GB2641026A - Wireless power transfer recovery - Google Patents

Abstract

A method for managing wireless power delivery between a first wireless power apparatus to a second wireless power apparatus, the method comprising: Receiving 1401 information for use in identifying whether a power delivery was previously performed between the first and second wireless power apparatuses; and in the case where the information identifies that power delivery was previously performed between the first and second wireless power apparatuses, establish 1402 a further power delivery between the first and second wireless power apparatuses based on the power delivery previously performed between the first and second wireless power apparatuses. Power delivery may involve the use of a power profile of stored information if power delivery was previously performed 1404.

Description

WIRELESS POWER TRANSFER RECOVERY

FIELD OF THE INVENTION

The present disclosure relates to a Wireless power Transmission system. In particular, aspects of the disclosure aim to provide an improved method of wireless power transmission between a power transmitter and a power receiver. Accordingly, aspects of the disclosure provide a fast solution to recover a wireless power transfer profile using a previous power transfer (delivery) experience between a power transmitter and a power receiver. Aspects of the present disclosure relate, particularly but not exclusively, to a means or process for recovering a previous charging power profile used between the same wireless power transmitter and wireless power receiver. The present disclosure also generally relates to a means and/or process for establishing power transfer between a wireless power transmitter and a wireless power receiver based on a previous power transfer between the same transmitter and receiver. Aspects of the disclosure particularly but not exclusively relate to a means or process of identifying when a wireless power transmitter and a wireless power receiver have established a power transfer previously.

BACKGROUND OF INVENTION

Wireless power charging is used nowadays in consumer applications such as smartphones, tablets and smart watches. Further applications of wireless power transfer technologies include medical or dental applications, home appliances, electric vehicles or fields which may require electrical power.

The fast-growing wireless charging market has motivated the manufacturers to find a global wireless charging standard for interoperability between devices. Most products rely on magnetic induction or magnetic resonance wireless charging technologies. The Wireless Power Consortium (WPC) is one of the open standard development groups working on these technologies to set global standards for safety, efficiency and interoperability. WPC has developed wireless power transfer standards related to Wreless mobile device charging (Qi), cordless kitchen appliances (Ki) and Light Electric vehicles (LEV). It combines magnetic induction and resonance technologies.

This disclosure relates particularly but not exclusively to the Qi standard using magnetic induction for wireless power transfer. The magnetic induction is based on transmitter and receiver coils being tightly coupled together. To guarantee the best power transmission between coils, the coils should be coupled in an optimum manner in order to maximize the coupling factor k between coils. The coupling factor k depends upon the shape of the inductors, the angle between the inductors and the distance between inductors. In order to transmit wireless power efficiency in a magnetic induction system, the transmitter and the receiver coils should be of same diameter and aligned with minimal distance between them. This tight coupling allows for less heat to be produced and for higher efficiency wireless power transfer. Multiple Qi generations have been published in the recent years. The Qi standard has launched its first generation of Baseline Power Profile (BPP) in 2010 with 5W wireless power transfer. The subsequent versions have included new profiles with higher power transmission up to 15 W (e.g., Extended Power Profile (EPP)) and new features to address issues related to Foreign Object Detection (FOD). The latest version of the Qi specification (Qi 2.0) has introduced the Magnetic Power Profile (MPP) to enhance the coupling between coils by adding a magnet ring.

In Qi based wireless power transmission systems, the control of how the coils are powered is done via a control unit at the power transmitter (PTx) side and a control unit at the power receiver (PRx) side. The PTx and PRx communicate with each other using in-band communication with data modulation (Either amplitude or frequency based) on the power carrier frequency. A Qi-compliant device uses a power carrier frequency of 128 kHz, and in the newest version of the Qi standard the Qi-compliant device uses an additional power carrier frequency of 360 kHz after communication is performed on the 128kHz power carrier frequency.

The communication protocol as specified in the Qi standard should be backward compatible i.e. it should be possible to use newer devices, either PRx or PTx, which are compliant with a newer version of the Qi standard and capable of greater than 5W wireless charging (using MPP or EPP) with older devices, either PRx or PTx, compliant with the first version of the Qi standard and are only capable of 5W or less wireless charging (using only BPP). A first communication between PRx and PTx is performed using the power carrier frequency of 128kHz so as to be compatible with the first Qi version using BPP. Once power transfer has been established for up to 5W wireless charging, a second communication between the PRx and PTx is performed before going to the full power delivery above 5W to check compatibility and determine settings. The second communication is performed at either 128 kHz or 360 kHz power carrier frequencies for EPP or MPP respectively. Prior going to full power delivery, i.e. a higher-power mode, the PRx may need to configure the PTx, negotiate the power contract elements and then validate the authentication of the PTx. The configuration and the negotiation phases may occur as much time as needed to establish the power contract elements including the operating frequency, the power loss accounting, the power level, for example.

Due to the backward compatibility requirement discussed above, the PTx and PRx shall perform multiple configuration and negotiation phases, both at 128 kHz and 360 kHz, before the most appropriate power transfer profile can be established. The most appropriate power transfer profile is chosen so as to permit the maximum wireless power transfer between the PTx and PRx.

The communication protocol as specified in Qi standard for establishing wireless power transfer defines identification messages.

Using identification messages, PTx and PRx can detect that one of the devices have been changed (replaced by another device) or removed and later replaced. In such cases, the wireless power transfer is stopped and the overall process of configuration and negotiation is restarted.

Due to privacy considerations, as specified in Qi standard, PRx and PTx identifiers exchanged in the identification messages are randomly generated values which change between wireless power transfer experiences.

An authentication phase is a mandatory phase in the communication protocol defined in the Qi standard. The authentication phase is provided in order to protect the Qi brand and safeguard end users, specifically their devices having wireless power receivers (PRx), from counterfeit power transmitters (PTx) that may damage the PRx. WPC has added the mandatory support of authentication at the PTx side for all power transmitters offering power charging above 5W, starting from Qi 1.3 version.

The authentication phase plays a major role in minimizing product damage and end user safety risk for better user experience. In order to ascertain the authenticity of a power transmitter device (PTx), i.e. a genuine Qi-compatible product, a Qi single unique certificate is installed in each power transmitter during manufacturing process. This unique certificate is a combination of WPC and manufacturer certificates attesting that the transmitter satisfies all Qi certification requirements.

The authentication phase consists of a first step requiring the PTx certificate to be sent and then validated by the PRx followed by a second step where the PRx challenges the PTx to send a response signed with the transmitter's unique private key for further validation. Upon successful two-steps validation, the PRx and the PTx may negotiate to bring the power level above 5W. The authentication exchanged messages are done using in-band communication with ASK modulation at receiver side and FSK modulation at transmitter side. As the in-band communication uses magnetic induction, the data rate is very low, typically in the order of few kbits/sec.

Although the authentication protocol ensures the authenticity of the power transmitter and protects the power receivers, the PTx certificate needs an exchange of a huge number of packets with the PRx which may take a few seconds to be received correctly. Any error in the sending of the certificate may require a retransmission of the certificate again leading to a delay while the data packets are exchanged again.

Thus, the communication protocol as in the recent specification requires an estimated time between 15-30 seconds before activating the full power, i.e. high-powered, delivery mode.

Accordingly, it is desirable to provide a better user experience with a communication protocol which improves the speed at which high-powered wireless power transfer can safely take place, i.e. reduce the latency, while maintaining privacy, backwards compatibility and authentication.

SUMMARY OF THE INVENTION

The present disclosure addresses one or more of the foregoing issues.

An aspect of the present disclosure is provided by a method of managing wireless power transfer (delivery) between a first wireless power apparatus (device) and a second wireless power apparatus (device) as set out in claim 1. Optional features are presented in claims 2 to 52 Another aspect of the present disclosure is provided by a wireless power transmitter apparatus as set out in one or more of the appended claims.

Another aspect of the present disclosure is provided by a wireless power receiver apparatus as set out in one or more of the appended claims.

The disclosure advantageously allows for a first device and a second device to recover (resume) a power transfer (power delivery) experience they previously shared together. That is to say that a wireless power transmitter and a wireless power receiver is able to establish a power transfer over 5 Watts, i.e. high power or full power, e.g. MPP or EPP, based on a previous power transfer between the same devices at over 5 Watts. The further power transfer experience may be considered a recovered or resumed power transfer experience because it is between the same devices and, preferably, with the same power profile.

By using previous power transfer experiences, i.e. a wireless power delivery (preferably at a high power mode) between the same devices, to inform a further power transfer experience between the same devices it is possible to increase the speed at which charging between the same devices are able to achieve high power, i.e. over 5 Watt, whilst taking into account existing Qi communications protocol and requirements such as privacy, backward compatibility, and authentication of trusted devices for power transfer over 5 Watts.

Devices involved in a power transfer, PTx and PRx, may memorize information, e.g. the power transfer profile and/or identification values randomly generated, which permits the devices to achieve the optimal power transfer after multiple configuration phases, negotiation phases and/or authentication phase during a first experience.

Preferably, one or both of the devices involved in a power transfer experience, such as the PTx and/or PRX, may comprise a means to store, or record, information from one or more power transfer experiences. That is to say that one or both of the first wireless power apparatus, preferably a wireless power transmitting apparatus, and a second wireless power apparatus, preferably a wireless power receiver apparatus may memorize information associated with, or related to, one or more previous power transfer experiences. Preferably, the information memorized, i.e. stored or recorded, is information which permits the devices to achieve optional power transfer between the devices. The information may comprise at least one of power transfer profile, i.e. mode and identifier values, i.e. identification information such as identifiers. Each previous power transfer experience may comprise a set of information associated with that power transfer experience.

Preferably, by memorizing the information associated or related to an optional power transfer previously performed between the two devices after multiple configuration negotiation and/or authentication phases, it is possible to increase the speed at which a high power mode can be achieved while maintaining a level of privacy. In some cases, the level of privacy maintained depends on the number of previous power transfer experiences maintained or how long each previous power transfer experience is maintained in the memory.

