D.2.5 TheoreticalAnalysisforthecapacitiveandloadcurrentASKmodulation 96
D.3 ThedesignprocessforthecapacitiveASKmodulation 97
D.4 NegativeCapacitiveASKModulation 98
D.4.1 NegativecapacitiveASKModulation 98
D.4.2 NegativeCapacitiveASKModulationwithintheOperatingWindow 99
D.4.3 ComparisonofNegativeCapacitiveASKModulationvsLoadModulation 102
D.4.4 MeasurementResultsof NegativecapacitiveASKModulation 104
D.4.5 NegativecapacitiveASKModulationDesignConsiderations 105

1. General
TheWirelessPowerConsortium(WPC)isaworldwideorganizationthataimstodevelopandpromoteglobalstandards
forwirelesspowertransferinvariousapplicationareas.Animportantapplicationareacomprisesflat-surfacedevices
suchasmobilephonesandchargersoperatingatpowerlevelsupto25W.
1.1 StructureoftheQi Specification
Generaldocuments
l
Introduction
l
Glossary,Acronyms,andSymbols
l
TechnicalSystemOverview
l
PowerProfiles
Systemdescriptiondocuments
l
Mechanical,Thermal,andUserInterface
l
PowerDelivery
l
CommunicationsPhysicalLayer
l
CommunicationsProtocol
l
ForeignObjectDetection
l
NFCTagProtection
l
AuthenticationProtocol
l
MPPCommunicationsProtocol
l
MPPMagneticsDesign
l
MPP PowerDelivery
l
MPP CommunicationsPhysicalLayer
l
MPP ForeignObjectDetection
l
MPP DesignGuidelines(Informative)
l
MagneticCovers
l
ActiveAlignmentSystem
l
ThermalManagementProtocol
1.2 Scope
TheQiSpecification,MPP DesignGuidelines(Informative)(thisdocument)detailsofinformativedesignguidelines
intendedtoimproveproductinteroperability.
NOTE:Thisbookcontainsnorequirementsforproductdesign.
1.3 Compliance
AllprovisionsintheQiSpecificationaremandatory,unlessspecificallyindicatedasrecommended,optional,note,
example,orinformative.VerbalexpressionofprovisionsinthisSpecificationfollowtherulesprovidedinISO/IEC
Directives,Part2.
Table1-Verbalformsforexpressionsofprovisions
Provision Verbalform
requirement “shall”or“shallnot”
recommendation “should”or“shouldnot”
permission “may”or“maynot”
capability “can”or“cannot”
1.4 References
Forundatedreferences,themostrecentlypublisheddocumentapplies.ThemostrecentWPCpublicationscanbe
downloadedfromhttp://www.wirelesspowerconsortium.com.

1.5 Conventions
1.5.1 Notationofnumbers
l
Realnumbersusethedigits0to9,adecimalpoint,andoptionallyanexponentialpart.
l
Integernumbersindecimalnotationusethedigits0to9.
l
Integernumbersinhexadecimalnotationusethehexadecimaldigits0to9andAtoF,andareprefixedby"0x"
unlessexplicitlyindicatedotherwise.
l
SinglebitvaluesusethewordsZEROandONE.
1.5.2 Tolerances
Unlessindicatedotherwise,allnumericvaluesintheQiSpecificationareexactlyasspecifiedanddonothaveany
impliedtolerance.
1.5.3 Fieldsinadatapacket
Anumericvaluestoredinafieldofadatapacketusesabig-endianformat.Bitsthataremoresignificantarestoredata
lowerbyteoffsetthanbitsthatarelesssignificant.Table2andFigure1provideexamplesoftheinterpretationofsuch
fields.
Table2-Exampleoffieldsinadatapacket(table)
b b b b b b b b
7 6 5 4 3 2 1 0
B (msb)
B 16-bitNumericDataField (lsb)
B OtherField
(msb)
B 16-bitNumericDataField (lsb)
Field
Figure1-Examplesoffieldsinadatapacket

1.5.4 Notationoftextstrings
TextstringsconsistofasequenceofprintableASCIIcharacters(i.e.intherangeof0x20to0x7E)enclosedindouble
quotes(").Textstringsarestoredinfieldsofdatastructureswiththefirstcharacterofthestringatthelowestbyte
offset,andarepaddedwithASCIINUL(0x00)characterstotheendofthefieldwherenecessary.
EXAMPLE: Thetextstring“WPC”isstoredinasix-bytefieldsasthesequenceofcharacters'W','P','C',NUL,NUL,and
NUL.Thetextstring“M:4D3A”isstoredinasix-bytefieldasthesequence'M',':','4','D','3',and'A'.
1.5.5 Short-handnotationfordatapackets
Inmanyinstances,theQiSpecificationreferstoadatapacketusingthefollowingshorthandnotation:
/
Inthisnotation,referstothedatapacket'smnemonicdefinedintheQiSpecification,Communications
Protocol,andreferstoaparticularvalueinafieldofthedatapacket.Thedefinitionsofthedatapacketsin
theQiSpecification,CommunicationsProtocol,listthemeaningsofthemodifiers.
Forexample,EPT/ccreferstoanEndPowerTransferdatapackethavingitsEndPowerTransfercodefieldsetto0x01.

