Enhanced Wireless Power Transfer

Abstract

To provide a wireless power receiver and a method which negotiate with a power transmitter in a standards-compliant way to operate in a manner that is beyond the scope of the standard.SOLUTION: A wireless power transfer system 100 includes a power transmitter (PTx) 110 that wirelessly transfers power to a power receiver (PRx) 120 via inductive coupling 130. The power transmitter 110 receives input power that is converted to AC voltage having particular voltage and frequency characteristics by an inverter 114. The inverter 114 is controlled by a controller / communications module 116. The inverter controller and communications module may be implemented in a common system, such as a system based on a microprocessor, microcontroller, or the like. The controller / communications module monitors a transmitter coil and uses information derived therefrom to control the inverter as appropriate for a given situation.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] Wireless power transfer ("WPT"), sometimes known as inductive power transfer ("IPT"), has become more popular in several applications in recent years. One application where WPT / IPT is seeing increased use is in the consumer electronics space around devices such as mobile phones (i.e., smartphones) and their accessories (e.g., wireless earbuds, smart watches, etc.), as well as tablets and other types of portable computers and their accessories (e.g., styluses, etc.). Summary of the Invention

[0002] In some embodiments, the wireless power receiver can negotiate with the power transmitter in a standard-compliant manner to operate in a manner that exceeds the standard.

[0003] The wireless power receiver may include a receiver coil configured to receive power from a wireless power transmitter, a rectifier coupled to the receiver coil and configured to convert an AC voltage appearing across the receiver coil to a DC voltage delivered to a load, and a control and communication module coupled to the receiver coil and the rectifier. The controller and communication module may be further configured to receive in-band communication signals from the wireless power transmitter via the receiver coil and operate the rectifier to generate in-band communication signals that are transmitted to the transmitter via the receiver coil. The in-band communication signals may include communications conforming to a standard communication protocol negotiating a transition to an enhanced or extended mode of operation. The enhanced or extended mode of operation may include operating at one or more frequencies and power levels different from those specified by the standard communication protocol.

[0004] The wireless power receiver may further include an NFC communication module coupled to the control and communication module. In this case, the enhanced or extended operating mode may include delaying wireless power transmission to enable NFC communication with a corresponding NFC communication module in the wireless power transmitter. Communications conforming to a standard communication protocol for negotiating a transition to the enhanced or extended operating mode may include communications indicating one or more enhanced capabilities of the power receiver. Communications conforming to a standard communication protocol for negotiating a transition to the enhanced or extended operating mode may further include communications requesting one or more enhanced capabilities of the power transmitter. Communications conforming to a standard communication protocol for negotiating a transition to the enhanced or extended operating mode may further include communications acknowledging one or more enhanced capabilities of the power transmitter. Communications conforming to a standard communication protocol for negotiating a transition to the enhanced or extended operating mode may also include communications related to user interface features of at least one of the power transmitter and the power receiver.

[0005] The wireless power transmitter may include a transmitter coil configured to transmit power to the wireless power receiver, an inverter coupled to the transmitter coil and configured to convert an input voltage to an AC voltage transmitted to the transmitter coil, and a control and communication module coupled to the transmitter coil and the inverter. The controller and communication module may be further configured to receive in-band communication signals from the wireless power receiver via the transmitter coil and operate the inverter to generate in-band communication signals transmitted to the power received via the transmitter coil. The in-band communication signals may include communications conforming to a standard communication protocol negotiating a transition to an enhanced or extended mode of operation. The enhanced or extended mode of operation may include operating at a frequency or power level different from the frequency or power level specified by the standard communication protocol.

[0006] The wireless power transmitter may further include an NFC communication module coupled to the control and communication module. In this case, the enhanced or extended operating mode may include delaying wireless power transmission to enable NFC communication with a corresponding NFC communication module in the wireless power receiver. The communication conforming to the standard communication protocol may include negotiating a transition to the enhanced or extended operating mode, including communication indicating one or more enhanced capabilities of the power transmitter. The communication conforming to the standard communication protocol negotiating a transition to the enhanced or extended operating mode may further include communication requesting one or more enhanced capabilities of the power receiver. The communication conforming to the standard communication protocol negotiating a transition to the enhanced or extended operating mode may further include communication acknowledging one or more enhanced capabilities of the power receiver. The communication conforming to the standard communication protocol negotiating a transition to the enhanced or extended operating mode may also include communication related to user interface features of at least one of the power transmitter and the power receiver.

[0007] A method for negotiating wireless power transmission between a wireless power transmitter or wireless power receiver and a counterpart device may include initiating communication with the counterpart device using a standard communication protocol, communicating one or more enhanced features of the device to the counterpart device using the standard communication protocol, and determining whether the counterpart device is also capable of operating in accordance with each of the one or more enhanced features. If the counterpart device is not capable of operating in accordance with one or more of the enhanced features, the method may further include operating in a standard mode. Alternatively, if the counterpart device is capable of operating in accordance with one or more of the enhanced features, the method may further include negotiating a transition to an agreed-upon enhanced mode including one or more of the enhanced features. Communication between the device and its counterpart may be in-band or out-of-band communication. The enhanced features may include the ability to operate at frequencies or power levels different from those specified by the standard communication protocol. The enhanced features may include NFC communication capabilities, and the enhanced mode may include delaying wireless power transmission to enable NFC communication. The enhanced functionality may also include user interface functionality of the transmitter or receiver device, in which case the agreed upon enhanced mode may include an agreement between the device and its partner as to which device will provide information to the user regarding the status of wireless power transmission. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 illustrates a wireless power transmission system.

