Power reception device, power transmission device, method performed by power reception device, method performed by power transmission device, and program

Abstract

A power reception device according to one embodiment of the present disclosure wirelessly receives power from a power transmission device, temporarily stops power reception from the power transmission device, and, when the power reception from the power transmission device is temporarily stopped, transmits a packet for ending the temporary stop to the power transmission device in response to satisfaction of a condition related to resumption of the power reception. A first condition is at least one of a condition that a near field communicationan (NFC) tag is not detected by NFC scanning executed by the power reception device, a condition that a temperature of the power reception device falls below a predetermined value, and a condition that a state-of-charge of a battery of the power reception device is equal to or lower than a predetermined value.

Description

Power receiving equipment, power transmitting equipment, methods performed by power receiving equipment, methods performed by power transmitting equipment, and programs

[0001] This disclosure relates to power receiving equipment, power transmitting equipment, methods performed by power receiving equipment, methods performed by power transmitting equipment, and programs.

[0002] Japanese Patent Publication No. 2023-112407 discloses a power receiving device that transmits information to a power transmitting device regarding the time during which the power transmitting device temporarily suspends power transmission, thereby enabling the power transmitting device to properly perform foreign object detection during the period when power transmission is temporarily suspended.

[0003] Japanese Patent Publication No. 2023-112407

[0004] In order for a power transmission or receiving device to perform a predetermined process, the power transmission device may temporarily suspend power transmission. In this case, if the start and / or end of the predetermined process and the temporary suspension and / or resumption of power transmission and reception are not synchronized, it may become impossible to properly perform the predetermined process, power transmission and reception, or any other processes related to the temporary suspension of power transmission and reception.

[0005] One aspect of the present disclosure aims, in view of the above, to provide a technology for appropriately performing power transmission and reception processing. A power receiving device according to one aspect of the present disclosure includes a power receiving means for receiving power wirelessly from a power transmitting device, and a transmitting means for transmitting a first packet to the power transmitting device to terminate the temporary suspension when the power receiving means has temporarily suspended power reception from the power transmitting device, in response to the fulfillment of a first condition for resuming power reception, wherein the first condition is at least one of the following: no NFC (Near Field Communication) tag is detected by an NFC scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

[0006] According to one aspect of this disclosure, the process of transmitting and receiving power can be appropriately executed.

[0007] This figure shows an example configuration of a wireless charging system according to the first embodiment. This is a functional block diagram showing an example configuration of a power transmission device according to the first embodiment. This is a functional block diagram showing an example configuration of a power receiving device according to the first embodiment. This is a block diagram showing an example of the functional configuration of the control unit of the power transmission device according to the first embodiment. This is a flowchart showing an example of processing of a power transmission device. This is a flowchart showing an example of processing of a power receiving device. This is a sequence diagram showing an example of processing of a power transmission device and a power receiving device according to the first embodiment. This is a flowchart showing an example of processing of a power transmission device according to the first embodiment. This is a flowchart showing an example of processing of a power receiving device according to the first embodiment. This is an explanatory diagram illustrating an example of processing of a packet according to the first embodiment. This is an explanatory diagram illustrating an example of processing of a packet according to the first embodiment. This is a flowchart showing an example of processing of a power transmission device according to the second embodiment. This is a flowchart showing an example of processing of processing of a power receiving device according to the second embodiment. This is an explanatory diagram illustrating an example of processing This is a sequence diagram showing an example of processing for a power transmission and receiving device according to the second embodiment. This is a sequence diagram showing an example of processing for a power transmission and receiving device according to the third embodiment. This is a sequence diagram showing an example of processing for a power transmission and receiving device according to the fourth embodiment. This is a sequence diagram showing an example of processing for a power transmission and receiving device according to the fifth embodiment. This is an explanatory diagram illustrating an example of processing for Cloak according to the first embodiment. This is an explanatory diagram illustrating an example of processing for Cloak according to the first embodiment. This is an explanatory diagram illustrating an example of processing for Cloak according to the first embodiment. This is a diagram illustrating an example of a method for measuring the coupling state index between a power transmission device and a power receiving device according to the sixth embodiment.This is an explanatory diagram of the threshold setting method in state detection by the coupled state index measurement method according to the sixth embodiment. This is a flowchart showing an example of processing of a power transmission device according to the sixth embodiment. This is a flowchart showing an example of processing of a power receiving device according to the sixth embodiment. This is a sequence diagram showing an example of processing of a power transmission device and a power receiving device according to the sixth embodiment.

[0008] The embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Although the embodiments describe several features, not all of these features are essential to this disclosure, and the features may be combined in any way. Furthermore, in the accompanying drawings, the same or similar configurations will be given the same reference numeral. Each embodiment shows a wireless charging system to which a wireless power transmission system is applied. As an example, wireless power transmission based on a standard developed by the Wireless Power Consortium (WPC) (hereinafter referred to as the WPC standard) will be described. An example of a WPC standard is the Qi standard.

[0009] <First Embodiment> [System Configuration] This embodiment will be described with reference to the drawings. Figure 1 is a diagram showing an example of the configuration of a wireless charging system according to this embodiment. This wireless charging system comprises a power transmission device 100, a power receiving device 200, and a charging stand 300.

[0010] In the following, for the sake of brevity, the power receiving device 200 may be referred to as RX200 and the power transmitting device 100 as TX100. The detailed configurations of TX100 and RX200 will be described later using Figures 2 and 3.

[0011] The RX200 is an electronic device that receives power wirelessly from the TX100 and charges its internal battery while placed on the charging base 300. The TX100 is an electronic device that wirelessly transmits power to the RX200 while it is placed on the charging base 300. The charging base 300 is the flat surface of the TX100 closest to the power transmission antenna (power transmission coil) 105, which will be described later, and is also called the Interface Surface. Since the charging base 300 constitutes part of the TX100, in the following, when the RX200 is "placed on the charging base 300", it may be referred to as "placed on the TX100". The spatial range in which the RX200 can receive power from the TX100 is schematically shown in Figure 1 by the dotted line frame 400. The RX200 and TX100 may have functions to perform applications other than wireless charging. For example, RX200 is a smartphone, and TX100 is an accessory device for charging the RX200's battery. However, this disclosure is not limited to this example.

[0012] [Configuration of Power Transmission and Receiving Devices] Next, an example of the configuration of the power transmission device 100 will be described with reference to Figure 2. Figure 2 is a functional block diagram showing an example of the configuration of the power transmission device 100. TX100 includes a control unit 101, a power supply unit 102, a power transmission unit 103, a first communication unit 104, a power transmission antenna (power transmission coil) 105, a memory 106, a resonant capacitor 107, a switch unit 108, a second communication unit 109, and a user interface unit 110. Hereinafter, the user interface will be referred to as UI. In Figure 2, each functional block element is shown as a separate unit, but any multiple functional block elements may be implemented as the same hardware module (for example, on the same chip).

[0013] The control unit 101 controls the entire TX100 by executing a control program stored in the memory 106. The control unit 101 also performs power transmission control, including communication for device authentication in the TX100. Furthermore, the control unit 101 controls the NFC (Near Field Communication) communication function of the second communication unit 109 (described later) and performs NFC scanning to detect NFC tags. In addition, the control unit 101 can perform control for executing applications other than wireless power transmission. The control unit 101 is configured to include one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Alternatively, the control unit 101 may be configured as hardware such as an Application Specific Integrated Circuit (ASIC). Furthermore, the control unit 101 may be configured to include an array circuit such as an FPGA (Field Programmable Gate Array) compiled to perform predetermined processing. The control unit 101 can perform processing to store information that should be stored during the execution of various processes in the memory 106, and can also perform timing processing using a timer (not shown).

[0014] The power supply unit 102 supplies power to each functional block element. The power supply unit 102 includes, for example, a power connection circuit to the commercial power supply and a battery. The battery is charged by the power supplied from the commercial power supply.

[0015] The power transmission unit 103 converts the DC power or AC power input from the power supply unit 102 into AC power in the frequency band used for wireless power transmission, and inputs the converted AC power to the power transmission antenna 105 to generate electromagnetic waves for the RX200 to receive power. For example, the power transmission unit 103 is equipped with an inverter and converts the DC voltage supplied by the power supply unit 102 into an AC voltage using a switching circuit in a half-bridge or full-bridge configuration. The power transmission unit 103 includes a plurality of FETs (Field Effect Transistors) that constitute a bridge, and a gate driver that controls the ON / OFF state of the plurality of FETs.

[0016] The power transmission unit 103 controls the intensity of the electromagnetic waves (transmitted power) output by adjusting the voltage (transmission voltage) or current (transmission current), or both, input to the power transmission antenna 105. The strength of the electromagnetic waves (strength of the transmitted power) is controlled by the magnitude of the transmission voltage or transmission current.

[0017] Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves it outputs (power transmission) by adjusting the voltage, current, or both input to the inverter it has. The voltage input to this inverter will be referred to as the inverter input voltage below. The current input to this inverter will be referred to as the inverter input current below. The strength of the electromagnetic waves (strength of the power transmission) is controlled by the magnitude of the inverter input voltage or inverter input current.

[0018] Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves (transmitted power) to be output by adjusting the voltage, current, or both output from the inverter of the power transmission unit 103. The voltage output from this inverter will be referred to as the inverter output voltage below.

[0019] Furthermore, the current output from this inverter will be referred to as the inverter output current below. The strength of the electromagnetic waves (the strength of the transmitted power) is controlled by the magnitude of the inverter output voltage or inverter output current.

[0020] The power transmission unit 103 controls the output power of AC frequency electromagnetic waves so that it can start or stop power transmission by the power transmission antenna 105 or control the intensity of the electromagnetic waves to be output, based on instruction signals from the control unit 101. The power transmission unit 103 is also assumed to have the power supply capacity to output / supply 15 watts (W) of power to the charging section of the power receiving device 200 which complies with the WPC standard.

[0021] The first communication unit 104 is connected to the control unit 101 and the power transmission unit 103, and communicates with the RX200 for power transmission control based on the WPC standard. The first communication unit 104 performs frequency shift modulation on the electromagnetic wave output from the power transmission antenna 105, transmits information to the RX200, and communicates. Also, the first communication unit 104 demodulates the electromagnetic wave transmitted from the power transmission antenna 105 modulated by the RX200, and acquires the information transmitted by the RX200. The communication by the first communication unit 104 is performed by superimposing a communication signal on the electromagnetic wave transmitted from the power transmission antenna 105. The first communication unit 104 performs so-called in-band communication.

[0022] In addition to the control program, the memory 106 can store information regarding the states of the TX100 and the RX200. Information regarding the states of the TX100 and the RX200 includes a power transmission power value, a power reception power value, and the like. Information regarding the state of the TX100 is acquired by the control unit 101. Information regarding the state of the RX200 is acquired by the control unit of the RX200 and can be received by the first communication unit 104 or the second communication unit 109 described later.

[0023] The switch unit 108 is connected in parallel to the series circuit of the resonance capacitor 107 and the power transmission antenna 105. The control unit 101 transmits a control signal to the switch unit 108 to perform ON / OFF control of the switch unit 108. The power transmission antenna 105 is connected to the resonance capacitor 107. When the switch unit 108 is turned ON and short-circuited by the control signal from the control unit 101, the power transmission antenna 105 and the resonance capacitor 107 form a series resonance circuit and resonate at a specific frequency fA. At this time, a current flows through the closed circuit formed by the power transmission antenna 105, the resonance capacitor 107, and the switch unit 108. On the other hand, when the switch unit 108 is turned OFF by the control signal from the control unit 101 and the circuit is opened, power is supplied from the power transmission unit 103 to the power transmission antenna 105 and the resonance capacitor 107.

[0024] The second communication unit 109 is connected to the control unit 101 and communicates with the RX200 according to a standard different from the WPC standard. For example, the second communication unit 109 communicates with the RX200 using an antenna (not shown) different from the power transmission antenna 105. Examples of the communication method used by the second communication unit 109 include wireless LAN (Local Area Network), Bluetooth (registered trademark) Low Energy (BLE), NFC, and the like. BLE may be a communication method corresponding to a version of the Bluetooth standard version 4.0 or later. The frequency band used for power transmission from the power transmission antenna 105 is different from the frequency band used by the second communication unit 109 for communication. The second communication unit 109 performs so-called out-of-band communication.

[0025] Regarding the communication between the TX100 and the RX200, the TX100 may selectively use any one of a plurality of communication standards to communicate with the RX200. For example, the following communication forms using a plurality of communications shown below are possible. - Communication based on the first standard (WPC standard) performed between the first communication unit 104 of the TX100 and the first communication unit 204 (see FIG. 3) of the RX200. - Communication based on the second standard (a standard other than the WPC standard) performed between the second communication unit 109 of the TX100 and the second communication unit 212 (see FIG. 3) of the RX200.

[0026] The UI unit 110 is connected to the control unit 101 and performs various outputs to the user. The various outputs include operations such as screen display, blinking or color change of an LED (Light Emitting Diode), voice output by a speaker, and vibration of the TX100 main body. The UI unit 110 is realized by a liquid crystal panel, a speaker, a vibration motor, and the like.

[0027] Next, an example of the configuration of the power receiving device 200 will be described with reference to Figure 3. Figure 3 is a block diagram showing an example of the configuration of the power receiving device 200. RX200 includes a control unit 201, a UI unit 202, a power receiving unit 203, a first communication unit 204, a power receiving antenna 205, a charging unit 206, a battery 207, and a memory 208. RX200 further includes a first switch unit 209, a second switch unit 210, a resonant capacitor 211, a second communication unit 212, and a third switch unit 213. In this embodiment, an example is shown where the functional block elements in Figure 3 are individual elements, but multiple functional block elements may be implemented as a single hardware module (for example, within the same chip).

[0028] The control unit 201 controls each functional block element of the RX200 by executing a control program stored in the memory 208. The control unit 201 also controls the NFC communication function of the second communication unit 212 (described later) and performs an NFC scan to detect NFC tags. Furthermore, the control unit 201 can perform control for executing applications other than wireless power transmission. The control unit 201 is configured to include one or more processors such as a CPU or MPU. It can also control the entire RX200 (e.g., the entire smartphone) in cooperation with the OS (Operating System) it is running. Alternatively, the control unit 201 may be composed of hardware such as an ASIC, or it may include an array circuit such as an FPGA compiled to execute predetermined processing. The control unit 201 stores information to be stored during the execution of various processes in the memory 208, and can also execute timing processing using a timer (not shown).

[0029] The UI unit 202 is connected to the control unit 201 and provides various outputs to the user. These outputs include screen displays, LED blinking and color changes, audio output from the speaker, and vibrations of the RX200 unit. The UI unit 202 is implemented using an LCD panel, speaker, vibration motor, etc.

[0030] The power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction based on electromagnetic waves radiated from the TX100's transmitting antenna 105 via the power receiving antenna (power receiving coil) 205. The power receiving unit 203 then converts the AC power into DC power or AC power of a predetermined frequency and supplies power to the charging unit 206. The charging unit 206 charges the battery 207. The power receiving unit 203 includes a rectifier unit (rectifier, rectifier circuit) and a voltage control unit necessary for supplying power to the load in the RX200. The rectifier unit converts the AC voltage and AC current from the transmitting antenna, received via the power receiving antenna 205, into DC voltage and DC current. This DC voltage will be referred to as the rectifier unit output voltage below. This DC current will be referred to as the rectifier unit output current below. The voltage control unit converts the level of the DC voltage (rectifier unit output voltage) output by the rectifier unit to a predetermined level. The predetermined level is the DC voltage level at which the control unit 201 and the charging unit 206 can operate. The power receiving unit 203 supplies power for charging the battery 207 from the charging unit 206. The power receiving unit 203 is assumed to have the power supply capacity to output 15 watts (W) of power to the charging unit 206.

[0031] The first communication unit 204 communicates with the first communication unit 104 of the TX 100 for power receiving control based on the WPC standard. The first communication unit 204 is connected to the power receiving antenna 205 and the control unit 201. The first communication unit 204 demodulates the electromagnetic waves input from the power receiving antenna 205 and acquires information transmitted from the TX 100. The first communication unit 204 performs load modulation, amplitude modulation, or backscatter modulation on the input electromagnetic waves and superimposes a signal related to the information to be transmitted to the TX 100 onto the electromagnetic waves, thereby communicating with the TX 100.

[0032] Memory 208 stores information regarding the status of TX100 and RX200, in addition to the control program. Information regarding the status of RX200 is acquired by the control unit 201. Information regarding the status of TX100 is acquired by the control unit 101 of TX100 and can be received by the first communication unit 204 or the second communication unit 212, which will be described later.

[0033] The second communication unit 212 is connected to the control unit 201 and communicates with the TX100 using a standard different from the WPC standard. For example, the second communication unit 212 communicates with the TX100 using an antenna different from the receiving antenna 205. Examples of communication methods used by the second communication unit 212 include wireless LAN, BLE, NFC, etc. BLE can be any communication method compatible with Bluetooth standard version 4.0 or later. The frequency band used when receiving power with the receiving antenna 205 is different from the frequency band used by the second communication unit 212 for communication.

[0034] Regarding communication between TX100 and RX200, RX200 may selectively use one of several communication standards to communicate with TX100. For example, the following communication configurations using multiple communication standards selectively are possible: • Communication based on a first standard (WPC standard) between the first communication unit 104 of TX100 and the first communication unit 204 of RX200. • Communication based on a second standard (a standard other than the WPC standard) between the second communication unit 109 of TX100 and the second communication unit 212 of RX200.

[0035] The first switch unit 209 is located between the charging unit 206 and the battery 207 and is controlled by the control unit 201. The first switch unit 209 has the function of controlling whether or not to supply the power received by the power receiving unit 203 to the battery 207, and the function of controlling the magnitude of the load. When the first switch unit 209 is turned OFF and opened by the control unit 201, the power received by the power receiving unit 203 is not supplied to the battery 207. When the first switch unit 209 is turned ON and short-circuited by the control unit 201, the power received by the power receiving unit 203 is supplied to the battery 207.

[0036] In Figure 3, the first switch unit 209 is located between the charging unit 206 and the battery 207, but the first switch unit 209 may also be located between the power receiving unit 203 and the charging unit 206.

[0037] Alternatively, the first switch unit 209 may be positioned between the closed circuit formed by the receiving antenna 205, the resonant capacitor 211, and the second switch unit 210, and the receiving unit 203. In this case, the first switch unit 209 has the function of controlling whether or not to supply the power received by the receiving antenna 205 to the receiving unit 203.

[0038] Furthermore, although the first switch unit 209 is described as a single functional block element in the example of Figure 3, it is possible to realize the first switch unit 209 as part of the charging unit 206 or the power receiving unit 203. Moreover, this disclosure is not limited to a configuration in which the first switch unit 209 is inserted in series between the charging unit 206 and the battery 207; the first switch unit 209 may also be inserted in parallel between the charging unit 206 and the battery 207. In this case, when the first switch unit 209 is turned OFF and opened by the control unit 201, the power received by the power receiving unit 203 is supplied to the battery 207. When the first switch unit 209 is turned ON and short-circuited by the control unit 201, the power received by the power receiving unit 203 is not supplied to the battery 207.

[0039] On the input side of the power receiving unit 203, the second switch unit 210 is connected in parallel with the resonant capacitor 211. The resonant capacitor 211 is connected to the power receiving antenna 205 via the third switch unit 213. The second switch unit 210 and the third switch unit 213 are controlled by the control unit 201. The third switch unit 213 has the function of controlling whether or not to open the terminals of the power receiving antenna 205. When the control unit 201 turns the third switch unit 213 OFF, the terminals of the power receiving antenna 205 are open. When the control unit 201 turns the third switch unit 213 ON, the power receiving antenna 205 is connected to the power receiving unit 203 via the resonant capacitor 211.

[0040] When the control unit 201 turns on the third switch unit 213 and the second switch unit 210, causing a short circuit, the receiving antenna 205 and the resonant capacitor 211 form a series resonant circuit and resonate at a specific frequency fB. At this time, current flows through the closed circuit formed by the receiving antenna 205, the resonant capacitor 211, and the second switch unit 210, but no current flows to the receiving unit 203. On the other hand, when the second switch unit 210 is turned off and the circuit is opened, the power received by the receiving antenna 205 and the resonant capacitor 211 is supplied to the receiving unit 203. Note that this disclosure is not limited to the example in Figure 3, and the second switch unit 210 may be placed between the receiving antenna 205 and the resonant capacitor 211. When the third switch unit 213 is ON and the second switch unit 210 is ON, the terminals of the receiving antenna 205 are short-circuited. Furthermore, the third switch unit 213 may be positioned between the resonant capacitor 211 and the power receiving unit 203.

[0041] In this wireless charging system, TX100 and RX200 transmit wireless power between the transmitting antenna 105 and the receiving antenna 205 in accordance with the WPC standard. In the WPC standard, the level of load power agreed upon between RX200 and TX100 is defined by a value called Guaranteed Load Power (hereinafter referred to as "GP"). Load power is the power consumed by the load. For example, GP is the power value at which the output of RX200 to the load is guaranteed even if the coupling between the receiving antenna 205 and the transmitting antenna 105 weakens and the power transmission efficiency decreases due to a change in the relative positions of RX200 and TX100. In this specification, the coupling state between the transmitting antenna (transmitting coil) 105 and the receiving antenna (receiving coil) 205 may also be referred to as the coupling state between TX100 and RX200. The load of the RX200 is the charging unit 206, the battery 207, etc., and the value of GP corresponds to the power that is guaranteed to be output from the power receiving unit 203. Alternatively, the value of GP corresponds to the power that is guaranteed to be output from the rectifier unit of the power receiving unit 203. For example, let's assume that the value of GP is 5 (watts) and the positional relationship between the power receiving antenna 205 and the power transmitting antenna 105 changes. In this case, even if the power transmission efficiency decreases, the TX100 will perform power transmission control so that it can output 5 watts to the load of the RX200. Furthermore, GP is determined by negotiations between the TX100 and the RX200. Note that this disclosure is not limited to GP, and this embodiment can be applied to a configuration in which power transmission and reception are performed with power determined by negotiations between the TX100 and the RX200.

[0042] Furthermore, when transmitting power from TX100 to RX200, we consider the case where an object is present near TX100. In this case, the object is one that may affect the power transmission from TX100 to RX200 and is a different object (foreign object) from RX200. Electromagnetic waves for power transmission may affect the foreign object, potentially causing a temperature rise or destruction of the foreign object. In this disclosure, a foreign object is an object that is neither a part of the power receiving device and the product into which the power receiving device is incorporated, nor a part of the power transmitting device and the product into which the power transmitting device is incorporated, but which may generate heat when exposed to a power signal. Examples of foreign objects include paper clips and IC cards. Objects that are essential parts of the power receiving device and the product into which the power receiving device is incorporated, or the power transmitting device and the product into which the power transmitting device is incorporated, but which may unintentionally generate heat when exposed to the radio power transmitted by the power transmitting antenna, are not considered foreign objects.

[0043] The WPC standard specifies a method to suppress the temperature rise and damage of foreign objects by stopping power transmission when foreign objects are present. Specifically, the power transmission device 100 can detect the presence of foreign objects on the charging base 300. The Power Loss method is a method of detecting foreign objects by the difference between the power transmitted by TX100 and the power received by RX200. Alternatively, the Q-value measurement method is a method of detecting foreign objects by the change in the Quality Factor (also called Q-factor, quality coefficient, Q value, etc.) of the power transmission antenna 105 (power transmission coil) in TX100. Or, the Q-value measurement method is a method of detecting foreign objects by the change in the Quality Factor of the resonant circuit including the power transmission antenna 105 and the resonant capacitor 107 in TX100. In this disclosure, the Quality Factor of the power transmission antenna 105 and the Quality Factor of the resonant circuit including the power transmission antenna 105 and the resonant capacitor 107 are referred to as the Quality Factor relating to the power transmission antenna 105. However, the foreign objects detected by TX100 are not limited to objects present on the charging base 300. TX100 can detect foreign objects located in the vicinity of TX100. For example, TX100 can detect foreign objects located within the range of power transmission.

[0044] In this embodiment, RX200 and TX100 communicate for power transmission and reception control based on the WPC standard. The WPC standard defines multiple phases, including the Power Transfer phase in which power transmission is performed and one or more phases prior to actual power transmission. Communication for necessary power transmission and reception control is performed in each phase. For example, foreign object detection using the Power Loss method is performed in the Power Transfer phase based on data obtained in the Calibration phase. Foreign object detection using the Q-value measurement method is performed before power transmission (before Digital Ping transmission and in the Negotiation phase or Renegotiation phase).

[0045] The WPC standard includes the Selection phase, Ping phase, and Configuration phase before power transmission. In addition, there are the Negotiation phase and Calibration phase. The processing of each phase will be explained below. In this embodiment, an example using MPP (Magnetic Power Profile) as the power profile is shown. MPP is adopted in the "Qi2" standard of the wireless power receiving standard "Qi". In the WPC standard, there are BPP (Baseline Power Profile) which transmits 5 watts or less of power to the RX200, EPP (Extended Power Profile) which transmits 15 watts or less of power, and the aforementioned MPP. Here, a power profile is a set of features that defines the compliance level of a power transmitting or receiving device. MPP has the function of precisely fixing the TX100 and RX200 in predetermined positions. Multiple means can be considered for precisely fixing the TX100 and RX200 in predetermined positions. For example, the transmitting antenna (transmitting coil) of the TX100 and the receiving antenna (receiving coil) of the RX200 can be precisely opposed (facing each other) by using the magnets built into the TX100 and RX200, respectively. In other words, in this case, MPP can be said to be an extended function of BPP, a profile (power profile) that uses magnets to align the power transmitting and receiving devices. The magnets may be permanent magnets or electromagnets. Note that BPP and EPP use the 100 kHz band, while MPP uses a frequency of 360 kHz.

[0046] During the Selection phase, the TX100 intermittently transmits Analog Pings to detect when an object is placed on the charging base of the TX100. Analog Ping is a short-duration power signal applied to detect the presence of an object. However, this power signal does not activate the control unit of the power receiving device. For example, it detects when an RX200 or a conductive piece is placed on the charging base. The TX100 detects either or both the voltage and / or current values ​​of the transmitting antenna 105 when the Analog Ping is transmitted. If the voltage value falls below a threshold or the current value exceeds a threshold, the TX100 determines that an object is present and transitions to the Ping phase. Alternatively, TX100 determines that an object exists and transitions to the Ping phase if the Quality Factor obtained from the voltage value satisfies predetermined conditions, or if the Quality Factor obtained from the current value satisfies predetermined conditions.

[0047] In the Ping phase, TX100 transmits a Digital Ping with higher power than Analog Ping. The Digital Ping is a power signal to activate the control unit of RX200, which is mounted on top of TX100. RX200 transmits a Signal Strength (SIG) data packet containing the received voltage value to TX100. In this way, TX100 recognizes that the object detected in the Selection phase is RX200 by receiving a response from RX200 that has received the Digital Ping. Upon receiving notification of the received voltage value from RX200, TX100 transitions to the Configuration phase. Furthermore, before transmitting Digital Ping, TX100 measures the Quality Factor related to the power transmission antenna 105, for example, using Analog Ping. This measurement result is used when performing foreign object detection processing using the Q-value measurement method. Note that, depending on the version of the WPC standard, the Selection phase described above may be included as part of the Ping phase and referred to as the Ping phase.

[0048] During the Configuration phase, TX100 identifies RX200 and obtains equipment configuration information (capability information) from RX200. RX200 transmits signals for the ID data packet and the Configuration data packet.

[0049] The ID data package contains identifier information for RX200, and the Configuration data package contains equipment configuration information (capability information) for RX200. RX200 may also transmit identification information of the power receiving device 200 to the power transmitting device 100 using the Extended Identification data package (XID Package). Upon receiving the ID data package and Configuration data package signals, TX100 responds with an acknowledgment (ACK). The Configuration phase then ends.

