Pulse Width Communication in Wireless Power Systems

Abstract

The present disclosure provides systems, methods, and devices for a new communication technique between a wireless power transmitting device and a wireless power receiving device. The new communication technique may be more efficient for communicating feedback parameters or other control information compared to legacy packet-based digital communication techniques. The new communication technique may use pulse-width modulated (PWM) signals as analog representations of the feedback parameters or other control information. In some implementations, the PWM communication technique of the present disclosure may be used for various control or feedback information from the wireless power receiving device to the wireless power transmitting device. Furthermore, in some implementations, the PWM communication technique may be used for feedforward information from the wireless power transmitting device to the wireless power receiving device.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to wireless power. More specifically, this application relates to communication between a wireless power receiving device and a wireless power transmitting device. [Background technology]

[0002] Wireless power technologies have been developed to allow wireless transmission of power from a wireless power transmitting device to a wireless power receiving device. Examples of wireless power receiving devices may include mobile devices, small electronic devices, computers, tablets, gadgets, appliances (including some types of cordless blenders, kettles, mixers, etc.), and some types of larger electronic devices, among other examples. The wireless power transmitting device may include a primary coil that generates an electromagnetic field. The electromagnetic field can induce a voltage in a secondary coil of the wireless power receiving device when the secondary coil is placed in close proximity to the primary coil. In this configuration, the electromagnetic field can wirelessly transmit power to the secondary coil. The power may be transferred using inductive or resonant coupling between the primary and secondary coils. Wireless power transmission is sometimes referred to as contactless or non-contact power transmission.

[0003] When performing wireless power transmission, the wireless power transmitting device needs to stop power transmission when the wireless power receiving device is removed from the charging area. The wireless power transmitting device can detect the presence of the wireless power receiving device during the transmission of power and enable a change to the operating point of the wireless power signal based on a control signal such as a control error packet. For example, the wireless power transmitting device can detect that the wireless power receiving device has been removed from the charging area when it does not receive a control error packet for a predetermined period of time (e.g., 1.8 seconds). Furthermore, the control error packet may include information that causes the wireless power transmitting device to modify the amount of power, current, voltage, or other parameters. Similarly, the wireless power transmitting device may communicate information to the wireless power receiving device associated with the wireless power transmission. Existing techniques for communication between the wireless power receiving device and the wireless power transmitting device can benefit from improvements. Summary of the Invention

[0004] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0005] One innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless power transmission. In some implementations, the method may be performed by a wireless power transmitting device. The method may include transmitting wireless power to a wireless power receiving device via at least one primary coil. The method may include receiving a pulse width modulated (PWM) signal from the wireless power receiving device. The PWM signal may include one or more pulses. The method may include determining a feedback parameter based on a pulse width of the one or more pulses. The method may include managing a transmission of wireless power from the wireless power transmitting device to the wireless power receiving device based at least in part on the feedback parameter.

[0006] In some implementations, the feedback parameter is a control error value. Managing the transmission of wireless power may include setting an operating point for the transmission of wireless power based at least in part on the control error value.

[0007] In some implementations, the feedback parameter is indicative of a load power. Managing the transmission of wireless power includes determining if a foreign object is detected based on a comparison of the load power to the transmitted amount of wireless power.

[0008] In some embodiments, determining the feedback parameter includes determining a pulse width ratio based on pulse widths of the one or more pulses and converting the pulse width ratio to the feedback parameter based on a predetermined translation.

[0009] In some embodiments, receiving the PWM signal includes receiving a number of pulses occupying respective pulse time slots.

[0010] In some embodiments, the duration of each pulse time slot is 0.5 milliseconds such that a pulse time slot corresponds to a 2 kHz communication clock cycle.

[0011] In some implementations, the PWM signal includes a pulse in every other pulse time slot.

[0012] In some implementations, the one or more pulses include at least a first pulse and a second pulse. A pulse width of the first pulse can indicate a sign of the feedback parameter. A pulse width of the second pulse can indicate a magnitude of the feedback parameter.

[0013] In some implementations, the method may include receiving a start analog control packet prior to receiving the PWM signal, the start analog control packet indicating that the PWM signal follows the start analog control packet.

[0014] In some implementations, the method may include receiving an initiating analog control packet encoded as a differential bi-phase encoded signal.

[0015] In some implementations, the method may include receiving a series of consecutive pulses corresponding to a predetermined pattern of pulse widths and determining that the series of consecutive pulses indicates an end of the PWM signal.

[0016] In some implementations, the method may include receiving a terminated analog control packet or other packet encoded as a differential bi-phase encoded signal after termination of the PWM signal.

[0017] In some implementations, receiving the PWM signal includes receiving the PWM signal via a primary coil.

[0018] In some embodiments, receiving the PWM signal includes receiving the PWM signal via a wireless communication interface separate from the primary coil.

[0019] In some implementations, the wireless communication interface is a short-range radio frequency interface or a short-range wireless communication interface.

[0020] In some implementations, receiving the PWM signal includes detecting a load change during the transmission of wireless power.

[0021] In some implementations, receiving the PWM signal includes activating a PWM communication technique for analog control based on the feedback parameter.

[0022] In some implementations, the method may include, where activating the PWM communication technique includes transmitting a first packet to the wireless power receiving device indicating that the wireless power transmitting device supports the PWM communication technique.

[0023] In some implementations, the method may include receiving a second packet from the wireless powered device indicating that the wireless powered device is activating the PWM communication technique.

[0024] Another innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless power transmission. In some implementations, the method may be performed by a wireless power receiving device. The method may include receiving wireless power from a wireless power transmitting device via at least one secondary coil of the wireless power receiving device. The method may include determining a feedback parameter based on the wireless power, the feedback parameter being for the wireless power transmitting device to manage the transmission of the wireless power. The method may include communicating a pulse width modulated (PWM) signal from the wireless power receiving device to the wireless power transmitting device. The PWM signal may include one or more pulses. Each pulse may have a pulse width based at least in part on the feedback parameter.

[0025] In some implementations, the method may include receiving wireless power after communicating the PWM signal. An operating point of the wireless power transmitting device may be adjusted based on the feedback parameter.

[0026] In some implementations, the feedback parameter is a control error value based on a comparison of a desired control point and an actual control point.

[0027] In some implementations, communicating the PWM signal includes performing load modulation of the wireless power using a communication portion of the wireless power receiving device. The load modulation may be based on a pulse width of each pulse.

[0028] In some implementations, communicating the PWM signal includes performing a communication modulation using a wireless communication interface separate from the at least one secondary coil of the wireless power receiving device. The communication modulation can have one or more pulses in the received or transmitted communication signal.

[0029] In some implementations, the method may include transmitting the PWM signal including periodically determining new feedback parameters and periodically communicating new pulses to the wireless power transmitting device, each new pulse having a corresponding pulse width based on the new feedback parameters.

[0030] In some implementations, transmitting the PWM signal includes converting the feedback parameter to a pulse width ratio based on the predetermined translation and determining a pulse width of the one or more pulses based on the pulse width ratio.

[0031] In some implementations, communicating the PWM signal includes communicating a plurality of pulses, each pulse occupying a respective pulse time slot, each pulse time slot having a duration of 0.5 milliseconds such that the pulse time slot corresponds to a 2 kHz communication clock cycle.

[0032] In some implementations, the PWM signal includes a pulse in every other pulse time slot.

[0033] In some implementations, the method may include communicating a start analog control packet prior to communicating the PWM signal, the start analog control packet indicating that the PWM signal follows the start analog control packet.

[0034] In some implementations, the method may include communicating the initiating analog control packet as a differential bi-phase encoded signal.

[0035] In some implementations, the method may include communicating a series of consecutive pulses corresponding to a predetermined pattern of pulse widths, the series of consecutive pulses may indicate an end of the PWM signal.

[0036] In some implementations, the method may include communicating a terminated analog control packet or other packet encoded as a differential bi-phase encoded signal after termination of the PWM signal.

[0037] In some embodiments, communicating the PWM signal includes communicating the PWM signal through a secondary coil.

[0038] In some embodiments, communicating the PWM signal includes communicating the PWM signal through a wireless communication interface that is separate from the secondary coil.

[0039] In some implementations, the wireless communication interface is a short-range radio frequency interface or a short-range wireless communication interface.

[0040] In some implementations, the method may include activating a PWM communication technique for analog control based on the feedback parameters prior to communicating the PWM signal.

[0041] In some implementations, activating the PWM communication technique includes receiving a first packet from the wireless power transmitting device indicating that the wireless power transmitting device supports the PWM communication technique.

[0042] In some implementations, the method may include communicating a second packet to the wireless power transmitting device indicating that the wireless power receiving device is activating the PWM communication technique.

[0043] Another innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless power transmission. In some implementations, the method may be performed by a wireless power transmitting device. The method may include transmitting wireless power to a wireless power receiving device via at least one primary coil. The method may include determining a message value for communicating with the wireless power receiving device. The method may include determining a pulse width of one or more pulses of a pulse width modulated (PWM) signal based at least in part on the message value. The method may include transmitting a frequency modulated signal from the wireless power transmitting device to the wireless power receiving device based on the pulse width, wherein the frequency modulated signal has a first frequency during an on-time duration of the pulse width. The frequency modulated signal may have a second frequency during a time other than the on-time duration of the pulse width.

[0044] In some embodiments, the message value is an acknowledgement (ACK), a non-acknowledgement (NAK), or an undefined (ND) response.

[0045] In some implementations, if the message value is an ACK, the pulse width may have a first duration, if the message value is a NAK, the pulse width may have a second duration, and if the message value is an ND response, the pulse width may have a third duration.

[0046] In some implementations, the first duration, the second duration, and the third duration are within different ranges defined by a standard technical specification.