[0009] [Figure 2A] 1 illustrates wireless power transfer negotiation for operation in enhanced / extended wireless power transfer mode. [Figure 2B] 1 illustrates wireless power transfer negotiation for operation in enhanced / extended wireless power transfer mode. [Figure 2C] 1 illustrates wireless power transfer negotiation for operation in enhanced / extended wireless power transfer mode. [Figure 2D]1 illustrates wireless power transfer negotiation for operation in enhanced / extended wireless power transfer mode. [Figure 2E] 1 illustrates wireless power transfer negotiation for operation in enhanced / extended wireless power transfer mode.

[0010] [Figure 3] 10 shows a flowchart of receiver-side negotiation for enhanced / extended wireless power transfer mode.

[0011] [Figure 4] 10 shows a flowchart of transmitter-side negotiation for enhanced / extended wireless power transfer modes.

[0012] [Figure 5] 1 illustrates a flowchart of an NFC scanning process associated with an enhanced / extended wireless power transfer mode.

[0013] [Figure 6] 1 illustrates a high-level flowchart of power transfer negotiation for operating in an enhanced / extended wireless power transfer mode. DETAILED DESCRIPTION OF THE INVENTION

[0014] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed concepts. As part of this description, some of the drawings in the disclosure represent structures and devices in block diagram form for clarity. Also, in the interest of clarity, not all features of an actual implementation are described in the disclosure. Moreover, the language used herein has been chosen for purposes of readability and explanation, and not to limit or restrict the disclosed subject matter. Rather, the appended claims are intended for such purposes.

[0015] Various embodiments of the concepts of the present disclosure are illustrated by way of example, and not limitation, in the accompanying drawings, in which like reference numerals indicate similar elements. For simplicity and clarity of illustration, reference numerals have been repeated among the figures where appropriate to indicate corresponding or similar elements. Also, as described herein, numerous specific details have been described to provide a thorough understanding of implementations. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the relevant associated functionality being described. References to "an," "one," or "another" embodiment in this disclosure are not necessarily to the same or different embodiments, but rather mean at least one. Certain drawings are used to illustrate one or more embodiments or features of one or more species of the present disclosure, and not all elements in the drawings may be required for a given embodiment or species. Reference numerals, if provided in a given drawing, refer to the same element throughout the several drawings, but may not be repeated in all drawings. The drawings are not to scale unless otherwise indicated, and the proportions of certain parts may be exaggerated to better illustrate the details and features of the present disclosure.

[0016] FIG. 1 is a simplified block diagram of a wireless power transfer system 100. The wireless power transfer system includes a power transmitter (PTx) 110 that wirelessly transfers power to a power receiver (PRx) 120 via inductive coupling 130. The power transmitter 110 may receive input power that is converted by an inverter 114 to an AC voltage having specific voltage and frequency characteristics. The inverter 114 may be controlled by a controller / communications module 116 that operates as described further below. In various embodiments, the inverter controller and communications module may be implemented within a common system, such as a system based on a microprocessor, microcontroller, or the like. In other embodiments, the inverter controller may be implemented by a separate controller module and communications module having means for communication therebetween. The inverter 114 may be constructed using any suitable circuit topology (e.g., full bridge, half bridge, etc.) and may be implemented using any suitable semiconductor switching device technology (e.g., MOSFETs, IGBTs, etc., fabricated using silicon, silicon carbide, or gallium nitride devices).

[0017] The inverter 114 may send the generated AC voltage to the transmitter coil 112. In addition to the wireless coil that enables magnetic coupling to the receiver, the transmitter coil block 112 shown in FIG. 1 may include tuning circuitry, such as additional inductors and capacitors, that facilitate operation of the transmitter under various conditions, such as different degrees of magnetic coupling to the receiver or different operating frequencies. The wireless coil itself may be constructed in a variety of different ways. In some embodiments, the wireless coil may be formed as a winding of wire around a suitable bobbin. In other embodiments, the coil may be formed as a trace on a printed circuit board. Other configurations are possible and can be used in conjunction with the various embodiments described herein. The wireless transmitter coil may also include a core of magnetically permeable material (e.g., ferrite) configured to influence the magnetic flux pattern of the coil in a manner suitable for a particular application. The teachings herein may be applied in conjunction with any of a wide variety of transmitter coil configurations suitable for a given application.

[0018] The PTx controller / communications module 116 may monitor the transmitter coil and use information derived therefrom to control the inverter 114 as appropriate for a given situation. For example, the controller / communications module may be configured to operate the inverter 114 at a given frequency or output voltage depending on a particular application. In some embodiments, the controller / communications module may be configured to receive information from the PRx device and control the inverter 114 accordingly. This information may be received via the transmitter coil (i.e., in-band communication) or via a separate communication channel (not shown, i.e., out-of-band communication). In the case of in-band communication, the controller / communications module 116 may detect and decode signals (such as voltage, frequency, or load fluctuations) imposed by the PRx on the magnetic link to receive the information and may command the inverter to modulate the delivered power by manipulating various parameters (such as voltage, frequency, phase, etc.) to transmit the information to the PRx. In some embodiments, the controller / communications module may be configured to communicate data to the PRx employing frequency-shift keying (FSK) communication, in which the frequency of the inverter signal is modulated. The controller / communications module 116 may be configured to detect amplitude shift keying (ASK) or load modulation based communications from the PRx. In either case, the controller / communications module 126 may be configured to vary the current drawn at the receiver side from the PRx to the PTx, manipulate the waveform seen on the Tx coil, and send information from the PRx to the PTx. For out-of-band communications, an additional module may be provided to enable communication between the PTx and PRx, such as a Wifi, Bluetooth, or other wireless link, or any other suitable communications channel.

