Coupling estimation in wireless charging systems

Abstract

Regarding coupling estimation in wireless charging systems. [Solution] In order to handle k estimation errors in a wireless power transmission system, k estimation is performed during the digital ping phase of wireless power transmission negotiation, it is determined that an error has occurred while performing k estimation, it is determined whether a wireless power receiver is available to assist in correcting the error, and in response to the determination that an error has occurred while performing k estimation and a wireless power receiver is available to assist in correcting the error, the wireless power transmitter performs a full-mode error correction procedure in which it works with the wireless power receiver to correct the error that occurred during k estimation, and in response to the determination that a wireless power receiver is unavailable to assist in correcting the error, the wireless power transmitter performs a limited-mode error correction procedure in which it attempts to correct the error that occurred during k estimation without cooperation from the wireless power receiver.

Description

Background Art

[0004] ,

[0001] Wireless power transmission is used in various electronic devices. For example, smartphones, tablet computers, smartwatches, wireless earphones, styluses, etc. can adopt wireless power transmission to facilitate charging of the battery in the device and / or to supply power to the device during operation.

Summary of the Invention

[0002] A method for handling k-estimation errors in a wireless power transmission system including a wireless power transmitter and a wireless power receiver can be performed by the wireless power transmitter, and includes performing k-estimation during a digital ping phase of wireless power transmission negotiation, determining that an error has occurred while performing k-estimation, determining whether the wireless power receiver is available to assist in correcting the error, in response to determining that an error has occurred while performing k-estimation and that the wireless power receiver is available to assist in correcting the error, the wireless power transmitter performing a full-mode error correction procedure to correct the error that occurred during k-estimation in cooperation with the wireless power receiver, and in response to determining that an error has occurred while performing k-estimation and that the wireless power receiver is not available to assist in correcting the error, the wireless power transmitter attempting to correct the error that occurred during k-estimation without cooperation from the wireless power receiver by performing a restricted-mode error correction procedure.

[0003] Determining that an error has occurred while performing k-estimation can be based on the wireless power receiver transmitting an extended identification packet having a restriction field set to 1 in the case of restricted mode.

[0004] Performing a limited-mode error correction procedure may further include removing the power signal and resetting the wireless power link, performing one or more correction actions, and initiating a further digital ping phase. One or more correction actions may include initiating a further digital ping at a second voltage level different from the first voltage level of the digital ping. Performing a full-mode error correction procedure may further include entering a negotiation phase with an error, and communicating the error to the wireless power receiver. Communicating the error to the wireless power receiver may include sending a Negative Response (NAK) packet in response to a Configuration (CFG) packet from the PRx, and sending an Error (ERR) packet in response to a GET packet from the wireless power receiver.

[0005] Performing a full-mode error correction procedure may further include completing the wireless power transmission negotiation phase in response to receiving information from the wireless power receiver that enables error clearing; receiving a request from the wireless power receiver to terminate the negotiation phase in response to not receiving information from the wireless power receiver that enables error clearing; removing the power signal and resetting the wireless power link; performing one or more correction actions; and initiating a further digital ping phase. Additional information received from the wireless power receiver may include ecosystem scaling factors. Ecosystem scaling factors may be received in ecosystem scaling factor packets. Information that enables error clearing may be included in EPT / rst packets from the wireless power receiver.

[0006] The wireless power transmitter may include control and communication circuits that perform a k estimation during the digital ping phase of wireless power transmission negotiation, determine if an error has occurred while performing the k estimation, determine whether a wireless power receiver is available to assist in correcting the error, and, in response to the determination that an error has occurred while performing the k estimation and that a wireless power receiver is available to assist in correcting the error, the wireless power transmitter performs a full-mode error correction procedure in which it works with the wireless power receiver to correct the error that occurred during the k estimation. The full-mode error correction procedure may include entering a negotiation phase with the error and communicating the error to the wireless power receiver. Alternatively, in response to the determination that an error has occurred while performing the k estimation and that a wireless power receiver is unavailable to assist in correcting the error, the transmitter control circuit may perform a limited-mode error correction procedure in which the wireless power transmitter attempts to correct the error that occurred during the k estimation without assistance from the wireless power receiver. The limited-mode error correction procedure may include removing the power signal, resetting the wireless power link, performing one or more correction actions, and initiating a further digital ping phase.

[0007] Determining that an error occurred while performing k estimation may be based on receiving an extended identification packet from the wireless power receiver with a restriction field set to 1 in restriction mode. One or more corrective actions may include the control and communication circuit initiating a further digital ping at a second voltage level different from the first voltage level of the digital ping. Communicating the error to the wireless power receiver may include the control and communication circuit sending a negative response (NAK) packet in response to a configuration (CFG) packet from the PRx and sending an error (ERR) packet in response to a GET packet from the wireless power receiver. Performing a full-mode error correction procedure may further include completing the wireless power transmission negotiation phase in response to receiving information from the wireless power receiver that enables the error to be cleared, the information that enables the error to be cleared being contained in the EPT / rst packet from the wireless power receiver received by the control and communication circuits, receiving a request from the wireless power receiver to terminate the negotiation phase in response to not receiving information that enables the error to be cleared from the wireless power receiver, removing the power signal and resetting the wireless power link, performing one or more correction actions, and initiating a further digital ping phase. Additional information received from the wireless power receiver may include ecosystem scaling factors received in ecosystem scaling factor packets.

