oSIST prEN IEC 63758-5-2:2026

• Status: Not Published
• Public Enquiry End Date: 29-Nov-2026
• ICS: 29.240.99 - Other equipment related to power transmission and distribution networks
• ICS: 33.160.99 - Other audio, video and audiovisual equipment
• ICS: 35.200 - Interface and interconnection equipment
• Technical Committee: AVM - Audio, video and multimedia systems and equipment
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 28-Sep-2026
• Due Date: 15-Feb-2027
• 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: prEN IEC 63758-5-2:2026 - Qi specification - Version 2.3 - Part 5-2: Mpp - Power delivery (Fast Track)

oSIST prEN IEC 63758-5-2:2026 is a SIST publication identical to prEN IEC 63758-5-2:2026, the Qi specification Version 2.3 Part 5-2 for MPP - Power delivery. It specifies how Qi MPP Power Transmitter (PTx) and Power Receiver (PRx) designs manage power profiles, resonant tuning, digital pings, coupling estimation, gain measurement, closed-loop control, and over-voltage protection for wireless power transfer up to 25 W.

Engineers use this part to check whether a Qi MPP design can advertise, negotiate, and deliver the intended power in the right operating mode. Quality teams and buyers use it to understand what a compliant MPP implementation is expected to do in practice, especially at the interface between the transmitter, receiver, and power adapter.

What does oSIST prEN IEC 63758-5-2:2026 specify?

oSIST prEN IEC 63758-5-2:2026 covers guidelines and requirements for Power Receiver design, including circuitry, power consumption, operating power levels, power transfer efficiency, and standby power. Unless stated otherwise, its technical content applies to power delivery in MPP mode rather than BPP mode.

The document is organized into a general section and technical clauses that move from power profiles to control and protection:

• Clause 1 covers the structure of the Qi Specification, compliance language, references, and notation.
• Clause 2 covers PowerDelivery and the BPP and MPP power profiles.
• Clause 3 covers PowerModes and how the system uses different operating modes.
• Clause 4 covers the PowerReceiverFunctionalBlockDiagram.
• Clause 5 covers the PowerTransmitterFunctionalBlockDiagram.
• Clause 6 covers OperatingFrequency.
• Clause 7 covers ObjectDetection.
• Clause 8 covers DigitalPings128kHz/360kHz.
• Clause 9 covers KEstimation.
• Clause 10 covers OutputImpedance and Load Transients.
• Clause 11 covers GainMeasurement.
• Clause 12 covers PowerTransferControl.
• Clause 13 covers Mitigation of Side Effects of Cdat MPP Frequency.
• Clause 14 covers Over-voltage Protection in PRx.
• Clauses 15 to 17 cover Cloak, Common-mode Noise, and GG Value Definitions.

What are the key requirements of oSIST prEN IEC 63758-5-2:2026?

The core requirements define what power a Qi MPP pair must deliver, how it advertises and selects power modes, how it tunes resonance, and how it controls voltage and protection in real operation.

Power delivery targets in Clause 2

Clause 2 sets the power-delivery baseline for BPP and MPP operation. It requires specified rectified power delivery in defined alignment volumes, includes special rules for MPP Restricted Mode, and adds higher-power requirements for MPP25 PTx and PRx variants. In practice, this tells a designer what power level the link must sustain and in what geometric window the performance has to be guaranteed.

Power modes and advertised operating ranges in Clause 3

Clause 3 defines Default Power Mode (DPM), Low Power Mode (LPM), Nominal Power Mode (NPM), High Power Mode (HPM), and Continuous Power Mode (CPM). The PTx advertises supported modes in MODEXCAP, the advertised power levels must be ordered so that HPM is above NPM and NPM above LPM, and a PTx that supports CPM shall not support the discrete low, nominal, and high modes. In practice, this is the part that tells implementers what operating bands they may offer and how they must describe them to the receiver.

Mode transition behavior in Clause 3

Clause 3 also defines how the PRx moves between modes based on estimated coupling and observed load power. The model uses fast and slow transition thresholds, and once the system reaches nominal power mode it does not return to high power mode until power is removed by an EPT or CLOAK packet. In practice, this keeps mode changes tied to measured behavior instead of ad hoc firmware decisions.

Receiver and transmitter functional behavior in Clauses 4 and 5

Clauses 4 and 5 describe the PRx and PTx circuit models that support BPP compatibility and MPP operation. The PRx uses a series tuning network, a parallel resonant path for detection, and a rectifier, while the PTx uses a full-bridge converter with voltage control and phase-shift control. In practice, these clauses tell designers how the magnetic and power stages are expected to be arranged and when the system should switch between 128 kHz and 360 kHz behavior.

Resonant capacitor selection and dynamic switching in Clauses 4 and 5

The document gives detailed methods for selecting PRx and PTx resonant capacitors, including different values for BPP, default and nominal MPP, and high-power MPP. In high-power operation the PRx and PTx can switch capacitor values dynamically, with the switching logic driven by coupling estimation, inverter drive limits, and the need to preserve zero-voltage switching (ZVS). In practice, that means the design is not static: the resonant network is part of the control strategy.

Digital pings and coupling estimation in Clauses 8 and 9

Clause 8 defines digital pings at 128 kHz and 360 kHz, and Clause 9 defines KEstimation. Together they identify the receiver, estimate coupling, and feed the choice of power mode and capacitor tuning. In practice, these stages are the handshake that lets the system decide whether it should stay in low power, move to nominal power, or move toward high power.

GainMeasurement and end-to-end control in Clauses 11 and 12

Clause 11 uses GainMeasurement to help the pair find a workable operating point and set the initial VRECT target and maximum power level. Clause 12 then defines the end-to-end control loops, including the VRECT_target loop, the Ilim loop, gain linearization, and conversion from XCE to inverter drive. In practice, this is the closed-loop part of the standard: it is what keeps delivered power and rectified voltage under control once power transfer starts.

Over-voltage protection and load-dump behavior in Clause 14

Clause 14 treats over-voltage protection in the PRx as a shared responsibility between transmitter and receiver. It includes recovery behavior after load dump, fast-recovery guidance, and rules that keep the PTx from increasing drive during a disturbance. In practice, this clause matters when the load changes suddenly, because the system must bring VRECT back under control without making the event worse.

What terms does oSIST prEN IEC 63758-5-2:2026 define?

• PTx - Power Transmitter, the sending side that drives the magnetic field and controls inverter behavior.
• PRx - Power Receiver, the receiving side that rectifies the transferred power and regulates the load.
• DPM - Default Power Mode, the backward-compatible mode used when either product reports Qi version 2.1 or lower.
• LPM, NPM, HPM - Low, Nominal, and High Power Mode, the discrete operating bands used to match power level, voltage, and tuning strategy.
• CPM - Continuous Power Mode, a single-mode approach for systems with a fixed supply across the full power range.
• VRECT - The rectified voltage at the PRx, used as a key control target and a protection indicator.
• KEST - The coupling estimate derived during digital ping, used to choose mode and tuning settings.
• MODEXCAP - The capability packet that advertises supported power modes and their reference VRECT ranges.