[0019] As noted above, controller / communications module 116 may be, for example, a single module provided on a single integrated circuit, or may be comprised of multiple modules / devices provided on different integrated circuits, or a combination of integrated circuits and discrete circuits having both analog and digital components. The teachings herein are not limited to any particular configuration of controller / communications circuitry.

[0020] The PTx device 110 may optionally include other systems and components, such as a near field communication ("NFC") module 118. In some embodiments, the NFC module 118 may communicate with a corresponding module or radio frequency identification (RFID) tag in the PTx via a power transmission coil. In other embodiments, the NFC module 118 may communicate with a corresponding module or tag using a separate physical channel 138. In some embodiments, it may be necessary to interrupt inductive power transmission to prevent interference with NFC communications, as described in more detail below.

[0021] As described above, the wireless power transfer system also includes a wireless receiver (PRx) 120. The wireless receiver may include a receiver coil 122 that may be magnetically coupled 130 to the transmitter coil 112. Similar to the transmitter coil 112 described above, the receiver coil block 122 shown in FIG. 1 may include tuning circuitry, such as additional inductors and capacitors, to facilitate operation of the transmitter under different conditions, such as different degrees of magnetic coupling to the receiver or different operating frequencies. The wireless coil itself may be constructed in a variety of different ways. In some embodiments, the wireless coil may be formed as a winding of wire around a suitable bobbin. In other embodiments, the coil may be formed as a trace on a printed circuit board. Other configurations are possible and can be used in conjunction with the various embodiments described herein. The wireless receiver coil may also include a core of magnetically permeable material (e.g., ferrite) configured to affect the magnetic flux pattern of the coil in a manner suitable for a particular application. The teachings herein may be applied in conjunction with any of a wide variety of receiver coil configurations suitable for a given application.

[0022] The receiver coil 122 outputs an induced AC voltage via the transmitter coil 112. This output AC voltage may be provided to a rectifier 124, which provides DC output power to one or more loads associated with the PRx device. The rectifier 124 may be controlled by a controller / communications module 126, which operates as described further below. In various embodiments, the rectifier controller and communications module may be implemented within a common system, such as a microprocessor-, microcontroller-, or other based system. In other embodiments, the rectifier controller may be implemented by a separate controller module and communications module having means for communication therebetween. The rectifier 124 may be constructed using any suitable circuit topology (e.g., full bridge, half bridge, etc.) and may be implemented using any suitable semiconductor switching device technology (e.g., MOSFETs, IGBTs, etc., fabricated using silicon, silicon carbide, or gallium nitride devices).

[0023] The PTx controller / communications module 126 may monitor the receiver coil and use information derived therefrom to control the rectifier 124 as appropriate for a given situation. For example, the controller / communications module may be configured to operate the rectifier 124 to provide a given output voltage depending on a particular application. In some embodiments, the controller / communications module may be configured to transmit information to the PTx device to effectively control the power sent to the receiver. This information may be transmitted via the transmitter coil (i.e., in-band communication) or via a separate communication channel (not shown, i.e., out-of-band communication). In the case of in-band communication, the controller / communications module 126 may transmit information to the PTx, for example, by modulating the load current or other electrical parameters of the received power. In some embodiments, the controller / communications module 126 may be configured to detect and decode signals (such as voltage, frequency, or load variations) imposed on the magnetic link by the PTx in order to receive information from the PTx. In some embodiments, the controller / communications module 126 may be configured to receive frequency shift keying (FSK) communications, where the frequency of the inverter signal is modulated to communicate data to the PRx. The controller / communications module 126 may also be configured to generate amplitude shift keying (ASK) communications or load modulation-based communications from the PRx. In either case, the controller / communications module 126 may be configured to vary the current drawn at the receiver side from the PRx to the PTx, manipulate the waveform seen on the Tx coil, and send information from the PRx to the PTx. For out-of-band communications, additional modules may be provided to enable communication between the PTx and PRx, such as Wi-Fi, Bluetooth, or other wireless links, or any other suitable communications channel.

[0024] As noted above, controller / communications module 126 may be, for example, a single module provided on a single integrated circuit, or may be comprised of multiple modules / devices provided on different integrated circuits, or a combination of integrated circuits and discrete circuits having both analog and digital components. The teachings herein are not limited to any particular configuration of controller / communications circuitry.

[0025] The PRx device 120 may optionally include other systems and components, such as a near field communication ("NFC") module 128. In some embodiments, the NFC module 128 may communicate with a corresponding module or radio frequency identification (RFID) tag within the PTx via a power transmission coil. In other embodiments, the NFC module 128 may communicate with a corresponding module or tag using a separate physical channel 138. In some embodiments, it may be necessary to interrupt inductive power transmission to prevent interference with NFC communications, as described in more detail below.

[0026] Many variations and extensions of the above-described wireless power transfer system 100 are possible, and the teachings below are applicable to any such variations and improvements.