[0008] A method for handling a k-estimation error in a wireless power transmission system including a wireless power transmitter and a wireless power receiver may be performed by the wireless power receiver and may include: receiving an instruction from the wireless power transmitter that an error occurred during the digital ping phase; receiving an indicated cause of the error from the wireless power transmitter during the digital ping phase; sending additional information to the wireless power transmitter in response that the indicated cause is a k-estimation error and correctable by the wireless power receiver, thereby working with the wireless power transmitter to resolve the error; and sending a reset message to the wireless power transmitter in response that the indicated cause is not correctable by the wireless power receiver, thereby causing the wireless power transmitter to attempt to resolve the error itself.

[0009] Additional information may include an extended identification packet with a restriction field set to 1 in restriction mode. Sending additional information to the wireless power transmitter and thereby cooperating with the wireless power transmitter to resolve errors may include sending the ecosystem scaling factor in the ecosystem scaling factor packet. Reset messages may include EPT / rst packets.

[0010] The wireless power receiver may include control and communication circuits that receive an instruction from the wireless power transmitter that an error occurred during the digital ping phase, receive the indicated cause of the error from the wireless power transmitter during the digital ping phase, and in response that the indicated cause is a k-predicted error and correctable by the wireless power receiver, transmit additional information to the wireless power transmitter to resolve the error in cooperation with the wireless power transmitter, and in response that the indicated cause is not correctable by the wireless power receiver, transmit a reset message to the wireless power transmitter to cause the wireless power transmitter to attempt to resolve the error itself.

[0011] Additional information may include an extended identification packet with a restriction field set to 1 in restricted mode. Additional information may include sending the ecosystem scaling factor in the ecosystem scaling factor packet. A reset message may include an EPT / rst packet. [Brief explanation of the drawing]

[0012] [Figure 1] This is a simplified block diagram of a wireless power transmission system.

[0013] [Figure 2] This is a flowchart of techniques for handling errors in the k estimation process of wireless power transmission systems.

[0014] [Figure 3] This figure shows a table of potential k estimation error sources and solution methods.

[0015] [Figure 4] This is an exemplary communication flow between PTx and PRx using the k-estimated error handling process in restricted mode.

[0016] [Figure 5] This is an exemplary communication flow between PTx and PRx using the k-estimate error handling process in the first scenario of full mode.

[0017] [Figure 6] This is an exemplary communication flow between PTx and PRx using the k-estimate error handling process in the second scenario of full mode.

[0018] [Figure 7] This figure shows an exemplary data packet structure for exchanging ecosystem scaling factors between PTx and PRx.

[0019] [Figure 8] This figure shows an exemplary data packet structure for exchanging error information between PTx and PRx. [Modes for carrying out the invention]

[0020] The following description provides numerous specific details for the sake of clarity and to enhance understanding of the disclosed concepts. As part of this description, some of the drawings in this disclosure represent structures and devices in block diagram form to avoid obscuring the invention. For clarity, not all features of actual implementations are described herein. Furthermore, the language used herein has been selected solely for readability and explanatory purposes and not to limit or restrict the subject matter disclosed. Rather, the appended claims are intended for this purpose. Any trademarks referenced herein are intended solely for identifying examples and are the property of their respective owners.

[0021] Various embodiments of the disclosed concepts are shown in the accompanying drawings as examples, not as limitations, and similar reference numbers indicate similar elements. For the sake of illustration simplification and clarity, where appropriate, reference numbers are repeated in different drawings to indicate corresponding and / or similar elements. In addition, numerous specific details are provided to provide a complete understanding of the implementations described herein. In other examples, methods, procedures, and components are not described in detail so as not to obscure the relevant functions described. References to “an,” “one,” or “another” embodiments in this disclosure do not necessarily mean the same or different embodiments, but mean at least one. Given drawings are used to illustrate multiple embodiments or species of this disclosure, and not all elements in the drawings may be required in a given embodiment or species. Reference numbers, where provided in a given drawing, refer to the same element across several drawings, but are not repeated in all drawings. Unless otherwise indicated, the drawings are not to actual scale, and the proportions of certain parts may be exaggerated to better illustrate the details and features of this disclosure.

[0022] FIG. 1 shows a simplified block diagram of a wireless power transmission system 100. The wireless power transmission system includes a power transmitter (PTx) 110 that wirelessly transmits power to a power receiver (PRx) 120 via an inductive coupling 130 or the like. The power transmitter 110 can receive input power that is converted by an inverter 114 into an AC voltage having specific voltage and frequency characteristics. The inverter 114 can be controlled by a controller / communication module 116 that operates as further described below. In various embodiments, the inverter controller and communication module may be implemented in a common system such as a system based on a microprocessor, a microcontroller, or the like. In other embodiments, the inverter controller may be implemented by separate controller and communication modules that have communication means therebetween. The inverter 114 may be configured 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., MOSFET, IGBT, etc. fabricated using silicon, silicon carbide, or gallium nitride devices).

[0023] The inverter 114 can deliver 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 Figure 1 may include tuning circuit components such as additional inductors and capacitors to facilitate the operation of the transmitter under different conditions, such as different degrees of magnetic coupling to the receiver and different operating frequencies. The wireless coil itself can be configured in a variety of different ways. In some embodiments, the wireless coil may be formed as a winding of wire wound on a suitable bobbin. In other embodiments, the wireless coil may be formed as a trace on a printed circuit board. Other arrangements are also possible and can be used in conjunction with the various embodiments described herein. The wireless transmitter coil may also include a core of a 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 can be applied in conjunction with any of the wide variety of transmitter coil arrangements suitable for a given application.