[0047] Another innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless power transmission. In some implementations, the method may be performed by a wireless power receiving device. The method may include receiving wireless power from a wireless power transmitting device via at least one secondary coil of the wireless power receiving device. The method may include receiving a frequency modulated signal from the wireless power transmitting device, the frequency modulated signal having one or more pulses according to a PWM signal. The method may include determining a pulse width of the one or more pulses based at least in part on a first frequency of the frequency modulated signal. The frequency modulated signal may have a first frequency during an on-time duration of the pulse width. The frequency modulated signal may have a second frequency during a time other than the on-time duration of the pulse width. The method may include determining a message value based at least in part on the pulse width.

[0048] Another innovative aspect of the subject matter described in this disclosure can be embodied as a wireless power transmitting device. The wireless power transmitting device may include a transmitting coil, a communication unit, and a controller. The transmitting coil, the communication unit, and the controller may be configured to perform any one of the methods described above.

[0049] Another innovative aspect of the subject matter described in this disclosure can be implemented as a wireless power receiving device. The wireless power receiving device may include a transmitting coil, a communication unit, and a controller. The transmitting coil, the communication unit, and the controller may be configured to perform any one of the methods described above.

[0050] Another innovative aspect of the subject matter described in this disclosure can be embodied as a computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform any one of the methods described above.

[0051] Another innovative aspect of the subject matter described in this disclosure can be embodied as a system having means for performing any one of the methods described above.

[0052] Another innovative aspect of the subject matter described in this disclosure can be implemented as an apparatus having one or more processors configured to perform one or more operations from any one of the methods described above. [Brief description of the drawings]

[0053] The details of one or more embodiments of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. It should be noted that the relative dimensions of the following figures may not be drawn to scale.

[0054] [Figure 1] 1 shows a block diagram of an example wireless power system including an example wireless power transmitting device and an example wireless power receiving device.

[0055] [Diagram 2] 1 illustrates a message flow diagram of an exemplary wireless power transmission process.

[0056] [Diagram 3] 1 illustrates an example of a power control process performed between a wireless power transmitting device and a wireless power receiving device.

[0057] [Figure 4] 1 shows a block diagram conceptually illustrating an example control error packet.

[0058] [Diagram 5] FIG. 1 shows a block diagram conceptually illustrating byte encoding.

[0059] [Figure 6] 1 shows a block diagram conceptually illustrating an exemplary wireless power receiving device.

[0060] [Figure 7] 1 shows a signal diagram conceptually illustrating a differential biphase encoding technique for communicating digital signals;

[0061] [Figure 8] 1 shows a timing diagram conceptually illustrating multiple control error packets.

[0062] [Figure 9] 1 shows a signal diagram conceptually illustrating an exemplary pulse width modulation (PWM) communication technique.

[0063] [Figure 10] 4 illustrates an exemplary relationship between a control error value and a pulse width ratio.

[0064] [Figure 11A] 4 illustrates an exemplary calculation for determining a pulse width representative of a control error value.

[0065] [Figure 11B] 4 illustrates an exemplary calculation for determining a control error value based on a pulse.

[0066] [Figure 12A] FIG. 1 shows a timing diagram conceptually illustrating multiple pulse signaling.

[0067] [Figure 12B] 1 shows another timing diagram conceptually illustrating multiple pulse signaling where a pulse occurs in every other pulse time slot.

[0068] [Figure 12C] FIG. 13 shows another timing diagram conceptually illustrating multiple pulse signaling in which a feedback parameter can be encoded into two pulses.

[0069] [Figure 13] 1 shows a timing diagram conceptually illustrating signaling for activating or deactivating a PWM communication technique.

[0070] [Figure 14]1 shows a block diagram conceptually illustrating an example wireless power receiving device capable of using PWM communication techniques over an out-of-band communication channel.

[0071] [Figure 15] 1 shows a flow diagram illustrating an example operation of a process for using PWM communication techniques in a wireless power transmitting device.

[0072] [Figure 16] 1 shows a flow diagram illustrating an example operation of a process for using PWM communication techniques in a wireless powered device.

[0073] [Figure 17] 1 shows a signal diagram conceptually illustrating an example frequency variation based on a PWM communication technique.

[0074] [Figure 18] 1 shows a flow diagram illustrating an example operation of another process for using PWM communication techniques in a wireless power transmitting device.

[0075] [Figure 19] 1 shows a block diagram of an exemplary apparatus for use in a wireless power system.

[0076] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0077] The following description refers to specific implementations for purposes of illustrating the innovative aspects of the present disclosure. However, those skilled in the art will readily recognize that the teachings herein may be applied in many different ways. The described implementations may be implemented in any means, device, system, or method for transmitting or receiving wireless power.

[0078] A conventional wireless power system may include a wireless power transmitting device and a wireless power receiving device. The wireless power transmitting device may include one or more primary coils that transmit wireless energy (as a wireless power signal) to one or more corresponding secondary coils in the wireless power receiving device. The primary coil refers to a source of wireless energy (such as induction or magnetic resonance energy that generates an electromagnetic field) in the wireless power transmitting device. The secondary coil located in the wireless power receiving device can receive the wireless energy via the electromagnetic field. The transmission of wireless power may be controlled by a signal such as a control error packet (CEP) from the wireless power receiving device to the wireless power transmitting device. The wireless power transmitting device may periodically check whether it has received a CEP within a predetermined period of time and control or stop the transmission of wireless power based on the CEP. Conventional techniques for CEP have been useful for low power or low speed wireless power systems. However, as wireless power systems increase power levels and attempt to reduce the time between adjustments, conventional techniques for CEP may be inadequate due to delays or communication inefficiencies. For brevity, some examples of the present disclosure describe communication of a control error value that would otherwise be communicated in a CEP. Although the examples of this disclosure relate to control signals of control error values ​​transmitted from a wireless power receiving device to a wireless power transmitting device, the communication techniques of this disclosure can be used for other types of control or feedback information from a wireless power receiving device to a wireless power transmitting device. Additionally, in some implementations, the communication techniques can be used for feedforward information from a wireless power transmitting device to a wireless power receiving device.

[0079] The present disclosure provides systems, methods, and devices for wireless power transmission and reception. Various embodiments generally relate to communication between a wireless power transmitting device and a wireless power receiving device. In some implementations, the communication techniques in the present disclosure can be used as more efficient communication of feedback or feedforward parameters compared to conventional techniques using packet-based digital communication. In some implementations, the wireless power receiving device may communicate a feedback parameter to indicate the ongoing presence of the wireless power receiving device or to cause the wireless power transmitting device to adjust its operating point for the transmission of wireless power. For example, the feedback parameter may be a control error value. The control error value may be more efficiently communicated using an analog representation rather than communicating as a packet-based digital communication. In some implementations, a pulse width modulation (PWM) communication technique may include a variable size pulse width to represent and communicate the feedback parameter. For example, the pulse width size may indicate a magnitude or other information regarding the feedback parameter.

[0080] PWM communication techniques can vary the pulse width of a single pulse within a given pulse time slot. Each pulse may have an "on-time" duration during the pulse time slot, and the on-time duration is different from the "off-time" during the pulse time slot. The on-time of a pulse may have a predetermined amplitude or a predetermined signal frequency to distinguish it from the off-time. Pulse width (also called pulse duration, pulse length, or pulse size) can refer to the on-time duration of a pulse within a pulse time slot. Pulse width ratio is a numerical expression that refers to the ratio of the pulse width (on-time duration of a pulse) to the duration of the pulse time slot. Pulse width ratio may also be referred to as the duty cycle or duty ratio associated with a single pulse within a pulse time slot. A PWM signal (also called a pulse train) can include multiple pulses.

[0081] According to examples of the present disclosure, the pulse width (and thus the pulse width ratio) of the pulses can be indicative of a feedback parameter. For example, the pulse width ratio can be indicative of a magnitude or value (such as a control error value) of the feedback parameter. In some implementations, the pulse widths may be based on a predetermined relationship between different pulse widths and corresponding values ​​of the feedback parameter. The wireless power receiving device can control a PWM modulator or switch to generate pulses having specific pulse widths such that a pulse width ratio of the pulse widths in a pulse time slot is indicative of the feedback parameter. The wireless power transmitting device can sense the pulse width of the pulses and determine the pulse width ratio for the pulse time slot. The wireless power transmitting device can determine the feedback parameter based on the pulse width ratio. In examples where the feedback parameter is a control error value, a pulse width ratio associated with a single pulse can be indicative of the control error value. In some implementations, the PWM signal may include multiple pulses and the pulse width ratio associated with each pulse may communicate a control error value. Thus, changes in the control error value may be communicated frequently and quickly, allowing the wireless power transmitting system to adapt to changes in the environment or power requirements.

[0082] Conventional communication techniques can communicate digital information using amplitude shift key (ASK) modulation or frequency shift key (FSK) modulation. Conventional wireless power transmission systems can encode digital information for ASK transmission or FSK transmission. For example, conventional wireless power receiving devices can encode a control error value in a CEP for ASK transmission. The CEP may include at least 44 bits of digital information for a single control error value. In a typical wireless power system, the ASK transmission may be signaled according to a frequency of 2 kilohertz (kHz). Thus, each bit of digital information may take 0.5 milliseconds (ms) to communicate using conventional communication techniques based on ASK modulation. To communicate a CEP with 44 bits of digital information as ASK modulation in conventional communication techniques, the wireless power transmission system requires at least 22 ms (44 bits x 0.5 ms / bit) to communicate a single control error value. In contrast, the PWM communication technique of the present disclosure can communicate a control error value as a variable size pulse occurring during a single pulse time slot of 0.5 ms. The 0.5 ms pulse time slots can be aligned with the 2 kHz frequency that would otherwise be used for conventional communication techniques. The variable size pulse widths of the pulses within the pulse time slots allow a complete analog value, rather than a single bit of information, to be conveyed using conventional communication techniques.