[0027] As described above, the PRx controller / communications module 126 and the PTx controller / communications module 126 may communicate with each other to identify themselves to each other and negotiate power transfer between them. This identification and negotiation process may occur in conjunction with a standard-defined protocol, such as the protocol defined by the Wireless Power Consortium Qi standard, so that devices from different manufacturers can interoperate. Conformity to such a standard provides the benefits of interoperability at the potential expense of specialization. In other embodiments, the identification and negotiation process may occur in conjunction with a proprietary protocol determined by the device's manufacturer, which provides the benefits of improved flexibility and potentially scalable performance, with the drawback of a loss of interoperability with devices that do not implement the proprietary protocol.

[0028] To address this dilemma, the controller / communications module may be configured to initiate a negotiation process according to a standard-defined protocol, in which one, the other, or both devices may identify themselves, in a standard-compliant manner, as supporting an enhanced feature set that goes beyond the scope of the standard. If both devices are capable of operating according to this enhanced feature set, the devices may choose to operate according to the enhanced feature set. Otherwise, the devices may choose to operate in conjunction with the standards-based feature set. In one embodiment, the enhanced feature set may include the ability to operate at different frequencies, at different power levels, or in other ways beyond those defined in the existing standard.

[0029] 2A-2H illustrate exemplary communication exchanges between a wireless power receiver (PRx) 120 and a wireless power transmitter (PTx) 110 for transitioning from a first communications protocol regime to a second regime that includes one or more specific enhancements. In some embodiments, the first protocol regime is a standards-based regime, such as Qi. The enhancements in the second regime may be either an extended or enhanced version of the standard (e.g., a latter or alternative version), or may be an entirely separate, proprietary system. The various communication packets described may take any of a variety of forms, employing different packet structures, different modulation schemes for communicating the packets, etc. While the following description addresses the components of communication packets at a high level, it should be understood that any particular protocol implementation may specify different or additional data that may be included in these packets, as appropriate.

[0030] Referring to FIG. 2A , an exemplary negotiation process begins with the PRx 120 transmitting a series of messages 202-208 to the power transmitter 110. This exchange may be triggered by the PRx detecting its proximity to the PTx, as is commonly done in wireless power transfer systems. The exchange may occur using in-band communication at a frequency specified by the standard. In some embodiments, this frequency may be between about 100 kHz and about 250 kHz. In some embodiments, this frequency may be 128 kHz. In the illustrated example, four messages 202-208 correspond to messages transmitted according to the Qi standard. However, in some embodiments, there may be more or fewer messages, and they may conform to alternative standards or protocols.

[0031] The first message 202 may be a SIG packet, i.e., a signal strength packet according to the Qi standard. The second message 204 may be an ID packet, i.e., an identification packet according to the Qi standard. The third message 206 may be an XID, i.e., an extended identification packet according to the Qi standard. The fourth message 208 may be a CFG packet, i.e., a configuration packet according to the Qi standard. In some embodiments, these four packets may correspond to the "Ping" and "Configuration Phase" according to the Qi standard. Details of these packets, including the information contained therein and the effect of such packets on the system, are described in detail in the Qi standard version to which they pertain and will not be repeated here. It will be understood that various versions of the Qi standard may incorporate different versions of such packets, and that subsequent versions may combine, eliminate, or otherwise modify such packets. Therefore, the illustrated packets are provided herein merely as an example of a standard-compliant initialization, and other similar configurations may also be used.

[0032] Related to the above-mentioned communication is the XID packet. In the Qi standard, this optional packet may be used to provide additional information exchange between the PRx and the PTx. This additional information exchange may include identification of enhanced capabilities, such as an extension or enhancement of the standard or the ability to perform according to other non-standard (i.e., outside the scope of the standard) modes of operation. These performance modes not specified in the standards described herein are referred to as non-standard ("XS"). Thus, upon receiving communication from the PRx that it is capable of performing according to an extension or enhancement of the standard, the PTx may send a response packet 210, which is an XS ACK, i.e., an acknowledgment of the PRx's non-standard capabilities.

[0033] 2B, further communication between the PRx and the PTx is shown. Upon receiving an acknowledgement of the PRx's enhanced (XS) capabilities from the PTx, the PRx may transmit a further packet 212 requesting that the PTx provide the enhanced capabilities, if any. This may take the form of a "GET" request, in which the PRx requests that the PTx transmit its enhanced capabilities in the form of an XS XID packet, i.e., a packet that goes beyond the normative standard and provides additional capabilities beyond what the PTx can provide. This packet may provide an indication of various features beyond the normative standard that the PTx can provide, such as different power transfer parameters (voltage, power level, operating frequency, etc.), as well as one or more parameters related to the PTx required to operate in enhanced (XS) mode.

[0034] As an example, the PTx may indicate that it is capable of operating at a different frequency beyond that defined by the normative standard. In some cases, the PRx may be configured to prefer operating at this different frequency, if available, e.g., to avoid potential interference with other devices or systems. As a result, the PRx may initiate a series of communications to transition from its current standard-compliant operating frequency to the different non-standard frequency. As part of this communication process, the PRx may also attempt to exchange other information related to power transmission, including information related to the user interface (UI-related information) and other device systems, such as the NFC system described above. To that end, the communication shown in FIG. 2B may continue with the PRx requesting UI-related parameters (message 216) and the PTx reporting the requested UI-related parameters (message 218).

