prEN IEC 63758-10:2026

• 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 63758-10:2026 - Qi Specification - Version 2.3 - Part 10: Communications physical layer (Fast Track)

prEN IEC 63758-10:2026 is a CLC draft standard in the Qi Specification series. It specifies the communications physical layer for Qi wireless power transfer, including how bits, bytes and packets are encoded over the Power Signal. The document is for designers and test teams working on Power Receiver and Power Transmitter equipment that must communicate reliably in Qi systems.

What does prEN IEC 63758-10:2026 specify?

prEN IEC 63758-10:2026 defines the low-level physical layer and data link layer formats for Qi communications. It covers both directions of communication between the Power Receiver and the Power Transmitter, and it gives the rules for load modulation and frequency-shift keying.

The document is organized into three main clauses:

• Clause 1, General - structure, scope, compliance, references and conventions
• Clause 2, Load Modulation - Power Receiver to Power Transmitter communications
• Clause 3, Frequency-shift keying - Power Transmitter to Power Receiver communications and Response Pattern handling

In practice, this means the standard tells implementers how Qi devices put information onto the power link, how the other side detects it, and how data packets are formed and checked.

What are the key requirements of prEN IEC 63758-10:2026?

prEN IEC 63758-10:2026 sets out the encoding, timing and packet rules that make Qi communications interoperable. The most important points are below.

Clause 1 - compliance and notation

The Qi Specification treats provisions as mandatory unless they are explicitly marked as recommended, optional, note, example or informative. Clause 1 also sets the meaning of shall, should, may and can. For a project team, this matters because it separates binding requirements from guidance.

Clause 1 also fixes the document’s notation rules: numeric values are exact unless stated otherwise, packet fields use big-endian order, text strings use printable ASCII with NUL padding, and packet shorthand uses a mnemonic plus modifier. That helps designers read packet definitions consistently and implement fields without ambiguity.

Clause 2 - Power Receiver to Power Transmitter load modulation

prEN IEC 63758-10:2026 requires the Power Receiver to use backscatter modulation by changing the power it draws from the Power Signal. The Power Transmitter detects this as amplitude modulation on the Primary Cell current and/or voltage. In practice, this is the return channel, so the receiver has to shape its load in a way the transmitter can sense.

The modulation scheme uses two stable states, HI and LO, with transition and stability limits given in Clause 2.1. The document also gives amplitude conditions for proper alignment with type A10 or MP-A1 Power Transmitters and appropriate loads. This matters because the sender must produce a detectable change even when the receiver is aligned and loaded as expected.

Clause 2 encodes data bits with differential bi-phase timing. A ONE uses two transitions, while a ZERO uses one transition. The receiver aligns each bit to an internal clock with a specified frequency tolerance. This gives the transmit side a timing reference and tells implementers how tightly the modulator has to track it.

Clause 2 also defines an 11-bit asynchronous serial byte format with a start bit, 8 data bits, an odd parity bit and a stop bit. The data bytes are sent LSB first. For a reader, this means the receiver-to-transmitter channel is not just a raw signal - it has byte framing and error checking built in.

For packets, Clause 2 requires a preamble, header, message and checksum. The preamble is used for synchronization, the header identifies the packet type and implies the message length, and the checksum is used to detect transmission errors. If a packet is received incorrectly, the transmitter discards it and does not use the contents.

Clause 3 - Power Transmitter to Power Receiver FSK

prEN IEC 63758-10:2026 uses frequency-shift keying (FSK) for the Power Transmitter to Power Receiver direction. The transmitter switches the Operating Frequency between unmodulated and modulated states, with polarity and depth defining the frequency difference. This matters because the receiver must be able to detect the transmitter’s command or data signal while the power link is still operating.

The bit encoding again uses differential bi-phase timing. The bit length is tied to the number of cycles in the Power Transfer Contract, with a default value given in the document, and the receiver must tolerate limited cycle-count variation. In practice, implementers need a decoder that can handle small timing spread without losing data.

Clause 3 uses the same 11-bit asynchronous serial structure as the other direction, but with even parity instead of odd parity. That difference is important for interoperability and for keeping the two communication directions distinct.

The packet structure in Clause 3 consists of a header, message and checksum sent as a contiguous sequence with no pauses between bytes. A packet is valid only if the start and stop bits are correct, the parity bits are correct, and the checksum matches. Incorrect packets are discarded.

