Power receiving device, power transmitting device, communication method, and program

Abstract

The power receiving device (200) transmits the identification packet and the extended identification packet to the power transmitting device (100). The identification data packet contains information for identifying the powered device (200). The extended identification data packet contains information for indicating the power scheme.

Description

Technical Field

[0001] The present disclosure relates to wireless power transmission technology. Background Art

[0002] In a wireless power transmission system, a power transmitting device transmits power to a power receiving device placed on a charging base, etc. Wireless charging requires faster charging. Patent Document 1 describes control in fast wireless charging.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-108014 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] High power transmission is performed in fast wireless charging; however, with existing technologies, there is a possibility that high power transmission cannot be performed properly depending on the status of the power transmitting device and the power receiving device. The present disclosure aims to provide a technology that enables appropriate fast wireless charging.

[0008] Means used to solve problems

[0009] A power receiving device of the present disclosure includes: a power receiving unit configured to wirelessly receive power from a power transmitting device; and a transmission unit configured to transmit an identification data packet and an extended identification data packet to the power transmitting device, wherein the identification data packet includes information identifying the power receiving device and the extended identification data packet includes information indicating a power profile.

[0010] According to the present disclosure, proper fast wireless charging can be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a diagram showing a configuration example of a wireless power transmission system.

[0012] Figure 2 : is a diagram showing a configuration example of a power transmitting device.

[0013] Figure 3 is a diagram showing a configuration example of a power receiving device.

[0014] Figure 4 : is a diagram showing a threshold setting method in state detection using a power loss method.

[0015] Figure 5A is a diagram showing a quality factor measurement method.

[0016] Figure 5B is a graph showing a quality factor measurement method.

[0017] Figure 6 is a block diagram showing a functional configuration example of a control unit of a power transmitting device.

[0018] Figure 7 This is a flowchart showing the processing of the power transmitting device.

[0019] Figure 8 is a flowchart showing the processing of the power receiving device.

[0020] Figure 9 is a diagram illustrating state detection using a waveform decay method.

[0021] Figure 10 2 is a diagram illustrating an example of a process for performing wireless power transmission.

[0022] Figure 11 is a graph showing a threshold value setting method in state detection using the waveform decay method.

[0023] Figure 12A This is a diagram showing a method for measuring a coupling state index between a power transmitting antenna and a power receiving antenna.

[0024] Figure 12B This is a diagram showing a method for measuring a coupling state index between a power transmitting antenna and a power receiving antenna.

[0025] Figure 13 : is a graph showing a threshold setting method in state detection using the coupling state index measurement method.

[0026] Figure 14 1 is a flowchart illustrating the processing of the power transmitting device of the first embodiment.

[0027] Figure 15 : is a flowchart showing the processing of the power receiving apparatus of the first embodiment.

[0028] Figure 16 1 is a sequence diagram illustrating processing by the power transmitting apparatus and the power receiving apparatus of the first embodiment.

[0029] Figure 17 1 is a flowchart illustrating processing of the power transmitting device according to the third embodiment.

[0030] Figure 18 : is a flowchart showing the processing of the power receiving apparatus of the third embodiment.

[0031] Figure 19 1 is a sequence diagram illustrating processing by the power transmitting apparatus and the power receiving apparatus according to the third embodiment. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. A plurality of features are described in each embodiment; however, not all of the plurality of features are essential to the present invention, and a plurality of features may be used in any combination. In addition, in the accompanying drawings, similar reference numerals represent the same or similar components. The various embodiments illustrate a wireless charging system to which a wireless power transmission system is applied. In an example, wireless power transmission based on a standard (hereinafter referred to as the WPC standard) formulated by a wireless charging standardization organization (i.e., the Wireless Power Consortium) will be described.

[0033] [First embodiment]

[0034] The present embodiment will be described with reference to the accompanying drawings. Figure 1 1 is a diagram showing a configuration example of a wireless charging system. The system includes a power transmitting device 100 , a power receiving device 200 , and a charging base 300 .

[0035] Hereinafter, for the sake of brevity, the power receiving device 200 may be referred to as RX 200, and the power transmitting device 100 may be referred to as TX 100. Figure 2 and Figure 3 Describes the detailed configurations of the TX 100 and RX 200.

[0036] The RX 200 is an electronic device that charges its built-in battery by receiving power from the TX 100 when placed on the charging base 300. The TX 100 is an electronic device that wirelessly transmits power to the RX 200 placed on the charging base 300. Since the charging base 300 constitutes a part of the TX 100, the sentence that the RX 200 is "placed on the charging base 300" can be replaced with the sentence that the RX 200 is "placed on the TX 100". Figure 1 The range indicated by the dashed box 400 in the figure schematically illustrates the spatial range within which the RX 200 can receive power from the TX 100. Each of the RX 200 and the TX 100 may have the function of executing applications other than wireless charging. For example, the RX may be a smartphone and the TX may be an accessory device for charging the RX's battery. However, this configuration is not limited to this example.

[0037] Next, we will refer to Figure 2 A configuration example of the power transmitting device 100 is described. Figure 2 1 is a functional block diagram showing a configuration example of a power transmission device 100. The TX 100 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 is abbreviated as UI. Figure 2 In the figures, the various functional block elements are shown as separate units; however, selected multiple functional block elements can be implemented in the same chip.

[0038] The control unit 101 controls the entire TX 100 by running a control program stored in the memory 106. The control unit 101 performs power transmission control in the TX 100, including communication for device authentication. In addition, the control unit 101 can perform control for running applications other than wireless power transmission. The control unit 101 is configured to include one or more processors (such as a central processing unit (CPU) and a microprocessor unit (MPU)). Alternatively, the control unit 101 can be made of hardware such as an application-specific integrated circuit (ASIC). The control unit 101 can also be configured to include an array circuit such as a field programmable gate array (FPGA) compiled to perform predetermined processing. The control unit 101 can perform processing to store information to be stored during the execution of various processes in the memory 106, as well as clock processing using a timer (not shown).

[0039] The power supply unit 102 supplies power to each functional block element. The power supply unit 102 includes, for example, a power connection circuit for a commercial power source and a battery. The battery is charged with power supplied from the commercial power source.

[0040] 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 this AC power to the power transmission antenna 105, thereby generating electromagnetic waves for the RX 200 to receive power. For example, the power transmission unit 103 includes an inverter that converts the DC voltage supplied from the power supply unit 102 into AC voltage using a switching circuit having a half-bridge configuration or a full-bridge configuration. The power transmission unit 103 includes multiple field-effect transistors (FETs) that form a bridge and a gate driver that controls the on / off state of the multiple FETs.

[0041] The power transmission unit 103 controls the intensity of the electromagnetic waves to be output (transmitted power) by adjusting the voltage (transmitted voltage) or current (transmitted current) input to the power transmission antenna 105, or both. The intensity of the electromagnetic waves (the intensity of the transmitted power) is controlled by the magnitude of the transmission voltage or the transmission current. Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves to be output (transmitted power) by adjusting the voltage (inverter input voltage) or current (inverter input current) input to the inverter of the power transmission unit 103, or both. The voltage input to the inverter is referred to as the inverter input voltage. The current input to the inverter is referred to as the inverter input current. The intensity of the electromagnetic waves (the intensity of the transmitted power) is controlled by the magnitude of the inverter input voltage or the inverter input current.

[0042] Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves to be output (transmitted power) by adjusting the voltage (inverter output voltage) or current (inverter output current) output from the inverter of the power transmission unit 103, or both. The voltage output from the inverter is referred to as the inverter output voltage. The current output from the inverter is referred to as the inverter output current. The intensity of the electromagnetic waves (the intensity of the transmitted power) is controlled by the magnitude of the inverter output voltage or the inverter output current.

[0043] Power transmission unit 103 controls the output power of electromagnetic waves having an AC frequency so as to control the start or stop of power transmission by power transmission antenna 105 or the intensity of the electromagnetic waves to be output based on a command signal from control unit 101. It is assumed that power transmission unit 103 has a power supply capacity capable of outputting 50 watts (W) of power to the charging unit of power receiving device 200 that supports the WPC standard.

[0044] The first communication unit 104 is connected to the control unit 101 and the power transmission unit 103. The first communication unit 104 communicates with the RX 200 for power transmission control based on the WPC standard. The first communication unit 104 performs frequency shift keying on the electromagnetic waves output from the power transmission antenna 105 and transmits the information to the RX 200 for communication. The first communication unit 104 demodulates the electromagnetic waves modulated by the RX 200 and transmitted from the power transmission antenna 105 to obtain the information transmitted from the RX 200. Communication using the first communication unit 104 is performed by superimposing a communication signal on the electromagnetic waves transmitted from the power transmission antenna 105. The first communication unit 104 performs so-called in-band communication.

[0045] In addition to the control program, the memory 106 may also store information related to the status of the TX 100 and RX 200. The information related to the status of the TX 100 and RX 200 includes, for example, the transmitted power value and the received power value. The information related to the status of the TX 100 is acquired by the control unit 101. The information related to the status of the RX 200 can be acquired by the control unit of the RX 200 and received by the first communication unit 104 or the second communication unit 109 (described later).

[0046] Switching section 108 is connected in parallel to the series circuit of resonant capacitor 107 and power-transmitting antenna 105. Control section 101 transmits a control signal to switching section 108 to control its on and off states. Power-transmitting antenna 105 is connected to resonant capacitor 107. When switching section 108 is turned on and short-circuited by a control signal from control section 101, power-transmitting antenna 105 and resonant capacitor 107 form a series resonant circuit, resonating at a specific frequency fA. At this point, current flows through the closed circuit formed by power-transmitting antenna 105, resonant capacitor 107, and switching section 108. On the other hand, when switching section 108 is turned off and the circuit is open by a control signal from control section 101, power is supplied from power transmitting section 103 to power-transmitting antenna 105 and resonant capacitor 107.

[0047] The second communication unit 109 is connected to the control unit 101 and communicates with the RX 200 based on a standard different from the WPC standard. For example, the second communication unit 109 communicates with the RX 200 by using an antenna (not shown) different from the power transmission antenna 105. The communication methods used by the second communication unit 109 include wireless local area network (LAN), Bluetooth (registered trademark) low energy (BLE), and near field communication (NFC). BLE is a communication method that supports Bluetooth standard version 4.0 and higher. The frequency band used when transmitting power from the power transmission antenna 105 is different from the frequency band used for communication of the second communication unit 109. The second communication unit 109 performs so-called out-of-band communication.

[0048] Regarding communication between the TX 100 and the RX 200, the TX 100 can selectively use any of a plurality of communication standards to communicate with the RX 200. It is possible to selectively use a plurality of communication modes described below.

[0049] ● In the first communication unit 104 of TX 100 and the first communication unit 204 of RX 200 (see Figure 3 ) based on the first standard (WPC standard).

[0050] ● In the second communication unit 109 of TX 100 and the second communication unit 212 of RX 200 (see Figure 3 ) based on a second standard (a standard other than the WPC standard).

[0051] The UI unit 110 is connected to the control unit 101 and performs various outputs for the user. These outputs include screen display, blinking and color change of light-emitting diodes (LEDs), voice output through a speaker, and movement such as vibration of the main body of the TX 100. The UI unit 110 is implemented by a liquid crystal panel, a speaker, a vibration motor, or the like.

[0052] Next, we will refer to Figure 3 A configuration example of the power receiving apparatus 200 is described. Figure 3 2 is a block diagram showing a configuration example of a power receiving device 200. The RX 200 includes a control unit 201, a user interface (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. The RX 200 also includes a first switching unit 209, a second switching unit 210, a resonant capacitor 211, a second communication unit 212, and a third switching unit 213. This embodiment describes Figure 3 The functional block elements in FIG. 1 are examples of separate elements; however, multiple functional block elements may be implemented by a single hardware module.

[0053] The control unit 201 controls the various functional block elements of the RX 200 by running a control program stored in the memory 208. In addition, the control unit 201 can perform control for running applications other than wireless power transmission. The control unit 201 is configured to include one or more processors such as a CPU and an MPU. The entire RX 200 (for example, the entire smartphone) can be controlled by cooperating with an operating system (OS) being executed by the control unit 201. Alternatively, the control unit 201 is composed of hardware such as an ASIC, or can be configured to include an array circuit such as an FPGA that is compiled to perform predetermined processing. The control unit 201 can store information to be stored during the execution of various processes in the memory 208, and also perform clock processing using a timer (not shown).

[0054] The UI unit 202 is connected to the control unit 201 and performs various outputs for the user. These outputs include screen display, blinking and color changes of light-emitting diodes (LEDs), voice output through the speaker, and motions such as vibration of the main body of the RX 200. The UI unit 202 is implemented by a liquid crystal panel, a speaker, a vibration motor, or the like.

[0055] The power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction of electromagnetic waves radiated from the power transmitting antenna 105 of the TX 100 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 with a predetermined frequency and supplies this power to the charging unit 206. The charging unit 206 charges the battery 207. The power receiving unit 203 includes a rectifier (rectifier, rectifier circuit) and a voltage control unit necessary to supply power to the load in the RX 200. The rectifier converts the AC voltage and AC current received from the power transmitting antenna via the power receiving antenna 205 into DC voltage and DC current. The DC voltage is referred to as the rectifier output voltage. The DC current is referred to as the rectifier output current. The voltage control unit converts the DC voltage (rectifier output voltage) output by the rectifier to a predetermined level. The predetermined level is a DC voltage level that can be operated by the control unit 201, the charging unit 206, and the like. The power receiving unit 203 is supplied with power for charging the battery 207 from the charging unit 206. Assume that the power receiving unit 203 has a power supply capability of outputting 50 watts of power to the charging unit 206.

[0056] The first communication unit 204 communicates with the first communication unit 104 of the TX 100 for power reception 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 to obtain information transmitted from the TX 100. The first communication unit 204 communicates with the TX 100 by superimposing a signal related to the information to be transmitted to the TX 100 on the electromagnetic waves by load modulation, amplitude modulation, or backscatter modulation of the input electromagnetic waves.

[0057] In addition to the control program, the memory 208 also stores, for example, information related to the status of the TX 100 and the RX 200. The control unit 201 acquires information related to the status of the RX 200. The information related to the status of the TX 100 can be acquired by the control unit 101 of the TX 100 and received by the first communication unit 204 or the second communication unit 212 (described later).

[0058] The second communication unit 212 is connected to the control unit 201 and communicates with the TX 100 based on a standard different from the WPC standard. For example, the second communication unit 212 communicates with the TX 100 using an antenna different from the power receiving antenna 205. The communication methods used by the second communication unit 212 include wireless LAN, BLE, and NFC. BLE is a communication method that supports Bluetooth standard version 4.0 and higher. The frequency band used when receiving power using the power receiving antenna 205 is different from the frequency band used for communication by the second communication unit 212.

[0059] Regarding communication between the TX 100 and the RX 200, the RX 200 can selectively use any of a plurality of communication standards to communicate with the TX 100. It is possible to selectively use a plurality of communication modes described below.

[0060] Communication based on the first standard (WPC standard) is performed between the first communication unit 104 of the TX 100 and the first communication unit 204 of the RX 200 .

[0061] Communication based on the second standard (a standard other than the WPC standard) performed between the second communication unit 109 of the TX 100 and the second communication unit 212 of the RX 200 .

[0062] The first switch unit 209 is provided 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 the power received by the power receiving unit 203 is supplied to the battery 207, and the function of controlling the load size. When the first switch unit 209 is turned off by the control unit 201 to open the circuit, 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 by the control unit 201 to short the circuit, the power received by the power receiving unit 203 is supplied to the battery 207.

[0063] exist Figure 3 , the first switch unit 209 is disposed between the charging unit 206 and the battery 207. Alternatively, the first switch unit 209 may be disposed between the power receiving unit 203 and the charging unit 206.

[0064] Alternatively, the first switch unit 209 may be disposed between the power receiving unit 203 and the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210. In this case, the first switch unit 209 has a function of controlling whether the power received by the power receiving antenna 205 is supplied to the power receiving unit 203.

[0065] exist Figure 3In the example shown, the first switch unit 209 is shown as a single functional block element; however, the first switch unit 209 can be implemented as part of the charging unit 206 or the power receiving unit 203. The configuration is not limited to inserting the first switch unit 209 in series between the charging unit 206 and the battery 207; the first switch unit 209 can also be inserted in parallel between the charging unit 206 and the battery 207. In this case, when the first switch unit 209 is set to the OFF state to open the circuit 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 set to the ON state to short the circuit by the control unit 201, the power received by the power receiving unit 203 is not supplied to the battery 207.

[0066] Second switch unit 210 is connected in parallel with resonant capacitor 211 on the input side of power receiving unit 203. Resonant capacitor 211 is connected to power receiving antenna 205 via third switch unit 213. Second switch unit 210 and third switch unit 213 are controlled by control unit 201. Third switch unit 213 controls whether to open the terminals of power receiving antenna 205. When control unit 201 turns third switch unit 213 off, the terminals of power receiving antenna 205 are open. When control unit 201 turns third switch unit 213 on, power receiving antenna 205 is connected to power receiving unit 203 via resonant capacitor 211.

[0067] When the third switch unit 213 is set to the ON state and the second switch unit 210 is set to the ON state to be short-circuited by the control unit 201, the power receiving antenna 205 and the resonant capacitor 211 form a series resonant circuit and resonate at a specific frequency fB. Current flows through the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211 and the second switch unit 210, and no current flows through the power receiving unit 203. When the second switch unit 210 is set to the OFF state to open the circuit, the power received by the power receiving antenna 205 and the resonant capacitor 211 is supplied to the power receiving unit 203. Not limited to Figure 3 In the example shown in FIG, the second switch unit 210 can be arranged between the power receiving antenna 205 and the resonant capacitor 211. When the third switch unit 213 is in the ON state and the second switch unit 210 is in the ON state, the terminals of the power receiving antenna 205 are short-circuited. The third switch unit 213 can be arranged between the resonant capacitor 211 and the power receiving unit 203.

[0068] In this system, the TX 100 and RX 200 perform wireless power transmission based on the WPC standard between the power transmitting antenna 105 and the power receiving antenna 205. In the WPC standard, the level of load power agreed upon between the RX 200 and TX 100 is predefined by a value called guaranteed load power (hereinafter referred to as "GP"). Load power is the power consumed by the load. For example, GP indicates a power value that is guaranteed to be output to the load of the RX 200 even if the positional relationship between the RX 200 and TX 100 fluctuates, weakening the coupling state between the power receiving antenna 205 and the power transmitting antenna 105 and resulting in reduced power transmission efficiency. The load of the RX 200 includes the charging unit 206 and the battery 207, among others. The GP value corresponds to the power guaranteed to be output from the power receiving unit 203. Alternatively, the GP value corresponds to the power guaranteed to be output from the rectifier section of the power receiving unit 203. For example, let's assume that the GP value is set to 5 watts and the positional relationship between the power receiving antenna 205 and the power transmitting antenna 105 has fluctuated. In this case, even when power transmission efficiency decreases, the TX 100 performs power transmission control so that 5 watts can be output to the load of the RX 200. The GP is determined by negotiation between the TX 100 and RX 200. This embodiment is not limited to the GP; it can be applied to a configuration in which power is transmitted and received using power determined by negotiation between the TX 100 and RX 200.

[0069] Assume that there is an object near TX 100 when power is transmitted from TX 100 to RX 200. In this case, the object is an object (foreign matter) that may affect the power transmission from TX 100 to RX 200 and is different from RX 200. The electromagnetic waves used for power transmission may affect the foreign object, and there is a possibility that the temperature of the foreign object will increase or damage will occur. Foreign matter in the present disclosure refers to an object that is neither part of the product assembled from the power receiving device and the power receiving device nor part of the product assembled from the power transmitting device and the power transmitting device, and an object that generates heat when exposed to a power signal. Examples of foreign matter include clips and IC cards. Among objects that are an integral part of the product assembled from the power receiving device and the power receiving device or the product assembled from the power transmitting device and the power transmitting device, an object that may unintentionally generate heat when exposed to wireless power transmitted by the power transmitting antenna is not a foreign matter.

[0070] The WPC standard predefines a method for suppressing temperature increases and damage to foreign objects by stopping power transmission when a foreign object is present. Specifically, the power transmitting device 100 can detect the presence of foreign objects on the charging base 300. The power loss method is a method for detecting foreign objects based on the difference between the transmitted power in the TX 100 and the received power in the RX 200. The quality factor measurement method is a method for detecting foreign objects based on changes in the quality factor (Q factor) of the power transmitting antenna 105 (power transmitting coil) in the TX 100. Alternatively, the quality factor measurement method is a method for detecting foreign objects based on changes in the quality factor (Q factor) of the resonant circuit including the power transmitting antenna 105 and the resonant capacitor 107 in the TX 100. In this disclosure, the quality factor of the power transmitting antenna 105 and the quality factor of the resonant circuit including the power transmitting antenna 105 and the resonant capacitor 107 are referred to as quality factors related to the power transmitting antenna 105. However, the foreign objects to be detected by the TX 100 are not limited to objects present on the charging base 300. The TX 100 can detect a foreign object located near the TX 100. For example, the TX 100 can detect a foreign object located within a range where the TX 100 can transmit power.