The memorized, i.e. stored or recorded, information may comprise at least one of identification information, preferably identifiers, for identifying one or both the first and second wireless power apparatuses, information for identifying a power transfer mode used for the previously performed power transfer experience, information associated with an authentication process between the apparatus, and information for identifying time of the previously performed power transfer. Each item of information may be stored in a relationship, preferably all the items of information associated with one previous power transfer are memorized in a relationship to allow easy identification. Preferably, the items of information are indexed.

Preferably, the information for identifying the power transfer mode indicates a non-Baseline Power Profile mode. Preferably, the information associated with an authentication process comprises certificate information, i.e. information associated with the certificates and/or challenges in the authentication of the power transfer phase of the previously performed power transfer experience. Preferably the certificate information is a certificate chain.

A first charging experience between the wireless charging devices, PTx and PRX, may take some time, using information from the first power transfer experiences will allow the second, or subsequent, power transfer experiences to be quicker.

During a next, or subsequent experience between the same devices, a first device, PRx or PTx, may request the other device, respectively PTx or PRx, to recover a previously used power transfer profile. This request may be in the form of providing information from a previous power transfer experience, which may or may not be signified by an indicator, or an explicit request which asked the other device for information from a previous power transfer. The second device may respond to the first device with it memorized information, such as a device identifier. The first device, upon receiving the device identifier from the second device, may determine if said identifier corresponds to an identifier used in one or more previous power transfer experiences. Based on the received information the first device may decide to quickly establish a power transfer between the device, for example by using the same power transfer profile used in the first power transfer experience.

The first wireless power apparatus may receive information for use in identifying whether a power transfer was previously performed between the first and second wireless power apparatuses. This information received by the first wireless power apparatus may comprise an identifier from the second wireless device used in a previous power transfer and/or an indicator which may be used to indicate a request for information associated with a previous power transfer or indicating whether information provided is from a previous power transfer.

The first wireless power apparatus, after receiving information for use in identifying whether a power transfer was previously performed, may check information stored in the first wireless power apparatus, i.e. the information memorized by the first wireless power apparatus. The check may be based on the received information, for example by using a received identifier to check the memorized information for a record of the same identifier or by using the received indicator to check whether there is any memorized information from previous power transfers.

The first wireless power apparatus may send further information in response. In some embodiments the second wireless power apparatus may also send further information in response to information sent from the first wireless power apparatus. The further information may be information for identifying whether the power transfer was previously performed between the first and second apparatus, i.e. the information is information associated with the previous performed power transfer experience and to send one or more identifiers, or indicators, in response.

The sending of information associated with a previous power transfer provides information which can indicate whether or not a power transfer happened between the same devices. Sending further information acts as a further verification because the receiving device is able to check that the information is associated with the information it had previously sent. The second wireless power apparatus may receive information for use in identifying whether power transfer was previously performed. The information received by the second wireless power apparatus may be further information sent from the first wireless device.

The second wireless power apparatus, after receiving information, or the further information, for use in identifying whether a power transfer was previously performed, may check information stored in the second wireless power apparatus, i.e. the information memorized by the second wireless power apparatus. The check may be based on the received information, for example by using a received identifier to check the memorized information for a record comprising the same identifier.

The second wireless power apparatus may send information for use in identifying whether power transfer was previously performed between the first and second wireless power apparatuses.

The second wireless device may, especially when being a power receiver, be the final determiner when to establish the further power transfer. The second wireless device may establish the further power transfer based on the identified previously performed power transfer.

The information for use in identifying whether a power transfer was previously performed may comprise apparatus identification information. The apparatus identification information may be an identifier of one or more of the apparatuses. That is to say that the identification information may comprise a single device identifier or an identifier for both first and second wireless power apparatus.

Preferably, each apparatus will send the identifier for itself used, i.e. a first wireless power device identifier is sent by the first wireless power apparatus and a second wireless power device identifier is sent by the second wireless power apparatus.

The identifier(s) sent or received may be generated during the previously performed power transfer, that is to say that it was the apparatus identifier used during the previously performed power transfer. This is especially useful since the device's identifier is dynamic and comprise a randomly generated value.

Further information for use in identifying whether power transfer was previously performed may comprise further identification information. The further identification information may be an identifier of at least one of the first wireless power apparatus and the second wireless power apparatus. That is to say that the identification information, e.g. the identifier, preferably sent between the apparatus, is identification information used in a previously performed power transfer.

By receiving identification information from a previous power transfer, an apparatus is able to determine whether or not a power transfer happened with the sending apparatus. The exchange of previous identifiers between the devices allows the devices to cross-reference and verify that a power transfer previously happened. This allows for a level of privacy to be maintained.

The identification information, e.g. the apparatus identifier, may comprise a fixed value. That is to say that the identifier for the device may remain fixed, i.e. time invariant, between different power transfer experiences, be it between the same or different apparatus. Preferably, only the first wireless power device comprises the fixed value identifier. More preferably, the wireless power transmitter comprises the fixed value identifier.

The fixed value identifier reduces the overall level of privacy but can increase the speed of determining whether there was a previous power transfer experience between the apparatuses. In cases where a fixed value identifier is used for one device, the level of privacy can be improved by having the other device use dynamic values.

The information for identifying whether a power transfer experience was previously performed may comprise indicator information. The indicator information may be for indicating a request for identification information. The indicator information may be for indicating intention for a further power transfer to be established based on a previously performed power transfer. The indicator information may be for indicating whether information from a power transfer previously performed is present.

The information for identifying whether a previous power transfer experience occurred may be provided in a message. The message may be a message defined in the Qi standard, i.e. an existing message. The message defined in the Qi standard may have a field for identification information. Preferably the message may be at least one of A basic Identification message, a GET request identification message, A Report message and an Extended Power identification message.

The message may comprise at least one field configured to comprise information for indicating information is from a previously performed power transfer, a request for information or an intention to enable a further power transfer based on a previously performed power 25 transfer.

A power transfer experience may comprise a power profile, i.e. a power transfer mode. A power transfer experience may have one or more power profiles. Preferably, the memorized power profile is the high power profile.

A power profile of the further power transfer experience may be based on the power profile of the previous power transfer experience. Preferably the power profile of the further power transfer may be the same power profile of the previous power transfer experience between the apparatuses. The power profile of the further power transfer experience could be considered a recovered or resumed power profile.

Put another way, the previous power transfer may comprise a first power profile and the further power transfer may comprise a second power profile. The first and second power profiles may be the same power profile, i.e. the second power profile is selected to be the same as the first power profile.

Preferably, the power profiles are a full or high power delivery mode. That is to say that the power profile for the previous power transfer experience and the power profile of a further power transfer delivery are a full or high power delivery mode. Preferably, full power or high power mode is a non-Baseline Power Profile, non-N PP. The non-BPP profiles may be an extended power profile, EPP, or a magnetic power profile, M PP. The further power transfer may be established, or enabled, prior to performing an authentication process between the first and second wireless power apparatuses. The further power transfer may be halted upon a failed authentication. The authentication process may not be performed for the further power transfer.

Preferably, a notification may be provided to a user. The notification may be provided to a user to allow them to identify that one of the first wireless power apparatus and/or the second wireless power apparatus is a trusted device. The notification may be issued in the case where the received information identifies that a power transfer was previously performed between the first and second wireless power apparatuses.

Preferably, one of the devices may inform the end user using a device user interface, such as a screen to issue an alert or notification. The alert may be delivered faster thanks to the quick establishment of the memorized power transfer profile. This alert can be delivered to end user as soon as the power profile is determined.

Preferably, the first wireless power apparatus is a wireless power transmitter apparatus.

Preferably, the second wireless power apparatus is a wireless power receiver apparatus.

Preferably, the power transfer, both previous and further, are performed in accordance with one or more steps of a Qi specification.

The request to recover a previously used power transfer profile may be based on the exchange of PTx and PRx identifiers.

Also, the request to recover a previously used power transfer profile may be based on the request from a PRx to PTx to response with a PTx identifier value being time-Invariant between different power transfer experience.

The PTx identifier value may be time-Invariant. The time-invariant identifier may be set to the PRx identifier value used during a previous identification (PRx sending identifier).

The memorized data information may include different power transfer profile such as EPP, M PP or any proprietary profile for higher than 15W power profile.

Multiple experiences, i.e. multiple power transfers, may be memorized using multiple memorized information. That is to say that the or each apparatus may memorize information for a plurality of previous power transfers, each memorized previous power transfer comprising multiple items of information.

The memorized data information may include a certificate chain of PTx from a previous power transfer experience. During a second power transfer experience with the same PTx, the memorized certificate chain can be reused and it permits to achieve a faster authentication. The memorized data information may include a timestamp with the value of the memorized previous power transfer experience. Advantageously the different timestamps of memorized data information from multiple previous experiences can be used to order the different previous experiences, to select the most recent and to erase the older ones. For example, a memorized data information of a previous experience having timestamp being less than 24 hours older from the current time can be considered as the most recent. In another example, a memorized data information of multiple previous experiences having timestamp being more than 1 month older than the current time can be considered as the older ones and can be erased.

According to another aspect of the disclosure, it is proposed a computer program product for a programmable apparatus, the computer program product comprising a sequence of instructions for implementing a method according to the disclosure, when loaded into and executed by the programmable apparatus.

According to another aspect of the disclosure, it is proposed a computer-readable storage medium storing instructions of a computer program for implementing a method according to the disclosure.

According to another aspect of the disclosure, it is proposed a computer program which upon execution causes the method of the invention to be performed.

At least parts of the methods according to the invention may be computer implemented. Accordingly, the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit", "module" or "system". Furthermore, the present disclosure may take the form of a computer program product embodied in any tangible medium of expression having computer usable program code embodied in the medium.