Clause 3 also defines a Response Pattern for simple query packets. The four patterns are ACK, NAK, ND and ATN. That gives the receiver a compact way to tell the transmitter whether a query was accepted, rejected, not defined or should draw attention.

What terms does prEN IEC 63758-10:2026 define?

prEN IEC 63758-10:2026 uses a small set of core terms that are central to implementation.

• Wireless Power Consortium (WPC) - the organization described as developing and promoting global standards for wireless power transfer.
• Power Signal - the power-transfer signal that also carries Qi communications.
• Power Receiver - the device that receives power and sends load-modulated or FSK-related communications.
• Power Transmitter - the device that supplies power and decodes the incoming communications.
• Primary Cell - the current and voltage point used to observe the receiver’s load modulation.
• Operating Frequency - the frequency that the transmitter shifts in the FSK channel.
• Response Pattern - one of the fixed eight-bit patterns used to answer a simple query.
• Checksum - the final byte used to detect transmission errors in a packet.

Who uses prEN IEC 63758-10:2026?

prEN IEC 63758-10:2026 is used by engineers designing Qi wireless power products, especially flat-surface devices such as mobile phones and chargers operating at power levels up to 25 W. It is also used by teams building the transmitter and receiver electronics that have to exchange status, requests and acknowledgements over the power link.

Test laboratories and compliance teams use it to check modulation depth, timing, framing and packet integrity. Quality managers and buyers can use it to verify that a product’s Qi communications implementation matches the packet and encoding rules expected by the system.

Which standards are used with prEN IEC 63758-10:2026?

prEN IEC 63758-10:2026 refers to these companion documents and rules:

• ISO/IEC Directives, Part 2 - provides the verbal forms used for requirements, recommendations, permissions and capabilities.
• QiSpecification, Communications Protocol - defines packet mnemonics, message meanings and the packet classifications used by the physical layer.
• QiSpecification, Power Delivery - provides related Qi communication context, including the note on odd parity for receiver-to-transmitter communications.

What does the prEN IEC 63758-10:2026 document contain?

prEN IEC 63758-10:2026 contains the conventions for numbers, tolerances, packet fields, text strings and packet shorthand, followed by the detailed communication rules for both directions. It includes tables and figures for load modulation timing, differential bi-phase encoding, asynchronous serial byte format, packet structure, checksum handling, message sizing and packet start/end timing.

The document also contains the FSK state table, the receiver’s tolerance to cycle-count variation, the FSK packet format and the Response Pattern definitions. These parts are used when designing hardware, writing firmware, building decoders and running interoperability or conformance tests.

Tables 2 to 8 and Figures 1 to 11 provide the worked structures and timing layouts needed to implement the physical layer correctly without reproducing the full normative text in a design note.

SLOVENSKI STANDARD
01-november-2026
Specifikacija Qi - Različica 2.3 - 10. del: Fizična raven komunikacije (hitri
postopek)
Qi Specification - Version 2.3 - Part 10: Communications physical layer (Fast Track)
Ta slovenski standard je istoveten z: prEN IEC 63758-10:2026
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.

100/4553/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 63758-10 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 10: Communications physical layer (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
CommunicationsPhysicalLayer
Version2.3
PublishDate:08December2025
DISCLAIMER
The information contained herein is believed to be accurate as of the date of publication, but is provided “as is” and may
contain errors. The Wireless Power Consortium makes no warranty, express or implied, with respect to this document
and its contents, including any warranty of title, ownership, merchantability, or fitness for a particular use or purpose.
Neither the Wireless Power Consortium, nor any member of the Wireless Power Consortium will be liable for errors in
this document or for any damages, including indirect or consequential, from use of or reliance on the accuracy of this
document. For any further explanation of the contents of this document, or in case of any perceived inconsistency or
ambiguity of interpretation, contact: [e-mail].