[0050] In the negotiation phase, the GP value is determined based on the GP value requested by RX200 and the power transmission capacity of TX100. TX100 also receives an FOD Status data package from RX200 containing the Reference Quality Factor Value and Reference Resonance Frequency Value. In the Q-value measurement method, the presence or absence of foreign matter is determined based on thresholds derived from the Reference Quality Factor Value and Reference Resonance Frequency Value. TX100 then executes foreign matter detection processing using the Q-value measurement method, as requested by RX200. Furthermore, the WPC standard specifies a method in which, after transitioning to the Power Transfer phase, the RX200 performs the same processing as the Negotiation phase again at its request. The phase in which these processes are performed after transitioning from the Power Transfer phase is called the Renegotiation phase.

[0051] In the Power Transfer phase, TX100 and RX200 perform control for starting and continuing power transmission, error handling, and stopping power transmission upon full charge. TX100 and RX200 perform communication processing for these power transmission and reception control operations. For example, using the transmitting antenna 105 and receiving antenna 205 used for wireless power transmission based on the WPC standard, communication is performed by superimposing a signal onto the electromagnetic waves transmitted from the transmitting antenna 105 or the receiving antenna 205. The range in which communication based on the WPC standard is possible between TX100 and RX200 is the same as the power transmission range of TX100.

[0052] Next, the functions of the control unit of TX100 will be described with reference to Figure 4. Figure 4 is a block diagram showing an example of the functional configuration of the control unit 101 of the power transmission device 100 (TX100). The control unit 101 includes a communication control unit 301, a power transmission control unit 302, a measurement unit 303, a setting unit 304, and a state detection unit 305.

[0053] The communication control unit 301 performs communication control with the RX200 based on the WPC standard via the first communication unit 104, or performs communication control with the RX200 via the second communication unit 109.

[0054] The power transmission control unit 302 controls the power transmission unit 103 to control the power transmission to the RX200.

[0055] The measurement unit 303 measures the power transmitted to the RX200 via the power transmission unit 103 and measures the average transmitted power per unit time. The measurement unit 303 also measures the Quality Factor related to the power transmission antenna 105. The measurement unit 303 also measures the temperature using temperature sensors placed at multiple locations on the TX100. The measurement unit 303 also measures a quantity (e.g., coupling coefficient) that represents the electromagnetic coupling state between the power transmission antenna 105 and the power receiving antenna 205. The quantity representing the electromagnetic coupling state, such as the coupling coefficient, may also be called a coupling state index.

[0056] The setting unit 304 calculates and sets thresholds for foreign object detection in the Q-value measurement method and for foreign object detection in the Power Loss method. The setting unit 304 also calculates and sets thresholds for foreign object detection or for detecting misalignment between TX100 and RX200 based on, for example, the coupling state index between the transmitting antenna 105 and the receiving antenna 205 measured by the measurement unit 303. The setting unit 304 also calculates and sets thresholds for foreign object detection or for detecting misalignment between TX100 and RX200 based on, for example, the temperature of the power transmission device measured by the measurement unit 303.

[0057] The state detection unit 305 performs state detection between the TX100 and the RX200. For example, the state detection unit 305 detects foreign objects present between the TX100 and the RX200, and also detects misalignment between the transmitting antenna 105 and the receiving antenna 205. More specifically, state detection processing can be performed using the Power Loss method, Q-value measurement method, temperature measured in the TX100, and the electromagnetic coupling state (e.g., coupling coefficient) between the transmitting antenna 105 and the receiving antenna 205. The state detection unit 305 can also perform foreign object detection and misalignment detection between the transmitting antenna 105 and the receiving antenna 205 using other methods. For example, in a TX100 equipped with NFC communication functionality, the state detection unit 305 performs state detection processing using the opposing device detection function according to the NFC standard. In addition to detecting the presence or absence of foreign objects and the electromagnetic coupling state between the transmitting and receiving antennas, the state detection unit 305 can also detect changes in the state of the TX100. For example, the state detection unit 305 can detect an increase or decrease in the number of RX200s on the TX100.

[0058] The setting unit 304 sets a threshold value that serves as a criterion for determining the presence or absence of foreign matter when the TX 100 performs state detection. State detection can be, for example, based on the Power Loss method, Q-value measurement method, state detection based on temperature measured in the TX 100, or state detection based on the coupling state index of the transmitting antenna 105 and the receiving antenna 205. The setting unit 304 can also set a determination threshold value necessary for state detection processing using other methods. Based on the threshold value set by the setting unit 304 and the measurement results from the measurement unit 303, the state detection unit 305 can perform foreign matter detection processing and positional misalignment detection processing between the transmitting antenna 105 and the receiving antenna 205. For example, the state detection unit 305 can acquire data such as transmitted power, Quality Factor, temperature measured in the TX 100, and coupling state index of the transmitting antenna 105 and the receiving antenna 205 as measurement results from the measurement unit 303.

[0059] The processes performed by the communication control unit 301, power transmission control unit 302, measurement unit 303, setting unit 304, and state detection unit 305 shown in Figure 4 can be implemented using programs executed by the CPU or other components of the control unit 101. Each process is executed in parallel according to an independent program, while maintaining synchronization between programs through event processing or the like. However, two or more of these processes may be incorporated into a single program.

[0060] Next, an example of the processing flow related to power transmission and reception control performed by TX100 and RX200 will be described. Figure 5 is a flowchart showing an example of power transmission control processing performed by TX100. This processing is realized, for example, by the control unit 101 of TX100 executing a program read from memory 106. This processing may also be performed in response to the power being turned on to TX100, in response to the user of TX100 inputting a command to start a wireless power transmission application, or in response to TX100 being connected to a commercial power source and receiving power. This processing may also be started by other triggers.

[0061] In F501, TX100 performs the processes defined as the Selection and Ping phases of the WPC standard and waits for RX200 to be placed. Specifically, TX100 repeatedly and intermittently transmits Analog Ping according to the WPC standard to detect objects within the power transmission range. For example, TX100 can detect when RX200 or conductive pieces are placed on the charging base 300. If TX100 detects the presence of an object within the power transmission range, it transmits Digital Ping.

[0062] When TX100 receives a predetermined response to Digital Ping, it determines that the detected object is RX200 and that RX200 has been placed on the charging base 300. Here, the "predetermined response" is the Signal Strength (SIG) data packet transmitted by RX200. This packet includes a Signal Strength Value representing the signal strength of the signal received by RX200. The Signal Strength Value is calculated from the following parameters. Specifically, the parameters are the voltage output by the rectifier section (rectifier output voltage) of the power receiving unit 203 measured by RX200, or the voltage of the open circuit including the power receiving antenna 205 measured by RX200 (open circuit voltage), or the power received value measured by RX200, etc.

[0063] Furthermore, before transmitting the Digital Ping, the TX100 measures the Quality Factor related to the transmitting antenna 105. This measurement result is used when performing foreign object detection processing using the Q-value measurement method.

[0064] After the placement of the RX200 is detected, in F502, the TX100 obtains (receives) identification information from the RX200 through communication in the Configuration phase as defined by the WPC standard. In the Configuration phase, the RX200 transmits an Identification data packet (ID Packet) to the TX100. The ID Packet contains the Manufacturer Code and Basic Device ID, which are the identification information for each individual RX200, as well as information elements that can identify the version of the corresponding WPC standard.

[0065] RX200 may transmit identification information of the power receiving device 200 to the power transmitting device 100 using an Extended Identification data package (XID Package). Furthermore, RX200 transmits a Configuration data package to TX100. The Configuration data package contains the following capability information of RX200: - Maximum Power Value or Reference Power, which is a value that identifies the maximum power that RX200 can supply to the load. - Information indicating whether RX200 has the WPC standard Negotiation function. - Parameters used in frequency shift modulation, the communication modulation method used by TX100 when transmitting information to RX200. - Information indicating whether RX200 supports out-of-band communication functionality.

[0066] When TX100 receives the packet from RX200, it sends an acknowledgment (ACK) to RX200, and the Configuration phase ends. Note that TX100 may obtain the identification information of RX200 by a method other than the WPC standard Configuration phase communication. The identification information for each RX200 may be a Wireless Power ID. Alternatively, it may be any other identification information that can identify an individual RX200, such as a Bluetooth Address (hereinafter referred to as "BD_ADDR") unique to the second communication unit 212 of RX200. Note that BD_ADDR is an 8-byte address used in BLE. BD_ADDR is a Public Address defined in the BLE standard, which indicates, for example, the manufacturer of the RX200 or individual identification information of the BLE's communication function (second communication unit 212). BD_ADDR may also be a Random Address.

[0067] Here, RX200 notifies TX100 of the Qi standard power profile information supported by its device, including it in either an ID Packet, XID Packet, or Configuration data pack. RX200 also uses one of these packets to notify TX100 of the parameters necessary for TX100 to estimate, calculate, or determine the coupling state index between TX100's transmitting antenna 105 and RX200's receiving antenna 205. The parameters necessary for estimating, calculating, or determining the coupling state index are, for example, as described later in "Method for Measuring the Coupling State Index Between the Transmitting and Receiving Antennas."

[0068] Upon receiving this notification, the TX100 compares the Qi power profile information supported by the RX200 with the Qi power profile information supported by the TX100 to determine which power profile to use. In this case, MPP will be used as the power profile.

[0069] Next, in F503, TX100 determines the GP through negotiation with RX200 based on the request from RX200 and its own power transmission capacity. In F503, the Negotiation phase of the WPC standard communication takes place. For example, RX200 notifies TX100 of the power value it requests by sending a Specific Request. TX100 decides whether to accept the request based on its own power transmission capacity and other conditions. If TX100 accepts the request, it sends an acknowledgment (ACK) to RX200; if it does not accept the request, it sends a negation (NACK) (also written as NAK) to RX200. The value of the GP determined through negotiation with RX200 is the value requested by RX200 if TX100 accepts the request from RX200. If TX100 does not accept the request from RX200, the GP value may be set to a predetermined value (e.g., 5 watts) as defined in the WPC standard. Also, if TX100 receives information indicating that RX200 does not support the Negotiation phase (e.g., F602 described below), it will not perform Negotiation phase communication and will set the GP value to a predetermined value. The predetermined value is, for example, a value predetermined in the WPC standard (e.g., 5 watts).

[0070] Furthermore, TX100 performs foreign object detection processing using the Q-value measurement method in accordance with a request from RX200. TX100 receives an FOD Status data packet from RX200. This packet includes the Reference Quality Factor Value and Reference Resonance Frequency Value described above. Then, TX100 performs foreign object detection using the Q-value measurement method. This foreign object detection is performed based on the following information: The Quality Factor and resonant frequency of the transmitting antenna 105, measured by TX100 before the transmission of the Digital Ping. - A threshold value based on the Reference Quality Factor Value and Reference Resonance Frequency Value received by TX100 from RX200.

[0071] Subsequently, in F504, TX100 transmits power until the RX200's battery 207 is fully charged. In F504, communication of the Power Transfer phase of the WPC standard takes place. RX200 repeatedly sends Extended Control Error data packets (hereinafter referred to as "XCE data packets") to TX100 at time intervals of t_interval. t_interval is a value defined in the WPC standard, for example, 250 milliseconds. The XCE data packets contain a request for how much to increase or decrease the transmitted power. TX100 adjusts the transmitted power by controlling the current or voltage of the transmitting antenna 105 based on the received XCE data packets. Alternatively, TX100 adjusts the transmitted power by controlling the current or voltage of the transmitting unit 103 based on the received XCE data packets. In other words, the XCE data packet contains parameter data for adjusting the transmitted power. By repeating this process, power transmission at the appropriate power level according to the RX200's requests is performed in near real time.

[0072] When the battery 207 is fully charged, the RX200 sends an End Power Transfer data packet (hereinafter referred to as the "EPT packet") to terminate the Power Transfer phase. The RX200 may send an EPT packet for reasons other than full charge. Also, when the Power Transfer phase is terminated, the TX100 stops supplying power for charging the RX200.

[0073] Furthermore, if TX100 fails to receive the next XCE data packet after a time t_timeout has elapsed since the last XCE data packet was received, it determines that RX200 has been removed from the charging cradle 300. In this case, TX100 terminates the Power Transfer phase. t_timeout is a value defined by the WPC standard, for example, a minimum of 2000 milliseconds and a maximum of 2100 milliseconds.

[0074] RX200 may send packets other than XCE data packets to TX100 during the Power Transfer phase. For example, there is a Charge Status data packet that notifies TX100 of the status of RX200's battery 207.

[0075] This packet contains a Charge Status Value indicating the percentage of charge of the battery 207. When TX100 receives the Charge Status data packet, it notifies the user of the charging status by displaying text or diagrams based on the Charge Status Value, for example, using the UI unit 110. TX100 may receive the Charge Status data packet at any time and may notify the user at any time of its choosing.

[0076] During the Power Transfer phase, TX100 transmits power to RX200 and performs foreign object detection processing using the Power Loss method. In this foreign object detection processing, TX100 calculates the difference between the power loss between TX100 and RX200, which is calculated from the difference between the transmitted power value measured during power transmission and the received power value received from RX200, and a reference power loss. If TX100 determines that this difference is greater than or equal to a threshold, it determines (or judges) that "a foreign object is present" or "there is a possibility that a foreign object is present."

[0077] Referring to Figure 6, an example of the processing flow related to power reception control performed by RX200 will be explained. This processing is achieved, for example, by the control unit 201 of RX200 executing a program read from memory 208.

[0078] In F601, RX200 performs the processes defined as the Selection and Ping phases of the WPC standard and waits for its device to be placed on TX100. RX200 detects that it has been placed on TX100, for example, by detecting a Digital Ping from TX100.

[0079] When RX200 detects that it has been placed on TX100, F602 transmits a signal containing its own identification information to TX100 via ID Packet, Configuration data packet, or XID Packet. Note that the identification information of RX200 may be transmitted by a method other than the communication in the Configuration phase of the WPC standard. In addition, other identification information such as BD_ADDR may be used as long as it is information that can identify each individual RX200. Furthermore, RX200 can transmit information other than identification information to TX100 via F602.

[0080] Next, in F603, RX200 transmits a signal to TX100 containing information about the power values ​​it requests, and negotiates with TX100 to determine the GP. In F603, the Negotiation phase of the WPC standard communication takes place. RX200 transmits an FOD Status data packet to TX100. This packet includes Reference Quality Factor Value and Reference Resonance Frequency Value.

[0081] Next, in F604, RX200 receives power until battery 207 is fully charged. The processing performed by RX200 in this phase is as described above. In the Power Transfer phase, RX200 and TX100 perform foreign object detection processing using the Power Loss method. In F605, RX200 repeatedly transmits XCE data packets at intervals of t_interval, and finally transmits an EPT packet to TX100 to terminate processing.

[0082] Next, the sequence of operations performed by the MPP-enabled RX200 and TX100 will be explained using the sequence diagram shown in Figure 7. The "GET" packets described below are packets used by the RX200 to request specific information from the TX100. The "SRQ" packets are packets used by the RX200 to make simple requests to the TX100.

[0083] When the RX200 is placed on top of the TX100, the TX100 transmits a Digital Ping (hereinafter referred to as D-Ping) using a frequency of 128 kHz (S700).

[0084] When the RX200 receives a 128 kHz D-Ping signal (S700), it sends a Signal Strength (SIG) data packet (SIG packet) to the TX100 (S701). Subsequently, the RX200 sends an ID packet to the TX100 (S702). The ID packet contains the major and minor versions of the standard supported by the RX200.

[0085] Then, RX200 sends an Extended Identification (XID) packet to TX100 (S703). In the XID packet, RX200 stores 0xFE in Bank0 (B0), which indicates the MPP Sub Header (MPP-Selector), thereby informing TX100 that it supports MPP. Upon receiving the XID packet, TX100, which supports MPP, recognizes that RX200 supports MPP.

[0086] Next, RX200 sends a Configuration data packet (CFG packet) to TX100 (S704). Since TX100 supports MPP, and RX200 also supports MPP, TX100 sends an MPP pattern (MPP) to RX200 in response to the CFG packet (S705). In this way, TX100 notifies RX200 that TX100 itself also supports MPP. An MPP pattern is a bit pattern response that is different from ACK and NAK, and is defined in the Qi standard.

[0087] When RX200 receives an MPP pattern, it sends a GRQ(ID) to TX100 requesting identification information (Identifier) ​​from the General Request Packet to the power transmission equipment (S706). When TX100 receives the GRQ(ID), it sends its own Identifier to RX200 (S707). Subsequently, RX200 sends a GET / PTx Extended ID to TX100 to request the transmission of Extended Identification (S708). When TX100 receives the GET / PTx Extended ID, it sends its own XID to RX200 (S709).

[0088] Next, RX200 sends an SRQ / freqsel to TX100 using a Negotiation phase with a frequency of 128 kHz (S710). This causes RX200 to select an operating frequency of 360 kHz and request a change in operating frequency. TX100 sends an ACK to SRQ / freqsel (S711). This causes TX100 to acknowledge the above request for a change in operating frequency.

[0089] TX100 has a function to temporarily stop power transmission and then resume it after a specified delay time (this is EPT / rep, described later). RX200 sends an SRQ / rep packet containing the above delay time to TX100 (S712). If TX100 accepts the delay time, it sends an ACK to RX200 (S713).

[0090] Subsequently, RX200 sends SRQ / en to TX100 requesting the termination of the Negotiation phase using a frequency of 128 kHz (S714). TX100 sends ACK in response to SRQ / en, terminating the Negotiation phase (S715). Subsequently, RX200 sends End Power Transfer / re-ping (EPT / rep) to TX100 (S716). EPT / rep is used to have TX100 resume power transmission after a specified delay time.

[0091] When TX100 receives an EPT / rep, it removes its power signal (stops power transmission) and resumes D-Ping transmission after a specified delay. At this point, when TX100 resumes power transmission, it transmits D-Ping using the 360 ​​kHz frequency selected by RX200 in SRQ / freqsel (S717).

[0092] When RX200 receives power via D-Ping, it sends a SIG packet to TX100 (S718) and then an ID packet (S719). Subsequently, RX200 sends an MPP Extended Identification (MPP-XID) packet to TX100 (S720). The MPP-XID packet contains various parameters. These parameters include the DC output voltage V rectified by the rectifier circuit of RX200. ＲＥＣＴ This includes α, a parameter used to estimate the coupling coefficient. ０ｒｘ (Alpha0 Rx), α ０ｒｘ This includes (Alpha1 Rx) and αk_threhold(Alpha-Kth Rx).

[0093] Next, RX200 transmits a CFG packet to TX100 (S721) and receives an MPP response from TX100 (S722). Upon receiving the MPP response, RX200 transitions to the 360 ​​kHz Negotiation phase.

[0094] RX200 sends a GET / PTX Extended ID (GET / PTX XID) packet to TX100 requesting additional information to identify TX100 (S723). TX100 then sends an Extended Power Transmitter Identification (PTX XID) packet to RX200 (S724). This XID packet contains the device identification information for TX100.

[0095] Next, RX200 transmits an Extended Power Receiver Capabilities (ECAP) packet providing the capabilities information of the power receiving device to TX100 (S725), and receives an ACK from TX100 as a response (S726). Then, RX200 transmits a GET / ECAP packet to TX100 to request the capabilities information of TX100 (S727). TX100 transmits an Extended Power Transmitter Extended Capabilities (ECAP) packet to RX200 (S728).

[0096] Then, RX200 transmits a GET / PLAP packet to TX100 to request the transmission of Power Loss Accounting Parameters (PLAP) (S729). TX100 transmits PLAP to RX200 (S730). The PLAP transmitted by TX100 is the parameter g for calculating the power loss P of the power receiving coil. ｃｏｉｌ ｌｏｓｓ，ＲＸ which includes. Thereafter, RX200 transmits the PLAP of RX200 to TX100 (S731). The PLAP of RX200 includes P ｃｏｉｌ，ＲＸ ＦＭ ｌｏｓｓ and P ｃｏｉｌ ｌｏｓｓ，ＴＸ and the parameters α ＦＭ (Alpha_FM), α ＦＭ，ＤＣ (Alpha_FM_DC) and g ｃｏｉｌ，ＴＸ (g_coil_TX) for calculating. RX200 receives an ACK from TX100 as a response to the PLAP (S732).

[0097] RX200 transmits an SRQ / EGPL packet, which is an Extended Power Level Selection packet for negotiating the power level of the load power, to TX100 (S733). TX100 transmits an ACK to RX200 if it can accept the power level stored in the SRQ / EGPL packet (S734).

[0098] Then, RX200 sends SRQ / en to TX100 (S735). This prompts RX200 to request the end of the Negotiation phase using the 360 ​​kHz frequency. TX100 sends ACK to RX200 in response to SRQ / en, ending the Negotiation phase (S736).

[0099] When the negotiation phase ends, RX200 periodically sends XCE data packets to TX100 that provide feedback (Control Error Value) for the power level required in MPP (S737). TX100 sends an ACK to RX200 if it accepts the voltage change request indicated by the Control Error Value stored in the XCE data packet (S738). RX200 also periodically sends Power Loss Accounting (PLA) packets to TX100, which are used for foreign object detection in MPP (S739). The PLA packets contain Received Power, which is the estimated received power value in RX200, and the power P measured by the rectifier circuit. ＲＥＣＴ The data is stored there. TX100 performs foreign object detection based on the PLA packet. If TX100 determines that there is no foreign object and that power transmission is safe, it sends ACK to RX200 (S740). Then, RX200 sends an End Power Transfer (EPT) data packet to TX100 requesting that power transmission be stopped when charging is complete (S741).

[0100] [About the MPP function Cloak (Claking, Power Pause)] One of the functions of MPP is "Clak". The following explains "Clak" and its challenges.

[0101] "Clok" is a function that allows for the temporary suspension of power transmission (active power transfer) from TX100 to RX200 during the Power Transfer phase described above. The Power Transfer phase may also be called the Power Transfer Stage. Hereafter, the temporary suspension of power transmission from TX100 to RX200 during the Power Transfer phase will also be referred to as "cloaking".

[0102] At this time, the RX200 and TX100 maintain their link, so the suspended power transmission can be resumed at any time without going through the startup flow, Ping phase, and Negotiation phase. In other words, "Clak" is a method of temporarily interrupting power transmission without notifying the user and without resetting the already negotiated Power Transfer contract. The Ping phase and Negotiation phase may also be called the Ping Stage and Negotiation Stage, respectively. The phase in which the RX200 and TX100 perform "Clak" is called the "Clak phase".

[0103] Unlike EPT data packets, the TX100 and RX200 can maintain the already negotiated power transfer contract when initiating and exiting a Cloak. To achieve this, the RX200 requires a power storage element, such as a battery, to retain its state and information when power transmission is interrupted by a Cloak.

[0104] Cloak (Cloking, Power pause) is used in the following cases, for example: • The wireless power system enters Power pause (Cloking) and the RX200 performs an NFC scan. • The wireless power system enters Power pause (Cloking) for temperature management (temperature control, heat dissipation). (If the RX200's battery temperature is too high, Power pause suppresses heat generation and controls the temperature.) • The wireless power system enters Power pause (Cloking) for environmental reasons, such as saving power when the RX200 is fully charged (reducing the power transmitted from the TX100 to the RX200). (If trickle charging at the end of the RX200's charging cycle is inefficient, Power Pause will allow the RX200's battery to discharge further before continuing charging.)

[0105] Here, the wireless power system is a system consisting of the RX200 and TX100.

[0106] The TX100 and RX200 can initiate Cloak at any time during the Power Transfer phase (by entering Cloak). "Initiating Cloak," "entering Cloak," and "initiating Cloak" are used interchangeably.

[0107] Furthermore, RX200 can exit the cloak at any time. TX100 can also request RX200 to exit the cloak at any time. If this request is rejected by RX200 three times, TX100 will remove power and transition to the ping phase.

[0108] The following describes the control of Cloak performed by TX100 and RX200 using Figures 25A, 25B, 26A, and 26B. In Figures 25A, 25B, 26A, and 26B, white boxes with black text indicate packets sent by RX200 to TX100. Similarly, black boxes with white text indicate packets sent by TX100 to RX200.

[0109] The timing chart (sequence, diagram) for when TX100 and RX200 initiate Cloak during the Power Transfer phase will be explained using Figures 25A and 25B.

[0110] Figure 25A shows the sequence (diagram) when RX200 starts Cloak.

[0111] RX200 sends an XCE data packet to TX100. The XCE data packet is as described above. At this time, TX100 and RX200 are in the Power Transfer phase. TX100 responds to the XCE data packet with an ACK to RX200.

[0112] Next, RX200 sends a Cloak Data Packet to TX100. RX200 initiates Cloak by sending the Cloak Data Packet to TX100. From this point onward, TX100 and RX200 enter the Cloak phase. Next, TX100 responds to RX200 with an ACK in response to the Cloak Data Packet.

[0113] Next, TX100 temporarily suspends power transmission to RX200. The duration of the temporary suspension of power transmission is shown in Figures 25A and 25B. ｃｌｏａｋ This is represented by t. Note that the period t during which Cloak temporarily suspends the transmission of power signals from TX100 to RX200 is also specified. ｃｌｏａｋRX200 requests and negotiates with TX100 using SRQ data packets. If RX200 does not make a request and negotiate with TX100 using SRQ data packets, TX100 will be suspended for a period of time. ｃｌｏａｋ Therefore, the maximum value supported by the "Cloak" function, 102.3 seconds, is used. The following is the period during which the transmission of power signals from TX100 to RX200 is temporarily suspended. ｃｌｏａｋ This period is sometimes called the "Cloak time" or "Cloak period." Note that after detecting the cessation of power transmission (removal of the power signal) from the TX100, the RX200 disconnects its load (battery, etc.). Then, for a period of time, the power transmission (Power signal) from the TX100 to the RX200 is temporarily suspended. ｃｌｏａｋ During this time, the RX200 will be kept disconnected from its load (battery, etc.).

[0114] And, ｃｌｏａｋ After a certain period of time, TX100 transmits a Cloak Ping to RX200. The Cloak Ping uses the same configuration as the Digital Ping described above. In other words, there is a period of time during which TX100 temporarily suspends the transmission of power signals to RX200. ｃｌｏａｋ This also represents the period between Cloak Pings. Period t ｃｌｏａｋ This is also called a Cloak Ping Delay, Cloak period, or power interference period. When the RX200 receives a Cloak Ping, it can communicate with the TX100, and the TX100 and RX200 can send and receive packets to each other.

[0115] When RX200 receives a Cloak Ping, if it decides to perform Cloak again, it sends another Cloak Data Packet to TX100. RX200 restarts Cloak by sending another Cloak Data Packet to TX100. Next, TX100 responds to RX200 with an ACK in response to the Cloak Data Packet. Then, TX100 restarts t ｃｌｏａｋ During this period, the transmission of power to the RX200 is temporarily suspended. Then, after the RX200 detects the cessation of power transmission from the TX100 (removal of the power signal), it disconnects the load (battery, etc.) of the RX200 again. Then, the transmission of power (power signal) from the TX100 to the RX200 is temporarily suspended for the period t ｃｌｏａｋ During this time, the RX200 will be disconnected from its load (battery, etc.).

[0116] As described above, after entering the Cloak phase, TX100 performs the following actions with respect to RX200: ｃｌｏａｋ Cloak Ping is transmitted at intervals of [number]. When RX200 receives Cloak Ping from TX100, if it decides to execute Cloak again, it sends Cloak Data Packet to TX100. This allows RX200 (and TX100) to execute Cloak again and temporarily suspend power transmission from TX100 to RX200. In other words, if RX200 wants to continue Cloak, it can achieve this by continuously sending Cloak Data Packet to TX100 when it receives Cloak Ping.