AnnexA:
A.1 PTxWorkingwithLegacyPRx
A.1.1 Background
Incertainscenarios,anMPPPTxneedstotakeadditionalcaretoworkwithalegacyPRxthatimplementsthe
proprietaryprotocolthatMPPwasderivedfrom.Anexampleis"deadbatteryboot",wherethePRxhasanexhausted
batteryandrunsonaone-time-programmablefirmwareimagethatwascreatedbeforeMPPwasreleased.
ThefollowingrequirementspecifieswhatanMPPPTxneedstodointhissituation.
A.1.1.1 PTxMPP-LegacySpec1
AnMPPPTxshalloperateinMPPRestrictedmodewithanoperatingfrequencyof360kHz,whenallthefollowing
conditionsaremet:
l
IDpacketcontains:
l
"ManufacturerCode"setto0x005A
l
"Majorversion"setto0x1
l
"Minorversion"setto0x2
l
XIDpacketcontains:
l
"XIDSelector"(byteB0)setto0xFE,
l
"Restricted"(byteB1,bit7)settoONE,
InMPPrestrictedmode,duringthepowertransferphase:
l
PRxsendsCEPandRPpackets
PTxcontinuouslyadvertisesMPPcapability(seeMPPCommunicationsProtocol,section4.6)

A.2 MitigationofSaturationforBPP
ThisannexintroducesamitigationmethodthatanMPPPTxcanemploytomitigateferritesaturationproblemswitha
Qi1.3BPPPRx.TheintentionistoallowinitialandtemporarysupportofQi1.3BPPPRxproductsinthebeginningof
theQi2.0lifecycle.
A.2.1 SystemModel
A.2.1.1 Introduction
MPPenablesalignmentbetweenPTxandPRxviamagneticattach.TheDCmagneticfluxfromthepermanentmagnets
canresultinsaturationforsomepowerreceiverswithlowBsatferritefluxguides.Inparticular,theinteractionofthe
DCandACmagneticfluxcanleadtotime-dependentferritesaturation.Whentheferritesaturates,thematedinductance
dropsandlowerinductanceresultsinhighercoilcurrents.Thistime-dependentbehaviourcaninducesub-harmonic
oscillation(referhereinasSHO).SHOcanleadtoASKcommsfailureandpossibledisconnects.
Figure2showstwoexamplesofthePTxcurrentwaveform:withandwithoutSHO.SHOismarkedbyapatternofevery
otherpositivecyclehavingexcessivecurrentfollowedbythenextpositivecyclehavingdiminishedcurrent.
Figure2-ComparisonofPTxcurrentwithandwithoutSHO.
SHOstartstooccuratpowerlevelsthatarehighenoughsuchthatthecombinedDCandACfluxcausesferrite
saturation.Belowthatpowerlevel,SHOdoesnotoccur.Toprovide5WBPPperformancetoallQireceivers,eveninthe
caseofferritefluxguides,thissectionprovidesasuggestedapproachforSHOmitigationandtheapproachtakenbythe
systemmodel.Thisapproachinvolvestwosteps:
1. SHODetection
2. SHOMitigation
A.2.1.2 SHODetection
AsindicatedinFigure2,SHOhasawell-definedsignatureofwheretheamplitudevarieseveryothercycle.Thiscanbe
detectedinmanyways.Exampledetectionschemesinclude:
Frequencydomainapproach:
Measuretheenergyat /2andcompareittotheenergyat .
l Agooddetectioncriteriais: toindicatetheonsetofSHO.
Timedomainapproaches:
Computethepeak-to-valleyoverpowercycles:
where
l
ThendeclareSHOif
l
standarddeviationof computedoverNcyclesexceedsathreshold(~1.25%),orif
l averageof overNcyclesexceedsathreshold(~2.5%)
Alternatively,computepeak-to-valleychangesoverNgroupsofpowercycles:
l
ThendeclareSHOif
l averagevalueof exceedsathreshold(~2.5%)
It’simportantthattheSHOdetectionalgorithmberobustandavoidfalsepositivedetections.Toensurethis,two
safeguardsarerecommended.First,forsufficientlylowpowerlevels,SHOdetectionisdisabled.Thatistoprevent
instabilitiesornoiseinthelowsignallevelsfromtriggeringafalsedetectionatpowerlevelsbelowthelevelwhereSHO
canbeinduced.Second,somenumberofconsecutivedetectionsisrequiredbeforeSHOisdeclared.Theoverall
algorithmisdescribedbytheflowchartinFigure3.Inthesystemmodel,thefrequency-domainapproachisused.
Figure3-SystemModelSHOdetectionflowchart.