Who uses oSIST prEN IEC 63758-5-2:2026?

oSIST prEN IEC 63758-5-2:2026 is used by engineers designing Qi wireless charging systems for flat-surface devices such as mobile phones and chargers operating at power levels up to 25 W. It is also used by power electronics and firmware teams that implement the transmitter inverter, receiver rectifier, control loops, and packet exchange.

In practice, the document is relevant to:

• PTx hardware and firmware designers
• PRx hardware, battery-charger, and control engineers
• Magnetics and resonant-network designers
• Test laboratories and compliance teams
• Quality managers checking mode support and protection behavior
• Buyers and integrators evaluating interoperability between products

Which standards are used with oSIST prEN IEC 63758-5-2:2026?

Section 1.1 places this part within the wider Qi Specification family. The most relevant companion books named there are:

• Qi Specification - Communications Protocol - packet formats and messaging behavior used by the digital exchanges.
• Qi Specification - MPP Communications Protocol - the MPP-specific negotiation and control messages.
• Qi Specification - MPP Magnetics Design - mechanical stack-up and magnetic design assumptions used by the tuning examples.
• Qi Specification - MPP Foreign Object Detection - the analogue ping and Q-measurement behavior used during object detection.
• Qi Specification - MPP Design Guidelines (Informative) - practical design examples and operating-point guidance.
• Qi Specification - Communications Physical Layer - the physical signaling basis for packet communication.
• Qi Specification - Power Delivery - the broader Qi power-delivery framework and BPP context.

What does the oSIST prEN IEC 63758-5-2:2026 document contain?

The document contains detailed system models, control flows, and design examples for MPP wireless power transfer. It includes figures, tables, and algorithms for mode selection, digital pings, KEstimation, resonant capacitor selection, gain measurement, and over-voltage recovery.

It also contains worked methods for checking operating conditions such as output impedance slope, load transients, and the effect of capacitor switching on rectified voltage. Several clauses are supported by state-machine style flows and parameter tables, so the reader can trace how the transmitter and receiver are expected to behave during handshakes, power transfer, and fault recovery.

SLOVENSKI STANDARD
01-november-2026
Specifikacija Qi - Različica 2.3 - 5-2.del: Mpp - Zagotavljanje napajanja (hitri
postopek)
Qi specification - Version 2.3 - Part 5-2: Mpp - Power delivery (Fast Track)
Ta slovenski standard je istoveten z: prEN IEC 63758-5-2:2026
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.

100/4544/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 63758-5-2 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 5-2: MPP - Power delivery (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–PowerDelivery
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 8
1.1 StructureoftheQi Specification 8
1.2 Scope 9
1.3 Compliance 9
1.4 References 9
1.5 Conventions 10
1.5.1 Notationofnumbers 10
1.5.2 Tolerances 10
1.5.3 Fieldsinadatapacket 10
1.5.4 Notationoftextstrings 11
1.5.5 Short-handnotationfordatapackets 11
2. PowerDelivery 12
2.1 PowerProfiles(BPP+MPP) 12
2.1.1 Specifications 12
2.1.2 Recommendations 13
2.1.3 SpecificationNotes 13
3. PowerModes 15
3.1 SystemModel 15
3.1.1 Reasonsforhavingmultiplepowermodes 15
3.1.2 Powermodesinthesystemmodel 15
3.1.3 Transitionamongpowermodes 19
3.1.4 AdapterVoltageTransitionswithPowerRemovalduringTransitions 21
3.2 Specifications 23
3.2.1 PowerModesSpec1 23
3.2.2 PowerModesSpec2 23
3.2.3 PowerModeSpec3(MPP25PTxonly) 23
3.2.4 PowerModesSpec4 23
3.2.5 PowerModesSpec5 23
3.2.6 PowerModesSpec6 23
3.2.7 PowerModesSpec7 23
3.2.8 PowerModesSpec8 23
3.2.9 SpecificationNotes 24
3.3 DesignConsiderations 25
3.3.1 PTxthatdoesnotrequirepowerremovalformodetransition 25
3.3.2 ProvidinginformationintheMODEXCAPdatapacket 27
4. PowerReceiverFunctionalBlockDiagram 28
4.1 SystemModel 28
4.1.1 SystemmodelPRxcircuittopology 28
4.1.2 SystemmodelPRxresonancetuninginBPPmode 29
4.1.3 SystemmodelresonancetuninginMPPmode(DefaultPowerMode,Low-Power
Mode,andNominalPowerMode) 30
4.1.4 SystemmodelresonancetuninginMPP(HighPowerMode) 35
4.1.5 CRXswitchalgorithm 35
4.1.6 PRxelectricalproperties 38
4.1.7 SystemmodelPRxVRECTsetting 38
5. PowerTransmitterFunctionalBlockDiagram 40
5.1 SystemModel 40
5.1.1 Definitionofinverterphaseθ 41
5.1.2 DefinitionofinverterdutycycleD 41
5.1.3 PTxresonantcapacitorselection 42
5.1.4 PTxcapacitorselectionalgorithm 42
5.1.5 PTxelectricalproperties 47
5.2 MitigatingfalseOVPtriggeringduringCTXswitching 49
5.2.1 TSGC001 49
5.2.2 REC/TSGC001 49
5.2.3 REC/RSGC001 49
5.2.4 REC/RSGC002 49
6. OperatingFrequency 50
6.1 SystemModel 50
6.2 Specifications 50
6.2.1 PTxFrequencySpec1 50
6.2.2 PTxFrequencySpec2 50
6.2.3 PTxFrequencySpec3 50
6.2.4 PRxFrequencySpec4 50
7. ObjectDetection 51
7.1 SystemModel 51
7.2 Specifications 51
7.2.1 PRxQDeflectionSpec1 51
8. DigitalPings128kHz/360kHz 52
8.1 SystemModel 52
8.1.1 NeedForDigitalPings128kHz/360kHz 52
8.1.2 PhasesinDigitalPings128kHz/360kHz 52
8.1.3 OverallFlow 53
8.1.4 IdentificationSequence 56
8.1.5 InverterConfigurations 58
8.2 Specifications 59
8.2.1 PTxDigitalPingSpecifications 59
8.2.2 PTxDigitalPingSpecifications-128kHzPingHB_Low 59
8.2.3 PTxDigitalPingSpecifications-360kHzPing 59
8.2.4 (Optional)PTxDigitalPingSpecifications–128kHzPingHPM 60
8.2.5 PTxDigitalPingRecommendations 61
8.2.6 PTxDigitalPingRecommendations-128kHzPingHB_High(informative) 62
8.2.7 PTxDigitalPingRecommendations-128kHzPingFB(informative) 63