[0083] In some implementations, the PWM communication technique may be referred to as analog control feedback (or analog control). The analog control feedback may approximate the speed of a wired control line due to the efficiency of PWM for communicating control error values ​​or other feedback parameters. In some embodiments, the communication protocol between the wireless power receiving device and the wireless power transmitting device may be adapted to support dynamic enabling or disabling of the analog control. For example, a start analog control packet may be signaled using conventional ASK modulation or FSK modulation. The start analog control packet may signal the enablement of the PWM communication technique to communicate analog control information. The analog control information may then be communicated using the PWM communication technique instead of the ASK modulation or FSK modulation. A predetermined pattern of PWM signaling may indicate the end of the analog control so that both the wireless power receiving device and the wireless power transmitting device can revert to conventional ASK modulation or FSK modulation for digital communication.

[0084] In some implementations, the PWM communication technique can be implemented using existing hardware of a conventional wireless power receiving device or a conventional wireless power transmitting device. For example, the communication section of the wireless power receiving device may have a modulation switch capable of implementing ASK based on a switch control line from a controller. To implement the PWM communication technique, the controller may control one or more of the modulation switches according to a desired pulse width in a pulse time slot. Thus, in some implementations, the PWM communication technique can be implemented in an existing system with minor modifications.

[0085] In some implementations, the pulse widths of various pulses in the PWM signal can indicate different components or values ​​of the feedback parameter. For example, some pulses (having a selected one of a plurality of predetermined pulse widths) can indicate a positive or negative sign of the control error value. Other pulses (having variable pulse widths) can indicate a magnitude of the control error value. In some implementations, each pulse in a set of pulse time slots can indicate a different analog component of the feedback parameter. For example, a first pulse can indicate a coarse value and a second pulse can indicate a fine value. Additionally or alternatively, each pulse in a set of consecutive pulses can indicate an offset value for fine grain adjustment relative to a value communicated to one or more previous pulses in the set of consecutive pulses.

[0086] Many of the examples in this disclosure are based on a control error value communicated by the wireless power receiving device to the wireless power transmitting device using PWM communication techniques. The control error value may be used for control signaling, and the wireless power transmitting device may set an operating point based on the control signaling. However, other types of feedback parameters may also be communicated for different use cases. For example, another use case is foreign object detection (FOD). The feedback parameter may be a load power, a rectified voltage level, a quality factor, a quality measurement, or some indicator related to wireless power transmission efficiency. The wireless power transmitting device may use the feedback parameter to determine an alignment of the transmitting coil or detect whether a foreign object is near the transmitting coil. The wireless power transmitting device may compare the feedback parameter to the amount of wireless power transmitted during the initiation of a ping signal or wireless power signal to determine wireless power transmission efficiency. If the wireless power transmission efficiency is below a threshold, the wireless power transmitting device may determine that a foreign object is detected.

[0087] Certain implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. Thus, the PWM communication techniques of the present disclosure can communicate the control error value (or other feedback parameters) in analog form, allowing for much faster communication of the control error value compared to conventional communication techniques. Efficient communication of control information allows for better user experience and faster control of the wireless power transmission system. The communication techniques in the present disclosure can eliminate or reduce packet or bit coding overhead associated with conventional communication techniques. Thus, the PWM communication techniques can avoid or reduce delays associated with conventional feedback mechanisms. Also, the wireless power receiving device can be more responsive to changes in load or position. In high-power wireless power systems, the use of efficient communication techniques (such as those described herein) can prevent failures, overheating, or degradation of charge that would otherwise occur with conventional communication techniques.

[0088] FIG. 1 illustrates a block diagram of an exemplary wireless power system 100 including an exemplary wireless power transmitting device 102 and an exemplary wireless power receiving device 118. The wireless power transmitting device includes a primary coil 104. The primary coil 104 may be associated with a power signal generator 106. The primary coil 104 may be a wire coil that transmits wireless power (sometimes referred to as wireless energy). The primary coil 104 may transmit wireless energy using an induction or magnetic resonance field. The power signal generator 106 may include components (not shown) that provide power to the primary coil 104 and cause the primary coil 104 to generate a wireless power signal. For example, the power signal generator 106 may include one or more switches, drivers, series capacitors, rectifiers, or other components. The wireless power transmitting device 102 may also include a transmission controller 108 that controls the components of the power signal generator 106. For example, the transmission controller 108 can determine an operating point (such as a voltage or current) and control the power signal generator 106 according to the operating point.

[0089] In some implementations, the power signal generator 106, the transmission controller 108, and other components (not shown) may be collectively referred to as a power transmitting circuit 110. Some or all of the power transmitting circuit 110 may be embodied as an integrated circuit (IC) that implements features of the present disclosure for controlling and transmitting wireless power to one or more wireless power receiving devices. The transmission controller 108 may be implemented as a microcontroller, a special purpose processor, an integrated circuit, an application specific integrated circuit (ASIC), or any other suitable electronic device.

[0090] The power source 112 can provide power to the power transmission circuitry 110 in the wireless power transmitting device 102. The power source 112 can convert alternating current (AC) power to direct current (DC) power. For example, the power source 112 may include a converter that receives AC power from an external power source and converts the AC power to DC power used by the power signal generator 106.

[0091] The first communication unit 142 may be coupled to components of the power signal generator 106 or the primary coil 104 to transmit and receive communications via the wireless power signal. The first communication unit 142 may include logic for controlling one or more switches and other components that cause the transmission and reception of wireless signals via the wireless power signal. For example, the first communication unit 142 may include a modulator or demodulator that converts information into an ASK or FSK modulated signal. In one example, the first communication unit 142 may convert data from the transmission controller 108 into an FSK modulated signal that is combined with the wireless power signal for communication from the wireless power transmitting device 102 to the wireless power receiving device 118. In another example, the first communication unit 142 may sense a load modulated ASK signal from the power signal generator 106 or the primary coil 104 and demodulate the ASK signal to obtain the data that the first communication unit 142 provides to the transmission controller 108.

[0092] In some embodiments, the wireless power transmitting device 102 may include a wireless communication interface 114. The wireless communication interface 114 may be connected to a first communication coil 116 (which may be a coil or a loop antenna). The wireless communication interface 114 may include logic for controlling one or more switches and other components that cause the transmission and reception of wireless communication signals through the first communication coil 116. In some implementations, the wireless communication interface 114 may support short-range radio frequency communication (such as Bluetooth™) or near field communication (NFC). NFC is a technology that transfers data at a carrier frequency of 13.56 MHz. The wireless communication unit 124 may also support any suitable communication protocol.

[0093] The transmission controller 108 may detect the presence or proximity of the wireless powered device 118. In some implementations, the presence or proximity of the wireless powered device 118 may be detected based on a load change in response to a periodic low power signal generated by the power signal generator 106 and the primary coil 104. In some implementations, the presence or proximity of the wireless powered device 118 may occur during a periodic ping process of the wireless communication interface 114 in the wireless power transmitting device 102. The transmission controller 108 may receive a signal strength packet from the wireless powered device 118. The signal strength packet may indicate a rectified value of the received voltage. The transmission controller 108 may use this voltage value to check the quality of the coupling between the transmitter coil and the receiving coil and decide whether to continue providing power.

[0094] The transmission controller 108 may control characteristics of the wireless power that the wireless power transmitting device 102 provides to the wireless power receiving device 118. After detecting the wireless power receiving device 118, the transmission controller 108 may receive information from the wireless power receiving device 118. For example, the transmission controller 108 may receive information during a handshake process with the wireless power receiving device 118. The information may include information about the wireless power receiving device 118 (such as power rating, manufacturer, and model, among other examples). The transmission controller 108 can use this information to determine at least one operational control parameter (e.g., frequency, duty cycle, voltage, etc.) for the wireless power it provides to the wireless power receiving device 118. To configure the wireless power, the transmission controller 108 can modify the frequency, duty cycle, voltage, or any other suitable characteristic of the power signal generator 106.

[0095] The wireless powered device 118 may include a secondary coil 120, a rectifier 126, and a receiver controller 128. When the secondary coil 120 is aligned with the primary coil 104, the secondary coil 120 may generate an induced voltage based on the wireless power signal received from the primary coil 104. A capacitor may be in series between the secondary coil 120 and the rectifier 126. The rectifier 126 may rectify the induced voltage and provide the induced voltage to a load 130. In some implementations, the load 130 may be external to the wireless powered device 118 and coupled via a wire from the rectifier 126. Some implementations may include a series switch (not shown in FIG. 1 ) between the rectifier 126 and the load 130 that can disconnect the load 130 from the rectifier 126.

[0096] The receiver controller 128 may be connected to the rectifier 126 and the second communication unit 152. The second communication unit 152 may be coupled to components of the secondary coil 120 or the rectifier 126 to transmit and receive communications via the wireless power signal. The second communication unit 152 may include logic for controlling one or more switches and other components that cause the transmission and reception of communication signals via the wireless power signal. For example, the second communication unit 152 may include a modulator or demodulator that converts information into an ASK or FSK modulated signal. In one example, the second communication unit 152 may convert data from the receiver controller 128 into an ASK modulated signal that is used to load modulate the wireless power signal for communication from the wireless power receiving device 118 to the wireless power transmitting device 102. In another example, the second communication unit 152 may sense the FSK signal in the wireless power signal at the secondary coil 120 or the rectifier 126 and demodulate the FSK signal to obtain the data that the second communication unit 152 provides to the receiver controller 128.