AfterXCEpacketisreceivedand"actedupon"indicatesthatFWhasreceivedpositiveindicationthat orinverter
phasehasbeenadjustedaccordingtotheXCEpacket.
Inthesystemmodel,theentranceconditionis:
l
P >3.5W,or
IN
l
θ(PTxinverterphaseshift)<110º
A.2.1.3 SHOMitigation
Figure4-SystemModelSHOmitigationflowchart.
OnceSHOisdetected,variousoptionsareavailabletoreduceoreliminatetheSHO:
1. ReduceV
in
2. IncreasephasewhileallowingV toincrease
in
3. Reduceon-timeofpositivehalf-cycle
Alltheseoptions,takenbythemselveswillreducepower;butoptions2and3allowthepossibilityofallowingincreases
in toprovideincreasedpowerdelivery.
TheflowchartinFigure4showstheimplementationofthesystemmodel(usingoption2).
InFigure4,thephaseisincreaseduntilSHOisremoved.WhenSHOisremoved,theXCEactionisfreetoincrease
butnolongercanitincreasephase.IfSHOisagaindetected,phasewillbefurtherincreasedsolongasitremainsbelow
PHASE_MAX(areasonablevalueforPHASE_MAXis120°).Oncephasegetstoitsminimum, willbedecreaseduntil
SHOiseliminatedafterwhichpoint, cannolongerbeincreased.

A.2.1.4 InteractionwithRPP
Ferritesaturationcanalsoleadtoadditionalfriendlymetallosses.Thisadditionallosscanresultinanunder-estimation
ofreceiver-sidelossesasreportedintheRP8packet.Therefore,ifSHOisdetecteditisreasonableforthepower
transmittertoincreasethereceiversidelossby
inthesystemmodel, is350mW.
ForapracticalPTxdesign, shouldbedeterminedtoreflectitsspecificmagneticsdesign.Belowisanexample
methodologytoexperimentallydetermine byfindingthemaximumunaccountednon-linearlossduetoferrite
saturationamongasetofPRxdeviceswithferriteshields:
1. PickaBPPPRx,mateditwithPTxatposition(0,0);
2. IfSHOisn'tdetected,skipthisPRxandadvancetostep1againwiththenextPRx;
3. CalculateforeignobjectpowerP ;
FO1
4. MovethePRxalongthezaxisuntilatposition(0,z0)whereSHOisnolongerdetected,recordP andcalculate
FO2
∆P=P -P ;
FO2 FO1
5. Repeat1-2forapoolofPRxdevicesandpickthemaximum∆Pvalueas
A.2.2 SHOSpecifications
A.2.2.1 PTxSHOSpec1
PTxshallbeabletodeliverpowertoTPR#8.
NOTE:TPR#8isatestreceiverwithamagneticshieldingdesignedtosaturateonTPT#MPP1andoperatesinBPPmode.

A.3 Loss-SplitModeling:Aframeworkforcalculatinglocalizededdy-currentlosses
A.3.1 Introduction
Theloss-splitmodelwasfirstpresentedatWPC19-03withthetitle"Loss-SplitModel-Aframeworkforcalculating
localizedlosses"andhasbeensummarizedinthissection.Inawirelesspowersystem,themagneticfieldproducedby
thecoilsproducelossesinmanyplaces:resistivelossesinthecoppercoilsthemselves,inthePRxfriendlymetal,the
PTxfriendlymetalandinanyforeignobjects(ifpresentandmetallicorpermeable).InthePowerLossAccounting
(PLA)ForeignObjectDetection(FOD)method,weaimtoaccuratelymodelandpredictlossesinthePTxandPRxsothat
anyunexplainedlosscouldbeattributedtothepresenceofaForeignObject(FO)andanappropriateresponsecanbe
takenbythePTxtopreventover-heatingoftheFO.
InMPPPowerLossAccounting(MPLA),asimulation-basedflowisusedtodeterminetheparametersoftheMPLAloss
model.Thesimulation-basedapproachprovidesincreasedgranularityofthedifferentlossesinthewirelesspower
systemandallowsustomodeleachlosscomponentmoreaccurately.Thisalsoenablestheapplicationoftemperature
compensationtolosscomponentsandenablesustomodeltheimpactofparameterdriftovertheproductlifetime.
ToanalysethelossescausedbytheACmagneticfields,thesimulation-basedflowinFigure5wasfirstinvestigated.
However,itwasfoundtobeimpracticalbecauseofthenested"RunFEAsimulation"intheflow,whichisveryslowand
computationallyintensesteptorepeatacrossthestate-space.Theloss-splitmodelingflowwasdesignedtoovercome
thislimitationandisshowninFigure6.Bymovingthe"RunFEA"stepintoanouterloop(decoupledfromelectrical
operatingpoints),thenumberofFEAsimulationsrequiredcanbedrasticallyreducedwhilestillallowingforallthe
differentlosscomponentstobeseparated.
Figure5-Simulationbasedpoweraccountingflow.