[0024] The PTx controller / communication module 116 can monitor the power transmission coil and use the information derived therefrom to control the inverter 114 appropriately for a given situation. For example, the controller / communication module can be configured to operate the inverter 114 at a given frequency or output voltage according to a particular application. In some embodiments, the controller / communication module can be configured to receive information from the PRx device and control the inverter 114 accordingly. This information may be received via the power transmission 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 / communication module 116 can detect and decode signals (such as voltage, frequency, or load variations) imposed on the magnetic link by the PRx to receive information, and can command the inverter to modulate the delivered power by manipulating various parameters (such as voltage, frequency, etc.) of the generated voltage to transmit information to the PRx. In some embodiments, the controller / communication module can be configured to employ frequency shift keying (FSK) communication in which the frequency of the inverter signal is modulated to communicate data to the PRx. The controller / communication module 116 can be configured to detect amplitude shift keying (ASK) communication or load modulation-based communication from the PRx. In either case, the controller / communication module 126 can be configured to change the current drawn on the receiver side and manipulate the waveform seen on the Tx coil to deliver information from the PRx to the PTx. In the case of out-of-band communication, an additional module enabling communication between the PTx and the PRx, such as WiFi, Bluetooth®, or other wireless link, or any other suitable communication channel, may be provided.

[0025] As described above, the controller / communication module 116 may be, for example, a single module on a single integrated circuit, or it may consist of multiple modules / devices on different integrated circuits, or a combination of an integrated circuit having both analog and digital components and discrete circuits. The teachings herein are not limited to any particular arrangement of controller / communication circuit components.

[0026] The PTx device 110 may optionally include other systems and components, such as a separate communication module 118. In some embodiments, the communication module 118 can communicate with the corresponding module tag in the PRx via a power transmission coil. In other embodiments, the communication module 118 can communicate with the corresponding module using a separate physical channel 138.

[0027] As described above, the wireless power transmission system also includes a wireless power receiver (PRx) 120. The wireless power receiver may include a receiver coil 122 that can be magnetically coupled to the transmitter coil 112. Similar to the transmitter coil 112 described above, the receiver coil block 122 shown in Figure 1 may include tuning circuit components such as additional inductors and capacitors to facilitate the operation of the transmitter under different conditions, such as different degrees of magnetic coupling to the receiver and different operating frequencies. The wireless coil itself can be constructed in a variety of different ways. In some embodiments, the wireless coil may be formed as a winding of wire wound on a suitable bobbin. In other embodiments, the wireless coil may be formed as a trace on a printed circuit board. Other arrangements are also possible and can be used in conjunction with the various embodiments described herein. The wireless receiver coil may also include a core of a 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 can be applied in conjunction with any of the wide variety of receiver coil arrangements suitable for a given application.

[0028] The receiver coil 122 outputs an AC voltage induced internally by magnetic induction via the transmitter coil 112. This output AC voltage can be supplied to a rectifier 124 that provides DC output power to one or more loads associated with the PRx device. The rectifier 124 can be controlled by a controller / communication module 126 that operates as described further below. In various embodiments, the rectifier controller and communication module may be implemented in a common system, such as a system based on a microprocessor, microcontroller, etc. In other embodiments, the rectifier controller may be implemented by a separate controller module and communication module with means of communication between them. The rectifier 124 may be configured 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).

[0029] The PRx controller / communication module 126 can monitor the receiver coil and use the information derived therefrom to appropriately control the rectifier 124 according to a given situation. For example, the controller / communication module may be configured to operate the rectifier 124 to provide a given output voltage according to a specific application. In some embodiments, the controller / communication module may be configured to transmit information to the PTx device in order to effectively control the power delivered to the receiver. This information may be received and transmitted via the power transmission 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 / communication module 126 may transmit information to the PTx by modulating, for example, the load current or other electrical parameters of the received power. In some embodiments, the controller / communication module 126 may be configured to detect and decode signals (such as voltage, frequency, or load fluctuations) applied to the magnetic link by the PTx in order to receive information from the PTx. In some embodiments, the controller / communication module 126 may be configured to receive frequency-shift keying (FSK) communications in which the frequency of the inverter signal is modulated to communicate data to the PRx. The controller / communication module 126 may be configured to generate amplitude-shift keying (ASK) communications or load-modulation-based communications from the PRx. In either case, the controller / communication module 126 may be configured to change the current drawn out at the receiver side to manipulate the waveform observed on the Tx coil in order to deliver 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 the PRx, such as WiFi, Bluetooth®, or other wireless links, or any other suitable communication channel.

[0030] As described above, the controller / communication module 126 may be, for example, a single module on a single integrated circuit, or it may consist of multiple modules / devices on different integrated circuits, or a combination of an integrated circuit having both analog and digital components and discrete circuits. The teachings herein are not limited to any particular arrangement of controller / communication circuit components. The PRx device 120 may optionally include other systems and components, such as a communications ("comms") module 128. In some embodiments, the communications module 128 can communicate with a corresponding module in the PTx via a power transmission coil. In other embodiments, the communications module 128 can communicate with a corresponding module or tag using a separate physical channel 138.