[0097] In some embodiments, the wireless power receiving device 118 may include a wireless communication interface 132. The wireless communication interface 132 may include modulation and demodulation circuitry for wireless communication via a second communication coil 134 (which may be a coil or a loop antenna). Thus, the receiver controller 128 may wirelessly communicate with the transmission controller 108 via the wireless communication interface 132 and the wireless communication interface 114 using NFC communication. The receiver controller 128 and the transmission controller 108 use the communication to form a feedback control loop (e.g., the power control process 300 described with reference to FIG. 3). The receiver controller 128 may provide feedback to the transmission controller 108 (via any of the communication paths described herein), and the transmission controller 108 may adjust the operating point of the wireless power signal based on the feedback.

[0098] In some conventional wireless power systems, the primary coil can transmit wireless energy to the secondary coil up to a rating prescribed by the wireless standard. For example, a low-power wireless power signal can transmit five watts (5W), 9W, 12W, or 15W. Low-power wireless power systems can deliver up to 15W of energy, suitable for many electronic devices. Higher-power wireless systems are being developed to support wireless power transmission to electronic devices that require more power. For example, medium and high wireless power systems can deliver wireless power in excess of 15W. Wireless power systems can benefit from improved communication and control as the power ratings of wireless power transmission systems continue to increase.

[0099] FIG. 2 shows a message flow diagram of an exemplary wireless power transmission process. Referring to FIG. 2, the wireless power transmitting device detects that the wireless power receiving device is located in a charging area in standby mode (S200). There are various methods for the wireless power transmitting device to detect the wireless power receiving device, and the method is not limited to a specific method in the present disclosure. As an example, the wireless power transmitting device may detect that the wireless power receiving device is located in the charging area by periodically transmitting an analog ping of a specific frequency, and detect a resonance shift or a capacitance change based on the detection current. As another example, the wireless power transmitting device may periodically transmit a detection signal, and the wireless power receiving device may transmit a response signal (e.g., a control error packet or a signal strength packet). The wireless power transmitting device may detect that the wireless power receiving device is located in the charging area based on receiving the response signal within a predetermined time following the detection signal. As yet another example, the wireless power receiving device may transmit a search signal or an advertisement signal to the wireless power transmitting device. The search signal or advertisement signal may be conventionally transmitted using short-range radio frequency communication (such as Bluetooth (trademark)). The wireless power transmitting device may detect the wireless power receiving device based on receiving the search signal or the advertisement signal.

[0100] In some implementations, as a preparation step for wireless power transmission, the wireless power transmitting device may optionally transmit an information request signal to the wireless power receiving device (S210). The information request signal may be a signal requesting the ID and requested power information of the wireless power receiving device. As an example, the information request signal may be transmitted in the form of a data packet message. As another example, the information request signal may be transmitted in the form of a digital ping according to a predetermined standard between the wireless power transmitting device and the wireless power receiving device. In response to the information request signal, the wireless power receiving device may optionally transmit the ID and configuration information to the wireless power transmitting device (S220). For example, the configuration information may include the requested amount of power or the maximum amount of power provided to the wireless power receiving device. In some implementations, the information request signal and the ID and configuration information may be communicated using out-of-band communication (separate from the wireless power signal), such as NFC or Bluetooth.

[0101] The wireless power transmitting device sets parameters (called operating points) for power transmission based on the ID and configuration information, and performs wireless power transmission to the wireless power receiving device (S230). For example, the wireless power transmitting device may create a power transmission contract based on the ID and configuration information, and control wireless power transmission according to the power transmission contract. A process performed by the wireless power transmitting device from the start to the end of wireless power transmission to the wireless power receiving device may be called a (wireless) power transmission phase. The wireless power receiving device can provide the received wireless power to an external load such as a battery.

[0102] The wireless power transmitting device can monitor parameters for power transmission and can stop wireless power transmission when any one of the parameters exceeds a specified limit. Alternatively, the wireless power transmitting process of S230 may be terminated at the request of the wireless power receiving device. For example, the wireless power receiving device may transmit a signal to the wireless power transmitting device requesting termination of wireless power transmission when the battery is fully charged.

[0103] During the wireless power transmission process of S230, the wireless power receiving device continues to transmit a control error packet (CEP) periodically or non-periodically to the wireless power transmitting device (S240-1, S240-2, and S240-3). This is performed to control the amount of power transmitted from the wireless power transmitting device to the wireless power receiving device, i.e., to perform power control. The power control process such as steps S240-1 to S240-3 may include the power control process according to the embodiment of FIG. 3.

[0104] FIG. 2 also illustrates a case where a control error packet is not received within a predetermined period T (e.g., 1.8 seconds) after a previous control error packet. The expected (but not received) control error packet is shown as S240-4. In response to not receiving the control error packet within the predetermined period T, the wireless power transmitting device may determine that the wireless power receiving device has been removed from the charging area and stop wireless power transmission (S250). The wireless power transmitting device may be requested to stop wireless power transmission when the user removes the wireless power receiving device from the charging area. Furthermore, the wireless power transmitting device may stop wireless power transmission when the wireless power receiving device indicates a battery full charge state.

[0105] Another problem may occur as a result of distortions or out-of-range parameters in control error packets or other feedback parameters. For example, during battery charging, load fluctuations may cause the charging current to change irregularly. Since load modulation is used to communicate the packets, the load fluctuations may distort the packets. If such distortions occur frequently, the wireless power transmitting device may discard the erroneous packets and possibly terminate the transmission of power to the wireless power receiving device. This may cause unnecessary delays in control that may also lead to interruption of wireless power transmission or delay in battery charging.

[0106] 3 shows an example of a power control process 300 executed between the wireless power transmitting device 102 and the wireless power receiving device 118. Referring to FIG. 3, the wireless power receiving device 118 selects a desired control point (S300). Here, the control point may include a current and / or a voltage, a temperature of a part of the wireless power receiving device, etc. The wireless power receiving device 118 determines an actual control point based on the wireless power transmission 380 received by the power receiving unit 305 from the power conversion unit 370 of the wireless power transmitting device 102 (S310).

[0107] The wireless power receiving device 118 calculates a control error value using the desired control point and the actual control point (S320). For example, the wireless power receiving device 118 may calculate the control error value by a (relative) difference between the desired voltage (or current) and the actual voltage (or current). The wireless power receiving device 118 generates control signaling based on the control error value and transmits it to the wireless power transmitting device (S330). In conventional communication techniques, the control signaling 330 may be encoded in a control error packet. As described further in this disclosure, the control signaling 330 may be communicated as a PWM signal.

[0108] The wireless power transmitting device 102 may receive the control signaling 330 and set a new operating point based on the control error value (S360), if necessary. Here, for example, the operating point may be at least one of an amplitude, a frequency, and a duty cycle of an AC voltage applied to the primary coil. To determine the new operating point 360, the wireless power transmitting device 102 may determine a new primary cell current (S340). The new primary cell current may be based on the actual primary cell current (S375) and the control signaling 330. The wireless power transmitting device 102 may determine a control for the new primary cell current (S350) and determine a new operating point that satisfies the new primary cell current (S360).

[0109] The wireless power transmitting device 102 performs wireless power transmission 380 to the wireless power receiving device 118 based on the new operating point (S370). In this case, the wireless power transmitting device may maintain the operating point until it receives new control signaling from the wireless power receiving device.

[0110] The power control process 300 described with reference to Figure 3 may be used with conventional communication techniques or with the PWM communication techniques described in this disclosure. The descriptions of Figures 4, 5, 7, and 8 explain how to communicate the control signaling 330 of Figure 3 using conventional communication techniques. The descriptions of Figures 9-13 include examples of PWM communication techniques for communicating the control signaling 330.

[0111] FIG. 4 illustrates a block diagram 400 conceptually illustrating an exemplary control error packet. The control error value 410 may be an 8-bit value. In some implementations, the control error value 410 may be a two's complement signed integer value ranging from -128 to +127 inclusive. Values ​​outside the indicated range are reserved and are not included in the CEP. Rather, any value outside this range may saturate to the bounds of the range (such as -128 or +127). In some implementations, a positive control error value may cause the wireless power transmitting device to increase the current to its primary coil, and a negative control error value may cause the wireless power transmitting device to decrease the current to its primary coil. Alternatively or additionally, a positive control error value may instruct the wireless power transmitting device to increase its voltage. In some implementations, the voltage may be increased by decreasing the operating frequency of the wireless power signal instead of or in addition to increasing the voltage of the wireless power signal. A negative control error value may instruct the wireless power transmitting device to decrease the voltage. In some implementations, the voltage may be reduced by increasing the operating frequency instead of, or in addition to, reducing the voltage of the wireless power signal.

[0112] The CEP may include a preamble 422, a header 424, a message portion 426, and a checksum 428. The preamble 422 may be a pattern of all 1's bits. The header 424 may include a value indicating the type of packet. The message portion 426 may be populated with a control error value 410 and may be 8 bits. Similarly, the header 424 and checksum 428 may each be 8 bits long. The preamble 422 signals the start of the packet and may be 11-25 bits long. For purposes of this disclosure, a minimum preamble 422 of 11 bits is described.

[0113] Each 8-bit portion of the header 424, the message portion 426, and the checksum 428 may be byte-encoded. The byte-encoding is further described with reference to FIG. 5. As a result of the byte-encoding, each 8-bit portion of the header 424, the message portion 426, and the checksum 428 is encoded with 11 bits. Thus, the total length of the CEP 450 signaled using conventional communication techniques is 44 modulation bits (a minimum of 11 modulation bits for the preamble 432, 11 modulation bits for the header 434, 11 modulation bits for the message portion 436, and 11 modulation bits for the checksum 438). Each modulation bit is modulated according to a communication frequency of 2 kHz such that one modulation bit is communicated every 0.5 ms. Thus, the time to modulate and transmit a full CEP is 22 ms.