[0117] As shown in Figures 25A and 25B, the interval of the Clock Ping is the rise time of the RX200. ｗａｋｅ Also, the transmission time of the Cloak Data Packet and the window time to terminate power transmission. ｔｅｒｍｉｎａｔｅ It is restricted by.

[0118] Next, t ｃｌｏａｋThis section describes the Detect Ping (Clok Detect Ping) transmitted by TX100 during the specified period. During the period when TX100 temporarily suspends power signal transmission to RX200 due to Cloak, TX100 can transmit Pings at predetermined time intervals. These predetermined time intervals are represented by tcloakdet in Figures 25A and 25B and are called the "Clok Detect Ping Delay". This Ping is a short power ping, achieved by TX100 transmitting power at short time intervals. Even during the period when TX100 temporarily suspends power transmission to RX200 due to Cloak, the Ping allows RX200 to detect the presence of TX100, and TX100 can detect the presence of RX200. This Ping is called a Detect Ping. Furthermore, the predetermined time interval, called the Cloak Detect Ping Delay (tcloakdet), is requested and negotiated by RX200 to TX200 using SRQ data packets. PTX100 also transmits Cloak Detect Pings with a predetermined time width (time interval, duration). The predetermined time width is shown in Figures 25A and 25B as t ｄａｃｔｉｖｅ It is represented as "Clock detects active window".

[0119] The above explains the case where the RX200 starts and continues using Cloak.

[0120] Next, using Figure 25B, we will explain the sequence (diagram) when TX100 starts Cloak.

[0121] RX200 sends an XCE data packet to TX100. The XCE data packet is as described above. At this time, TX100 and RX200 are in the Power Transfer phase. TX100 responds to the XCE data packet with an ATN to RX200. Here, the ATN is a response that has the meaning of Attention, and it is a response that tells TX100 that it wants to communicate with RX200. In other words, TX100 responds with an ATN when it has something it wants to request (convey) to RX200 via communication.

[0122] Next, upon receiving the ATN, RX200 sends a DSR / POLL to TX100. The DSR / POLL is a packet in which RX200 gives TX100 permission to send messages (packets) that TX100 has been holding back to RX200.

[0123] Upon receiving the DSR / POLL, TX100 sends a Cloak Request Data Packet to RX200. The Cloak Request Data Packet is a packet in which TX100 requests RX200 to initiate a cloak.

[0124] Next, RX200 sends a Cloak Data Packet to TX100 in response to the Cloak Request Data Packet. RX200 initiates Cloak by sending the Cloak Data Packet to TX100. From this point onward, TX100 and RX200 enter the Cloak phase. Next, TX100 responds to the Cloak Data Packet with ACK to RX200.

[0125] The operation of TX100 and RX200 after entering the Cloak phase is the same as in Figure 25A, so the explanation is omitted.

[0126] The above describes the case where TX100 requests RX200 to start Cloak, RX200 starts Cloak, and continues Cloak.

[0127] Next, using Figures 26A and 26B, we will explain the sequence (diagram) of when TX100 and RX200 terminate (exit) the Cloak they are running.

[0128] Figure 26A is a sequence (diagram) of when the RX200 terminates (exits) the Cloak. Figure 26A will be explained step by step. Note that "terminating the Cloak" and "exiting the Cloak" are used interchangeably.

[0129] When RX200 receives a Cloak Ping and determines that it should execute a Cloak, it sends a Cloak Data Packet to TX100.

[0130] Then, when TX100 receives a Cloak Data Packet from RX200, it responds with ACK.

[0131] Next, TX100 temporarily suspends power transmission to RX200. The period during which power transmission is suspended is shown in Figure 26A as t ｃｌｏａｋ It is represented as t. ｃｌｏａｋ The operation of TX100 and RX200 during this period is as described with reference to Figures 25A and 25B. ｃｌｏａｋ The Detect Ping transmitted by TX100 during this period is as described with reference to Figures 25A and 25B.

[0132] t ｃｌｏａｋ After a certain amount of time has passed, or t ｃｌｏａｋDuring this time, RX200 decides to terminate the Cloak. In this case, while TX100 is sending Cloak Ping to RX200, RX200 sends a Report packet to TX100. Specifically, this Report packet is a PRx Report [PRx Identification] Packet (REPORT [PRx ID], PRx ID report packet). Upon receiving the PRx Report [PRx Identification] Packet from RX200, TX100 obtains information about RX200's Identification. Then, TX100 sends an ACK to RX200 in response to the Report packet.

[0133] Then, while TX100 is sending a Cloak Ping to RX200, RX200 sends a Get packet to TX100. Specifically, this Get packet is a Get Request [PTx Extended Identification] Packet (GET [PTx XID]). Upon receiving the Get Request [PTx Extended Identification] Packet from RX200, TX100 operates as follows: In other words, TX100 sends a PTx XID data package (PTx Extended Power Transmitter Identification Package) to RX200. This allows TX100 to notify RX200 of additional information necessary to identify TX100.

[0134] The process described above, from when RX200 sends REPORT [PRx ID] to TX100 until TX100 sends PTx XID data pack to RX200, is the process for terminating Cloak. In this specification, this process may be referred to as the "Cloak termination process".

[0135] After completing the Cloak termination process, RX200 and TX100 transition to the Power Transfer phase. RX200 sends an XCE data packet to TX100. Upon receiving the XCE packet, TX100 sends an ACK to RX200 as a response to the XCE data packet.

[0136] The above describes the sequence (diagram) when the RX200 terminates Cloak.

[0137] Next, using Figure 26B, we will explain the sequence (diagram) when TX100 requests RX200 to terminate Cloak, and RX200 terminates Cloak.

[0138] When RX200 receives a Cloak Ping and determines that it should execute a Cloak, it sends a Cloak Data Packet to TX100.

[0139] Then, when TX100 receives a Cloak Data Packet from RX200, it responds with ACK.

[0140] Next, TX100 temporarily suspends power transmission to RX200. The duration of the temporary suspension of power transmission is shown in Figure 26B as t ｃｌｏａｋ It is represented as t. ｃｌｏａｋ The operation of TX100 and RX200 during this period is as described with reference to Figures 25A and 25B. ｃｌｏａｋ The Detect Ping transmitted by TX100 during this period is as described with reference to Figures 25A and 25B.

[0141] t ｃｌｏａｋ After a certain amount of time has passed, or t ｃｌｏａｋ During this time, TX100 decided to request RX200 to terminate Cloak. ｃｌｏａｋ After the specified time has elapsed, RX200 sends a Cloak Data Packet to TX100 while TX100 is sending Cloak Ping to RX200.

[0142] TX100 sends an ATN to RX200 as a response to the Cloak Data Packet while TX100 is sending Cloak Ping to RX200. The packet containing the ATN information indicates that TX100 is requesting RX200 to terminate the Cloak.

[0143] Next, RX200 and TX100 execute the Cloak termination process described above. After completing the Cloak termination process, RX200 and TX100 move to the Power Transfer phase. RX200 sends an XCE data packet to TX100. Upon receiving the XCE packet, TX100 sends an ACK to RX200 as a response to the XCE data packet.

[0144] The above describes the sequence (diagram) when TX100 requests RX200 to terminate Cloak, and when RX200 and TX100 terminate Cloak.

[0145] The above explains the basic functionality of "Clak (Claking, Power Pause)" in MPP under the Qi standard.

[0146] [Challenges in running Cloak] The following challenges exist when running the aforementioned "Clak".

[0147] (When RX200 initiates "Clak") - If RX200 initiates "Clak" for the reasons described above, the period during which TX100 temporarily suspends power signal transmission to RX200 must be set appropriately according to the reasons. However, the method for doing so is not specified and is not clearly defined. - If RX200 initiates "Clak" for the reasons described above, the interval time for Detect Ping transmitted by TX100 during the Cloak must be set appropriately according to the reasons. However, the method for doing so is not specified and is not clearly defined. - If RX200 initiates "Clak" for the reasons described above, the following may occur: That is, before RX200 completes what it wants to achieve by executing "Clak", TX100 may request RX200 to terminate "Clak", and in some cases, it may transition to the Ping phase.

[0148] (When TX100 initiates "Clak") - If TX100 initiates "Clak" for the reasons described above, the period during which TX100 temporarily suspends power signal transmission to RX200 must be set appropriately according to the reasons. However, the method for doing so is not specified and is not clearly defined. - If TX200 initiates "Clak" for the reasons described above, the interval time for Detect Ping transmitted by TX100 during Cloak must be set appropriately according to the reasons. However, the method for doing so is not specified and is not clearly defined. - If TX100 initiates "Clak" for the reasons described above, there is a possibility that RX200 will terminate "Clak" before TX100 can complete what it wants to achieve by executing "Clak".

[0149] The following describes control methods for the TX100 and RX200 to solve these problems.

[0150] More specifically, in this embodiment, the control method for TX100 and RX200 when RX200 initiates Cloak in order to perform an NFC scan will be described in detail below.

[0151] In this specification, expressions such as "TX100 (power transmission unit) temporarily suspends power transmission" or similar expressions may be replaced with expressions such as "RX200 (power receiving unit) temporarily suspends power reception" or similar expressions. Also, in this specification, expressions such as "TX100 (power transmission unit) resumes power transmission" or similar expressions may be replaced with expressions such as "RX200 (power receiving unit) resumes power reception" or similar expressions.

[0152] [When RX200 starts Cloak to perform an NFC scan] Figure 8 is a flowchart showing an example of TX100's processing as an example of TX100 control, and Figure 9 is a flowchart showing an example of RX200's processing as an example of RX200 control. Below, the control of RX200 and TX100 when RX200 starts Cloak to perform an NFC scan will be explained using Figures 8 and 9. In the explanation using Figures 8 and 9, the phases prior to the Power Transfer phase are as described above using Figures 5 and 6, so the explanation will be omitted, and the control from the Power Transfer phase onward will be explained.

[0153] TX100 starts control (F801), and RX200 also starts control (F901). TX100 starts transmitting power in the Power Transfer phase (F802), and RX200 starts receiving power in the Power Transfer phase (F902).

[0154] The RX200 determines (or judges or determines) whether or not to perform an NFC scan (F903). The purpose of performing an NFC scan is to detect whether or not an NFC tag is present between the RX200 and the TX100. For example, the RX200 decides to perform an NFC scan when it detects or determines that the coupling state between the RX200 and the TX100 has deteriorated (for example, the coupling state index has fallen below a predetermined value) using the coupling state index measurement method described later. The RX200 detecting or determining that the coupling state between the RX200 and the TX100 has deteriorated (i.e., the coupling state index is below a predetermined value) is an example of the conditions related to temporary power reception, temporary power transmission, or temporary power transmission and reception being met.

[0155] If power is transmitted from TX100 when RX200 performs an NFC scan, the power transmitted by TX100 may interfere with the polling signal that RX200 transmits during the NFC scan, potentially preventing RX200 from performing the NFC scan accurately. Therefore, if RX200 decides to perform an NFC scan (Yes in F903), it determines an appropriate Cloak time for the NFC scan (F904). If RX200 decides not to perform an NFC scan (No in F903), it returns to F903.

[0156] In F904, RX200 determines the cloak time to be at least longer than a predetermined time required for RX200 to perform and complete an NFC scan. Alternatively, RX200 determines the cloak time according to the number of NFC types that RX200 scans. That is, the more NFC types that RX200 scans, the longer the cloak time will be, and the fewer NFC types that RX200 scans, the shorter the cloak time will be. Alternatively, RX200 determines the cloak time to be a predetermined time during which RX200 can perform an NFC scan. This allows RX200 to perform an NFC scan during the cloak time when TX100 temporarily suspends power transmission.

[0157] Then, after F904, RX200 transmits Cloak time request information, including the Cloak time determined by RX200, to TX100 (F905). Cloak time request information is transmitted from RX200 to TX100 using a Specific Request (SRQ) Data Packet. Specifically, Cloak time request information is transmitted from RX200 to TX100 using the following Specific Request (SRQ) Data Packet: SRQ / cloakl (Specific Request [Clak Ping Delay - Low Byte]).・SRQ / cloak (Specific Request [Cloak Ping Delay - High Byte]).

[0158] The cloak time is split into two request pieces (Low Byte and High Byte) and sent from RX200 to TX100, in order to allow for the setting of a long cloak time.

[0159] In step F803, TX100 determines whether or not it has received Cloak time request information from RX200. If TX100 determines that it has not received Cloak time request information from RX200 (No in F803), it returns to step F803. On the other hand, if TX100 determines that it has received Cloak time request information from RX200 (Yes in F803), it proceeds to step F804.

[0160] TX100 determines whether to accept (approve) the Cloak time request information received from RX200 (F804). If TX100 determines to accept the Cloak time request information received from RX200 (Yes in F804), it sends a signal to RX200 containing ACK information, which means that it accepts (approves) the information (F805).

[0161] On the other hand, if TX100 determines that it will not accept the Cloak time request information received from RX200 (No in F804), it sends a signal to RX200 containing NAK information indicating that it will not accept (not approve) the request (F806), and returns to F803. Alternatively, instead of "sending a signal containing NAK information," TX100 may send no signal at all.

[0162] In F906, RX200 determines whether it has received a packet from TX100 accepting (approving) the Cloak time request. If RX200 determines, after a predetermined time has elapsed, that it has not received a packet from TX100 accepting (approving) the Cloak time request (No in F906), it returns to F904. On the other hand, if RX200 determines that it has received a packet from TX100 accepting (approving) the Cloak time request (Yes in F906), it proceeds to F907.

[0163] The RX200 determines a suitable Detect Ping interval time for performing an NFC scan (F907). In F907, the RX200 sets the Detect Ping interval time tcloakdetect to "0", indicating that Detect Ping is disabled, and prevents the TX100 from transmitting power to Detect Ping. This is to prevent damage to NFC tags if they are present between the TX100 and the RX200. It also prevents Detect Ping from interfering with the polling signal for the NFC scan performed by the RX200 during the Cloak time when the TX100 temporarily suspends power transmission. As a result, the RX200 can perform an NFC scan during the Cloak time when the TX100 temporarily suspends power transmission.

[0164] Then, after F907, RX200 transmits Detect Ping interval time request information, including the Detect Ping interval time determined by RX200, to TX100 (F908). The Detect Ping interval time request information is transmitted from RX200 to TX100 using a Specific Request (SRQ) Data Packet. Specifically, the Detect Ping interval time request information is transmitted from RX200 to TX100 using the following Specific Request (SRQ) Data Packet: ・SRQ / detect (Specific Request [Cloak Detect Ping Delay]).

[0165] In F807, TX100 determines whether or not it has received Detect Ping interval time request information from RX200. If TX100 determines that it has not received Detect Ping interval time request information from RX200 (No in F807), it returns to F807. On the other hand, if TX100 determines that it has received Detect Ping interval time request information from RX200 (Yes in F807), it proceeds to F808.

[0166] TX100 determines whether to accept (approve) the Detect Ping interval time request information received from RX200 (F808). If TX100 determines to accept the Detect Ping interval time request information received from RX200 (Yes in F808), it sends a signal to RX200 containing ACK information, which means acceptance (approval) (F809). On the other hand, if TX100 determines not to accept the Detect Ping interval time request information (No in F808), it sends a signal to RX200 containing NAK information, which means rejection (not approval) (F810), and returns to F807. Alternatively, TX100 may choose not to send any signal instead of sending a signal containing NAK information.

[0167] In F909, RX200 determines whether it has received a packet from TX100 that accepts (approves) the Detect Ping interval time request. If, after a predetermined time has elapsed, RX200 determines that it has not received a packet from TX100 that accepts (approves) the Detect Ping interval time request (F909 is No), it returns to F907.

[0168] On the other hand, if RX200 determines that it has received a packet from TX100 that accepts (approves) the Cloak time request (Yes in F909), it proceeds to F910.

[0169] RX200 sends a packet (F910) to TX100 to initiate a cloak. This packet is a cloak data packet. There are several reasons why RX200 initiates a cloak. The cloak data packet contains a reason code (PRx CLOAK Reason Codes) that indicates why RX200 requests a cloak from TX100 (the reason for the temporary suspension of power transmission).

[0170] Here, the Cloak data packet will be explained using Figures 10A to 10C. The Cloak data packet may also be referred to as a packet for initiating a temporary suspension of power transmission by TX100.

[0171] Figure 10A shows an example of the configuration of a Cloak data package, where reason code information is stored in b0 to b2. Figure 10B shows a list of exemplary reason codes. For example, the following codes exist as reason codes: ・General. ・Forced (code used when the transmission device rejects the Cloak release request (termination request)). ・Overheating restriction (code used when Cloak is requested due to the temperature (heat) of the receiving device). ・Insufficient power (code used when Cloak is requested because the power transmitted from the transmission device falls below a predetermined threshold). ・Coexistence mitigation (code used when Cloak is requested by the receiving device to perform an operation that cannot coexist with the presence of wireless power). ・Charging completion (code used when charging of the receiving device's battery is complete). ・Transmission device started (code used when the transmission device requests Cloak from the receiving device and Cloak is executed). ・Reserved.

[0172] Figure 10C shows a list of exemplary responses from TX100 to a Cloak data packet transmitted by RX200. Examples of responses from TX100 include the following patterns: ・ACK: A response pattern indicating that the power transmission unit agrees to start / continue Cloak. ・NAK: A response pattern that the power transmission unit is not permitted to transmit. ・ND: A response pattern transmitted when the receiving unit uses an unsupported reason code. ・ATN: If transmitted in Cloak state: A response pattern indicating that the power transmission unit is requesting the termination of Cloak. If transmitted in other states: A response pattern indicating that the power transmission unit is requesting communication with the receiving unit before starting Cloak.

[0173] In F910, RX200 transmits a Cloak data packet to TX100 containing information about the reason code for "Coex Mitigation" with Value "4" as shown in Figure 10B. This is because, as mentioned above, wireless power transmission could interfere with the NFC scan performed by RX200. Then, RX200 proceeds to F911.

[0174] In step F811, TX100 determines whether or not it has received a Cloak data packet from RX200, which is a packet for initiating Cloak. If TX100 determines, after a predetermined time has elapsed, that it has not received a Cloak data packet from RX200 (No in F811), it returns to step F811. On the other hand, if TX100 determines that it has received a Cloak data packet from RX200 (Yes in F811), it proceeds to step F812.

[0175] RX200 performs the necessary processing to execute Cloak at F911 and starts Cloak. TX100 performs the necessary processing to execute Cloak at F812 and starts Cloak.

[0176] After starting Cloak at F911, RX200 performs an NFC scan (F912). Next, RX200 determines whether or not it detected an NFC tag based on the results of the NFC scan in F912 (F913). If RX200 determines that it detected an NFC tag (Yes in F913), it sends an End Power Transfer data packet (EPT packet) to TX100 to request that it stop power transmission (F914). Then, RX200 terminates processing (F917). On the other hand, if RX200 determines that it did not detect an NFC tag (No in F913), it sends a packet to TX100 to terminate Cloak (F915). The packets for terminating Cloak are the following two packets. - Report packet (REPORT packets are used by RX200 to report information to TX100). More specifically, this Report packet is PRx Report [PRx Identification] Packet (REPORT [PRx ID]). - GET Request packet (GET data packets are used by RX200 to request specific information from TX100). More specifically, this GET Request packet is Get Request [PTx Extended Identification] Packet (GET [PTx XID]).

[0177] The Report packet and GET Request packet may also be referred to as packets for terminating the temporary suspension of power transmission by TX100. The absence of the aforementioned NFC tag is an example of the conditions for resuming power reception, power transmission, or power transmission / reception being met.

[0178] As described above, in MPP, TX100 can also request RX200 to terminate Cloak. If RX200 rejects this request three times, TX100 stops power transmission and moves to the Ping phase. In this embodiment, if RX200 starts Cloak to perform an NFC scan, it is undesirable for TX100 to request RX200 to terminate Cloak. This is because RX200 must respond to Cloak termination requests from TX100 even though RX200 has not yet finished the NFC scan, resulting in unnecessary processing. Furthermore, if TX100 requests RX200 to terminate Cloak three times even though RX200 has not yet finished the NFC scan, TX100 will stop power transmission and move to the Ping phase, meaning it will be reset.

[0179] To prevent this, when RX200 initiates a Cloak to perform an NFC scan, a trigger is always executed to terminate the Cloak. The trigger for RX200 to terminate the Cloak is the transmission of a packet to terminate the Cloak. Also, when RX200 initiates a Cloak to perform an NFC scan, TX100 is always prevented from executing a trigger to terminate the Cloak. The trigger for TX100 to terminate the Cloak is the transmission of a packet requesting the Cloak to be terminated. For example, the packet sent by RX200 to initiate the Cloak may include information indicating that TX100 is prohibited from requesting RX200 to terminate the Cloak. In this way, RX200 can complete the NFC scan during the Cloak.

[0180] Let's assume that TX100 responds to the Cloak Data Packet sent by RX200 with an ATN packet requesting that Cloak be terminated. In that case, RX200 sends a CLOAK[forced] Cloak data pack to the ATN. A CLOAK[forced] Cloak data pack is a Cloak data pack with a reason code of Value "1" "Clak: Forced (Denied uncloak request)". This Cloak data pack is shown in Figures 10A to 10C. As a result, RX200 rejects TX100's "request to terminate Cloak".

[0181] Furthermore, the fact that "RX200 initiated Cloak in order to perform an NFC scan" can be recognized by the reason code included in the Cloak data package received from RX200 by TX100.

[0182] In F813, TX100 determines whether or not it has received a packet from RX200 to terminate the aforementioned Cloak.

[0183] If TX100 determines that it has received a packet from RX200 to terminate the aforementioned Cloak (Yes in F813), it proceeds to F815. TX100 sends a packet related to TX100's Extended ID (Extended Power Transmitter Identification (PTX XID) packet) to RX200 (F815). Then, TX100 terminates the Cloak, returns to F802, and starts (resumes) power transmission in the Power Transfer phase. At this time, TX100 transitions to the Power Transfer phase and resumes power transmission without going through the Ping phase, Configuration phase, and Negotiation phase described above.

[0184] If TX100 determines that it has not received the packet from RX200 to terminate the aforementioned Cloak (F813 is No), it determines whether or not it has received an EPT packet from RX200 (F814). If TX100 determines that it has received an EPT packet from RX200 (F814 is Yes), it terminates processing (F816). On the other hand, if TX100 determines that it has not received an EPT packet from RX200 (F814 is No), it returns to F812.

[0185] After sending a packet to TX100 at F915 to terminate the Cloak, RX200 proceeds to F916. RX200 receives a packet from TX100 regarding TX100's Extended ID (Extended Power Transmitter Identification (PTX XID) packet) (F916). Then, RX200 terminates the Cloak and returns to F902, starting (resuming) power reception in the Power Transfer phase. At this time, RX200 transitions to the Power Transfer phase and resumes power reception without going through the Ping phase, Configuration phase, and Negotiation phase described above.

[0186] Next, the control of TX100 and RX200 will be explained using the sequence diagram shown in Figure 20.

[0187] TX100 starts processing (S2001). RX200 starts processing (S2002). TX100 and RX200 start transmitting and receiving power during the Power Transfer phase (S2003).

[0188] RX200 decides to perform an NFC scan (S2004). RX200 determines a suitable cloak time for performing the NFC scan (S2005). RX200 transmits cloak time request information to TX100, including a suitable cloak time for performing the NFC scan (S2006). TX100 transmits information to RX200 indicating that it approves the cloak time request information (S2007).

[0189] RX200 determines a suitable Detect Ping interval time for performing an NFC scan (S2008). RX200 sends Detect Ping interval time request information to TX100, including the suitable Detect Ping interval time for performing an NFC scan (S2009). TX100 sends information to RX200 indicating that it approves the Detect Ping interval time request information (S2010).

[0190] RX200 sends a packet to TX100 to initiate Cloak, which includes a code indicating the reason for Cloak execution (S2011). Here, the code indicating the reason for Cloak execution is the reason code for "Coex Mitigation" with Value "4".

[0191] TX100 and RX200 initiate a Cloak during the Cloak phase (S2012). RX200 performs an NFC scan and determines that it did not detect any NF tags (S2013). RX200 sends a packet to TX100 to terminate the Cloak (S2014). TX100 sends a packet to RX200 regarding the PTx XID (S2015). TX100 and RX200 terminate the Cloak and exit the Cloak phase (S2016). TX100 and RX200 begin (restart) power transmission and reception during the Power Transfer phase (S2017).

[0192] [Modified Versions] Next, modified versions of the control methods for the RX200 and TX100 described above will be explained.

[0193] In the control method described above, the control is executed in the following order: 1. RX200 decides to perform an NFC scan. 2. TX100 and RX200 set the "Cloak time and Detect Ping interval time". 3. RX200 sends a "packet to initiate Cloak" to TX100.

[0194] On the other hand, in this modified example, the control may be executed in the order of "1", "3", and "2".

[0195] Furthermore, in the control method described above, the Cloak time is set before the Detect Ping interval time in step "2," but the order of these settings can be reversed.

[0196] Including the above-described modifications, according to this embodiment, by controlling RX200 and TX100 as described above, RX200 can properly perform NFC scans while Cloak is running.

[0197] <Second Embodiment> In the first embodiment, the control of RX200 and TX100 when RX200 starts Cloak in order to perform an NFC scan was described. In this embodiment, the control of RX200 and TX100 when TX100 starts Cloak in order to perform an NFC scan will be described. Note that redundant explanations will be omitted for configurations and processes that are the same as or similar to those in the first embodiment.

[0198] [When TX100 starts Cloak to perform an NFC scan] Figure 11 is a flowchart showing an example of TX100's processing as an example of TX100 control, and Figure 12 is a flowchart showing an example of RX200's processing as an example of RX200 control. Below, the control of RX200 and TX100 when TX100 starts Cloak to perform an NFC scan will be explained using Figures 11 and 12. In the explanation using Figures 11 and 12, the phases prior to the Power Transfer phase are as described above using Figures 5 and 6, so the explanation will be omitted, and the control from the Power Transfer phase onward will be explained.

[0199] TX100 starts control (F1101), and RX200 also starts control (F1201). TX100 starts transmitting power in the Power Transfer phase (F1102), and RX200 starts receiving power in the Power Transfer phase (F1202).

[0200] TX100 determines (or judges or determines) whether or not to perform an NFC scan (F1103). The purpose of performing an NFC scan is to detect whether or not an NFC tag is present between RX200 and TX100. For example, TX100 decides to perform an NFC scan when it detects or determines that the coupling state between RX200 and TX100 has deteriorated (for example, the coupling state index has fallen below a predetermined value) using the coupling state index measurement method described later. TX100 detecting or determining that the coupling state between RX200 and TX100 has deteriorated (i.e., the coupling state index is below a predetermined value) is an example of the conditions related to temporary power reception, temporary power transmission, or temporary power transmission / reception being met.

[0201] When TX100 performs an NFC scan, if power is transmitted from TX100, the power transmitted by TX100 may interfere with the polling signal that TX100 transmits during the NFC scan, potentially preventing TX100 from accurately performing the NFC scan. Therefore, in F1104, TX100 sends a packet to RX200 requesting the start of a Cloak. This packet is a Cloak request data packet. There are several reasons why TX100 requests the start of a Cloak. The Cloak request data packet contains a reason code (PTx End Of Power Reason Codes) indicating the reason why TX100 requests RX200 to start a Cloak (the reason for temporarily suspending power transmission).

[0202] The Cloak request data packet will be explained using Figures 13A and 13B. The Cloak request data packet may also be referred to as a packet for requesting the start of a temporary suspension of power transmission by TX100.