8.2.8 PTxDigitalPingRecommendations-128_HPM 63
8.2.9 PTxDigitalPingRecommendations-360_LPM 64
8.2.10 PTxDigitalPingRecommendations-360_NPM 65
8.2.11 PTxDigitalPingRecommendations-360_HPM 65
8.2.12 PRxDigitalPingSpecifications 66
9. KEstimation 67
9.1 SystemModel 67
9.1.1 NeedForKEstimation 67
9.1.2 KESTCalculationFormula 68
9.1.3 Eco-systemScaling 69
9.1.4 CoefficientsforKESTConductedduringthe128_HPMDigitalPing 70
9.1.5 Errorstack-up 70
9.2 Specifications 71
9.2.1 PTxKESTSpec1 71
9.2.2 PTxKESTSpec2 71
9.2.3 PTxKESTSpec3 71
9.2.4 PTxKESTSpec4 71
9.2.5 PTxKESTSpec5 71
9.2.6 PTxKESTSpec6 71
9.2.7 PTxKESTSpec7 71
9.2.8 PTxKEST Spec8(MPP25PTxonly) 71
9.2.9 PTxKESTSpec9 72
9.2.10 PTxKESTRecommendation2 72
9.2.11 PTxKESTRecommendation3 72
9.2.12 PTxKESTRecommendation4 72
9.2.13 PTxKESTRecommendation5 72
9.2.14 PTxKESTRecommendation6 72
9.2.15 PRxKESTSpec1 73
9.2.16 PRxKESTSpec2 73
9.2.17 PRxKESTSpec3 73
9.2.18 PRxKESTSpec4 73
9.2.19 PRxKESTSpec5 73
9.2.20 PRxKEST Spec6(MPP25PRxonly) 73
10. OutputImpedanceandLoadTransients 74
10.1 SystemModel 74
10.1.1 SlopeoftheoutputImpedance 74
10.1.2 Worst-caseteststomeasuretheslopeoftheoutputimpedance 75
11. GainMeasurement 77
11.1 Background 77
11.2 SystemModel 77
11.2.1 TheoryofOperation 77
11.2.2 PRxballastcurrent 79
11.2.3 GainMeasurementFlowinDefaultPowerMode 80
11.2.4 GainMeasurementFlowinNominal-PowerandHigh-PowerModes 84

11.3 PTxSpecifications 90
11.3.1 PTxGainMeasurementSpec1 90
11.3.2 PTxGainMeasurementSpec2 90
11.3.3 PTxGainMeasurementSpec3 90
11.3.4 PTxGainMeasurementSpec4 90
11.4 PTxSpecificationNotes 90
11.4.1 EquivalentVinv 90
11.5 DesignConsiderations 90
11.5.1 DesignConsiderationsforotherPRxArchitectures 90
11.5.2 DetermineGC0andGC1 91
11.5.3 GainMeasurementintheContinuousPowerMode 92
12. PowerTransferControl 93
12.1 IntroandBackground(Informative) 93
12.2 SystemModel 93
12.2.1 BackgroundandAssumptions 93
12.2.2 Vrect_targetLoop(PRx+PTx) 96
12.2.3 IlimLoop(PRx) 104
12.2.4 Powerthrottling 106
12.3 End-to-EndControlSpecifications 107
12.3.1 Background 107
12.3.2 PTxSpecifications 107
12.3.3 PTxGainLinearizationSpec1 107
12.3.4 PRxSpecifications 110
12.3.5 PRxRecommendations 110
12.3.6 PRxSpecificationNotes 111
12.3.7 DesignConsiderations 112
13. MitigationofSideEffectsofCdatMPPFrequency 113
13.1 SystemModel 113
13.1.1 Non-monotonicVRECT/phaseresponseandoutputimpedanceatlightload 113
13.1.2 Receiverover-voltageprotection 116
13.2 Specifications 117
13.2.1 PTxOCPSpec1 117
14. Over-voltageProtectioninPRx 118
14.1 Introduction 118
14.2 OVPRecoveryFlow(Informative) 122
14.3 OVPRecoveryTimeAnalysis 124
14.4 MaxVRECTAnalysis 124
14.4.1 LoadDumpProcedure 125
14.5 ReducingVRECTOVPRisks(Informative) 126
14.6 Requirements 127
14.6.1 PTxOVPSpec1 127
14.6.2 PTxOVPFastRecoverySpec1 127

14.7 Recommendations 127
14.7.1 PTxOVPRecommendation1 127
14.7.2 PRxOVPRecommendation1 128
14.7.3 PRxOVPFastRecoveryRecommendation1 128
15. Cloak 129
16. Common-modeNoise 130
17. GGValueDefinitions 131
17.1 KESTcoefficients 131
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,MPPPowerDelivery(thisdocument)comprisesguidelinesandrequirementsforPowerReceiver
design,includingcircuitry,powerconsumption,operatingpowerlevels,powertransferefficiency,andstandbypower.
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.

2. PowerDelivery
Unlessotherwisestated,allcontentsinthisbookapplytopowerdeliveryinMPPmodeinsteadofBPPmode.
2.1 PowerProfiles(BPP+MPP)
2.1.1 Specifications
2.1.1.1 PowerDeliverySpec1
ThePTxshallprovideaBPPPRxwithatleast5Wofrectifiedpowerforr≤8mm,z≤3mm(Figure3).
NOTE:SeeSection2.1.3.1,Definitionofrandz forthedefinitionofrandz.
2.1.1.2 PowerDeliverySpec2
UnlessthePTxoperatesinMPPRestrictedMode,itshallhavethecapabilitytoprovideanMPPPRxwithatleast15W
ofrectifiedpowerinsidethe2x2cylinder(r≤2mm,z≤2mm)Figure2.
2.1.1.3 PowerDeliverySpec3
ThePTxshallprovideanMPPPRxwithatleast5Wofrectifiedpowerforr≤4mm,z≤3mm.
2.1.1.4 PowerDeliverySpec4
ThePTxshallprovideanMPPPRxinrestrictedmodeamaximumof6.5WreceivedpowerinMPPRestrictedmode.
ThisisbasedonBPPsystemspecification.
2.1.1.5 PowerDeliverySpec5( MPP25PTxOnly)
ThePTxshallprovideTPR#MPP4withatleast25Wofrectifiedpowerforr=0mm,z≤2mm.
2.1.1.6 PowerDeliverySpec6(MPP25 PTxOnly)
ThePTxthathasaVinlessthanorequalto20VshallhaveaVinv-VRECTRatioofatleast0.95withTPR#MPP4at
position(0,2).
NOTE:ThePTxdesignshouldensurethatthisrequirementissatisfiedusingitslowestCTXtoensurethehighestVRECT-Vinvratio.
PleaseseeSection3.2.9,SpecificationNotes forthedefinitionofsupporting25WandVinv-VRECTRatio.
2.1.1.7 PowerDeliverySpec7(MPP25PRxOnly)
ThePRxshallhaveaVinv-VRECTRatioofatleast0.95withTPT#MPP4atposition(0,2).
PleaseseeSection3.2.9,SpecificationNotes forthedefinitionofVinv-VRECTRatio.
2.1.1.8 PowerDeliverySpec8
WhenpairedwithaTPR,thePTxshalldeliveritsECAP[PotentialLoadPower]continuouslyforatleast150seconds
withoutthrottling.
2.1.2 Recommendations
2.1.2.1 PowerCapabilityReductionRecommendation1
InMPPmode;Forz>3mm&r>4mm,loadpowerdeliveryshouldgraduallydecreasefrom5Wasthedistanceand
heightfromthecentreincreases.
2.1.2.2 PowerCapabilityReductionRecommendation2(MPP25PTxOnly)
ThePTxmaygraduallydecreaseitsloadpowerdeliveryfromatleast25Wtoatleast15Wfor0 2.1.3 SpecificationNotes
2.1.3.1 Definitionofrandz
MPPdevicesarerequiredtoprovideguaranteedperformancewithrespecttoexternallyobservablefeaturesofthe
designsuchasdistancebetweenthecontactsurfaceofPTxtothecontactsurfaceofthePRx.Thus,inthespecified
powerdeliveryvolumebelowandthroughouttheMPPspecification,when"z"distanceisspecifieditindicatessurface-
to-surfaceseparationratherthan,forinstance,thecoil-to-coilseparation.
Forexample,Figure4showshowzgapbetweenaPTxandPRxisdefinedinthesystemmodel.Inthisexample,thePTx
andPRxhavethesamemechanicalstack-upasdiscussedintheMPPMagneticsDesignbook.
Theoriginr=0isdefinedasthelocationcorrespondingtomaximumcouplingwhenz=0.
Figure2- Forr=0mm,z≤2mm,a25WMPPPTxshallbeabletodeliveratleast25W.
Figure3-AnMPPPTxshallbeabletodeliveratleast5WtoanBPPsystemmodelPRxforr≤ 8mm,z≤3
mm
Figure4-Crosssectionviewofthesystemmodelindicatingthe"z"gap.