[0031] Numerous modifications and extensions are possible for the wireless power transmission system 100 described above, and the following teachings are applicable to any of these modifications and extensions.

[0032] In wireless power transmission applications, a PTx may estimate or calculate the coupling coefficient (denoted "k") between the PTx and the PRx. The coupling coefficient k is a magnetic circuit characteristic that at least partially depends on the relative position / alignment between the PTx and PRx coils and can be used to estimate or calculate the maximum amount of power that the PTx can supply to the PRx. k estimation can be performed by the PTx, for example, by the PTx's controller and communication circuitry, as part of the "digital ping" that occurs at the start of the power transmission process. In some cases, the k estimation procedure can be error-prone, examples of which are described in more detail below. It may be desirable for the PTx and / or PRx to correct the causes of such errors to enable more accurate k estimation, thereby providing a better wireless power transmission experience.

[0033] Figure 2 shows a flowchart 200 of a technique for handling errors in the k estimation process of a wireless power transmission system including a PTx and PRx as described above with reference to Figure 1. The process may be used as part of establishing wireless power transmission in accordance with a standard protocol such as the Qi Wireless Power Transmission Standard published by the Wireless Power Consortium, or in accordance with a proprietary wireless power transmission protocol. The technique described herein is described with reference to the Qi Wireless Power Transmission Standard, but in specific applications, equivalent or corresponding features of a proprietary protocol may be substituted. As part of the PTx estimating k, errors may occur, for example, in the “digital ping” phase of wireless power transmission initiation. Examples of such errors are described in more detail below with reference to Figure 3. In any case, in block 201, the PTx can determine a “mode” for the k estimation error handling process. A first mode, described herein as a “restricted” mode, may be applied when the PRx cannot assist in resolving the error condition. For example, this could be because the PRx device has a completely depleted battery and therefore may not be able to operate adequately when wireless power transmission is to be initiated. Other causes of such a condition are also possible. In any case, in limited mode, the PTx will attempt to resolve the error condition itself, as described in more detail below and shown on the right side of flowchart 200. A second mode, described herein as “full” mode, can be applied when the PRx is potentially capable of assisting in resolving the error condition. In any case, in full mode, the PTx communicates with the PRx as described in more detail below in an attempt to resolve the error condition. In some cases, this cooperation can resolve the error condition, as shown on the left side of flowchart 200. Otherwise, in some cases, the cooperation between the PTx and the PRx may not be successful in resolving the error condition, in which case the PTx may transition to operation similar to limited mode, as described in more detail below.

[0034] Returning to block 201 of flowchart 200, if the PTx determines that it cannot help the PRx resolve the error condition resulting in a k-estimation error, the PTx can remove the power signal (block 202) and effectively reset the wireless power link. Then, in block 203, the PTx can perform one or more corrective actions in an attempt to correct the error condition. Examples of these activities (indicated as "B") in Figures 2 and 3 are described in more detail below. After attempting to correct the error condition, the PTx can retry the digital ping, including making another k-estimation attempt (block 204). If the subsequent k-estimation is successful, the wireless power transmission can proceed normally according to the standard or proprietary protocol. Otherwise, if the error condition still exists, the process in Figure 2 can repeat attempts to resolve the new or continuing error condition. As shown in block 204 of Figure 2, the digital ping is described as occurring at a frequency of 128 kHz, corresponding to at least some versions of the Qi wireless power transmission standard. However, digital ping may be performed at any other suitable frequency according to an appropriate standard or proprietary protocol, and therefore the techniques described herein should not be understood as being limited to any particular operating frequency.

[0035] Returning to block 201 of flowchart 200, if PTx determines that it may be able to assist PRx in resolving an error condition resulting in a K estimation error, PTx may proceed to the “Negotiating with Error Phase” in block 205. For example, this determination may be based on PRx sending its XID (Extended Identification) packet and setting the restriction field in the XID packet to 1 in restriction mode. As shown in block 205 of Figure 2, the Negotiating with Error Phase is described as occurring at a frequency of 128 kHz, corresponding to at least some versions of the Qi Wireless Power Transmission Standard. However, the Negotiating with Error Phase may take place at any other suitable frequency according to the appropriate standard or proprietary protocol, and therefore the techniques described herein should not be understood as being limited to any particular operating frequency. In any case, PTx may then communicate with PRx and negotiate the wireless power transmission link, which may include communication requesting PRx to assist in clearing the error (block 206). Examples of these activities (indicated as "A") in Figures 2 and 3 are described in more detail below. These and other activities described herein as being performed by PRx may be performed by the control and communication circuits of PRx as described above with reference to Figure 1. Next, in block 207, PTx and / or PRx can determine whether the error condition has been cleared. If so, power transmission negotiation and wireless power transmission may proceed as normal. Otherwise, if the cooperation between PTx and PRx fails to clear the error condition, PRx may request the termination of the negotiation phase (block 208), and PTx may proceed as described above with respect to the restricted mode, starting with PTx removing the power signal (block 202), resetting the wireless power transmission link, and otherwise proceeding as in the restricted mode described above.

[0036] Figure 3 shows Table 300 of potential k-estimation error sources and solutions. The first column 331 of Table 300 lists exemplary reasons for k-estimation errors. This list is not exhaustive, and other potential reasons may exist. The second column 332 of Table 300 lists potential actions that PRx may take (indicated by "A" corresponding to block 206 in Figure 2 above) to help resolve the error state. For some error states, there may be no action that PRx can take to resolve the error. The third column 333 of Table 300 lists potential actions that PTx may take to resolve the error state, either in cooperation with PRx or on its own.