[0203] Figure 13A shows an example configuration of a Cloak request data package (PTx End Of Power Package), where reason code information is stored in b0 to b2. Figure 13B shows a list of exemplary reason codes. For example, the following codes exist as reason codes: ・General. ・Reserved. ・Constraint due to overheating (code used when Cloak is requested due to the temperature (heat) of the power transmission device). ・Insufficient power (code used when Cloak is requested because the power transmission device does not have enough power to transmit to the power receiving device). ・Coexistence mitigation (code used when Cloak is requested when the power transmission device performs an operation that cannot coexist with the presence of wireless power). ・Reserved.

[0204] In F1104, TX100 transmits a Cloak request data packet to RX200 containing information about the reason code for "Coex Mitigation" with Value "4" as shown in Figure 13B. This is because, as mentioned above, wireless power transmission could interfere with the NFC scan performed by TX100. Then, TX100 proceeds to F1105.

[0205] In step F1203, RX200 determines whether or not it has received a Cloak request data packet from TX100, which is a packet requesting the initiation of Cloak. After a predetermined time has elapsed, if RX200 determines that it has not received a Cloak request data packet from TX100 (No in F1203), it returns to step F1203. If RX200 determines that it has received a Cloak request data packet from TX100 (Yes in F1203), it proceeds to step F1204.

[0206] RX200 sends a request to TX100 for time information requested by TX100 regarding the cloak time and detect ping interval time (F1204).

[0207] This request can be fulfilled by RX200 sending a Specific Request (SRQ) Data Packet or a GET data pack (Get Request Packet) to TX100. For example, a GET / PTx Extended ID or GET / ECAP may be used as this Get Request Packet.

[0208] The reason RX200 sends the request is as follows, as explained in the first embodiment: The Cloak time is determined when RX200 requests the Cloak time from TX100 using SRQ / cloakl and SRQ / cloakh, and TX100 acknowledges the request by responding to RX200 with ACK. The Detect Ping interval time is determined when RX200 requests the Detect Ping interval time from TX100 using SRQ / decept, and TX100 acknowledges the request by responding to RX200 with ACK. In this embodiment, since TX100 requests to start Cloak in order to perform an NFC scan, TX100 is aware of the Cloak time and Detect Ping interval time required to perform the NFC scan. Therefore, before RX200 requests the Cloak time and Detect Ping interval time from TX100 using SRQ / cloakl, SRQ / cloakh, and SRQ / detect, RX200 requests the following from TX100: that RX200, before making those requests, sends information about the Cloak time and Detect Ping interval time that TX100 desires (requests), as preliminary information for determining those requests.

[0209] In F1105, TX100 determines whether it has received a request from RX200 for time information regarding the cloak time and detect ping interval time. If TX100 determines that it has not received the request from RX200 after a predetermined time has elapsed (No in F1105), it returns to F1104. On the other hand, if TX100 determines that it has received the request from RX200 (Yes in F1105), it proceeds to F1106.

[0210] Next, TX100 transmits time information requested by TX100 to RX200 regarding the Cloak time and Detect Ping interval time (F1106). This time information is transmitted, for example, included in packets such as the PTx XID data packet or the ECAP Data packet. The PTx XID data packet is also referred to as the PTx Extended Power Transmitter Identification Packet. The ECAP Data Packet is also referred to as the PTx Extended Power Transmitter Extended Capabilities Packet.

[0211] This section describes the information regarding the Cloak time and Detect Ping interval time transmitted in F1106.

[0212] TX100 determines the cloak time to be at least longer than the time it takes for TX100 to perform and complete an NFC scan. Alternatively, TX100 determines the cloak time based on the number of NFC types it scans. That is, the more NFC types TX100 scans, the longer the cloak time it sets, and the fewer NFC types TX100 scans, the shorter the cloak time it sets. Alternatively, TX100 determines the cloak time to be a predetermined time during which TX100 can perform an NFC scan. This allows TX100 to perform an NFC scan during the cloak time when TX100 temporarily suspends power transmission.

[0213] Furthermore, TX100 determines the Detect Ping interval time to a time suitable for performing NFC scans. TX100 sets the Detect Ping interval time tcloakdetect to "0", indicating that Detect Ping is disabled, and prevents TX100 from transmitting power to Detect Ping. This is to prevent damage to NFC tags if they exist between TX100 and RX200. It also prevents Detect Ping from interfering with the polling signals of NFC scans performed by TX100 during the Cloak time when TX100 temporarily suspends power transmission. As a result, TX100 can perform NFC scans during the Cloak time when TX100 temporarily suspends power transmission.

[0214] In F1205, RX200 determines whether it has received the time information requested by TX100 regarding the Cloak time and Detect Ping interval time. If RX200 determines that it has not received the time information from TX100 after a predetermined time has elapsed (No in F1205), it returns to F1204. On the other hand, if RX200 determines that it has received the time information from TX100 (Yes in F1205), it proceeds to F1206.

[0215] The RX200 determines a suitable cloak time for the TX100 to perform an NFC scan (F1206). At this time, the RX200 determines the cloak time based on the "cloak time requested by TX100" information received from TX100 in F1205. That is, the RX200 determines the cloak time at the same time as, or close to, the "cloak time requested by TX100" information received from TX100 in F1205. Here, close time is, for example, a time obtained by multiplying the cloak time requested by TX100 by a value of 0.9 or more but less than 1, or a value greater than 1 and less than or equal to 1.1.

[0216] Then, RX200 transmits Cloak time request information, including the Cloak time determined by RX200, to TX100 (F1207). The Cloak time request information is transmitted from RX200 to TX100 using a Specific Request (SRQ) Data Packet. Specifically, the Cloak time request information is transmitted from RX200 to TX100 using the following Specific Request (SRQ) Data Packet: ・SRQ / cloakl(Specific Request [Clak Ping Delay - Low Byte]).・SRQ / cloak (Specific Request [Cloak Ping Delay - High Byte]).

[0217] The cloak time is split into two request pieces (Low Byte and High Byte) and sent from RX200 to TX100, in order to allow for the setting of a long cloak time.

[0218] In F1107, TX100 determines whether or not it has received Cloak time request information from RX200. If TX100 determines that it has not received Cloak time request information from RX200 (No in F1107), it returns to F1106. On the other hand, if TX100 determines that it has received Cloak time request information from RX200 (Yes in F1107), it proceeds to F1108.

[0219] TX100 determines whether to accept (approve) the Cloak time request information received from RX200 (F1108). If TX100 determines to accept the Cloak time request information received from RX200 (Yes in F1108), it sends a signal to RX200 containing ACK information, which means that it accepts (approves) the information (F1109). On the other hand, if TX100 determines not to accept the Cloak time request information received from RX200 (No in F1108), it sends a signal to RX200 containing NAK information, which means that it does not accept (does not approve) the information (F1110), and returns to F1106.

[0220] Alternatively, instead of "transmitting a signal containing NAK information," the TX100 may choose not to transmit any signal at all.

[0221] In F1208, RX200 determines whether it has received a packet from TX100 accepting (approving) the Cloak time request. If RX200 determines after a predetermined time has elapsed that it has not received a packet from TX100 accepting (approving) the Cloak time request (No in F1208), it returns to F1206. If RX200 determines that it has received a packet from TX100 accepting (approving) the Cloak time request (Yes in F1208), it proceeds to F1209.

[0222] The RX200 determines a suitable Detect Ping interval time for performing an NFC scan (F1209). At this time, the RX200 determines the Cloak time based on the information of "Detect Ping interval time requested by TX100" received from TX100 in F1205. That is, the RX200 determines the Detect Ping interval time to be the same as or close to the information of "Detect Ping interval time requested by TX100" received from TX100 in F1205. Here, close is, for example, a time obtained by multiplying the Detect Ping interval time requested by TX100 by a value of 0.9 or more but less than 1, or a value greater than 1 and less than or equal to 1.1.

[0223] Then, RX200 transmits Detect Ping interval time request information, including the Detect Ping interval time determined by RX200, to TX100 (F1210). The Detect Ping interval time request information is transmitted from RX200 to TX100 using a Specific Request (SRQ) Data Packet. Specifically, the Detect Ping interval time request information is transmitted from RX200 to TX100 using the following Specific Request (SRQ) Data Packet: ・SRQ / detect (Specific Request [Cloak Detect Ping Delay]).

[0224] In F1111, TX100 determines whether or not it has received a Detect Ping interval time request from RX200. If TX100 determines that it has not received a Detect Ping interval time request from RX200 (No in F1111), it returns to F1106. On the other hand, if TX100 determines that it has received a Detect Ping interval time request from RX200 (Yes in F1111), it proceeds to F1112.

[0225] TX100 determines whether to accept (approve) the Detect Ping interval time request information received from RX200 (F1112). If TX100 determines to accept the Detect Ping interval time request information received from RX200 (Yes in F1112), it sends a signal to RX200 containing ACK information, which means acceptance (approval) (F1113). On the other hand, if TX100 determines not to accept the Detect Ping interval time request information (No in F1112), it sends a signal to RX200 containing NAK information, which means rejection (not approval) (F1114), and returns to F1106. Alternatively, TX100 may choose not to send any signal instead of sending a signal containing NAK information.

[0226] In F1211, RX200 determines whether it has received a packet from TX100 accepting (approving) the Detect Ping interval time request. If RX200 determines, after a predetermined time has elapsed, that it has not received a packet from TX100 accepting (approving) the Detect Ping interval time request (No in F1211), it returns to F1209. On the other hand, if RX200 determines that it has received a packet from TX100 accepting (approving) the Cloak time request (Yes in F1211), it proceeds to F1212.

[0227] RX200 sends a packet to TX100 to initiate Cloak (F1212). This packet is a Cloak data packet. As described with reference to Figures 10A to 10C in the first embodiment, the Cloak data packet contains reason codes (PRx CLOAK Reason Codes) indicating the reason why RX200 is requesting Cloak from TX100. In this embodiment, F1104 indicates that TX100 is requesting RX200 to initiate Cloak.

[0228] Therefore, in F1212, RX200 sends the Cloak data package to TX100, including the following reason code: • Power transmission device started (code for when the power transmission device requests Cloak from the power receiving device and Cloak is executed).

[0229] At F1115, TX100 determines whether or not it has received a Cloak data package from RX200. If TX100 determines, after a predetermined time has elapsed, that it has not received a Cloak data package from RX200 (No at F1115), it returns to F1115. On the other hand, if TX100 determines that it has received a Cloak data package from RX200 (Yes at F1115), it proceeds to F1116.

[0230] At F1213, RX200 performs the necessary processing to execute Cloak and starts Cloak. At F1116, TX100 performs the necessary processing to execute Cloak and starts Cloak.

[0231] TX100 starts Cloak at F1116 and then performs an NFC scan (F1117). Next, TX100 determines whether or not an NFC tag was detected based on the results of the NFC scan at F1117 (F1118).

[0232] If TX100 determines that it has detected an NFC tag (Yes in F1118), it moves to the Ping phase (F1119) to stop power supply to RX100 and terminates processing (F1122).

[0233] On the other hand, if TX100 determines that it has not detected an NFC tag (No in F1118), it sends a packet to RX200 requesting that it terminate Cloak (F1120). The "packet requesting to terminate Cloak" is the "ATN" response pattern that TX100 sends periodically to Cloak data packets after Cloak is started in F1116. As explained with reference to Figure 10C, the "ATN" response to the Cloak data packet is a response pattern that indicates TX100 is requesting that Cloak be terminated.

[0234] "ATN" may also be referred to as a packet, etc., requesting the termination of the temporary suspension of power transmission by TX100. The absence of the aforementioned NFC tag is an example of the conditions for resuming power reception, power transmission, or power transmission / reception being met.

[0235] As described above, in MPP, RX200 can also terminate Cloak. However, in this embodiment, if TX100 starts Cloak to perform an NFC scan, it is undesirable for RX200 to terminate Cloak. This is because RX200 terminates Cloak before TX100 has finished the NFC scan, preventing TX100 from completing the NFC scan during Cloak.

[0236] To prevent this, if TX100 requests TX200 to start a Cloak in order for TX200 to perform an NFC scan and TX100 starts a Cloak, TX100 will always execute a trigger to terminate the Cloak. The trigger for TX100 to terminate the Cloak is the transmission of a packet requesting the Cloak to be terminated. Also, if TX100 requests TX100 to start a Cloak in order for TX100 to perform an NFC scan and RX200 will always not execute a trigger to terminate the Cloak. The trigger for RX200 to terminate the Cloak is the transmission of a packet to terminate the Cloak. For example, the packet sent by TX100 requesting the start of a Cloak may include information indicating that RX200 should not terminate the Cloak. In this way, TX100 can complete the NFC scan during the Cloak. Furthermore, the fact that "TX100 requested the initiation of Cloak in order to perform an NFC scan" can be recognized by the reason code contained in the Cloak request data package received from TX100 by RX200.

[0237] In F1214, RX200 determines whether or not it has received a packet (ATN) from TX100 requesting the termination of Cloak.

[0238] If RX200 determines that it has not received a packet (ATN) from TX100 requesting the termination of Cloak after a predetermined time has elapsed (F1214 is No), it proceeds to F1215. RX200 then determines whether the predetermined time has elapsed (F1215). If RX200 determines that the predetermined time has not elapsed (F1215 is No), it returns to F1214. If RX200 determines that the predetermined time has elapsed (F1215 is Yes), it proceeds to F1217 and terminates the process.

[0239] On the other hand, if RX200 determines that it has received a packet (ATN) from TX100 requesting the termination of Cloak (Yes in F1214), it proceeds to the Cloak termination process (F1216). TX200 also proceeds to the Cloak termination process (F1121) after F1120.

[0240] Here, we will explain the Cloak termination process performed by TX100 and RX200.

[0241] TX100 requests the Cloak to be terminated by responding to the Cloak data packet with the "ATN" response pattern (F1120). Upon receiving the "ATN" from TX100 and recognizing the request, RX200 initiates the Cloak termination sequence by sending the following two packets to TX100: • Report packet (REPORT packets are used by RX200 to report information to TX100). More specifically, this Report packet is a PRx Report [PRx Identification] Packet (REPORT [PRx ID]). • GET Request packet (GET data packets are used by RX200 to request specific information from TX100). More specifically, this GET Request packet is a Get Request [PTx Extended Identification] Packet (GET [PTx XID]).

[0242] This concludes the explanation of Cloak's termination process.

[0243] After TX100 executes the Cloak termination process at F1121, it returns to F1102 and starts (restarts) power transmission in the Power Transfer phase. At this time, TX100 transitions to the Power Transfer phase and resumes power transmission without going through the Ping phase, Configuration phase, and Negotiation phase described above.

[0244] Furthermore, after executing the Cloak termination process in F1216, RX200 returns to F1202 and starts (resumes) power reception in the Power Transfer phase. At this time, RX200 transitions to the Power Transfer phase and resumes power reception without going through the Ping phase, Configuration phase, and Negotiation phase described above.

[0245] Next, the control of TX100 and RX200 will be explained using the sequence diagram shown in Figure 21.

[0246] TX100 starts processing (F2101). RX200 starts processing (F2102). TX100 and RX200 start transmitting and receiving power during the Power Transfer phase (S2103).

[0247] TX100 decides to perform an NFC scan (S2104). TX100 sends a packet to RX200 requesting the start of Cloak, which includes a code for the reason for Cloak execution (S2105). Here, the code for the reason for Cloak execution is the reason code for "Coex Mitigation" with Value "4".

[0248] RX200 requests time information from TX100 regarding the cloak time and detect ping interval time (S2106). TX100 transmits the time information requested by TX100 regarding the cloak time and detect ping interval time to RX200 (S2107).

[0249] RX200 determines a suitable cloak time for TX100 to perform an NFC scan (S2108). RX200 transmits cloak time request information to TX100, including the suitable cloak time for TX100 to perform an NFC scan (S2109). TX100 transmits information to RX200 indicating that it approves the cloak time request information (S2110).

[0250] RX200 determines a suitable Detect Ping interval time for TX100 to perform an NFC scan (S2111). RX200 transmits Detect Ping interval time request information to TX100, including the Detect Ping interval time suitable for TX100 to perform an NFC scan (S2112). TX100 transmits information to RX200 indicating that it approves the Detect Ping interval time request information (S2113).

[0251] RX200 sends a packet to TX100 to initiate Cloak, which includes a code indicating the reason for Cloak execution (S2114). Here, the code indicating the reason for Cloak execution is the reason code for "PTx initiated" with Value "6".

[0252] TX100 and RX200 initiate Cloak during the Cloak phase (S2115). TX100 performs an NFC scan and determines that it did not detect any NF tags (S2116). TX100 sends a packet to RX200 requesting that it terminate Cloak (S2117). RX200 sends a packet to TX100 to terminate Cloak (S2118). TX100 sends a packet to RX200 regarding the PTx XID (S2119). TX100 and RX200 terminate Cloak and end the Cloak phase (S2120). TX100 and RX200 begin (restart) power transmission and reception during the Power Transfer phase (S2121).

[0253] [Variations] Next, a variation of the control method for RX200 and TX100 described above will be explained. In the above control method, control is performed in the following order: 1. TX100 decides to perform an NFC scan. 2. TX100 sends a packet to RX200 requesting the start of Cloak. 3. TX100 and RX200 set the Cloak time and Detect Ping interval time. 4. RX200 sends a packet to TX100 to start Cloak.

[0254] On the other hand, in this modified example, the control may be executed in the order of "1", "3", "2", "4". Alternatively, the control may be executed in the order of "1", "2", "4", "3". In this case, at "4", TX100 sends the "ATN" response pattern described with reference to Figure 10C to RX200 in response to the Cloak data packet transmitted by RX200. Then, TX100 and RX200 set the "Cloak time and Detect Ping interval time".

[0255] Furthermore, in the control method described above, the Cloak time is set before the Detect Ping interval time in step "3," but the order of these settings can be reversed.

[0256] Furthermore, in the control method described above, in step "3", RX200 sends a request to TX100 for "time information requested by TX100 regarding the Cloak time and Detect Ping interval time" (F1204). In response, TX100 sends back to RX200 "time information requested by TX100 regarding the Cloak time and Detect Ping interval time" (F1106). However, when the control is performed in the order of "1", "2", and "3", F1204 and F1106 may be omitted.

[0257] In this case, when RX200 receives a Cloak request data packet from TX100, it may determine the Cloak time and Detect Ping interval time based on the packet. As described above, the Cloak request data packet contains a reason code indicating the reason for executing the Cloak, so RX200 can recognize why TX100 is requesting the execution of the Cloak. Therefore, RX200 may determine (set) the Cloak time and Detect Ping interval time necessary to implement the action related to that reason based on the information in the reason code. In this embodiment, the information in this reason code is "Coex Mitigation" of Value "4".

[0258] Including the above-described modification, according to this embodiment, by controlling RX200 and TX100 as described above, TX100 can properly perform NFC scans while Cloak is running.

[0259] <Third Embodiment> In the first embodiment, the control of RX200 and TX100 when RX200 starts Cloak in order to perform an NFC scan was described. In the second embodiment, the control of RX200 and TX100 when TX100 starts Cloak in order to perform an NFC scan was described. In this embodiment, the control of RX200 and TX100 when RX200 starts Cloak in order to perform temperature control (heat suppression) will be described. Note that redundant explanations will be omitted for configurations and processes that are the same as or similar to those in the first or second embodiment.

[0260] [When RX200 starts Cloak to perform temperature control (heat suppression)] Figure 14 is a flowchart showing an example of TX100's processing as an example of TX100's control, and Figure 15 is a flowchart showing an example of RX200's processing as an example of RX200's control. Hereinafter, the control of RX200 and TX100 when RX200 starts Cloak to perform temperature control (heat suppression) will be explained using Figures 14 and 15. In the explanation using Figures 14 and 15, the phases prior to the Power Transfer phase are as described above using Figures 5 and 6, so the explanation will be omitted, and the control from the Power Transfer phase onward will be explained. Also, flow elements in Figures 14 and 15 that have the same role or control as the flow elements in the flowcharts shown in Figures 8 and 9 described in the first embodiment will be given the same reference number and their explanation will be omitted.

[0261] The RX200 determines (or judges or determines) whether or not to perform temperature control (heat suppression) (F1503). The purpose of the RX200 performing temperature control (heat suppression) is to lower the temperature of the RX200 when the temperature reaches a level that affects the performance of the RX200 or a temperature that would damage the RX200. When the RX200 is receiving power wirelessly, heat is generated due to energy loss in the RX200's receiving antenna (coil) 205, the RX200's casing, the RX200's circuit board, etc. Therefore, the RX200 determines in F1503 to perform temperature control (heat suppression) when it detects that the temperature of the RX200 (RX200's battery temperature, circuit board temperature, etc.) has exceeded a predetermined threshold.

[0262] If the RX200 decides to perform temperature control (Yes in F1503), it determines the appropriate cloak time for temperature control (F1504). On the other hand, if the RX200 decides not to perform temperature control (No in F1503), it returns to F1503.

[0263] The RX200 determines the cloak time to be sufficient for the RX200 to dissipate heat (F1504). The RX200 may also determine the cloak time according to the temperature of the RX200. The higher the temperature of the RX200, the longer the cloak time will be set, and the lower the temperature of the RX200, the shorter the cloak time will be set. Alternatively, the RX200 may set the cloak time to a predetermined value that is sufficient for the RX200 to dissipate heat. Alternatively, the RX200 may set the cloak time to a predetermined value that is sufficient for the RX200 to dissipate heat.

[0264] Then, after F1504, RX200 transmits Cloak time request information, including the Cloak time determined by RX200, to TX100 (F1505). The method for transmitting the Cloak time request information is the same as the method described in the first embodiment.

[0265] The RX200 determines a Detect Ping interval time suitable for temperature control (F1507). In F1507, the RX200 sets the Detect Ping interval time tcloakdecept to a value longer than a predetermined value. Alternatively, the RX200 sets the Detect Ping interval time tcloakdecept to "0", indicating that Detect Ping is disabled. This is because frequent Detect Ping transmissions from the TX100 increase the amount of heat generated in the RX200. Alternatively, the RX200 sets the Detect Ping interval time tcloakdecept to a value shorter than a predetermined value. This is so that if RX200 is removed from TX100, TX100 and RX200 can immediately detect or recognize that RX200 has been removed, by TX100 frequently transmitting Detect Ping. This suppresses the transmission of Detect Ping by TX100 during the cloak time when TX100 temporarily stops power transmission, thereby suppressing the overheating of RX200.

[0266] Then, after F1507, RX200 transmits Detect Ping interval time request information, including the Detect Ping interval time determined by RX200, to TX100 (F1508). The method for transmitting the Detect Ping interval time request information is the same as the method described in the first embodiment.

[0267] RX200 sends a packet to TX100 to initiate Cloak (F1510). This packet is a Cloak data packet. The Cloak data packet is as described in the first embodiment.

[0268] In F1510, the RX200 sends a Cloak data packet to the TX100 containing information about the reason code "Thermally constrained" for Value "2" as shown in Figure 10B. This is because, as mentioned above, if the temperature of the RX200 exceeds a predetermined threshold, it may affect the performance of the RX200 or even damage the RX200.

[0269] In step F1411, TX100 determines whether or not it has received a Cloak data packet from RX200, which is a packet for initiating Cloak. If TX100 determines, after a predetermined time has elapsed, that it has not received a Cloak data packet from RX200 (No in F1411), it returns to F1411. On the other hand, if TX100 determines that it has received a Cloak data packet from RX200 (Yes in F1411), it proceeds to F812. At this time, TX100 receives a Cloak data packet containing information about the reason code "Thermally constrained" with Value "2".

[0270] After starting the cloak in F911, RX200 determines whether the temperature has fallen below a predetermined value (for example, the threshold mentioned above) (F1512). If RX200 determines that the temperature has fallen below the predetermined value (Yes in F1512), it proceeds to F915 and sends a packet to TX100 to terminate the cloak. On the other hand, if RX200 determines that the temperature has not fallen below the predetermined value (No in F1512), it proceeds to F1513.

[0271] The RX200 determines whether a predetermined amount of time has elapsed since the start of Cloak (F1513). If the RX200 determines that the predetermined amount of time has not elapsed since the start of Cloak (No in F1513), it returns to F1512. On the other hand, if the RX200 determines that the predetermined amount of time has elapsed since the start of Cloak (Yes in F1513), it proceeds to F914 and sends an EPT packet to the TX100. This is to protect the RX200 because the temperature does not decrease even when Cloak is running.

[0272] RX200 detecting or detecting that the temperature of RX200 has risen above a predetermined threshold (i.e., the temperature of RX200 is above a predetermined threshold) is an example of the conditions for temporary suspension of power reception, temporary suspension of power transmission, or temporary suspension of power transmission and reception being met. RX200 falling below a predetermined value (i.e., below a predetermined value) is an example of the conditions for resuming power reception, resuming power transmission, or resuming power transmission and reception being met.

[0273] As described above, in MPP, TX200 can also request RX200 to terminate Cloak (i.e., it can terminate Cloak). In this embodiment, if RX200 starts Cloak to perform temperature control, it is undesirable for TX100 to terminate Cloak. This is because TX100 will terminate Cloak even though RX200 has not terminated temperature control, making it impossible to lower the temperature of RX200.

[0274] To prevent this, when RX200 starts a Cloak to perform temperature control, it is necessary to always execute a trigger to terminate the Cloak. The trigger for RX200 to terminate the Cloak is the transmission of a packet to terminate the Cloak. Also, when RX200 starts a Cloak to perform temperature control, TX100 is not necessary to execute a trigger to terminate the Cloak. The trigger for TX100 to terminate the Cloak is the transmission of a packet requesting the Cloak to be terminated. For example, the packet sent by RX200 to start the Cloak may include information indicating that TX100 is prohibited from requesting RX200 to terminate the Cloak. Let's assume that TX100 responds to the Cloak Data Packet sent by RX200 with an ATN packet requesting the Cloak to be terminated. In that case, RX200 sends a CLOAK[forced] Cloak data package to ATN. The CLOAK[forced] Cloak data package is a Cloak data package with a reason code of Value "1" "Clak: Forced (Denied uncloak request)". This Cloak data package is shown in Figures 10A to 10C. As a result, RX200 rejects TX100's "request to terminate Cloak". In this way, RX200 can achieve temperature control (heat suppression) through Cloak.

[0275] Next, the control of TX100 and RX200 will be explained using the sequence diagram shown in Figure 22. Note that sequence elements in Figure 22 that perform the same roles and control as those in the sequence diagram shown in Figure 20, which were described in the first embodiment, are given the same reference numerals and their explanations are omitted.

[0276] RX200 decides to perform temperature control (heat suppression) (S2204). RX200 determines a suitable cloak time for performing temperature control (S2205). RX200 transmits cloak time request information, including a suitable cloak time for performing temperature control, to TX100 (S2206).

[0277] RX200 determines a suitable Detect Ping interval time for temperature control (S2208). RX200 transmits Detect Ping interval time request information, including the suitable Detect Ping interval time for temperature control, to TX100 (S2209).

[0278] RX200 sends a packet to TX100 to initiate a Cloak, which includes a code indicating the reason for Cloak execution (S2211). Here, the reason code for Cloak execution is the reason code for Value "2" "Thermally constrained".

[0279] RX200 detects that its temperature has fallen below a predetermined threshold (S2213). Upon detecting that its temperature has fallen below a predetermined threshold, RX200 sends a packet to TX100 to terminate Cloak (S2214).

[0280] [Variations] Next, a variation of the control method for RX200 and TX100 described above will be explained. In the above control method, control is performed in the following order: 1. RX200 decides to perform temperature control. 2. TX100 and RX200 set the "Cloak time and Detect Ping interval time". 3. RX200 sends a "packet to start Cloak" to TX100.