3. PowerModes
3.1 SystemModel
3.1.1 Reasonsforhavingmultiplepowermodes
Optimizingpowerdeliveryatdifferentpowerlevelscanleadtodifferentdesigndecisions.Inordertosupportpower
deliveryupto25W,thesystemmodelemploysdifferentpowermodesdependingonpowerlevels.Thisallowsthe
systemmodeltousethebesthardwareandalgorithmicstrategyforeachpowerlevel.
Apowermodeisasystemoptimizationforefficiencywithinaparticularpowerrange(seeTable3).Thefollowing
powermodesaredefined:
l
DefaultPowerMode(DPM):Themodeinwhichthesystemoperatesifeitherofthematedproductsreportv2.1
orlower.
l
LowPowerMode(LPM)/NominalPowerMode(NPM)/HighPowerMode(HPM):Thesemodesare
designedforusewithpowertransmittersthatoperatefromareconfigurablepowersupply(suchasaUSB-PD
adapter).
l
ContinuousPowerMode(CPM):Thismodeisdesignedforusewithpowertransmittersthatoperatefroma
fixedpowersupply(suchaswithinanautomotiveenvironment).
Categoricallyspeaking,thedesignconsiderationsbehinddifferentpowermodesinthesystemmodelare:
l
Voltagerange:Generally,lowerpowerlevelneedslowerinputvoltagetothePTxinverterandloweroutput
voltageatthePRxrectifier.Thishelpstocontroltheeffectivecurrentandimpedanceofthematedsystemand
containefficiencywithinadesiredrange.
l
Inthesystemmodel,theinputvoltagetothePTxinverteriscontrolledbyaboostconverter(SeeFigure
7).Therefore,alowerinputvoltagetothePTxinverterleadstoalowerinputvoltagetotheboost
converter(i.e.,adaptervoltage).
l
EMI:Therearetwoscenarioswheretherearehigherradiationrisks:
l
WhenthePTxinverterisinphaseorduty-cyclecontrolmode(seeSection6.1,SystemModel),the
switchingwaveformshavemorehigh-harmonicdistortions.Thisusuallyhappensatlowpowerrange.
l
WhenthePTxinverterlosesZVS(zero-voltageswitching)operation,theinvertermayhavesharp
switches.EnsuringZVSgenerallyrequiresinductiveload,andsinceeffectiveloadchangeswithpower
level,thesystemmodelneedsdifferentcapacitortuningstrategies.
l
Controlresolutionandrange:Thecircuitgain(seeSection12.2.2.3,PTxControl)varieswithpower,resultingin
controlinstabilityorinsufficientdynamicrange,ifnotcontained.Thesystemmodelusesdifferentresonant
capacitors,targetVRECTvoltages,andadaptervoltagestounifythegainasmuchaspossibleatdifferentpower
levels.
Withthesedesignconsiderations,Section3.1.2,Powermodesinthesystemmodel explainsthepowermodesemployedin
thesystemmodel.
3.1.2 Powermodesinthesystemmodel
Thesystemmodeldividespowerlevelsintolow,medium,andhigh,thusresultinginthreepowermodes:lowpower
mode,nominalmode,andhigh-powermode.

Additionally,thesystemmodelutilizesa"DefaultPowerMode".IfthesystemmodelPTxandPRxagreetobeinthis
mode,theyoperateinawaythatisbackwardscompatiblewithproductscertifiedtopreviousversionsoftheQi
Specification.
Thefollowingtablesummarizesthepowermodesanddesignparametersassociatedwitheachmode.Thesedesign
choicesareexplainedindetailintheirrespectivesections,asannotatedinthetable.SeeSection3.3,Design
Considerations forexamplesofothersystems.
Table3-PowerModesinthesystemmodel
Low
DefaultPower NominalPower HighPower ContinuousPower
Power
Optimized N/A Upto5 4.5W-20W 12-25W Upto25W
Power W
Level
(approx.)
(seeFigure
5)
Adapter 9V 5V 9V 15V ≥9V
voltage
(seeSection
3.1.4,
Adapter
Voltage
Transitions
withPower
Removal
during
Transitions
)
l
CTXtuning Initializedto: 101nFwhen
(360kHz)
l
101nFwhen 458nFwhen
l
(seeSection
l
5.1.3,PTx 68nFwhen
68nFwhen
l
resonant
capacitor l
134nFwhen
selection)
Dynamicallycontrolled
afterinitialization
Low
DefaultPower NominalPower HighPower ContinuousPower
Power
CRXtuning Fixedat710nF  Initializedto710nF,
(360kHz) thendynamically
l
Initializedto710nF
(seeSection
controlledbasedon
l
Dynamicallycontrolledbasedonpower
4.1.3,
powerlevel,after
level,afterinitialization
System initialization
model
resonance
tuningin
MPPmode
(Default
Power
Mode,Low-
Power
Mode,and
Nominal
Power
Mode) and
Section
4.1.4,
System
model
resonance
tuningin
MPP(High
Power
Mode))
l l
Vinrange 11V-18V 6.5V- 10V–18V 16V-20V 6.5V-23V
(seeSection
(low-k 18V (low-k
12,Power
mode) mode)
Transfer
l l
MPT#1:11 10V–20V
Control)
V-19V (otherwise)
(otherwise)
l
MPT#2:11
V-25V
θrange 0°-50° 0° 0°-50° 0°-50° 0°
(seeSection
12,Power
Transfer
Control)
VRECT Switchbetween 12.5V Dynamic,between 18V Dynamic,between
target 12Vand14V 12.5Vand18V 12.5Vand19V
(seeSection
withhysteresis
4.1.7,
System
modelPRx
VRECT
setting)
NOTE:Somedesignparametersinthistableare“approximations”,becauseofhysteresisorothercornerconditions.Pleasereferto
eachspecificsectionfortheexactvaluesandconditions.
NOTE:Someimplementationsmayonlyuseasinglepowermode,e.g.continuouspowermode.SeeSection3.3,Design
Considerations forfurtherdetails.