[0037] As shown by the first row of Table 300, the k estimation error can be caused by a measurement error. This could be a timing error, i.e., an unexpected out-of-range value measured by PTx during the k estimation phase of the digital ping or any other k estimation phase. In this case, there is no action that PRx can take to resolve the condition, and the PTx action is to retry the digital ping, which results in a transition via block 208 as described above with reference to Figure 2.

[0038] As shown by the second row of Table 300, a k-estimation error can be caused by using a digital ping level that does not enable k-estimation. That is, different voltage levels may be used for the digital ping in different embodiments of wireless power transmission. For example, a half-bridge low voltage of about 11.5 V (indicated as HB_L in the drawings of this application) may be used, corresponding to the inverter voltage applied to the wireless power transmission coil by the PTx, and the PTx may be configured to use such a voltage with the k-estimation technique. Alternatively, a half-bridge high voltage of about 13 V (indicated as HB_H in the drawings of this application) may be used, corresponding to the inverter voltage applied to the wireless power transmission coil by the PTx, and the PTx may not be configured to use such a voltage with the k-estimation technique. In this case, there is nothing the PRx can do to resolve the error condition, and the PTx action is to change to a different digital ping level that enables k-estimation (e.g., HB_L) and retry the digital ping, which will result in a transition via block 208, as described above with reference to Figure 2.

[0039] As shown in the third row of Table 300, k estimation errors can be caused by digital ping levels that require ecosystem scaling factors to be provided to PTx by PRx. For example, PTx may have the necessary information, such as scaling factors, about PRx to perform a successful k estimation at one digital ping voltage, e.g., HB_L, but not the necessary information about PRx to perform a successful k estimation at another digital ping voltage, e.g., HB_H. The same situation can apply to digital pings performed at different frequencies, etc. In either case, if the PRx device can provide scaling factors to PTx, PRx can help clear k estimation errors by providing such factors to PTx. PTx can then retry the digital ping with the newly received ecosystem scaling factors and / or at different digital ping voltages (or frequencies, etc.), which may include power mode changes.

[0040] Ecosystem scaling enables the determination of various electrical and magnetic parameters of a wireless power transmission link by exchanging coefficients that allow for the conversion of measured characteristics, such as between two specific devices, so that PTx and PRx match a model determined with respect to a corresponding reference device. Details of the ecosystem scaling system and parameters are beyond the scope of this disclosure, but an example can be found in the applicant's concurrently pending U.S. Patent Application No. 17 / 681,363, filed February 25, 2022, entitled “Wireless Power Systems with Shared Inductive-Loss Scaling Factors”.

[0041] Figure 4 shows an exemplary communication flow 400 between a PTx and a PRx using the k estimated error handling process in restricted mode, as described above with reference to Figure 2. As described above, restricted mode may be used when the PRx is unable to assist in resolving the k estimated error condition. Throughout Figure 4 (and the subsequent Figures 5 and 6), messages or packets sent from the PRx to the PTx are shown in white, and messages or packets sent from the PTx to the PRx are shown in black. In 1, a digital ping process may be initiated by the PTx, which may enable the PRx to provide one or more initial messages 440, 441. According to at least some versions of the Qi standard, this may include a signal strength (SIG) packet and an identification (ID) packet. This may also trigger the PRx to measure Vrect (the output voltage of the rectifier described above with reference to Figure 1) and Vinv (the inverter voltage applied by the PTx to the wireless power transmitter coil). The PRx may then send an extended identification (XID) packet 442 to the PTx, which may include the measured Vrect value. PTx can then use this Vrect value received from PRx, along with the Vinv value measured by PTx, to calculate the corresponding estimates of the voltage conversion gain and coupling coefficient k.

[0042] If the PTx determines that it cannot estimate k (which may be due to one of the reasons mentioned above, see Figure 3, or for other reasons), the PTx may, in step 2, remove the power signal (see also block 202 in Figure 2), and in step 3, perform one or more corrective actions (see also block 203 in Figure 2). This may include selecting a different digital ping level, changing the power mode, etc. Then, in step 4, the PTx may resume digital ping, which may result in continued operation in restricted mode or a transition to full mode, as will be described in more detail below.

[0043] Figure 5 shows an exemplary communication flow 500 between PTx and PRx using a k estimated error handling process in a first full-mode scenario, which can help PRx resolve an error condition, as described above with reference to Figure 2. Throughout Figure 5 (and the subsequent Figure 6), messages or packets sent from PRx to PTx are shown in white, and messages or packets sent from PTx to PRx are shown in black. In 1, a digital ping process may be initiated by PTx, which may enable PRx to provide one or more initial messages 540, 541. According to at least some versions of the Qi standard, this may include a signal strength (SIG) packet and an identification (ID) packet. This may also trigger PRx to measure Vrect (the output voltage of the rectifier described above with reference to Figure 1) and Vinv (the inverter voltage applied by PTx to the wireless power transmitter coil). Subsequently, PRx may send an extended identification (XID) packet 542 to PTx, which may include the measured Vrect value. PTx can then use this Vrect value received from PRx, along with the Vinv value measured by PTx, to calculate the corresponding estimates of the voltage conversion gain and coupling coefficient k.