Figure6-Loss-SplitPowerAccountingFlow.
A.3.2 ComparisonbetweenthestandardT-ModelandLoss-SplitModel
ItispossibletoextractacircuitmodelfromtheFEAsimulationsorthes-parametermeasurementsofmatedPTxand
PRxcoils.ThestandardT-ModelisshowninFigure7.Theproblem,however,isthattheparametersR1,R2andR3are
non-physicalandlumpallthedifferentlossestogether.Fromtheseparameters,wecannotdeterminehowmuchloss
occursinthecoppercoils,thefriendlymetaloranFO(ifpresent)andthismakesitimpossibletodetermineifthe
powerlostinanFOisabovetheheatingthresholdthroughcircuitsimulation.ComparethistotheLoss-Split-Model
showninFigure8.HerewecanseethatR1,R2andR3havebeenbrokenoutintoconstituentresistancesassociatedwith
thePRxfriendlymetal,PRxcoil,PTxfriendlymetal,PTxcoilandtheFO.Oncetheseparametershavebeendetermined,
theelectricaloperatingconditionscaneasilybevariedthroughcircuitsimulationandtheriskofFOover-heatingcanbe
evaluatedfordifferentoperatingpointsandconditions.
Figure7-StandardT-Model.
Figure8-Loss-SplitT-Model.
A.3.3 DeterminingtheLoss-SplitModelParameters
DeterminingtheLoss-SplitModelparametersisathreestepprocess:
1. RunFEAsimulationswiththreedifferentstimulationcases
2. Determinepowerlostdifferentphysicalbodies(coilcopper,friendlymetal,FO)foreachcaseinstep1
3. Solveforloss-splitresistancesusingresultsfromstep1andstep2
Inthistheremainderofthissection,eachofthesestepswillbecoveredinmoredetail.
Step1.RunFEASimulations
TosolvefortheresistancesonallbranchesoftheT-Model,aminimumofthreeFEAsimulationcasesarerequired.The
conditionsforthesesimulationsareshowninTable3.
Table3-FEA simulationconditions.
FEACases Case1 Case2 Case3
Amplitude I_TX=1,I_RX=0 I_TX=0,I_RX=1 I_TX=1,I_RX=1
(Phasedifference=0
degrees)
RMS^2 I_TX=0.5 I_TX=0 I_TX=0.5
I_RX=0 I_RX=0.5 I_RX=0.5
(I_TX+I_RX)^2=2
Step2.DeterminePowerLoss
Foreachcaseinstep1,extractthepowerlostineachoftheregionsofinterest.
AnexampleisprovidedinFigure9.
Figure9-Regionsforpowerlossestimation
Thepowerlossesineachregioncanberepresentedbythefollowingequations:
Figure10-Equationsforpowerlossestimation
Step3.SolveforResistances
Theresultsfromstep1andstep2canbeusedtosolveforalltheresistances

A.3.4 CalculatingPowerLossusingLoss-SplitModel
InSectionA.3.3,DeterminingtheLoss-SplitModelParameters,wedeterminedalltheresistancesintheloss-splitmodel.
Thiscanthenbeusedincircuitsimulationtodeterminewhatthepowerlossindifferentphysicalregionswouldbe
underawidevarietyofoperatingconditions.Thepowerlostineachregioncanbecalculatedusingtheequationsshown
inFigure9:
Figure11-Loss-splitmodelparameters
Thevalidationresultsoftheloss-splitmodelwaspresentedatWPC19-03andisshowninFigure9
Thisdemonstratesthattheloss-splitmodelmethodologyenablesaccurateandrapidassessmentsofFOover-heating
riskforawidevarietyofcircuitoperatingconditionsandphysicalplacementscenarios.