[0071] Will refer to Figure 4 Describes foreign object detection based on the power loss method predefined in the WPC standard. Figure 4 In the graph, the horizontal axis represents the transmitted power of the TX 100, and the vertical axis represents the received power of the RX 200. On the graph line represented by straight line segment 1002, point 1000 corresponds to the first transmitted power value Pt1 and the first received power value Pr1, and point 1001 corresponds to the second transmitted power value Pt2 and the second received power value Pr2. Point 1003 on the graph line corresponds to the third transmitted power value Pt3 and the third received power value Pr3. Foreign objects to be detected include conductive metal pieces and the like.

[0072] Initially, TX 100 transmits power to RX 200 at a first transmission power value Pt1, and RX 200 receives power at a first reception power value Pr1. Hereinafter, this state is referred to as a light load state. Then, TX 100 stores the first transmission power value Pt1. At this time, RX 200 performs load control so that the power to be received is minimum power. Alternatively, RX 200 performs load control so that the power to be received is power within a predetermined range or power lower than or equal to a predetermined threshold. Here, in "power within a predetermined range" or "power lower than or equal to a predetermined threshold", "power" refers to power of a value of about 10% of a reference power (described later). RX 200 may interrupt the load (such as Figure 3The RX 200 controls the load so that the received power is not supplied to the load (e.g., the charging unit 206 and the battery 207 in the RX 200). Alternatively, the RX 200 can control the load so that the predetermined power is supplied to the load. This can be achieved by controlling the first switching unit 209. Subsequently, the RX 200 notifies the TX 100 of the first received power value Pr1. When the TX 100 receives a signal related to the first received power value Pr1 from the RX 200, the TX 100 calculates the power loss between the TX 100 and the RX 200. The power loss at this time is Pt1 - Pr1 (= Ploss1). A calibration point (hereinafter referred to as CP) 1000 indicating the correspondence between Pt1 and Pr1 can be generated.

[0073] Subsequently, the TX 100 changes the transmission power value to the second transmission power value Pt2 and transmits power to the RX 200, and the RX 200 receives power at the second reception power value Pr2. This state is hereinafter referred to as the connected load state. The TX 100 then stores the second transmission power value Pt2. At this point, the RX 200 performs load control so that the power to be received is the maximum power. Here, "maximum power" refers to power with a value close to a reference power (described later). Alternatively, the RX 200 performs load control so that the power to be received is within a predetermined range or greater than or equal to a predetermined threshold. For example, the RX 200 connects the power receiving antenna 205 to the load so that the received power is supplied to the load. This can be achieved by controlling the first switch unit 209. Subsequently, the RX 200 notifies the TX 100 of the second reception power value Pr2. When the TX 100 receives a signal related to the second received power value Pr2 from the RX 200, the TX 100 calculates the power loss between the TX 100 and the RX 200. The power loss at this time is Pt2 - Pr2 (= Ploss2). A CP 1001 indicating the correspondence between Pt2 and Pr2 can be generated.

[0074] The TX 100 performs linear interpolation processing between CP 1000 and CP 1001 to generate a line segment 1002. Line segment 1002 represents the relationship between the transmitted power and the received power in a state where no foreign objects are present near the TX 100 and RX 200 (hereinafter referred to as the first detection state). Based on line segment 1002, the TX 100 can estimate the power value received by the RX 200 when the TX 100 transmits power at a predetermined transmitted power in the first detection state. For example, assume that the TX 100 transmits power at a third transmitted power value Pt3. In this case, the TX 100 can estimate the third received power value Pr3 received by the RX 200 based on point 1003 on line segment 1002 corresponding to Pt3.

[0075] As described above, the power loss between the TX 100 and RX 200 according to load can be obtained based on multiple combinations of the TX 100's transmitted power value and the RX 200's received power value, measured when the load changes. The power loss between the TX 100 and RX 200 according to all loads can be estimated through interpolation processing based on multiple combinations of the transmitted and received power values. In this way, the calibration process performed by the TX 100 and RX 200 to obtain combinations of transmitted and received power values ​​by the TX 100 is called a "calibration process using the power loss method." The calibration process is abbreviated as a CAL process. Performing the calibration process again to update or add calibration points after the calibration process has been performed once is called a recalibration process, abbreviated as a ReCAL process.

[0076] Assume the following situation: After CAL processing using the power loss method, TX 100 actually transmits power to RX 200 at the third transmitted power value Pt3, and TX 100 receives a signal related to received power value Pr3* from RX 200. The signal related to received power value Pr3* is a received power data packet (mode 0) predefined in the WPC standard. Alternatively, other messages may be used. Hereinafter, received power data packet (mode 0) is denoted by RP0. RP0 includes the value of received power value Pr3*. TX 100 calculates Pr3 - Pr3 by subtracting received power value Pr3* actually received from RX 200 from received power value Pr3 in the first detection state. * (= Ploss_FO). Ploss_FO can be estimated as the power consumed by the foreign object (ie, power loss) when the foreign object exists near the TX 100 and RX 200. Hereinafter, the state where the presence of the foreign object near the TX 100 and RX 200 is detected is referred to as the second detection state.

[0077] In the second detection state, the TX 100 compares the power loss Ploss_FO, which may be consumed by foreign matter, with a predetermined threshold. If the power loss Ploss_FO exceeds the threshold, the TX 100 can determine that a foreign matter is present. Alternatively, the TX 100 obtains the third received power value Pr3 from the RX 200 in the first detection state and pre-determines the power loss Pt3 - Pr3 (= Ploss3) between the TX 100 and RX 200.

[0078] Subsequently, the TX 100 acquires the received power value Pr3* from the RX 200 in the second detection state, and calculates the power loss Pt3 - Pr3 between the TX 100 and the RX 200 in the second detection state. * (= Ploss3 * ). Then, TX 100 can be * - Ploss3 to estimate the power loss Ploss_FO.

[0079] As described above, there are two methods of calculating Ploss_FO in the second detection state.

[0080] ●The first method is from Pr3 - Pr3 * Calculate Ploss_FO.

[0081] ●The second method is to use Ploss3 * - Ploss3 calculates Ploss_FO.

[0082] In this embodiment, the second method will be basically described; however, the contents of this embodiment are also applicable to the first method.

[0083] Next, we will refer to Figure 5A and Figure 5B Describes foreign body detection based on the quality factor measurement method predefined in the WPC standard. Figure 5A This is a schematic circuit diagram illustrating a method for measuring the quality factor (Q factor) using a quality factor measurement method. AC power supply 901 is a power source that outputs AC power generated by power transmission unit 103 of TX 100. Power transmission antenna 902 corresponds to power transmission antenna 105, and capacitor 903 corresponds to resonant capacitor 107. Power transmission antenna 902 and capacitor 903 are connected in series. Voltage value V8 is a voltage value having a predetermined frequency for operating the wireless power transmission system and generated by power transmission unit 103. Voltage value V9 is a voltage value applied to power transmission antenna 902. It is assumed here that TX 100 can change the frequency associated with the voltage value. Voltage values ​​V8 and V9 are voltage values ​​measured by TX 100 when transmitting an analog ping (hereinafter referred to as "AP") or a digital ping (hereinafter referred to as "DP") to RX 200. Since voltage values ​​V8 and V9 are AC voltage values, their effective mean square (RMS) values ​​can be used.

[0084] Figure 5BThe characteristic with a peak at 100 kHz is shown as an example of the V9 / V8 measurement results for frequency. The horizontal axis represents frequency, and the vertical axis represents the voltage ratio "V9 / V8." V9 / V8 represents the quality factor associated with the power transmitting antenna 902. Therefore, when an object is placed near the power transmitting antenna 902, the value of V9 / V8 changes. The change in quality factor varies depending on the case where no object is placed on the TX 100, the case where the RX 200 is placed on the TX 100, the case where a foreign object (such as a metal piece) is placed on the TX 100, and the case where both the RX 200 and the foreign object are placed on the TX 100.

[0085] During a negotiation phase (described later) predefined in the WPC standard, the TX 100 receives a signal indicating a FOD status packet from the RX 200. The FOD status packet includes a reference quality factor value and a reference resonant frequency value. The reference quality factor value is the quality factor that can be measured at the terminals of the power transmitting antenna of the test TX 100 when the RX 200 is placed on the test TX 100 and no foreign objects are nearby. The reference resonant frequency value is as follows. It is the resonant frequency calculated based on the inductance value that can be measured at the terminals of the power transmitting antenna of the test TX 100 when the RX 200 is placed on the test TX 100 and no foreign objects are nearby. Using a quality factor measurement method, a threshold is set with reference to the reference quality factor value. Foreign object detection is performed by comparing the threshold with the quality factor obtained from the actual V9 / V8 measurement. Alternatively, the threshold can be set with reference to the reference resonant frequency value. Foreign object detection is performed by comparing the threshold with the resonant frequency obtained from the actual V9 / V8 measurement.

[0086] The RX 200 and TX 100 of this embodiment perform communications for power transmission and reception control based on the WPC standard. The WPC standard predefines multiple phases, including a power transmission phase in which power transmission occurs and one or more phases prior to actual power transmission. Communications for power transmission and reception control required in each phase are performed. For example, based on a database acquired during the calibration phase, foreign object detection using a power loss method is performed during the power transmission phase. Foreign object detection using a quality factor measurement method is performed before power transmission (before transmitting a digital ping and during the negotiation or renegotiation phases).

[0087] The WPC standard includes the selection phase, the ping phase, and the configuration phase. In addition, the negotiation phase and the calibration phase are also provided. The following describes the processes in each phase.

[0088] During the selection phase, the TX 100 intermittently transmits a simulated ping to detect whether an object has been placed on the TX 100's charging base. A simulated 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 powered device. For example, it detects the placement of the RX 200 or a conductor sheet on the charging base. The TX 100 detects one or both of the voltage and current values ​​of the power transmitting antenna 105 during the simulated ping. When the voltage value falls below a threshold or the current value exceeds a threshold, the TX 100 determines that an object is present and transitions to the ping phase. Alternatively, when the quality factor calculated from the voltage value satisfies a predetermined condition, or when the quality factor calculated from the current value satisfies a predetermined condition, the TX 100 determines that an object is present and transitions to the ping phase.

[0089] During the Ping phase, the TX 100 transmits a digital Ping signal with higher power than the analog Ping signal. The digital Ping signal is a power signal used to activate the control unit of the RX 200 placed on the TX 100. The RX 200 notifies the TX 100 of the power receiving voltage value. In this way, the TX 100 receives a response from the RX 200 that has received the digital Ping signal, thereby recognizing that the object detected during the Selection phase is the RX 200. Upon receiving notification of the power receiving voltage value from the RX 200, the TX 100 transitions to the Configuration phase. Before the TX 100 transmits the digital Ping signal, the TX 100 measures the quality factor associated with the power transmitting antenna 105 using, for example, an analog Ping signal. The measurement results are used when performing foreign object detection processing using the quality factor measurement method. Depending on the version of the WPC standard, the Selection phase described above may be included as part of the Ping phase described above and may be referred to as the Ping phase.

[0090] During the configuration phase, TX 100 identifies RX 200 and obtains device configuration information (capability information) from RX 200. RX 200 transmits an ID packet and a configuration packet. The ID packet contains the identifier of RX 200, and the configuration packet contains the device configuration information (capability information) of RX 200. Having received the ID packet and the configuration packet, TX 100 returns an acknowledgement (ACK). The configuration phase then ends.

[0091] During the negotiation phase, the GP value is determined based on the GP value requested by the RX 200 and the power transmission capability of the TX 100. The TX 100 receives a FOD status packet from the RX 200, including a reference quality factor value and a reference resonant frequency value. In the quality factor measurement method, the presence of foreign matter is determined based on a threshold value set with reference to the reference quality factor value and the reference resonant frequency value. The TX 100 performs foreign matter detection processing using the quality factor measurement method in response to a request from the RX 200. The WPC standard predefines a method in which, after transitioning to the power transmission phase, similar processing to that performed during the negotiation phase is performed again in response to a request from the RX 200. The phase in which these processes are performed after transitioning from the power transmission phase is referred to as the renegotiation phase.

[0092] During the calibration phase, calibration processing using the power loss method is performed based on the WPC standard. The RX 200 notifies the TX 100 of a predetermined received power value, and the TX 100 makes adjustments for efficient power transmission. The predetermined received power value is, for example, the received power value in a light load state or a maximum load state (connected load state). The received power value notified to the TX 100 is used for foreign object detection processing using the power loss method.

[0093] During the power transmission phase, the TX 100 and RX 200 execute controls for starting and continuing power transmission, error handling, and stopping power transmission due to full charging. The TX 100 and RX 200 perform communication processing for these power transmission and reception controls. For example, using the power transmitting antenna 105 and the power receiving antenna 205 used when wireless power transmission is performed in accordance with the WPC standard, communication is performed by superimposing a signal on electromagnetic waves transmitted from the power transmitting antenna 105 or the power receiving antenna 205. The range within which communication between the TX 100 and RX 200 in accordance with the WPC standard is similar to the power transmission range of the TX 100. Depending on the version of the WPC standard, the calibration phase described above may also be referred to as the power transmission phase as part of the power transmission phase described above.

[0094] Next, we will refer to Figure 6 Describe the functions of the TX 100 control unit. Figure 6 This is a block diagram illustrating an example of the functional configuration of the control unit 101 of the power transmitting 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. The communication control unit 301 controls communication with the RX 200 based on the WPC standard via the first communication unit 104, or controls communication with the RX 200 via the second communication unit 109.

[0095] The power transmission control unit 302 controls the power transmission unit 103 to control power transmission to the RX 200. The measurement unit 303 measures a waveform attenuation index (described later). The measurement unit 303 measures the power to be transmitted to the RX 200 via the power transmission unit 103 and measures the average transmitted power per unit time. The measurement unit 303 also measures the quality factor associated with the power transmitting antenna 105. The measurement unit 303 measures the temperature using temperature sensors arranged at multiple locations on the TX 100. The measurement unit 303 also measures a quantity (e.g., coupling coefficient) indicating the state of electromagnetic coupling between the power transmitting antenna 105 and the power receiving antenna 205.

[0096] Using the above-described method, the setting unit 304 calculates and sets the threshold for foreign object detection in the quality factor measurement method and the threshold for foreign object detection in the power loss method. The setting unit 304 also sets the threshold for foreign object detection in the waveform attenuation method (described later). The setting unit 304 calculates and sets the threshold for foreign object detection or the threshold for detecting misalignment between the TX 100 and RX 200 based on, for example, the coupling coefficient between the power transmitting antenna 105 and the power receiving antenna 205 measured by the measurement unit 303. The setting unit 304 also calculates and sets the threshold for foreign object detection or the threshold for detecting misalignment between the TX 100 and RX 200 based on, for example, the temperature of the power transmitting device measured by the measurement unit 303.

[0097] The state detection unit 305 detects the state of the TX 100 and RX 200. For example, the state detection unit 305 detects the presence of foreign objects between the TX 100 and RX 200, and also detects misalignment between the power-transmitting antenna 105 and the power-receiving antenna 205. More specifically, the state detection unit 305 can perform state detection based on a power loss method, a quality factor measurement method, a waveform attenuation method, the temperature measured in the TX 100, and the electromagnetic coupling state (e.g., coupling coefficient) between the power-transmitting antenna 105 and the power-receiving antenna 205. The state detection unit 305 can also perform foreign object detection and misalignment detection between the power-transmitting antenna 105 and the power-receiving antenna 205 using other methods. For example, in a TX 100 that includes NFC communication capability, the state detection unit 305 performs state detection using a counterpart device detection function that complies with the NFC standard. In addition to detecting the presence of foreign objects and the electromagnetic coupling state between the power-transmitting antenna and the power-receiving antenna, the state detection unit 305 can also detect changes in the state of the TX 100. For example, the state detection section 305 may detect fluctuations in the number of RXs 200 on the TX 100 .

[0098] The setting unit 304 sets a threshold value used as a reference for determining the presence of foreign objects when the TX 100 performs status detection. Status detection may be based on, for example, a power loss method, a quality factor measurement method, a waveform attenuation method; status detection based on the temperature measured by the TX 100; or status detection based on, for example, the coupling coefficient between the power transmitting antenna 105 and the power receiving antenna 205. The setting unit 304 may use other methods to set the judgment threshold value required for status detection. The status detection unit 305 can perform foreign object detection and misalignment detection between the power transmitting antenna 105 and the power receiving antenna 205 based on the threshold value set by the setting unit 304 and the measurement results from the measurement unit 303. For example, the status detection unit 305 may obtain data such as a waveform attenuation index, transmitted power, a quality factor, the temperature measured by the TX 100, and the coupling coefficient between the power transmitting antenna 105 and the power receiving antenna 205 as the measurement results of the measurement unit 303.

[0099] Depend on Figure 6 The processes shown in the figure, performed by the communication control unit 301, the power transmission control unit 302, the measurement unit 303, the setting unit 304, and the state detection unit 305, can be implemented using programs executed by the CPU of the control unit 101, etc. While the programs are synchronized through event processing, etc., the respective processes are executed in parallel according to the corresponding procedures in the independent programs. However, two or more of these processes may be incorporated into the process executed by a single program.

[0100] Next, an example of the flow of processing related to power transmission and reception control performed by the TX 100 and the RX 200 will be described. Figure 7 This is a flowchart illustrating an example of a power transmission control process performed by the TX 100. This process is implemented, for example, by the TX 100 control unit 101 executing a program read from the memory 106. This process may be executed in response to the TX 100 being powered on, in response to a user of the TX 100 inputting an instruction to start a wireless power transmission application, or in response to the TX 100 being connected to a commercial power source and receiving power. This process may also be initiated at other times.

[0101] exist Figure 7 In S1201, the TX 100 performs the processing defined in the WPC standard as the selection phase and the ping phase, and waits for the placement of the RX 200. Specifically, the TX 100 repeatedly and intermittently transmits an analog ping signal in accordance with the WPC standard to detect the presence of an object within the power transmission range. For example, the TX 100 can detect the placement of the RX 200 or a conductive sheet on the charging base 300. When the TX 100 detects the presence of an object within the power transmission range, it transmits a digital ping signal.

[0102] When a predetermined response to the digital ping occurs, the TX 100 determines that the detected object is the RX 200 and that the RX 200 is placed on the charging base 300. Here, the "predetermined response" refers to a signal strength (SIG) data packet transmitted by the RX 200. This packet contains a signal strength value indicating the signal strength of the signal received by the RX 200. The signal strength value is calculated based on the following parameters: the voltage output by the rectifying section (rectifier) ​​of the power receiving unit 203 (rectifier output voltage) measured by the RX 200, the voltage of the open circuit including the power receiving antenna 205 (open circuit voltage) measured by the RX 200, or the received power value measured by the RX 200.

[0103] Before the TX 100 transmits the digital Ping, the TX 100 measures the quality factor related to the power transmitting antenna 105. The measurement result is used when performing a foreign matter detection process using the quality factor measurement method.

[0104] After detecting the placement of the RX 200, the TX 100 acquires identification information from the RX 200 in S1202 through communication during the configuration phase predefined in the WPC standard. During the configuration phase, the RX 200 transmits an identification packet (ID packet) to the TX 100. In addition to the manufacturer code and base device ID, which serve as identification information for each individual RX 200, the ID packet also stores information elements that can identify the supported version of the WPC standard.

[0105] In addition, the RX 200 transmits a configuration packet to the TX 100. The configuration packet includes the following capability information of the RX 200.

[0106] ● Maximum power value or reference power, which specifies the maximum power that the RX 200 can supply to the load

[0107] ●Information indicating whether the RX 200 has the WPC standard negotiation function

[0108] ●Parameters used in frequency shift keying, a communication modulation method used when the TX 100 transmits information to the RX 200

[0109] ●Information indicating whether the RX 200 supports out-of-band communication capability.

[0110] When TX 100 receives the above-mentioned packet from RX 200, TX 100 transmits a positive acknowledgement ACK to RX 200, and the configuration phase ends. TX 100 can obtain the identification information of RX 200 by using a method other than the communication during the configuration phase of the WPC standard. The identification information of each individual RX 200 can be a wireless power ID. Alternatively, the identification information can be any other identification information that can identify the individual RX 100, such as the Bluetooth address unique to the second communication unit 212 of the RX 200 (hereinafter referred to as "BD_ADDR"). BD_ADDR is an 8-byte address used in BLE. BD_ADDR is, for example, a public address predefined in the BLE standard that indicates the manufacturer of the RX 200 and the communication capabilities of BLE (second communication unit 212) for individual identification information. BD_ADDR can be a random address.

[0111] Subsequently, in S1203, TX 100 determines the GP through negotiation with RX 200 based on the request from RX 200 and its own power transmission capabilities. In S1203, communication occurs during the negotiation phase of the WPC standard. For example, RX 200 transmits a specific request to TX 100 to notify TX 100 of the requested power value. TX 100 determines whether to accept the request based on its own power transmission capabilities and other conditions. If TX 100 accepts the request, TX 100 transmits a positive acknowledgment (ACK) to RX 200. However, if TX 100 does not accept the request, TX 100 transmits a negative acknowledgment (NACK) or NAK to RX 200. If TX 100 accepts the request from RX 200, the GP value determined through negotiation with RX 200 is set as the value requested by RX 200. When the TX 100 does not accept the request from the RX 200, the GP value may be set to a predetermined value (e.g., 5 watts) specified in the WPC standard. When the TX 100 receives information indicating that the RX 200 does not support the negotiation phase (e.g., S1302 (described later)), the TX 100 does not communicate during the negotiation phase and sets the GP value to a predetermined value. The predetermined value is, for example, a value predefined in the WPC standard (e.g., 5 watts).