3.1.3 Transitionamongpowermodes
PRxisthesidewhodetermineswhichpowermodethewirelesspowertransfershouldbeunder.Themainreasonis
becausePRxknowspowerrequirementsasithasdirectaccesstotheloadpower.
Figure5describeshowthesystem-modelPRxtransitsamongdifferentpowermodes.Specifically:
l ThePRxstartswithnominalpowermodeorhigh-powermodedependingontheestimatedcoupling (See
Section9,KEstimation);
l
AfterSetPr_max(Section11,GainMeasurement),thePRxshiftstonominalmodeiftheestimatedG3istoosmall;
l
Duringpowertransfer,transitionsbetweenmodesarebasedonobservedloadpower.Therearetwotypesof
transitions:
l
“fast”transitionsareusedtotriggerpowermodetransitionsbasedonfastPRECTchanges(t_high_fastand
t_low_fastinTable4);
l
“slow”transitionsareusedtotriggerpowermodetransitionsbasedongradualPRECTchanges(t_high_
slowandt_low_slowinTable4)
l
Onceinnominal-powermode,thesystemmodelPRxdoesnottransittohigh-powermodeuntilpoweris
removedwhenthePRxsendseitheranEPTorCLOAK datapacket.
TheparametervaluesusedinFigure5arespecifiedinTable4.
Figure5-TransitionbetweenPowerModes

Table4- TransitionbetweenPowerModes(Parameters)
Symbol Value
Kest_th_hpp 0.657
G_th_hpp 0.98
P_th_high_fast 12W
t_high_fast 3seconds
P_th_low_fast 2.5W
t_low_fast 4seconds
P_th_low_slow 4W
t_low_slow 40seconds
P_th_high_slow 4.5W
t_high_slow 40seconds
current_limit_mode ABooleanflagindicatingthattheloadcurrentmeetstheloadcurrentlimit(seeSection
12.2.3.1,LoadCurrentControl)
InpracticalPRxdesigns,Figure5isdesignedforthescenariowheretheVRECTofPRxisnottiedtobatteryvoltage(for
example,oneswithabuckconverter).ForthePRxwhoseVRECTistiedtobatteryvoltage,pleaseseeanexamplein4.

3.1.4 AdapterVoltageTransitionswithPowerRemovalduringTransitions
PowermodesprovideameansforPTxtoelegantlyswitchamongdifferentpotentialadaptorvoltages(Vadapter).Each
powermodecouldcorrespondtoaVadaptersetting,orasetthereof.Duringpowermodetransitions,PTxcanelectto
rampdownpowertoensuresafeadaptervoltagetransition.
Figure6showsanabstractmodelofaPTxadapterconfigurationthatsupportstwoadaptervoltages,VAandVB.VAand
VBbelongtodifferentpowermodes,andswitchingbetweenthemrequirespowerinterruption.
Figure6-AnabstractmodelofaPTxadapterconfigurationthatrequirespowerinterruptionduringpower
modetransition.
Thesystem-modelPTxisanexampleofsuchconfiguration.Itsupportsthreediscreteadaptervoltages:5V,9Vand15
V.ApracticalexampleofsuchconfigurationisanUSB-CPDcharger.BetweenVadapterandVin,thereisaboost
converter(Figure7).Table5showsthesupportedvoltageofthesystemmodelPTx.
Figure7-SystemmodelPTxinputDC/DCconverter
Table5-VadapterandsupportedVinofthesystem-modelPTx.
Vadapter MinimumSupportedVin MaximumSupportedVin
5V 6.5V 20V
9V 10V 20V
15V 16V 20V
Figure8showsanexampleofhowthesystem-modelPTxperformsadaptervoltagetransitionbeforerampingupto
high-powermode.Inthisexample,weassumethepoweradapter,PTxandPRxallmeetthepowercapacitytooperatea
high-powermode.Thesystem-modelPTx/PRxpairgothroughthefollowingsequence:
l
Vadapterstartsat5V;
l
PTxstartsobjectdetectionanddetectsthepresenceofPRx(seetheFODchapter);
l
PTxnegotiates9V/3Awiththeadapterandobtainsconfirmation;
l
PTxstarts128kHzdigitalping(seeSection8,DigitalPings128kHz/360kHz);
l
Inthenegotiationphase,PRxrequestshigh-powermodeandPTxconfirmsit;

l
SincePTxknowsPRxrequestsforhigh-powermode,PTxnegotiates15Vwiththeadapterandrestartthe
inverterfor360kHzoperation;
l
PTxstarts360kHzdigitalping(seeSection8,DigitalPings128kHz/360kHz);
l
Inthenegotiationphase,PRxandPTxre-confirmhigh-powermode;
l
ThePTx/PRxpairperformG3measurement(seeSection11.2.3,GainMeasurementFlowinDefaultPowerMode),
thenuseXCEpacketandVRECTtargettoregulatepowerto25W(seeSection12,PowerTransferControl).
RefertotheMPPCommunicationsProtocolbookformoredetails.
Toreducethepowerramp-uptime,theexpectedpowermodemaybeselectedduringthe128kHznegotiationphase.
SincethePTxneedstorebootitsinverterbeforethe360kHzdigitalping,itusesthesameopportunitytonegotiatewith
theadaptertotransittothedesiredvoltageaswell.Bydoingso,thesystem-modelPTxminimizesthenumberof
unnecessarypowerdisturbancetoPRx.
Figure8-Exampleflowforsystem-modelPTxwithaUSB-CPDadaptertoperformadaptervoltagetransition
duringramp-uptohigh-powermode.

3.2 Specifications
3.2.1 PowerModesSpec1
Foreachsupportedpowermode,thePTxshallbeabletoprovideTPR#MPP4withthedeclaredpotentialpowerinits
advertisedMODEXCAPdatapacketwithinr=0mm.0mm≤z≤2mm.
3.2.2 PowerModesSpec2
ThePTxshalladvertiseapotentialpowerofatleast15WforatleastoneofthepowermodesitlistsintheMODEXCAP
datapacket.
3.2.3 PowerModeSpec3(MPP25PTxonly)
ThePTxshalladvertiseapotentialpowerofatleast25WforatleastoneofthepowermodesitlistsintheMODEXCAP
datapacket.
3.2.4 PowerModesSpec4
ForPTxsusingdiscretepowermodes,thePTxshalladvertisepotentialloadpowersuchthat"HPMPotentialLoad
Power">"NPMPotentialLoadPower">"LPMPotentialLoadPower."
3.2.5 PowerModesSpec5
ThePTxshallsupportallthepowermodesbelowthehighestadvertiseddiscretepowermode(LPM,NPM,HPM).
3.2.6 PowerModesSpec6
ForPTx'susingdiscretepowermodes,thePTxshalladvertiseoverlapping"VoltageRef0"and"VoltageRef1"inthe
MODEXCAPdatapacketforeachsupportedpowermodesuchthat:
l
LPMVoltageRef1≥NPMVoltageRef0
l
NPMVoltageRef1≥HPMVoltageRef0
NOTE:IfVoltageRef0andVoltageRef1aresetto0thenthatcorrespondingpowermodeisnotsupported
3.2.7 PowerModesSpec7
APTxthatsupportsCPMshallnotsupportanyofthediscretepowermodes(LPM,NPM,HPM).
3.2.8 PowerModesSpec8
PTxshallsupportLPMwithapotentialloadpowerofnomorethan10W.