[0114] FIG. 5 shows a block diagram 500 that conceptually illustrates byte encoding. Eight data bits 510 are encoded with a start bit 512, a parity bit 514, and a stop bit 516. Thus, the byte encoding bits 520 includes 11 bits per byte. The start bit 512 is 0. The data bits are ordered from the least significant bit (LSB). For communication from a wireless power transmitting device to a wireless power receiving device, the parity is even, which means that if the data byte contains an odd number of 1 bits, the parity bit is set to 1. Otherwise, the parity bit is set to 0. For communication from a wireless power receiving device to a wireless power transmitting device, the parity bit is odd, which means that if the data byte contains an even number of 1 bits, the parity bit is set to 1. Otherwise, the parity bit is set to 0. The stop bit is 1.

[0115] FIG. 6 shows a block diagram conceptually illustrating an exemplary wireless power receiving device 600. The wireless power receiving device 600 may be an example of the wireless power receiving device 118 described with reference to FIGS. 1, 2, and 3. The wireless power receiving device 600 includes a secondary coil 602. The secondary coil 602 may be connected to a rectifier 604 via a series capacitor 626. The rectifier 604 may be electrically coupled to a load 608 or an energy storage device (not shown, such as a battery) via a series switch (not shown). The wireless power receiving device 600 may also include a communication unit 632. In some implementations, the wireless power receiving device 600 may also include a communication interface (not shown) connected to the communication coil (not shown). The communication unit 632 may be controlled by the receiver controller 624.

[0116] The receiver controller 624 can receive various information and determine control error values ​​or other feedback for communication to the wireless power transmitting device via the communication unit 632. In FIG. 6, dotted lines represent control or information lines to distinguish from solid lines representing electrical circuit lines. The control or information lines may include electrical connections with the receiver controller 624 and other components of the wireless power receiving device 600. In some implementations, the receiver controller 624 can receive information indicative of load settings and power estimates from a load controller or battery management system (not shown) connected to the load 608. The receiver controller 624 can also receive first voltage information from a first voltage sensor 618 connected to the secondary coil 602. The first voltage information can indicate a peak voltage of the secondary coil 602. The receiver controller 624 can also receive second voltage information from a second voltage sensor 614 connected to the rectifier 604. The second voltage information can indicate a voltage available to the load 608. The receiver controller 624 can also receive information regarding current from a current sensor 612 connected to the rectifier 604. The information about the current may indicate the amount of current available to the load 608 .

[0117] The receiver controller 624 may transmit a control error value or other information to the wireless power transmitting device based on the first voltage information, the second voltage information, or information on the current, among other examples. In some cases, the receiver controller 624 may determine a control error value based on one or more of the load setting, the power estimate of the load, the first voltage information, the second voltage information, and information on the current as part of a feedback mechanism. In some implementations, the communication unit 632 is configured to use load modulation to communicate with the wireless power transmitting device over a communication channel that includes the secondary coils 602. The communication channel may be used to communicate information regarding the receiver type, power capabilities, number of secondary coils, secondary coil identification information (such as an identifier (ID) tag), load voltage, charge state, and received power from each of the secondary coils, among other examples. In some implementations, ASK modulation may be used on the communication path from the wireless power receiving device 600 to the wireless power transmitting device. The types of modulation described in this application are for illustrative purposes and alternative types of modulation (such as FSK modulation) may be used within the scope of this disclosure. As described herein, the communication unit 632 may also be capable of communicating analog values ​​using pulse width modulation. The receiver controller 624 may control the communication unit 632 using control lines 652 and 654 connected to switches in the communication unit 632. The switches may be set or unset to generate various modulated signals as described herein.

[0118] FIG. 7 shows a signal diagram conceptually illustrating a differential biphase encoding technique 700 for communicating digital signals. Conventional communication techniques based on ASK or FSK can use differential biphase encoding to modulate digital information. The example in FIG. 7 is based on ASK modulation in conventional communication techniques. The differential biphase encoding scheme can be used to modulate data bits onto a wireless power signal. For this purpose, the wireless power receiving device modulates each data bit for a full period t of an internal clock signal 710 (such as from a communication clock) such that the start of the data bit coincides with the rising edge of the clock signal 710. CLK712. The internal clock signal 710 has a frequency f CLK =2 ±4% The wireless power receiving device may have a frequency of 1 kHz. The wireless power receiving device may encode a bit of 1 using two transitions in the wireless power signal, such that the first transition coincides with a rising edge of the clock signal and the second transition coincides with a falling edge of the clock signal. Alternatively, the second transition may occur a period t before the falling edge of the clock signal. CLK The wireless powered device may encode a bit of 0 using a single transition of the wireless power signal that coincides with a rising edge of the clock signal. CLK FIG. 7 also shows an example of one bits 722 and 726 having two transitions between them, each with a respective period t CLK Illustrated are examples of bits 724 and 728 of 0 with only one transition during each period t CLK may be of duration 0.5 ms and may contain either a bit of 1 or a bit of 0 digital information. The diagram of Figure 7 is based on an amplitude modulated signal where load modulation may be used to modify the amplitude of the power signal.

[0119] FIG. 8 illustrates a timing diagram 800 conceptually illustrating a plurality of control error packets. FIG. 8 illustrates an example timing for communicating control error values ​​via a plurality of CEPs 810, 820, and 830. Each CEP may be communicated using the differential bi-phase encoding technique described with reference to FIG. 7. As described with reference to FIG. 5, each CEP 810, 820, and 830 may consist of 44 bits of digital information. Thus, the communication time for communicating each CEP 810, 820, and 830 is 22 ms. Furthermore, the wireless powered device may include a control delay of at least 29 ms between each CEP 810, 820, and 830. Thus, the wireless powered device may communicate three CEPs, each with a single control error value, over approximately 104 ms. The amount of time required to communicate 100 control error values ​​using a CEP is approximately 4 seconds. As further described with reference to FIG. 12 and FIG. 13, this conventional communication technique is very slow compared to the PWM communication technique described in this disclosure.

[0120] FIG. 9 illustrates a signal diagram conceptually illustrating an exemplary pulse width modulation (PWM) communication technique 900. FIG. 9 illustrates a PWM signal 920 that a first device (such as a wireless power transmitter) can detect in a load modulation communication from a second device (such as a wireless power receiver). In some implementations, the wireless power receiver can convert the control error value into a pulse width ratio. The pulse width ratio indicates the percentage of the pulse width (on-time duration) of the pulses in the pulse time slot. In some implementations, the pulse time slot is of the same duration (0.5 ms) that would otherwise be used for a single ASK modulation bit. FIG. 9 illustrates a PWM signal 920 that includes 10 consecutive pulses communicated using load modulation. Each pulse occupies a pulse time slot 915 that coincides with the 0.5 ms period that would otherwise be used for a 2 kHz communication frequency. Thus, in some implementations, the PWM communication technique can use the same internal clock signal 710 (not shown) as described with reference to FIG. 7. However, rather than using a differential bi-phase encoding technique, the PWM signal 920 may use a variable pulse width to communicate an analog value. In the example of FIG. 9, load modulation may be used to modify the amplitude of the power signal according to a desired pulse width. For example, a first load may generate a first amplitude during the on-time duration of the pulse width and a second amplitude during the off-time duration. Alternatively or additionally, a change in frequency as described with reference to FIG. 17 may be used to differentiate between the on-time duration of the pulse width and the remaining off-time during the pulse time slot 915.

[0121] In the example shown in FIG. 9, there are 10 pulses in the PWM signal 920. Each pulse can communicate a control error value. In communicating the PWM signal 920, the wireless power receiving device can convert the control error value to a pulse width (e.g., using the calculations described with reference to FIG. 11A). In receiving the PWM signal 920, the wireless power transmitting device can detect the pulse width and determine the control error value therefrom (e.g., using the calculations described with reference to FIG. 11B). Furthermore, since each pulse represents a control error value, changes in the control error value can be quickly communicated in subsequent pulses. For example, the pulse 925 in the first pulse time slot 915 has a pulse width ratio of 70 percent (%) of the duration of the first pulse time slot 915 (e.g., 0.5 ms). Thus, the pulse 925 can have a pulse width (duration) of 0.35 ms (70 percent of the 0.5 ms duration of the first pulse time slot 915). A pulse width ratio of 70% may correspond to a particular control error value (eg, 51, using the calculations described with reference to FIGS. 11A and 11B).

[0122] As shown at time 930, the control error value may change. For example, instead of a control error value of 51, the wireless powered device may determine a new control error value of 25. After time 930, a subsequent pulse 945 may have a pulse width (duration) of 0.30 ms. The 0.30 ms pulse width represents a pulse width ratio of 60% of the duration of the corresponding pulse time slot 935. The 60% pulse width ratio may correspond to a new control error value (e.g., 25, using the calculations described with reference to FIGS. 11A and 11B).

[0123] FIG. 10 illustrates an exemplary relationship 1110 between control error values ​​and pulse width ratios. A control error value of -128 may correspond to a pulse width ratio of 0% (0.0), and a control error value of 127 may correspond to a pulse width ratio of 100% (1.0). A pulse width ratio of 50% (0.5) may correspond to a control error value of 0. It is apparent that the exemplary translations illustrated in FIG. 10 are provided for educational purposes, and other translations may be possible. For example, negative control error values ​​may be represented in a range of pulse width ratios from 0.5 to 1.0, and positive control error values ​​may be represented in a range of pulse width ratios from 0.0 to 0.5. In any case, there may be a defined transformation that can convert control error values ​​between -128 and 127 to a range of pulse width ratios. For simplicity, the exemplary diagram of FIG. 10 illustrates a range of pulse width ratios from 0.0 to 1.0. In some implementations, a pulse width ratio of 0.0 or 1.0 may be a reserved value such that a range of pulse width ratios ranges between a minimum value (eg, 3%) and a maximum value (eg, 95%).