[0112] In response to a request from the RX 200, the TX 100 performs foreign object detection using the quality factor measurement method. The TX 100 receives a FOD status data packet from the RX 200. This packet contains the aforementioned reference quality factor value and reference resonant frequency value. The TX 100 then performs foreign object detection using the quality factor measurement method. Foreign object detection is performed based on the following information.

[0113] ●The quality factor and resonant frequency of the power transmitting antenna 105 measured before the TX 100 transmits the digital Ping

[0114] ● Thresholds of the reference quality factor value and the reference resonant frequency value received by the TX 100 from the RX 200

[0115] Subsequently, in S1204, the TX 100 and RX 200 perform the calibration phase (CAL process) in the WPC standard. During the calibration phase, the TX 100 performs the CAL process of the power loss method based on the determined reference power value or the determined GP value. Initially, the RX 200 transmits a signal containing information related to the received power in a light load state (hereinafter referred to as first reference received power information) to the TX 100. A light load state includes, for example, a load interruption state, a load state in which the received power value of the RX 200 is less than or equal to a first threshold, or a load state in which the received power value of the RX 200 falls within a predetermined range (hereinafter referred to as the "first range"). In this embodiment, the first reference received power information is assumed to be 500 milliwatts. The first reference received power information is information included in a received power data packet (mode 1) predefined in the WPC standard. Alternatively, other messages may be used. Hereinafter, the received power data packet (mode 1) is denoted by RP1. The TX 100 determines whether to accept the first reference received power information based on the control error value included in the control error (CE) packet received from the RX 200. If the TX accepts the first reference received power information, the TX 100 transmits an acknowledgement (ACK) to the RX 200. If the TX 100 does not accept the first reference received power information, the TX 100 transmits a negative acknowledgement (NAK) to the RX 200.

[0116] The RX 200 then performs processing for transmitting a signal containing information related to the received power in the connected load state (hereinafter referred to as second reference received power information) to the TX 100. The connected load state may be, for example, a maximum load state, a load state in which the transmitted power value is greater than or equal to a second threshold, or a load state in which the power received by the RX 200 is maximum power. Here, "maximum power" refers to power having a value close to the reference power. Alternatively, the connected load state is a load state in which the received power value of the RX 200 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. In this embodiment, the second reference received power information is assumed to be 15 watts. The second reference received power information is information contained in a received power data packet (mode 2) predefined in the WPC standard. Alternatively, other messages may be used.

[0117] Hereinafter, the received power data packet (mode 2) is denoted by RP2. The TX 100 determines whether to accept the second reference received power information based on the control error value contained in the control error (CE) data packet received from the RX 200. If the TX accepts the second reference received power information, the TX 100 transmits an acknowledgement (ACK) to the RX 200. If the TX 100 does not accept the second reference received power information, the TX 100 transmits a negative acknowledgement (NAK) to the RX 200. The TX 100 transmits an acknowledgement (ACK) in response to the second reference received power information from the RX 200, completing the CAL process.

[0118] As a result of the above-described CAL processing, the TX 100 is allowed to calculate the amount of power loss between the TX 100 and the RX 200 in both the light load state and the connected load state based on the TX 100's transmitted power value and the received power value included in the first reference received power information and the second reference received power message. The TX 100 can calculate the amount of power loss between the TX 100 and the RX 200 for all transmitted power levels available to the TX 100 by interpolating between multiple power loss levels. For example, the total transmitted power level available to the TX 100 refers to any power within the range of 500 milliwatts to 15 watts, which is the range of received power received by the RX 200 in this embodiment.

[0119] Then, in S1205, the TX 100 transmits power until the battery 207 of the RX 200 is fully charged. In S1205, communication during the power transfer phase in the WPC standard is performed. The RX 200 repeatedly transmits a control error (CE) data packet (hereinafter referred to as a "CE packet") to the TX 100 at intervals of t_interval. t_interval is a value defined in the WPC standard and is, for example, 250 milliseconds. The CE packet includes a request for an increase or decrease in the amount of transmitted power. The TX 100 adjusts the transmitted power by controlling the current or voltage of the power transmitting antenna 105 based on the received CE packet. In other words, the CE packet includes data related to parameters for adjusting the transmitted power. By repeating this process, power is transmitted at an appropriate level in accordance with the request from the RX 200 in substantially real time.

[0120] When the battery 207 is fully charged, the RX 200 transmits an end-of-power-transfer packet (hereinafter referred to as an "EPT packet") to end the power transfer phase. The RX 200 may transmit an EPT packet for reasons other than fully charging. When the power transfer phase ends, the TX 100 stops sending power to charge the RX 200.

[0121] When the TX 100 does not receive the next CE packet after a period of time t_timeout has passed since the last CE packet was received, the TX 100 determines that the RX 200 has been removed from the charging base 300. In this case, the power transfer phase ends. t_timeout is a value defined in the WPC standard and is, for example, 1500 milliseconds.

[0122] During the power transfer phase, RX 200 may transmit packets other than CE packets to TX 100. For example, there is a charge status data packet that notifies TX 100 of the status of RX 200's battery 207. This packet stores a charge status value indicating the percentage of charge of battery 207. When TX 100 receives the charge status data packet, it notifies the user of the charge status by, for example, displaying characters or graphics based on the charge status value through UI unit 110. TX 100 can receive the charge status data packet at any time and notify the user at any timing.

[0123] During the power transmission phase, the TX 100 transmits power to the RX 200 while executing a foreign object detection process using a power loss method. For example, through CAL processing, the amount of power loss between the TX 100 and RX 200 in the first detection state during the power transmission process is calculated based on the difference between the transmitted and received power values. The calculated power loss corresponds to a reference power loss amount in the absence of foreign objects. The TX 100 then determines that the difference between the power loss amount between the TX 100 and RX 200 measured during power transmission after the CAL process and the reference power loss amount is greater than or equal to a threshold value, and the TX 100 determines the detection state to be the second detection state.

[0124] Will refer to Figure 8 This section describes an example of the flow of processing related to power reception control performed by the RX 200. This processing is implemented, for example, by the RX 200 control unit 201 executing a program read from the memory 208. In S1301, the RX 200 executes processing defined as the selection phase and the ping phase in the WPC standard, and waits for its own device to be placed on the TX 100. For example, the RX 200 detects its placement on the TX 100 by detecting a digital ping from the TX 100.

[0125] When the RX 200 detects that its own device is placed on the TX 100, in S1302, the RX 200 transmits a signal including its own device's identification information to the TX 100 using an ID packet and a configuration data packet. The identification information of the RX 200 may be transmitted using methods other than the communication during the configuration phase in the WPC standard. Any other identification information, such as BD_ADDR, may be used as long as it can identify each individual RX 200. In S1302, the RX 200 may transmit information other than the identification information to the TX 100.

[0126] Subsequently, at S1303, the RX 200 transmits a signal including information regarding the power value requested from the TX 100 and negotiates with the TX 100 to determine the GP. At S1303, communication during the negotiation phase of the WPC standard occurs. The RX 200 transmits a FOD status data packet to the TX 100. This packet contains a reference quality factor value and a reference resonant frequency value.

[0127] Subsequently, in S1304, the RX 200 and TX 100 perform the calibration phase (CAL process) in the WPC standard. The RX 200 performs the following process during this phase. Subsequently, in S1305, the RX 200 receives power until the battery 207 is fully charged. The RX 200 performs the following process during this phase. During the power transfer phase, the RX 200 and TX 100 perform a foreign object detection process using the power loss method. In S1305, the RX 200 repeatedly transmits CE packets at intervals of t_interval and eventually transmits an EPT packet to the TX 100 to terminate this process.

[0128] As described above, the power loss method performs foreign object detection based on the results of measuring power loss during power transmission from the TX 100 to the RX 200. This method has the disadvantage of decreasing foreign object detection accuracy when the TX 100 is transmitting high power. However, it has the advantage of being able to perform foreign object detection while power transmission is ongoing, thus maintaining high power transmission efficiency.

[0129] Incidentally, foreign object detection using only the power loss method during the power transmission phase can lead to false detection of foreign objects and the possibility of incorrectly determining their absence despite their presence. For example, assume that a foreign object is present near the TX 100 and RX 200 during power transmission during the power transmission phase. In this case, there is a possibility that heat generation from the foreign object may increase, so it is desirable to improve the accuracy of foreign object detection during the power transmission phase. Therefore, a foreign object detection method using a waveform attenuation method will be described. Using this method, the TX 100 can perform foreign object detection based on the attenuation state of the power transmission waveform (voltage waveform or current waveform) related to power transmission to the RX 200. In other words, foreign object detection can be performed without using a newly defined foreign object detection signal or the like.

[0130] Figure 9 : is a diagram showing the principle of foreign object detection using a waveform attenuation method. It shows an example of foreign object detection using a power transmission waveform related to power transmission from the power transmitting device 100 to the power receiving device 200. Figure 9 , the horizontal axis represents time, and the vertical axis represents voltage value or current value. Figure 9 Waveform 600 shows, for example, the change over time in the voltage value of the high-frequency voltage applied to power transmitting antenna 105 of TX 100. TX 100, which is transmitting power to RX 200 via power transmitting antenna 105, stops power transmission at time T0. At time T0, the power supply from power supply unit 102 stops, and the power supply to power transmitting antenna 105 stops. The frequency f1 of the power transmission waveform before power transmission stops at time T0 is a fixed frequency (e.g., between 87 kHz and 205 kHz used in the WPC standard). Point 601 on waveform 600 is on the envelope of the high-frequency voltage and corresponds to voltage value A1 at time T1. At point 601, (T1, A1) indicates that the voltage value at time T1 is A1. Point 602 on waveform 600 is on the envelope of the high-frequency voltage and corresponds to voltage value A2 at time T2. At point 602 , (T2, A2) indicates that the voltage value at time T2 is A2.

[0131] The quality factor (Q factor) associated with the power transmitting antenna 105 can be obtained based on the temporal change in the voltage value from time T0. TX calculates the quality factor using equation (1) based on, for example, the time and voltage values ​​at points 601 and 602 on the envelope of the high-frequency voltage and the frequency f2 of the high-frequency voltage after power transmission is stopped at time T0.

[0132] (Formula 1)

[0133] In Formula 1, ln represents a natural logarithm function.

[0134] The frequency ( f1 ) of the power transmission waveform when the TX 100 is transmitting power to the RX 200 and the frequency ( f2 ) of the power transmission waveform when the TX 100 has stopped transmitting power to the RX 200 may be different from each other.

[0135] When there is a foreign object near TX 100 and RX 200, the value of the quality factor decreases. This is because energy loss occurs due to the foreign object. Therefore, focusing on the slope of the attenuation of the voltage value, the slope of the straight line connecting point 601 and point 602 is greater when a foreign object is present than when no foreign object is present. When energy loss occurs due to a foreign object, the attenuation factor of the amplitude of waveform 600 increases. For example, the waveform attenuation method can determine the presence or absence of a foreign object based on the attenuation state of the voltage value between point 601 and point 602. When actually determining the presence or absence of a foreign object, the judgment can be made by comparing the numerical value indicating the attenuation state. For example, when making a judgment by using the quality factor, a decrease in the value of the quality factor below the reference value means that the waveform attenuation factor (the degree of reduction in the amplitude of the waveform per unit time) increases.

[0136] In another example, there is a method of making a judgment using the slope of the straight line connecting points 601 and 602 calculated from (A1 - A2) / (T2 - T1). When the time (T1 and T2) for measuring the decay state of the voltage value is fixed, the presence or absence of foreign matter can be judged by using the difference in voltage values ​​(A1 - A2) or the ratio of voltage values ​​(A1 / A2). Alternatively, when the voltage value A1 immediately after the power supply is stopped is constant, the presence or absence of foreign matter can be judged by using the voltage A2 after a predetermined time has passed. Alternatively, the presence or absence of foreign matter can be judged by using the time (T2 - T1) that elapses until the voltage value A1 reaches the predetermined voltage value A2.

[0137] In the waveform attenuation method, the presence of foreign matter can be determined based on the attenuation state of the waveform during the power transmission stop period. In this embodiment, indices representing the attenuation state such as the quality factor are collectively referred to as "waveform attenuation indices." Figure 9 The vertical axis of has been described as the axis of the voltage value of the high-frequency voltage applied to the power transmitting antenna 105 of the TX 100; however, Figure 9The vertical axis can also represent the current value flowing through the power transmitting antenna 105. As with the voltage value, the attenuation state of the current value during the power transmission suspension period changes depending on the presence or absence of foreign matter. The waveform attenuation factor is higher when a foreign object is present than when no foreign matter is present. Therefore, foreign matter can be detected by applying a similar method to the temporal change in the current value flowing through the power transmitting antenna 105. In other words, foreign matter detection can be performed by determining the presence or absence of foreign matter using a quality factor calculated from the current waveform, the slope of the current value attenuation, the difference in current values, the ratio of current values, the absolute value of the current values, or the time period until the current value reaches a predetermined value as a waveform attenuation indicator.

[0138] There are methods based on both the attenuation state of voltage values ​​and the attenuation state of current values. Using this method, the presence of foreign matter can be determined using evaluation values ​​calculated from the waveform attenuation index of the voltage and current values. This configuration is not limited to measuring the waveform attenuation index during the period when the TX 100 temporarily stops power transmission. The waveform attenuation index can be measured during the period when the TX 100 temporarily reduces the power supplied from the power supply unit 102 from a predetermined power level to a power level lower than the predetermined power level. In other words, the waveform attenuation index can be measured during the period when the power supply for power transmission to the power transmitting antenna 105 temporarily reduces from a predetermined power level to a power level lower than the predetermined power level. The power transmission unit 103 can perform the aforementioned restriction or suspension of power transmission to the power transmitting antenna 105 based on a command signal from the control unit 101. In the above example, the voltage or current values ​​are measured at two points in time during the period when the TX 100 limits power transmission. Alternatively, the voltage or current values ​​can be measured at three or more points in time.

[0139] Will refer to Figure 10 A foreign object detection method based on a power transmission waveform using a waveform attenuation method is described. Figure 10 The power transmission waveform shown is a power transmission waveform when foreign object detection is performed using a waveform attenuation method. The horizontal axis represents time, and the vertical axis represents the voltage value or current value of the power transmission antenna 105.

[0140] During the transient response period immediately after the TX 100 starts power transmission, the power transmission waveform is unstable. Therefore, during the transient response period, the RX 200 is controlled not to communicate with the TX 100 (communication via amplitude modulation or load modulation). The TX 100 is controlled not to communicate with the RX 200 (communication via frequency shift keying). Hereinafter, this period is referred to as the communication disabled period. However, during the communication disabled period, the TX 100 transmits power to the RX 200. Then, after the communication disabled period has passed, the TX 100 transmits power to the RX 200. Hereinafter, this period is referred to as the power transmission period. When the TX 100 has received a foreign object detection execution request (packet, command) from the RX 200, the TX 100 temporarily stops power transmission or temporarily reduces the power transmission after a predetermined period of time. Hereinafter, this predetermined period of time is referred to as the preparation period. During the preparation period, the RX 200 is controlled not to communicate with the TX 100 (communication using amplitude modulation, load modulation, or backscatter modulation). The TX 100 is also controlled not to communicate with the RX 200 using frequency shift keying. By controlling not to communicate during the preparation period, disturbances in the power transmission waveform are suppressed, and the TX 100 can calculate a waveform attenuation index of the power transmission waveform (described later) with higher accuracy.

[0141] The foreign object detection execution request (packet, command) described above can be RP0, RP1, or RP2. When the TX 100 receives the foreign object detection execution request, the power transmission unit 103 of the TX 100 temporarily stops power transmission or temporarily reduces the transmitted power, resulting in the amplitude of the transmitted power waveform attenuating. The period from the time when the TX 100 temporarily stops power transmission or the time when the TX 100 temporarily reduces the transmitted power to the time when the TX 100 resumes power transmission or the time when the TX 100 begins to restore the transmitted power is called the power transmission control period.

[0142] Here, "resumption of power transmission" means that the TX 100 increases the transmitted power to a predetermined value. Alternatively, the period from when the TX 100 temporarily sets the value of the inverter input voltage input to the inverter of the power transmission unit 103 to zero volts or temporarily reduces the value of the inverter input voltage to when the TX 100 returns the value of the input voltage to a predetermined value is hereinafter referred to as the power transmission power control period. Alternatively, the period from when the TX 100 temporarily sets the value of the inverter output voltage output by the inverter of the power transmission unit 103 to zero volts or temporarily reduces the value of the inverter output voltage to when the TX 100 returns the value of the output voltage to a predetermined value is hereinafter referred to as the power transmission power control period. The TX 100's control of temporarily stopping or temporarily reducing the transmitted power is referred to as power transmission power control. The TX 100 calculates a waveform attenuation index based on the attenuation waveform and compares the calculated waveform attenuation index with a predetermined threshold value to determine the presence or absence of foreign matter or the likelihood (existence probability) of foreign matter (hereinafter referred to as foreign matter determination). During the transmission power control period, the RX 200 is controlled not to communicate with the TX 100 using amplitude modulation, load modulation, or backscatter modulation. The TX 100 is also controlled not to communicate with the RX 200 using frequency shift keying. By controlling not to communicate during the transmission power control period, disturbances in the transmission waveform are suppressed, allowing the TX 100 to calculate the waveform attenuation index of the transmission waveform with higher accuracy. Foreign object detection can be performed during the transmission power control period, the communication disabled period, or the transmission period.

[0143] After the transmission power control period has elapsed, if no foreign object is detected, the TX 100 controls the resumption of power transmission or the restoration of transmitted power. Because the power transmission waveform is unstable during the transient response period immediately after control starts, this period becomes a communication disabled period. This period then transitions to a power transmission period, during which the TX 100 stably transmits power to the RX 200.

[0144] As described above, the TX 100 repeatedly performs control at or during the power transmission start, communication disabled period, power transmission period, preparation period, and power transmission power control period. The TX 100 calculates a waveform attenuation index based on the attenuated waveform at predetermined timing and performs foreign object detection based on the comparison result between the calculated waveform attenuation index and a predetermined threshold value. In other words, foreign object detection can be performed based on voltage or current values ​​at two or more time points during a predetermined period of time when power transmission is restricted (including power transmission suspension). During the preparation period, power transmission power control period, and communication disabled period, the RX 200 is controlled so as not to communicate with the TX 100 using amplitude modulation, load modulation, or backscatter modulation. The TX 100 is also controlled so as not to communicate with the RX 200 using frequency shift keying. In other words, the TX 100 is controlled so as not to communicate with the RX 200 for a predetermined first period after receiving an execution request (packet, command) from the RX 200. In the WPC standard, a period during the power transfer phase during which the TX 100 cannot transmit a packet to the RX 200 after receiving a packet other than an execution request (packet, command) from the RX 200 is predefined. The first period is longer than this period.

[0145] The RX 200 is controlled not to communicate with the TX 100 for a predetermined second period after transmitting an execution request (packet, command) to the TX 100. The WPC standard predefines a period during which the RX 200 cannot transmit a packet to the TX 100 after transmitting a packet other than an execution request (packet, command) to the TX 100 during the power transfer phase. The second period is longer than this period.

[0146] Incidentally, during the transmission power control period, when components such as the receiving power unit 203, the charging unit 206, and the battery 207 are connected to the receiving antenna 205 and the resonant capacitor 211 of the RX 200, the waveform attenuation index is affected by the load on these components. In other words, the value of the waveform attenuation index changes depending on the status of the receiving power unit 203, the charging unit 206, and the battery 207. As a result, even when the value of the waveform attenuation index is large, it is difficult to distinguish between the influence of foreign matter and the influence of changes in the status of the receiving power unit 203, the charging unit 206, and the battery 207. Therefore, when performing foreign matter detection by measuring the waveform attenuation index, the control unit 201 of the RX 200 opens the first switch unit 209 during the preparation period. The RX 200 transmits an execution request (packet, command) to the TX 100 and performs the above-mentioned processing during the preparation period. Alternatively, the RX 200 transmits an execution request (packet, command) to the TX 100 and simultaneously performs the above-mentioned processing. Therefore, the influence of the battery 207 can be reduced. A similar advantageous effect can be achieved by establishing a light load state instead of interrupting first switching unit 209. A similar advantageous effect can be achieved by RX 200 performing load control so that the received power is the minimum power, instead of interrupting first switching unit 209. Alternatively, a similar advantageous effect can be achieved by RX 200 performing load control so that the received power is within a predetermined range or below or equal to a predetermined threshold, instead of interrupting first switching unit 209. Here, in the context of "power within a predetermined range" or "power below or equal to a predetermined threshold," "power" refers to power that is approximately 10% of the reference power. Alternatively, RX 200 can control the load so that a predetermined power is supplied to the load, instead of interrupting first switching unit 209. This can be achieved by controlling first switching unit 209. RX 200 also maintains this control during the power transmission control period. Then, at a timing after power transmission is resumed, this control is canceled, and the state is controlled to return to the original state.