Since the present disclosure can be implemented in software, the present disclosure can be embodied as computer readable code for provision to a programmable apparatus on any suitable carrier medium. A tangible carrier medium may comprise a storage medium such as a hard disk drive, a magnetic tape device or a solid-state memory device and the like. A transient carrier medium may include a signal such as an electrical signal, an electronic signal, an optical signal, an acoustic signal, a magnetic signal or an electromagnetic signal, e.g. a microwave or RF signal.

BRIEF DESCRIPTION OF THE DRAWINGS

Different embodiments will now be described, by way of example only, and with reference to the following drawings in which: Figure 1 is a block schematic diagram of a wireless power charging system with a power transmitter apparatus and a power receiver apparatus in which one or more embodiments may be implemented; Figure 2 is a block schematic diagram of Qi communications protocol phases 200; Figure 3 is a block schematic diagram showing communications protocol operating mode for Qi-compliant devices; Figures 4a and 4b illustrate an example of Magnetic Power Profile communications protocol for Qi-compliant devices; Figure 5 illustrates data packet structure as specified in the communications protocol operating mode for Qi-compliant devices; Figure 6 illustrates Identification message used during PTx and PRx identifiers exchange as specified in the communications protocol operating mode for Qi-compliant devices; Figure 7 is a flowchart illustrating the exchange of identification messages between PRx and PTx as specified in the communications protocol operating mode considering MPP for Qi-compliant devices; Figure 8 illustrates an example format of the memorized data information during one or more previous power transfer experiences by a device in accordance with embodiments; Figure 9 illustrates, using a flowchart, steps of methods to recover power transfer from a previous experience according to embodiments; Figure 10 illustrates, using a flowchart, more detailed steps of methods to recover power transfer from a previous experience according to embodiments; Figure 11 illustrates, using a flowchart, another more detailed steps of methods to recover a power transfer from a previous experience according to embodiments; Figure 12 is a flow diagram showing an example of Magnetic Power Profile (MPP) communications protocol for Qi-compliant devices according to embodiments; Figure 13 is a block schematic diagram of an example of wireless charging device in accordance with embodiments; Figure 14 illustrates, using a flowchart, steps of a method to record a power transfer from a previous power delivery experience.

DETAILED DESCRIPTION

Figure 1 is a block schematic diagram of a wireless power charging system with a power transmitter apparatus and a power receiver apparatus in which one or more embodiments according to the present disclosure may be implemented.

As mentioned above, the time required with the current Qi specifications for delivering the maximum power, i.e. high power mode or full power mode, charging and in particular MPP or EPP profiles is disadvantageous and impacts some user experiences. For example, an end user using a power receiver, PRx, may have a first experience with a PTx, in the first experience a full power delivery, i.e. high-powered or full power charging, may be established between the PRx and PTx. During this first experience, the end user will have to wait plural seconds, as discussed above, to get feedback from his PRx device that the wireless power transfer is operating at the maximum possible power, i.e. high-powered mode or full power charging.

In a second experience, subsequent to the first experience, involving the same PRx and the same PTx, the end user will have to wait again plural seconds to get feedback from the PRx device that the wireless power transfer is operating at the maximum possible power because the same PTx will lead to the same process including the multiple configuration and negotiation phases and the authentication phase. Thus, the communication protocol suffers from high latency and low proactiveness.

Figure 1 shows the system architecture 100 for WPC-compliant devices. The system architecture 100 is composed of a contactless/wireless power transmitter PTx 101, a contactless/wireless power receiver PRx 102 and Qi accessory 103. The PTx 101 wirelessly transmits power to the PRx 102. In embodiments, the elements of the power transmitter, PTx, 101 may form part of a Base Station and the power receiver PRx 102 may form part of a mobile device, such as a smart phone. The present disclosure references the WPC specification, i.e. the Qi standard. However, it will be appreciated that it is not limited to WPC specifications only and may be used in any contactless/ wireless charging specifications. WPC introduced Qi Wireless charging in 2010 with the Baseline Power Profile (BPP) that allowed the PTx to deliver power up to 5W. The BPP power profile was the only available mode for the first Qi specification versions 1.0 and 1.1.

The Qi standard has introduced in version 1.2 the Extended Power Profile (EPP) with a power delivery up to 15W. Version 1.3 added an authentication process for a safer, consistent and reliable wireless power charging. The operating frequency for both BPP and EPP power profiles is 128 kHz.

A recent version of the Qi 2.0 specification has introduced a new Magnetic Power Profile (MPP) together with a few updates to legacy BPP and EPP power profiles. The MPP power profile adds magnetic ring features to guarantee the tight alignment of the primary coil 101e and the secondary coil 102a in order to ensure safer power transfer up to 15W and an increase of the efficiency. The MPP power profile operates at 360 kHz to mitigate interference with nearby vehicle key fobs.

The PTx 101 includes a power control unit 101b that provides overall control of the overall power units comprising power transmitting apparatus. The different units 101a-h may be a part of the power transmitter system architecture.

The PRx 102 includes a power control unit 102b that provides overall control of the units comprising the power receiving apparatus. The different units 102a-h may be a part of the power receiver system architecture.

An external power source PIN is applied to the variable voltage supply 101a in PTx 101 to control the DC voltage of the input power signal. The DC power supplied by the variable voltage supply 101a is converted by the inverter 101c, acting as a power conversion unit, to AC power. The inverter 101c is a full bridge DC/AC converter that generates the AC power signal from DC power. To control the magnitude of the power transfer between PTx 101 and PRx 102, the DC voltage of the inverter in 101c is regulated and controlled.

At the PRx side 102, the power conversion unit 102d consists of a rectifier which converts the AC power received to DC power in order to supply the load 102e.

The resonant circuit 101d and 102c are switched capacitors in series with the coil to boost power transfer capability and to support both BPP and non-BPP modes (e.g., EPP and MPP). The MPP mode in the Qi 2.0 specification has an operating frequency range outside of the existing BPP frequency range and therefore requires different tuning capacitors on both the PTx 101 and PRx 102 for high and efficient power transfer. Because of this, both the PTx 101 and the PRx 102 employs switchable tuning capacitors to support both MPP and BPP operating frequencies.

The power is transferred wirelessly from the primary coil 101e to the secondary coil 102a via the Qi accessory unit 103. The 103 unit may include the non-magnetic keep-out area between coils, the magnetic ring specific to MPP mode and other communication protocols such as RFID.

To ensure safe and efficient battery (102e) charging, battery management systems in the power receiver 102 (e.g., mobile devices) requires information from the power transmitter (e.g., power source or the charger) to establish power contracts, regulate operating voltages, and detect the presence of foreign objects before battery charging starts. To this end, communications units 101f and 102f are used respectively at 101 and 102 power devices. The power signal provides the carrier for all communications.

The communications protocol differs between power profiles. The original protocol introduced in version 1.0 for BPP power profile consists of unidirectional communication from PRx to PTx. Starting from version 1.2, the Qi standard supports bidirectional communication.

To facilitate bidirectional communication, both Frequency Shift Keying (FSK) and Amplitude Shift Keying (ASK) are used. On the PTx side, communications to the PRx uses FSK modulation of the power transfer frequency. The PRx side modulates its load 102e to affect ASK communication to the PTx. Prior to Qi 2.0 version (BPP and EPP modes), FSK modulation speed at PTx is limited to 512 cycles per bit of data transferred while ASK modulation speed at PRx is limited to 128 cycles per bit of data transferred which is faster than FSK. In Qi 2.0 version, the PTx uses FSK modulation speed of 128 cycles per bit of data transferred in order to speed up the data streams at the PTx side.

The communications protocol has evolved within the Qi specifications to take account development of the power profiles. Version 1.3 has added an authentication process for a safer, consistent and reliable wireless power charging experience. The Qi version 2.0 has reduced the number of cycles per bit in order to speed up the data streams at PTx in particular for the authentication process.

The authentication units 101g and 102g support non-BPP power profiles (e.g. EPP and MPP) starting from version 1.3 for safer and reliable wireless power charging and to avoid PTx counterfeits. Referring to the Authentication protocol in version 1.3 and 2.0, two-step validation is required by validating the PTx certificate and a follow-up challenge to the PTx.

The memory in 101h and the memory in 102h may store the power devices respective data including certification data.

Either or both of the power transmitter 101 and the power receiver 102 may be implemented in a power charging device 1300 as shown in and described with reference to Figure 13 below.

We will now proceed to describe the Qi communications protocol for Qi-compliant devices with respect to Figures 2 and 3.

Figure 2 is a block schematic diagram of Qi communications protocol phases 200.

In Figure 2, four distinct phases for communication and power transfer between the transmitter and receiver are illustrated.

In the ping phase 201, the PTx, e.g. 101, monitors the charger dock surface for the placement or removal of an object. The PTx also may attempt to differentiate between a PRx, e.g. 102, and a foreign object. The PTx sends out a digital ping pulse and listens for a response to determine if a PRx is within range. If the PTx discovers a PRx, it then proceeds to the identification phase 202 and the configuration phase 203.

In the identification phase 202, the PTx identifies the selected PRx.

In the configuration phase 203, the PTx obtains configuration information such as the maximum allowed power to be transferred. The PTx uses this information to create a Power Transfer Contract (PTC) that contains limits for several power transfer parameters, also referred to as PTC parameters.

In the Power Transfer phase 204, the PTx provides power to the PRx, the PTx may constantly adjust its output based on control data from the PRx. During this phase, the PTx constantly monitors the PRx's PTC parameters and will terminate power transmission if it detects any of the PTC limits have been violated. The PTx will also terminate power transmission if the PRx device is removed during the Power Transfer phase 204, causing a time-out in the communications managed by the communication unit 101f.

According to a different power transfer mode (profile), such as EPP or MPP, a negotiation phase is implemented to initiate a change of power transfer mode (profile), to fine-tune the PTC, especially related to foreign object detection (FOD) parameters. To improve its initial assessment of whether foreign objects are present, the PTx compares the quality factor parameter reported by the PRx, with its own measurement.