[0044] If PTx determines that it cannot estimate k (which may be due to one of the reasons mentioned above with reference to Figure 3, or for other reasons), then PTx may, in step 2, respond to the subsequent Configuration (CFG) packet 543 from PRx with a Negative Response (NAK) packet 544, which triggers the "Negotiate with Error" phase, as described above with reference to block 205 in Figure 2. Then, in step 3, PRx may send a Get (GET) packet 545 requesting an error code from PTx, which PTx may provide in an Error (ERR) packet 546, an example of which is described below. For example, the error packet 546 may indicate that the k estimation error was due to a missing ecosystem scaling factor. Then, in step 4, PRx may send a Kest Estimation Factor (KEST-COEFF) packet 547 to PTx, which may be PRx's contribution to clearing the error condition. Next, PTx may send an acknowledgment (ACK) packet 548 to indicate receipt of the coefficient, or otherwise acknowledge PRx's contribution to clearing the error condition.

[0045] Next, in step 5, PRx may send a further GET packet 549 requesting any further error codes. PTx may then send a response error (ERR) packet 550 indicating any additional or further error conditions, or indicating that no error conditions exist. If no additional or further error conditions exist, in step 6, PRx may send a frequency selection (SRQ / freqsel) packet 551 to initiate a transition to operation at a different frequency, e.g., 360 kHz. This may be acknowledged by PTx sending an acknowledgment (ACK) packet 552. PRx may then send a negotiation complete packet (SRQ / en) packet 553, which may also be acknowledged by PTx (554), and PRx then sends an EPT re-ping packet (EPT / rep) 555, followed by an optional transition to the new operating frequency. This frequency transition is optional and / or may be performed according to some version of the standard protocol or proprietary protocol. In other embodiments or applications, operation may continue at the original frequency (which may be 128 kHz, but is not required). In such cases, PRx and PTx can otherwise complete the negotiation process for wireless power transmission operation using any desired parameters such as frequency, voltage, and power level.

[0046] Figure 6 shows an exemplary communication flow between PTx and PRx using the k estimated error handling process in a second full-mode scenario where PRx cannot help resolve the error condition, as described above with reference to Figure 2. Throughout Figure 6, messages or packets sent from PRx to PTx are shown in white, and messages or packets sent from PTx to PRx are shown in black. In 1, a digital ping process may be initiated by PTx, which may enable PRx to provide one or more initial messages 640, 641. According to at least some versions of the Qi standard, this may include a signal strength (SIG) packet and an identification (ID) packet. This may also trigger PRx to measure Vrect (the output voltage of the rectifier described above with reference to Figure 1) and Vinv (the inverter voltage applied by PTx to the wireless power transmitter coil). Subsequently, PRx may send an extended identification (XID) packet 642 to PTx, which may include the measured Vrect value. PTx can then use this Vrect value received from PRx, along with the Vinv value measured by PTx, to calculate the corresponding estimates of the voltage conversion gain and coupling coefficient k.

[0047] If PTx determines that it cannot estimate k (which may be due to one of the reasons mentioned above with reference to Figure 3, or for other reasons), then PTx may, in step 2, respond to the subsequent Configuration (CFG) packet 643 from PRx with a Negative Response (NAK) packet 644, which triggers the "Negotiate with Error" phase, as described above with reference to block 205 in Figure 2. Then, in step 3, PRx may send a Get (GET) packet 645 requesting an error code from PTx, which PTx may provide in an Error (ERR) packet 646, an example of which is described below. For example, the error packet 646 may indicate that the k estimation error was due to the digital ping level. Upon receiving this error packet, PRx may determine that it cannot help correct this error, and therefore, in step 4, PRx may send an EPT Reset (EPT / rst) packet 647 to PTx, thereby ending the negotiation phase and allowing PTx to attempt to resolve the k estimation error itself, as described above. This then allows for further digital ping techniques to be applied in step 5, resulting in iterations of k estimation, etc.

[0048] Next, in step 5, PRx may send a further GET packet 549 requesting any further error codes. PTx may then send an ERR packet 550 indicating any additional or further error conditions, potentially providing information that would allow the error to be cleared, or indicating that no error conditions exist. If no additional or further error conditions exist, in step 6, PRx may send a frequency selection (SRQ / freqsel) packet 551 to initiate a transition to operation at a different frequency, e.g., 360 kHz. This may be acknowledged by PTx sending an ACK packet 552. PRx may then send a negotiation complete packet (SQQ / en) packet 553, which may also be acknowledged by PTx (554), and PRx then sends an EPT re-ping packet (EPT / rep) 555, followed by an optional transition to the new operating frequency. This frequency transition is optional and / or may be performed according to some version of a standard or proprietary protocol. In other embodiments or applications, operation may continue at the original frequency (which may be but does not have to be 128 kHz). In such cases, PRx and PTx can otherwise complete the negotiation process for wireless power transmission operation using any desired parameters such as frequency, voltage, and power level.

[0049] Figure 7 shows an exemplary data packet structure 700 for exchanging ecosystem scaling factors between PTx and PRx. The data packet structure may be used with a version of the Qi standard or with a proprietary wireless power transmission protocol. In one embodiment, packet 761 may contain 5 bytes (B0-B4), each containing 8 bits (b0-b7). One or more bits (e.g., bits b1-b7 of byte B0) may be reserved for other purposes and / or future use. One bit (e.g., bit b0 of byte B0) may be used as a selector bit. As shown in Table 763, a selector bit value of 0 may be used to indicate that the packet contains a k-estimate of a high-voltage digital ping, and a selector bit value of zero may be a reserved / disallowed value.