[0147] Alternatively, the control unit 201 turns on the second switch unit 210 to short-circuit the circuit, establishing a state where current flows through a closed loop consisting of the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210. This reduces the influence of the power receiving unit 203, the charging unit 206, and the battery 207. The RX 200 transmits a foreign object detection execution request (command) to the TX 100 and performs the above-described processing during the preparation period. Alternatively, the RX 200 transmits an execution request (packet, command) to the TX 100 while simultaneously performing the above-described processing. The RX 200 also maintains the above-described control during the power transmission control period. Then, at a timing after power transmission is resumed, the above-described control is canceled, and the state is controlled to return to the original state. By acquiring a waveform attenuation index based on the power transmission waveform measured when the first switch unit 209 is interrupted or when the second switch unit 210 is turned on to short-circuit (establish a connection), more accurate foreign object detection can be achieved. Alternatively, by both interrupting the first switching unit 209 and short-circuiting (connecting) the second switching unit 210 , even higher-precision foreign matter detection can be performed.

[0148] Alternatively, the RX 200 can control the system to transition to low power consumption mode or maintain constant power consumption during a preparation period, with the first switch unit 209 closed to short-circuit and the second switch unit 210 open to interrupt power. The RX 200 transmits an execution request (packet, command) to the TX 100 and performs the aforementioned processing during the preparation period. Alternatively, the RX 200 transmits an execution request (packet, command) to the TX 100 while simultaneously performing the aforementioned processing. The RX 200 also maintains the aforementioned control during the power transmission control period. Then, at a timing after power transmission is resumed, the aforementioned control is canceled, and the system is controlled to return to its original state. When power consumption in the RX 200 is not constant or when high power is consumed, the value of the waveform attenuation index based on the attenuation waveform is affected by fluctuations in power consumption. To reduce this impact, it is effective to limit or stop the operation of software applications running on the RX 200, or to set the hardware functional blocks of the RX 200 to low power consumption mode or an operation stop mode. By using a waveform attenuation index based on the power transmission waveform measured while the RX 200's power consumption is suppressed for foreign object detection, even more accurate foreign object detection is possible.

[0149] Similarly, in the TX 100, when measuring the waveform attenuation index, if components such as the power transmission unit 103, the first communication unit 104, and the power supply unit 102 are connected to the power transmission antenna 105 and the resonant capacitor 107 of the TX 100, the waveform attenuation factor is affected by these components. In other words, the value of the waveform attenuation index changes depending on the status of the power transmission unit 103, the first communication unit 104, and the power supply unit 102. As a result, even when the value of the waveform attenuation index is large, for example, it is difficult to distinguish between the influence of foreign matter and the influence of the power transmission unit 103, the first communication unit 104, and the power supply unit 102.

[0150] Therefore, when the TX 100 receives a foreign object detection execution request (command) from the RX 200, the control unit 101 turns on the switch unit 108 during the preparation period. This results in a state in which current flows through a closed loop circuit formed by the power-transmitting antenna 105, the resonant capacitor 107, and the switch unit 108. Consequently, when measuring the waveform attenuation index in the TX 100, the influence of the power-transmitting unit 103, the first communication unit 104, and the power supply unit 102 can be reduced.

[0151] Alternatively, the influence of the power supply unit 102, the power transmission unit 103, and the first communication unit 104 can be reduced by providing a switch (not shown) between the power transmission antenna 105 and the power transmission unit 103 and interrupting this switch during the preparation period. Alternatively, a switch can be provided between the power transmission unit 103 and the closed-loop circuit formed by the power transmission antenna 105, the resonant capacitor 107, and the switch unit 108. When the TX 100 measures the waveform attenuation index for foreign object detection, the TX 100 can reduce the aforementioned influence by interrupting the closed-loop circuit and the power transmission unit through control of the switch. The TX 100 also maintains this control during the power transmission control period. Then, at the timing after power transmission is resumed, this control is canceled, and the state is controlled to return to the original state. By performing these methods individually or in combination, more accurate foreign object detection can be achieved.

[0152] As described above, at least one or more of the following is achieved: a short-circuit (connected) state in which the switch unit 108 is turned on; an interruption state established by a switch associated with the power-transmitting antenna 105 and the power-transmitting unit 103; and an interruption state established by a switch associated with the closed-loop circuit and the power-transmitting unit 103. This configuration enables higher-precision foreign object detection.

[0153] Next, we will describe a method for setting a threshold for the waveform attenuation index used for state detection and foreign object determination in the TX 100 and RX 200 using the waveform attenuation method. The measured value of the waveform attenuation index can be compared with a predetermined threshold, and foreign object determination can be made based on the comparison result. A first threshold setting method involves the TX 100 maintaining a threshold (i.e., the predetermined value is a common value independent of the RX 200 to which power is transmitted). The threshold can be a fixed value or a variable value determined by the TX 100 based on the circumstances. When a foreign object is present, the power transmission waveform during the transmission power control period has a high waveform attenuation factor. Therefore, the value of the waveform attenuation index acquired in the absence of a foreign object is maintained and set as the threshold. By comparing the measured value of the waveform attenuation index with the threshold, it can be determined that "a foreign object is present" or "the possibility of a foreign object being present is high." For example, when using the quality factor as the waveform attenuation indicator, the TX 100 compares the measured value of the quality factor with a predetermined threshold. The threshold is set based on the measured value in the first detection state or a value obtained by adding a measurement error to the measured value. When the quality factor is less than the threshold, it is determined that "foreign matter is present" or "the possibility of foreign matter is high." When the quality factor is greater than or equal to the threshold, it is determined that "foreign matter is not present" or "the possibility of foreign matter is low."

[0154] The second threshold setting method involves the TX 100 adjusting and determining the threshold based on information transmitted from the RX 200. It should be noted that this differs from the first threshold setting method in that the value of the waveform attenuation index may vary depending on the RX 200 to which power is transmitted and placed. This is because the electrical characteristics of the RX 200, coupled via the TX 100's power transmission antenna, influence the value of the waveform attenuation index. For example, when using the quality factor as the waveform attenuation indicator, the quality factor measured by the TX 100 when no foreign matter is present may vary depending on the RX 200 placed on the TX 100. Therefore, the RX 200 maintains quality factor information for each TX 100 when mounted on the TX 100 without foreign matter present, and notifies the TX 100 of this quality factor information. The TX 100 then adjusts and determines the threshold for each RX 200 based on the quality factor information received from the RX 200.

[0155] More specifically, during the negotiation phase, TX 100 receives a FOD status packet containing information related to a reference quality factor value, and adjusts and determines a threshold value in the quality factor measurement method. The reference quality factor value is a quality factor that can be measured at the terminal of the power transmitting antenna of the test TX 200 when the RX 200 is placed on the test TX 100 and no foreign matter is present nearby. TX 100 assumes that the reference quality factor value corresponds to "quality factor information when the RX 200 is placed on the TX 100 in a state where no foreign matter is present," and uses this value to determine the threshold value. In other words, TX 100 can adjust and determine the threshold value for foreign matter judgment using the waveform attenuation method based on the reference quality factor value. During the negotiation phase, the reference quality factor value transmitted from RX 200 to TX 100 is information for foreign matter detection using a quality factor measurement method that originally measures the quality factor in the frequency domain. However, when using the quality factor as a waveform attenuation indicator, although the method of deriving the quality factor is different, it is possible to utilize Equation 1 from, for example, by using a waveform attenuation method that measures the quality factor in the time domain. Figure 9 The quality factor is obtained by measuring the waveform. Therefore, the threshold value of the quality factor in the waveform attenuation method can be set based on the reference quality factor value. The value of the waveform attenuation index obtained by adding a predetermined value (a value corresponding to the measurement error) to the reference quality factor value can be set as the threshold for foreign matter judgment.

[0156] In this way, when the TX 100 sets the threshold value of the quality factor in the waveform attenuation method based on the information transmitted from the RX 200 to the TX 100 during the negotiation phase, no processing such as new measurement for setting the threshold value is required. As a result, the threshold value can be set in a shorter period of time.

[0157] The third threshold setting method involves the TX 100 measuring the waveform attenuation index in the absence of foreign matter and then adjusting and determining the threshold based on information related to the measurement results. The following describes the timing for pre-measuring the waveform attenuation index in the absence of foreign matter. During the negotiation phase in the WPC standard, if foreign matter detection using the quality factor measurement method is performed and the result indicates the absence of foreign matter, the phase proceeds to the calibration phase and the power transmission phase. In other words, the fact that the phase has progressed to the negotiation phase and subsequent phases means that the foreign matter detection using the quality factor measurement method has determined the absence of foreign matter. There is a high probability that the waveform attenuation index can be measured in the absence of foreign matter during any of the negotiation phase, calibration phase, and power transmission phase. Therefore, the timing for measuring the waveform attenuation index in the absence of foreign matter can be any of the negotiation phase, calibration phase, and power transmission phase.

[0158] For example, let's assume the case of measuring the waveform attenuation index during the power transmission phase. The timing for measuring the waveform attenuation index in the absence of foreign matter is set at the initial stage of the power transmission phase. The reason for this is that the probability of foreign matter entering the vicinity of TX 100 and RX 200 increases as the time elapses from the point in time when the quality factor measurement method determines the absence of foreign matter. The timing is specified by either RX 200 or TX 100, and TX 100 measures the waveform attenuation index at that time and sets the value of the waveform attenuation index as a threshold. When RX 200 specifies the timing, RX 200 transmits a predetermined packet to TX 100 to notify TX 100 of the timing. When TX 100 specifies the timing, TX 100 transmits a predetermined packet to RX 200 to notify RX 200 of the timing. The value obtained by adding a predetermined value (a value corresponding to the measurement error) to the waveform attenuation index can be set as the threshold for foreign matter determination.

[0159] The fourth threshold setting method involves the TX 100 adjusting and determining the threshold value based on the transmitted power. The waveform attenuation index value may vary depending on the transmitted power of the TX 100. This is because heat generation and various circuit characteristics of the TX 100 vary depending on the level of transmitted power, and these factors affect the waveform attenuation index value. The TX 100 measures the waveform attenuation index for each transmitted power level and adjusts and determines the threshold value based on the measurement results, resulting in more accurate foreign object detection.

[0160] Figure 11 1 is a diagram for illustrating a method of setting a threshold value for foreign object determination for each transmitted power of the TX 100 in the waveform attenuation method. Figure 11 In the graph, the horizontal axis represents the transmitted power of the TX 100, and the vertical axis represents the waveform attenuation index (waveform attenuation factor) of the voltage waveform or current waveform. On the graph line represented by a straight line segment 1102, point 1100 corresponds to the transmitted power value Pt1 and the waveform attenuation index δ1, and point 1101 corresponds to the transmitted power value Pt2 and the waveform attenuation index δ2. On the graph line, point 1103 corresponds to the transmitted power value Pt3 and the waveform attenuation index δ3.

[0161] Initially, when power is transmitted from the TX 100, the RX 200 is controlled to enter a light load state. In this light load state, no power is supplied to the load of the RX 200, or only power below a threshold is supplied, or power within a predetermined range (hereinafter referred to as the "third range") is supplied. Assume that the transmitted power value of the TX 100 in this state is Pt1. The RX 200 then transmits a packet requesting measurement of a waveform attenuation index to the TX 100. Upon receiving this packet, the TX 100 stops power transmission or reduces the transmitted power while the load of the RX 200 is controlled to a light load state, in order to measure the waveform attenuation index δ1. At this point, the TX 100 identifies the transmitted power value Pt1 and stores a calibration point 1100 in memory, where CP 1100 is a calibration point that associates the transmitted power value Pt1 with the waveform attenuation index δ1. The RX 200 then executes control in the connected load state. The connected load state refers to a state in which, when power is transmitted from the TX 100, maximum power is supplied to the load on the RX 200, power is supplied that is greater than or equal to a predetermined threshold, or power is supplied within a predetermined range (hereinafter referred to as the "fourth range"). Here, the "fourth range" is a power range higher than the "third range." Assume that the transmitted power value of the TX 100 in this state is Pt2. The RX 200 then transmits a packet requesting measurement of a waveform attenuation index to the TX 100. Upon receiving this packet, the TX 100 stops power transmission or reduces the transmitted power while the load on the RX 200 is controlled to the connected load state, in order to measure the waveform attenuation index δ2. At this point, the TX 100 stores a CP 1101 in memory, where the CP 1101 associates the transmitted power value Pt2 with the waveform attenuation index δ2. The TX 100 then performs linear interpolation between the CPs 1100 and 1101 to generate a line segment 1102. Line segment 1102 represents the relationship between the transmitted power in the first detection state, when no foreign objects are present around the TX 100 and RX 200, and the waveform attenuation index of the waveform observed at the power transmitting antenna 105. Therefore, based on line segment 1102, the TX 100 can estimate the waveform attenuation index of the waveform observed at the power transmitting antenna 105 for each transmitted power value in the first detection state. For example, when the transmitted power value is Pt3, the waveform attenuation index is estimated as δ3 based on point 1103 corresponding to Pt3 on line segment 1102. Based on the estimation results, the TX 100 can calculate a threshold value for determining the presence of a foreign object for each transmitted power value. For example, a waveform attenuation index that is greater than the estimated waveform attenuation index in the first detection state for the transmitted power value by a predetermined value (a value corresponding to the measurement error) can be set as the threshold for determining foreign objects.

[0162] The CAL process performed by the TX 100 and RX 200, in which the TX 100 acquires a combination of a transmitted power value and a waveform attenuation index, is referred to below as "CAL process using the waveform attenuation method." Performing the calibration process again to update or add calibration points after performing the calibration process once is referred to as recalibration, abbreviated as ReCAL. In the above example, two transmitted power values, Pt1 and Pt2, are measured. For higher accuracy, the waveform attenuation index for each transmitted power can be calculated by measuring at three or more points. After notifying the TX 100 of the execution of the control via a predetermined packet, the RX 200 can execute either the light load control or the connected load control. Either of these two control methods can be executed first.

[0163] The operation of calculating the threshold value for foreign object judgment for each load (or each transmitted power value) described in this embodiment can be performed during the calibration phase. As described above, the TX 100 acquires the data required when performing foreign object detection using the power loss method during the calibration phase. At this time, when the load state of the RX 200 is the light load state, the TX 100 acquires data related to the received power value and power loss of the RX 200, and when the load state is the connected load state, the TX 100 acquires data related to the received power value and power loss of the RX 100. Therefore, during the calibration phase, when the RX 200 enters the light load state or when the RX 200 enters the connected load state, Figure 11 Measurements at CP 1100 and CP 1101 in the RX 200 can be performed simultaneously with power loss measurements. For example, when TX 100 receives a signal with first baseline power information from RX 200, in addition to the predetermined processing performed during the calibration phase, TX 100 also measures CP 1100. The first baseline power information is information related to RP1 predefined in the WPC standard. Alternatively, other messages can be used. When TX 100 receives a signal with second baseline power information from RX 200, in addition to the predetermined processing performed during the calibration phase, TX 100 also measures CP 1101. The second baseline power information is information related to RP2 predefined in the WPC standard. Alternatively, other messages can be used. There is no need to set separate time periods for measuring CP 1100 and CP 1101, so CP 1100 and CP 1101 can be measured in a shorter time period.

[0164] In this way, the TX 100 adjusts and sets thresholds for waveform attenuation indicators for each transmitted power based on information about the waveform attenuation indicator measured by the TX 100 at the transmitted power. For example, when using the quality factor as the waveform attenuation indicator, the TX 100 compares the measured quality factor value with the threshold value determined using the above-described method. If the measured quality factor value is less than the threshold value, it is determined that "foreign matter is present" or "there is a possibility of foreign matter being present." If the measured quality factor value is greater than or equal to the threshold value, it is determined that "foreign matter is not present" or "the possibility of foreign matter being present is low." This configuration, by setting thresholds for each transmitted power level of the TX 100, enables more accurate foreign matter detection.

[0165] The number of thresholds for foreign matter determination set using the above method is not limited to one. Multiple thresholds can be set in a stepwise manner. For example, the first threshold can be set as the threshold for determining "the presence of an abnormal state," the second threshold can be set as the threshold for determining "the likelihood of an abnormal state is high," the third threshold can be set as the threshold for determining "the likelihood of an abnormal state is low," and the fourth threshold can be set as the threshold for determining "the absence of an abnormal state."

[0166] There's a possibility that accuracy cannot be guaranteed by executing foreign object detection processing only once. For example, when performing a single transmission power control during foreign object detection using a waveform attenuation method and determining foreign object detection based on the waveform attenuation index at that time, there's a possibility that the amplitude and phase of the power transmission waveform during the transmission power control period may be disturbed. This can be due to noise contamination during the transmission power control period or misalignment of the RX 200 placed on the TX 100. In such cases, if the waveform attenuation index value obtained from the power transmission waveform during the single transmission power control period is inaccurate, there's a possibility of misjudgment in foreign object detection. Therefore, the TX 100 can execute transmission power control multiple times, measure the waveform attenuation index from the power transmission waveform during the multiple transmission power control periods, and perform more accurate foreign object detection based on the multiple measurement results.

[0167] Next, we will describe a first measurement method as a method for measuring the coupling state indicator for the power-transmitting and power-receiving antennas. The measurement performed in the first measurement method is referred to as the first measurement. In wireless power transmission, power is transmitted while the power-transmitting antenna 105 and the power-receiving antenna 205 are electromagnetically coupled. By passing an AC current through the power-transmitting antenna 105, the magnetic flux passing through the power-receiving antenna 205 is changed, inducing a voltage in the power-receiving antenna 105. When all (100%) of the magnetic flux generated by the power-transmitting antenna passes through the power-receiving antenna, the coupling coefficient (represented by k or k value), which indicates the coupling state between the power-transmitting and power-receiving antennas, becomes, for example, "k = 1." When 70% of the magnetic flux generated by the power-transmitting antenna passes through the power-receiving antenna, "k = 0.7." In this case, the remaining (30%) magnetic flux generated by the power-transmitting antenna is leakage flux. This is the magnetic flux generated by the power-transmitting antenna that has not yet passed through the power-receiving antenna. Therefore, when the coupling between the power transmitting antenna and the power receiving antenna is good and the k value is large, the power transmission efficiency from the TX 100 to the RX 200 is high. Conversely, when the coupling is poor and the k value is small, the power transmission efficiency from the TX 100 to the RX 200 is low.

[0168] Factors that contribute to a decrease in the coupling coefficient include the presence of foreign matter (such as a metal piece) between the power transmitting antenna and the power receiving antenna, and misalignment between the power transmitting antenna and the power receiving antenna. Alternatively, the distance between the power transmitting antenna and the power receiving antenna is long. When a foreign object is placed between the power transmitting antenna and the power receiving antenna, there is a possibility of heat generation in the foreign object. When there is misalignment or separation between the power transmitting antenna and the power receiving antenna, leakage magnetic flux increases, and there is a possibility of significant noise being generated in the surrounding area. When the k value is small, appropriate control is required to achieve safer and higher-quality wireless power transmission. In this embodiment, in order to improve the detection accuracy of foreign matter and the detection accuracy in the case of misalignment or large distance, a process for detecting the coupling state (including the coupling coefficient) between the power transmitting antenna and the power receiving antenna is performed.

[0169] Will refer to Figure 12A and Figure 12B Describes the measurement method for the coupling status index of the power transmitting antenna and the power receiving antenna. Figure 12A This is an equivalent circuit diagram for illustrating the first measurement method. The following shows the definitions of various quantities related to the power transmission antenna (power transmission coil) on the primary side (TX 100).

[0170] ●r1: Winding resistance of the power transmission antenna

[0171] L1: Self-inductance of the power transmission antenna

[0172] V1: Transmission voltage (input voltage) measured by the TX 100 and applied to the transmission antenna

[0173] The following shows the definitions of various quantities related to the power receiving antenna (power receiving coil) on the secondary side (RX 200).

[0174] ●r2: Winding resistance of the power receiving antenna

[0175] L2: Self-inductance of the receiving antenna

[0176] V2: The power receiving voltage (output voltage) measured by the RX 200 and applied to the power receiving antenna

[0177] The coupling coefficient k between the power transmitting antenna and the power receiving antenna can be calculated using the following formula 2.

[0178] (Formula 2)

[0179] The value of the coupling coefficient k may be referred to as a "k value."

[0180] When the TX 100 calculates the coupling coefficient k, the RX 200 notifies the TX 100 of the measured power receiving voltage V2 and the value of the self-inductance L2 of the power receiving antenna, which is previously stored by the RX 200. The TX 100 calculates the k value by using the measured power transmitting voltage V1, the previously stored value of the self-inductance L1 of the power transmitting antenna, and the power receiving voltage V2 and self-inductance L2 values ​​received from the RX 200. Alternatively, the RX 200 may notify the TX 100 of V2 and a constant calculated using all or either L1 or L2, and the TX 100 may calculate the k value by using V2, the constant received from the RX 200, and the power transmitting voltage V1 measured by the TX 100.

[0181] On the other hand, when the RX 200 calculates the coupling coefficient k, the TX 100 notifies the RX 200 of the measured power transmission voltage V1 and the previously stored value of the power transmission antenna's self-inductance L1. The RX 200 calculates the k value using the measured power reception voltage V2, the previously stored value of the power reception antenna's self-inductance L2, and the values ​​of the power transmission voltage V1 and self-inductance L1 received from the TX 100. Alternatively, the TX 100 may notify the RX 200 of V1 and a constant calculated using either or both of L1 and L2, and the RX 200 may calculate the k value using the constant received from the TX 100, V1, and the power reception voltage V2 measured by the RX 200.