Contents
1. General 4
1.1 StructureoftheQi Specification 4
1.2 Scope 5
1.3 Compliance 5
1.4 References 5
1.5 Conventions 6
1.5.1 Notationofnumbers 6
1.5.2 Tolerances 6
1.5.3 Fieldsinadatapacket 6
1.5.4 Notationoftextstrings 7
1.5.5 Short-handnotationfordatapackets 7
2. LoadModulation 8
2.1 Modulationscheme 8
2.2 Bitencodingscheme 9
2.3 Byteencodingscheme 10
2.4 Datapacketstructure 10
2.4.1 Header 11
2.4.2 Message 11
2.4.3 Checksum 11
2.4.4 Correctreceptionofadatapacket 12
2.4.5 Startandendofadatapacket 12
3. Frequency-shiftkeying 13
3.1 Modulationscheme 13
3.2 Bitencodingscheme 14
3.3 Byteencodingscheme 15
3.4 Datapacketstructure 16
3.4.1 Header 16
3.4.2 Message 17
3.4.3 Checksum 17
3.4.4 Correctreceptionofadatapacket 17
3.4.5 Startandendofadatapacket 17
3.5 ResponsePattern 18
1. General
The Wireless Power Consortium (WPC) is a worldwide organization that aims to develop and promote global standards
for wireless power transfer in various application areas. An important application area comprises flat-surface devices
such as mobile phones and chargers operating at power levels up to 25 W.
1.1 StructureoftheQi Specification
Generaldocuments
l
Introduction
l
Glossary, Acronyms, and Symbols
l
Technical System Overview
l
Power Profiles
Systemdescriptiondocuments
l
Mechanical, Thermal, and User Interface
l
Power Delivery
l
Communications Physical Layer
l
Communications Protocol
l
Foreign Object Detection
l
NFC Tag Protection
l
Authentication Protocol
l
MPP Communications Protocol
l
MPP Magnetics Design
l
MPP Power Delivery
l
MPP Communications Physical Layer
l
MPP Foreign Object Detection
l
MPP Design Guidelines (Informative)
l
Magnetic Covers
l
Active Alignment System
l
Thermal Management Protocol
1.2 Scope
TheQiSpecification,CommunicationsPhysicalLayer (this document) defines the low-level (physical layer and the data
link layer) formats of data bits, data bytes, and data packets. In addition, it provides requirements and guidelines for
load modulation and frequency-shift keying.
1.3 Compliance
All provisions in theQiSpecification are mandatory, unless specifically indicated as recommended, optional, note,
example, or informative. Verbal expression of provisions in this Specification follow the rules provided in ISO/IEC
Directives, Part 2.
Table1-Verbalformsforexpressionsofprovisions
Provision Verbalform
requirement “shall” or “shall not”
recommendation “should” or “should not”
permission “may” or “may not”
capability “can” or “cannot”
1.4 References
For undated references, the most recently published document applies. The most recent WPC publications can be
downloaded from http://www.wirelesspowerconsortium.com.

1.5 Conventions
1.5.1 Notationofnumbers
l
Real numbers use the digits 0 to 9, a decimal point, and optionally an exponential part.
l
Integer numbers in decimal notation use the digits 0 to 9.
l
Integer numbers in hexadecimal notation use the hexadecimal digits 0 to 9 and A to F, and are prefixed by "0x"
unless explicitly indicated otherwise.
l
Single bit values use the words ZERO and ONE.
1.5.2 Tolerances
Unless indicated otherwise, all numeric values in theQiSpecification are exactly as specified and do not have any
implied tolerance.
1.5.3 Fieldsinadatapacket
A numeric value stored in a field of a data packet uses a big-endian format. Bits that are more significant are stored at a
lower byte offset than bits that are less significant. Table 2 and Figure 1 provide examples of the interpretation of such
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
Text strings consist of a sequence of printable ASCII characters (i.e. in the range of 0x20 to 0x7E) enclosed in double
quotes ("). Text strings are stored in fields of data structures with the first character of the string at the lowest byte
offset, and are padded with ASCII NUL (0x00) characters to the end of the field where necessary.
EXAMPLE: The text string “WPC” is stored in a six-byte fields as the sequence of characters 'W', 'P', 'C', NUL, NUL, and
NUL. The text string “M:4D3A” is stored in a six-byte field as the sequence 'M', ':', '4', 'D', '3', and 'A'.
1.5.5 Short-handnotationfordatapackets
In many instances, theQiSpecification refers to a data packet using the following shorthand notation:
/
In this notation, refers to the data packet's mnemonic defined in theQiSpecification,Communications
Protocol, and refers to a particular value in a field of the data packet. The definitions of the data packets in
theQiSpecification,CommunicationsProtocol, list the meanings of the modifiers.
For example, EPT/cc refers to an End Power Transfer data packet having its End Power Transfer code field set to 0x01.