[0035] As an example, it may be desirable to provide feedback to a user indicating the state or status of a wireless power transfer system. For example, it may be useful to provide a visual indication (such as an LED or colored LED) or an audio notification (such as a beep or chime) of successful or failed power transfer configuration. Depending on the particular device used, either the PTx or PRx may or may not have a particular UI type available. For example, a charging pad may have a status LED but may not have a speaker that allows it to play a chime. Other devices, such as smartphones, may be capable of providing audio and visual indicators. Similarly, other devices, such as charging cases, may have limited UI capabilities. Thus, in order to provide a desired level of feedback to a user, devices may need to negotiate among themselves to determine which device has the capability to provide the desired feedback to the user.

[0036] In the illustrated embodiment, it is the PRx that decides which device will provide the necessary user feedback. Referring now to FIG. 2C , the PRx can communicate its decision, informed by its own capabilities and those received from the PTx in its XID packet, regarding how various user interface issues will be handled. This may be communicated to the PRx via a special request-user interface (SRQ UI) packet 220. The PTx may acknowledge this request / command (ACK packet 222), and both devices may proceed accordingly. Similarly, the PRx may indicate the desired operating frequency via a special request frequency (SRQ Freq) packet 224. The PTx may acknowledge this request / command (ACK packet 224), and both devices may proceed accordingly to operate at different frequencies, as described in more detail below. Additionally, the PRx may use a special request-NFC (SRQ NFC) packet 228 to request specific NFC parameters. These may include, for example, a delay between deactivating the current power and communication exchange at the default / standard frequency to allow an NFC scan to occur, as described in more detail below, and reactivating the power and communication exchange at the optional frequency requested in packet 224. PTx may acknowledge this request / command (ACK packet 230), and both devices may proceed accordingly. Finally, PRX may provide additional special requests pertaining to an enhanced / extended protocol, or may indicate the end of a special request with an SRQ End (Special Request End) packet 232. PTx may acknowledge this request / command (ACK packet 234), and both devices may proceed accordingly, for example, to transition to the new frequency, provide the desired UI interaction, and enable the NFC operation agreed upon in the foregoing exchange.

[0037] Referring now to FIG. 2D , the PRx may transmit an EPT (End Power Transfer) packet 236 according to the original standard, e.g., the Qi standard. It will be understood that this packet may vary depending on the particular standard and version being used. However, the point of this instruction (and the end of the current power / data exchange regime) is to transition from operation according to the original power transfer standard (e.g., at the standard-defined frequencies) to power transfer according to the enhanced / extended standard (e.g., at a different frequency according to the enhanced standard rather than according to the original standard) as negotiated in the preceding exchange. Thus, power transfer is disabled (238), which may allow time to perform an NFC scan, if negotiated (240). More generally, it should be noted that other types of out-of-band communication may be utilized, such as Bluetooth and RFID communication. Further details of such out-of-band communication, in this example, NFC scanning, are described below.

[0038] Following the disabling of power transfer 238 and optional NFC scanning 240 (or other activity occurring during the negotiated delay), power transfer may resume in enhanced mode, e.g., at a different frequency, beginning with message exchanges 242-248. In some embodiments, this resumption in enhanced mode is responsive to successful communication between the PTx and PRx during the optional out-of-band communication period (e.g., NFC scanning 240). In the illustrated embodiment, this begins with the PRX sending a series of messages that conform to the extended or enhanced standard ("XS"), otherwise matching the basic pattern corresponding to the initial standard-compliant initiation or "ping." As previously mentioned, the exchange may occur using in-band communication at a frequency specified by the extended or enhanced standard. In some embodiments, this frequency may be between approximately 360 kHz, although other frequencies may be used.

[0039] In the illustrated exemplary exchange, the first message 242 may be an XS:SIG packet, i.e., a signal strength packet according to the extended standard. The second message 244 may be an XS:ID packet, i.e., an identification packet according to the extended standard. The third message 246 may be an XS:XID packet, i.e., an extended identification packet according to the extended standard. The fourth message 248 may be an XS:CFG packet, i.e., a configuration packet according to the extended standard. In some embodiments, these four packets may correspond to the "Ping" and "Configuration Phases" generally consistent with the Qi standard. In other embodiments, the exchange may include more or fewer messages, may be entirely unique, or may generally correspond to other standards-based communication protocols. Thus, the illustrated packets are provided here merely as an example of a ping or initialization procedure, and other similar configurations may also be used. In some embodiments, this ping or initialization procedure may be used to confirm parameters negotiated in the preceding special request exchange described above.

[0040] 2E, establishing power transmission according to the enhanced standard (e.g., at a different frequency) may require the exchange of further information between the receiver and transmitter. Accordingly, the PRx may request the PTx's extended identification information using message / packet 252, XS:GET PTx XID (i.e., enhanced standard, get transmitter extended identification information). In response, the PTx may provide the requested information via message / packet 254, PTx XID. The PRx may also provide an indication of its capabilities to the PTX using message 256, XS:SEND PRx Cap (enhanced standard, send receiver capabilities). This transmission may be acknowledged by the PTx with acknowledgement 258. Finally, there may be a further exchange in which the PRx sends one or more configuration packets, here indicated by packet 260, XS:SEND CFGn (enhanced standard, send configuration n), where n is any of essentially any number of packets necessary to exchange the necessary information. Each of these messages may be acknowledged by acknowledgement message / packet 262. As a result of the configuration exchange, power transfer according to the reinforced standard may commence (264).