Multiple power transfer modes (profiles) are part of the Qi specification. Each power transfer mode is named as a power profile, such as BPP, EPP or MPP. Baseline Power Profile, also referred to as BPP profile or BPP power profile, permits delivery of 5W maximum without authentication. Other profiles have been created to deliver more power and to extend compatibility between PTx and PRx. Enhanced Power Profile, also referred to as EPP profile or EPP power profile, permits delivery of 15W. In EPP, 15W is permitted by operating the inverter 101c in full-bridge inverter mode with resonant circuit 101d and primary coil 101e at 148Khz resonant frequency. Magnetic Power Profile, also referred to as MPP profile or MPP power profile, permits delivery of 15W by operating in full-bridge inverter mode PTx 101c with resonant circuit 101d and primary coil 101e at 360Khz resonant frequency. The alignment of primary coil 101z and secondary coil 102a is effective with +/-2mm of error. The wireless power transfer system 100 is able to change from BPP to any other profile such as EPP or MPP, by successively changing the resonant frequency, enabling bi-directional data communication, negotiating and renegotiating PTC, performing the authentication. All those changes may require multiple loops of one or more phases of the four communication protocol phases 200.

Figure 2 may be considered to represent a single loop of: -Three phases for MPP power profile including 201, 202 and 204 -Four complete phases including 201-204 for non-BPP power profiles.

This loop can be repeated as much as needed to reach full power delivery state, e.g. 15W maximum power transmission. In an example, the MPP power profile may need at least three loops to reach the full power delivery state.

Figure 3 is a block schematic diagram showing communications protocol operating mode for Qi-compliant devices.

According to Qi 2.0 communications protocol technical specification, clause 2.1, the communications protocol 200 comprises several phases, the four phases discussed previously, including ping 201, configuration 202, negotiation 203 and power transfer 204. The EPP and MPP power profiles include all the phases 201-203 in figure 2 except the BPP power profile where the negotiation phase 203 is skipped.

Before initiating a Digital Ping to solicit a response from a Power Receiver 102, the Power Transmitter 101 should go through the following stages.

Detect objects: For this purpose, the Power Transmitter can use Analog Pings 301 or a variety of alternative methods. The Qi, Power Delivery, Technical Specification provides a number of examples. The Analog ping 301 is a very low power signal for detecting an object without waking up the power receiver 101.

Collect information of the presence of any foreign object found in addition to the power receiver.

The PTx 101 detecting the placement of a PRx 102 on the charging surface, starts the Digital ping phase in 302 to wake up the PRx 102.

The digital ping phase 302 consists of sending a digital ping 302a by the PTx 101. The PRx 102 sends a signal strength SIG and then proceeds to the identification 302b and configuration in 303.

According to clause 5 in the Qi 2.0 communications protocol, the PRx may identify itself in 302b using an identification (ID) data packet and optionally an extended identification XID data packet. The identification allows the PTx to determine the supported Qi protocol version by reading the PRx's ID data packet. The XID data packet may advertise the support of either EPP or MPP power profiles. Based on the PRx identification data packets, the PTx shall proceed to the next phase according to the Qi specifications.

In the configuration phase 202 or 303, the Power Transmitter, e.g. PTx 101, and Power Receiver, e.g. PRx 102, continue to operate using the Digital Ping parameters. According to clause 5 in Qi 2.0 communications protocol, this part of the protocol in 303 consists of three sub-steps as follows: * The Power Receiver PRx identifies itself to the Power Transmitter PTx.

* The Power Receiver PRx and Power Transmitter PTx establish a baseline Power Transfer Contract.

* The Power Receiver PRx and Power Transmitter PTx determine the protocol variant to use in the power transfer.

The Negotiation phase 203 may come after the configuration phase 202 to negotiate the power contract elements. This phase is not present in the Baseline Protocol. In the case of EPP and MPP power profiles, the PTx 101 and the PRx 102 establish an extended or MPP power contract with additional settings.

The negotiation phase 203 may occur at two different stages in the communications protocol scheme. The negotiation phase 203 may be represented as question-answer technique where the PRx 102 sends simple query data packets and the PTx 101 answers with response pattern data packets. A first negotiation phase 304 may come directly after the configuration phase 202 or 303 serves to initiate the extended or MPP power contract by completing information about power loss accounting that is related to foreign object detection.

The length of the negotiation phase is not restricted. In addition to simple queries, the PTx can use data-request data packets to retrieve more information from the PTx, e.g., the PTx identification or the PTx capabilities or extended capabilities.

The negotiation may also come later as a renegotiation phase 306 that may interrupt occasionally the power transfer phase 204/305. It serves mainly to adjust the power contract elements that have been issued in a previous negotiation phase 304. It may also be used to create new power contract elements between the PTx and the PRx.

After negotiation phase 203/304 or renegotiation 306 in EPP/MPP or configuration phase 202/303 in BPP, the Power transfer phase 204/305 begins. This is the phase in which the power transfer to the Power Receiver's Load occurs. A calibration process is needed in this phase for EPP/MPP protocols. Occasional interruptions of this phase may occur to renegotiate an element in 304 of the Power Transfer Contract, i.e. renegotiation 306. However, the power transfer continues during such renegotiations.

In the power transfer phase 204/305, the PRx reports the received power level to the PTx. The PRx and the PTx aim to drive the control error data to zero, at which point the system is operating at its target power level.

The PTx and the PRx can exchange application-level data throughout the power transfer phase 204/305 by enabling data transport streams. An important common application is authentication 305a, where both sides can authenticate in order to validate their counterpart's credentials.

It is recommended that the PTx and PRx first negotiate a Power Transfer Contract in 304 for the low power level, and after successful authentication in 305a, subsequently renegotiate a Power Transfer Contract for the higher power level in 306. Following the Qi specifications for EPP/MPP or non-BPP power profiles, the power transmitter 101 and the power receiver 102 may transit between different protocol phases depicted in figure 2 multiple times. In an example, the power devices (101 and 102) may do a first ping 302, configuration 303, negotiation 304 and power transfer 305 phases. In 305, the devices may authenticate in 305a. After authentication validation, the PRx may need to renegotiate the power contract elements for higher power level. In this case, the power devices (101 and 102) may need to transit through the ping 302, configuration 303 phases to reach the renegotiation phase 306. After a successful renegotiation, the power devices (101 and 102) transit to the power transfer phase 305 to activate the full power delivery mode 305b as assigned in the renegotiated power contract.

The non-Baseline Power Profile communication protocol, particularly the Magnetic Power Profile communications protocol, will now be described in more detail with reference to Figures 4a and 4b.

Figures 4a and 4b illustrates an example of Magnetic Power Profile communications protocol for Qi-compliant devices.

Figure 4a is a block schematic diagram illustrating an example of non-Baseline Power Profile (BPP) communications protocol for Qi-compliant devices.

Figure 4b is a flow diagram showing an example of non-Baseline Power Profile (BPP) communications protocol for Qi-compliant devices.

Figures 4a and 4b are examples of establishment of non-BPP power charging mode between a power transmitter 101 and a power receiver 102. The figure 4a represents the block diagram wherein different flows may be exchanged between the power transmitter, e.g. PTx 101, and the power receiver, e.g. PRx 102, as further illustrated in figure 4b.

According to Qi specifications and to ensure backward compatibility, the system start up by operating initially in Qi BPP frequency band at 128 kHz to negotiate and determine which power profile is supported by both PTx and PRx devices. Therefore, the steps in 401, 402 and 403 reflect the ping 201, the configuration 202 and the power transfer 203 phases in BPP mode.

Referring to figure 2, the different consecutive phases constitute a loop. A BPP loop includes 201, 202 and 204 phases. A non-BPP loop include all phases 201-204.

After the power receiver PRx 102 wake up, it sends in digital ping 401 the signal strength SIG 401a and the identification 401b. As already stated, the identification may include the ID and the XID data packets of the PRx. The XID data packet helps the PTx 101 to determine the power profiles supported at the PRx side.

The PRx 102 may proceed by sending the configuration data packet (CFG) 402 in which the BPP power contract elements are settled. As the PTx 101 is aware of the supported power profiles at the PRx 102 side, it may send an FSK response pattern corresponding to an ACK response pattern (EPP mode) or MPP response pattern (M PP mode). Thus, the PRx identifies the supported power profiles at PTx side.

No negotiation phase is required in the BPP mode and thus, the power devices switch directly to the power transfer phase 403 and apply the BPP power contract established previously. Thus, a BPP mode may need one loop to begin power transfer at 5W.

In case both PRx and PTx support a non-BPP power profile (e.g., EPP or MPP or any further power profiles), the PRx may request a restart of the system in the power transfer phase 403. In order to establish a guaranteed load power level, the system may need several loops of four phases as stated above.

In an example, the PRx and the PTx may advertise MPP support. In the power transfer phase 403, the PRx may stop an on-going power transfer phase and request PTx to proceed for a new digital ping in order to activate the new operating frequency at 360 kHz proper for MPP devices. In details, PRx sends a message 'End of Power Transfer/ Re-Ping data packet, also named EPT/rep'.

A second digital ping 404 is executed at the new operating frequency including the flows 404a and 404b followed by a configuration 405 for MPP mode. According to the XID data packet in 404b, the PRx may select the MPP-restricted mode or the MPP full mode as the activated power profile. This may be considered the start of a second loop.

According to the Qi 2.0 communications MPP protocol technical specifications, the MPP restricted mode is a one-way directional communication from PRx to PTx with the power level limited to 5W as for the BPP mode. The MPP full mode is a bidirectional communication that enables all Qi communication protocol phases including the negotiation phase and allows power level transfer up to 15 W. In case of MPP restricted mode, the power devices (101 and 102), which may also be referred to a wireless power devices or wireless power transfer devices, perform a second configuration phase 405 followed by a power transfer phase 407. Hence, the transferred power level is 5 W at 360 kHz.

In case of MPP full mode, the configuration phase is followed by a first negotiation phase 406 where the PRx may send simple and data-request queries as stated earlier. As recommended by the Qi standard, a power transfer contract for power level (51/1/) may be negotiated first in 406. In this case, the second loop is considered as an intermediate loop for negotiating low power level in a non-BPP mode. Next, the power devices may start the power transfer phase in 407.