Figure12-Validationresultsoftheloss-splitmodel

A.4 ResistiveCouplingFactor
A.4.1 Introduction
Theresistivecouplingfactor isanimportantparametertocharacterizeanMPPcoildesign(seetheMPPMagnetics
Designbook ).Thisannexexplains:
l
Thedefinitionandphysicalexplanationof
l
Whyis non-negligible
A.4.2 DefinitionofMutualResistanceandKr
Inacoupledinductormodel,withnomutualresistance,theopen-circuitinducedvoltagev onthesecondaryside
s
alwayshasa90°phaseoffsetfromtheprimarycurrenti.ThisisadirectconsequenceofFaraday'slaw.However,in
p
practice,thereareusuallyobjectsaroundwithnon-negligibleelectricalconductivityormagneticcoercivity.Theydistort
v suchthatit'snolongerperfectly90°offfromi (theexactcauseisdiscussedinSectionA.4.3,CauseofMutual
s p
Resistance).Mutualresistanceisintroducedtocapturethecomponentofv thathasthesamephasewithi (SeeFigure
s p
13):
Equation:1
Figure13-MutualResistanceModelataSingleFrequency.
Becausetheinductivelinkissymmetric,thesameappliestotheoppositedirection(i.e.,"primary"sidecanbeeither
transmitterorreceiver).Fromthemutualinductance,theresistivecouplingfactorisdefinedasaunitlessquantity:
Equation:2
Unlikemutualcoupling, isnotboundedto[0,1].Infact, canevenbenegative--aphysicalexplanationofan
exampleofnegative isgiveninSectionA.4.3.1.1,PhysicalMeaningofaNegativeMutualResistance .
Ingeneral, isfrequencydependent,i.e.,denotedas (f)or (ω).Weusuallyuse casuallytorefertoitsvalueat
360kHz.
A.4.2.1 Lossassociatedwithmutualresistance
Atanygivenfrequency,thetotallossinthemagneticmodelisgivenby
Equation:3
where
l
, arethephasorsofPTxandPRxcurrentsatthegivenfrequency,
l takesthecomplexconjugateand takestherealpartofacomplexnumber.
Equation:3statesthatmutualinductancecapturesthecross-losstermthatiscollaborativelycontributedbybothPTx
andPRxcurrents.Thisisthecasewhenthereareobjects,forexample,friendlymetalorferromagneticshields,that
electromagneticallyinteractwithbothPTxandPRxcoils.
Equation:3ismathematicallyequivalentwithEquation:1,andcanbeusedasanalternativedefinitionofmutual
resistance.
A.4.3 CauseofMutualResistance
Therearetwomaincausesofmutualresistances:
l
eddycurrentduetoelectricallyconductiveobjects
l
hysteresisduetomagneticallycoerciveobjects
Notcoincidentally,theyarethesamephysicalphenomenabehindforeignobjectlossaswell.
A.4.3.1 EddyCurrentCause
EddycurrentsonaconductiveobjectincloseproximitytobothPTxandPRxleadtomutualinductance.Perhapstomost
intuitivewaytounderstandthisistolookatthelossandusethelossdefinition(Equation:3)ofmutualresistance.
Saythereisanelectricallyconductiveobject,andbothPTxandPRxcurrentscaninduceeddycurrentsonit.Andfor
simplicityletuskeepthefirst-orderterms,i.e.,theeddycurrentinducedbyPTxis
where isthephasornotationofPTxcurrent,andaisconstantwhosevalueisirrelevanttooutdiscussionhere.Similar,
theeddycurrentinducedbyPRxis
where,again,bisanunknownconstant.Sincetheelectricalfieldisadditive,thenthetotaleddycurrentis
So,thetotallossis
Equation:4
(e)
(i)
whereR istheequivalentresistanceoftheeddycurrentpath.
Equation:4matcheswiththelossdefinitionofmutationresistance(Equation:3),wherethemutualinductanceisequal
* (e)
toabR .
A.4.3.1.1 PhysicalMeaningofaNegativeMutualResistance
AnegativemutualresistanceispossibleiftheeddycurrentsinducedontheelectricallyconductiveobjectbythePTx
andPRxaddupnon-constructively.Forexample,theycouldbeinoppositedirections,orwithanangle>90°.Thisledto
anegativecross-terminEquation:4,andconsequently,anegativemutualresistance.
(i)
Tobemoretechnicallyaccurate,theanalysisneedstobedonewithconductivityσandelectricalfieldE,butthe
derivationisverysimilar.Additionally,theequationassumesthataandbareeitherin-phaseor180°out-of-phase,
whichisreasonableconsideringfirst-ordereffects.Otherwise,therewillbeafourthtermthatisrelatedtotheimaginary
*
componentof .
A.4.3.2 HysteresisCause
Tounderstandhowmagnetichysteresiscausesanon-zeromutualinductance,wecaninspecttheadditionalphaseshift
causedbythenon-linearB-Hcurveandusethephase-shiftdefinitionofmutualresistance(Equation:1):
ConsiderthecasewherePTxcoilisexcitedwithcurrent,andPRxcoilisopen.Additionally,thereisferromagnetic
materialinthecloseproximityofbothcoils,withanonlinearB-Hcurveandanon-negligiblecoercivity.Forsimplicity,
letusassumethatthePRxvoltagev issinusoidal.Therefore,accordingtoFaraday'slaw,theBfieldisproportionalto
rx
theintegralofv andissinusoidalaswell.SincetheB-Hcurveisnon-linear,andtheHfieldisdirectlyproportionalto
rx
thePTxcurrent , isnotsinusoidalanditsfundamentalcomponentisoutofphasewiththeintegralofv (SeeFigure
rx
14).TheisexactlyhowmutualresistancewasintroducedinSectionA.4.2,DefinitionofMutualResistanceandKr to
capturetheout-of-phasecomponentbetween andtheintegralofv .
rx
Figure14-Non-linearB-HcurveintroducesphaseoffsetbetweenPTxcurrentandtheintegralofPRxinduced
voltage,wheretheout-of-phasecomponentiscapturedbymutualresistance.