[0182] Regarding the power transmission voltage V1, the TX 100 actually measures the voltage applied to the power transmission antenna, or calculates the voltage based on the set value of the power transmission power. Alternatively, the power transmission voltage V1 can be used as the set value of the power transmission voltage during power transmission. The power transmission voltage V1 applied to the power transmission antenna can be obtained from the power transmission voltage (represented by V3) applied to the circuit (e.g., inverter) of the power transmission unit 103 of the TX 100 and the voltage applied across the resonant capacitor 107. Here, the power transmission voltage V3 applied to the circuit of the power transmission unit 103 of the TX 100 is, for example, the inverter input voltage input to the inverter of the power transmission unit 103 of the TX 100 or the inverter output voltage output from the inverter. In this case, the TX 100 can also calculate the power transmission voltage V3 based on the set value of the power transmission power. Alternatively, the TX 100 can actually measure the power transmission voltage V3 and the voltage applied across the resonant capacitor 107 and calculate the power transmission voltage V1 using these values. Alternatively, the TX 100 may transmit the measured power transmission voltage V3 and the value of the voltage applied between both ends of the resonance capacitor 107 to the RX 200, and the RX 200 may calculate the k value by obtaining the power transmission voltage V1.

[0183] When the TX 100 or the RX 200 performs the first measurement, the RX 200 may turn off the third switch unit 213 to perform control so that the terminal of the power receiving antenna 205 enters an open circuit state. Figure 12AAs shown, both ends of the power receiving antenna can be set to an open circuit state. Since there is no influence from the resonant capacitor 211, the power receiving unit 203, the charging unit 206, or the battery 207 in the first measurement, the coupling coefficient k can be measured with higher accuracy. The power receiving voltage V2 applied to the power receiving antenna can be obtained from the power receiving voltage (represented by V4) applied to the circuit (e.g., the rectifier) ​​of the power receiving unit 203 of the RX 200 and the voltage applied across the resonant capacitor 211. Here, the power receiving voltage V4 applied to the circuit (e.g., the rectifier) ​​of the power receiving unit 203 of the RX 200 is, for example, the rectifier input voltage input to the rectifier of the power receiving unit 203 of the RX 200. Alternatively, the power receiving voltage V2 applied to the power receiving antenna can be obtained from the power receiving voltage (represented by V5) applied to the circuit (e.g., the rectifier) ​​of the power receiving unit 203 of the RX 200 and the voltage applied across the resonant capacitor 211. Here, the power receiving voltage V5 applied to the circuit of the power receiving unit 203 of the RX 200 is, for example, the rectifier output voltage output from the rectifier of the power receiving unit 203 of the RX 200. In this case, the RX 200 can actually measure the power receiving voltage V4 and the voltage applied across the resonant capacitor 211 and use these values ​​to obtain the power receiving voltage V2. Alternatively, the RX 200 can actually measure the power receiving voltage V5 and the voltage applied across the resonant capacitor 211 and use these values ​​to obtain the power receiving voltage V2. Alternatively, the RX 200 can transmit the measured power receiving voltage V4 and the voltage applied across the resonant capacitor 211 to the TX 100, and the TX 100 can calculate the k value by obtaining the power receiving voltage V2. Alternatively, the RX 200 can transmit the measured power receiving voltage V5 and the voltage applied across the resonant capacitor 211 to the TX 100, and the TX 100 can calculate the k value by obtaining the power receiving voltage V2.

[0184] Alternatively, when the TX 100 or RX 200 performs the first measurement, the RX 200 may be controlled to enter a light load state or a connected load state. By maintaining the load state of the RX 200 constant, the coupling coefficient k can be measured with higher accuracy. Alternatively, the TX 100 or RX 200 may be controlled to perform the first measurement in both a state where the RX 200 is in a light load state and a state where the RX 200 is in a connected load state. Alternatively, the TX 100 or RX 200 may be controlled to perform the first measurement in each of three or more load states. By measuring the coupling state in multiple load states of the RX 200 and determining the coupling state based on these measurement results, the coupling state can be determined with higher accuracy.

[0185] In addition to the coupling coefficient, there are several other indicators that indicate the electromagnetic coupling state between the power-transmitting and power-receiving antennas. In this embodiment, these indicators are collectively referred to as "coupling state indicators." Each coupling state indicator has a value corresponding to the electromagnetic coupling state between the power-transmitting and power-receiving antennas.

[0186] The content of this embodiment can also be similarly applied to the case where other coupling state indicators besides the coupling coefficient are used.

[0187] For example, one method for calculating the coupling state index is to use the power transmission voltage V3 applied to the circuit (such as the inverter) of the power transmission unit 103 of the TX 100 and the power reception voltage (represented by V4) applied to the circuit (such as the rectifier) ​​of the power reception unit 203 of the RX 200. Here, the power transmission voltage V3 applied to the circuit of the power transmission unit 103 of the TX 100 is, for example, the inverter input voltage input to the inverter of the power transmission unit 103 of the TX 100 or the inverter output voltage output from the inverter. Here, the power reception voltage V4 applied to the circuit of the power reception unit 203 of the RX 200 is, for example, the rectifier input voltage input to the rectifier of the power reception unit 203 of the RX 200. A process for calculating the coupling state index between the power transmitting antenna and the power receiving antenna can be executed. Alternatively, the coupling state index between the power transmitting and receiving antennas can be calculated using the power transmission voltage V3 applied to the circuit (e.g., inverter) of the power transmission unit 103 of the TX 100 and the power reception voltage (represented by V5) of the circuit (e.g., rectifier) ​​of the power reception unit 203 of the RX 200. Here, the power reception voltage V5 applied to the circuit of the power reception unit 203 of the RX 200 is, for example, the rectifier output voltage output from the rectifier of the power reception unit 203 of the RX 200. Alternatively, the power reception voltage V5 is the voltage applied to the load (charging unit, battery). The TX 100 can notify the RX 200 of the power transmission voltage V3, and the RX 200 can calculate the coupling state index using the notified V3 and either V4 or V5. At this time, the TX 100 may notify the RX 200 of a constant calculated by using the electrical characteristics (eg, L1) of the power transmitting antenna, and the RX 200 may calculate the coupling state index by using the constant.

[0188] Alternatively, the RX 200 notifies the TX 100 of the power receiving voltage V4 or the power receiving voltage V5, and the TX 100 calculates the value of the coupling state index using the notified V4 or V5 and V3. In this case, the RX 200 may notify the TX 100 of a constant calculated using the electrical characteristics of the power receiving antenna (e.g., L2), and the TX 100 may calculate the coupling state index using this constant.

[0189] TX 100 and RX 200 exchange information related to voltage values ​​V1 to V5, the values ​​of self-inductances L1 and L2, or the electrical characteristics of the power transmitting and receiving antennas. The timing for measuring voltage values ​​and exchanging information will be described below. For example, voltage values ​​are measured during the Ping phase. During the Ping phase, TX 100 transmits a digital Ping to RX 200. Therefore, any voltage value V1, V2, V3, V4, or V5 occurring during the transmission of the digital Ping can be used. During the Ping phase, TX 100 and RX 200 measure any value V1 to V5 and store and retain that value in memory 106 or memory 208. Alternatively, TX 100 transmits a predetermined packet to RX 200 to notify RX 200 of the timing for measuring voltage values. Upon receiving this predetermined packet, RX 200 measures any voltage value V2, V4, or V5. RX 200 measures any of the values ​​V2, V4, and V5 and stores and retains the value in memory 208. Alternatively, RX 200 transmits a predetermined packet to TX 100 to notify TX 100 of the timing for measuring the voltage value. When RX 200 receives the predetermined packet, RX 200 measures any of the voltage values ​​V1 and V3. TX 100 measures any of the values ​​V1 and V3 and stores and retains the value in memory 106.

[0190] TX 100 transmits a predetermined transmission request packet to RX 200, requesting the transmission of a packet containing information regarding any or all of voltage values ​​V2, V4, and V5. Upon receiving this transmission request packet, RX 200 transmits the predetermined packet containing information regarding any or all of voltage values ​​V2, V4, and V5 to TX 100. TX 100 receives the predetermined packet containing information regarding any or all of voltage values ​​V2, V4, and V5, notified from RX 200, and stores this information in memory 106. The information contained in the predetermined packet may include not only the voltage of RX 200 but also information regarding received power, the requested received power value, the value of self-inductance L2, or a constant calculated using the electrical characteristics of the power-receiving antenna. Alternatively, the information contained in the predetermined packet may include information regarding the temperature of RX 200. TX 100 can receive information from RX 200 and use this information and the calculated coupling status indicator to perform more appropriate control. A signal strength data packet can be used as the predetermined packet to notify TX 100 of information related to RX 200. Alternatively, the predetermined packet can be an identification data packet or an extended identification data packet during the configuration phase. Alternatively, the predetermined packet can be a configuration data packet. Alternatively, the predetermined packet can be a packet during the calibration phase or the power transfer phase. In other words, the predetermined packet can be RP1, RP2, or RP0. This configuration is not limited to the example of using the voltage value generated by TX 100 when transmitting a digital ping. Any of the voltage values ​​V1 to V5 generated by TX 100 when transmitting an analog ping during the selection phase can be used. Alternatively, any of the voltage values ​​V1 to V5 generated by TX 100 when transmitting power to RX 200 during the power transfer phase can be used.

[0191] RX 200 transmits a predetermined transmission request packet to TX 100, requesting transmission of a packet containing information related to any or all of voltage values ​​V1 and V3. Upon receiving the transmission request packet, TX 100 transmits the predetermined packet containing information related to any or all of voltage values ​​V1 and V3 to RX 200.

[0192] The RX 200 receives a predetermined packet containing information regarding any or all of the voltage values ​​V1 and V3 notified from the TX 100 and stores this information in the memory 208. The information contained in the predetermined packet may include not only the voltage of the TX 100 but also information regarding the transmitted power value, the transmittable power value, the self-inductance L1 value, or a constant calculated using the electrical characteristics of the power transmitting antenna. Alternatively, the predetermined packet may include the foreign object detection results from the aforementioned foreign object detection methods (power loss method, quality factor measurement method, waveform attenuation method) and information regarding the temperature of the TX 100. The RX 200 can receive this information from the TX 100 and use this information and the calculated coupling state index to perform more appropriate control. A power transmitter capabilities (CAP) data packet may be used as the predetermined packet to notify the RX 200 of information related to the TX 100. Alternatively, a power transmitter identification (ID) data packet may be used to notify the RX 200 of information related to the TX 100. This configuration is not limited to the example of using the voltage value generated by the TX 100 when transmitting a digital ping. Any of the voltage values ​​V1 to V5 generated by the TX 100 when transmitting an analog ping during the selection phase may be used. Alternatively, any of the voltage values ​​V1 to V5 generated by the TX 100 when transmitting power to the RX 200 during the power transfer phase may be used.

[0193] When the RX 200 performs the first measurement, it can disconnect third switch unit 213 between resonant capacitor 211 and power receiving unit 203 to control the terminals of the circuit formed by power receiving antenna 205 and resonant capacitor 211 to open circuit. Therefore, when performing the first measurement method, there is no influence from power receiving unit 203, charging unit 206, or battery 207, and the coupling state index can be measured with higher accuracy.

[0194] Next, a second measurement method will be described as another example of a method for measuring the coupling state index of the power transmitting antenna and the power receiving antenna. The measurement performed in the second measurement method is referred to as a second measurement. Figure 12B is an equivalent circuit diagram for illustrating the second measurement method. r1, r2, L1 and L2 are Figure 12A The definitions of various quantities related to the power transmitting antenna (coil) on the primary side (TX 100) are shown below.

[0195] V6: Input voltage of the power transmitting antenna (power transmitting voltage) when the power receiving antenna is short-circuited

[0196] V7: Input voltage of the power transmitting antenna (power transmitting voltage) when the power receiving antenna is in an open circuit state

[0197] I1: Current flowing through the power transmitting antenna when the power receiving antenna is short-circuited

[0198] I2: Current flowing through the power transmitting antenna when the power receiving antenna is open

[0199] The coupling coefficient k can be calculated by using the following formula 3.

[0200] (Formula 3)

[0201] In Equation 3, Lsc represents the inductance of the power-transmitting antenna when both ends of the power-receiving antenna are short-circuited. For example, control unit 201 sets third switch unit 213 and second switch unit 210 to the ON state (short-circuited state). The value of Lsc can be obtained by measuring the inductance of the power-transmitting antenna in this state. The inductance of the power-transmitting antenna can be obtained from the input voltage V6 and current I1 of the power-transmitting antenna.

[0202] In Equation 3, Lopen represents the inductance of the power-transmitting antenna when both ends of the power-receiving antenna are open-circuited. For example, the control unit 201 sets the third switch unit 213 to the OFF state (open-circuited state). The value of Lopen can be obtained by measuring the inductance of the power-transmitting antenna in this state. The inductance of the power-transmitting antenna can be obtained from the input voltage V7 and current I2 of the power-transmitting antenna. In the second measurement method, the coupling state indicator (coupling coefficient) can be obtained from the input voltage and current of the power-transmitting antenna in each of the cases where both ends of the power-receiving antenna are short-circuited and when both ends of the power-receiving antenna are open-circuited.

[0203] The TX 100 can calculate a coupling state index based on the power transmission voltage and current applied to the circuit (e.g., inverter) included in the power transmission unit 103. In this case, the input voltages V6 and V7 represent the power transmission voltages applied to the circuit (e.g., inverter) included in the power transmission unit 103. Here, the power transmission voltages V6 and V7 applied to the circuit included in the power transmission unit 103 of the TX 100 are, for example, the inverter input voltage or the inverter output voltage. The input voltages V6 and V7 may also be the voltage applied between the two terminals of a series resonant circuit consisting of a power transmission antenna and a resonant capacitor. Alternatively, the power transmission voltage applied to the circuit (e.g., inverter) included in the power transmission unit 103 and the voltage applied across the resonant capacitor 107 may be measured, and the voltage applied to the power transmission antenna may be calculated based on the results. In other words, the coupling state index can be obtained based on the measurement results of the power transmission voltage applied to the circuit (e.g., inverter) included in the power transmission unit 103 and the voltage applied across the resonant capacitor 107. The power transmission voltage applied to the circuit (eg, inverter) included in the power transmission unit 103 in this case can be calculated by the TX 100 according to the setting value of the transmitted power.

[0204] exist Figure 12B In the example, current I1 or I2 is not limited to the current flowing through the power transmitting antenna and may be the current flowing through the circuit included in the power transmitting unit 103 (e.g., an inverter). Here, the current flowing through the circuit included in the power transmitting unit 103 of the TX 100 is, for example, the inverter input current or the inverter output current. The example describes an example in which the control unit 201 controls the second switching unit 210 and the third switching unit 213 to achieve the open-circuit state and the short-circuit state of the power receiving antenna. These states can be achieved by the power receiving unit 203. A light load state can be used instead of the short-circuit state. A connected load state can be used instead of the open-circuit state.

[0205] In the second measurement method, the TX 100 can calculate the coupling state index by measuring the input voltages V6 and V7 and the currents I1 and I2. Therefore, information such as the voltage values ​​measured by the RX 200 and the inductance of the power-receiving antenna is not required, and thus, there is no need for the RX 200 to notify the TX 100 of this information. However, when the TX 100 measures the input voltage V6 and current I1, the RX 200 must short-circuit the two terminals of the circuit including the power-receiving antenna. When the TX 100 measures the input voltage V7 and current I2, the RX 200 must open-circuit the two terminals of the circuit including the power-receiving antenna. In other words, the RX 200 must control the two terminals of the circuit including the power-receiving antenna to either short-circuit or open-circuit, depending on the timing at which the TX 100 measures the input voltage and current. When this control is complete, the TX 100 performs the measurement. Regarding the measurement timing, the TX 100 either determines the timing and notifies the RX 200 of it, or the RX 200 determines the timing and notifies the TX 100 of it. When the RX 200 completes control to set the two terminals of the circuit including the power receiving antenna to a short-circuit state or an open-circuit state, the RX 200 notifies the TX 100. These notifications are made by communication based on the WPC standard between the first communication unit 104 of the TX 100 and the first communication unit 204 of the RX 200, or by communication based on a standard other than the WPC standard between the second communication unit 109 of the TX 100 and the second communication unit 212 of the RX 200.

[0206] For example, during the Ping phase, input voltages V6 and V7 and currents I1 and I2 are measured. During the Ping phase, TX 100 transmits a digital Ping to RX 200. Therefore, the values ​​of V6, V7 and currents I1 and I2 occurring when the digital Ping is transmitted can be used. During the Ping phase, TX 100 acquires the values ​​of V6, V7, I1, and I2, stores these values ​​in memory 106, and calculates the coupling state indicator. This configuration is not limited to the example of using voltage and current values ​​occurring when TX 100 transmits a digital Ping. For example, the values ​​of V6, V7, I1, and I2 generated by TX 100 when transmitting an analog Ping during the Select phase can be used. Alternatively, the voltage values ​​V6, V7, I1, and I2 occurring when TX 100 transmits power to RX 200 during the Power Transfer phase can be used.

[0207] The present disclosure relates to a method for measuring a coupling state index for a power transmitting antenna and a power receiving antenna, and is applicable to both a first measurement method and a second measurement method. Hereinafter, a method for setting a state judgment threshold for a coupling state index obtained by the first measurement method or the second measurement method will be described. State judgment refers to a judgment related to the detection of a foreign object between the power transmitting antenna and the power receiving antenna, a judgment related to the detection of misalignment between the power transmitting antenna and the power receiving antenna, or a judgment related to the detection of separation between the power transmitting antenna and the power receiving antenna, etc. The presence or absence of a state abnormality can be determined using the state judgment threshold by performing the first measurement method or the second measurement method. Hereinafter, the first to fourth threshold setting methods will be described.

[0208] The first threshold setting method uses the value of the coupling state indicator in the absence of a state abnormality as the threshold value for the coupling state indicator used for state detection between the power-transmitting and power-receiving antennas. During state detection, judgment results such as "state abnormality present," "high probability of state abnormality," "low probability of state abnormality," and "no state abnormality" are obtained. Assume that the RX 200 is placed on the test TX 100 and there is no state abnormality between the power-transmitting and power-receiving antennas. In this case, the value of the coupling state indicator between the test TX 100 (including the power-transmitting antenna) and the RX 200 (including the power-receiving antenna) can be set as the threshold value. The value of the coupling state indicator (threshold value) measured in advance is stored in the memory of the RX 200, and the RX 200 notifies the TX 100 of the threshold value. The TX 100 uses the threshold value to perform judgment processing related to state detection. Regarding the threshold value, the RX 200 can transmit a threshold value included in a FOD status data packet predefined in the WPC standard to the TX 100. Alternatively, the value of the coupling state indicator between the power-transmitting and power-receiving antennas that achieves a predetermined power transfer efficiency can be set as the threshold value. In the state detection, for example, the following judgment results can be obtained.

[0209] "Unable to achieve the expected power transmission efficiency" or "Weak coupling between the power transmitting and receiving antennas"

[0210] There is a high possibility that the expected power transmission efficiency cannot be achieved or there is a possibility that the coupling between the power transmitting antenna and the power receiving antenna is weak.

[0211] ● "There is a high probability that the predetermined power transmission efficiency will be achieved" or "There is a probability that the coupling between the power transmitting antenna and the power receiving antenna is good"

[0212] "The expected power transmission efficiency is achieved" or "The coupling between the power transmitting antenna and the power receiving antenna is good"

[0213] Here, it is assumed that the RX 200 is placed on the test TX 100, there are no abnormalities between the power transmitting and power receiving antennas, and the predetermined power transfer efficiency is achieved. In this case, the value of the coupling state indicator between the test TX 100 (including the power transmitting antenna) and the RX 200 (including the power receiving antenna) can be set as a threshold. The RX 200 stores the pre-measured value of the coupling state indicator in memory as the threshold and notifies the TX 100 of the threshold. The TX 100 uses the threshold to perform determination processing related to state detection. Regarding the threshold, the RX 200 can transmit the threshold included in the FOD status data packet predefined in the WPC standard to the TX 100.

[0214] The second threshold setting method involves the TX 100 and RX 200 setting a threshold value based on the coupling state indicator measured using the first or second measurement method under a predetermined state. The predetermined state is "a state in which no abnormality exists between the power-transmitting and power-receiving antennas." Methods for confirming this state can include foreign object detection using a power loss method, a waveform attenuation method, a quality factor measurement method, or foreign object detection based on the temperature of the TX 100 or RX 200. As a result, if it is determined that no abnormality exists, it can be confirmed with a high probability that "no abnormality exists between the power-transmitting and power-receiving antennas."

[0215] In other words, this confirmation is performed using a method and device other than the first or second measurement method. Consequently, when it is determined that there is no abnormality (or no foreign matter), the coupling status indicator is measured using the first or second measurement method, and an appropriate threshold is set based on the measurement result.