In 407, the power devices (101 and 102) may start an authentication process 408 in case the exchanged data streams are enabled. The authentication in 408 is a two-steps validation process. According to the Qi 2.0 authentication technical specifications, and as a first step validation process. According to the Qi 2.0 authentication technical specification, a first step of the validation process, the PRx 102 may request the Qi certification from the PTx 101 by sending a "Get Certificate" request 408a. The PTx 102 will send the certificate in "certificate chain" 408b if it exists. The certificate is a unique certificate pre-installed during the manufacturing process. The certificate chain has at least three certificates as stated in clause 3 of the Qi 2.0 authentication technical specification: * Root certificate identifying the WPC Root Certificate Authority; * Manufacturer CA certificate identifying the product's manufacturer; and * Product certificate identifying the individual power transmitted product.

The root and manufacturer certificates are signed by the WPC Root certificate Authority. The certificate chain length is of the order of hundreds of bytes. For MPP, for example, the certificate chain may exceed the 512 bytes as mentioned in clause 8.6.2.4.

The PRx once receiving the certificate chain may proceed to the validation. In addition to the validation of the certificate, the PRx will send a follow-up "Challenge" 408c to the PTx as a second step validation process. The PTx may reply with "Challenge response" 408d signed with the PTx's unique private key.

The PRx may initiate the operations in any order by challenging the PTx first and then requesting the certificate chain.

Upon successful two-step authentication validation, the power devices need to renegotiate the power transfer contract to bring power level at a new guaranteed load power level above 5 W. Thus, the system may transit again through the different phases in 409 to reach the renegotiation phase 306 or 410, that is to say that the system may start a third loop.

Once power transfer contract is issued, the power devices (101 and 102) transit to the power transfer phase 411 and activate the full power delivery mode 411a above 5W. In case of failed authentication process, the PRx can choose not to draw power levels above 5W.

The certificate chain length is of the order of hundreds of bytes and can exceed 512 bytes for MPP mode. The in-band communications between power devices, e.g. PRx and PTx, have low data rate estimated to 2 kbits/sec. Hence, 512 bytes of certificate may need a few seconds to be transferred successfully.

In order to reduce the time required for authentication process, the PRx may use the "Get Digest" request for faster validation process. The PTx may reply with the Digest response. The Digest method can be used just if the digest is cached at PRx.

If the Digest is not in cache, the PRx will be obliged to go through the full authentication process to activate the full power delivery mode. Some user experiences may suffer from this latency as the authentication process as stated is time consuming and redundant. In a first example of user experience, a power receiver is on wireless power charger (i.e. wireless power transmitter) and is unplugged (i.e. moved out of range or similar) for a spontaneous usage and then plugged (i.e. moved within range or similar) again. Thus, the power devices need to go through all the authentication process if digest is not in the cache. In a second example of user experience, the power transmitter may be for personal use and thus, it is a trusted or reliable device for the PRx. After a first successful authentication, the power transmitter can be considered as trusted or reliable device and thus, the authentication process is a waste of time.

Furthermore, future Qi generations focusing on fast charging requirements. A heavy authentication process, e.g. one which is time consuming, as in the present specifications may not be aligned with the Qi standard requirements. Therefore, the communications protocol with a heavy authentication process suffers from high latency and low responsiveness.

In order to respond to user experiences and future Qi generations requirements, there is a need to optimize the authentication process.

Figure 5 illustrates data packet structure as specified in the communications protocol operating mode for Qi-compliant devices.

The PTx, e.g. 101, and PRx, e.g. 102, communicate using data packets. A data packet 550 consists of a series of bytes that the PTx or PRx sends as a contiguous sequence. The data packet 550 comprises three parts, a header 551, a message 552, and a checksum 553.

The header 551 comprises a single byte that indicates the data packet type. In addition, the header implicitly provides the size of the message 522 contained in the data packet. The number of bytes in the message 552 is calculated from the value contained in the header 551 of the data packet 550 as described in Qi specification v2.0. The checksum 553 comprises a single byte equal to an XOR operation of all bytes from header byte value and message bytes value. The header, message, and checksum consist of a sequence of three or more bytes. Figures 6a, 6b, 6c and 6d illustrate identification messages used during PTx and PRx identifier exchange as specified in the communications protocol operating mode for Qicompliant devices.

Figure 6a illustrates basic identification message 630 as specified in the communications protocol operating mode considering BPP for Qi-compliant devices.

The basic identification message for either the PRx or PTx is composed of 7 bytes. This message can be exchanged during BPP profile. The fields Major version 632 and Minor version 631 are used to indicate the Qi standard version supported by the device, for example Qi standard 1.0, Qi standard 1.3 or Qi standard 2.0 etc. The field Ext 635 is used to indicate that an additional message will be sent to exchange additional properties of the device. The field Manufacturer code 633 is used to indicate a registered code in the Wireless Power Consortium referencing the manufacturer of the device. The field Basic Device Identifier 634, also referred to as the Basic Identifier, in combination with the Manufacturer Code, enables a multi-coil Power Transmitter to recognize the PRx within a set of PRx(s) present in its Operating Volume. To enable such recognition, the Basic Device Identifier should comprise a 20-bit serial number. To preserve user privacy, the PRx may dynamically generate the Basic Identifier to have randomly generated values. However, if the PRx generates this identifier dynamically, it shall not change it within two seconds after losing the Power Signal. That is to say that if the PRx generated the Basic Identifier dynamically, it will maintain the same generated Basic Identifier for a two second period after losing the Power Signal.

In one embodiment of the disclosure, the field Basic Device Identifier 634 can be set to a value used during a previous power transfer experience. That is to say that the Basic Device Identifier 634 may be set to a previous value used during a previous power transfer experience between the same PRx and PTX. By receiving the message 630 including this previous set Basic Device Identifier value, a first device can identify a second device as a device previously used during a previous power transfer experience. Consequently, the first device can initiate the previously established power profile used during the said previous power transfer experience. That is to say that the first device can establish one or more power transfer settings associated with the previous power profile used with the second device. Also, one device of the first or second devices can generate an alert to notify an end user that a previous power profile is established or will be established. The corresponding alert can inform the end user of which power profile is established or will be established using a pop-up message or an animation on screen.

Figure 6b illustrates PRx identification message as specified in the communications protocol operating mode considering M PP for Qi-compliant devices.

The PRx identification message 600 is composed of 4 bytes. The fields Selector 603 and Report 604 are used to indicate the type of message, which is PRx report identification. The fields Rsvd' 602a, 602b and 602c are reserved fields for proprietary custom message and/or future evolution. By default, their values are 0. The field Identifier 601 contains a random value generated by PRx during a power transfer experience. To preserve user privacy, the Power Receiver PRx may dynamically generate the Identifier 601.

In one embodiment of the disclosure, the field Identifier 601 can be set to a value used during a previous power transfer experience. That is to say that the PRx may set the value of the field Identifier 601 to be a value that was previously used, i.e. a previously generated random value, during a previous power transfer experience. By receiving the message 600 including a previously used value for the Identifier 601 field, a PTx can identify a PRx as a device used during a previous power transfer experience. Consequently, the PRx and/or PTx can initiate the previously established power profile used during the said previous power transfer experience. Also, one device of the PRx or PTx can generate an alert to notify an end user that a previous power profile is established or will be established. The corresponding alert can inform the end user of which power profile is established or will be established using a pop-up message or an animation on screen.

In one embodiment of the disclosure, one or more of the fields Rsvd' 602a, 602b and 602c may be used to indicate that the PRx is requesting PTx to recover a power profile used during a previous power transfer experience. For example, bit b0 of byte BO can be set to 1 to indicate this request. Any other 'Rsvd' field may be used.

Figure 6c illustrates PRx identification message to request PTx to exchange PTx identification message as specified in the communications protocol operating mode considering MPP for Qi-compliant devices.

The PRx GET PTx identification message 610 is composed of 2 bytes. The field Selector 613 is used to indicate the type of message, which is PRx Get PTx identification. The fields Rsvd' 612a, and 612b are reserved fields for proprietary custom message and/or future evolution. By default, their values are 0. The PRx sends the message 610 to PTx to request the PTx identifier. The PTx answers with message 620 including the PTx identifier. Message 620 is shown in figure 6d and discussed in detail below.

In one embodiment of the disclosure, one or more of the fields Rsvd' 612a and 612b may be used to indicate that the PRx is requesting PTx to recover a power profile used during a previous power transfer experience. For example, bit b0 of byte BO can be set to 1 to indicate this request. Any other 'Rsvd' field 612a and 612b may be similarly used.

Figure 6d illustrates PTx identification message as specified in the communications protocol operating mode considering MPP for Qi-compliant devices.

The PTx identification message 620 is composed of 8 bytes. The field Selector 623 is used to indicate the type of message, which is Extended PTx identification. The message 620 is sent by PTx to respond to PRx request using message 610. The fields 'Rsvd' 622a, 622b, 622c, 622d and 622e are reserved fields for proprietary custom message and/or future evolution. By default, their values are 0. The PTx sends the message 620 to PRx which includes the PTx identifier as requested by the message 610.

In one embodiment of the disclosure, one or more of the fields Rsvd' 622a, 622b, 622c, 622d and 622e may be used to indicate that the PTx identifier 621 value was used during a previous power transfer. That is to say that the PTx may set the value of one or more of the 'Rsvd' fields to indicate that PTx identifier 621 in the message is a value that was previously used, i.e. a previously generated random value, during a previous power transfer experience For example, bit b0 of byte B0 can be set to 1 to indicate this property. Any other Rsvd' field 622a, 622b, 622c, 622d and 622e may be similarly used.

Figure 7 is a flowchart illustrating the exchange of identification messages between PRx and PTx as specified in the communications protocol operating mode considering MPP for Qi-compliant devices.