[0124] 11A shows an exemplary calculation for determining a pulse width representing a control error value. The wireless power receiving device can determine the pulse width ratio based on an equation that converts the control error value to a pulse width ratio. The wireless power receiving device can determine the pulse width (pulse on-time duration) by multiplying the pulse width ratio by the duration of the pulse time slot. For example, a first equation 1110 shows an exemplary calculation (1) that converts the control error value to a pulse width ratio. JPEG0007676093000001.jpg27145(1)

[0125] A second equation 1120 shows an exemplary calculation (2) for converting the pulse width ratio to a pulse width. JPEG0007676093000002.jpg12114(2)

[0126] Therefore, the wireless power receiving device must set the pulse width (t ON The PWM switch or modulator circuit can be controlled so that the PWM signal has a desired pulse width ratio, where PWM signal 1 has a desired pulse width ratio, which represents the control error value.

[0127] FIG. 11B illustrates an exemplary calculation for determining a control error value based on a pulse. The wireless power transmitting device detects a pulse and calculates a control error value based on the pulse time slot t SLOT The on-time duration of the pulse during ON The wireless power transmitting device may convert the pulse width ratio into a control error value. For example, a third equation 1130 shows an exemplary calculation (3) for determining a pulse width ratio based on a detected pulse. JPEG0007676093000003.jpg2883(3)

[0128] A fourth equation 1140 shows an exemplary calculation (4) for converting the pulse width ratio into a control error value. JPEG0007676093000004.jpg11114(4)

[0129] As further explained with reference to Figure 10, the pulse width ratio can be calculated by an offset of the control error value such that negative values ​​of the control error value can be represented by pulses. The exemplary offset (of negative 128) is only one example, and other conversions between control error values ​​and pulse width ratios are possible.

[0130] 12A shows a timing diagram 1200 that conceptually illustrates the signaling of multiple pulses. Each pulse 1210 may have a pulse width ratio that conveys an analog representation of a feedback parameter (such as a control error value). Each pulse is equal to or exceeds a communication clock period t CLK 1.5 ms. Thus, three pulses (each corresponding to a control error value) may be communicated in 1.5 ms. Approximately 100 pulses may be communicated during a 50 ms period. Recall from the discussion of FIG. 8 that conventional communication techniques using modulated CEPs as digital information take approximately 4 seconds to communicate 100 CEPs. Thus, one skilled in the art will readily recognize that the PWM communication techniques described in this disclosure provide a much faster communication technique.

[0131] FIG. 12B shows another timing diagram 1210 conceptually illustrating the signaling of multiple pulses, with a pulse occurring in every other pulse time slot. As shown in FIG. 12B, the pulses may be separated by intermediate pulse periods. Thus, a pulse may occur during an intermediate pulse period 1217 without a pulse after a first pulse period 1215. The intermediate pulse period may be used, for example, to provide time for a change in operating point or a recalculation of a control error value. Using the approach described in FIG. 12B, different control error values ​​may be communicated by pulses of 1 ms each (0.5 ms for pulse time slot 1215 with a pulse and 0.5 ms for intermediate pulse period 1217). The approximate time to communicate 100 control error values ​​is 100 ms.

[0132] FIG. 12C shows another timing diagram 1220 conceptually illustrating the signaling of multiple pulses where the feedback parameter can be encoded into two pulses. The first pulse in the first pulse time slot 1225 may have a pulse width ratio that represents the sign (positive or negative) of the control error value. For example, a pulse width ratio of 25% can represent a negative error value and a pulse width ratio of 75% can represent a positive error value. The second pulse in the second pulse time slot 1227 may have a variable pulse width ratio that represents the magnitude of the control error value (unsigned) encoded as a pulse width ratio between 0 and 1. While this example uses two pulses (hence twice the time) to convey the control error value, such an implementation may reduce the possibility of errors due to coding noise at high power.

[0133] Although FIG. 12C illustrates a control error value conveyed via two pulses, other examples are possible. For example, for other types of feedback parameters, a series of consecutive pulses can indicate different components of the feedback parameter. The components may include a sign and a magnitude, as described in the previous examples. Alternatively or additionally, the components may include different variable values, orders of magnitude, coarse or fine grained adjustments, or indications, among other examples. The series of consecutive pulses may include two pulses, or other amounts of pulses.

[0134] FIG. 13 illustrates a timing diagram 1300 conceptually illustrating signaling for activating or deactivating a PWM communication technique. When the PWM communication technique is activated, the wireless power transmission system may be referred to as using analog control. In some embodiments, the wireless power transmission system may dynamically enable or disable analog control. For example, communication of identification and configuration information may utilize packet-based modulation of digital information. The packet-based modulation may use a differential bi-phase coding technique that is well suited for communication of digital information as bits. In some implementations, the wireless power receiving device and the wireless power transmitting device may exchange capability information indicating whether they are capable of implementing the PWM communication technique described in this disclosure. If both devices support the PWM communication technique, a start analog control packet 1308 may be used to enable the PWM communication technique. For example, after a handshake and configuration process using packet-based modulation of digital information, the wireless power receiving device (or the wireless power transmitting device) may communicate a start analog control packet 1308 to indicate that it is changing to the PWM communication technique. The start analog control packet 1308 may be formatted as a packet, similar to the CEP described with reference to FIG. 4. The start analog control packet 1308 may include a predetermined value in a header or message portion of the packet to indicate a change to the PWM communication technique. For example, the header may include a predetermined value to identify the packet type of the start analog control packet 1308. The wireless powered device can then communicate the control error value (or other information) as a PWM pulse 1210, as described with reference to FIG.

[0135] The End Analog Control Pattern 1317 can signal a change to a packet-based communication technique. The End Analog Control Pattern 1317 can include a pattern of consecutive pulses with a predetermined pulse width or a null signal for a predetermined time (as shown in FIG. 13). The pattern of consecutive pulses can precede the End Analog Control Packet 1318 or other packets (not shown). For example, a series of n consecutive pulses with the same pulse width ratio can inform the wireless power transmitting device to begin detecting the preamble of the End Analog Control Packet 1318. The series of n consecutive pulses may have a reserved pulse width ratio, such as a minimum or maximum value (0.03 or 0.95) or any other predetermined reserved value.

[0136] In some implementations, the end analog control pattern 1317 may be followed by a digital end analog control packet 1318. The end analog control packet 1318 may include a digital packet including a preamble, a header, a message, and a checksum portion. The end analog control packet 1318 may include a predefined value in the header or message portion of the packet to indicate a change to a traditional packet-based communication technique. For example, the header may include a predefined value to identify the packet type of the end analog control packet 1318.

[0137] FIG. 14 illustrates a block diagram conceptually illustrating an example wireless powered device 1400 that can use PWM-based control signaling over an out-of-band communication channel. The components of the wireless powered device 1400 are similar to the similar components described with reference to the wireless powered device 600 of FIG. 6. However, the wireless powered device 1400 further includes a communication interface 1426 and a communication coil 1428. The communication coil 1428 may be a communication antenna. In some implementations, the communication interface 1426 may support short-range communication (NFC) or Bluetooth™ communication, among other example communication protocols. The receiver controller 624 may be configured to transmit data to the communication interface 1426 for communication according to a communication protocol supported by the communication interface 1426. In some implementations, the communication interface 1426 may communicate data using the PWM-based communication techniques described herein.

[0138] FIG. 15 shows a flow diagram illustrating an example operation of a process for using PWM communication techniques in a wireless power transmitting device. The operations of process 1500 may be performed by a wireless power transmitting device described herein. For example, process 1500 may be performed by a wireless power transmitting device 102 described with reference to FIG. 1, FIG. 2, and FIG. 3. In some implementations, the operations of process 1500 may be performed by a wireless power receiving device such as wireless power receiving device 118 described with reference to FIG. 1, FIG. 2, and FIG. 3, wireless power receiving device 600 described with reference to FIG. 6, or wireless power receiving device 1400 described with reference to FIG. 14. In some implementations, the operations of process 1500 may be performed by an apparatus such as apparatus 1900 described with reference to FIG. 19. For simplicity, the operations are described as being performed by an apparatus.

[0139] In block 1510, the device may transmit wireless power to a wireless power receiving device via the at least one primary coil.

[0140] In block 1520, the device may receive a pulse width modulated (PWM) signal from the wireless powered device. The PWM signal may include one or more pulses.

[0141] In block 1530, the device may determine a feedback parameter based on the pulse width of the one or more pulses.

[0142] At block 1540, the device may manage a transfer of wireless power from the wireless power transmitting device to the wireless power receiving device based at least in part on the feedback parameters.

[0143] FIG. 16 shows a flow diagram illustrating an example operation of a process for using PWM communication techniques in a wireless power receiving device. The operations of process 1600 may be performed by a wireless power receiving device described herein. For example, the operations of process 1600 may be performed by a wireless power receiving device such as wireless power receiving device 118 described with reference to FIG. 1, FIG. 2, and FIG. 3, wireless power receiving device 600 described with reference to FIG. 6, or wireless power receiving device 1400 described with reference to FIG. 14. In some implementations, process 1600 may be performed by wireless power transmitting device 102 described with reference to FIG. 1, FIG. 2, and FIG. 3. In some implementations, the operations of process 1500 may be performed by an apparatus such as apparatus 1900 described with reference to FIG. 19. For simplicity, the operations are described as being performed by an apparatus.

[0144] In block 1610, the device may receive wireless power from the wireless power transmitting device via at least one secondary coil of the wireless power receiving device.

[0145] At block 1620, the device may determine feedback parameters based on the wireless power. The feedback parameters may be for the wireless power transmitting device to manage the transmission of wireless power.