3.2.9 SpecificationNotes
1. RelaxedVolume:ComparedwithPowerprofilespecifications(Section2.1.1,Specifications),Powermode
specificationsusearelaxedvolumeforguaranteedpower:insteadofthe2x2cylinder,thepowermode
specificationsarerequiredforalinesegmentof0mm≤z≤2mmonther=0mmaxis,forthereasonsbelow:
l
High-powermodedeliveryisanenhanceduserexperience,butahigherpowerlevelimposeschallenges
especiallywhenthecouplingislow.Therefore,itmakessensetoguaranteethisuserexperiencewitha
smallerLQKspacewithstrongcouplings.
l
zheightismoreimportantthanrtoallowforpotentialaccessoriesinbetween.
2. DefinitionofVinv-VRECTRatio:Vinv-VRECTratioofaPTx-PRxpairisdefinedastheratiobetweenVRECTand
Vinv,whenthePRxoperatesataconditionwith
Asdemonstratedin Figure9,thereisastrongcorrelationbetweenVinv-VRECTandachievablePRECT,especially
around25W.Therefore,theVinv-VRECTratioisadependablecharacteristicoftheelectricalandmagnetic
propertiesofthePTxorPRxdevicethatcanbeusedtopredictthepowercapacityofthesaiddevice.
Figure9-StrongCorrelationbetweenPRECTandVinv-VRECTRatio
Monte-Carlosimulationswererunacrossthemagneticboundaryandkeycomponenttolerances(e.g.,CTXandCRX).The
Y-axisisthemaximumpossiblePRECTwhenPTxreachesitsmaximuminverterdriveandifthereisnomaximum
powerlimit.TheX-axisistheobservedVinv-VRECTratioinsimulation.

3.3 DesignConsiderations
3.3.1 PTxthatdoesnotrequirepowerremovalformodetransition
NotallPTxdeviceshavediscreteadaptervoltagesandVinrangesthatrequirepowerinterruptionduringpowermode
transitions.Forexample,aPTxmountedinsideanautomobilemayhaveasinglecontinuousVinrangethatcansupport
allthewayupto25W.RefertotheMPP DesignGuidelines(Informative)bookforsomeexamples.
Figure10-Examplesofpossibleadapterandconvertercombinationsthatmaysupportasingle,continuous
Vinrange
ThereareafewdesignconsiderationsforthesePTxdevices:
l
ThePTxmanufacturercandecidetosupportasinglemode,e.g.,continuouspowermode,forthewholepower
rangeupto25W.ItcouldelecttoadvocatetoPRxthatneitherlow-powermodenornominal-powermodeis
supported.
l
ThePTxmanufacturercanalternativelydecidetosupportmultiplemodes,butwithnopowerremovalduring
powermodetransition.
l
ThePTxdoesnothavetofollowthesystem-modelVinranges(Table3).Forexample,inthesystem-modelPTx,
thelowerlimitofVininhigh-powermodeis16V(seeTable3.).ThiscouldposelimitationstoPRxdevicesthat
usesswitched-capconverters,whichhaveamuchlargerdynamicrangeofVRECTthanthesystemmodelPRx
(Section4,PowerReceiverFunctionalBlockDiagram).ThePTxcanchoosetosupportalowerlimit,forexample,
12.5V.
DependingonthecharacteristicsofthePTxandPRx,manufacturersshouldreachtheirowndecisionsonwhatpower
mode(s)tosupport,andtheircorrespondingoperatingranges.Table6andTable7providetwoexamples.
Inthefirstexample,wehave:
1. aPTxdesignthatissuppliedbyacarbattery,usesabuck-boostconverter,andsupportsonlyonepowermode,
and
2. aPRxdesignthatusesswitched-capconverter
Table6-PowerModesExample1
ContinuousPowerMode
OptimizedPowerLevel N/A
AdapterVoltage 12.6V-14.4V
CTXtuning dynamicallyswitched
CRXtuning Initializeto710nF(anddynamicallycontrolwhennecessary)
Vinrange 0-23V
θrange 0°
VRECTtarget RefertotheMPP DesignGuidelines(Informative)book.
Inthisexample,wehave:
1. aPTxdesignthatissuppliedbyacarbattery,usesabuck-boostconverter,andsupportstwopowermodeswith
nopowerremovalatpowermodetransition,and
2. aPRxdesignthatusesswitched-capconverter
Table7-PowerModesExample2
NominalPowerMode HighPowerMode
OptimizedPowerLevel 0-15W 15W-25W
AdapterVoltage 12.6V-14.4V
CTXtuning Fixed. Dynamicallyswitched
l
101nFwhen
l
68nFwhen
CRXtuning Dynamicallyswitched Dynamicallyswitched
Vinrange 0-23V 12.5V-23V
θrange 0°
VRECTtarget RefertotheMPP DesignGuidelines(Informative)book.

3.3.2 ProvidinginformationintheMODEXCAPdatapacket
Duringnegotiation,thePTxprovidesareferenceVRECTrangeassociatedwitheachpowermode,throughMODEXCAP
packet.ThereferenceVRECTrange,say,(Vrect_ptx_min,Vrect_ptx_max),istheVRECTachievableatTPR#MPP4while
deliveringthepowerspecifiedbytherelevantPowerModePotentialLoadPower.ThePRxcanusethisinformationto
approximatelyconvertthisreferenceVRECTtoitsownVRECTifpairedwiththePTx,andselectwhetheritshouldstart
withNPMorHPMmode.Belowisanexampleofsuchconversionmethods:
l
ThePTxpairsitselfwithaTPRandmeasuresitsreferenceVRECTrangeunderthesameloadcurrent:(Vrect_prx_
min,Vrect_prx_max)
l
TheTPT/TPRpairprovidesa"golden"referenceVRECTrangewhentheyarepaired:(Vrect_tp_min,Vrect_tp_
max)
l
ThePRxcanapproximateitsVRECTrangewiththefixedloadcurrentwhenpairedwithaPTxas:(Vrect_ptx_min
*Vrect_prx_min/Vrect_tp_min,Vrect_ptx_max*Vrect_prx_max/Vrect_tp_max)
Duringpowertransfer,sometimesthePTxmaydesireamodechange,eithersuggestiveorassertive.
l
Suggestion:UsetheMSN datapacket
l
Assertion:Forexample,whenpowerdropsinHigh-PowerMode,thePTxcouldenterthephase-controlregion
andtriggerZVS.IfthePTxdecidesthatthisisundesirableorunacceptable,thePTxcanforcePRxtochangethe
powermode,byupdatingitssupportedpowermodeinfo,i.e.,thePTxcouldremoveHPMfromitssupported
powermodes(forcingthePRxtochangepowermode).
l
Assertion:Removethepowersignalimmediatelyandre-ping.
PleaserefertotheMPPCommunicationsProtocolforfurtherdetails.