In the flowchart 700, The exchange of identification messages 704, 714 and 715 are illustrated between PRx and PTx.

At first, PRx send message 704 to PTx to report PRx identifier during a digital ping 701. Other messages such a 702 and 703 may also be sent during the same phase. During phase 711, which can be a negotiation phase, renegotiation phase or a power transfer phase, such as those discussed above, PRx sends message 714 to PTx to get PTx identifier. PTx responds with a message 715.

The message 704 corresponds to the definition of message format 600. That is to say that message 704 may be message 600 discussed above.

The message 714 corresponds to the definition of message format 610. That is to say that message 714 may be message 610 discussed above.

The message 715 corresponds to the definition of message format 620. That is to say that message 715 may be message 620 discussed above.

Figure 8 illustrates an example format of memorized data information during one or more previous power transfer experiences by a device in accordance with embodiments of the present disclosure. That is to say an example format of data information stored in a memory, the data information being established during one or more previous power transfer experiences by a device, such as a device in accordance with one or more embodiments of the present disclosure.

Format 800, represented as a table in Figure 8, of the memorized data information during one or more previous power transfer experiences may comprise multiple inputs ordered using an index number 810 for each memorized experience 801,802 or 803. That is to say that each set of data information associated with a previous power transfer experience, i.e. data information for each memorized power transfer experience, may be stored in an ordered way, preferably by using a field such as index number 810 with each set of data information being associated to an index value 801, 802, 803.

A memorized power transfer experience, 801, 802 and 803, comprises a structure including PRx identifiers 811 or PTx identifiers 812 or both. Additionally, each memorized power transfer experience may include the power profile 813 used during the corresponding power transfer experience. That is to say that the data information for each memorized power transfer experience comprises at least one of a PRx identifier 811 and a PTx 812 identifier.

The data information for each memorized power transfer experience may comprise the power profile 813 used for the corresponding power transfer experience. The data information is stored in association with the index number in respective fields, taking the example shown in figure 8, PRx identifier '0x12EDE', PTx identifier '0x317A6', Profile 'MPP', Cached data 'chain certificate ' and Timestamp '1691624800' are stored in association with index number '1' in respective fields of the table. Each index number 801, 802, 803, etc are memorized power transfer experiences.

The memorized power profile 813 may be used to recover the previously establish power transfer profile and to alert end user the power transfer profile which is established.

The memorized data information may include the chain certificate 814 used during the corresponding power transfer experience. The memorized certificate chain 814 may be used to recover the previously establish power transfer profile and to optimize the authentication process by using a fast method as described in figure 4b.

The memorized data information may include a timestamp 815 indicating the absolute time the corresponding power transfer experience was completed. The memorized timestamp 815 can be used to order the different memorized experiences. Using the memorized timestamp 815, PRx or PTx can recover the most recent previously establish power transfer profile. The memorized timestamp 815 format can be Unix time. It measures time by the number of non-leap seconds that have elapsed since 00:00:00 UTC on 1 January 1970, the Unix epoch.

Figure 9 illustrates, using a flowchart, steps of a method to recover a power transfer phase from a previous experience according to embodiments of the disclosure.

In step 901, PTx or PRx performs an identification as described in Figure 7. According to the identification message(s) exchanged, PTx or PRx searches a previous power transfer experience in the memorized data information as illustrated in Figure 8.

In one embodiment, the PTx or PRx can use an identifier value already used during a previous power transfer experience to implicitly request the other one of the PRx or PTx to recognize the sender as a device being involved in the said previous power transfer experience.

In another embodiment, the PTx or PRx may use a reserved field in message(s) as described above to explicitly request the other one of the PRx or PTx to deliver an identifier value already used during a previous power transfer experience. In another embodiment, the PTx or PRx may use a reserved field in message(s) as described above to explicitly indicate to the other one of the PRx or PTx that the identifier value was already used during a previous power transfer experience. The identifier value can be time-invariant.

In step 902, the PTx or PRx may proceed towards power transfer based on a power transfer profile from the memorized data information if the identification, in step 901, permits to find a previous power transfer experience in the memorized data information as illustrated in Figure 8.

Figure 10 illustrates, using a flowchart, steps of a method to recover a power transfer phase from a previous experience according to one or more embodiments of the disclosure.

Figure 10a illustrates, using a flowchart, steps of a method performed by a PRx to recover a power transfer phase from a previous experience according to embodiments of the invention.

In step 1001, a PRx determines a PRx identifier value. If the memorized data information is empty, the PRx generates a random value. Otherwise, the PRx selects one from the memorized power transfer experiences from 800. For example, the PRX select the PRx identifier 811 of most recent power transfer experience by using the most recent timestamp value 815. For example, using the data information shown in figure 8, the PRx may select memorized power transfer experience 802.

In step 1002, the PRx transmits to a PTx a message 704 including the determined PRx identifier.

In step 1003, the PRx receives from the PTx a message 715 including a second identifier.

The second identifier being the PTx identifier, which may be a dynamically generated one, i.e. a random value, or as explained later one from memorized data information.

In step 1004, the PRx determines if the second identifier corresponds to the selected memorized power transfer experiences in step 1001.

In step 1005, if the second identifier corresponds to the selected memorized power transfer experience in step 1001, the PRx proceeds with the power transfer profile 813 of the selected memorized power transfer experience. For example, using the data information in figure 8, the PRx compares the received second identifier to the value in the PTx identifier 812 of memorized power transfer experience 802 and if it matches, the PRx proceed with the power transfer profile MPP.

In step 1005, the PRx can proceed to recover the power transfer profile as described in Figure 12.

The PRx may memorize a new power transfer experience or updated an existing one. For example, the new power transfer experience may be a new entry which comprises all the same data information but with a different timestamp. In another example, the timestamp filed of the power transfer experience with matching PRx identifier and PTx identifier is updated with a new timestamp. In another example, a PRx may change it PRx identifier for privacy reason using identification message as described in Figure 6. In this case, the used entry is removed and replaced by the new power transfer experience including the new PRx identifier. It permits to maintain PRx privacy by renewing PRx identifier.

In step 1004, if the second identifier doesn't correspond to the selected memorized power transfer experience in step 1001, the PRx can return in step 1001 and select another memorized power transfer experience. If there are no other memorized power transfer experiences, PRx can proceed as described in Figure 4, i.e. it proceeds through the normal communication loops.

Figure 10b illustrates, using a flowchart, steps of a method to recover by the PTx a power transfer phase from a previous experience according to one or more embodiments of the disclosure.

In step 1011, the PTx receives from the PRx a first identifier. The first identifier being a PRx identifier which may be a dynamically generated one, i.e. a random value, or as explained above one from memorized data information.

In step 1012, the PTx determines if the first identifier value corresponds to the one of the PRx identifier values in the memorized data information of previous power transfer experiences.

If the first identifier value is found in the memorized data information, the PTx transmits to the PRx an identification message including an identifier value from the previously determined power transfer experience. Put another way, if the received first identifier is found in the PRx identifier field 811 of the memorized data information, the PTx will send the value in the corresponding PTx identifier field 812 of the memorized power transfer experience. For example, if the received first identifier is OxACDF0', the PTx will find it in field 811 in association with memorized power transfer experience 802 and send the value (0x32950' in the corresponding PTx identifier field 812.

Otherwise, if the first identifier does not match a memorized PRx identifier 811, the PTx transmits identification message with a random identifier value.

Figure 11 illustrates, using a flowchart, steps of a method to recover a power transfer phase from a previous power transfer experience according to one or more embodiments of the disclosure.

Figure lla illustrates, using a flowchart, steps of a method to recover by a PRx a power transfer phase from a previous power transfer experience according to one or more embodiments of the disclosure; In step 1101, the PRx transmits to the PTx a request to recover a power transfer profile according to a previous power transfer experience.

In one embodiment, the PRx can use a message 600 and an indication using a bit value equal to 1 in one of the reserved fields 602a, 602b or 602c to explicitly request the PTx to respond with an identifier either determined from a memorized previous experience in the PTx memorized data information.

In another embodiment, the PRx can use a message 600 and an indication using a bit value equal to 1 in one of the reserved fields 602a, 602b or 602c to explicitly request the PTx to respond with an identifier being time invariant.

In another embodiment, the PRx can use a message 610 and an indication using a bit value equal to 1 in one of the reserved fields 612a or 612b to explicitly request the PTx to respond with an identifier determined from a memorized previous experience in the PTx memorized data information.

In another embodiment, the PRx can use a message 610 and an indication using a bit value equal to 1 in one of the reserved fields 612a or 612b to explicitly request the PTx to respond with an identifier being time invariant.

In step 1102, the PRx receives from the PTx message 715 including a PTx identifier.

In step 1103, the PRx determines if the received PTx identifier value corresponds to one of the memorized power transfer experiences of the PRx.

In step 1104, if the received PTx identifier value corresponds to one of the memorized power transfer experiences of the PRx, the PRx proceeds with the power transfer profile 813 of the determined memorized power transfer experience. The PRx can proceed to recover the power transfer profile as described in Figure 12.

The PRx memorizes a new power transfer experience or updates an existing one. For example, the new power transfer experience may be a new entry which comprises all the same data information but with a different timestamp. In another example, the timestamp filed of the power transfer experience determined to comprise the matching PRx identifier and PTx identifier is updated with a new timestamp.

Figure 11 b illustrates, using a flowchart, steps of a method to recover by PTx a power transfer phase from a previous experience according to an embodiment of the disclosure.

In step 1111, the PTx receives from the PRx a request to recover a power transfer profile according to a previous power transfer experience.

In step 1112, the Fix transmits an indication and an identifier to the PRx. The indicator indicating that the identifier is from a memorized power transfer or is a time invariant value.

In one embodiment, the PTx transmits a message 620 with an identifier value of one of the memorized power transfer experiences of the PTx.

In another embodiment, PTx transmits a message 620 with an identifier value being time invariant.

In another embodiment, the PTx transmits a message 620 with an identifier value equal to an identifier value from a previously received identification message from a PRx.