[0281] On the other hand, in this modified example, the control may be executed in the order of "1", "3", and "2".

[0282] Furthermore, in the control method described above, the Cloak time is set before the Detect Ping interval time in step "2," but the order of these settings can be reversed.

[0283] Including the above-mentioned modifications, according to this embodiment, by controlling RX200 and TX100 as described above, RX200 can appropriately perform temperature control (heat generation suppression).

[0284] <Fourth Embodiment> In the third embodiment, the control of RX200 and TX100 when RX200 starts Cloak in order to perform temperature control (heat suppression) was described. In this embodiment, the control of RX200 and TX100 when TX100 starts Cloak in order to perform temperature control (heat suppression) will be described. Note that redundant explanations will be omitted for configurations and processes that are the same as or similar to those in the first, second, or third embodiment.

[0285] [When TX100 starts Cloak to perform temperature control (heat suppression)] Figure 16 is a flowchart showing an example of TX100's processing as an example of TX100 control, and Figure 17 is a flowchart showing an example of RX200's processing as an example of RX200 control. Hereinafter, the control of RX200 and TX100 when TX100 starts Cloak to perform temperature control (heat suppression) will be explained using Figures 16 and 17. In the explanation using Figures 16 and 17, the phases prior to the Power Transfer phase are as described above using Figures 5 and 6, so the explanation will be omitted, and the control from the Power Transfer phase onward will be explained. Also, flow elements in Figures 16 and 17 that have the same role and control as the flow elements in the flowcharts shown in Figures 11 and 12 described in the second embodiment will be given the same reference number and their explanation will be omitted.

[0286] TX100 determines (or judges or determines) whether or not to perform temperature control (heat suppression) (F1603). The purpose of TX100 performing temperature control (heat suppression) is to lower the temperature of TX100 when the temperature reaches a level that would affect the performance of TX100 or damage TX100. When TX100 is transmitting power wirelessly, heat is generated due to energy loss in the TX100's power transmission antenna (coil) 105, the TX100's casing, the TX100's circuit board, etc. Therefore, when TX100 detects that the temperature of TX100 (TX100's power transmission coil temperature, circuit board temperature, etc.) has exceeded a predetermined threshold, it decides to perform temperature control (heat suppression) in F1603.

[0287] If TX100 decides not to perform temperature control (No in F1603), it returns to F1603. On the other hand, if TX100 decides to perform temperature control (Yes in F1603), TX100 sends a packet to RX200 requesting the start of Cloak (F1604). This packet is a Cloak request data packet. The Cloak request data packet is as described in the second embodiment.

[0288] In F1604, TX100 sends a Cloak request data packet to RX200 containing information about the reason code "Thermally constrained" for Value "2" as shown in Figure 13B. This is because, as mentioned above, if the temperature of TX100 exceeds a predetermined threshold, it may affect the performance of TX100 or even damage it.

[0289] In step F1703, RX200 determines whether or not it has received a Cloak request data packet from TX100, which is a packet requesting the initiation of Cloak (F1703). If RX200 determines, after a predetermined time has elapsed, that it has not received a Cloak request data packet from TX100 (No in F1703), it returns to F1703. On the other hand, if RX200 determines that it has received a Cloak request data packet from TX100 (Yes in F1703), it proceeds to F1204. At this time, RX200 receives a Cloak request data packet containing information about the reason code "Thermally constrained" with Value "2".

[0290] In F1606, TX100 transmits time information requested by TX100 to RX200 regarding the cloak time and detect ping interval time. This time information is transmitted, for example, included in packets such as the PTx XID data packet or the ECAP Data packet. The PTx XID data packet is also referred to as the PTx Extended Power Transmitter Identification Packet. Similarly, the ECAP Data Packet is also referred to as the PTx Extended Power Transmitter Extended Capabilities Packet.

[0291] This section describes the information regarding the Cloak time and Detect Ping interval time transmitted in F1606.

[0292] The TX100 determines the Cloak time to be sufficient for the TX100 to dissipate heat. The TX100 may also determine the Cloak time according to the temperature of the TX100. The higher the temperature of the TX100, the longer the Cloak time should be set, and the lower the temperature of the TX100, the shorter the Cloak time should be set. Alternatively, the TX100 may set the Cloak time to a predetermined value that is sufficient for the TX100 to dissipate heat. Alternatively, the TX100 may set the Cloak time to a predetermined value that is sufficient for the TX100 to dissipate heat.

[0293] Furthermore, TX100 may set the Detect Ping interval time tcloakdecept to a value longer than a predetermined value. Alternatively, TX100 may set the Detect Ping interval time tcloakdecept to "0", indicating that Detect Ping is disabled. This is because frequent transmission of Detect Ping from TX100 increases the amount of heat generated in TX100. Alternatively, TX100 may set the Detect Ping interval time tcloakdecept to a value shorter than a predetermined value. This is to allow TX100 and RX200 to immediately detect or realize that RX200 has been removed from TX100 if RX200 is removed due to frequent transmission of Detect Ping. This makes it possible to suppress the transmission of Detect Ping by TX100 during the Cloak period when TX100 temporarily stops power transmission, thereby suppressing heat generation in TX100.

[0294] In F1706, RX200 determines a suitable cloak time for TX100 to perform temperature control (heat suppression). At this time, RX200 determines the cloak time based on the information of "cloak time requested by TX100" received from TX100 in F1205. That is, RX200 determines the cloak time at the same time as or close to the information of "cloak time requested by TX100" received from TX100 in F1205. Here, close time is, for example, a time obtained by multiplying the cloak time requested by TX100 by a value of 0.9 or more but less than 1, or a value greater than 1 and less than or equal to 1.1.

[0295] Then, RX200 transmits Cloak time request information, including the Cloak time determined by RX200, to TX100 (F1707). The method for transmitting the Cloak time request information is the same as the method described in the second embodiment.

[0296] In F1709, RX200 determines a Detect Ping interval time suitable for TX100 to perform temperature control (heat suppression). At this time, RX200 determines the Cloak time based on the information of "Detect Ping interval time requested by TX100" received from TX100 in F1205. That is, RX200 determines the Detect Ping interval time at the same time as or close to the information of "Detect Ping interval time requested by TX100" received from TX100 in F1205. Here, close time is, for example, a time obtained by multiplying the Detect Ping interval time requested by TX100 by a value of 0.9 or more but less than 1, or a value greater than 1 and less than or equal to 1.1.

[0297] Then, RX200 transmits Detect Ping interval time request information, including the Detect Ping interval time determined by RX200, to TX100 (F1710). The method for transmitting the Detect Ping interval time request information is the same as the method described in the second embodiment.

[0298] After TX100 starts Cloak at F1116, it determines whether the temperature of TX100 has fallen below a predetermined value (for example, the threshold mentioned above) (F1617). If TX100 determines that the temperature of TX100 has fallen below the predetermined value (Yes at F1617), it proceeds to F1120 and sends a packet to RX200 requesting that Cloak be terminated. On the other hand, if TX100 determines that the temperature of TX100 has not fallen below the predetermined value, it proceeds to F1618.

[0299] TX100 determines whether a predetermined time has elapsed since the start of Cloak (F1618). If TX100 determines that the predetermined time has not elapsed since the start of Cloak (No in F1618), it returns to F1618. On the other hand, if TX100 determines that the predetermined time has elapsed since the start of Cloak (Yes in F1618), it moves to the Ping phase to stop power supply to RX100 (F1119) and terminates the process (F1122).

[0300] TX100 detecting or detecting that the temperature of TX100 has risen above a predetermined threshold (i.e., the temperature of TX100 is above a predetermined threshold) is an example of the conditions for temporary suspension of power reception, temporary suspension of power transmission, or temporary suspension of power transmission and reception being met. TX100 falling below a predetermined value (i.e., below a predetermined value) is an example of the conditions for resuming power reception, resuming power transmission, or resuming power transmission and reception being met.

[0301] As described above, in MPP, RX200 can also terminate Cloak. However, in this embodiment, if TX100 starts Cloak to perform temperature control (heat suppression), it is undesirable for RX200 to terminate Cloak. This is because RX200 terminates Cloak even though TX100's temperature control (heat suppression) has not finished, making it impossible to lower the temperature of TX100 below a predetermined value.

[0302] To prevent this, when TX100 requests TX200 to start Cloak in order for TX200 to perform temperature control and TX200 starts Cloak, TX100 is always configured to execute a trigger to terminate Cloak. The trigger for TX100 to terminate Cloak is the transmission of a packet requesting that Cloak be terminated. Also, when TX100 requests TX100 to start Cloak in order for TX100 to perform temperature control and RX200 is always configured not to execute a trigger to terminate Cloak. The trigger for RX200 to terminate Cloak is the transmission of a packet to terminate Cloak. For example, the packet sent by TX100 requesting the start of Cloak may include information indicating that RX200 should not terminate Cloak. In this way, TX100 can perform temperature control (heat suppression) by Cloak. Furthermore, the fact that "TX100 requested the start of Cloak in order to perform temperature control (heat suppression)" can be recognized by the reason code contained in the Cloak request data package received from TX100 by RX200.

[0303] Next, the control of TX100 and RX200 will be explained using the sequence diagram shown in Figure 23. Note that sequence elements in Figure 23 that perform the same role and control as those in the sequence diagram shown in Figure 21, which were described in the second embodiment, are given the same reference numerals and their explanations are omitted.

[0304] TX100 decides to perform temperature control (heat suppression) (S2304). TX100 sends a packet to RX200 requesting the start of Cloak, which includes a code for the reason for Cloak execution (S2305). Here, the code for the reason for Cloak execution is the reason code for Value "2" "Thermally constrained".

[0305] TX100 transmits the requested time information regarding the Cloak time and Detect Ping interval time to RX200 (S2307).

[0306] RX200 determines a suitable cloak time for TX100 to perform temperature control (S2308). RX200 transmits cloak time request information to TX100, including a suitable cloak time for TX100 to perform temperature control (S2309).

[0307] RX200 determines a Detect Ping interval time suitable for TX100 to perform temperature control (S2311). RX200 transmits Detect Ping interval time request information to TX100, including the Detect Ping interval time suitable for TX100 to perform temperature control (S2312).

[0308] TX100 detects that the temperature of RX200 has fallen below a predetermined threshold (S2316). Upon detecting that the temperature of TX100 has fallen below a predetermined threshold, TX100 sends a packet to RX200 requesting that it terminate Cloak (S2317).

[0309] [Variations] Next, a variation of the control method for RX200 and TX100 described above will be explained. In the above control method, control is performed in the following order: 1. TX100 decides to perform temperature control (heat suppression). 2. TX100 sends a packet to RX200 requesting the start of Cloak. 3. TX100 and RX200 set the Cloak time and Detect Ping interval time. 4. RX200 sends a packet to TX100 to start Cloak.

[0310] On the other hand, in this modified example, the control may be executed in the order of "1", "3", "2", "4". Alternatively, the control may be executed in the order of "1", "2", "4", "3". In this case, at "4", TX100 sends the "ATN" response pattern described with reference to Figure 10C to RX200 in response to the Cloak data packet transmitted by RX200. Then, TX100 and RX200 set the "Cloak time and Detect Ping interval time".

[0311] Furthermore, in the control method described above, the Cloak time is set before the Detect Ping interval time in step "3," but the order of these settings can be reversed.

[0312] Furthermore, in the control method described above, in step "3", RX200 sends a request to TX100 for "time information requested by TX100 regarding the Cloak time and Detect Ping interval time" (F1204). In response, TX100 sends back to RX200 "time information requested by TX100 regarding the Cloak time and Detect Ping interval time" (F1606). However, when the control is performed in the order of "1", "2", and "3", F1204 and F1606 may be omitted.

[0313] In this case, when RX200 receives a Cloak request data packet from TX100, it may determine the Cloak time and Detect Ping interval time based on the packet. As described above, the Cloak request data packet contains a reason code indicating the reason for executing the Cloak, so RX200 can recognize why TX100 is requesting the execution of the Cloak. Therefore, based on the information in the reason code, RX200 may determine (set) the Cloak time and Detect Ping interval time necessary to implement the action related to that reason. In this embodiment, the information in this reason code is "Thermally constrained" with Value "2".

[0314] Including the above-mentioned modifications, according to this embodiment, by controlling RX200 and TX100 as described above, TX100 can appropriately perform temperature control (heat suppression) by executing Cloak.

[0315] <Fifth Embodiment> In this embodiment, the control of RX200 and TX100 when RX200 starts Cloak in order to perform power saving (receiving power limiting) with respect to the power that RX200 receives from TX100 will be described. Note that redundant explanations will be omitted for configurations and processes that are the same as or similar to those in the first, second, third, or fourth embodiment.

[0316] [When RX200 starts Cloak to perform power saving (receiving power limit) for the power RX200 receives from TX100] Figure 18 is a flowchart showing an example of TX100's processing as an example of TX100 control, and Figure 19 is a flowchart showing an example of RX200's processing as an example of RX200 control. Below, the control of RX200 and TX100 when RX200 starts Cloak to perform power saving (receiving power limit) for the power RX200 receives from TX100 will be explained using Figures 18 and 19. In the explanation using Figures 18 and 19, the phases prior to the Power Transfer phase are as described above using Figures 5 and 6, so the explanation will be omitted, and the control from the Power Transfer phase onward will be explained. Furthermore, the flow elements in Figures 18 and 19 that perform the same roles and control as the flow elements in the flowcharts shown in Figures 8 and 9 described in the first embodiment are given the same reference numerals and their descriptions are omitted.

[0317] The RX200 determines (or judges or determines) whether or not to perform power saving with respect to the power it receives from the TX100 (F1903). The purpose of the RX200 performing power saving with respect to the power it receives from the TX100 will be explained below.

[0318] Generally, when the power receiving device (RX200) is nearly fully charged (when the battery's charge level (State of Charge) exceeds a predetermined threshold), it operates as follows: The power receiving device (RX200) starts trickle charging, which constantly charges the battery with a small current to compensate for its natural discharge. However, depending on the state of the power receiving device, this trickle charging may be inefficient, and it may be preferable to allow the battery to discharge further and continue charging (receiving power from the power transmitting device) only after the battery's charge level falls below a predetermined threshold. Therefore, in such cases, the RX200 performs power saving on the power received from the TX100.

[0319] When the RX200 detects that its battery capacity exceeds a predetermined threshold, F1903 decides to perform power saving on the power received from the TX100.

[0320] If RX200 decides to perform power saving on the power received from TX100 (Yes in F1903), it determines the appropriate cloak time for power saving on the power received from TX100 (F1904). On the other hand, if RX200 decides not to perform power saving on the power received from TX100 (No in F1903), it returns to F1903.

[0321] The RX200 determines the cloak time to be long enough to perform power saving with respect to the power received from the TX100 (F1904). The RX200 may determine the cloak time to a predetermined value set to perform power saving with respect to the power received from the TX100. Alternatively, the RX200 sets the cloak time to be longer the higher the charge level of the RX200's battery, and shorter the cloak time to be shorter the lower the charge level of the RX200's battery. Alternatively, since the purpose of performing cloak is to wait for the RX200's battery to discharge before restarting power transmission, the RX200 sets the cloak time to be long enough for the RX200 to discharge its battery.

[0322] Then, after F1904, RX200 transmits Cloak time request information, including the Cloak time determined by RX200, to TX100 (F1905). The method for transmitting the Cloak time request information is the same as the method described in the first embodiment.

[0323] The RX200 determines a Detect Ping interval time suitable for power saving with respect to the power received from the TX100 (F1907). In F1907, the RX200 sets the Detect Ping interval time to a value longer than a predetermined value or to "0". This is because if Detect Ping is frequently transmitted from the TX100, the RX200 consumes power by executing the processing when it receives a Detect Ping, causing the battery charge level to drop prematurely. This makes it possible to suppress the transmission of Detect Ping by the TX100 during the Cloak time when the TX100 temporarily stops transmitting power, thereby suppressing the premature drop in the battery charge level. Alternatively, the RX100 sets the Detect Ping interval time tcloakdetect to a value shorter than a predetermined value. This is so that if RX200 is removed from TX100, TX100 and RX200 can immediately detect or become aware of the removal by frequently sending Detect Pings.

[0324] Then, after F1907, RX200 transmits Detect Ping interval time request information, including the Detect Ping interval time determined by RX200, to TX100 (F1908). The method for transmitting the Detect Ping interval time request information is the same as the method described in the first embodiment.

[0325] RX200 sends a packet to TX100 to initiate Cloak (F1910). This packet is a Cloak data packet. The Cloak data packet is as described in the first embodiment.

[0326] In F1910, RX200 transmits a Cloak data pack to TX100 containing information about the reason code "End of Charge" for Value "5" as shown in Figure 10B. This is because, as mentioned above, it is preferable to continue charging (receiving power from TX100) only after the RX200's battery has been further discharged and the battery charge level has fallen below a predetermined threshold.

[0327] In step F1811, TX100 determines whether or not it has received a Cloak data packet from RX200, which is a packet for initiating Cloak. If TX100 determines, after a predetermined time has elapsed, that it has not received a Cloak data packet from RX200 (No in F1811), it returns to F1811. On the other hand, if TX100 determines that it has received a Cloak data packet from RX200 (Yes in F1811), it proceeds to F812. At this time, TX100 receives a Cloak data packet containing information about the reason code "End of Charge" for Value "5".

[0328] After starting Cloak in F911, RX200 determines whether the charge level of its battery has fallen below a predetermined first threshold (F1912). If RX200 determines that the charge level of its battery has fallen below a predetermined first threshold (Yes in F1912), it proceeds to F915 and sends a packet to TX100 to terminate Cloak. On the other hand, if RX200 determines that the charge level of its battery has not fallen below a predetermined first threshold (No in F1912), it proceeds to F1913.

[0329] The RX200 determines whether the charge level of its battery is above a predetermined second threshold (a threshold greater than the first threshold, used for determining "fully charged") (F1913). If the RX200 determines that the charge level of its battery is not above the predetermined second threshold (No in F1913), it returns to F1912. On the other hand, if the RX200 determines that the charge level of its battery is above the predetermined second threshold (Yes in F1913), it proceeds to F914 and sends an EPT packet to the TX100. This is because the RX200 determines that charging is complete since the battery charge level is above the second threshold for determining "fully charged," and notifies the user that charging is complete.

[0330] The fact that the battery charge level of the RX200 described above exceeds a predetermined (first) threshold is an example of the conditions for temporary suspension of power reception, temporary suspension of power transmission, or temporary suspension of power transmission and reception being met.

[0331] The fact that the battery charge level of the RX200 described above is below a predetermined (first) threshold is an example of the conditions for resuming power reception, power transmission, or power transmission / reception being met.

[0332] As mentioned above, in MPP, TX200 can also terminate Cloak (i.e., it can terminate Cloak). In this embodiment, if RX200 starts Cloak to perform power saving on the power it receives from TX100, it is undesirable for TX100 to terminate Cloak. This is because, even though RX200 is performing power saving on the power it receives from TX100, TX100 terminates Cloak and resumes supplying power to RX200.

[0333] To prevent this, when RX200 initiates a cloak to perform power saving on the power it receives from TX100, a trigger is always executed to terminate the cloak. The trigger for RX200 to terminate the cloak is the transmission of a packet to terminate the cloak. Also, when RX200 initiates a cloak to perform power saving on the power it receives from TX100, TX100 is always prevented from executing a trigger to terminate the cloak. The trigger for TX100 to terminate the cloak is the transmission of a packet requesting the termination of the cloak. For example, the packet sent by RX200 to initiate the cloak may include information indicating that TX100 is prohibited from requesting RX200 to terminate the cloak. Let's assume that TX100 responds to the Cloak Data Packet sent by RX200 with an ATN packet requesting that Cloak be terminated. In that case, RX200 sends a CLOAK[forced] Cloak data pack to the ATN. A CLOAK[forced] Cloak data pack is a Cloak data pack with a reason code of Value "1" "Clak: Forced (Denied uncloak request)". This Cloak data pack is shown in Figures 10A to 10C. As a result, RX200 rejects TX100's "request to terminate Cloak". In this way, the RX200 can implement power saving for the power it receives from the TX100 via Cloak.

[0334] Next, the control of TX100 and RX200 will be explained using the sequence diagram shown in Figure 24. Note that sequence elements in Figure 24 that perform the same role and control as those in the sequence diagram shown in Figure 20, which was explained in the first embodiment, are given the same reference numerals and their explanations are omitted.

[0335] RX200 decides to perform power saving with respect to the power received from TX100 (S2404). RX200 determines a suitable cloak time for performing power saving (S2405). RX200 transmits cloak time request information, including a suitable cloak time for performing power saving, to TX100 (S2406).

[0336] RX200 determines a suitable Detect Ping interval time for power saving (S2408). RX200 sends TX100 Detect Ping interval time request information, including the suitable Detect Ping interval time for power saving (S2409).

[0337] RX200 sends a packet to TX100 to initiate a Cloak, which includes a code indicating the reason for Cloak execution (S2411). Here, the reason code for Cloak execution is the reason code for Value "5" "End of Charge".

[0338] RX200 performs power saving and detects that the charge level of RX200's battery has fallen below a first threshold (S2413). Upon detecting that the charge level of RX200's battery has fallen below a first threshold, RX200 sends a packet to TX100 to terminate Cloak (S2414).

[0339] [Variations] Next, a variation of the control method for RX200 and TX100 described above will be explained. In the above control method, the control is performed in the following order: 1. RX200 decides to perform power saving with respect to the power received from TX100. 2. TX100 and RX200 set the "Cloak time and Detect Ping interval time". 3. RX200 sends a "packet to start Cloak" to TX100.

[0340] On the other hand, in this modified example, the control may be executed in the order of "1", "3", and "2".

[0341] Furthermore, in the control method described above, the Cloak time is set before the Detect Ping interval time in step "2," but the order of these settings can be reversed.

[0342] Including the above-described modification, according to this embodiment, by controlling RX200 and TX100 as described above, RX200 can appropriately perform power saving with respect to the power received from TX100.

[0343] <Sixth Embodiment> The first and second embodiments described control for executing Cloak when TX100 or RX200 performs an NFC scan. The third and fourth embodiments described control for executing Cloak when TX100 or RX200 performs temperature control (heat suppression). The fifth embodiment described control for executing Cloak when RX200 performs power saving.

[0344] The control of TX100 and RX200 in the first to fifth embodiments described above becomes increasingly important as the power transmitted from TX100 to RX200 during the Power Transfer phase increases, and the execution of such control is required. This is because, when performing an NFC scan, if Cloak is not properly executed, the NFC tag, if present between TX100 and RX200, will be damaged by the large amount of power. Similarly, when performing temperature control (heat suppression), if Cloak is not properly executed, the large amount of power will cause the temperature of TX100 and / or RX200 to rise. Furthermore, when performing power saving, if Cloak is not properly executed, the large amount of power will prevent RX200 from saving power.

[0345] Therefore, in this embodiment, when TX100 performs high-power rapid charging to RX200, a method will be described in which TX100 and RX200 perform the control described in the first to fifth embodiments of the first embodiment described above.

[0346] The following describes the measurement method for the "coupling state index," which is used as a condition for switching to rapid charging mode.

[0347] [Measurement Method for the Coupling State Index Between Transmitting and Receiving Antennas] This section explains the measurement method for the coupling state index between a transmitting antenna and a receiving antenna. In wireless power transmission, power is transmitted by electromagnetically coupling a transmitting antenna 105 and a receiving antenna 205. By passing an alternating current through the transmitting antenna 105, a voltage is induced in the receiving antenna 205 by changing the magnetic flux passing through the receiving antenna 205. Regarding the coupling coefficient (denoted as k or k value), which is an index representing the coupling state between the transmitting and receiving antennas, for example, when all (100%) of the magnetic flux generated by the transmitting antenna passes through the receiving antenna, it becomes "k = 1". Also, when 70% of the magnetic flux generated by the transmitting antenna passes through the receiving antenna, it becomes "k = 0.7". In this case, the remaining (30%) of the magnetic flux generated by the transmitting antenna becomes leakage flux. This is the magnetic flux generated by the transmitting antenna that did not pass through the receiving antenna. Therefore, when the coupling between the transmitting and receiving antennas is good and the k value is large, the power transmission efficiency from TX100 to RX200 is high. Conversely, when the coupling is not good and the k value is small, the power transmission efficiency from TX100 to RX200 is low.

[0348] Factors that cause a decrease in the coupling coefficient include the presence of foreign objects (such as metal fragments) between the transmitting and receiving antennas, and misalignment between the transmitting and receiving antennas. Alternatively, an increase in the distance between the transmitting and receiving antennas can be a contributing factor. If foreign objects are present between the transmitting and receiving antennas, heat may be generated in the foreign objects. Furthermore, misalignment or separation between the transmitting and receiving antennas increases leakage flux, which can generate significant noise in the surrounding environment. When the k value is small, appropriate control is necessary to achieve safer and higher-quality wireless power transmission. In this embodiment, in order to improve the detection accuracy of foreign objects and the detection accuracy when misalignment or distance (separation) is large, TX100 and / or RX200 perform a process to detect, calculate, or determine the coupling state (including the coupling coefficient) between the transmitting and receiving antennas.

[0349] Referring to Figure 27, the method for measuring the coupling state index between the transmitting antenna and the receiving antenna will be explained. Figure 27 is an equivalent circuit diagram illustrating an example of a measurement method for measuring the coupling state index. The definitions of various quantities related to the primary side (TX100) transmitting antenna (transmitting coil) are shown below. ・r1: Winding resistance of the transmitting antenna. ・L1: Self-inductance of the transmitting antenna. ・V1: Transmission voltage (input voltage) applied to the transmitting antenna as measured by TX100.

[0350] Furthermore, the definitions of various quantities related to the receiving antenna (receiving coil) on the secondary side (RX200) are shown below: • r2: Winding resistance of the receiving antenna. • L2: Self-inductance of the receiving antenna. • V2: Receiving voltage (output voltage) applied to the receiving antenna as measured by RX200.

[0351] The coupling coefficient k between the transmitting antenna and the receiving antenna can be calculated using the following equation 1: k = (V2 / V1) * √(L1 / L2) (Equation 1) Note that the value of the coupling coefficient k is sometimes called the "k value".

[0352] When TX100 calculates the coupling coefficient k, RX200 notifies TX100 of the measured receiving voltage V2 and the value of the self-inductance L2 of the receiving antenna, which RX200 has stored in advance. TX100 calculates the k value using the measured transmitting voltage V1, the value of the self-inductance L1 of the transmitting antenna, which RX200 has stored in advance, and the receiving voltage V2 and self-inductance L2 values ​​received from RX200. Alternatively, RX200 notifies TX100 of a constant calculated using all or either L1 and L2, and V2. Then, TX100 can calculate the k value using the constant and V2 received from RX200 and the transmitting voltage V1 measured by TX100.

[0353] On the other hand, when RX200 calculates the coupling coefficient k, TX100 notifies RX200 of the measured transmission voltage V1 and the pre-stored value of the transmission antenna's self-inductance L1. RX200 calculates the k value using the measured receiving voltage V2, the pre-stored value of the receiving antenna's self-inductance L2, and the transmission voltage V1 and self-inductance L1 values ​​received from TX100. Alternatively, TX100 notifies RX200 of a constant calculated using all or either L1 and L2, and V1. RX200 can then calculate the k value using the constant and V1 received from TX100 and the receiving voltage V2 measured by RX200.