[0216] For example, in the WPC standard, during the negotiation phase or the renegotiation phase, a foreign object detection process using the quality factor measurement method is performed. As a result of the foreign object detection process, if it is determined that there is "no state abnormality" (or "no foreign object"), the coupling state index is measured using the first measurement method or the second measurement method after the negotiation phase or the renegotiation phase. A more appropriate threshold value can be set based on the measurement result. During the power transmission phase, a foreign object detection process using the power loss method is performed. After the foreign object detection process is performed, the coupling state index is measured using the first measurement method or the second measurement method, and a more appropriate threshold value is set based on the measurement result. Alternatively, the foreign object detection process can be performed during the selection phase or the ping phase using a quality factor, etc. In this case, after the foreign object detection process is performed, the coupling state index is measured using the first measurement method or the second measurement method, and an appropriate threshold value can be set based on the measurement result. Alternatively, during the power transmission phase, the foreign object detection process using the waveform attenuation method described above is performed. After the foreign object detection process is performed, the coupling state index is measured using the first measurement method or the second measurement method, and a more appropriate threshold value is set based on the measurement result.

[0217] Next, we will refer to Figure 13 The third threshold setting method is described. Figure 13 : is a diagram for illustrating a threshold setting method in state detection using a coupling state index. Figure 13 In the graph, the horizontal axis represents transmitted power, and the vertical axis represents the coupling state index. On the graph line represented by straight line segment 1202, point 1200 corresponds to the transmitted power value Pt1 and the coupling state index value k1, and point 1201 corresponds to the transmitted power value Pt2 and the coupling state index value k2. Point 1203 on the graph line corresponds to the transmitted power value Pt3 and the coupling state index value k3. The first or second measurement method described above can be used to calculate each coupling state index value.

[0218] like Figure 3 As shown, the charging unit 206 and battery 207 are connected to the power receiving unit 203 of the RX 200 as loads, so the calculated coupling state index value changes depending on the state of the load. In order to determine the presence of a state abnormality based on the state of the load, a threshold for the coupling state index is required. First, when power is transmitted from the TX 100, the RX 200 controls the load so that the load enters a light load state. The light load state is a state in which no power is supplied to the load of the RX 200, or only power less than or equal to a threshold is supplied to the load of the RX 200. Alternatively, the light load state is a load state in which the power value received by the RX 200 falls within a predetermined range (hereinafter referred to as the "fifth range").

[0219] Assume that the transmitted power value of TX 100 in this state is Pt1. RX 200 then transmits a packet requesting measurement of a coupling state index to TX 100. Alternatively, TX 100 transmits a packet requesting measurement of a coupling state index to RX 200. In this state, TX 100 and RX 200 measure the transmitted voltage on the TX 100 side and the received voltage on the RX 200 side. TX 100 and RX 200 exchange information (such as values ​​V1 to V7, the values ​​of self-inductances L1 and L2, and constants calculated using the electrical characteristics of the transmitting and receiving antennas), and either TX 100 or RX 200 calculates a coupling state index value k1. When RX 200 calculates the coupling state index value k1, RX 200 notifies TX 100 of the result. When TX 100 calculates the coupling state index value k1, TX 100 notifies RX 200 of the result and Pt1. At this time, the TX 100 recognizes the transmitted power value Pt1 and stores the CP 1200 for associating Pt1 with k1 in the memory. Alternatively, the RX 200 stores the CP 1200 for associating Pt1 with k1 in the memory.

[0220] Subsequently, when power is transmitted from TX 100, RX 200 controls the load of RX 200 so that the load enters a connected load state. The connected load state is a state in which maximum power is supplied to the load of RX 200, or power greater than or equal to a threshold is supplied to the load of RX 200. Here, "maximum power" refers to power having a value close to a reference power. Alternatively, the light load state is a load state in which the power received by RX 200 falls within a predetermined range (hereinafter referred to as the "sixth range"). Here, the sixth range is a range of power values ​​higher than the fifth range. Assume that the power transmitted by TX 100 in this state is Pt2. RX 200 then transmits a packet requesting measurement of a coupling state indicator to TX 100. Alternatively, TX 100 transmits a packet requesting measurement of a coupling state indicator to RX 200. In this state, TX 100 and RX 200 measure the transmitted voltage on the TX 100 side and the received voltage on the RX 200 side. TX 100 and RX 200 exchange information such as values ​​V1 to V7, the values ​​of self-inductances L1 and L2, and constants calculated using the electrical characteristics of the power transmitting and receiving antennas. TX 100 or RX 200 then calculates a coupling state index value k2. When RX 200 calculates coupling state index value k2, RX 200 notifies TX 100 of the result. When TX 100 calculates coupling state index value k2, TX 100 notifies RX 200 of the result and Pt2. TX 100 stores CP 1201, used to associate Pt2 with k2, in memory. Alternatively, RX 200 stores CP 1201, used to associate Pt2 with k2, in memory. TX 100 then performs linear interpolation between CP 1200 and CP 1201 to generate line segment 1202. Line segment 1202 represents the relationship between the transmitted power and the coupling state index when there are no abnormalities around the TX 100 and RX 200. Using line segment 1202, the TX 100 can estimate the coupling state index value for each transmitted power value when there are no abnormalities around the TX 100 and RX 200. For example, assume that 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, the TX 100 can calculate a threshold value for determining the presence or absence of an abnormality for each transmitted power value. For example, the coupling state index value obtained by adding a predetermined value (a value corresponding to the measurement error) to the estimated coupling state index value when there are no abnormalities at the transmitted power value can be set as the determination threshold.

[0221] Thus, the CAL process performed by the TX 100 and RX 200, in which the TX 100 acquires a combination of a transmitted power value and a coupling state index value, is referred to as "CAL process for the coupling state index measurement method." Performing the calibration process again to update or add calibration points after the calibration process has already been performed is referred to as recalibration processing, abbreviated as ReCAL processing. After notifying the TX 100 of the execution of the control, the RX 200 can perform control to set the load to a light load state, or perform control to set the load to a connected load state. Either of these two control processes can be performed first.

[0222] In this embodiment, for example, during the calibration phase, an operation for calculating a judgment threshold value for detecting the state of each load (or each transmitted power value) is performed. During the calibration phase, the TX 100 acquires data required for detecting a foreign object using the power loss method. At this time, the TX 100 acquires data related to each power loss amount when the load state of the RX 200 is a light load state, and data related to each power loss amount when the load state of the RX 200 is a connected load state. Therefore, during the calibration phase, when the RX 200 enters the light load state or when the RX 200 enters the connected load state, Figure 13 The measurement of CP 1200 and CP 1201 in the RX 200 can be performed simultaneously with the measurement of power loss. In other words, when the TX 100 receives the first reference received power information from the RX 200, in addition to the predetermined processing to be performed during the calibration phase, the TX 100 also measures CP 1200. The first reference received power information is information related to RP1 predefined in the WPC standard. Alternatively, other messages can be used. When the TX 100 receives the second reference received power information from the RX 200, in addition to the predetermined processing to be performed during the calibration phase, the TX 100 also measures CP 1201. The second reference received power information is information related to RP2 predefined in the WPC standard. Alternatively, other messages can be used. This eliminates the need to set separate time periods for measuring CP 1200 and CP 1201, allowing CP 1200 and CP 1201 to be measured within a shorter time period.

[0223] The fourth threshold setting method involves the TX 100 or RX 200 presetting a threshold for a coupling state indicator with a value within a predetermined range. The threshold is a common value independent of the RX 200 to which power is transmitted and is a predetermined value maintained by the TX 100 or RX 200. The threshold can be a fixed value independent of the situation, or a variable value determined by the TX 100 or RX 200 depending on the situation. For example, when the coupling state indicator is used as the coupling coefficient k, the value of k ranges from 0 ≤ k ≤ 1. For example, when 0 ≤ k < 0.2, the TX 100 or RX 200 determines that a state abnormality exists, and when 0.2 ≤ k < 0.5, the TX 100 or RX 200 determines that a state abnormality is highly likely. When 0.5 ≤ k < 0.8, the TX 100 or RX 200 determines that a state abnormality is less likely, and when 0.8 ≤ k ≤ 1, the TX 100 or RX 200 determines that a state abnormality does not exist. Data of conditions related to the k value is held in advance in a memory, and the determination process is performed based on the data.

[0224] Alternatively, when "0 ≤ k < 0.2," the TX 100 or RX 200 determines, for example, that "the predetermined power transmission efficiency is not achieved" or "the coupling between the power transmitting and receiving antennas is weak." When "0.2 ≤ k < 0.5," the TX 100 or RX 200 determines that "there is a high probability that the predetermined power transmission efficiency cannot be achieved" or "the coupling between the power transmitting and receiving antennas is weak." When "0.5 ≤ k < 0.8," the TX 100 or RX 200 determines that "the predetermined power transmission efficiency is highly likely to be achieved" or "there is a high probability that the coupling between the power transmitting and receiving antennas is good." When "0.8 ≤ k ≤ 1," the TX 100 or RX 200 determines that "the predetermined power transmission efficiency is achieved" or "the coupling between the power transmitting and receiving antennas is good." Data on conditions related to the k value is stored in memory in advance, and the determination process is performed based on this data.

[0225] In setting a judgment threshold associated with state detection using a coupling state indicator, a value obtained by adding a predetermined value (a value corresponding to a measurement error) to a coupling state indicator value calculated based on a measurement result or received information may also be set as the judgment threshold. As described above, the number of thresholds is not limited to one, and multiple thresholds may be set in a stepwise manner.

[0226] Next, we will describe the timing for calculating the coupling state between the power-transmitting and power-receiving antennas using the first or second measurement method. The coupling state is calculated (measured) when the RX 200 transmits a predetermined packet to the TX 100. Here, the predetermined packet is a signal strength data packet transmitted by the RX 200 to the TX 100. Alternatively, during the configuration phase, the predetermined packet may be an identification data packet or an extended identification data packet. Alternatively, the predetermined packet may be a configuration data packet. Alternatively, the predetermined packet may be a packet during the calibration phase or the power transfer phase. In other words, the predetermined packet may be RP1, RP2, or RP0.

[0227] When TX 100 receives a predetermined packet from RX 200, it calculates a coupling state index between the power-transmitting and power-receiving antennas. TX 100 then makes a determination by comparing the calculated coupling state index with the determination threshold set using the aforementioned method. If TX 100 determines that there is no abnormality, it transmits a positive acknowledgment (ACK) to RX 200 or status information indicating that there is no abnormality. If TX 100 determines that there is a low probability of an abnormality or a high probability of an abnormality, it transmits status information indicating the respective determination results to RX 200. If TX 100 determines that there is an abnormality, it transmits a negative acknowledgment (NAK) or status information indicating that there is an abnormality to RX 200.

[0228] Alternatively, when the TX 100 determines that "the predetermined power transmission efficiency is achieved" or "the coupling state between the power transmitting antenna and the power receiving antenna is good," the TX 100 transmits an acknowledgement (ACK) or status information indicating the determination result to the RX 200. When the TX 100 determines that "the predetermined power transmission efficiency is likely to be achieved" or "the coupling state between the power transmitting antenna and the power receiving antenna is likely to be good," the TX 100 transmits status information indicating the determination result to the RX 200. When the TX 100 determines that "the predetermined power transmission efficiency is likely to be unattainable" or "the coupling state between the power transmitting antenna and the power receiving antenna is likely to be weak," the TX 100 transmits status information indicating the determination result to the RX 200. When the TX 100 determines that "the predetermined power transmission efficiency is unattainable" or "the coupling state between the power transmitting antenna and the power receiving antenna is weak," the TX 100 transmits a negative acknowledgement (NAK) or status information indicating the determination result to the RX 200.

[0229] Status information refers to the following numerical values ​​depending on the status.

[0230] Status information "0" corresponds to the judgment result of "no status abnormality" or "predetermined power transmission efficiency is achieved" or "the coupling state between the power transmitting antenna and the power receiving antenna is good"

[0231] Status information "1" corresponds to the judgment result "low possibility of abnormal state" or "high possibility of obtaining predetermined power transmission efficiency" or "probability of good coupling between the power transmitting antenna and the power receiving antenna"

[0232] Status information "2" corresponds to the judgment result "high probability of abnormality" or "high probability of failure to achieve predetermined power transmission efficiency" or "possibility of weak coupling between the power transmitting antenna and the power receiving antenna"

[0233] Status information "3" corresponds to the judgment result "abnormality exists" or "unable to obtain the expected power transmission efficiency" or "weak coupling between the power transmitting antenna and the power receiving antenna"

[0234] Alternatively, the coupling state is calculated (measured) when the TX 100 transmits a predetermined packet to the RX 200. Here, the predetermined packet refers to a power transmitter capability (CAP) data packet transmitted by the TX 100 to the RX 200. Alternatively, the predetermined packet is a power transmitter identification (ID) data packet.

[0235] When RX 200 receives a predetermined packet from TX 100, it calculates the coupling state index between the power-transmitting and power-receiving antennas. RX 200 then makes a determination by comparing the calculated coupling state index with the determination threshold set using the aforementioned method. If RX 200 determines that there is no abnormality, it transmits a predetermined packet containing the determination result to TX 100. If RX 200 determines that there is a low probability of an abnormality or a high probability of an abnormality, it transmits a predetermined packet containing status information indicating the respective determination results to TX 100. If RX 200 determines that there is an abnormality, it transmits a predetermined packet containing status information indicating the determination result to TX 100.

[0236] Alternatively, when the RX 200 determines that "the predetermined power transmission efficiency is achieved" or "the coupling state between the power transmitting antenna and the power receiving antenna is good," the RX 200 transmits status information indicating the determination result to the TX 100. When the RX 200 determines that "the predetermined power transmission efficiency is likely to be achieved" or "the coupling state between the power transmitting antenna and the power receiving antenna is likely to be good," the RX 200 transmits status information indicating the determination result to the TX 100. When the RX 200 determines that "the predetermined power transmission efficiency is likely to be unattainable" or "the coupling state between the power transmitting antenna and the power receiving antenna is likely to be weak," the RX 200 transmits status information indicating the determination result to the TX 100. When the RX 200 determines that "the predetermined power transmission efficiency is unattainable" or "the coupling state between the power transmitting antenna and the power receiving antenna is weak," the RX 200 transmits status information indicating the determination result to the TX 100.

[0237] Status information refers to the following numerical values ​​depending on the status.

[0238] Status information "0" corresponds to the judgment result of "no status abnormality" or "predetermined power transmission efficiency is achieved" or "the coupling state between the power transmitting antenna and the power receiving antenna is good"

[0239] Status information "1" corresponds to the judgment result "low possibility of abnormal state" or "high possibility of obtaining predetermined power transmission efficiency" or "probability of good coupling between the power transmitting antenna and the power receiving antenna"

[0240] Status information "2" corresponds to the judgment result "high probability of abnormality" or "high probability of failure to achieve predetermined power transmission efficiency" or "possibility of weak coupling between the power transmitting antenna and the power receiving antenna"

[0241] Status information "3" corresponds to the judgment result "abnormality exists" or "unable to obtain the expected power transmission efficiency" or "weak coupling between the power transmitting antenna and the power receiving antenna"

[0242] Next, we will describe the operation of the TX 100 to properly and quickly charge the battery of the RX 200. For fast charging, higher power needs to be transferred from the TX 100 to the RX 200. The WPC standard includes a baseline power profile (BPP) that transfers less than 5 watts of power to the RX 200 and an extended power profile (EPP) that transfers less than 15 watts of power to the RX 200. In this embodiment, a scenario in which higher power than the EPP is transferred is assumed. In other words, a scenario in which the TX 100 transfers more than 15 watts of power to the RX 200 is assumed. The state (scheme, mode) of wireless power transfer exceeding 15 watts to the RX 200 is referred to as a fast charging mode or a fast charging scheme. Alternatively, the state (scheme, mode) in which the TX 100 and RX 200 can set the GP higher than 15 watts is referred to as a fast charging mode or a fast charging scheme. It is assumed that the maximum GP that can be set in the fast charging mode or the fast charging scheme is 50 watts.

[0243] In the following, we will use Figure 14 Flowchart of the power transmission equipment in Figure 15 The flowchart of the power receiving device in FIG15 illustrates the operation of the TX 100 and RX 200 when wireless charging is performed in fast charging mode. Below, the negotiation phase and subsequent phases (not shown) after the TX 100 and RX 200 have performed the aforementioned selection phase, ping phase, and configuration phase will be described. First, during the negotiation phase, the RX 200 requests the transmission of information indicating whether the power transmitting device supports fast charging mode (F1501). Specifically, this request is made using the General Request (GRQ) packet predefined in the WPC standard.

[0244] When TX 100 receives a request from RX 200 to transmit information indicating whether the power transmitting device supports the fast charging mode (F1401), TX 100 transmits a packet containing information indicating that TX 100 supports the fast charging mode to RX 200 (F1402). Here, "supporting the fast charging mode" means that TX 100 or RX 200 has hardware, control devices, and functions that enable TX 100 to operate in the fast charging mode for RX 200. This packet is a power transmitter capability (CAP) data packet. Alternatively, the packet is a power transmitter identification (ID) data packet. These packets include a 1-bit field for indicating whether the fast charging mode is supported. When TX 100 notifies RX 200 that TX 100 supports the fast charging mode, TX 100 stores a "1" in the relevant field; however, when TX 100 notifies RX 200 that TX 100 does not support the fast charging mode, TX 100 stores a "0" in the relevant field. The meanings of "1" and "0" stored in the relevant fields can be reversed.

[0245] Alternatively, the power transmitter identification (ID) packet includes a field for storing version information of the WPC standard. The fields storing the major and minor versions of the power transmitter ID packet store information that can identify the version of the WPC standard (Qi standard) supported by the TX 100. These fields are used to store information related to the version that supports MPP (described later) and information related to the version that supports both MPP and the rapid charging mode. When the TX 100 does not support MPP (described later), the TX 100 is controlled not to notify the RX 200 of the above information indicating that the TX 100 supports the rapid charging mode. In other words, in the above example, when the TX 100 "does not support MPP," the TX 100 is controlled not to transmit "version information supporting both MPP and the rapid charging mode" to the RX 200. For example, the TX 100 may transmit "version information not supporting MPP or the rapid charging mode." When the TX 100 notifies the RX 200 of the above information indicating that the TX 100 supports the fast charge mode, the TX 100 needs to support the MPP (described later). In other words, in the above example, when the TX 100 "supports the fast charge mode," the TX 100 is controlled to transmit "version information supporting both the MPP and the fast charge mode" to the RX 200.

[0246] The RX 200 determines whether it has received a packet from the TX 100 containing information indicating that the TX 100 supports the fast charge mode (F1502). If the RX 200 has not received a packet, the RX 200 periodically or irregularly repeats the determination in F1502 until a predetermined time has elapsed ("No" in F1502 and "No" in F1517). If the RX 200 has not received a packet containing information indicating that the TX 100 supports the fast charge mode within the predetermined time ("No" in F1502 and "Yes" in F1517), the RX 200 terminates this process. In other words, the RX 200 returns to the selection phase.

[0247] When RX 200 has received a packet from TX 100 containing information indicating that TX 100 supports the fast charge mode ("Yes" in F1502), RX 200 transmits a packet to TX 100 containing information indicating whether RX 200 supports the fast charge mode (F1503). This packet is, for example, a FOD status data packet. These packets include a 1-bit field indicating whether the fast charge mode is supported. When RX 200 notifies TX 100 that RX 200 supports the fast charge mode, RX 200 stores a "1" in the relevant field; however, when RX 200 notifies TX 100 that RX 200 does not support the fast charge mode, RX 200 stores a "0" in the relevant field. Here, RX 200 is a powered device that supports the fast charge mode, so RX 200 transmits a packet containing information indicating that RX 200 supports the fast charge mode. The meanings of the "1" and "0" stored in the relevant fields can be reversed. When this packet is used during the negotiation phase, other packets may be used in place of the FOD status data packet. TX 100 determines whether TX 100 has received a packet from RX 200 containing information indicating that RX 200 supports the fast charge mode (F1403). If TX 100 has not received a packet, TX 100 periodically or irregularly performs the determination in F1403 until a predetermined time has elapsed ("No" in F1403, "No" in F1418). If TX 100 has not received a packet containing information indicating that RX 200 supports the fast charge mode within the predetermined time ("No" in F1403, "Yes" in F1418), TX 100 terminates this process. In other words, TX 100 returns to the selection phase.

[0248] The above describes an example in which the RX 200 receives information indicating that the TX 100 supports the fast charge mode from the TX 100, and then transmits information indicating that the RX 200 supports the fast charge mode to the TX 100. However, the order of information transmission and reception can be reversed. In other words, the TX 100 can receive information indicating that the RX 200 supports the fast charge mode from the RX 200, and then the TX 100 can transmit information indicating that the RX 200 supports the fast charge mode to the RX 200. For example, the information indicating that the RX 200 supports the fast charge mode can be transmitted before the configuration phase. This information can be stored in a signal strength packet transmitted from the RX 200 to the TX 100 during the ping phase. Alternatively, this information can be stored in a packet transmitted during the configuration phase. This packet can be an identification packet, an extended identification packet, or a configuration packet.