In one embodiment, the PTx may use a message 620 and an indication using a bit value equal to 1 in one of the reserved fields 622a, 622b, 622c or 612d to explicitly respond to the PRx with an identifier either determined from the memorized previous experience in PTx memorized data information or being time invariant.

Figure 12 is a flow diagram showing an example of Magnetic Power Profile (MPP) communications protocol for Qi-compliant devices according to one or more embodiments of the disclosure.

The flow diagram 1200 illustrates an example of the establishment of a power charging mode between a power transmitter, PTx, 101 and a power receiver, PRx, 102 according to the disclosure.

According to Qi specifications and to ensure backward compatibility, the system start up by operating initially in Qi BPP frequency band at 128 kHz.

After the power receiver 102 wakes up, PRx and PTx proceeds to Digital Ping 1201, corresponding to 401 discussed above, configuration, corresponding to 402 discussed above, and power transfer phase 1203, corresponding to 403 discussed above.

The PRx may request a restart of the system in the power transfer phase 403.

The PRx and the PTx advertise MPP support. In 1203, the PRx may send then an EPT/rep data packet, as described in relation to Figure 4, in order to activate the new operating frequency at 360 kHz proper for MPP devices.

In some embodiments, the Qi standard authentication process may be omitted entirely or some steps may be omitted during the further power delivery experience because the authentication has been performed previously during a previous power delivery experience. For example, there is no need to send a GET message to request the certificate from the wireless power transmitter. In some embodiments, the power receiver may rely on the previous authentication with the certificate chain it has memorized for that particular power delivery experience or it may partially relay on the certificate chain and challenge the power transmitter.

A second digital ping 1204 is executed at the new operating frequency including the flows 404a and 404b followed by a configuration 1205 for MPP mode. According to the disclosure, the identification phase proceeds as described above, particularly but not exclusively as described above and shown in Figures 9, 10, 11 or 12, during digital ping 1204 and negotiation 1206. In step 1250, the PRx or the PTx determines if a memorized power transfer experience have been found, for example as described in reference to 901, 1004 or 1012. If a memorized power transfer experience has been found, for example as described in reference to 901, 1004 or 1012, the PRx or the PTx proceeds to 1215 to establish a power transfer profile using the corresponding memorized data information as described in reference to and shown in Figure 8.

If a memorized power transfer experience has not been found in 1250, the PRx or the PTx may determine in step 1251 if another memorized power transfer experience may be used to recover a power transfer profile. If another memorized power transfer experience may be used, e.g. there are additional memorized power transfer experiences, the PRx and the PTx proceeds with another iteration of digital ping 1204 using the determined power transfer experience in 1251.

Otherwise, if it is determined that another memorized power transfer experience may not be used, e.g. there is no other memorized power transfer experience, the PRx and the PTx proceeds through the normal course of establishing a non-BPP power profile, for example as described in reference to Figure 4. The PRx and the PTx proceed for multiple iterations of digital ping (1207, 1211), configuration (1208,1212), negotiation 1209, renegotiation 1213 and power transfer phases (1210, 1214). As is the case in Figure 4, the authentication 1210a is performed during a power transfer phase 1210 before the full power delivery 1214a can be established in power transfer phase 1214 after renegotiation 1213.

According to the disclosure, in 1252, the established power transfer is memorized as a power transfer experience as described above, e.g. in reference to Figure 8.

In 1215, the PRx or the PTx start to proceed with power transfer profile recovery using the profile determined in 1250. In step 1215, the PRx and the PTx proceeds keeping in consideration that a profile is determined and will be configured according to the disclosure.

In one embodiment, the PRx and the PTx can generate new identifiers using random values to keep privacy and use them during digital ping 1215 and renegotiation 1217.

In another embodiment, the PTx may keep an identifier value for future power transfer experience. In such a case, the identifier is a time invariant identifier, i.e. the identifier does not change dynamically.

In another embodiment, the PRx and the PTx may keep identifier values for a limited number of times of future power transfer experiences. That is to say that the PRx and the PTx may keep the identifier values for a limited period. The limited period either being time based or based on a number of power transfer experiences.

After renegotiation 1217, a power transfer phase 1218 or 1219 is established.

In one embodiment, the full power delivery 1218a may be established before authentication 1219a.

In another embodiment, the authentication may be optimized using the memorized certificate chain 815 in the memorized data information 800 before or after the full power delivery 1218a. In effect the PTx has been pre-authorised because authorisation was successful previously. In some embodiments, a limited form of authorisation may proceed before or after the full power delivery, for example by not requiring full transmission of the certificate.

Finally, the memorized data information 800 is updated as described in Figure 8. Figure 13 is a block schematic diagram of an example of a wireless charging device according to one or more embodiments of the present disclosure.

The wireless charging device 1300 may preferably be an electronic device capable of wireless charging such as a micro-computer or a workstation or a mobile device or a light portable device or a fixed device. The wireless charging device 1300 comprises a communication bus 1313 to which there are preferably connected: -a processing unit 1311, such as a microprocessor, and denoted CPU in Figure 13. The processing unit 1311 may be a single processing unit or processor or may comprise two or more processing units or processors carrying out the processing required for the operation of the wireless charging device 1300. The number of processors and the allocation of processing functions to the central processing unit 1311 is a matter of design choice for a skilled person; -memory for storing data and one or more computer programs containing instructions for the operation of the communication device 1300. The computer programs may contain a number of different program elements (modules) or sub-routines containing instructions for a variety of operations and for implementing the methods of one or more embodiments of the disclosure; and -at least one communication interface 1302 for communicating with other devices or nodes in a wireless communication system, such as the wireless charging system of Figure 1.

The at least one communication interface 1302 may be connected to a second communication interface 1303, such as a secondary coil or RFID of the wireless charging system, over which digital data packets or frames or control frames are transmitted.

Each of the power transmitter, PTx, and the power receiver, PRx, may comprise such a wireless charging device 1300.

The memory may include: - a read only memory 1307, denoted ROM, for storing computer programs and instructions for implementing the methods of one or more embodiments of the disclosure; -a random-access memory 1312, denoted RAM, for storing the executable code of the methods of one or more embodiments of the disclosure. The RAM may also store the registers adapted to record variables and parameters necessary for implementing the methods of one

or more embodiments of the disclosure.

Optionally, the communication device 1300 may also include one or more of the following components: - a data storage means 1304 such as a hard disk, for storing computer programs and instructions for implementing the methods of one or more embodiments of the disclosure; -a disk drive 1305 for a disk 1306, the disk drive being adapted to read data from the disk 1306 or to write data onto said disk; - a screen 1309 for displaying decoded data and/or serving as a graphical interface with the user, by means of a keyboard 1310 or any other user input means.

Preferably the communication bus provides communication and interoperability between the various elements included in the communication device 1300 or connected to it. The representation of the bus is not limiting and in particular, the processing unit is operable to communicate instructions to any element of the wireless charging device 1300 directly or by means of another element of the wireless charging device 1300.

The disk 1306 may optionally be replaced by any information medium such as for example a compact disk (CD-ROM), rewritable or not, a ZIP disk, a USB key or a memory card and, in general terms, by an information storage means that can be read by a microcomputer or by a microprocessor, integrated or not into the communication device, possibly removable and adapted to store one or more programs whose execution enables methods according to embodiments of the disclosure to be implemented.

The executable code may optionally be stored either in read only memory 1307, on the hard disk 1304 or on a removable digital medium such as for example a disk 1306 as described previously. According to an optional variant, the executable code of the programs can be received by means of the communication interface 1303, via the interface 1302, in order to be stored in one of the storage means of the communication device 1300, such as the hard disk 1304, before being executed.

The processing unit 1311 is preferably adapted to control and direct the execution of the instructions or portions of software code of the program or programs according to the invention, which instructions are stored in one of the aforementioned storage means. Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry.

Accordingly, the term "processor," as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. Also, the techniques could be fully implemented in one or more circuits or logic elements.

Figure 14 illustrates, using a flowchart, steps of a method to record a power transfer from a previous power delivery experience.

In step 1401, information for use in identifying whether power delivery (transfer) experience has occurred previously between a first wireless power device, i.e. the power transmitter, PTx, and a second wireless power device, i.e. the power receiver, PRx. That is to say that information for use in identifying whether the first wireless power device and second wireless power device have had an experience in which one delivered power to the other is received by one or more of the first and second wireless power apparatuses.

In step 1402, it is determined whether or not to establish a further power delivery between the first and second wireless power apparatuses. The determination is based on if a previous power delivery experience has occurred between the first and second wireless apparatuses. That is to say, in the case where it is identified that a power delivery did previously occur between the first and second wireless apparatuses, a further power delivery is established between the two apparatuses.

Steps 1403 and 1404 are preferable steps and indicated in dashed lines.

In step 1403, the apparatus receiving the information, either the first and/or second wireless power apparatus, will check information stored in or accessible from the first and/or second wireless power apparatuses. This check may be as discussed above, i.e. compare the memorized information to the received information. Based on the check step, the apparatus is able to determine whether power delivery was previously performed between the devices. In step 1404, the apparatus receiving the information uses the stored information to determine what power profile was used in the power delivery previously performed. i.e. the apparatus is able to look at the memorized information to determine what power profile was used between the two apparatuses. The power profile of the previously performed power delivery is used for the further power delivery.

While the present disclosure has been described with reference to embodiments, it is to be understood that the disclosure is not limited to only the disclosed embodiments. It will be appreciated by those skilled in the art that various changes and modification might be made without departing from the scope of the disclosure, as understood by the appended claims or by the disclosure as a whole. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be advantageously used.

In the preceding embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over, as one or more instructions or code, a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. In this manner, computer-readable media generally may correspond to (1) tangible computer-readable storage media which is non-transitory or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium.

By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but are instead directed to non-transient, tangible storage media. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

Improvements of communications protocol are illustrated in the following figures to answer user experience requirements in accordance with one or more embodiments of the invention.