A.4.4 WhyisKrnon-negligible
AsdiscussedinSectionA.4.3,CauseofMutualResistance,anyelectricalconductivematerialand/orferromagnetic
materialwithhysteresiswilladdtothemutualresistance.InatypicalMPPsystem,thesematerialsarecommon:for
example,thefriendlymetalusedincoilassemblyandinthedeviceitself,andferromagneticshieldsusedinbothPTx
andPRxcoils.
Figure15plotsthemeasured valuesfromamatedMPPPTx/PRxcoilsample.Itshowsthat:
l Themagnitudeof isnon-negligible.Evenat(2,2),it'smorethan75%oftheself-resistanceonthePTx/PRx
coil.
l
generaldecreaseswithincreasingpositionaloffset.Thisisbecausethefriendlymetalobjectsandmagnetic
shieldsarefurtherawaywithincreasingpositionoffset.
Figure15-Examplevaluesof measuredwithamatedMPPPTx/PRxcoilsample.

AnnexB: CoilSpecifications(Informative)
Thefollowingcoilspecificationsshowexamplesofexpectedmagneticboundariesbetweencertifiedproductsonthe
market.RefertotheMPPMagneticsDesignbook formagneticboundaryrequirements.
B.1 PRxCoilSpecifications
B.1.1 PRxCoilSpec2
TheinductanceofthePRxcoilmodulewhenitismatedwithPTxatposition(0,0)at360kHz, ,shouldfitwithin
theboundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation:
where:
l and areinmicrohenries
=14.6
l
l =17.7
l
a=4.1
l
b=1.35
l
α=–0.6449
L ’
r
B.1.2 PRxCoilSpec3
TheinductanceofPRxcoilmodulewhenitismatedwithPTxatposition(2,2)at360kHz, ,shouldfitwithinthe
boundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation.
where:
l and areinmicrohenries
=10.0163
l
l =11.6602
l
a=2.0867
l
b=0.85
l
α=–0.3364
L ’
r
B.1.3 PRxCoilSpec4
TheACresistancebetweenthecoilterminalsofthePRxcoilmodulewhenitismatedwithPTxatposition(0,0)at360
kHz, ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (0,0) at 360 kHz
RX TX
2.5
0.5
0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
R ’ (Ω)
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’ (Ω)
r
B.1.4 PRxCoilSpec5
TheACresistancebetweenthecoilterminalsofthePRxcoilmodulewhenitismatedwithPTxatposition(2,2)at360
kHz, ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (2,2) at 360 kHz
RX TX
1.8
1.6
1.4
1.2
0.8
0.6
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
R ’ (Ω)
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’
(Ω)
r
B.1.5 PRxCoilSpec6
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(0,0)at360kHz, ,givenan ,should
fitwithintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.8895
=14.7
l
l
a=2.82
l
b=0.03
l
α=–0.011
L ’
t
B.1.6 PRxCoilSpec7
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(2,2)at360kHz, ,givenan shouldfit
withintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.702
=10.04
l
l
a=1.07
l
b=0.035
l
α=–0.029
L ’
t
B.1.7 PRxCoil Spec8
TheresistivecouplingbetweenPRxcoilmoduleandPTxatposition(0,0), ,shouldbewithin0.78498and0.93432
whenmeasuredat360kHz.
B.1.8 PRxCoilSpec9
TheresistivecouplingbetweenthePRxcoilmoduleandPTxatposition(2,2), ,shouldbewithin0.642and0.8578
whenmeasuredat360kHz.
B.1.9 PRxCoilSpec10
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(0,0)at360kHz, ,givenan ,should
fitwithintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.887
l =17.6
l
a=3.5
l
b=0.031
l
α=–0.0088
L ’
r
B.1.10 PRxCoilSpec11
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(2,2)at360kHz, ,givenan ,should
fitwithintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.7002
=11.6781
l
l
a=2.194
l
b=0.0421
l
α=–0.0104
L ’
r
B.1.11 PRxCoilSpec12
TheinductanceofPRxcoilmodulewhenitismatedwithPTxatposition(0,0)at128kHz, ,shouldfitwithinthe
boundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation:
where:
l and areinmicrohenries
=14.8551
l
=17.8023
l
l
a=3.4704
l
b=0.9748
l
α=–0.5926
L ’
r
B.1.12 PRxCoil Spec13
TheinductanceofPRxcoilmodulewhenitismatedwithPTxatposition(2,2)at128kHz, ,shouldfitwithinthe
boundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation:
where:
l and areinmicrohenries
=9.9548
l
l =11.5261
l
a=1.7311
l
b=0.6884
l
α=–0.3473
L ’
r
B.1.13 PRxCoilSpec14
TheACresistancebetweenthecoilterminalsofthePRxcoilmodulewhenitismatedwithPTxatposition(0,0)at128