[0146] In block 1630, the device may communicate a pulse width modulated (PWM) signal from the wireless power receiving device to the wireless power transmitting device. The PWM signal may include one or more pulses. Each pulse may have a pulse width based at least in part on the feedback parameters.

[0147] FIG. 17 illustrates a signal diagram 1700 conceptually illustrating an example frequency variation based on a PWM communication technique. Some of the examples in this disclosure are described in the context of a load modulated signal that varies the current according to a PWM signal 1710. However, PWM communication techniques can also be used with an amplitude modulated signal 1720 or a frequency modulated signal 1730. For simplicity, FIG. 17 illustrates a PWM signal 1710 having two pulses. Each pulse may have a pulse width with an on-time duration 1712 during a pulse time slot 1711 to distinguish it from the remaining off-time 1714. In a first example, the PWM signal 1710 can be used to vary the amplitude of the communication signal 1720 such that a first amplitude 1722 indicates the on-time of the pulse. A second amplitude 1724 can be used during the off-time. In a second example, the PWM signal 1710 can be used to vary the frequency of the communication signal 1730 such that a first frequency 1732 indicates the on-time of the pulse. A second frequency 1734 may be used during the off times.

[0148] FIG. 18 shows a flow diagram illustrating an example operation of another process using PWM-based control signaling in a wireless power transmitting device. The operations of process 1800 may be performed by a wireless power transmitting device described herein. For example, process 1800 may be performed by a wireless power transmitting device 102 described with reference to FIG. 1, FIG. 2, and FIG. 3. In some implementations, the operations of process 1800 may be performed by a wireless power receiving device such as wireless power receiving device 118 described with reference to FIG. 1, FIG. 2, and FIG. 3, wireless power receiving device 600 described with reference to FIG. 6, or wireless power receiving device 1400 described with reference to FIG. 14. In some implementations, the operations of process 1500 may be performed by an apparatus such as apparatus 1900 described with reference to FIG. 19. For simplicity, the operations are described as being performed by an apparatus.

[0149] Thus far, examples in this disclosure have been based on feedback of control signaling from a wireless power receiving device to a wireless power transmitting device. However, the PWM-based communication techniques in this disclosure can also be used for communication from a wireless power transmitting device to a wireless power receiving device. For example, different pulse widths can be used to indicate analog values, predefined messages, feed-forward information, or other signaling from a wireless power transmitting device to a wireless power receiving device. Examples of information typically communicated from a wireless power transmitting device to a wireless power receiving device may include an acknowledgement (ACK) message value, a non-acknowledgement (NAK) message value, or a not-defined (ND) message value. Each of these signals may be associated with a predefined pulse width (PWM value) that can be modulated with a wireless power signal or an out-of-band communication signal. Other types of message values ​​may be converted to PWM values ​​using a conversion function.

[0150] In block 1810, the device may transmit wireless power to a wireless power receiving device via the at least one primary coil.

[0151] In block 1820, the device may determine a message value for communicating with the wireless powered device.

[0152] In block 1830, the device may determine a pulse width of one or more pulses of a pulse width modulated (PWM) signal based at least in part on the message value.

[0153] In block 1840, the device may transmit a frequency modulated signal from the wireless power transmitting device to the wireless power receiving device based on the pulse width. The frequency modulated signal may have a first frequency during an on-time duration of the pulse width. The frequency modulated signal may have a second frequency during times other than the on-time duration of the pulse width.

[0154] FIG. 19 illustrates a block diagram of an exemplary device for use in a wireless power system. In some implementations, the device 1900 may be a wireless power transmitting device (such as the wireless power transmitting device 102) described herein. In some implementations, the device 1900 may be an example of any of the wireless power transmitting device 102, the wireless power receiving device 118, the wireless power receiving device 600, or the wireless power receiving device 1400 described herein. The device 1900 may include a processor 1902 (possibly including multiple processors, multiple cores, multiple nodes, or multi-threading implementations, etc.). The device 1900 may also include a memory 1906. The memory 1906 may be a system memory or any one or more of the possible implementations of the computer-readable media described herein. The device 1900 may also include a bus 1911 (e.g., PCI, ISA, PCI-Express, HyperTransport®, InfiniBand®, NuBus®, AHB, AXI, etc.).

[0155] The device 1900 may include one or more controllers 1962 configured to manage multiple primary or secondary coils (such as a coil array 1964). In some implementations, the controller 1962 may be distributed within the processor 1902, the memory 1906, and the bus 1911. The controller 1962 may perform some or all of the operations described herein. For example, the controller 1962 may implement the process described with reference to any one of Figures 2, 3, 15, 16, 17, or any combination thereof.

[0156] The memory 1906 may include computer instructions executable by the processor 1902 to perform the functions of the embodiments described with reference to Figures 1-18. Any of these functions may be implemented partially (or entirely) in hardware or in the processor 1902. For example, the functions may be implemented in an application specific integrated circuit, logic implemented in the processor 1902, a co-processor on a peripheral device or card, etc. Furthermore, an implementation may include fewer or additional components not shown in Figure 19. The processor 1902, the memory 1906, and the controller 1962 may be coupled to a bus 1911. Although shown as being coupled to the bus 1911, the memory 1906 may be coupled to the processor 1902.

[0157] 1-19 and the operations described herein are examples intended to aid in understanding exemplary implementations and should not be used to limit potential implementations or to limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some different operations.

[0158] The diagrams, operations, and components described herein are examples intended to aid in understanding exemplary implementations and should not be used to limit potential implementations or to limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some different operations.

[0159] As used herein, phrases referring to a list of items "at least one of" or "one or more of" refer to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover the possibilities of a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0160] The various example components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in connection with the embodiments disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, including the structures disclosed herein and structural equivalents thereof. Interchangeability of hardware, firmware, and software has been generally described in terms of functionality and illustrated in the various example components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.

[0161] The hardware and data processing devices used to implement the various example components, logic, logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed using general purpose single or multi-chip processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices (PLDs), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration. In some implementations, certain processes, operations, and methods may be performed by circuitry specific to a given function.

[0162] As mentioned above, some aspects of the subject matter described herein can be implemented as software. For example, various functions of components disclosed herein, or various blocks or steps of methods, operations, processes, or algorithms disclosed herein, can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor-executable instructions or computer-executable instructions encoded on one or more tangible processor-readable or computer-readable storage media for execution by or control of the operation of a data processing device, including the components of the device described herein. By way of example and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM, or other optical disk storage devices, magnetic disk storage devices, or other magnetic storage devices, or any other medium that can be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

[0163] Various modifications to the embodiments described in this disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the claims are not intended to be limited to the embodiments shown herein, but are to be accorded the widest scope consistent with the present disclosure, the principles, and novel features disclosed herein.

[0164] Moreover, various features described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can be implemented in multiple embodiments separately or in any suitable subcombination. Thus, although features may be described above as acting in a particular combination and initially claimed as such, one or more features from the claimed combination can, in some cases, be deleted from the combination, and the claimed combination can be directed to a subcombination or a variation of the subcombination.

[0165] Similarly, although operations are shown in the figures in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown, or in any sequential order, or that all of the operations shown be performed, to achieve desirable results. Additionally, the figures may generally depict one or more exemplary processes in the form of a flow chart or diagram. However, other operations not shown may be incorporated into the exemplary process depicted in the schematic. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the depicted operations. In some circumstances, multitasking and parallel processing may be advantageous. Additionally, the separation of various system components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. A method performed by a wireless power transmitting device, comprising: Transmitting wireless power to a wireless power receiving device via at least one primary coil; receiving a pulse width modulated (PWM) signal from the wireless power receiving device, the PWM signal including one or more pulses; determining a feedback parameter based on a pulse width of the one or more pulses; and managing the transfer of the wireless power from the wireless power transmitting device to the wireless power receiving device based at least in part on the feedback parameters; receiving the PWM signal includes activating a PWM communication technique for analog control based on the feedback parameter; activating the PWM communication technique; transmitting a first packet indicating that the wireless power transmitting device supports the PWM communication technology to the wireless power receiving device; receiving a second packet from the wireless powered device indicating that the wireless powered device is activating the PWM communication technique; The method further comprises:

2. 2. The method of claim 1 , wherein the feedback parameter is a control error value, and managing the transmission of the wireless power includes setting an operating point for the transmission of the wireless power based at least in part on the control error value.

3. 2. The method of claim 1, wherein the feedback parameter is indicative of a load power, and managing the transmission of the wireless power includes determining whether a foreign object is detected based on a comparison of the load power and the transmitted amount of wireless power.

4. The method of claim 1 , wherein receiving the PWM signal comprises receiving a number of pulses occupying respective pulse time slots.

5. 5. The method of claim 4, wherein the duration of each pulse time slot is 0.5 milliseconds such that said pulse time slot corresponds to a 2 kHz communication clock cycle.

6. The method of claim 4 , wherein the PWM signal includes a pulse in every other pulse time slot.

7. 5. The method of claim 4, wherein the one or more pulses include at least a first pulse and a second pulse, a pulse width of the first pulse indicating a sign of the feedback parameter and a pulse width of the second pulse indicating a magnitude of the feedback parameter.

8. receiving a start analog control packet prior to receiving the PWM signal, the start analog control packet indicating that the PWM signal follows the start analog control packet; The method of claim 1 further comprising:

9. receiving the initiating analog control packet encoded as a differential biphase encoded signal; receiving the PWM signal as one or more pulses having pulse widths corresponding to one or more analog values ​​of the feedback parameter; The method of claim 8 further comprising:

10. receiving a series of consecutive pulses corresponding to a predetermined pattern of pulse widths; determining that the series of consecutive pulses indicates an end of the PWM signal; The method of claim 9 further comprising:

11. receiving a termination analog control packet or other packet encoded as a differential biphase encoded signal after said termination of said PWM signal; The method of claim 10 further comprising:

12. The method of claim 1 , wherein receiving the PWM signal comprises receiving the PWM signal via the primary coil.

13. The method of claim 1 , wherein receiving the PWM signal comprises receiving the PWM signal via a wireless communication interface separate from the primary coil.