[0354] The transmission voltage V1 is either actually measured by the TX100 at the voltage applied to the transmission antenna, or calculated by the TX100 from the set value of the transmission power. Alternatively, the transmission voltage V1 may be set to the transmission voltage setting value at the time of transmission. Furthermore, the transmission voltage V1 applied to the transmission antenna can be determined from the transmission voltage (denoted as V3) applied to the circuit (e.g., inverter) of the transmission unit 103 of the TX100 and the voltage across the resonant capacitor 107. Here, the transmission voltage V3 applied to the circuit of the transmission unit 103 of the TX100 is, for example, the inverter input voltage input to the inverter of the transmission unit 103 of the TX100, or the inverter output voltage output of the inverter. In this case, the transmission voltage V3 may also be calculated by the TX100 from the set value of the transmission power. Alternatively, the TX100 may actually measure the transmission voltage V3 and the voltage across the resonant capacitor 107 and use them to determine the transmission voltage V1. Alternatively, TX100 may transmit the measured transmission voltage V3 and the voltage across the resonant capacitor 107 to RX200. RX200 may then calculate the k value by determining the transmission voltage V1 using the received voltage values.

[0355] Furthermore, when TX100 or RX200 performs the coupling state index measurement method, RX200 may control the third switch unit 213 to OFF so that the terminals of the receiving antenna 205 are open. This makes it possible to open both ends of the receiving antenna, as shown in Figure 27. In the coupling state index measurement method, since there is no influence from the resonant capacitor 211, the receiving unit 203, the charging unit 206, and the battery 207, it becomes possible to measure the coupling coefficient k with higher accuracy. In addition, the receiving voltage V2 applied to the receiving antenna 205 can be determined from the receiving voltage (denoted as V4) applied to the circuit (e.g., the rectifier) ​​of the receiving unit 203 of RX200 and the voltage applied across the resonant capacitor 211. Here, the receiving voltage V4 applied to the circuit of the receiving unit 203 of RX200 is, for example, the rectifier input voltage input to the rectifier of the receiving unit 203 of RX200. Alternatively, the receiving voltage V2 applied to the receiving antenna 205 can be determined from the receiving voltage (denoted as V5) of the circuit (e.g., the rectifier) ​​of the receiving unit 203 of the RX200 and the voltage across the resonant capacitor 211. Here, the receiving voltage V5 applied to the circuit of the receiving unit 203 of the RX200 is, for example, the rectifier output voltage output from the rectifier of the receiving unit 203 of the RX200. In this case, the RX200 may actually measure the receiving voltage V4 and the voltage across the resonant capacitor 211 and use them to determine the receiving voltage V2. Alternatively, the RX200 may actually measure the receiving voltage V5 and the voltage across the resonant capacitor 211 and use them to determine the receiving voltage V2. Alternatively, the RX200 may transmit the measured receiving voltage V4 and the voltage across the resonant capacitor 211 to the TX100. The k value may be calculated by TX100 determining the receiving voltage V2 using the received voltage value. Alternatively, RX200 may transmit the measured receiving voltage V5 and the voltage across the resonant capacitor 211 to TX100. The k value may then be calculated by TX100 determining the receiving voltage V2 using the received voltage value.

[0356] Alternatively, when TX100 or RX200 performs the coupling state index measurement method, RX200 may be controlled to be in a light load state or a load-connected state. By keeping the load state of RX200 constant, it becomes possible to measure the coupling coefficient k with higher accuracy. Alternatively, TX100 or RX200 may be controlled to perform the coupling state index measurement method in both the light load state and the load-connected state. Alternatively, TX100 or RX200 may be controlled to perform the coupling state index measurement method in each of three or more load states. By measuring the coupling state of RX200 in multiple load states and determining the coupling state based on these measurements, the coupling state can be determined with higher accuracy.

[0357] In addition to the coupling coefficient, there are several other quantities that can be used to represent the electromagnetic coupling state between the transmitting antenna and the receiving antenna. In this embodiment, these are collectively referred to as "coupling state indices." Each coupling state index has a value that corresponds to the electromagnetic coupling state between the transmitting antenna and the receiving antenna.

[0358] The contents of this embodiment can be similarly applied when using coupling state indicators other than coupling coefficients.

[0359] For example, one method for calculating the coupling state index is to use the transmission voltage V3 applied to the circuit (e.g., inverter) of the transmission unit 103 of TX100 and the receiving voltage V4 applied to the circuit (e.g., rectifier) ​​of the receiving unit 203 of RX200. Here, the transmission voltage V3 applied to the circuit of the transmission unit 103 of TX100 is, for example, the inverter input voltage input to the inverter of the transmission unit 103 of TX100, or the inverter output voltage output by the inverter. The receiving voltage V4 applied to the circuit of the receiving unit 203 of RX200 is, for example, the rectifier input voltage input to the rectifier of the receiving unit 203 of RX200. Using these, the coupling state index between the transmitting antenna and the receiving antenna can be calculated. Alternatively, the coupling state index between the transmitting antenna and the receiving antenna can be calculated using the transmission voltage V3 applied to the circuit (e.g., inverter) of the transmitting unit 103 of TX100 and the receiving voltage V5 of the circuit (e.g., rectifier) ​​of the receiving unit 203 of RX200. Here, the receiving voltage V5 applied to the circuit of the receiving unit 203 of RX200 is, for example, the rectifier output voltage output from the rectifier of the receiving unit 203 of RX200. Alternatively, the receiving voltage V5 applied to the circuit of the receiving unit 203 of RX200 is the voltage applied to the load (charging unit, battery). TX100 notifies RX200 of the transmission voltage V3, and RX200 can calculate the coupling state index using the notified V3 and V4 or V5. At this time, TX100 notifies RX200 of a constant calculated using the electrical characteristics of the power transmission antenna (e.g., L1), and RX200 can calculate the coupling state index using this constant.

[0360] Alternatively, RX200 notifies TX100 of the receiving voltage V4 or V5, and TX100 calculates the value of the coupling state index using the notified V4 or V5 and V3. At this time, RX200 also notifies TX100 of a constant calculated using the electrical characteristics of the receiving antenna (e.g., L2), and TX100 can calculate the coupling state index using this constant.

[0361] The TX100 and RX200 exchange information such as the voltage values ​​V1 to V5, the values ​​of the self-inductances L1 and L2, and / or constants representing the electrical characteristics of the transmitting and receiving antennas. The timing of voltage measurement and the timing of transmission and reception of each piece of information will be explained below.

[0362] The measurement of each voltage value is performed, for example, during the Ping phase. During the Ping phase, TX100 sends a Digital Ping to RX200. Therefore, any of the voltage values ​​V1, V2, V3, V4, and V5 that occur when the Digital Ping is sent can be used. During the Ping phase, TX100 or RX200 measures any of the values ​​from V1 to V5 and stores them in memory 106 or memory 208. Alternatively, TX100 sends a predetermined packet to RX200 to notify it of the timing for measuring the voltage value. Upon receiving the predetermined packet, RX200 measures any of the voltage values ​​V2, V4, and V5. RX200 measures any of the values ​​V2, V4, and V5 and stores them in memory 208. Alternatively, RX200 sends a predetermined packet to TX100 to notify it of the timing for measuring the voltage value. When TX100 receives the predetermined packet, it measures the voltage value of either V1 or V3. TX100 measures the value of either V1 or V3 and stores it in memory 106.

[0363] TX100 sends a predetermined transmission request packet to RX200 to request the transmission of a packet containing information on one or all of the voltage values ​​of V2, V4, and V5. Upon receiving the transmission request packet, RX200 sends a predetermined packet containing information on one or all of the voltage values ​​of V2, V4, and V5 to TX100. TX100 receives the predetermined packet containing information on one or all of the voltage values ​​of V2, V4, and V5 notified by RX200 and stores this information in memory 106. The information contained in the predetermined packet may include not only the voltage of RX200, but also the received power, the requested received power value, the value of the self-inductance L2, and constants calculated using the electrical characteristics of the receiving antenna. Additionally or alternatively, the information contained in the predetermined packet may include information on the temperature of RX200. TX100 receives this information from RX200 and can perform more appropriate control using this information and the calculated coupling state index. Information from RX200 can be notified to TX100 using a Signal Strength data packet as a predetermined packet. Alternatively, the predetermined packet may be an Identification data packet or an Extended Identification data packet in the Configuration phase. Alternatively, the predetermined packet may be a Configuration data packet. Alternatively, the predetermined packet may be a packet in the Calibration phase or Power Transfer phase. In other words, the predetermined packet may be RP1, RP2, or RP0. Note that this disclosure is not limited to the example using voltage values ​​generated when TX100 transmits Digital Ping. In the Selection phase, any of the voltage values ​​from V1 to V5 generated when TX100 transmits Analog Ping may be used. Alternatively, in the Power Transfer phase, any of the voltage values ​​from V1 to V5 generated when TX100 transmits power to RX200 may be used.

[0364] RX200 sends a predetermined transmission request packet to TX100 requesting the transmission of a packet containing information on one or all of the voltage values ​​of V1 and V3. Upon receiving the transmission request packet, TX100 sends a predetermined packet containing information on one or all of the voltage values ​​of V1 and V3 to RX200.

[0365] RX200 receives a predetermined packet containing information on one or all of the voltage values ​​V1 and V3 notified by TX100, and stores this information in memory 208. The information contained in the predetermined packet may include not only the voltage of TX100, but also information such as the transmission power value, the power value that can be transmitted, the value of the self-inductance L1, and constants calculated using the electrical characteristics of the transmission antenna. Additionally or alternatively, the information contained in the predetermined packet may include the foreign object detection results by the foreign object detection method described above (Power Loss method, Q value measurement method) and information regarding the temperature of TX100. RX200 receives this information from TX100 and can perform more appropriate control using this information and the calculated coupling state index. Furthermore, information from TX100 can be notified to RX200 using a Power Transmitter Capabilities (CAP) data packet as a predetermined packet. Alternatively, information from TX100 can be notified to RX200 using a Power Transmitter Identification (ID) data packet as a predetermined packet. This disclosure is not limited to the example using voltage values ​​generated when TX100 transmits Digital Ping. Any voltage value from V1 to V5 generated when TX100 transmits Analog Ping in the Selection phase may be used. Alternatively, any voltage value from V1 to V5 generated when TX100 transmits power to RX200 in the Power Transfer phase may be used.

[0366] When performing the coupling state index measurement method, the RX200 may be controlled to turn OFF the third switch unit 213 located between the resonant capacitor 211 and the power receiving unit 203, so that the terminals of the circuit composed of the power receiving antenna 205 and the resonant capacitor 211 are open. This prevents the coupling state index measurement method from being affected by the power receiving unit 203, the charging unit 206, and the battery 207, thus enabling more accurate measurement of the coupling state index.

[0367] Next, we will explain how to set threshold values ​​for state determination for the coupling state index obtained by the coupling state index measurement method. State determination includes determinations regarding the detection of foreign objects between the transmitting antenna and the receiving antenna, determinations regarding the detection of misalignment between the transmitting antenna and the receiving antenna, and determinations regarding the detection of separation between the transmitting antenna and the receiving antenna. For example, by performing the measurement method described above, it is possible to determine the presence or absence of a state abnormality using the state determination threshold values. The first to fourth threshold setting methods will be explained below.

[0368] The first threshold setting method involves setting the value of the coupling state index used for detecting the state between the transmitting antenna and the receiving antenna as the threshold value when there are no abnormalities in the coupling state index. In state detection, for example, judgment results such as "abnormal state present," "high probability of abnormal state," "low probability of abnormal state," and "no abnormal state" can be obtained. Assume that the RX200 is mounted on the test TX100 and there are no abnormalities in the coupling state between the transmitting antenna and the receiving antenna. In this case, the value of the coupling state index between the test TX100 including the transmitting antenna and the RX200 including the receiving antenna can be used as the threshold. The value of the coupling state index (threshold) measured in advance is stored in memory 208 by the RX200, and the RX200 notifies the TX100 of the threshold. The TX100 performs judgment processing related to state detection using the threshold. This threshold may be transmitted by the RX200 to the TX100 in the FOD Status data pack specified in the WPC standard. Alternatively, the value of the coupling state index between the transmitting and receiving antennas that allows a predetermined power transmission efficiency to be obtained may be set as the threshold. In state detection, for example, the following determination results may be obtained: - "The predetermined power transmission efficiency cannot be obtained" or "The coupling between the transmitting and receiving antennas is weak." - "There is a high possibility that the predetermined power transmission efficiency cannot be obtained" or "There is a possibility that the coupling between the transmitting and receiving antennas is weak." - "There is a high possibility that the predetermined power transmission efficiency can be obtained" or "There is a possibility that the coupling state between the transmitting and receiving antennas is good." - "The predetermined power transmission efficiency can be obtained" or "The coupling state between the transmitting and receiving antennas is good."

[0369] Here, we assume that RX200 is mounted on the test TX100, there are no abnormal conditions between the transmitting antenna and the receiving antenna, and a predetermined power transmission efficiency is obtained. In this case, the value of the coupling state index between the test TX100 including the transmitting antenna and RX200 including the receiving antenna can be used as a threshold. RX200 stores the value of the coupling state index measured in advance as a threshold in memory 208 and notifies TX100 of the threshold. TX100 performs a determination process related to state detection using this threshold. This threshold may be transmitted by RX200 to TX100 in the FOD Status data package specified in the WPC standard.

[0370] The second threshold setting method is a method in which, under predetermined conditions, TX100 and RX200 set a coupling state index measured by, for example, the measurement method described above as the threshold. The predetermined condition is "a state in which there are no abnormal conditions between the transmitting antenna and the receiving antenna." In the method for confirming this state, foreign object detection using the Power Loss method, foreign object detection using the waveform attenuation method, foreign object detection using the Q value measurement method, or foreign object detection based on the temperature of TX100 or RX200 can be used. If, as a result, it is determined that there are no abnormal conditions, it can be confirmed with a high probability that "there are no abnormal conditions between the transmitting antenna and the receiving antenna."

[0371] In other words, this verification is performed by methods and means other than the coupling state index measurement method. If the result is determined to be "no abnormalities" (or "no foreign matter"), the coupling state index is measured using, for example, the measurement method described above, and an appropriate threshold is set based on the measurement results.

[0372] For example, in the WPC standard, foreign object detection processing using the Q-value measurement method is performed during the Negotiation or Renegotiation phase. If the foreign object detection processing determines "no abnormalities" (or "no foreign objects"), the coupling state index is measured using the coupling state index measurement method in the Negotiation or Renegotiation phase or later. Based on the measurement results, it is possible to set a more appropriate threshold. In addition, foreign object detection processing using the Power Loss method is performed during the Power Transfer phase. After the execution of this foreign object detection processing, the coupling state index is measured using, for example, the measurement method described above, and based on the measurement results, it is possible to set a more appropriate threshold. Alternatively, foreign object detection processing can be performed in the Selection or Ping phase using Quality Factor, etc. In this case, the coupling state index is measured using the coupling state index measurement method after the foreign object detection process is performed, and an appropriate threshold can be set based on the measurement results.

[0373] Next, the third threshold setting method will be explained with reference to Figure 28. Figure 28 is a diagram illustrating the threshold setting method in state detection using a coupling state index. In Figure 28, the horizontal axis represents the power transmission value, and the vertical axis represents the coupling state index. On the graph line shown by the straight line segment 1202, point 1200 corresponds to the power transmission value Pt1 and the coupling state index value k1, and point 1201 corresponds to the power transmission value Pt2 and the coupling state index value k2. On the same graph line, point 1203 corresponds to the power transmission value Pt3 and the coupling state index value k3. The coupling state index measurement method described above can be used to calculate each coupling state index value.

[0374] As shown in Figure 3, the charging unit 206 and the battery 207 are connected as loads to the power receiving unit 203 of the RX200, so the calculated coupling state index value changes depending on the load state. In order to determine whether or not there is a state abnormality depending on the load state, it is necessary to set a threshold value for the coupling state index.

[0375] First, when power is transmitted from TX100, RX200 controls the load to be in a light load state. A light load state is a state in which no power is supplied to the load of RX200, or only power below a threshold is supplied. Alternatively, a light load state is a load state in which the power value received by RX200 falls within a predetermined range (hereinafter referred to as the "first range").

[0376] Let Pt1 be the transmission power value of TX100 in this state. Then, RX200 sends a packet to TX100 indicating a request to perform a coupling state index measurement. Alternatively, TX100 sends a packet to RX200 indicating a request to perform a coupling state index measurement. TX100 and RX200 each perform measurements of the transmission voltage on the TX100 side and the receiving voltage on the RX200 side in that state. TX100 and RX200 exchange information such as the values ​​of V1 to V5, the self-inductance values ​​L1 and L2, and constants calculated using the electrical characteristics of the transmitting and receiving antennas. Then, TX100 or RX200 calculates the coupling state index value k1 using this information. When RX200 has calculated the coupling state index value k1, RX200 notifies TX100 of the result. When TX100 calculates the coupling state index value k1, TX100 notifies RX200 of the result and Pt1. At this time, TX100 recognizes the transmitted power value Pt1 and stores CP1200, which associates Pt1 and k1, in memory 106. RX200 also stores CP1200, which associates Pt1 and k1, in memory 208.

[0377] Next, when power is transmitted from TX100, RX200 controls the load to enter a load-connected state. The load-connected state is a state in which the load of RX200 is supplied with the maximum power, or power equal to or greater than a threshold. Here, "maximum power" refers to power close to the Reference Power value. Alternatively, the load-connected state is a load state in which the power value received by RX200 falls within a predetermined range (hereinafter referred to as the "second range"). Here, the second range is a range of power values ​​higher than the first range.

[0378] Let Pt2 be the transmission power value of TX100 in this state. Then, RX200 sends a packet to TX100 indicating a request to perform a coupling state index measurement. Alternatively, TX100 sends a packet to RX200 indicating a request to perform a coupling state index measurement. TX100 and RX200 each perform measurements of the transmission voltage on the TX100 side and the receiving voltage on the RX200 side in that state. TX100 and RX200 exchange information such as the values ​​of V1 to V5, the values ​​of self-inductance L1 and L2, and constants calculated using the electrical characteristics of the transmitting and receiving antennas. Then, TX100 or RX200 calculates the coupling state index value k2 using this information. When RX200 has calculated the coupling state index value k2, RX200 notifies TX100 of the result. When TX100 calculates the coupling state index value k2, TX100 notifies RX200 of the result and Pt2. TX100 stores CP1201, which associates Pt2 and k2, in memory 106. RX200 also stores CP1201, which associates Pt2 and k2, in memory 208.

[0379] Next, TX100 performs linear interpolation between CP1200 and CP1201 to generate line segment 1202. Line segment 1202 shows the relationship between transmitted power and the coupling state index when there are no abnormalities around TX100 and RX200. Using line segment 1202, TX100 can estimate the coupling state index value for each transmitted power value when there are no abnormalities around TX100 and RX200. For example, let's assume the transmitted power value is Pt3. In this case, the coupling state index value k3 can be estimated from point 1203 on line segment 1202 corresponding to the transmitted power value Pt3. Based on the estimation result, TX100 can calculate a threshold value used to determine the presence or absence of abnormalities for each transmitted power value. For example, a coupling state index value obtained by adding a predetermined value (a value corresponding to the measurement error) to the estimated result of the coupling state index value when there are no abnormalities at a certain transmitted power value can be set as the threshold value for determination.

[0380] Thus, the calibration process (abbreviated as CAL process) performed by TX100 and RX200 to obtain a combination of transmission power value and coupling state index value is called the "CAL process of the coupling state index measurement method." Furthermore, performing the calibration process again after the initial calibration process to update or add calibration points is called the recalibration process, abbreviated as ReCAL process. Note that RX200 may perform the control to bring the load into a light load state and the control to bring the load into a connected state after notifying TX100 of the control. Also, either of these two controls may be performed first.

[0381] The fourth threshold setting method is a method in which TX100 or RX200 pre-sets a threshold for a coupling state index having a value within a predetermined range. This threshold is a predetermined value that is a common value independent of the RX200 being transmitted to, and is maintained by TX100 or RX200. The threshold may be a fixed value that does not depend on the situation, or it may be a variable value determined by TX100 or RX200 depending on the situation. For example, if the coupling state index is the coupling coefficient k, the range of the k value is "0 ≤ k ≤ 1". For example, TX100 or RX200 judges (determines) that there is a "state abnormality" when "0 ≤ k < 0.2", and judges that there is a "high possibility of a state abnormality" when "0.2 ≤ k < 0.5". TX100 or RX200 judges that there is a "low possibility of a state abnormality" when "0.5 ≤ k < 0.8", and judges that there is "no state abnormality" when "0.8 ≤ k ≤ 1". The data for the conditions related to the k value is stored in memory beforehand, and a decision (judgment) process is executed based on this data.

[0382] Alternatively, the TX100 or RX200 may determine, for example, that "the predetermined power transmission efficiency cannot be obtained" or "the coupling between the transmitting and receiving antennas is weak" if "0 ≤ k < 0.2". The TX100 or RX200 may determine that "the predetermined power transmission efficiency is likely to be not obtained" or "the coupling between the transmitting and receiving antennas is likely to be weak" if "0.2 ≤ k < 0.5". The TX100 or RX200 may determine that "the predetermined power transmission efficiency is likely to be obtained" or "the coupling between the transmitting and receiving antennas is likely to be good" if "0.5 ≤ k < 0.8". The TX100 or RX200 may determine that "the predetermined power transmission efficiency can be obtained" or "the coupling between the transmitting and receiving antennas is good" if "0.8 ≤ k ≤ 1". The condition data for the k value is stored in memory beforehand, and the determination process is executed based on this data.

[0383] Furthermore, in setting a threshold value for determination related to state detection using a coupling state index, a predetermined value (a value corresponding to the measurement error) can be added to the coupling state index value calculated based on the measurement result or received information to set the determination threshold value. Note that this disclosure is not limited to the use of a single threshold value, but allows for the setting of multiple threshold values ​​in stages.

[0384] Next, the timing for calculating the coupling state between the transmitting antenna and the receiving antenna using the coupling state index measurement method will be explained. The calculation (measurement) of the coupling state is performed when RX200 transmits a predetermined packet to TX100. Here, the predetermined packet is the Signal Strength data packet transmitted by RX200 to TX100. Alternatively, the predetermined packet may be the Identification data packet or Extended Identification data packet in the Configuration phase. Alternatively, the predetermined packet may be the Configuration data packet. Alternatively, the predetermined packet may be a packet in the Calibration phase or Power Transfer phase. In other words, the predetermined packet may be RP1, RP2, or RP0.

[0385] When TX100 receives a predetermined packet from RX200, it calculates a coupling state index between the transmitting and receiving antennas. Then, TX100 makes a determination by comparing the calculated coupling state index with a determination threshold set by the method described above. If TX100 determines that there is "no abnormality," it sends an affirmative response ACK or status information indicating "no abnormality" to RX200. If TX100 determines that there is "a low probability of an abnormality" or "a high probability of an abnormality," it sends status information indicating the respective determination result to RX200. If TX100 determines that there is an "abnormality," it sends a negative response NAK or status information indicating "an abnormality" to RX200.

[0386] Alternatively, if TX100 determines that "a predetermined power transmission efficiency can be obtained" or "the coupling state between the transmitting antenna and the receiving antenna is good," it transmits an affirmative response ACK or status information indicating the determination result to RX200. If TX100 determines that "the predetermined power transmission efficiency can be obtained" or "the coupling state between the transmitting antenna and the receiving antenna is good," it transmits status information indicating the determination result to RX200. If TX100 determines that "the predetermined power transmission efficiency cannot be obtained" or "the coupling between the transmitting antenna and the receiving antenna is weak," it transmits a negative response NAK or status information indicating the determination result to RX200.

[0387] State information refers to numerical information corresponding to the state, as follows: • State information "0" corresponds to the judgment result of "No state abnormality", "The predetermined power transmission efficiency is obtained", or "The coupling state between the transmitting antenna and the receiving antenna is good". • State information "1" corresponds to the judgment result of "Low possibility of state abnormality", "High possibility of obtaining the predetermined power transmission efficiency", or "Possibility that the coupling state between the transmitting antenna and the receiving antenna is good". • State information "2" corresponds to the judgment result of "High possibility of state abnormality", "High possibility of not obtaining the predetermined power transmission efficiency", or "Possibility that the coupling between the transmitting antenna and the receiving antenna is weak". • State information "3" corresponds to the judgment result of "State abnormality present", "Predetermined power transmission efficiency is not obtained", or "Weak coupling between the transmitting antenna and the receiving antenna".

[0388] Alternatively, the calculation (measurement) of the coupling state is performed by TX100 sending a predetermined packet to RX200. Here, the predetermined packet is the Power Transmitter Capabilities (CAP) data packet that TX100 sends to RX200. Alternatively, the predetermined packet is the Power Transmitter Identification (ID) data packet.

[0389] When RX200 receives a predetermined packet from TX100, it calculates a coupling status index between the transmitting and receiving antennas. Then, RX200 makes a determination by comparing the calculated coupling status index with a determination threshold set by the method described above. If RX200 determines that there is "no abnormality," it sends a predetermined packet containing status information indicating that determination result to TX100. If RX200 determines that there is "a low probability of an abnormality" or "a high probability of an abnormality," it sends a predetermined packet containing status information indicating the respective determination result to TX100. If RX200 determines that there is an "abnormality," it sends a predetermined packet containing status information indicating that determination result to TX100.

[0390] Alternatively, if RX200 determines that "a predetermined power transmission efficiency can be obtained" or "the coupling state between the transmitting antenna and the receiving antenna is good," it transmits status information indicating the determination result to TX100. If RX200 determines that "the predetermined power transmission efficiency can be obtained" or "the coupling state between the transmitting antenna and the receiving antenna is good," it transmits status information indicating the determination result to TX100. If RX200 determines that "the predetermined power transmission efficiency cannot be obtained" or "the coupling between the transmitting antenna and the receiving antenna is weak," it transmits status information indicating the determination result to TX100.

[0391] State information refers to numerical information corresponding to the state, as follows: • State information "0" corresponds to the judgment result of "No state abnormality", "The predetermined power transmission efficiency is obtained", or "The coupling state between the transmitting antenna and the receiving antenna is good". • State information "1" corresponds to the judgment result of "Low possibility of state abnormality", "High possibility of obtaining the predetermined power transmission efficiency", or "Possibility that the coupling state between the transmitting antenna and the receiving antenna is good". • State information "2" corresponds to the judgment result of "High possibility of state abnormality", "High possibility of not obtaining the predetermined power transmission efficiency", or "Possibility that the coupling between the transmitting antenna and the receiving antenna is weak". • State information "3" corresponds to the judgment result of "State abnormality present", "Predetermined power transmission efficiency is not obtained", or "Weak coupling between the transmitting antenna and the receiving antenna".

[0392] Next, we will explain how the TX100 operates to properly and rapidly charge the RX200's battery. To rapidly charge, the TX100 needs to transmit power to the RX200 at a higher power level. The WPC standard has two modes: BPP, which transmits 5 watts or less of power to the RX200, and EPP, which transmits 15 watts or less of power. BPP uses the Baseline Protocol, a unidirectional communication protocol. EPP uses the Extended Protocol, an extended protocol for bidirectional communication. In this embodiment, we assume a case where higher power transmission than EPP is performed. That is, we assume a case where the TX100 transmits more than 15 watts of power to the RX200. This state (profile, mode) of transmitting more than 15 watts of wireless power to the RX200 is called the rapid charging mode, rapid charging profile, or rapid charging power profile. Alternatively, the state in which the TX100 and RX200 can set a GP of more than 15 watts (Profile, mode) is called the rapid charging mode, rapid charging profile, or rapid charging power profile. Furthermore, the maximum value of the GP that can be set in the rapid charging mode, rapid charging profile, or rapid charging power profile shall be 50 watts. Here, a power profile is a set of functions that defines the conformance level of the power transmission or receiving device.

[0393] The following describes the operation of TX100 and RX200 when wireless charging is performed in rapid charging mode, using the flowcharts showing an example of the power transmission device processing shown in Figure 29 and the flowchart showing an example of the power receiving device processing shown in Figure 30. The following description will focus on the Negotiation phase and subsequent phases after TX100 and RX200 have executed the Selection, Ping, and Configuration phases described above (not shown).