kHz, ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (0,0) at 128 kHz
RX TX
1.1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
R’ (Ω)
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’ (Ω)
r
B.1.14 PRxCoilSpec15
TheACresistancebetweenthecoilterminalsofthePRxcoilmodulewhenitismatedwithPTxatposition(2,2)at128
kHz, ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (2,2) at 128 kHz
RX TX
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.05 0.1 0.15 0.2 0.25 0.3 0.35
R ’
(Ω)
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’ (Ω)
r
B.1.15 PRxCoilSpec16
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(0,0)at128kHz, ,givenan ,should
fitwithintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.8885
=14.827
l
l
a=2.1543
l
b=0.0164
l
α=–0.013
L ’
t
B.1.16 PRxCoilSpec17
TheresistivecouplingbetweenPRxcoilmoduleandPTxatposition(0,0), ,shouldbewithin0.61893and0.81192
whenmeasuredat128kHz.
B.1.17 PRxCoilSpec18
TheresistivecouplingbetweenPRxcoilmoduleandPTxatposition(2,2), ,shouldbewithin0.5167and0.6845
whenmeasuredat128kHz.
B.1.18 PRxCoil Spec19
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(0,0)at128kHz, ,givenan ,should
fitwithintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.8889
=17.7432
l
l
a=3.0096
l
b=0.0182
l
α=–0.0095
L ’
r
B.1.19 PRxCoilSpec20
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(2,2)at128kHz, ,givenan ,should
fitwithintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.6999
=11.4514
l
l
a=1.8492
l
b=0.0402
l
α=–0.0132
L ’
r
B.1.20 PRxCoil Spec21
ThemagneticcouplingbetweenthePRxcoilmoduleandPTxatposition(2,2)at128kHz, ,givenan  ,should
fitwithintheboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.7011
=9.9551
l
l
a=0.8876
l
b=0.0262
l
α=–0.0366
L ’
t
B.2 PTxCoilSpecifications
B.2.1 PTxCoil Spec3
TheinductanceofPTxcoilmodulewhenitismatedwiththePRxatposition(0,0)at360kHz, ,shouldfitwithin
theboundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation:
where:
l and areinmicrohenries
=14.6
l
l =17.7
l
a=4.1
l
b=1.35
l
α=–0.6449
L ’
r
B.2.2 PTxCoilSpec4
TheinductanceofPTxcoilmodulewhenitismatedwiththePRxatposition(2,2)at360kHz, ,shouldfitwithin
theboundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation:
where:
l and areinmicrohenries
=10.0163
l
=11.6602
l
l
a=2.0867
l
b=0.85
l
α=–0.3364
L ’
r
B.2.3 PTxCoil Spec5
TheACresistancebetweenthecoilterminalsofthePTxcoilmodulewhenitismatedwiththePRxatposition(0,0)at
360kHz, ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (0,0) at 360 kHz
RX TX
2.5
0.5
0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
R ’
(Ω)
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’ (Ω)
r
B.2.4 PTxCoil Spec6
TheACresistancebetweenthecoilterminalsofthePTxcoilmodulewhenitismatedwiththePRxatposition(2,2)at
360kHz, ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (2,2) at 360 kHz
RX TX
1.8
1.6
1.4
1.2
0.8
0.6
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
R ’
(Ω)
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’ (Ω)
r
B.2.5 PTxCoilSpec7
ThemagneticcouplingbetweenthePTxandthePRxatposition(0,0)at360kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to  boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.8895
=14.7
l
l
a=2.82
l
b=0.03
l
α=–0.011
L ’
t
B.2.6 PTxCoilSpec8
ThemagneticcouplingbetweenthePTxandthePRxatposition(2,2)at360kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.702
=10.04
l
l
a=1.07
l
b=0.035
l
α=–0.029
L ’
t
B.2.7 PTxCoil Spec9
ThemagneticcouplingbetweenthePTxandthePRxatposition(0,0)at360kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.887
=17.6
l
l
a=3.5
l
b=0.031
l
α=–0.0088
L ’
r
B.2.8 PTxCoilSpec10
ThemagneticcouplingbetweenthePTxandthePRxatposition(2,2)at360kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.7002
=11.6781
l
l
a=2.194
l
b=0.0421
l
α=–0.0104
L ’
r
B.2.9 PTxCoil Spec11
TheresistivecouplingbetweenPTxandthePRxatposition(0,0), ,shouldbewithin0.78498and0.93432when
measuredat360kHz.
B.2.10 PTxCoil Spec12
TheresistivecouplingbetweenPTxandthePRxatposition(2,2), ,shouldbewithin0.642and0.8578when