[0249] The identification packet includes fields for storing version information for the WPC standard. The fields storing the major and minor versions of the identification (ID) packet store information identifying the version of the WPC standard (Qi standard) supported by the RX 200. These fields are used to store information regarding the version supporting MPP (described later) and information regarding the version supporting both MPP and the fast charging mode. When the RX 200 does not support MPP (described later), the RX 200 is controlled not to notify the TX 100 of the above information indicating that the TX 100 supports the fast charging mode. In other words, in the above example, when the RX 200 "does not support MPP," the RX 200 is controlled not to transmit "version information supporting both MPP and the fast charging mode" to the TX 100. For example, the RX 200 may transmit "version information not supporting either MPP or the fast charging mode." When the RX 200 notifies the TX 100 of the above information indicating that the RX 200 supports the fast charging mode, the RX 200 is required to support MPP (described later). In other words, in the above example, when the RX 200 “supports the quick charge mode,” the RX 200 is controlled to transmit “version information supporting both the MPP and quick charge modes” to the TX 100 .

[0250] Only either one of the TX 100 and the RX 200 may transmit, to the other of the RX 200 and the TX 100 , a packet containing information indicating that “the either one of the TX 100 and the RX 200 supports the fast charge mode”.

[0251] Subsequently, RX 200 transmits a packet (F1504) containing "information for determining whether the conditions for transitioning to the fast charging mode are satisfied" to TX 100. A FOD status data packet may be used as the packet. The FOD status data packets transmitted in F1503 and F1504 may be the same single packet, or may be FOD status data packets different from each other. In the former case, F1503 and F1504 are performed in one step. When the packet is used during the negotiation phase, other packets may be used instead of the FOD status data packet. The packet containing "information for determining whether the conditions for transitioning to the fast charging mode are satisfied" and the packet containing information indicating that "TX 100 supports the fast charging mode" may be packets of the same type, or may be packets of different types.

[0252] Here, a “condition for transitioning to the rapid charge mode” will be described. This condition may be all of the conditions listed below, a combination of some of the conditions, or any one of the conditions.

[0253] [First condition]

[0254] The first condition is that the TX 100 and RX 200 support MPP. MPP stands for Magnetic Power Profile, and the WPC has announced that it will adopt MPP as the next-generation standard "Qi2," the successor to the wireless power receiving standard "Qi." MPP has the function of accurately fixing the TX 100 and RX 200 in a predetermined position. Several devices can be conceived to accurately fix the TX 100 and RX 200 in a predetermined position. For example, by using magnets built into the TX 100 and RX 200 respectively, the power transmitting antenna (transmitting coil) of the TX 100 and the power receiving antenna (receiving coil) of the RX 200 can be made to face each other in the correct position. In other words, in this case, MPP is an extended function of BPP and can be regarded as a solution for aligning the power transmitting device and the power receiving device using magnets. The magnet can be a permanent magnet or an electromagnet. Increasing the power transmission efficiency to reduce power loss when transmitting high power in fast charging mode is also environmentally desirable. Therefore, when the TX 100 and RX 200 support MPP and can operate according to MPP, the TX 100 and RX 200 are controlled to operate in the fast charging mode. Therefore, in F1504, the RX 200 transmits a packet containing information indicating that the RX 200 can support MPP to the TX 100. When the RX 200 cannot operate according to MPP, the RX 200 transmits a packet containing information indicating that the RX 200 does not support MPP. In other words, in F1504, the RX 200 transmits a packet containing information indicating whether the power transmitting and receiving devices can be aligned using magnets.

[0255] [Second Condition]

[0256] The second condition is that the TX 100 and RX 200 have a predetermined method (device) as a method (device) for accurately fixing the TX 100 and RX 200 in a predetermined position. Alternatively, the second condition is that the TX 100 and RX 200 have a predetermined method (device) as a method (device) for accurately fixing the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 in a predetermined position. Several methods can be listed as methods for accurately fixing the TX 100 and RX 200 in a predetermined position, or methods for accurately fixing the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 in a preset position (alignment method).

[0257] <First Alignment Method>

[0258] This is a method in which magnets are built into the TX 100 and the RX 200, respectively, and the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 are made to face each other by using magnetic force.

[0259] <Second Alignment Method>

[0260] This is a method in which the TX 100 has a movable power transmitting antenna, and the power transmitting antenna of the TX 100 is moved near the power receiving coil of the RX 200 so that the power transmitting antenna and the power receiving antenna of the RX 200 face each other.

[0261] <Third Alignment Method>

[0262] This is a method in which the TX 100 has a holder for fixing the RX 200 so that the RX 200 can be placed at a predetermined position on the TX 100, and the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 face each other by placing the RX 200 along the holder.

[0263] In these alignment methods, the positional accuracy with which the TX 100's power-transmitting antenna and the RX 200's power-receiving antenna face each other varies depending on the method used. As described above, the higher the positional accuracy with which the TX 100's power-transmitting antenna and the RX 200's power-receiving antenna face each other, the higher the power transmission efficiency, which is desirable. Therefore, when the TX 100 and RX 200 support a predetermined alignment method that allows the TX 100's power-transmitting antenna and the RX 200's power-receiving antenna to be aligned with a high degree of accuracy exceeding a predetermined level, the TX 100 and RX 200 are controlled to operate in the fast charging mode.

[0264] For example, among the alignment methods described above, the first alignment method is listed as an alignment method that can align the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 with a high degree of accuracy higher than a predetermined level. By using magnets built into the TX 100 and RX 200, respectively, the power transmitting antenna (power transmitting coil) of the TX 100 and the power receiving antenna (power receiving coil) of the RX 200 can be made to face each other (in the correct position). Therefore, when the TX 100 and RX 200 support the first alignment method, the TX 100 and RX 200 are controlled to operate in the fast charging mode. In F1504, the RX 200 transmits a packet containing information indicating that "the RX 200 supports the first alignment method" to the TX 100. For example, the following can be listed as a method of notifying information related to the alignment method.

[0265] (1) Method of providing notification of alignment methods supported by the RX 200 through predetermined information

[0266] For example, when the RX 200 supports the first alignment method, the RX 200 incorporates information “1” into a predetermined packet and transmits the predetermined packet to the TX 100. When the RX 200 supports the second alignment method, the RX 200 incorporates information “2” into a predetermined packet and transmits the information “2” in the predetermined packet to the TX 100. When the RX 200 supports the third alignment method, the RX 200 incorporates information “3” into a predetermined packet and transmits the predetermined packet to the TX 100.

[0267] (2) Method of providing notification of whether the RX 200 supports the first alignment method through predetermined information

[0268] For example, when the RX 200 supports the first alignment method, the RX 200 incorporates information “1” into a predetermined packet and transmits the predetermined packet to the TX 100. When the RX 200 does not support the first alignment method, the RX 200 incorporates information “2” into a predetermined packet and transmits the predetermined packet to the TX 100.

[0269] [Third Condition]

[0270] The third condition is that the coupling state index between the power transmitting antenna of TX 100 and the power receiving antenna of RX 200 is greater than or equal to a predetermined value or exceeds a predetermined value. The method for measuring the coupling state index between the power transmitting antenna of TX 100 and the power receiving antenna of RX 200 or the method for setting a threshold value to determine whether the coupling state index is good or not is as described above.

[0271] When the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 face each other, the coupling state index value also reaches a favorable value (a large value in the case of the coupling coefficient), thereby achieving high power transmission efficiency, which is desirable. Therefore, when the measured coupling state index between the TX 100 and RX 200 is greater than or equal to a set threshold, or exceeds the set threshold, the TX 100 and RX 200 are controlled to operate in the fast charging mode.

[0272] In F1504, RX transmits a packet containing "information used by TX to calculate the coupling state index between the power transmitting antenna and the power receiving antenna" to TX. The information received from RX, which TX needs to calculate the coupling state index between the power transmitting antenna and the power receiving antenna, is as described in the description of the coupling state index measurement method above.

[0273] The above description is based on a method for measuring a coupling state indicator between the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200, or a method for setting a threshold value for the coupling state indicator, as a method for determining the coupling state indicator between the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200. Other methods for determining the coupling state indicator between the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 will be described below.

[0274] <Other Methods for Determining the Coupling Status Index Between the TX 100's Power Transmitting Antenna and the RX 200's Power Receiving Antenna>

[0275] The RX 200 measures the received power value and notifies the TX 100 of the measurement result. For example, during the Ping phase, the TX 100 transmits a DP, and the RX 200 measures the voltage of the received DP. The RX 200 stores the measured voltage value as a signal strength value in a signal strength data packet. The RX 200 transmits this packet to the TX 100, and the TX 100 receives the packet from the RX 200. The signal strength value is a value measured by the RX 200 as a voltage value in relation to the power transmitted by the TX 100. In other words, the magnitude of the received power voltage value (measured value) indicates the strength of the coupling between the power transmitting antenna and the power receiving antenna. The TX 100 compares the signal strength value in the packet with a threshold. When the signal strength value of the TX 100 is greater than or equal to the threshold, the TX 100 is determined to be in a strong coupling state; however, when the signal strength value is less than the threshold, the TX 100 is determined to be in a weak coupling state. The signal strength value is obtained by measuring the power transmitted by the TX 100 as a voltage value by the RX 200. The RX 200 determines the strength of the coupling between the power-transmitting and power-receiving antennas based on a comparison between the measured signal strength value and a threshold value. When the signal strength value is greater than or equal to the threshold value, the RX 200 determines that the coupling state is strong; however, when the signal strength value is less than the threshold value, the RX 200 determines that the coupling state is weak. When the coupling state between the power-transmitting and power-receiving antennas is strong, the TX 100 or RX 200 is controlled to operate in the fast charging mode. When the coupling state between the power-transmitting and power-receiving antennas is weak, the TX 100 or RX 200 is controlled not to operate in the fast charging mode.

[0276] The threshold setting described in the "Alternative Method for Determining the Coupling Status Indicator Between the Power-Transmitting Antenna of the TX 100 and the Power-Receiving Antenna of the RX 200" can be performed as follows. Specifically, in the threshold setting method for measuring the coupling status indicator, the first or fourth threshold setting method can be used, and the TX 100 can maintain the threshold value in advance. The RX 200 can notify the TX 100 of the threshold value. Alternatively, the TX 100 and RX 200 can maintain the same threshold value in advance.

[0277] [Fourth condition]

[0278] The fourth condition is when no foreign matter is detected using the above-mentioned foreign matter detection method, or when the foreign matter presence probability determined by the above-mentioned foreign matter detection method is less than or equal to a predetermined value, or less than a predetermined value. The foreign matter detection methods include the power loss method, the quality factor measurement method, and the waveform attenuation method. The detailed operations for executing each foreign matter detection method and the method for setting the threshold for determining the presence or absence of foreign matter or the probability of foreign matter presence are described above.

[0279] Performing wireless power transmission with foreign matter near the power transmitting antenna of the TX 100 and the power receiving antenna of the RX 200 is undesirable because heat generation and other factors can occur in the foreign matter. In particular, as the amount of power transferred from the TX 100 to the RX 200 increases, the amount of heat generated also increases, which is undesirable. Therefore, when there is no foreign matter, or the probability of the presence of a foreign matter is less than or equal to a predetermined value, or less than a predetermined value, the TX 100 and RX 200 are controlled to operate in the fast charging mode.

[0280] In F1504, the RX 200 transmits a packet containing "information for the TX 100 to perform the foreign object detection method" to the TX 100. The information received from the RX 200 required for the TX 100 to perform the foreign object detection method is as described above. This information also includes information for determining the threshold value to be set for performing the foreign object detection method.

[0281] A specific rapid charge mode transition judgment threshold used to determine whether the conditions for transitioning to rapid charge mode are met can be set to a threshold used to perform a foreign object detection method and determine the presence or probability of a foreign object. In other words, the threshold of the foreign object detection method used when operating according to an EPP for power transmission of 15 watts or less and the rapid charge mode transition judgment threshold are set to be different from each other. For example, the rapid charge mode transition judgment threshold is set to a stricter value than the threshold of the foreign object detection method used when operating according to an EPP for power transmission of 15 watts or less. The threshold is set by adding a predetermined margin to a reference value; however, the rapid charge mode transition judgment threshold is set to have a smaller margin than the threshold of the foreign object detection method used when operating according to an EPP for power transmission of 15 watts or less. Therefore, a safer transition to high power transmission in rapid charge mode can be achieved.

[0282] [Fifth Condition]

[0283] The fifth condition is that the temperature at a predetermined point in the TX 100 or RX 200 is lower than or equal to a predetermined value, or lower than a predetermined value. When high power transmission is performed in rapid charge mode, components of the TX 100 or RX 200 (such as the power transmitting antenna, the power receiving antenna, and the battery) generate more heat than when low power transmission is performed. Therefore, when the TX 100 or RX 200 is at a high temperature and the mode is shifted to rapid charge mode and high power transmission is performed, this may cause damage to the TX 100 or RX 200. Therefore, when the temperature of the TX 100 or RX 200 is lower than or equal to a predetermined value, or lower than a predetermined value, the TX 100 and RX 200 are controlled to operate in rapid charge mode.

[0284] Here, we will describe a control method based on the temperature of the TX 100. It is assumed that each of the TX 100 and RX 200 has temperature sensors in multiple locations. In particular, the temperature sensors are placed at a higher density on the power transmitting antenna 105, the charging base 300, and the power receiving antenna 205 than elsewhere.

[0285] In F1504, the RX 200 transmits a packet including “timing information for determining the timing at which the TX 100 acquires temperature information from the temperature sensor of the TX 100” to the TX 100. This information may include information for determining a threshold value of a temperature to be set.

[0286] [Sixth Condition]

[0287] The sixth condition is when TX and RX are operating within the aforementioned MPP. TX and RX execute predetermined control and operate in accordance with the MPP. Then, when TX and RX are operating in accordance with the MPP, it is determined that "the conditions for transitioning to the rapid charge mode are met."

[0288] The first to sixth conditions have been described as "conditions for transitioning to the rapid charge mode." Regarding the "conditions for transitioning to the rapid charge mode," a combination of some of the first to sixth conditions described above may be defined as the "condition for transitioning to the rapid charge mode." For example, a situation where both the first and second conditions described above are satisfied may be set as the "condition for transitioning to the rapid charge mode." A combination of not only two of the first to sixth conditions but also three, four, five, or all of the first to sixth conditions may be set as the "condition for transitioning to the rapid charge mode."

[0289] Subsequently, the TX 100 determines whether it has received a packet from the RX 200 containing "information for determining whether the conditions for transitioning to the rapid charge mode are satisfied" (F1404). If the TX 100 has not received a packet, the TX 100 periodically or irregularly performs the determination in F1404 until a predetermined time has elapsed ("No" in F1404, "No" in F1419). If the TX 100 has not received a packet containing "information for determining whether the conditions for transitioning to the rapid charge mode are satisfied" after the predetermined time has elapsed ("No" in F1404, "Yes" in F1419), the TX 100 terminates this process. In other words, the TX 100 transitions to the selection phase.

[0290] When the TX 100 receives a packet containing "information for determining whether the conditions for transitioning to the rapid charge mode are satisfied" ("Yes" in F1404), the TX 100 determines whether the conditions for transitioning to the rapid charge mode are satisfied based on the information (F1405). If it is determined that the conditions for transitioning to the rapid charge mode are satisfied ("Yes" in F1405), the process proceeds to F1406. If it is determined that the conditions for transitioning to the rapid charge mode are not satisfied ("No" in F1405), the process proceeds to F1415.

[0291] Here, the determination processing related to the above-mentioned conditions will be described.

[0292] [When the First Condition is Included as a Condition for Transitioning to the Rapid Charging Mode]

[0293] When the TX 100 has received a packet containing information indicating that the RX 200 supports MPP and the TX 100 also supports MPP, the TX 100 determines that the conditions for transitioning to the rapid charge mode are met, and the process proceeds to F1406. Here, when the TX 100 has received a packet not containing information indicating that the RX 200 supports MPP, the TX 100 determines that the conditions for transitioning to the rapid charge mode are not met, and the process proceeds to F1415. Alternatively, when the TX 100 has received a packet containing information indicating that the RX 200 does not support MPP, the TX 100 determines that the conditions for transitioning to the rapid charge mode are not met, and the process proceeds to F1415. In other words, when both the TX 100 and the RX 200 support MPP, the TX 100 is controlled to operate in the rapid charge mode. On the other hand, when at least either one of the TX 100 and the RX 200 does not support the MPP, the TX 100 is controlled not to operate in the fast charge mode.

[0294] [When the Second Condition is Included as the Condition for Transition to the Rapid Charging Mode]

[0295] When the TX 100 has received a packet containing information indicating that the RX 200 supports the first alignment method, and the TX 100 also supports the first alignment method, the TX 100 determines that the conditions for transitioning to the rapid charge mode are met. In other words, the process proceeds to F1406. On the other hand, when the TX 100 has received a packet not containing information indicating that the RX 200 supports the first alignment method, the TX 100 determines that the conditions for transitioning to the rapid charge mode are not met, and the process proceeds to F1415. Alternatively, when the TX 100 has received a packet containing information indicating that the RX 200 does not support the first alignment method, the TX 100 determines that the conditions for transitioning to the rapid charge mode are not met, and the process proceeds to F1415. In other words, when both the TX 100 and the RX 200 support the first alignment method, the TX 100 is controlled to operate in the rapid charge mode. On the other hand, when at least one of the TX 100 and the RX 200 does not support the first alignment method, the TX 100 is controlled not to operate in the fast charge mode.

[0296] [When the Third Condition is Included as a Condition for Transition to the Rapid Charging Mode]

[0297] The TX 100 calculates the coupling state index between the power transmitting antenna and the power receiving antenna using the information used by the TX 100 to calculate the coupling state index. If the coupling state index satisfies a predetermined condition, the TX 100 determines that the conditions for transitioning to the rapid charge mode are met, and processing proceeds to F1406. Here, "satisfying the predetermined condition" means that the coupling state index is greater than or equal to a predetermined threshold, or exceeds the threshold. On the other hand, if the coupling state index does not satisfy the predetermined condition, the TX 100 determines that the conditions for transitioning to the rapid charge mode are not met, and processing proceeds to F1415.

[0298] [When the Fourth Condition is Included as a Condition for Transition to the Rapid Charging Mode]

[0299] The TX 100 performs foreign object detection using the "information for the foreign object detection method performed by the TX 100" received from the RX 200. If the result obtained by using the foreign object detection method satisfies a predetermined condition, the TX 100 determines that the conditions for transitioning to the rapid charge mode are met, and processing proceeds to F1406. Here, "satisfying the predetermined condition" means that the result of foreign object detection using the foreign object detection method indicates the absence of foreign object, or that the probability of the presence of foreign object is less than or equal to a predetermined value, or less than a predetermined value. If the result of foreign object detection using the foreign object detection method does not satisfy the predetermined condition, the TX 100 determines that the conditions for transitioning to the rapid charge mode are not met, and processing proceeds to F1415.

[0300] [When the Fifth Condition is Included as a Condition for Transition to the Rapid Charging Mode]

[0301] When TX 100 receives a packet from RX 200 containing "timing information for determining the timing at which TX 100 acquires temperature information from TX 100's temperature sensor," TX 100 acquires the value of the temperature sensor from TX 100 at the time TX 100 receives the packet. TX 100 then determines whether the conditions for transitioning to rapid charge mode are met. When the acquired temperature sensor value meets the predetermined conditions, TX 100 determines that the conditions for transitioning to rapid charge mode are met, and processing proceeds to F1406. Here, "meeting the predetermined conditions" means that the temperature sensor value is less than or equal to a predetermined value, or is less than a predetermined value. "Not meeting the predetermined conditions" means that the temperature sensor value is greater than or equal to a predetermined value, or exceeds a predetermined value.

[0302] In the above example, it is assumed that the TX 100 acquires the value of the temperature sensor of the TX 100 at the time when the TX 100 receives "timing information for determining the timing at which the TX 100 acquires temperature information from the temperature sensor of the TX 100" from the RX 200. However, the configuration is not limited to this. For example, the TX 100 may acquire temperature information from the temperature sensor of the TX 100 at a timing determined by the TX 100 at predetermined intervals.

[0303] The TX 100 is not limited to determining whether to transition to rapid charge mode based on the acquired temperature sensor value. For example, the TX 100 may calculate the temperature increase rate based on multiple temperature detection values ​​acquired at predetermined timings. In this case, when the temperature increase rate is lower than or equal to a predetermined threshold, or is lower than a predetermined threshold, the TX 100 may determine that "the conditions for transitioning to rapid charge mode are met." If the temperature increase rate is higher than or equal to the predetermined threshold, or exceeds the predetermined threshold, the TX 100 may determine that "the conditions for transitioning to rapid charge mode are not met."

[0304] The RX 200 may obtain the value of its temperature sensor and transmit a packet containing "temperature information from the RX 200 temperature sensor" to the TX 100. This information may include information for determining a temperature threshold to be set. In this case, if the received value of the RX 200 temperature sensor satisfies a predetermined condition, the TX 100 determines that the condition for transitioning to the rapid charge mode is met, and processing proceeds to F1406. Here, "meeting the predetermined condition" means that the value of the RX 200 temperature sensor is less than or equal to a predetermined value, or is less than a predetermined value. If the value of the RX 200 temperature sensor does not satisfy the predetermined condition, the TX 100 determines that the condition for transitioning to the rapid charge mode is not met, and processing proceeds to F1415. Here, "not meeting the predetermined condition" means that the value of the RX 200 temperature sensor is greater than or equal to a predetermined value, or exceeds a predetermined value.