[0394] First, in the Negotiation phase, the RX200 requests the transmission of information indicating whether the power transmission device supports the rapid charging mode (F3001). Specifically, the request is made using the General Request (GRQ) data package specified in the WPC standard.

[0395] When TX100 receives a request from RX200 to transmit information indicating whether the power transmission device supports fast charging mode (F2901), it transmits a packet to RX200 containing information indicating that it supports fast charging mode (F2902). Here, "supporting fast charging mode" means that TX100 or RX200 has hardware, control means, and functions capable of operating in fast charging mode. This packet is a Power Transmitter Capabilities (CAP) data packet. Alternatively, this packet is a Power Transmitter Identification (ID) data packet. These packets have a 1-bit field indicating whether or not they support fast charging mode. When the TX100 notifies the RX200 that it supports fast charging mode, it stores "1" in the corresponding field. When it notifies the RX200 that it does not support fast charging mode, it stores "0" in the corresponding field. Note that the meanings of "1" and "0" stored in the corresponding field may be reversed.

[0396] Alternatively, the Power Transmitter Identification (ID) data package contains fields for storing WPC standard version information. The fields for storing the major and minor versions of the Power Transmitter ID data package contain information that allows for the identification of the WPC standard (Qi standard) supported by the TX100.

[0397] These fields are used to store information about versions that support MPP, and information about versions that support both MPP and fast charging mode. If TX100 does not support MPP, it is controlled not to notify RX200 of the information indicating that it supports the fast charging mode described above. In other words, in the above example, if TX100 does not support MPP, TX100 is controlled not to send RX200 the version information that supports both MPP and fast charging mode. For example, TX100 may send RX200 the version information that does not support either MPP or fast charging mode. Also, in order for TX100 to notify RX200 of the information indicating that it supports the fast charging mode described above, it must support MPP. In other words, in the above example, if TX100 supports fast charging mode, TX100 is controlled to send RX200 the version information that supports both MPP and fast charging mode.

[0398] The RX200 determines whether it has received a packet from the TX100 containing information indicating that it supports the rapid charging mode (F3002). If it does not receive a packet, the RX200 periodically or irregularly performs the F3002 determination until a predetermined time has elapsed (No in F3002, No in F3017). If the RX200 does not receive a packet containing information indicating that the TX100 supports the rapid charging mode within the predetermined time (No in F3002, Yes in F3017), it terminates processing. In other words, the RX200 returns to the Selection phase.

[0399] When RX200 receives a packet from TX100 containing information indicating that it supports fast charging mode (F3002: Yes), it sends a packet to TX100 containing information indicating that it supports fast charging mode (F3003). This packet is, for example, an FOD Status data packet. This packet has a 1-bit field indicating whether or not it supports fast charging mode. If RX200 notifies TX100 that it supports fast charging mode, it stores "1" in this field, and if RX200 notifies TX100 that it does not support fast charging mode, it stores "0" in this field. In this case, since RX200 is a power receiving device that supports fast charging mode, it sends a packet containing information indicating that it supports fast charging mode. Note that the meanings of "1" and "0" stored in the relevant field may be reversed. Furthermore, if the packet is used in the Negotiation phase, a different packet may be used instead of the FOD Status data packet.

[0400] TX100 determines whether it has received a packet from RX200 containing information indicating that it supports rapid charging mode (F2903). If it does not receive a packet, TX100 periodically or irregularly performs the F2903 determination until a predetermined time has elapsed (No in F2903, No in F2918). If TX100 does not receive a packet containing information indicating that RX200 supports rapid charging mode within the predetermined time (No in F2903, Yes in F2918), it terminates processing. In other words, TX100 returns to the Selection phase.

[0401] The above example shows that after RX200 receives information from TX100 that "TX100 supports fast charging mode," RX200 transmits information to TX100 indicating that "RX200 supports fast charging mode." However, the order of sending and receiving information may be reversed. That is, TX100 may receive information from RX200 that "RX200 supports fast charging mode," and then transmit information to RX200 indicating that "TX100 supports fast charging mode." For example, the information indicating that "RX200 supports fast charging mode" may be transmitted before the Configuration phase. This information may be stored in the Signal Strength data package transmitted from RX200 to TX100 during the Ping phase. Alternatively, the information may be stored in a packet transmitted during the Configuration phase. This packet can be an Identification data packet, an Extended Identification data packet, or a Configuration data packet.

[0402] Furthermore, the Identification data package contains fields for storing WPC standard version information. The fields for storing the major and minor versions of the Identification (ID) data package contain information that allows for the identification of the WPC standard (Qi standard) version supported by the RX200. These fields are used to store information about versions that support MPP, and versions that support both MPP and fast charging mode. If the RX200 does not support MPP, it is controlled not to notify the TX100 of the information indicating that it supports the fast charging mode mentioned above. In other words, in the example above, if the RX200 "does not support MPP", the RX200 is controlled not to send "version information that supports both MPP and fast charging mode" to the TX100.

[0403] For example, the RX200 may send version information to the TX100 indicating that it does not support either MPP or fast charging mode. Also, if the RX200 notifies the TX100 that it supports the fast charging mode as described above, the RX200 must support MPP. In other words, in the above example, if the RX200 supports fast charging mode, the RX200 is controlled to send version information to the TX100 that supports both MPP and fast charging mode.

[0404] Alternatively, either the TX100 or the RX200 may send a packet containing information indicating that it supports "fast charging mode" to either the RX200 or the TX100.

[0405] Next, the RX200 transmits a packet to the TX100 containing "information for determining whether the conditions for transitioning to rapid charging mode are met" (F3004). This packet can be an FOD Status data packet. The FOD Status data packets transmitted in F3003 and F3004 may be the same single packet, or they may be different FOD Status data packets. In the former case, F3003 and F3004 are performed in a single process. In addition, any packet used in the Negotiation phase may be used instead of the FOD Status data packet. Furthermore, the packet containing "information for determining whether or not the conditions for switching to rapid charging mode are met" and the packet containing "information that the TX100 supports rapid charging mode" may be of the same type or of different types.

[0406] Here, we will explain the conditions under which the device can switch to fast charging mode. These conditions may include all of the following conditions, a combination of some of them, or just one of them.

[0407] [First Condition] The first condition is that the TX100 and RX200 are compatible with MPP. MPP is adopted in "Qi2", the next-generation standard of the wireless power receiving standard "Qi". MPP has the function of fixing the TX100 and RX200 in predetermined positions with high precision. Multiple means can be considered for fixing the TX100 and RX200 in predetermined positions with high precision. For example, the transmitting antenna (transmitting coil) of the TX100 and the receiving antenna (receiving coil) of the RX200 can be precisely opposed (facing each other) by using the magnets built into the TX100 and RX200, respectively. In other words, in this case, MPP can be said to be an extended function of BPP, a profile (power profile) that uses magnets to align the power transmitting device and the power receiving device. The magnets may be permanent magnets or electromagnets. When transmitting large amounts of power in rapid charging mode, increasing power transmission efficiency and reducing power loss is desirable for the environment. Therefore, if both TX100 and RX200 are MPP compatible and capable of operating in MPP mode, they are controlled to operate in rapid charging mode. For this reason, in F3004, RX200 sends a packet to TX100 containing information indicating that "RX200 is capable of MPP." If RX200 is not capable of operating in MPP mode, it will send a packet containing information indicating that it is not MPP compatible. In other words, in F3004, RX200 sends a packet containing information indicating whether it is possible to align the power transmission device and the power reception device using magnets.

[0408] [Second Condition] The second condition is that TX100 and RX200 have a predetermined method (means) for fixing TX100 and RX200 to a predetermined position with high precision.

[0409] Alternatively, the TX100 and RX200 have a predetermined method (means) for precisely fixing the transmitting antenna of the TX100 and the receiving antenna of the RX200 in predetermined positions. Several methods can be cited as a method for precisely fixing the TX100 and RX200 in predetermined positions, or a method for precisely fixing the transmitting antenna of the TX100 and the receiving antenna of the RX200 in predetermined positions (alignment method).

[0410] (First alignment method) A method in which the TX100 and RX200 each have built-in magnets, and the transmitting antenna of the TX100 and the receiving antenna of the RX200 are brought into opposition by magnetic force.

[0411] (Second alignment method) A method in which the TX100 has a movable transmitting antenna, and the transmitting antenna is moved near the receiving coil of the RX200 so that the transmitting antenna of the TX100 and the receiving antenna of the RX200 face each other.

[0412] (Third alignment method) A method in which the TX100 has a holder for fixing the RX200 so that the RX200 can be positioned at a predetermined position on the TX100, and the transmitting antenna of the TX100 and the receiving antenna of the RX200 are positioned opposite each other by arranging the RX200 along the holder.

[0413] Depending on the alignment method, the positional accuracy of the opposing positions of the TX100's transmitting antenna and the RX200's receiving antenna will differ. As mentioned above, the higher the positional accuracy of the opposing positions of the TX100's transmitting antenna and the RX200's receiving antenna, the higher the power transmission efficiency, which is desirable. Therefore, when the TX100 and RX200 support a predetermined alignment method that allows the TX100's transmitting antenna and the RX200's receiving antenna to be aligned with a predetermined or higher accuracy, the TX100 and RX200 are controlled to operate in rapid charging mode.

[0414] For example, among the alignment methods described above, the first alignment method is an alignment method that can align the transmitting antenna of TX100 and the receiving antenna of RX200 with a predetermined or higher level of precision. The transmitting antenna (transmitting coil) of TX100 and the receiving antenna (receiving coil) of RX200 can be precisely opposed (facing each other) by using the magnets built into TX100 and RX200, respectively. Therefore, when TX100 and RX200 are compatible with the first alignment method, TX100 and RX200 are controlled to operate in rapid charging mode. In F3004, RX200 transmits a packet to TX100 containing information indicating that "RX200 is compatible with the first alignment method." For example, the following can be used as a method for notifying information regarding the alignment method.

[0415] (1) A method by which RX200 notifies the corresponding alignment method by representing it with predetermined information. For example, if RX200 supports the first alignment method, RX200 includes the information "1" in a predetermined packet and transmits it to TX100. If RX200 supports the second alignment method, RX200 includes the information "2" in a predetermined packet and transmits it to TX100. If RX200 supports the third alignment method, RX200 includes the information "3" in a predetermined packet and transmits it to TX100.

[0416] (2) A method of notifying whether RX200 supports the first alignment method by representing it with predetermined information. For example, if RX200 supports the first alignment method, RX200 includes the information "1" in a predetermined packet and transmits it to TX100. If RX200 does not support the first alignment method, RX200 includes the information "2" in a predetermined packet and transmits it to TX100.

[0417] [Third Condition] The third condition is that the coupling state index between the transmitting antenna of TX100 and the receiving antenna of RX200 is equal to or exceeds a predetermined value. The method for measuring the coupling state index between the transmitting antenna of TX100 and the receiving antenna of RX200, and the method for setting thresholds for determining the superiority or inferiority of the coupling state index, are as described above.

[0418] If the transmitting antenna of TX100 and the receiving antenna of RX200 are facing each other, the coupling state index value will also be a good value (a large value in the case of the coupling coefficient), resulting in higher power transmission efficiency, which is desirable. Therefore, if the measured coupling state index between TX100 and RX200 is equal to or exceeds a set threshold, TX100 and RX200 are controlled to operate in rapid charging mode.

[0419] In F3004, RX200 transmits a packet to TX100 containing "information that TX100 uses to calculate the coupling state index between the transmitting antenna and the receiving antenna." The information that TX100 receives from RX to calculate the coupling state index between the transmitting antenna and the receiving antenna is as described above in the explanation of the coupling state index measurement method.

[0420] In the above explanation, the method for determining the coupling state index between the TX100 transmitting antenna and the RX200 receiving antenna was described based on the measurement method of the coupling state index between the TX100 transmitting antenna and the RX200 receiving antenna, and the method for setting the threshold value of the coupling state index. Below, we will describe another method for determining the coupling state index between the TX100 transmitting antenna and the RX200 receiving antenna.

[0421] <Another method for determining the coupling state index between the transmitting antenna of TX100 and the receiving antenna of RX200> RX200 measures the received power value and notifies TX100 of the measurement result. For example, in the Ping phase, TX100 transmits a Digital Ping (DP), and RX200 measures the voltage value of the received DP. RX200 stores the measured voltage value as the Signal Strength Value in the Signal Strength data packet. RX200 transmits this packet to TX100, and TX100 receives this packet from RX200. The Signal Strength Value is the value measured by RX200 as a voltage value with respect to the power transmitted by TX100. In other words, the magnitude of the received voltage value (measured value) represents the strength of the coupling between the transmitting antenna and the receiving antenna. TX100 compares the Signal Strength Value in the packet with a threshold value. TX100 determines that a strong coupling state exists if the Signal Strength Value is greater than or equal to the threshold value, and that a weak coupling state exists if the Signal Strength Value is less than the threshold value. The Signal Strength Value is the value measured by RX200 as a voltage value from the power transmitted by TX100. RX200 determines the strength of the coupling between the transmitting antenna and the receiving antenna based on the comparison result between the measured Signal Strength Value and the threshold value. The RX200 determines that a strong coupling state is in effect if the Signal Strength Value is above a threshold, and that a weak coupling state is in effect if the Signal Strength Value is below the threshold. The TX100 or RX200 is controlled to operate in rapid charging mode when the transmitting antenna and receiving antenna are in a strongly coupled state. On the other hand, the TX100 or RX200 is controlled not to operate in rapid charging mode when the transmitting antenna and receiving antenna are in a weakly coupled state.

[0422] Regarding the threshold setting in the "alternative method for determining the coupling state index between the transmitting antenna of TX100 and the receiving antenna of RX200" described above, the following may be used: In other words, TX100 may pre-store a threshold by executing the first or fourth threshold setting method among the threshold setting methods for measuring the coupling state index. Alternatively, RX200 may notify TX100 of the threshold. Or, TX100 and RX200 may pre-store the same threshold.

[0423] [Fourth Condition] The fourth condition is that no foreign matter is detected in the foreign matter detection method described above, or the probability of the presence of a foreign matter obtained in the foreign matter detection method described above is less than or equal to a predetermined value. The foreign matter detection method is the Power Loss method and / or the Q-value measurement method.

[0424] If foreign objects are present near the transmitting antenna of the TX100 and the receiving antenna of the RX200, wireless power transmission is undesirable because heat will be generated in the foreign objects. This is especially undesirable as the amount of heat generated may increase as the power transmitted from the TX100 to the RX200 increases. Therefore, the foreign object detection method controls the TX100 and RX200 to operate in rapid charging mode if no foreign objects are present or if the probability of foreign objects being present is below a predetermined value.

[0425] In F3004, RX200 transmits a packet to TX100 containing "information that TX100 uses to perform the foreign object detection method." The information that TX100 receives from RX200 is all the information that RX200 should provide to TX100 in order for TX100 to perform the various foreign object detection methods described above. This information also includes information used to determine the thresholds to be set when performing the foreign object detection method.

[0426] When determining whether to shift to the rapid charging mode, it is determined based on the probability of the presence of foreign matter as the fourth condition. However, the threshold value of the probability of detecting the presence of foreign matter for this determination may be a dedicated threshold value for determining whether to shift to the rapid charging mode. That is, the threshold value of the foreign matter detection method executed when operating in the EPP that performs power transmission of 15 watts or less and the threshold value for determining the shift to the rapid charging mode are set differently. For example, the threshold value for determining the shift to the rapid charging mode is set to a stricter value than the threshold value of the foreign matter detection method executed when operating in the EPP that performs power transmission of 15 watts or less. The threshold value is set by adding a predetermined margin to the reference value. However, the threshold value for determining the shift to the rapid charging mode is set with a smaller margin with respect to the threshold value of the foreign matter detection method executed when operating in the EPP that performs power transmission of 15 watts or less. As a result, it becomes possible to safely shift to the high-power power transmission in the rapid charging mode.

[0427] [Fifth condition] The fifth condition is the case where the temperature at a predetermined location of TX100 or RX200 is at or below a predetermined value or less than a predetermined value. When performing high-power power transmission in the rapid charging mode, accordingly, components of TX100 or RX200 (power transmission antenna, power reception antenna, battery, etc.) generate more heat than in the case of low-power power transmission. Therefore, if the temperature of TX100 or RX200 is high and the device shifts to the rapid charging mode and performs high-power power transmission, there is also a risk of leading to the destruction of TX100 or RX200. Therefore, when the temperature of TX100 or RX200 is at or below a predetermined value or less than a predetermined value, TX100 and RX200 are controlled to operate in the rapid charging mode.

[0428] Here, a method of controlling based on the temperature of TX100 will be described. Assume that TX100 and RX200 each have temperature sensors at a plurality of locations. In particular, temperature sensors are arranged at a higher density in the power transmission antenna 105, the charging stand 300, and the power reception antenna 205 than in other locations.

[0429] In F3004, RX200 transmits a packet including "timing information indicating the timing at which TX100 acquires temperature information of the temperature sensor of TX100" to TX100. The information may include information used to determine the threshold value of the set temperature.

[0430] [Sixth condition] The sixth condition is the case where TX100 and RX200 are operating in the above-described MPP. TX100 and RX200 perform predetermined control and operate in MPP. Then, when TX100 and RX200 are operating in MPP, it is determined that "the conditions for enabling transition to the rapid charging mode are satisfied".

[0431] As described above, the first to sixth conditions have been described as "conditions for enabling transition to the rapid charging mode". Note that the "conditions for enabling transition to the rapid charging mode" may be the first to sixth conditions described above combined as the "conditions for enabling transition to the rapid charging mode". For example, the case where both the first condition and the second condition described above are satisfied may be regarded as the "conditions for enabling transition to the rapid charging mode". Also, not only two of the first to sixth conditions may be combined, but three or four or five or all of them may be combined and regarded as the "conditions for enabling transition to the rapid charging mode".

[0432] Next, TX100 determines whether it has received a packet including "information for determining whether the conditions for enabling transition to the rapid charging mode are satisfied" from RX200 (F2904).

[0433] If the packet is not received, TX100 periodically or irregularly performs the determination of F2904 until a predetermined time elapses (No in F2904, No in F2919). If the packet including "information for determining whether the conditions for enabling transition to the rapid charging mode are satisfied" is not received even after the predetermined time has elapsed (No in F2904, Yes in F2919), TX100 ends the process. That is, TX100 transitions to the Selection phase.

[0434] When the TX100 receives a packet containing "information for determining whether the conditions for transitioning to rapid charging mode are met" (F2904: Yes), it makes a determination based on that information (F2905) as to whether the conditions for transitioning to rapid charging mode are met. If the determination is made that "the conditions for transitioning to rapid charging mode are met" (F2905: Yes), the TX100 proceeds to F2906. If the determination is made that "the conditions for transitioning to rapid charging mode are not met" (F2905: No), the TX100 proceeds to F2915.

[0435] Here, we will explain the process for determining each of the conditions mentioned above.

[0436] [When the first condition is met as a condition for transitioning to rapid charging mode] If TX100 receives a packet containing information indicating that "RX200 is capable of supporting MPP" and TX100 is also capable of supporting MPP, it determines that the conditions for transitioning to rapid charging mode are met and proceeds to F2906. However, if TX100 receives a packet that does not contain information indicating that "RX200 is capable of supporting MPP", it determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915. Alternatively, if TX100 receives a packet containing information indicating that "RX200 is not capable of supporting MPP", it determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915. In other words, TX100 controls the device to operate in rapid charging mode only when both TX100 and RX200 are capable of supporting MPP. On the other hand, the TX100 is controlled not to operate in rapid charging mode if at least one of the TX100 and RX200 is not compatible with MPP.

[0437] [When the second condition is included as a condition for transitioning to rapid charging mode] If TX100 receives a packet containing information indicating that "RX200 supports the first alignment method" and TX100 also supports the first alignment method, it determines that the conditions for transitioning to rapid charging mode are met. In other words, in this case, TX100 proceeds to F2906. On the other hand, if TX100 receives a packet that does not contain information indicating that "RX200 supports the first alignment method", it determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915. Alternatively, if TX100 receives a packet containing information indicating that "RX200 does not support the first alignment method", it determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915. In short, TX100 controls both TX100 and RX200 to operate in rapid charging mode only when both support the first alignment method.

[0438] On the other hand, the TX100 is controlled not to operate in rapid charging mode if at least one of the TX100 and RX200 does not support the first alignment method.

[0439] [When the third condition is included as a condition for transitioning to rapid charging mode] TX100 calculates the coupling state index using "information used by TX100 to calculate the coupling state index between the transmitting antenna and the receiving antenna". If the coupling state index satisfies predetermined conditions, TX100 determines that the conditions for transitioning to rapid charging mode are met and proceeds to F2906. Here, "satisfying predetermined conditions" means that the coupling state index is equal to or exceeds a set predetermined threshold. On the other hand, if the coupling state index does not satisfy predetermined conditions, TX100 determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915.

[0440] [When the fourth condition is included as a condition for transitioning to rapid charging mode] TX100 executes the foreign object detection method using the "information used by TX100 to execute the foreign object detection method" received from RX200. If the result of the foreign object detection method satisfies predetermined conditions, TX100 determines that the conditions for transitioning to rapid charging mode are met and proceeds to F2906. Here, "satisfying predetermined conditions" means that the result of foreign object detection by the foreign object detection method is that there are no foreign objects, or the probability of the presence of foreign objects is less than or equal to a predetermined value. On the other hand, if the result of foreign object detection by the foreign object detection method does not satisfy the predetermined conditions, TX100 determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915.

[0441] [When the fifth condition is included as a condition for transitioning to rapid charging mode] When TX100 receives a packet from RX200 containing "timing information indicating the timing at which TX100 acquires temperature information from TX100's temperature sensor", TX100 acquires the value of TX100's temperature sensor at the timing of receiving the packet. Then, TX100 determines whether or not the conditions for transitioning to rapid charging mode are met. If the acquired value of TX100's temperature sensor meets the predetermined conditions, TX100 determines that the conditions for transitioning to rapid charging mode are met and proceeds to F2906. Here, "meeting the predetermined conditions" means that the value of the temperature sensor is less than or equal to a predetermined value. "Not meeting the predetermined conditions" means that the value of the temperature sensor is greater than or equal to a predetermined value or exceeds a predetermined value. On the other hand, if the value of TX100's temperature sensor does not meet the predetermined conditions, TX100 determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915. Here, "failure to meet the specified conditions" means that the temperature sensor value of the TX100 exceeds or is equal to a specified value.

[0442] In the example described above, TX100 acquires the temperature sensor value of TX100 at the timing when it receives "timing information indicating when TX100 should acquire temperature information from TX100's temperature sensor" from RX200. However, it is not limited to this, and for example, TX100 may acquire temperature information from its temperature sensor at a timing determined by TX100 at predetermined intervals.

[0443] Furthermore, the TX100 is not limited to determining whether or not to switch to rapid charging mode based on the acquired temperature sensor values. For example, the TX100 may calculate the temperature rise rate based on multiple temperature detection values ​​acquired at predetermined timings. In this case, the TX100 may determine that the conditions for switching to rapid charging mode are met if the temperature rise rate is below a predetermined threshold or less than a predetermined threshold. The TX100 may also determine that the conditions for switching to rapid charging mode are not met if the temperature rise rate exceeds a predetermined threshold or is greater than or equal to a predetermined threshold.

[0444] Furthermore, RX200 may acquire the value from its temperature sensor and send a packet containing "temperature information from the RX200's temperature sensor" to TX100. This information may also include information used to determine the temperature threshold to be set. In this case, if the received value from the RX200's temperature sensor meets a predetermined condition, TX100 determines that the conditions for transitioning to rapid charging mode are met and proceeds to F2906. Here, "meeting the predetermined condition" means that the value from the RX200's temperature sensor is less than or equal to a predetermined value. If the value from the RX200's temperature sensor does not meet the predetermined condition, TX100 determines that the conditions for transitioning to rapid charging mode are not met and proceeds to F2915. Here, "not meeting the predetermined condition" means that the value from the RX200's temperature sensor exceeds a predetermined value or is greater than or equal to a predetermined value.

[0445] Furthermore, the TX100 may calculate the temperature rise rate based on the values ​​of multiple temperature sensors obtained from the RX200, and determine that the conditions for transitioning to rapid charging mode are met if the temperature rise rate is below a predetermined threshold or less than a predetermined threshold. Conversely, the TX100 may determine that the conditions for transitioning to rapid charging mode are not met if the temperature rise rate exceeds a predetermined threshold or is greater than or equal to a predetermined threshold.

[0446] Using the method described above, the TX100 determines at F2905 whether the conditions for switching to rapid charging mode are met. The following describes the process from F2905 onward.

[0447] If TX100 determines in F2905 that the conditions for transitioning to rapid charging mode are met, it proceeds to F2906. Then, TX100 sends a packet to RX200 containing information indicating that the conditions for transitioning to rapid charging mode are met (F2906). An acknowledgment (ACK) is used as the packet. RX200 determines whether or not it has received a packet from TX100 containing information indicating that the conditions for transitioning to rapid charging mode are met (F3005). If RX200 has not received the packet from TX100 (for example, if it receives a negative response (NAK)), it performs the F3005 determination periodically or irregularly until a predetermined time has elapsed (No in F3005, No in F3018). If the RX200 does not receive a packet containing information indicating that the conditions for transitioning to rapid charging mode are met within a predetermined time (No in F3005, Yes in F3018), it terminates processing. In other words, the RX200 returns to the Selection phase.

[0448] If the RX200 receives a packet containing information indicating that the conditions for transitioning to rapid charging mode are met within a predetermined time (F3005: Yes), it operates as follows: The RX200 sends a packet to the TX100 containing information indicating that it is requesting to transition to rapid charging mode (F3006). The TX100 determines whether or not it has received a packet from the RX200 containing information indicating that it is requesting to transition to rapid charging mode (F2907). The FOD Status data packet is used as the packet in question. This packet has a 1-bit field indicating whether or not it is requesting to transition to rapid charging mode. If the RX200 requests the TX100 to transition to rapid charging mode, it stores "1" (or "0") in the field; if it does not request the TX100 to transition to rapid charging mode, it stores "0" (or "1") in the field. Note that if the packet is used in the Negotiation phase, a different packet may be used instead of the FOD Status data packet.

[0449] If TX100 does not receive the packet containing information requesting to switch to rapid charging mode (No in F2907), it proceeds to F2915. If TX100 does receive the packet (Yes in F2907), it sends an acknowledgment (ACK) to RX200 (F2908). Then TX100 proceeds to F2909. RX200 determines whether or not it has received an ACK from TX100 (F3007). If RX200 does not receive an ACK from TX100, it periodically or irregularly makes the determination in F3007 until a predetermined time has elapsed (No in F3007, No in F3019). If RX200 has not received an ACK after the predetermined time has elapsed (No in F3007, Yes in F3019), it terminates processing. That is, RX200 returns to the Selection phase. If RX200 receives an ACK from TX100 (Yes in F3007), it proceeds to F3008.

[0450] The following describes the operation of the rapid charging mode on the TX100 from model F2909 onwards.

[0451] In F2909, the TX100 performs negotiation / renegotiation corresponding to the power in fast charging mode. Specifically, the TX100 can set the Negotiable Load Power to over 15 watts. More specifically, the TX100 can set the Negotiable Load Power to Potential Load Power. Potential Load Power is the highest GP level that the TX100 can negotiate. This makes it possible to set the GP to over 15 watts. However, the Negotiable Load Power may not be set to Potential Load Power due to other conditions. As a result, even in fast charging mode, the GP is not necessarily set to more than 15 watts. Negotiation / Renegotiation is an operation performed in the Negotiation phase described above. Through the control described above, the TX100 and RX200 agree on the GP through negotiation.