14. The method of claim 13 , wherein the wireless communication interface is a short-range radio frequency interface or a short-range wireless communication interface.

15. The method of claim 1 , wherein receiving the PWM signal comprises detecting load variations during the transmission of the wireless power.

16. 1. A method performed by a wireless power receiving device, comprising: receiving wireless power from a wireless power transmitting device via at least one secondary coil of the wireless power receiving device; determining a feedback parameter based on the wireless power, the feedback parameter being for the wireless power transmitting device to manage transmission of the wireless power; and communicating a pulse width modulated (PWM) signal from the wireless power receiving device to the wireless power transmitting device, the PWM signal including one or more pulses, each pulse having a pulse width based at least in part on the feedback parameter; prior to communicating the PWM signal, activating a PWM communication technique for analog control based on the feedback parameter; activating the PWM communication technique; receiving, from the wireless power transmitting device, a first packet indicating that the wireless power transmitting device supports the PWM communication technology; communicating a second packet to the wireless power transmitting device indicating that the wireless power receiving device is activating the PWM communication technique; The method further comprises:

17. 17. The method of claim 16, further comprising receiving wireless power after communicating the PWM signal, wherein an operating point of the wireless power transmitting device is adjusted based on the feedback parameter.

18. The method of claim 16 , wherein the feedback parameter is a control error value based on a comparison of a desired control point and an actual control point.

19. Communicating the PWM signal The method of claim 16 , comprising performing load modulation of the wireless power using a communication unit of the wireless power receiving device, the load modulation being based on the pulse width of each pulse.

20. Communicating the PWM signal 17. The method of claim 16, comprising performing a communication modulation using a communication interface separate from the at least one secondary coil of the wireless power receiving device, the communication modulation causing a received or transmitted communication signal to have the one or more pulses.

21. Transmitting the PWM signal periodically determining new feedback parameters; 17. The method of claim 16, comprising: periodically communicating new pulses to the wireless power transmitting device, each new pulse having a corresponding pulse width based on the new feedback parameters.

22. 17. The method of claim 16, wherein communicating the PWM signal includes communicating a plurality of pulses, each pulse occupying a respective pulse time slot, each pulse time slot having a duration of 0.5 milliseconds such that the pulse time slot corresponds to a 2 kHz communication clock cycle.

23. 23. The method of claim 22, wherein the PWM signal includes a pulse in every other pulse time slot.

24. communicating a start analog control packet prior to communicating the PWM signal, the start analog control packet indicating that the PWM signal follows the start analog control packet. The method of claim 16 further comprising:

25. communicating said initiating analog control packet as a differential biphase encoded signal; 25. The method of claim 24, further comprising:

26. Communicating a series of consecutive pulses corresponding to a predetermined pattern of pulse widths, the series of consecutive pulses indicating an end of the PWM signal.

26. The method of claim 25, further comprising:

27. communicating a termination analog control packet or other packet encoded as a differential biphase encoded signal after said termination of said PWM signal.

27. The method of claim 26, further comprising:

28. The method of claim 16 , wherein communicating the PWM signal comprises communicating the PWM signal through the secondary coil.

29. The method of claim 16 , wherein communicating the PWM signal comprises communicating the PWM signal through a wireless communication interface separate from the secondary coil.

30. 30. The method of claim 29, wherein the wireless communication interface is a short-range radio frequency interface or a short-range wireless communication interface.

31. at least one primary coil configured to transmit wireless power to a wireless power receiving device; a communication unit configured to receive a pulse width modulated (PWM) signal including one or more pulses from the wireless power receiving device; determining a feedback parameter based on a pulse width of the one or more pulses; and managing the transfer of the wireless power from the wireless power transmitting device to the wireless power receiving device based at least in part on the feedback parameters. A control unit configured as above, Equipped with receiving the PWM signal includes activating a PWM communication technique for analog control based on the feedback parameter; activating the PWM communication technique; a first packet indicating that the wireless power transmitting device supports the PWM communication technique is transmitted from the communication unit to the wireless power receiving device; The wireless power transmitting device is configured to receive a second packet from the wireless power receiving device indicating that the wireless power receiving device is activating the PWM communication technique.

32. 32. The wireless power transmitting device of claim 31, wherein the feedback parameter is a control error value, and the controller is configured to set an operating point for the transmission of the wireless power based at least in part on the control error value.

33. 32. The wireless power transmitting device of claim 31, wherein the feedback parameter indicates a load power, and the control unit is configured to determine whether a foreign object has been detected based on a comparison between the load power and the transmitted amount of wireless power.

34. The wireless power transmitting device of claim 31 , wherein the communication unit is configured to receive a plurality of pulses occupying respective pulse time slots.

35. 35. The wireless power transmitting device of claim 34, wherein the duration of each pulse time slot is 0.5 milliseconds such that the pulse time slot corresponds to a 2 kHz communication clock cycle.

36. 35. The wireless power transmitting device of claim 34, wherein the PWM signal includes a pulse in every other pulse time slot.

37. 35. The wireless power transmitting device of claim 34, wherein the one or more pulses include at least a first pulse and a second pulse, a pulse width of the first pulse indicating a sign of the feedback parameter and a pulse width of the second pulse indicating a magnitude of the feedback parameter.

38. The communication unit, 32. The wireless power transmitting device of claim 31, configured to receive a start analog control packet prior to receiving the PWM signal, the start analog control packet indicating that the PWM signal follows the start analog control packet.

39. The communication unit, receiving the initiating analog control packet encoded as a differential biphase encoded signal; 40. The wireless power transmitting device of claim 38, configured to receive the PWM signal as the one or more pulses having pulse widths corresponding to one or more analog values ​​of the feedback parameter.

40. the communication unit is configured to receive a series of consecutive pulses corresponding to a predetermined pattern of pulse widths; the controller is configured to determine that the series of consecutive pulses indicates an end of the PWM signal. The wireless power transmitting device according to claim 39.

41. The communication unit, 41. The wireless power transmitting device of claim 40 configured to receive a termination analog control packet or other packet encoded as a differential biphase encoded signal after the termination of the PWM signal.

42. The wireless power transmitting device according to claim 31 , wherein the communication unit is configured to receive the PWM signal via the primary coil.

43. a wireless communication interface separate from the primary coil and configured to receive the PWM signal; The wireless power transmitting device of claim 31 , further comprising:

44. The wireless power transmitting device of claim 43 , wherein the wireless communication interface is a short-range radio frequency interface or a short-range wireless communication interface.

45. at least one secondary coil configured to receive wireless power from a wireless power transmitting device; a control unit configured to determine a feedback parameter based on the wireless power, the feedback parameter being for the wireless power transmitting device to manage transmission of the wireless power; and a communication unit configured to communicate a pulse width modulated (PWM) signal from a wireless power receiving device to the wireless power transmitting device, the PWM signal including one or more pulses, each pulse having a pulse width based at least in part on the feedback parameter; Equipped with and prior to communicating the PWM signal, activating a PWM communication technique for analog control based on the feedback parameter; activating the PWM communication technique includes: the communication unit receives, from the wireless power transmitting device, a first packet indicating that the wireless power transmitting device supports the PWM communication technology; The wireless power receiving device is configured to communicate a second packet to the wireless power transmitting device indicating that the wireless power receiving device is activating the PWM communication technique.

46. the at least one secondary coil is further configured to receive wireless power after the communication unit communicates the PWM signal; an operating point of the wireless power transmitting device is adjusted based on the feedback parameters; 46. ​​The wireless power receiving device according to claim 45.

47. 46. ​​The wireless power receiving device of claim 45, wherein the feedback parameter is a control error value based on a comparison of a desired control point and an actual control point.

48. The communication unit, 46. ​​The wireless power receiving device of claim 45, configured to perform load modulation of the wireless power based on the pulse width of each pulse.

49. and a communication interface separate from the at least one secondary coil of the wireless power receiving device, the communication unit being configured to perform a communication modulation to cause a received communication signal or a transmitted communication signal to have the one or more pulses.

46. ​​The wireless power receiving device according to claim 45.

50. 46. ​​The wireless power receiving device of claim 45, wherein communicating the PWM signal includes communicating a plurality of pulses, each pulse occupying a respective pulse time slot, each pulse time slot having a duration of 0.5 milliseconds such that the pulse time slot corresponds to a 2 kHz communication clock cycle.

51. 51. The wireless power receiving device of claim 50, wherein the PWM signal includes a pulse in every other pulse time slot.

52. The communication unit, 46. ​​The wireless power receiving device of claim 45, configured to communicate a start analog control packet prior to communicating the PWM signal, the start analog control packet indicating that the PWM signal follows the start analog control packet.

53. 53. The wireless power receiving device of claim 52, wherein the communication unit is configured to communicate the initiating analog control packet as a differential biphase encoded signal.

54. The communication unit, 54. The wireless power receiving device of claim 53 configured to communicate a series of consecutive pulses corresponding to a predetermined pattern of pulse widths, said series of consecutive pulses indicating an end of said PWM signal.

55. The communication unit, 55. The wireless power receiving device of claim 54 configured to communicate a terminated analog control packet or other packet encoded as a differential biphase encoded signal after the termination of the PWM signal.

56. The wireless power receiving device of claim 45 , wherein the communication unit is configured to communicate the PWM signal via the secondary coil.

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