[0041] The foregoing message / packet exchanges are exemplary. Extended standard (XS) communications may include more, fewer, or different message exchanges required to establish power transmission according to various extensions to the underlying standard. Furthermore, each message or packet may include various combinations of information necessary for power contract negotiation between the power receiver and the power transmitter. Furthermore, while the illustrated process is shown as being driven by the power receiver, in some embodiments, the power transmitter (PTx) may determine various configuration parameters rather than relying on the power receiver (PRx) to do so. Therefore, the foregoing description should be considered merely one example of a method for facilitating a transition from a standard-compliant wireless transmission mode to a wireless transmission mode based on an extension or enhancement of that standard.

[0042] FIG. 3 shows a simplified decision tree / flowchart 300 illustrating the transition of a receiver (PRx) from a standard-compliant wireless power transmission mode to a wireless power transmission mode according to an extension or enhancement of such standard (e.g., the frequency is not specified in the standard). The process begins with a “Ping Phase 302” in which the PRx and PRx begin communication. This ping phase may correspond, for example, to the message exchange described above in FIG. 2A , which generally corresponds to the ping phase defined by the Qi standard, or any other suitable standards-based exchange. From this point, the process proceeds to block 304, where the receiver reports its identification information and extended identification information, again in a manner that conforms to the standard. As outlined above, the extended identification information packet defined by the standard may enable communication of features outside the scope of the standard. In block 308, the PRx may report / acknowledge receipt of the configuration packet received from the PTx. In block 310, the PRx may determine whether the PTx can operate in conjunction with one or more enhancements or extensions desired by the PRx. If not, the process may proceed to block 312, where reference mode power transfer is provided in conjunction with standard. Otherwise, if the PTx provides acknowledgment of the extended / enhanced capabilities requested by the PRx, the system may proceed to negotiating extended mode power transfer 314 as described above, and then transition to enhanced / extended mode in block 316.

[0043] FIG. 4 shows a simplified decision tree / flowchart 400 illustrating the transition of a transmitter side (PTx) from a standard-compliant wireless power transmission mode to a wireless power transmission mode according to an extension or enhancement of such standard (e.g., the frequency is not specified in the normative standard). The process begins with device detection 402, which may be provided by any number of sensors designed to detect when a PTx device is brought within range of the PTx. This leads to a digital ping phase 404 (corresponding to the Rx-side digital ping phase 302), described in more detail above. Next, in block 406, the PTx receives an ID packet (406) and an XID packet (408), if expected based on the contents of the ID packet. All of these communications may conform to industry standards, as discussed above. In block 410, the PTx may determine whether an XID packet has been received. If not, it may enter standard mode power transmission (or shutdown, if desired) (block 412). Alternatively, if an XID packet is received, the PTx may analyze the packet's contents to determine whether the PRx can operate in enhanced / extended mode. If not, the PTx may transition to standard mode or disable power transfer (block 412). If so, the PTx may determine whether the PRx requested standard (standard-compliant mode) (block 416). If so, the above mode may be entered. Alternatively, the PTx may receive configuration phase packets sent by the PRx in block 306 above (blocks 418 / 420). These packets may be acknowledged by the PTx (block 422), and the PTx may then determine whether to resume and proceed to the ping phase or the extended / extended negotiation phase (block 426), which corresponds to the receiver-side negotiation phase in block 314 (block 422).

[0044] Returning briefly to FIG. 2D , as described above, after a negotiation phase in which the PRx and PTx agree to transition to a power transfer mode compliant with an extended / enhanced version of the standard that differs from the baseline standard (e.g., operating at a different frequency than that defined by the standard), the initially established standard power transfer may be disabled before being reactivated in the extended / enhanced mode (block 238). In some embodiments, the exchange between the PRx and PTx may include a delay before reactivation (e.g., as specified in the SRQ NFC block 228 described above) to allow time for NFC communication between the PRx and PTx. This delay may be provided because power transfer may interfere with NFC processes, which may use similar frequencies. Additionally, the high power levels associated with wireless power transfer may, in some cases, cause damage to NFC devices. Therefore, in the negotiation process described above, the PRx and PTx may negotiate a time to allow for NFC scanning.

[0045] NFC communications may be used for any of a variety of purposes. For example, in some embodiments, NFC communications may be used to provide PRx capabilities, characteristics, or parameters to the PTx, or vice versa. These may be used to confirm information provided in the various communications and negotiations described above. In other cases, NFC communications may be used to provide information exchanges that would not otherwise be possible or feasible using the techniques described above. In some embodiments, NFC communications may be used to read one or more NFC devices located on either the PRx or the PTx. These NFC tags may be used to perform additional functions, including, but not limited to, authentication, providing software / firmware updates to be delivered from the PRx to the PTx or vice versa, confirming power parameters negotiated in a previous phase, etc.