[0452] Then, TX100 proceeds to F2910 and executes CAL processing / ReCAL processing corresponding to the power of the rapid charging mode. CAL processing / ReCAL processing is an operation performed in the Calibration phase described above. Note that TX100 may be controlled so that the number of calibration points created by CAL processing / ReCAL processing in rapid charging mode is greater than the number of calibration points created by CAL processing / ReCAL processing when operating in BPP or EPP mode. Additionally or alternatively, TX100 may be controlled to create a predetermined number or more of calibration points in CAL processing / ReCAL processing in rapid charging mode. A "determined number" is, for example, "3" or a number of 4 or more. Alternatively, TX100 may determine the number of calibration points created by CAL processing / ReCAL processing in rapid charging mode according to the value of GP. For example, the number of calibration points may be set to "3" when the GP is 20 watts, to "4" when the GP is 30 watts, and to "5" when the GP is 40 watts. The method for determining the number of calibration points described above is applicable to the "CAL processing of the coupling state index measurement method" described above. When the number of calibration points is N (where N is an integer greater than or equal to 3), linear interpolation may be performed between each of two adjacent points as described above, or interpolation may be performed using a single N-1 polynomial.

[0453] The TX100 may also be controlled to create calibration points corresponding to the following power levels: Guaranteed Load Power, Requested Load Power, Negotiationable Load Power, Potential Load Power, and Maximum Power Value or Reference Power.

[0454] Furthermore, the method for creating the calibration points described above can be applied to the "CAL processing of the coupling state index measurement method" described above.

[0455] Next, TX100 proceeds to F2911 and begins transmitting power to RX200 at a rate of less than 5 watts or 5 watts or less. Then, TX100 proceeds to F2912 and performs authentication as defined by the WPC standard. Authentication here is the process by which RX200 authenticates TX100. Authentication includes the process by which RX200 determines whether TX100 is compatible with authentication. If RX200 determines that TX100 is compatible with authentication, it sends a predetermined first packet to TX100. RX200 determines whether the response from TX100 that received the predetermined packet satisfies predetermined conditions. If RX200 determines that the predetermined conditions are met, it sends a predetermined second packet to TX100. RX200 determines whether authentication was successful based on the content of the response from TX100 that received the predetermined packet (F2912). Alternatively, in the authentication process, in addition to the process in which RX200 authenticates TX100, TX100 may also perform a process in which it authenticates RX200. Authentication includes a process in which TX100 determines whether RX200 supports authentication. If TX100 determines that RX200 supports authentication, it sends a predetermined third packet to RX200. TX100 determines whether the response from RX200 that received the predetermined packet satisfies predetermined conditions. If TX100 determines that the predetermined conditions are met, it sends a predetermined fourth packet to RX200. TX100 determines whether authentication was successful based on the content of the response from RX200 that received the predetermined packet (F2912). In this case, authentication between TX100 and RX200 is considered successful only if RX200 successfully authenticates TX100, and TX100 successfully authenticates RX200.

[0456] If authentication is successful (Yes in F2912), TX100 proceeds to F2913 and executes control for fast charging mode operation. Successful authentication allows RX200 to receive power from the reliable TX100. Therefore, when RX200 attempts to receive high power in fast charging mode from TX100, it is controlled to switch to fast charging mode only if authentication is successful. Fast charging mode enables power transmission up to GP determined in F2909. On the other hand, if authentication fails (No in F2912), TX100 proceeds to F2915.

[0457] The operation of F2913 is a control mechanism designed to resolve issues encountered during rapid charging mode operation. Next, TX100 proceeds to F2914 and begins power transmission in rapid charging mode.

[0458] The above explains the operation of F2909 through F2914.

[0459] Next, we will explain the operation of the TX100 from F2915 onwards. The operation from F2915 onwards is the operation when it is decided to operate in BPP or EPP mode, rather than in rapid charging mode.

[0460] In F2915, the TX100 performs Negotiation / Renegotiation corresponding to the BPP / EPP power. Negotiation / Renegotiation is an operation performed in the Negotiation phase described above. The TX100 and RX200 set the GP to 5 watts or less for BPP or 15 watts or less for EPP. Specifically, the TX100 sets the Negotiationable Load Power to 5 watts or less or 15 watts or less. This sets the GP to 5 watts or less or 15 watts or less.

[0461] Then, TX100 proceeds to F2916 and performs CAL processing / ReCAL processing corresponding to the BPP / EPP power. CAL processing / ReCAL processing is an operation performed in the Calibration phase described above.

[0462] Next, TX100 proceeds to F2917 and starts power transmission to RX200 in BPP or EPP.

[0463] The operations from F2915 to F2917 have been described above.

[0464] Next, the operations of the rapid charging mode after F3008 of RX200 will be described.

[0465] At F3008, RX200 executes Negotiation / Renegotiation corresponding to the power of the rapid charging mode. Specifically, RX200 can set the Requested Load Power to more than 15 watts. As a result, GP can be made more than 15 watts. However, even in the rapid charging mode, GP is not necessarily set to more than 15 watts. Negotiation / Renegotiation is an operation executed in the above-described Negotiation phase. Through the above-described control, TX100 and RX200 reach an agreement on GP through negotiation.

[0466] Then, RX200 proceeds to F3009 and executes the CAL process / ReCAL process corresponding to the power of the rapid charging mode. Since this process is as described for the operation of F2910 above, the description is omitted.

[0467] Next, RX200 proceeds to F3010 and starts power reception of less than 5 watts or 5 watts or less from TX100. Then, RX200 proceeds to F3011 and executes the authentication defined by the WPC standard. If the authentication is successful (Yes at F3011), RX200 proceeds to F3012 and executes "control during rapid charging mode operation". Then, RX200 proceeds to F3013 and starts power reception in the rapid charging mode. If the authentication fails (No at F3011), RX200 proceeds to F3014.

[0468] The operations from F3008 to F3013 have been described above.

[0469] Next, we will explain the operation of the RX200 from F3014 onwards. The operation from F3014 onwards is the operation when it is decided to operate in BPP or EPP mode, rather than in rapid charging mode.

[0470] In F3014, the RX200 performs Negotiation / Renegotiation corresponding to the BPP / EPP power. Negotiation / Renegotiation is an operation performed in the Negotiation phase described above. The TX100 and RX200 set the GP to 5 watts or less for BPP or 15 watts or less for EPP. Specifically, the RX200 sets the Requested Load Power to 5 watts or less or 15 watts or less. This sets the GP to 5 watts or less or 15 watts or less.

[0471] Next, RX200 proceeds to F3015 and executes CAL processing / ReCAL processing corresponding to the BPP / EPP power. This processing is the same as described above for the operation of F2916, so the explanation will be omitted. Next, RX200 proceeds to F3016 and starts receiving power from TX100 in BPP or EPP mode.

[0472] The operation of F3014 through F3016 has been explained above.

[0473] Figure 31 is a sequence diagram showing the case where power is transmitted from TX100 to RX200 in rapid charging mode.

[0474] First, the RX200 requests information from the TX100 indicating whether or not it supports the rapid charging mode (S3101), and the TX100 receives this request (S3102). The TX100 and RX200 each notify the other that they support the rapid charging mode (S3103, S3104).

[0475] The RX200 notifies the TX100 of information to determine whether the conditions for transitioning to rapid charging mode are met (S3105). Based on this information, the TX100 determines whether the conditions for transitioning to rapid charging mode are met (S3106). Since the conditions for transitioning to rapid charging mode are met, the TX100 notifies that the conditions for transitioning to rapid charging mode are met (S3107).

[0476] Next, RX200 notifies that it requests to switch to fast charging mode (S3108). Then TX100 sends an acknowledgment (ACK) (S3109). Subsequently, TX100 and RX200 perform negotiation / renegotiation corresponding to the power of fast charging mode (S3110).

[0477] Next, TX100 and RX200 perform CAL processing / ReCAL processing corresponding to the power of the rapid charging mode (S3111). Then, RX200 performs authentication of TX100 (S3112). Also, TX100 performs authentication of RX200 (S3112). If authentication is successful (S3113), TX100 and RX200 perform "control during rapid charging mode operation" (S3114). Then, TX100 and RX200 start transmitting and receiving power in rapid charging mode (S3115).

[0478] The order of operations S3101 to S3107 until RX200 notifies TX100 of its request to switch to rapid charging mode may differ. For example, operations S3105 to S3107 may be performed first, followed by operations S3101 to S3104. In that case, if S3106 determines that TX100 does not meet the conditions for switching to rapid charging mode, TX100 may not perform S3107, and TX100 and RX200 may also not perform operations S3101 to S3104.

[0479] The above describes the procedure for switching the RX200 and TX100 into fast charging mode.

[0480] TX100 and RX200 begin transmitting and receiving power (F2914, F3013) and transition to the Power Transfer phase. After transitioning to the Power Transfer phase in rapid charging mode, TX100 and RX200 perform the control described in the first to fifth embodiments. This makes it possible to appropriately perform predetermined processes of TX100 or RX200 that are executed during wireless power transmission, such as NFC scanning, temperature control, and power saving, even when transmitting high power (high power) from TX100 to RX200.

[0481] <Other Embodiments> Regarding the control of TX100 and RX200 as described in the first to sixth embodiments, other embodiments are also possible. Other embodiments will be described below.

[0482] In the first to sixth embodiments, it was explained that when TX100 and RX200 are in the Cloak phase, TX100 transmits a Detect Ping to RX200 during the period when power transmission from TX100 to RX200 is temporarily suspended. TX100 may include predetermined information in this Detect Ping. This predetermined information may include, for example, "identification information that identifies TX100 as the source of the Ping," or "information indicating that this Ping is a Detect Ping used by RX200 to detect TX100." This makes it easier for RX200 to recognize the presence of TX100 through the Detect Ping.

[0483] In the second and fourth embodiments, a method was described in which TX100 requests RX200 to start Cloak when it determines that predetermined conditions are met, and then starts Cloak. Furthermore, it was assumed that if TX100 starts Cloak, TX100 will always terminate Cloak. However, if RX200 starts Cloak termination processing when TX100 starts Cloak, TX100 may send a packet to RX200 rejecting RX200's Cloak termination processing. This "packet rejecting RX200's Cloak termination processing" is, for example, a packet with Value "1" and reason code "Clak: Forced (Denied uncloak request)". This packet is shown as a Cloak Request Data Packet in Figures 13A and 13B. TX100 may also send a Cloak Request Data Packet containing the above reason code in response to the packet sent by RX200 during Cloak termination processing. The packet sent by RX200 during Cloak termination processing is a PRx Report [PRx Identification] Packet (REPORT [PRx ID], PRx ID report packet). Alternatively, the packet that RX200 sends during the Cloak termination process is a Get Request [PTx Extended Identification] Packet (GET [PTx XID]).

[0484] In this case, RX200 interrupts (stops) the Cloak termination process and sends a Cloak Data Packet to TX100 to continue the Cloak. This prevents RX200 from unilaterally terminating the Cloak when TX100 determines that certain conditions are met and starts the Cloak.

[0485] In the first, third, and fifth embodiments, a case was described in which RX200 terminates Cloak when it starts Cloak to execute a predetermined process, and TX100 does not request RX200 to terminate Cloak. However, when RX200 starts Cloak to execute a predetermined process, TX100 may request RX200 to terminate Cloak, taking into account the reason why RX200 started Cloak and the state of TX100. In this case, TX100 notifies RX200 of the "reason for requesting termination of Cloak". In addition, RX200 may transmit to TX100 an indicator (priority) showing how much priority RX200 wants to give to executing Cloak, in addition to the reason code for executing Cloak. As a result, TX100 considers the reason why RX200 initiated the cloak, an indicator of how much priority RX200 wants to give to executing the cloak, and the state of TX100, to determine whether or not to request RX200 to terminate the cloak. This makes it possible to make a more appropriate decision.

[0486] In the second and fourth embodiments, the case was described in which TX100 starts Cloak to execute a predetermined process, and TX100 terminates Cloak, and RX200 does not request TX100 to terminate Cloak. However, when TX100 requests to start Cloak to execute a predetermined process and starts Cloak, RX100 may operate as follows. That is, RX100 may consider the reason why TX100 requested to start Cloak and the state of RX200, and send a packet to TX100 to terminate Cloak. In this case, RX200 notifies TX100 of the "reason for requesting to terminate Cloak". In addition, TX100 may send to RX200 an indicator (priority) showing how much priority TX100 wants to give to executing Cloak, in addition to the reason code for requesting to start Cloak. This allows RX200 to determine whether or not to send a packet to terminate the closure, taking into account the reason TX100 requested the closure to begin, an indicator of how much priority TX100 wants to give to executing the closure, and the state of RX200. As a result, a more appropriate decision can be made.

[0487] In the first and second embodiments, if the reason code included in the packet transmitted by TX100 or RX200 is "Coex Mitigation" (execution of NFC scan), TX100 or RX200 operates as follows: That is, TX100 or RX200 sets Detect Ping to Disable and sets the Cloak time to, for example, 5 seconds, which is sufficient to perform an NFC scan. Then, in the third and fourth embodiments, if the reason code included in the packet transmitted by TX100 or RX200 is "Thermally constrained" (temperature control), TX100 or RX200 operates as follows: That is, TX100 or RX200 sets the transmission interval for Detect Ping, tcloakdetect, to, for example, 0.5 seconds, and the Cloak time to, for example, 60 seconds. In the first, second, third, and fourth embodiments, TX100 and RX200 are as described above. ｃｌｏａｋ You may also configure tcloakdetect. In other words, if the reason for performing Cloak is "NFC scanning", TX100 will not send a Detect Ping to avoid damaging the NFC tag. On the other hand, if the reason for performing Cloak is "temperature control", TX100 will send a Detect Ping at predetermined intervals so that RX200 can detect that it has been removed from TX100. Also, if the reason for performing Cloak is "performing an NFC scan", TX100 and RX200 will not send enough t to perform the NFC scan. ｃｌｏａｋ Set the following. On the other hand, if the reason for running Cloak is "temperature control", ensure that the RX200 or TX100 can dissipate heat sufficiently, as in the case where the reason for running Cloak is "running an NFC scan". ｃｌｏａｋ Longer than t ｃｌｏａｋ Set it.

[0488] Some (or possibly all) of the configurations in the above embodiments may be replaced with other configurations that perform similar functions, or omitted, or other configurations may be added. Furthermore, this disclosure is not limited to WPC standards and can be applied to various standards.

[0489] Furthermore, for example, the receiving device may possess some or all of the functions of the power transmission device. Alternatively, the receiving device may perform some or all of the processing that the power transmission device would normally perform.

[0490] Furthermore, the configurations in the above-described embodiments may be combined as appropriate.

[0491] Furthermore, the power transmission and receiving devices may be, for example, image input devices such as imaging devices (still cameras, video cameras, etc.) or scanners, or image output devices such as printers, copiers, or projectors. In addition, the power transmission and receiving devices may be storage devices such as hard disk drives or memory devices, or information processing devices such as personal computers (PCs), smartphones, or tablet devices.

[0492] Furthermore, the power receiving device in this disclosure may also be an information terminal device. For example, an information terminal device has a display unit that displays information to the user and is supplied with power received from a power receiving antenna. The power received from the power receiving antenna is stored in a power storage unit (battery), and power is supplied to the display unit from the battery. In this case, the power receiving device may also have a communication unit that communicates with other devices different from the power transmitting device. The communication unit may support communication standards such as NFC communication or fifth-generation mobile communication systems (5G).

[0493] Furthermore, the power receiving device in this disclosure may be a vehicle such as an automobile. For example, an automobile that is a power receiving device may receive power from a charger (power transmission device) via a power transmission antenna installed in a parking lot. Alternatively, an automobile that is a power receiving device may receive power from a charger (power transmission device) via a power transmission antenna embedded in the road. Such an automobile supplies the received power to a battery. The power from the battery may be supplied to a drive unit (motor, electric unit) that drives the wheels, or it may be used to drive sensors used for driving assistance or a communication unit that communicates with external devices. In other words, in this case, the power receiving device may have a battery, motors and sensors that are driven using the received power, and a communication unit that communicates with devices other than the power transmission device, in addition to the wheels. Furthermore, the power receiving device may have a compartment for accommodating people. For example, sensors may be used to measure the distance between vehicles or the distance to other obstacles. The communication unit may, for example, be compatible with the Global Positioning System (Global Positioning Satellite, GPS). The communication unit may also be compatible with communication standards such as the fifth-generation mobile communication system (5G). Furthermore, the vehicle may be a bicycle or a motorcycle.

[0494] Furthermore, the power receiving device in this disclosure may be a power tool, a home appliance, or the like. These power receiving devices may have a battery, as well as a motor driven by the power received from the battery. These devices may also have a notification means for notifying the remaining battery level, etc. These devices may also have a communication unit for communicating with other devices different from the power transmitting device. The communication unit may support communication standards such as NFC or fifth-generation mobile communication systems (5G).

[0495] Furthermore, the power transmission device of this disclosure may also be an in-vehicle charger that transmits power to portable information terminal devices such as smartphones and tablets that support wireless power transmission within a vehicle.

[0496] Such in-car chargers can be installed anywhere inside the vehicle. For example, they may be installed on the car's console, on the instrument panel (dashboard), between the passenger seats, on the ceiling, or on the doors.

[0497] However, it is best not to install them in locations that would interfere with driving. Also, although the power transmission device was explained using the example of an on-board charger, such chargers are not limited to those installed in vehicles; they may also be installed in transport vehicles such as trains, aircraft, and ships. In this case, the chargers may also be installed between passenger seats, on the ceiling, or on doors.

[0498] Alternatively, a vehicle such as an automobile equipped with an on-board charger may also serve as a power transmission device. In this case, the power transmission device has wheels and a battery, and uses the power from the battery to supply power to the power receiving device via a power transmission circuit and a power transmission antenna.

[0499] This disclosure can also be implemented by supplying a program that implements one or more of the functions of the embodiments described above to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. Furthermore, this disclosure can also be implemented by a circuit (e.g., ASIC) that implements one or more functions.

[0500] Furthermore, some of the processes described in this disclosure with reference to the flowchart may be implemented in hardware. For example, a dedicated circuit can be automatically generated on the FPGA from a program to implement each step by using a predetermined compiler. Alternatively, a Gate Array circuit may be formed in the same way as the FPGA and implemented in hardware.

[0501] Furthermore, the following additional information is disclosed regarding the above embodiments.

[0502] [Note 1] A power receiving device comprising: a power receiving means for receiving power wirelessly from a power transmitting device; and a transmitting means for transmitting a first packet to the power transmitting device to terminate the temporary suspension when the power receiving means has temporarily suspended power reception from the power transmitting device, wherein the first condition is at least one of the following: no NFC (Near Field Communication) tag is detected by an NFC scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

[0503] [Note 2] The power receiving device according to Note 1, characterized in that the power receiving means resumes receiving power from the power transmitting device, which has been temporarily suspended, after the transmitting means has transmitted the first packet.

[0504] [Note 3] The power receiving device according to Note 1 or 2, characterized in that the transmitting means transmits a second packet to the power transmitting device to initiate the temporary suspension of power reception when the power receiving means is receiving power from the power transmitting device and a second condition for temporary suspension of power reception is met.

[0505] [Note 4] The power receiving device according to Note 3, characterized in that the second packet includes information indicating that the power transmitting device is prohibited from requesting the power receiving device to terminate the temporary suspension of power transmission to the power receiving device by the power transmitting device.

[0506] [Note 5] The power receiving device according to any one of Notes 1 to 4, characterized in that it operates in a mode (rapid charging mode) in which the power received from the power transmission device exceeds a predetermined value.

[0507] [Note 6] The power receiving device according to Note 5, characterized in that it can switch to the mode when the indicator of the coupling state between the power transmitting device and the power receiving device exceeds a predetermined value.

[0508] [Note 7] The power receiving device according to Note 3, characterized in that the second packet includes information indicating the reason for the temporary pause.

[0509] [Note 8] The power receiving device according to Note 3, characterized in that the second condition is that the indicator of the coupling state between the power transmitting device and the power receiving device is less than or equal to a predetermined value.

[0510] [Note 9] The power receiving device according to Note 3, characterized in that the second condition is that the temperature of the power receiving device is above a predetermined value.

[0511] [Note 10] The power receiving device according to Note 3, characterized in that the second condition is that the charge level of the battery of the power receiving device exceeds a predetermined value.

[0512] [Note 11] A power transmission device comprising: a power transmission means for wirelessly transmitting power to a power receiving device; and a receiving means for receiving a first packet from the power receiving device to terminate the temporary suspension when the power transmission means has temporarily suspended power reception to the power receiving device, wherein the first condition is at least one of the following: no NFC (Near Field Communication) tag is detected by an NFC scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

[0513] [Note 12] The power transmission device according to Note 11, characterized in that the power transmission means resumes power transmission to the power receiving device, which has been temporarily suspended, after the receiving means has received the first packet.

[0514] [Note 13] The power transmission device according to Note 11 or 12, characterized in that the receiving means receives a second packet for initiating the temporary suspension of power transmission from the power receiving device when the power transmission means is transmitting power to the power receiving device, in response to the second condition for temporary suspension of power transmission being met.

[0515] [Note 14] The power transmission device according to Note 13, characterized in that the second packet includes information indicating that the power transmission device is prohibited from requesting the power receiving device to terminate the temporary suspension of power transmission by the power transmission device to the power receiving device.

[0516] [Note 15] The power transmission device according to any one of Notes 11 to 14, characterized in that it operates in a mode (rapid charging mode) in which the power transmitted to the power receiving device exceeds a predetermined value.

[0517] [Note 16] The power transmission device according to Note 13, characterized in that the second packet includes information indicating the reason for the temporary pause.

[0518] [Note 17] The power transmission device according to Note 13, characterized in that the second condition is that the indicator of the coupling state between the power transmission device and the power receiving device is less than or equal to a predetermined value.

[0519] [Note 18] The power transmission device according to Note 13, characterized in that the second condition is that the temperature of the power receiving device is above a predetermined value.

[0520] [Note 19] The power transmission device according to Note 13, characterized in that the second condition is that the charge level of the battery of the power receiving device exceeds a predetermined value.

[0521] [Note 20] A method performed by a power receiving device, comprising: receiving power wirelessly from a power transmitting device; temporarily suspending power reception from the power transmitting device; and, while power reception from the power transmitting device is temporarily suspended, sending a packet to the power transmitting device to terminate the temporary suspension when a condition for resuming power reception is met, wherein the first condition is at least one of the following: no NFC tag is detected by an NFC (Near Field Communication) scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

[0522] [Note 21] A method performed by a power transmission device, comprising: the steps of: wirelessly transmitting power to a power receiving device; temporarily suspending power reception to the power receiving device; and, while power reception to the power receiving device is temporarily suspended, receiving a packet from the power receiving device to terminate the temporary suspension in accordance with the fulfillment of conditions for resuming power transmission, wherein the first condition is at least one of the following: no NFC tag is detected by an NFC (Near Field Communication) scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

[0523] [Note 23] A program that causes a computer to perform the method described in Note 20 or 21.

[0524] The present invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are attached to make the scope of the invention public.

[0525] This application claims priority based on Japanese Patent Application No. 2024-188793, filed on 28 October 2024, and all of its contents are incorporated herein by reference.

Claims

1. A power receiving device comprising: a power receiving means for receiving power wirelessly from a power transmitting device; and a transmitting means for transmitting a first packet to the power transmitting device to terminate the temporary suspension when the power receiving means has temporarily suspended power reception from the power transmitting device, wherein the first condition is at least one of the following: no NFC (Near Field Communication) tag is detected by an NFC scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

2. The power receiving means is characterized in that it resumes receiving power from the power transmitting device, which has been temporarily suspended, after the transmitting means has transmitted the first packet.

3. The power receiving device according to claim 1 or 2, characterized in that the transmitting means transmits a second packet to the power transmitting device to initiate the temporary suspension of power reception when the power receiving means is receiving power from the power transmitting device, in response to the second condition relating to the temporary suspension of power reception being met.

4. The power receiving device according to claim 3, characterized in that the second packet includes information indicating that the power transmitting device is prohibited from requesting the power receiving device to terminate the temporary suspension of power transmission by the power transmitting device to the power receiving device.

5. The power receiving device according to claim 1, characterized in that it operates in a mode in which the power received from the power transmission device exceeds a predetermined value.

6. The power receiving device according to claim 5, characterized in that it can transition to the mode when an index of the coupling state between the power transmitting device and the power receiving device exceeds a predetermined value.

7. The power receiving device according to claim 3, characterized in that the second packet includes information indicating the reason for the temporary pause.

8. The power receiving device according to claim 3, characterized in that the second condition is that the indicator of the coupling state between the power transmitting device and the power receiving device is less than or equal to a predetermined value.

9. The power receiving device according to claim 3, characterized in that the second condition is that the temperature of the power receiving device is above a predetermined value.

10. The power receiving device according to claim 3, characterized in that the second condition is that the charge level of the battery of the power receiving device exceeds a predetermined value.

11. A power transmission device comprising: a power transmission means for wirelessly transmitting power to a power receiving device; and a receiving means for receiving a first packet from the power receiving device to terminate the temporary suspension when the power transmission means has temporarily suspended power reception to the power receiving device, wherein the first condition is at least one of the following: no NFC (Near Field Communication) tag is detected by an NFC scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

12. The power transmission device according to claim 11, characterized in that the power transmission means resumes power transmission to the power receiving device, which has been temporarily suspended, after the receiving means has received the first packet.

13. The power transmission device according to claim 11 or 12, characterized in that the receiving means receives a second packet for initiating the temporary suspension of power transmission from the power receiving device when the power transmission means is transmitting power to the power receiving device, in response to the second condition for temporary suspension of power transmission being met.

14. The power transmission device according to claim 13, characterized in that the second packet includes information indicating that the power transmission device is prohibited from requesting the power receiving device to terminate the temporary suspension of power transmission by the power transmission device to the power receiving device.

15. The power transmission device according to claim 11, characterized in that it operates in a mode in which the power transmitted to the power receiving device exceeds a predetermined value.

16. The power transmission device according to claim 13, characterized in that the second packet includes information indicating the reason for the temporary suspension.

17. The power transmission device according to claim 13, characterized in that the second condition is that the indicator of the coupling state between the power transmission device and the power receiving device is less than or equal to a predetermined value.

18. The power transmission device according to claim 13, characterized in that the second condition is that the temperature of the power receiving device is above a predetermined value.

19. The power transmission device according to claim 13, characterized in that the second condition is that the charge level of the battery of the power receiving device exceeds a predetermined value.

20. A method performed by a power receiving device, comprising: receiving power wirelessly from a power transmitting device; temporarily suspending power reception from the power transmitting device; and, while power reception from the power transmitting device is temporarily suspended, transmitting a packet to the power transmitting device to terminate the temporary suspension in response to the fulfillment of conditions for resuming power reception, wherein the first condition is at least one of the following: no NFC tag is detected by an NFC (Near Field Communication) scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

21. A method performed by a power transmission device, comprising: the steps of: wirelessly transmitting power to a power receiving device; temporarily suspending power reception to the power receiving device; and, while power reception to the power receiving device is temporarily suspended, receiving a packet from the power receiving device to terminate the temporary suspension in response to the fulfillment of conditions for resuming power transmission, wherein the first condition is at least one of the following: no NFC (Near Field Communication) tag is detected by an NFC scan performed by the power receiving device; the temperature of the power receiving device is below a predetermined value; and the charge level of the battery of the power receiving device is below a predetermined value.

22. A program for causing a computer to perform the method described in claim 20 or 21.

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