2. LoadModulation
This section defines both the physical layer and the data link layer of the Power Receiver to Power Transmitter
communications interface.
The Power Receiver communicates to the Power Transmitter using backscatter modulation. For this purpose, the Power
Receiver modulates the amount of power that it draws from the Power Signal. The Power Transmitter detects this as a
modulation of the current through and/or voltage across the Primary Cell. In other words, the Power Receiver and
Power Transmitter use an amplitude modulated Power Signal to provide a Power Receiver to Power Transmitter
communications channel.
2.1 Modulationscheme
The Power Receiver shall modulate the amount of power that it draws from the Power Signal, such that the Primary Cell
(i)
current and/or Primary Cell voltage assume two states, namely a HI state and a LO state. A state is characterized in
that the amplitude is constant within a certain variation for at least ms. If the Power Receiver is properly aligned
to the Primary Cell of a type A10 or MP-A1 Power Transmitter, and for all appropriate loads, at least one of the
(ii)
following three conditions shall apply:
l
The difference of the amplitude of the Primary Cell current in the HI and LO state is at least 15 mA.
l
The difference of the Primary Cell current in the HI and LO state is at least 15 mA. The Primary Cell current is
measured at instants in time that correspond to one quarter of the cycle of the control signal driving the half-
(iii)
bridge inverter.
l
The difference of the amplitude of the Primary Cell voltage in the HI and LO state is at least 200 mV.
During a transition, the Primary Cell current and Primary Cell voltage are undefined. See Figure 2 and Table 3.
tS tS
tT
tT
t
S
HI state HI state tS
LO state LO state
Modulation
Δ
depth
Δ
100%
Figure2-AmplitudemodulationofthePowerSignal
(i)
The HI and LO states do not correspond to fixed Primary Cell current and/or Primary Cell voltage levels.
(ii)
The design requirements of the Mobile Device determine both the range of lateral displacements that constitute
proper alignment and the range of loading conditions on its Power Receiver.
(iii)
The start of the cycle corresponds the closing of the top switch in the half-bridge inverter.
Primary Cell current
Primary Cell voltage
Table3-AmplitudemodulationofthePowerSignal
Parameter Symbol Value Unit
Maximum transition time 100 μs
Minimum stable time 150 μs
Current amplitude variation 8 mA
Voltage amplitude variation 110 mV
2.2 Bitencodingscheme
The Power Receiver shall use a differential bi-phase encoding scheme to modulate data bits onto the Power Signal. For
this purpose, the Power Receiver shall align each data bit to a full period of an internal clock signal, such that the
start of a data bit coincides with the rising edge of the clock signal. This internal clock signal shall have a frequency
= (2 ± 4%) kHz.
NOTE: A ripple on the Power Receiver’s load yields a ripple on the Power Transmitter’s current. As a result, such a ripple can lead to
bit errors in the Power Transmitter. The number of bit errors can be particularly high if this ripple has a frequency that is
close to the modulation frequency .
The Receiver shall encode a ONE bit using two transitions in the Power Signal, such that the first transition coincides
with the rising edge of the clock signal and the second transition coincides with the falling edge of the clock signal. The
Receiver shall encode a ZERO bit using a single transition in the Power Signal, which coincides with the rising edge of
the clock signal.
t
CLK
ONE ZERO ONE ZERO ONE ONE ZERO ZERO
Figure3-Exampleofadifferentialbi-phaseencodingscheme

2.3 Byteencodingscheme
The Power Receiver shall use an 11-bit asynchronous serial format to transmit a data byte. This format consists of a
start bit, the 8 data bits of the byte, a parity bit, and a single stop bit. The start bit is a ZERO. The order of the data bits
is LSB first. The parity bit is odd. This means that the Power Receiver shall set the parity bit to ONE if the data byte
contains an even number of ONE bits. Otherwise, the Power Receiver shall set the parity bit to ZERO. The stop bit is a
ONE. Figure 4 shows the data byte format—including the differential bi-phase encoding of each individual bit—using the
value 0x35 as an example.
Start b0 b1 b2 b3 b4 b5 b6 b7 Parity Stop
Figure4-Exampleoftheasynchronousserialformat
2.4 Datapacketstructure
The
...