[0046] FIG. 5 shows a high-level flowchart 500 of an NFC scanning process. Starting at block 502, devices may perform their initial negotiation as described above, followed by a power transfer delay (block 504) and NFC scan (506) as described above. The duration of the delay may be negotiated to take into account the NFC function to be performed. For example, a relatively short task, such as authentication or verification of negotiated power transfer parameters, may require a relatively short duration. Alternatively, a process, such as a firmware update, may require a longer duration. The negotiated power transfer delay time may take these differences into account. Furthermore, if a device initially specifies a particular power transfer delay period for an NFC scan but discovers more devices that need to be read during a subsequent NFC scan, the device may negotiate a subsequent longer power transfer delay period to allow sufficient time to scan all of the tags. For example, in block 508, it may be determined whether all NFC devices have been read. If so, power transfer may be enabled or re-enabled (according to the enhanced / extended power transfer mode) in block 510. If not, the device may negotiate a longer power transfer delay to allow for further NFC scans (block 512).

[0047] In addition to the above, there may be some cases where it is desirable to simplify the negotiation process described above. As one example, a PRx device may have a dead battery, making it difficult or impossible to engage in a more protracted power contract negotiation process. In that case, the PRx device may indicate a preferred frequency in the XID packet described above with respect to element 206 of FIG. 2A. Recall that, as discussed above, the XID packet was used to inform the PTx that the device is capable of various enhanced non-standard power transfer modes. Instead, in this particular example, the PRx simply provides preferred / desired power parameters (such as operating frequency), and the PTx device complies, if possible.

[0048] FIG. 6 shows a high-level flowchart of a power negotiation process 600 for an extended or enhanced charging mode while remaining compliant. The process may be performed in either of both devices, as described more specifically above. The process may begin by initiating a standards-based negotiation at block 602. This negotiation may be performed using standards-compliant mechanisms to ensure interoperability with devices that do not support the desired enhanced or extended features. In some embodiments, these standards-compliant mechanisms may be provided by the Wireless Power Consortium Qi standard or any other suitable wireless power transmission standard. However, at block 604, standards-compliant mechanisms may be used to signal the enhanced features. In some embodiments, this may include an “XID” (Extended Identification) packet provided in the Qi standard, and may optionally include additional mechanisms for exchanging the required information. In other embodiments, other standards-compliant mechanisms may be used, as appropriate for different versions of the standard, or for completely different standards. At block 606, the devices may determine whether both devices are capable of operating in accordance with the desired enhanced or extended mode or functionality. If not, the device may proceed to operate in a standards-compliant mode, in which case wireless power transmission may occur in accordance with the relevant standard (block 608).

[0049] Otherwise, if it is determined in block 606 that the device is capable of operating in an extended / enhanced mode other than that specified in the standard, the device may negotiate a transition to the desired extended or enhanced mode (block 610). These extended or enhanced modes may provide power transfer in a manner that does not conform to the normative standard, including, for example, operation at a different frequency, a different voltage, a different power level, etc. Once an agreed-upon enhanced or enhanced mode is agreed upon, the device may transition to the agreed-upon enhanced or enhanced mode and operate accordingly (block 612).

[0050] The foregoing describes exemplary embodiments of a wireless power transmission system capable of negotiating enhanced / extended modes of operation while remaining compliant with wireless power transmission standards that do not support such modes. Such systems may be used in a variety of applications, but may be particularly advantageous when used in conjunction with personal electronic devices, such as mobile computing devices (e.g., laptop computers, tablet computers, smartphones, etc.), and their accessories (e.g., wireless earbuds, styluses, and other input devices, etc.), as well as wireless charging accessories (e.g., charging mats, pads, stands, etc.). While numerous specific features and various embodiments have been described, it should be understood that, unless otherwise specified as mutually exclusive, the various features and embodiments may be combined in various permutations in a particular implementation. Accordingly, the various embodiments described above are provided by way of example only and should not be construed as limiting the scope of the present disclosure. Various modifications and variations can be made to the principles and embodiments herein without departing from the scope of the present disclosure and without departing from the scope of the claims.

[0051] The above describes exemplary embodiments of a wireless power transmission system capable of transmitting specific information between the PTxs and PRxs in the system. The present disclosure contemplates that the passing of this information improves the ability of devices to provide wireless power signals to each other in an efficient and non-damaging manner to facilitate battery charging. It is contemplated that some practitioners of the present technology may consider passing identifiers such as serial numbers, UIDs, manufacturer IDs, MAC addresses, etc. to aid in identifying the PTxs and PRxs, and particularly their wireless capabilities, to each other.

[0052] Entities implementing the present technology should take care to ensure that, to the extent any sensitive information is used in a particular implementation, well-established privacy policies and / or practices are adhered to. Specifically, such entities would be expected to implement and consistently apply privacy practices that are generally recognized as meeting or exceeding industry or government requirements for maintaining user privacy. Implementers should inform users of where personally identifiable information is expected to be transmitted in the wireless power transmission system and allow users to "opt in" or "opt out" of participation. For example, such information may be presented to users when they place their device on a power transmitter.

[0053] It is the intent of this disclosure that personal information data, if any, should be managed and handled in a manner that minimizes the risk of unintentional or unauthorized access or use. Risk can be minimized by limiting data collection and deleting data when it is no longer needed. Furthermore, where applicable, data de-identification can be used to protect user privacy. For example, a device identifier may be partially masked to communicate a device's power characteristics without uniquely identifying the device. De-identification may be facilitated by removing identifiers, where appropriate, controlling the amount or specificity of stored data (e.g., collecting location data at a city level rather than an address level), controlling how data is stored (e.g., aggregating data across users), and / or other methods such as differential privacy. Robust encryption may also be utilized to reduce the likelihood that communications between inductively coupled devices can be spoofed.