4. PowerReceiverFunctionalBlockDiagram
4.1 SystemModel
4.1.1 SystemmodelPRxcircuittopology
ThesystemmodelPRxcircuittopologyispresentedinFigure11andinTable8.
DuringdigitalpingandBPPmodeS1isopen.AftertheMPPhandshakethePTxwillturnoffandswitchto360kHz.
WhenthePRxdetects360kHzitwillturnonS1toenterMPPpowerdeliverymode.
ThePRxcomprisesthefollowing:
l
SeriesimpedancetuningnetworkforBPPandMPP
l
Parallelresonantfordetection
l
Idealfull-bridgerectifier
Additionally,thesystemmodelPRxassumesthattheloadhasapowerconverter(e.g.Buckconverter)forconverting
betweentheoptimalVRECTregulationvoltage,tothe4Vbatteryvoltage.Ithasthefollowingproperties:
l
Theinputcurrentlimit(Ilim)iscontrollableandusedtocontrolthemaximumrectifiedpower(seeSection12.2.3,
IlimLoop(PRx)).
l
TheoutputvoltageisregulatedtobatteryvoltagewhenVRECT>4V
Figure11-SystemmodelPRxcircuittopology(withBPPandMPPcompatibility).

Table8-PRxseriestuningconfiguration.
Powertransfer
S1 Transmitterfrequency
mode
open 128kHz 128kHzdigitalping
open 128kHz BPPpowertransfer
closed 360kHz MPP360kHzdigitalping
closed/open 360kHz MPP powerdeliverywhereS1is
dynamicallycontrolled
closed 360kHz MPP DefaultPowerMode
4.1.2 SystemmodelPRxresonancetuninginBPPmode
FollowingthesystemmodelmechanicaldesignintheMPPMagneticsDesignbook,andtheDualResonantCircuitsection
inthePowerDeliverybook, wecantunetheBPPmodecapacitors toseriesresonantfrequency:
PRxcoilinductance,matedwithPTxCoilSystemModelinQifrequencyrange:
=14.6μH
So,theseriesresonantcapacitor is:
=174nF
Inpracticaldesigns,therecommendedtolerancesof and areboth±5%.
Parallelresonantfrequency
PRxcoilinductancewithoutPTxferritepresent(Freeairinductance) :
=9.17μH
So
=2.7nF
Inpracticaldesigns,therecommendedtoleranceof is±0.6μH,and is±10%.

4.1.3 SystemmodelresonancetuninginMPPmode(DefaultPowerMode,Low-PowerMode,and
NominalPowerMode)
FollowingthesystemmodelmechanicaldesignintheMPPMagneticsDesignbook,weselectthePRxresonantcapacitor
tobethefollowingvaluebasedonthematedinductance:
= + =710nF
Notethatthe valueat360kHzMPPmodeishigherthan usedfor128kHzBPPmode(174nF,seeSection4.1.2,
SystemmodelPRxresonancetuninginBPPmode),despitethattheMPPfrequencyishigher.InBPPmode, ischosen
totunethePRxcoiltobeclosetotheresonantpoint;thismethodworksbyminimizingthePRxreactance,andworks
wellwhenthecouplingisrelativelylow.Whenthecouplingishigh,asinthecasewith360kHzMPPmode, needsto
bechosenwith consideringPTxandPRxasawholesystem,insteadofjustPRxinisolation.Thefollowing
subsectionsexplainthemethodologyofhow and valuesareselectedforthesystemmodelinMPPmode.
4.1.3.1 Ruleofthumb
Theruleofthumbinselectingresonantcapacitorat360kHzinthesystemmodelistohaveitsequivalentcapacitance,
includingreflected ,toresonantwiththeleakageinductanceonthePTxside.ConsidertheCantileverequivalent
circuitinFigure12:
Figure12- CantileverEquivalentCircuit.
and shouldbeselectedsothatthe currentbranch(dottedblue)isclosetoresonance.Thetotalequivalent
capacitanceis
Wehavetwodifferentresonantfrequencies:
1. PTxresonantfrequency:
2. Powertransferresonantfrequency:
Andcapacitorscanbechosencorrespondinglytotunetheresonancepoints.
Sincewearetuningtheequivalentcapacitancewithregardtotheleakageinductance,the valuechoseninMPPmode
ishigherthan inBPPmode:theleakageinductanceismuchlowerthantheself-inductance,especiallyathigh
couplinglocations.
Usingtheresonanceequationsonlygiveaninitialsetof and values.Thefinalvaluesusedinthesystemmodelare
chosenwithmuchmorecarefuldesignconsiderations.PleaseseeSection4.1.3.2,Selectionofresonantcapacitors.

4.1.3.2 Selectionofresonantcapacitors
Inthesystemmodel,theresonantcapacitorsareselectedtomeetthefollowingprimarydesigngoals:
l
15Wpowerdeliverywithin2x2cylinder;
l
ZVS(zerovoltageswitching)isguaranteedforlowEMI;
l
Optimizationforefficiency.
Thissectiongivesasummaryofthedesignexerciseleadingtotheselectionofthecapacitorsinthesystemmodel.
Essentially,startingfromthecapacitorvaluesindicatedinSection4.1.3.1,Ruleofthumb,therearethreesteps:
1. FHA(firstharmonicapproximation)toselectinitialcapacitorvalues,
2. Time-domainsweepsofworst-caseoperatingconditionstooptimizethevalues,
3. Practicaldesignconsiderationstofinalizethevalues.
4.1.3.3 FHAanalysis:selectinginitialvaluesofC
t
Thefirststep(FHAanalysis)canbedoneanalytically.Theequivalenttotalinputimpedanceatthetransmittersidecan
bewrittenasin4.
Equation:1
where
l , , , arethematedPTxinductance,PRxinductance,PTxresistanceandPRxresistance,respectively
(seetheGlossarybook )
l isthePRxparallelcapacitor(seeFigure11)
l
istotalmutualimpedance.Withinductivecoupling andresistancecoupling ,
l
istheequivalentACresistanceoftheload.InFHA,assumingtherectifierisincontinuousconductionmode,it
canbeestimatedas
BasedonEquation:1,thesystemgaincanbederived:
Equation:2
Avalidsetofresonantcapacitorvaluesshouldmeetthefollowingcriteriaforallpossiblemagneticparameterswithin
the2x2cylinder:
1. Thephaseof (Equation:1)ishigherthan20degreestoensureZVS
2. Toreachthedesired (14V,seeFigure19)at15W,thegain (Equation:2)shouldbebigenoughsuch
thattheneeded that'slessthanthemaximum(Table13)
Ontopofmeeting1and2,anoptimizedsetofcapacitorvaluesshouldyieldashighefficiencyaspossible.
Theworst-casescenarioofcriteria1and2maybeachievedatdifferentoperatingconditions.Forexample,withall
otherparametersequal,theworst-casescenarioofcriterion1isreachedatmaximum  whiletheworst-caseofcriterion
2isreachedatminimum .
Asweepofalloperatingconditionsisthendonetodecidethebestchoiceof and :
l Tuning toPRxcoilresonanceleadstosuboptimal values.Amuchhigher isneeded.Thisisevidentby
lookingattheefficiency(Figure13),Zin(Figure14)andgain(Figure15).Thisconfirmsthefirstprinciples
showninSection4.1.3.1,Ruleofthumb.
l Inthesystemmodel,asingleselectionof isn'tpossibletomeetbothcriteria,sotwodifferent valuesare
useddependingontherangeof .
Figure13showsthatefficiencyislowwhen <300nF(systemiscapacitive).
Figure13- EfficiencyvsCRX:sweepofCRXatthemaximumcouplingpositioninthesystemmodel
Figure14showsthat,with =60nF,thesystemimpedanceiscapacitive,whichisundesirable.