[0050] One byte of packet 761 (e.g., byte B1) may be used to provide a first ecosystem scaling parameter (e.g., alpha 0), and another byte of packet 761 (e.g., byte B2) may be used to provide a second ecosystem scaling parameter (e.g., alpha 1). As shown in Tables 764 and 765, each parameter field of packet 761 uses 7 bits, and each parameter can be encoded using a single bit of each byte reserved as a selector. In other cases, all 8 bits can be used to encode individual parameters. Unused bits and / or reserved bits of packet 761, e.g., the reserved bit of byte B0 and unused bytes B3 and B4, may be set to zero.

[0051] Figure 8 shows an exemplary data packet structure 800 for exchanging error information between a PTx and a PRx. The data packet structure may be used with a version of the Qi standard or with a proprietary wireless power transmission protocol. In one embodiment, packet 866 may contain one byte (B0) having 8 bits (b0-b7). Two bits (e.g., bits b0-b1) may be used for error indication. As shown in Table 867, a value of 0 (i.e., binary 00) for the error bits can indicate no error, and a value of 1 (i.e., binary 01) may be used to indicate an error that cannot be performed. Other values ​​(e.g., 2, binary 10, or 3, binary 11) may be reserved. Three bits (e.g., bits b2-b4) of byte B0 of packet 866 are reserved, and three bits (e.g., bits b5-b7) may be used as information bits. As shown in Table 868, an information value of 0 (i.e., binary 000) can be used to indicate no error when the error value is 0, or an error when the error value is 1, indicating that the PTx is unable to successfully perform the k estimation due to the digital ping level. Similarly, an information value of 1 (i.e., binary 001) can be used with an error value of 1 to indicate that the PTx is unable to successfully perform the k estimation due to a missing ecosystem scaling factor. An information value of 2 (i.e., binary 010) can be used to indicate that the PTx is unable to successfully perform the k estimation due to a measurement error. Information values ​​greater than 2 (i.e., binary values ​​011, 100, 101, 110, and 111) may be reserved. Unused and / or reserved bits of packet 866 may be set to zero.

[0052] Various features and embodiments relating to wireless power transmission techniques that address errors in the coupling coefficient estimation process performed when initiating wireless power transmission between PTx and PRx are described above. Such configurations can be used in a variety of applications, but may be particularly advantageous when used with electronic devices such as mobile phones, tablet computers, laptops or notebook computers, and accessories such as wireless headphones, styluses, and smartwatches. Furthermore, although numerous specific features and various embodiments have been described, it should be understood that various features and embodiments can be combined in various permutations in a particular implementation unless otherwise stated to be mutually exclusive. Thus, the various embodiments described above are provided for illustrative purposes only and should not be construed as constituting the scope of this disclosure. Various modifications and changes can be made to the principles and embodiments herein without departing from the scope of this disclosure or the claims.

[0053] The above describes an exemplary embodiment of a wireless power transmission system that can transmit specific information between a PTx and a PRx within a system. This disclosure intends to improve the ability of devices to provide wireless power signals to each other in an efficient manner to facilitate battery charging, for example, by sharing the power processing capabilities of the devices with each other. Entities implementing this technology should take care to ensure that well-established privacy policies and / or privacy practices are adhered to to the extent that any sensitive information is used in a particular implementation. 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 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 a user when they place a device on a power transmitter if the power transmitter is configured to poll for sensitive information from a power receiver.

Claims

1. A method for handling k estimation errors in a wireless power transmission system including a wireless power transmitter and a wireless power receiver, wherein the method is performed by the wireless power transmitter. Performing k estimation during the digital ping phase of wireless power transmission negotiation, It is determined that an error occurred while performing k estimation, Determining whether the wireless power receiver is available to assist in correcting the error, An error occurs while k estimation is being performed, and in response to a determination that the wireless power receiver is available to assist in correcting the error, the wireless power transmitter performs a full-mode error correction procedure in cooperation with the wireless power receiver to correct the error that occurred during k estimation, A method comprising: an error occurring while performing k estimation, and in response to a determination that the wireless power receiver is unavailable to assist in correcting the error, the wireless power transmitter performing a limited-mode error correction procedure in which it attempts to correct the error that occurred during k estimation without cooperation from the wireless power receiver.

2. The method according to claim 1, wherein determining that an error occurred while performing k estimation is based on the wireless power receiver transmitting an extended identification packet having a restriction field set to 1 in the restricted mode.

3. Performing the restricted mode error correction procedure is To remove the power signal and reset the wireless power link, Performing one or more corrective actions, The method according to claim 1, further comprising initiating a further digital ping phase.

4. The method according to claim 3, wherein the one or more corrective actions include initiating further digital ping at a second voltage level different from the first voltage level of the digital ping.

5. Performing a full-mode error correction procedure is Entering a negotiation phase that involves errors, The method according to claim 1, further comprising communicating the error to the wireless power receiver.

6. Communicating the aforementioned error to the wireless power receiver is Sending a negative response (NAK) packet in response to a configuration (CFG) packet from the aforementioned PRx, The method according to claim 5, further comprising transmitting an error (ERR) packet in response to a GET packet from the wireless power receiver.