Claims

1. A wireless power receiver, a receiver coil configured to receive power from a wireless power transmitter; a rectifier coupled to the receiver coil configured to convert an AC voltage appearing across the receiver coil to a DC voltage that is delivered to a load; a control and communication module coupled to the receiver coil and the rectifier, the control and communication module comprising: receiving an in-band communication signal from the wireless power transmitter via the power receiver coil; configured to operate the rectifier to generate an in-band communication signal that is transmitted to the wireless power transmitter via the receiver coil; a wireless power receiver, wherein the in-band communication signals transmitted via the receiver coil to the wireless power transmitter include communications negotiating operation using an enhanced feature set, the in-band communication signals conforming to a standard communication protocol, the enhanced feature set corresponding to an extended or enhanced version of the standard communication protocol, the enhanced feature set associated with operation at higher frequencies and higher power levels;

2. 2. The wireless power receiver of claim 1, wherein the higher frequency is 360 kHz.

3. The wireless power receiver of claim 1 , wherein the in-band communication signal includes an extended identification packet that conforms to a version of the Qi standard.

4. The wireless power receiver of claim 1 , wherein the in-band communication signal conforms to a standard communication protocol and the enhanced feature set corresponds to a proprietary system.

5. The wireless power receiver of claim 4 , wherein the enhanced feature set is associated with operation at higher frequencies and higher power levels.

6. 6. The wireless power receiver of claim 5, wherein the higher frequency is 360 kHz.

7. The wireless power receiver of claim 5 , wherein the in-band communication signal includes an extended identification packet that conforms to a version of the Qi standard.

8. The wireless power receiver of claim 1 , wherein the control and communication module is further configured to suspend or terminate power transfer after negotiating operation using the enhanced feature set.

9. 10. The wireless power receiver of claim 8, wherein the wireless power receiver suspends or terminates power transfer by sending an End Power Transfer (EPT) packet according to the Qi standard.

10. The wireless power receiver of claim 8 , wherein the wireless power receiver pauses power transmission to allow time for NFC scanning.

11. The wireless power receiver of claim 1 , wherein the control and communication module is further configured to switch to a new power transmission frequency after negotiating operation using the enhanced feature set.

12. The wireless power receiver of claim 11 , wherein the new power transmission frequency is 360 kHz.

13. 12. The wireless power receiver of claim 11, wherein after negotiating operation using the enhanced capability set, the control and communication module is further configured to transmit an additional message including at least one extended identification packet at the new power transfer frequency.

14. 12. The wireless power receiver of claim 11, wherein after negotiating operation using the enhanced capability set, the control and communication module is further configured to transmit an additional message at the new power transmission frequency that includes a request for at least one transmitter extended identification packet.

15. 12. The wireless receiver of claim 11, wherein after negotiating operation using the enhanced capability set, the control and communication module is further configured to transmit additional messages at the new power transfer frequency, the additional messages including at least one message identifying capabilities of the wireless receiver at the new power transfer frequency.

16. A wireless power transmitter, a transmitter coil configured to transmit power to a wireless receiver; an inverter coupled to the transmitter coil and configured to convert an input voltage to an AC voltage that is delivered to the transmitter coil; a control and communication module coupled to the transmitter coil and the inverter, the control and communication module comprising: receiving an in-band communication signal from the wireless power receiver via the power transmitter coil; further configured to operate the inverter to generate an in-band communication signal that is transmitted to the wireless power receiver via the transmitter coil; a wireless power transmitter, wherein the in-band communication signals received from the wireless power receiver include communications negotiating operation using an enhanced feature set, the in-band communication signals conforming to a standard communication protocol, the enhanced feature set corresponding to an extended or enhanced version of the standard communication protocol, the enhanced feature set associated with operation at higher frequencies and higher power levels;

17. 17. The wireless power transmitter of claim 16, wherein the higher frequency is 360 kHz.

18. 17. The wireless power transmitter of claim 16, wherein the in-band communication signal conforms to a standard communication protocol and the enhanced feature set corresponds to a proprietary system.

19. 20. The wireless power transmitter of claim 18, wherein the enhanced feature set is associated with operation at higher frequencies and higher power levels.

20. 20. The wireless power transmitter of claim 19, wherein the higher frequency is 360 kHz.

21. 20. The wireless power transmitter of claim 19, wherein the in-band communication signal includes an extended identification packet that conforms to a version of the Qi standard.

22. A method for negotiating wireless power transmission between a device that is a wireless power transmitter or a wireless power receiver and a counterpart device, comprising: Initiating communication with the other device; communicating one or more capabilities of the device to the other device, the one or more capabilities including a capability to operate using an enhanced feature set; determining whether the other device is capable of operating with the enhanced feature set; and if the other device is capable of operating with the enhanced feature set, selecting an operating frequency and power level corresponding to the enhanced feature set.

23. 23. The method of claim 22, wherein the communication between the device and its partner is an in-band communication conforming to a standard communication protocol, and the enhanced feature set corresponds to an extended or enhanced version of the standard communication protocol.

24. 23. The method of claim 22, wherein the communication between the device and its partner is in-band communication conforming to a standard communication protocol, and the enhanced feature set corresponds to a proprietary system.

25. 23. The method of claim 22, wherein the selected operating frequency corresponding to the enhanced feature set is 360 kHz.

26. 25. The method of claim 23 or 24, wherein the in-band communication includes an extended identification packet that complies with a version of the Qi standard.

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