For the sake of simplicity, the term "power transfer experience" designates a user experience with a PRx and PTx where the full power delivery mode, e.g. 15W in MPP, is activated, preferably with a successful authentication. Equivalently, this may be referred to as a power transfer session' or 'a previously performed power transfer, 'power delivery, 'power delivery experience', or similar.

The term "first user experience" designates a user experience where the full power delivery mode is activated after successful authentication. Equivalently, this can be referred to as a first power transfer session between a power transmitter and power received in a full power deliver mode. It is considered for the power devices as the reference user experience to be used to establish specific settings (i.e. settings that relate specifically to the first user experience or first power transfer session in the full power delivery mode). The term "first user experience" is used in the rest of the description.

Claims (56)

1. CLAIMS1. A method for managing wireless power delivery between a first wireless power apparatus to a second wireless power apparatus, the method comprising: receiving information for use in identifying whether a power delivery was previously performed between the first and second wireless power apparatuses; and in the case where the information identifies that power delivery was previously performed between the first and second wireless power apparatuses, establish a further power delivery between the first and second wireless power apparatuses based on the power delivery previously performed between the first and second wireless power apparatuses.
2. 2. A method according to claim 1, wherein a power delivery comprises at least one power profile, and wherein the power profile of further power delivery is based on the at least one power profile of the previously performed power delivery.
3. 3. A method according to claim 2, wherein the power profile of the further power delivery is the same as a power profile of the at least one power profile of the previously performed power delivery.
4. 4. A method according to claim 2 or claim 3, wherein the at least one power profile of the previously performed power delivery is a full or high power delivery mode, and wherein the power profile of the further power delivery is a full or high power delivery mode.
5. 5. A method according to any one of claims 2 to 4, wherein the power profile of the previously performed power delivery is a non-Baseline Power Profile, non-NPP, and wherein the recovered power profile is a non-Baseline Power Profile.
6. 6. A method according to any one of claims 2 to 5, wherein the non-BPP profiles are an extended power profile, EPP, or a magnetic power profile, MPP.
7. 7. A method according to any one of claims 2 to 6, wherein the power profile of the previously performed power delivery and the power profile of the further power delivery are the same power profile.
8. 8. A method according to any preceding claim, wherein information for use in identifying whether the power delivery was previously performed comprises apparatus identification information, the apparatus identification information being an identifier of at least one of the first wireless power apparatus and the second wireless power apparatus.
9. 9. A method according to claim 8, wherein identification information is associated with the second wireless power apparatus.
10. 10. A method according to any preceding claim, wherein further information for use in identifying whether a power delivery was previously performed comprises further identification information, the further identification information being an identifier of at least one of the first wireless power apparatus and the second wireless power apparatus.
11. 11. A method according to claim 10, wherein the further identification information is associated with the first wireless power apparatus.
12. 12. A method according to any one of claims 8 to 11, wherein identification information for use in identifying whether the power delivery was previously performed is from a previously performed power delivery.
13. 13. A method according to claim 12, wherein the identification information for use in identifying whether the power delivery was previously performed was generated during establishment of a previously performed power delivery.
14. 14. A method according to claim 12 18 or claiml3 19, wherein the identification information generated during previously performed power delivery comprises a dynamic value used for identifying the wireless power apparatuses.
15. 15. A method according to any one of claims 12 to 14, wherein the identification information generated during previously performed power delivery comprises a random value.
16. 16. A method according to any preceding claim, wherein identification information comprises a fixed value.
17. 17. A method according to claim 16, wherein the first wireless power apparatus comprises the fixed value.
18. 18. A method according to any preceding claim, wherein identification information generated during previously performed power delivery between first and second wireless power apparatuses are stored in both the first wireless power apparatus and the second wireless power apparatus.
19. 19. A method according to any preceding claim, wherein the information for use in identifying whether the power delivery was previously performed comprises indicator information for indicating a request for identification information or for indicating intention for a further power delivery to be established based on a previously performed power delivery or for indicating whether information from a power delivery previously performed is present.
20. 20. A method according to any preceding claim, wherein at least one of the first wireless power apparatus and the second wireless power apparatus comprise a memory for storing information associated with at least the other of the first or second wireless power apparatus, wherein the information stored is associated to a power delivery previously performed.
21. 21. A method according to claim 20, wherein the stored information comprises information for use in identifying whether the power delivery was previously performed between first and second wireless power apparatuses.
22. 22. A method according to claim 20 or claim 21, wherein the stored information comprises a first identifier for identification information of the first wireless power apparatus and a second identifier for identification information of the second wireless power apparatus, the identifiers being stored in a relationship indicating a previously performed power delivery.
23. 23. A method according to any one of claims 20 to 22, wherein the stored information comprises information for identifying a power delivery mode used for the power delivery previously performed, the information being stored in a relationship with the first and second identifiers.
24. 24. A method according to claim 23, wherein the information for identifying the power delivery mode indicates a non-Baseline Power Profile mode.
25. 25. A method according to any one of claims 20 to 24, wherein the stored information comprises information associated with an authentication process performed between the first and second wireless power apparatuses during establishment of the previously performed power delivery, the information being stored in a relationship with the first and second identifiers.
26. 26. A method according to claim 25, wherein the information associated with an authentication process comprises certificate information.
27. 27. A method according to any one of claims 20 to 26, wherein the stored information comprises information for identifying a time of the previously performed power delivery, the information being stored in a relationship with the first and second identifiers.
28. 28. A method according to claim 27, wherein the information for identifying a time is timestamp information.
29. 29. A method according to any one of claims 20 to 28, wherein the stored information is indexed in a relationship indicating a previously performed power delivery.
30. 30. A method according to any preceding claim, wherein the first wireless power apparatus receives information for use in identifying whether the power delivery was previously performed between the first and second wireless power apparatuses.
31. 31. A method according to claim 30, further comprising checking, by the first wireless power apparatus, information stored in the first wireless power apparatus based on the received information, the information stored in the first wireless power apparatus comprising information associated with previously performed power deliveries.
32. 32. A method according to claim 31, further comprising sending, by the first wireless power apparatus, further information for identifying whether a power delivery was previously performed between the first and second power apparatuses, the further information comprising information associated with the previously performed power delivery from the stored information.
33. 33. A method according to claim 32, wherein the received information comprises a request for the further information.
34. 34. A method according to claim 32 or claim 33, wherein sending the further information is performed in the case where checking identifies previously performed power deliveries based on the received information.
35. 35. A method according to any preceding claim, wherein the second wireless power apparatus receives information for use in identifying whether power delivery was previously performed.
36. 36. A method according to claim 35, when dependent upon any one of claims 31 to 34, wherein the information received by the second wireless power apparatus is further information from the first wireless power apparatus.
37. 37. A method according to claim 35 or claim 36, further comprising checking, by the second wireless power apparatus, information stored in the second wireless power apparatus based on the received information, the information stored in the second wireless power apparatus comprising information associated with previously performed power deliveries.
38. 38. A method according to claim 37, wherein, in the case where a previously performed power delivery between the first wireless power device and the second wireless power device based on the received information has been identified, establishing the further power delivery based on the information stored in the second wireless power apparatus associated with the identified previously performed power delivery.
39. 39. A method according to any preceding claim, further comprising sending, by the second wireless power apparatus, information for use in identifying whether power delivery was previously performed between the first and second wireless power apparatuses.
40. 40. A method according to claim 39, wherein sending, by the wireless power apparatus, information comprises an indication for requesting information for use in identifying whether power delivery was previously performed between the first and second wireless power apparatuses.
41. 41. A method according to claim 39, wherein the information for use in identifying whether power delivery was previously performed between the first and second wireless power apparatus sent by the second wireless power apparatus is information stored in the second wireless apparatus associated with previously performed power deliveries.
42. 42. A method according to any preceding claim, wherein a message comprises the information for use in identifying whether power delivery was previously performed.
43. 43. A method according to claim 42, wherein the message is an identification message defined in the Qi standard.
44. 44. A method according to claim 42 or claim 43, wherein the message is at least one of A basic Identification message, a GET request identification message, A Report message and an Extended Power identification message.
45. 45. A method according to any one of claims 42 to 44, wherein the message comprises a field configured to comprise identification information for identifying at least one of the first and second wireless power apparatuses.A method according to any one of claims 42 to 45, wherein the message comprises at least one field configured to comprise information for indicating information is from a previously performed power delivery, a request for information or an intention to establish a further power delivery based on a previously performed power delivery.
46. 46. A method according to any preceding claim, wherein the further power delivery is established prior to performing an authentication process between the first and second wireless power apparatuses.
47. 47. A method according to claim 46, wherein the established further power delivery is halted upon a failed authentication.
48. 48. A method according to claims 46, wherein the authentication process is not performed for the further power delivery.
49. 49. A method according to any preceding claim, further comprising generating a notification to a user for identifying that one of the first wireless power apparatus and second wireless power apparatus is a trusted device in the case where the received information identifies that a power delivery was previously performed between the first and second wireless power apparatuses.
50. 50. A method according to any preceding claim, wherein the first wireless power apparatus is a wireless power transmitter apparatus, and wherein the second wireless power apparatus is a wireless power receiver apparatus.
51. 51. A method according to any preceding claims, wherein the previously performed power delivery and the further power delivery are performed in accordance with one or more steps of a Qi specification.
52. 52. A wireless power transmitter apparatus comprising: Means for transmitting power; and Control means configured to control the apparatus to perform a method according to any one of the preceding claims.
53. 53. A wireless power receiver apparatus comprising: Means for receiving power; and Control means configured to control the apparatus to perform a method according to any one of claims 1 to 52.
54. 54. A wireless power delivery system comprising: A means for transmitting power and a method for receiving power; One or more control means configured to control the system to perform a method according to any one of claims 1 to 52.
55. 55. A Computer program comprising instructions to cause a wireless power apparatus to perform a method according to any one of claims 1 to 51.
56. 56. A computer-readable storage medium storing instructions of a computer program for implementing a method according to one of claims 1 to 51.