measuredat360kHz.
B.2.11 PTxCoilSpec13
TheinductanceofPTxcoilmodulewhenitismatedwiththePRxatposition(0,0)at128kHz, ,shouldfitwithin
theboundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation:
where:
l and areinmicrohenries
=14.8551
l
=17.8023
l
l
a=3.4704
l
b=0.9748
l
α=–0.5926
L ’
r
B.2.12 PTxCoilSpec14
TheinductanceofPTxcoilmodulewhenitismatedwiththePRxatposition(2,2)at128kHz, ,shouldfitwithin
theboundarydefinedbelow.
L ’
t
The to boundaryisdescribedwiththeequation:
where:
l and areinmicrohenries
=9.9548
l
=11.5261
l
l
a=1.7311
l
b=0.6884
l
α=–0.3473
L ’
r
B.2.13 PTxCoilSpec15
TheACresistancebetweenthecoilterminalsofthePTxcoilmodulewhenitismatedwiththePRxatposition(0,0)at
128kHz ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (0,0) at 128 kHz
RX TX
1.1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
(Ω)
R’
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’ (Ω)
r
B.2.14 PTxCoilSpec16
TheACresistancebetweenthecoilterminalsofthePTxcoilmodulewhenitismatedwiththePRxatposition(2,2)at
128kHz, ,shouldfitwithintheboundarydefinedbelow.
' '
R vs R at position (2,2) at 128 kHz
RX TX
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.05 0.1 0.15 0.2 0.25 0.3 0.35
R ’ (Ω)
t
Therelationshipbetween ,and ,canalsobedescribedwiththefollowingequation:
where:
l and areinohms
l
R ’ (Ω)
r
B.2.15 PTxCoilSpec17
ThemagneticcouplingbetweenthePTxandthePRxatposition(0,0)at128kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.8885
=14.827
l
l
a=2.1543
l
b=0.0164
l
α=–0.013
L ’
t
B.2.16 PTxCoilSpec18
ThemagneticcouplingbetweenthePTxandthePRxatposition(2,2)at128kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l isinmicrohenries
l =0.7011
=9.9551
l
l
a=0.8876
l
b=0.0262
l
α=–0.0366
L ’
t
B.2.17 PTxCoilSpec19
ThemagneticcouplingbetweenthePTxandthePRxatposition(0,0)at128kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.8889
=17.7432
l
l
a=3.0096
l
b=0.0182
l
α=–0.0095
L ’
r
B.2.18 PTxCoilSpec20
ThemagneticcouplingbetweenthePTxandthePRxatposition(2,2)at128kHz, ,givenan ,shouldfitwithin
theboundarydefinedbelow.
k
The to boundaryisdescribedwiththeequation:
where:
l
isinmicrohenries
l =0.6999
=11.4514
l
l
a=1.8492
l
b=0.0402
l
α=–0.0132
L ’
r
B.2.19 PTxCoilSpec21
TheresistivecouplingbetweenPTxandthePRxatposition(0,0), ,shouldbewithin0.61893and0.81192when
measuredat128kHz.
B.2.20 PTxCoilSpec22
TheresistivecouplingbetweenPTxandthePRxatposition(2,2), ,shouldbewithin0.5167and0.6845when
measuredat128kHz.
AnnexC: PRxDesignExamples
C.1 BuckChargers
ForsomewirelesschargingPRx,theoutputnodeistheRectifier’soutput .SomeotherwirelesschargingPRxICs
includeanLDO,andthePRxIC’soutputnodeistheLDOoutputVout.
Between (orLDOVout)andthebattery,thereisusuallyaBuck-typecharger(orasimilarswitchmodecharger
withaninductor)asshowninFigure16.
Figure16-PRxwithaBuckBatteryCharger.
ForBuckchargers,thereisnotastrictrelationshipbetween andbatteryvoltage.Therefore,PRxhasmorefreedom
todecideforthebest targetforthesystem.TheintendedrectifiedvoltageregulationrangeofaPRxwithabuck
chargerispresentedasanexampleinFigure17.
l Rectifiedvoltagetargetisselectedbasedon foroptimalwirelesslinkefficiencyandtolimitmaxover
voltageduringloadtransients.
l
Theinitial targetisselectedasdetailedinthe"Gain Measurement"sectionintheMPPPowerDeliverybook. .
Figure17-SystemmodelPRxVrect_target/PRECTprofile
ThisVrect_targetprofile
l
useshigherVrect_target,and
l
adaptivelychangesVrect_targetinsteadofusingfixedlevels.
Thesechangeshelptoimproveefficiencyandachievehigherpeakpowerandhigherthermallysustainedpower.

Figure18-TSL(ThermallySignificantLoss)vsRectifiedPower( )
C.2 SwitchedCapacitorCharger
Toachievehigherchargingefficiencyandreducethechargerloss,somePRxdevicesimplementaswitched-capacitor
charger(SWC)asshowninFigure19.Theinputvoltageoftheswitched-capacitorchargerisusuallyNtimesofthe
batteryvoltagewithsomeheadroom,withNbeinganinteger.Forhighpowerwirelesschargingarchitecture,N=4isa
commonchoiceandithasbeenimplementedinmanyexistingPRxdevices.
Figure19-PRxwithaSwitch-CapCharger(SWC)
Thesimplifie
...