7. Performing a full-mode error correction procedure is Completing the wireless power transmission negotiation phase in response to receiving information from the wireless power receiver that enables the clearing of the aforementioned error, In response to not receiving information from the wireless power receiver that would allow the error to be cleared, Receiving a request from the wireless power receiver to terminate the negotiation phase, The power signal is removed and the wireless power link is reset. Performing one or more corrective actions, The method according to claim 5, further comprising initiating a further digital ping phase.

8. The method according to claim 7, wherein the additional information received from the wireless power receiver includes an ecosystem scaling factor.

9. The method according to claim 8, wherein the ecosystem scaling coefficient is received in an ecosystem scaling coefficient packet.

10. The method according to claim 7, wherein the information enabling the clearing of the error is included in the EPT / RST packet from the wireless power receiver.

11. A wireless power transmitter comprising control and communication circuits, wherein the control and communication circuits are During the digital ping phase of wireless power transmission negotiation, perform k estimation. It was determined that an error occurred while performing k estimation. Determine whether the wireless power receiver is available to assist in correcting the error. An error occurs while performing k estimation, and in response to a determination that the wireless power receiver is available to assist in correcting the error, the wireless power transmitter performs a full-mode error correction procedure in cooperation with the wireless power receiver to correct the error that occurred during k estimation, and the full-mode error correction procedure is: Entering a negotiation phase that involves errors, This includes communicating the aforementioned error to the wireless power receiver, An error occurs while performing k estimation, and in response to a determination that the wireless power receiver is unavailable to assist in correcting the error, the wireless power transmitter performs a limited mode error correction procedure in which it attempts to correct the error that occurred during k estimation without cooperation from the wireless power receiver, and the limited mode error correction procedure is: To remove the power signal and reset the wireless power link, Performing one or more corrective actions, This includes initiating a further digital ping phase, and a wireless power transmitter.

12. The wireless power transmitter according to claim 11, wherein determining that an error occurred while performing k estimation is based on receiving an extended identification packet having a restriction field set to 1 in the case of restriction mode from the wireless power receiver.

13. The wireless power transmitter according to claim 11, wherein the one or more correction actions include the control and communication circuit initiating further digital ping at a second voltage level different from the first voltage level of the digital ping.

14. Communicating the aforementioned error to the wireless power receiver means that the control and communication circuits, Sending a negative response (NAK) packet in response to a configuration (CFG) packet from the aforementioned PRx, The wireless power transmitter according to claim 11, further comprising transmitting an error (ERR) packet in response to a GET packet from the wireless power receiver.

15. Performing a full-mode error correction procedure is Completing the wireless power transmission negotiation phase in response to receiving from the wireless power receiver information that enables the clearing of the error, which is included in the EPT / RST packet from the wireless power receiver received by the control and communication circuit. In response to not receiving information from the wireless power receiver that would allow the error to be cleared, Receiving a request from the wireless power receiver to terminate the negotiation phase, The power signal is removed and the wireless power link is reset. Performing one or more corrective actions, The wireless power transmitter according to claim 11, further comprising initiating a further digital ping phase.

16. The wireless power transmitter according to claim 15, wherein the additional information received from the wireless power receiver includes an ecosystem scaling factor received in an ecosystem scaling factor packet.

17. A method for handling k estimation errors in a wireless power transmission system including a wireless power transmitter and a wireless power receiver, wherein the method is performed by the wireless power receiver. Receiving an instruction from the wireless power transmitter that an error occurred during the digital ping phase, In the digital ping phase, the cause of the error is received from the wireless power transmitter, In response to the fact that the cause indicated above is an estimation error k and can be corrected by the wireless power receiver, additional information is transmitted to the wireless power transmitter, thereby resolving the error in cooperation with the wireless power transmitter. A method comprising sending a reset message to the wireless power transmitter in response to the fact that the cause described above is uncorrectable by the wireless power receiver, thereby causing the wireless power transmitter to attempt to resolve the error on its own.

18. The method according to claim 17, wherein the additional information includes an extended identification packet having a restriction field set to 1 in the restricted mode.

19. The method according to claim 17, wherein transmitting additional information to the wireless power transmitter, thereby cooperating with the wireless power transmitter to resolve the error, includes transmitting the ecosystem scaling coefficient in the ecosystem scaling coefficient packet.

20. The method according to claim 17, wherein the reset message includes an EPT / RST packet.

21. A wireless power receiver comprising a control and communication circuit, wherein the control and communication circuit is An instruction indicating that an error occurred during the digital ping phase is received from the wireless power transmitter. In the digital ping phase, the cause of the error is received from the wireless power transmitter. In response to the fact that the cause indicated above is an estimation error and can be corrected by the wireless power receiver, additional information is transmitted to the wireless power transmitter, thereby resolving the error in cooperation with the wireless power transmitter. A wireless power receiver that, in response to the fact that the cause described above is uncorrectable by the wireless power receiver, sends a reset message to the wireless power transmitter, thereby causing the wireless power transmitter to attempt to resolve the error itself.

22. The wireless power receiver according to claim 21, wherein the additional information includes an extended identification packet having a restriction field set to 1 in the restricted mode.

23. The wireless power receiver according to claim 21, wherein the additional information includes transmitting the ecosystem scaling coefficient in the ecosystem scaling coefficient packet.

24. The wireless power receiver according to claim 21, wherein the reset message includes an EPT / rst packet.

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