Figure14-BodeplotofZin(s)atmaximumcouplinglocationwithtwodifferentCRXvalues.
Figure15showsthat =710nFhas~1.4dBhighergainthan =60nF.
Figure15-BodeplotofG(s)atmaximumcouplinglocationwithtwodifferentCRXvalues.
4.1.3.4 Time-domainsweep
Oncetherangesofvaluesof and capacitancesaredownselected,time-domainsimulationsareruntofine-tune
thevalues.Time-domainsimulationshelptocaptureharmoniceffectsthatareneglectedinFHA.Thethirdharmonic
frequencyisparticularlyimpactfulsinceitresonateswith ,whichisfurtherexplainedinSection13,MitigationofSide
EffectsofCdatMPPFrequency .
4.1.3.5 Otherdesignconsiderations
Todeterminethefinalvaluesofthesystem-model and capacitance,thereareafewotherdesignconsiderations:
l
With >> ,thetoleranceon isreduced.Theisverybeneficial,asduetospacelimitations,PRxusuallyhas
touselowerqualityX5Rcapacitors(comparedtoC0GcapacitorsinthePTx).

l
Withhigher valueandlower value,ASKmodulationdepthon isincreased.
l Capacitorvaluesareroundedtothecloseststandardvalues.Forexample,thefollowingtableshowshow
valuesarerounded:
Table9-Powertransfertoresonancecapacitors
range Optimalequivalent Finalvalue
≥0.81 100nF 101nF(68nF+33nF)
<0.81 65nF 68nF
4.1.4 SystemmodelresonancetuninginMPP(HighPowerMode)
Inputvoltagedynamicrangeisanewchallenge,inadditiontotheonesdescribedinSection4.1.3,Systemmodel
resonancetuninginMPPmode(DefaultPowerMode,Low-PowerMode,andNominalPowerMode),whenextendingthe
powerlevelofthesystemmodeltobebeyond15W.Inhigh-powermode,thesystemmodelusesa15Vadapterinput
voltage,whichsignificantlyshrinkstheinputvoltagerange,especiallythelowerbound(16V).Thesystemmodelneeds
tocarefullyconstrain (seeEquation:2)sothattheVinvneededtoreachthedesiredVRECTiswithinthe
narrowrangeof16V-20V.
Additionally,thesystemmodelneedstochoosethecapacitorthatguaranteesZVSoperationandyieldsthebest
efficiency.
ByanalyzingG(s)andZin(s),wecanseethefollowinggeneraltrendwithinthesystemmodel’soperatingcondition:
l
AhigherCTXleadsto:
l
smallerG(s)amplitude,thusneedingahigherVinvtoregulatepower
l
moreinductiveZin(s),thuslessZVSrisk
l
AhigherCRXleadsto:
l
smallerG(s)amplitude,thusneedingahigherVinvtoregulatepower
l
moreinductiveZin(s),thuslessZVSrisk
Atthesametime,alowerpowerlevelrunshigherrisksofexhaustinglowerboundofVinvandlosingZVS,thusahigher
CTXandCRXvaluesaredesirable.Therefore,thestrategyofcapacitortuninginMPPhigh-powermodeissummarized
as:
StartingwiththehighestCTXandCRXvalue,dynamicallyswitchtothenextsmallervaluewheneverthecurrentvalue
cannotmeetthepowerdeliverygoal.
ThisstrategyexpandstotheCTXswitchingalgorithminSection5.1.4,PTxcapacitorselectionalgorithm andCRX
switchingalgorithminSection4.1.5,CRXswitchalgorithm.Twoadditionaldesignconsiderationsalsogointothesetwo
algorithms:
l
SwitchingCTXisprioritizedoverswitchingCRX,i.e.,CRXisswitchedonlyifallCTXvalueshavebeenexhausted.
l
AnadditionalCTXvalue(134nF)isaddedtoCTXvaluechoices.Otherwise,thegapbetween458nFand101nF
istoobigtoguaranteeoperationsacrossallpowerlevels.
4.1.5 CRXswitchalgorithm
Asdiscussedabove,innominalpowermodeandhighpowermode,thesystemmodelPRxswitchesCRXdynamically
duringpowertransfer.Specifically,therearetwoCRXvaluestoselectfrom:
l
The“low”value(174nF):requireslowerVinvtodeliverhigherpowerbutwithmoreZVSrisk
l
The“high”value(710nF):haslessZVSriskbutrequireshigherVinvtodeliverpower
Figure16showsthehigh-levelstatediagram.Therearetwokeysubroutines:
l
CheckSwitchToLow(Figure17):duringthestatewhereCRXholdsthehighvalue,thesystemmodelPRx
constantlychecksifitshouldswitchtothelowvalue.
l
CheckSwitchToHigh(Figure18):similarlythesystemmodelPRxchecksifitshouldswitchtothehighvalueifit
holdsthelowvalue.
BothsubroutinesaretriggereduponsendingtheMPLApacket.

Figure16-CRXSwitchingHigh-LevelStateMachine
TheCheckSwitchToLowsubroutineessentiallyperformsthefollowingsequentially,ashighlightedinFigure17:
l
CheckifCRXswitchisallowed:thesystemmodelallowsCRXswitchingifeitherthefollowinghappens:
1. KEST(Section9,KEstimation)islowsothesystemmodelPRxexpectsahighCRXisn’tsufficientto
deliverhighpower;
2. Vinvcontinuouslymaxesout,whichindicatesweneedalowerCRXvalue.ThePRxdetectswhetherVinv
hasmaxedoutviaPTx’sresponsetoXCEpacket.ThisguaranteesthatCTXcapacitorswitchingis
prioritizedoverCRXcapacitorswitching(asdiscussedinSection4.1.4,Systemmodelresonancetuningin
MPP(HighPowerMode)).
l
Switchonlyifthedesiredpowerishigh:thelowCRXvalueisneededonlywhenthesystemmodelPRxdesiresa
highpowerlevel(seeFigure17fortheexactthreshold),therefore,thesystemmodelPRxdecidestoswitchCRX
tolowonlyifthePRECTlevelishigh
l
Rampdownpowerbeforeswitching:toconductCRXswitchingwithoutriskingOVP,thesystemPRxrampsdown
powerbytemporarilylimitingmaxPrectto12W,andwaitinguntilpowerrampsdownbeforeactually
performingtheswitch.NotethatthePRxloaddoesn’tdirectlydroptotheloweredmaxPrectinonestep,it
followstheloaddumplimits(seeSection12.3.5,PRxRecommendations)andperformsmultiplesteps,soittakes
multipleMPLApacketsforthePRxtowaitforsufficientlylowpowertoswitchCRX.

Figure17- Subroutine:CheckIfCRXCanSwitchtothe
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