[0305] The TX 100 can calculate the temperature increase rate based on the values ​​of multiple temperature sensors acquired from the RX 200, and when the temperature increase rate is lower than or equal to a predetermined threshold, or is lower than a predetermined threshold, it can be determined that "the conditions for transitioning to the rapid charge mode are satisfied." Then, when the temperature increase rate is higher than or equal to the predetermined threshold, or exceeds the predetermined threshold, the TX 100 can determine that "the conditions for transitioning to the rapid charge mode are not satisfied."

[0306] Using the above method, the TX 100 determines in F1405 whether the conditions for transitioning to the rapid charge mode are met. The flow from F1405 onwards will be described below. If the TX 100 determines in F1405 that the conditions for transitioning to the rapid charge mode are met, processing proceeds to F1406. The TX 100 then transmits a packet containing information indicating that the conditions for transitioning to the rapid charge mode are met to the RX 200 (F1406). This packet is used as an ACK, which is a positive response. The RX 200 determines whether the RX 200 has received a packet containing information indicating that the conditions for transitioning to the rapid charge mode are satisfied from the TX 100 (F1505). When the RX 200 has not received the packet from the TX 100 (for example, when the RX 200 has received a NAK as a negative acknowledgment), the RX 200 regularly or irregularly performs the determination in F1505 until a predetermined period of time has elapsed ("No" in F1505, "No" in F1518). When the RX 200 has not received a packet containing information indicating that the conditions for transitioning to the rapid charge mode are satisfied within the predetermined time ("No" in F1505, "Yes" in F1518), the RX 200 ends the process. In other words, the RX 200 returns to the selection stage.

[0307] When the judgment in F1505 is positive, RX 200 transmits a packet containing information indicating that RX 200 requests to transition to fast charging mode to TX 100 (F1506). TX 100 determines whether TX 100 has received a packet containing information indicating "request to transition to fast charging mode" from RX 200 (F1407). A FOD status data packet is used as this packet. This packet includes a 1-bit field indicating whether transition to fast charging mode is requested. When RX 200 requests TX 100 to transition to fast charging mode, RX 200 stores "1" (or "0") in the relevant field; however, when RX 200 does not request TX 100 to transition to fast charging mode, RX 200 stores "0" (or "1") in the relevant field. When this packet is used during the negotiation phase, other packets may be used instead of the FOD status data packet.

[0308] If the TX 100 has not received a packet containing information requesting a transition to the rapid charge mode (No in F1407), the process proceeds to F1415. If the TX 100 has received the packet (Yes in F1407), the TX 100 transmits an ACK as a positive response to the RX 200 (F1408). The TX 100 then proceeds to F1409. The RX 200 determines whether it has received an ACK from the TX 100 (F1507). If the RX 200 has not received an ACK from the TX 100, the RX 200 periodically or irregularly repeats the determination in F1507 until a predetermined time has elapsed (No in F1507, No in F1519). If the RX 200 has not received an ACK after the predetermined time has elapsed (No in F1507, Yes in F1519), the RX 200 terminates the process. In other words, the RX 200 returns to the selection phase. When the RX 200 has received ACK from the TX 100 ("YES" in F1507), the process proceeds to F1508.

[0309] Next, the operation of TX 100 in fast charging mode from F1409 will be described. In F1409, TX 100 performs negotiation or renegotiation corresponding to the power of fast charging mode. Specifically, TX 100 can set the negotiable load power to more than 15 watts. More specifically, TX 100 can set the negotiable load power to potential load power. Potential load power is the highest level of GP that TX 100 can negotiate. Therefore, GP can be set to more than 15 watts. However, due to other conditions, there is a possibility that the negotiable load power is not set to potential load power. As a result, even in fast charging mode, GP is not always set to more than 15 watts. Negotiation or renegotiation is an operation performed during the above-mentioned negotiation stage. Through the above-mentioned control, TX 100 and RX 200 agree on GP through negotiation.

[0310] Then, the process proceeds to F1410, and a CAL process or a ReCAL process corresponding to the power of the fast charge mode is performed. The CAL process or the ReCAL process is an operation performed during the above-mentioned calibration phase. When the GP is set to more than 15 watts, Figure 4 The Pt2 in the CMOS also exceeds 15 watts. Figure 4 The straight line 1002 in FIG. 1 is created to cover the transmitted power and received power in the fast charging mode. Figure 4 Straight line 1002 in FIG. is created taking into account the GP in rapid charge mode. The calibration points created during the CAL process or ReCAL process in rapid charge mode can be controlled to be greater than those created during the CAL process or ReCAL process when operating according to the BPP or EPP. Alternatively, the calibration points created during the CAL process or ReCAL process in rapid charge mode can be controlled to create a predetermined number or more. The term "predetermined number" refers to, for example, "3" or a number greater than or equal to "3." Alternatively, the number of calibration points created during the CAL process or ReCAL process in rapid charge mode can be determined based on the GP value. For example, when the GP is 20 watts, the number of calibration points is "3," when it is 30 watts, the number of calibration points is "4," and when it is 40 watts, the number of calibration points is "5." The above-described method for determining the number of calibration points can be applied to the "calibration process for the power loss method," the "CAL process for the waveform attenuation method," and the "CAL process for the coupling state index measurement method."

[0311] The calibration point can be controlled to create a calibration point corresponding to the following power.

[0312] ●Ensure load power

[0313] ●Request load power

[0314] ●Negotiable load power

[0315] Potential load power

[0316] Maximum power value or reference power

[0317] The above-described calibration point creation method can be applied to the “calibration process of the power loss method,” the “calibration process of the waveform attenuation method,” and the “calibration process of the coupling state index measurement method.”

[0318] Subsequently, the process proceeds to F1411, and TX 100 begins transmitting less than 5 watts or less of power to RX 200. The process then proceeds to F1412, and authentication defined in the WPC standard is performed. Here, authentication refers to the process of RX 200 authenticating TX 100. Authentication includes the process of RX 200 determining whether TX 100 supports authentication. If RX 200 determines that TX 100 supports authentication, RX 200 transmits a predetermined first packet to TX 100. RX 200 determines whether the response from TX 100, which has received the predetermined packet, meets predetermined conditions. If RX 200 determines that the predetermined conditions are met, RX 200 transmits a predetermined second packet to TX 100. RX 200 determines whether authentication is successful based on the content of the response from TX 100, which has received the predetermined packet (F1412). Alternatively, during authentication, in addition to the process of RX 200 authenticating TX 100, TX 100 may also perform a process of authenticating RX 200. Authentication includes a process in which TX 100 determines whether RX 200 supports authentication. If TX 100 determines that RX 200 supports authentication, TX 100 transmits a predetermined third packet to RX 200. TX 100 determines whether the response from RX 200, which has received the predetermined packet, satisfies a predetermined condition. If TX 100 determines that the predetermined condition is satisfied, TX 100 transmits a predetermined fourth packet to RX 200. TX 100 determines whether authentication is successful based on the content of the response from RX 200, which has received the predetermined packet (F1412). In this case, if RX 200 successfully authenticates TX 100 and TX 100 successfully authenticates RX 200, both TX 100 and RX 200 determine that "authentication is successful."

[0319] If authentication is successful ("YES" in F1412), the process proceeds to F1413, and the control during operation in the rapid charge mode, which will be described in the second embodiment, is executed. If authentication is successful, the RX 200 can receive power from the reliable TX 100. Therefore, when the RX 200 attempts to receive high power from the TX 100 in rapid charge mode, the RX 200 is controlled to transition to rapid charge mode only when authentication is successful. Rapid charge mode enables power transmission up to the GP determined in F1409. On the other hand, if authentication fails ("NO" in F1412), the process proceeds to F1415.

[0320] The operation performed in F1413 will be described in detail later in the second embodiment, and is a control for resolving problems during operation in the rapid charging mode. Subsequently, the process proceeds to F1414, and power transmission in the rapid charging mode is started. The operations from F1409 to F1414 have been described above.

[0321] Next, the TX 100's operations from F1415 onwards will be described. Operations from F1415 onwards are those when it is determined that the device is not in fast charge mode but is operating according to the BPP or EPP. In F1415, the TX 100 performs negotiation or renegotiation corresponding to the power of the BPP or EPP. Negotiation or renegotiation is an operation performed during the negotiation phase described above. The TX 100 and RX 200 set the GP to 5 watts or less in the BPP or 15 watts or less in the EPP. Specifically, the TX 100 sets the negotiable load power to 5 watts or less or 15 watts or less. Consequently, the GP is set to 5 watts or less or 15 watts or less.

[0322] Then, the process proceeds to F1416, and a CAL process or a ReCAL process corresponding to the power of BPP or EPP is performed. The CAL process or the ReCAL process is an operation performed in the above-mentioned calibration phase. Since the GP is set to 5 watts or less based on the BPP or the GP is set to 15 watts or less based on the EPP, Figure 4 The Pt2 in the device is also below 15 watts. Figure 4 The straight line 1002 in FIG. 1 is created to cover the transmitted power and received power of the BPP or EPP.

[0323] Figure 4 The straight line 1002 in FIG. 14 is created in consideration of the GP of the BPP or EPP. Subsequently, the process proceeds to F1417, and the TX 100 starts power transmission according to the BPP or EPP to the RX 200. The operations from F1415 to F1417 are described above.

[0324] Next, we will describe the RX 200's operation in Rapid Charge Mode, starting with F1508. In F1508, the RX 200 negotiates or renegotiates the power requirements for Rapid Charge Mode. Specifically, the RX 200 can set the requested load power to exceed 15 watts. Consequently, the GP can be set to exceed 15 watts. However, even in Rapid Charge Mode, the GP is not always set to exceed 15 watts. Negotiation or renegotiation is performed during the negotiation phase described above. Through the aforementioned control, the TX 100 and RX 200 negotiate and agree on a GP.

[0325] Then, the process proceeds to F1509, and a CAL process or a ReCAL process corresponding to the power of the rapid charge mode is executed. Since this process is described in the above F1410, the description of this process is omitted.

[0326] Subsequently, the process proceeds to F1510, and the RX 200 starts receiving power at less than 5 watts or less from the TX 100. Then, the process proceeds to F1511, and authentication as defined in the WPC standard is performed. When the authentication is successful ("Yes" in F1511), the process proceeds to F1512, and the control during operation in the fast charging mode described in the second embodiment is performed. Then, the process proceeds to F1513, and power reception in the fast charging mode is started. When the authentication fails ("No" in F1511), the process proceeds to F1514. The operations from F1508 to F1513 are described above.

[0327] Next, we will describe the RX 200's operations from F1514 onward. Operations from F1514 onward are those when it is determined that the system is not operating in fast charge mode but is operating according to the BPP or EPP. In F1514, the RX 200 negotiates or renegotiates the power level of the BPP or EPP. Negotiation or renegotiation is an operation performed during the negotiation phase described above. The RX 100 and RX 200 set the GP to 5 watts or less in the BPP or 15 watts or less in the EPP. Specifically, the RX 200 sets the requested load power to 5 watts or less or 15 watts or less. Consequently, the GP is set to 5 watts or less or 15 watts or less.

[0328] The process then proceeds to F1515, where a CAL process or ReCAL process corresponding to the power of the BPP or EPP is executed. This process is described in F1416 above, so its description is omitted. The process then proceeds to F1516, where the RX 200 begins receiving power from the TX 100 in accordance with the BPP or EPP. The operations from F1514 to F1516 have been described above.

[0329] Figure 16This is a sequence diagram for power transfer from TX 100 to RX 200 in rapid charge mode. Initially, RX 200 requests information indicating whether TX 100 supports rapid charge mode (S1601), and TX 100 receives the request (S1602). TX 100 and RX 200 each provide notification that the host device supports rapid charge mode (S1603, S1604). RX 200 provides a notification regarding information determining whether the "conditions for transitioning to rapid charge mode" are met (S1605). Based on this information, TX 100 determines whether the conditions for transitioning to rapid charge mode are met (S1606). Then, to satisfy the conditions for transitioning to rapid charge mode, TX 100 provides a notification that the conditions for transitioning to rapid charge mode are met (S1607). Subsequently, RX 200 provides a notification requesting transition to rapid charge mode (S1608). TX 100 then transmits an acknowledgment (ACK) (S1609). After that, the TX 100 and the RX 200 perform negotiation or renegotiation corresponding to the power of the rapid charge mode (S1610). Subsequently, the TX 100 and the RX 200 perform CAL processing or ReCAL processing corresponding to the power of the rapid charge mode (S1611). Then, the RX 200 performs authentication of the TX 100 (S1612). The TX 100 performs authentication of the RX 200 (S1612). When the authentication is successful (S1613), the TX 100 and the RX 200 perform "Control during Operation in Rapid Charge Mode" (S1614). Then, the TX 100 and the RX 200 start power transmission in the rapid charge mode (S1615).

[0330] The order of steps S1601 to S1607 until the RX 200 notifies the TX 100 of a request to transition to the rapid charge mode may be changed. For example, control may be performed so that steps S1601 to S1604 are performed after steps S1605 to S1607. In this case, if the TX 100 determines in S1606 that the conditions for transitioning to the rapid charge mode are not met, the TX 100 may be controlled not to perform S1607, and both the TX 100 and the RX 200 may be controlled not to perform steps S1601 to S1604.

[0331] <Various Modifications>

[0332] Figure 14 F1404 to F1406 and Figure 15 The functions of the controls described in F1504 to F1505 can be interchanged as follows.

[0333] For example, the TX 100 may notify the RX 200 via a predetermined packet containing information for determining whether the "conditions for transitioning to the fast charging mode" are satisfied. A power transmitter capability (CAP) packet may be used as this packet. Alternatively, a power transmitter identification (ID) packet may be used as this packet. However, these packets may be provided as a response to a general request (GRQ) packet from the RX 200. Specifically, initially, the RX 200 may use a GRQ packet to request transmission of information for determining whether the "conditions for transitioning to the fast charging mode" are satisfied. Then, in response to this request, the TX 100 may transmit information for determining whether the "conditions for transitioning to the fast charging mode" are satisfied.

[0334] The RX 200 may determine that the "condition for transitioning to the rapid charge mode" is satisfied, and notify the TX 100 of the determination result via a predetermined packet. This packet may be an ACK as a positive response.

[0335] The RX 200 may request a transition to the "fast charge mode" by using a predetermined packet. A FOD status data packet may be used as the packet.

[0336] The information transmitted from TX 100 to RX 200 for determining whether the "condition for transitioning to rapid charging mode" is satisfied is, for example, information indicating that "TX 100 supports MPP." Alternatively, as described in the description of the coupling state index measurement method, this information is information related to TX 100 required for RX 200 to calculate the coupling state index. This information may be a packet containing information indicating the timing for RX 200 to obtain the value of its temperature sensor. Alternatively, this information may be a packet containing information related to the value of TX 100's temperature sensor.

[0337] Alternatively, the following configuration can be adopted as another modification. In other words, initially, RX 200 notifies TX 100 of information for executing "foreign object detection processing" or "calculation of coupling state index." Then, TX 100 executes "foreign object detection processing" or "calculation of coupling state index" based on the information received from RX 200. Thereafter, TX 100 notifies RX 200 of the result of "foreign object detection processing" or "calculation of coupling state index." In other words, TX 100 notifies RX 200 of the value of the coupling state index, the presence or absence of foreign matter, or the probability of the presence of foreign matter. Then, RX 200 compares the result of "foreign object detection processing" or "calculation of coupling state index" received from TX 100 with a threshold value maintained by RX 200 to determine whether the "condition for transitioning to fast charging mode" is met. RX 200 requests transition to "fast charging mode" based on the determination result. In this case as well, when a combination of a plurality of conditions among the first to sixth conditions is satisfied, the RX200 may be controlled to determine that “the condition for transitioning to the rapid charge mode is satisfied”.

[0338] The RX 200 can perform the "Notification Requesting the Power Transmitting Device to Transition to Rapid Charge Mode" operation in F1506 during the power transmission phase. During the power transmission phase according to BPP or EPP, if the RX 200 intends to receive higher power or determines that predetermined conditions for receiving higher power are met, the RX 200 performs the operation in F1506. In this case, the TX 100 transmits an ACK as an operation in F1408, and the RX 200 receives an ACK as an operation in F1507. The TX 100 then transitions to the operation in F1409 and performs renegotiation corresponding to the power level in rapid charge mode. The TX 100 then transitions to the operation in F1410 and performs ReCAL corresponding to the power level in rapid charge mode. The TX 100 then performs the operations in F1412, F1413, and F1414. The RX 200 also transitions to the operation in F1508 and performs renegotiation corresponding to the power level in rapid charge mode. Then, the RX 200 transitions to the operation of F1509 and performs ReCAL corresponding to the power of the rapid charge mode. Then, the TX 100 performs the operations from F1510 to F1513.

[0339] In the above embodiment, an example of notifying the information indicating whether the fast charge mode is supported is described during the negotiation phase; however, the notification may be performed during other phases. For example, during the Ping phase, the RX 200 may use a signal strength packet to provide notification of information indicating whether the fast charge mode is supported. Alternatively, during the configuration phase, the RX 200 may use an identification packet to provide notification of information indicating whether the fast charge mode is supported. Alternatively, an extended identification packet or a configuration packet may be used. In this case, during Figure 15 F1503 should be conducted before F1501.

[0340] Packets during the calibration phase or the power transfer phase can be used. For example, RP1, RP2, or RP0 can be used. Therefore, the processing from F1503 onwards is performed during the renegotiation phase after the calibration phase and the power transfer phase.

[0341] In the above embodiment, an example of notifying the information for determining whether the "condition for transitioning to the fast charging mode" is satisfied during the negotiation phase is described; however, this notification may be performed during other phases. For example, the RX200 may use a signal strength packet during the Ping phase. Alternatively, an identification packet during the configuration phase may be used. Alternatively, an extended identification packet or a configuration packet may be used. In this case, Figure 15 F1504 should be performed before F1501.

[0342] Packets during the calibration phase or the power transfer phase can be used. For example, RP1, RP2, or RP0 can be used. Therefore, the processing from F1503 onwards is performed during the renegotiation phase after the calibration phase and the power transfer phase.

[0343] In the above embodiment, an example is described in which the TX 100 performs F1409 and F1410 before F1412. Alternatively, the TX 100 may perform F1409 and F1410 after F1412, and then perform F1413 and F1414. An example is described in which the RX 200 performs F1508 and F1509 before F1511. Alternatively, the RX 200 may perform F1508 and F1509 after F1511, and then perform F1512 and F1513. In other words, when authentication is successful, the TX 100 and RX 200 perform negotiation or renegotiation corresponding to the rapid charge mode, as well as CAL or ReCAL. The TX 100 and RX 200 then execute control for operation in rapid charge mode and begin power transmission and reception in rapid charge mode.

[0344] In the first embodiment described above, Figure 14 From F1415 onwards in FIG14 , the TX 100 operates upon determining that the TX 100 is not in fast charge mode but is operating according to BPP or EPP. Figure 14 From F1415 in FIG. 14 , the TX 100 may operate in the case where it is determined that the TX 100 is not in the fast charge mode but is operating according to the MPP that is not the fast charge mode. In the first embodiment described above, from Figure 15 Starting with F1514 in RX200, the RX200 operates in the event that it determines that the RX200 is not in fast charge mode but is operating according to BPP or EPP. Figure 15 Starting from F1514 in

[1514] , the TX 200 may operate in a case where it is determined that the TX 200 is not in rapid charge mode but is operating according to an MPP that is not in rapid charge mode. Here, "MPP that is not in rapid charge mode" refers to a mode in which the TX 100 transmits 15 watts or less of power to the RX 200 while the MPP has the function of accurately securing the TX 100 and RX 200 in a predetermined position. Alternatively, "MPP that is not in rapid charge mode" refers to a mode in which the RX 200 receives 15 watts or less of power from the TX 100 while the MPP has the function of accurately securing the TX 100 and RX 200 in a predetermined position.

[0345] [Second embodiment]

[0346] In this embodiment, the process of the TX 100 and the RX 200 described in the first embodiment will be described as follows: Figure 14 The F1413 and the flowchart of the RX 200 Figure 15 The control executed in F1512 of the RX 200 is described below. Specifically, the control executed during operation in rapid charge mode, which is not performed according to BPP or EPP, will be described. As described above, in rapid charge mode, higher power is transferred from the TX 100 to the RX 200 compared to BPP or EPP. Therefore, the following issues arise in rapid charge mode.

[0347] The noise leaking from the power transmitting (receiving) antenna to the surrounding area is greater than the noise during operation according to BPP or EPP

[0348] ● Faster and more stable communication is expected compared to operation according to BPP or EPP

[0349] Compared with operations based on BPP or EPP, the accuracy of foreign body detection is reduced

[0350] Control performed during operation in the rapid charge mode in order to address each of the above-mentioned problems will be described in detail below.

[0351] <Noise leakage to surrounding areas>

[0352] As a first method for suppressing noise leakage from the power transmitting and receiving antennas to the surrounding area, a method for varying the power transmitted from the TX 100 to the RX 200 based on a coupling state index between the power transmitting and receiving antennas will be described. First, a method for reducing the power transmitted from the TX 100 to the RX 200 using a coupling state index between the power transmitting and receiving antennas will be described. The TX 100 and RX 200 measure and calculate the coupling state index between the power transmitting and receiving antennas. When the coupling state index between the power transmitting and receiving antennas is low (weak) relative to a predetermined threshold, this state is referred to as a weak coupling state. When the coupling state index between the power transmitting and receiving antennas is high (strong) relative to a predetermined threshold, this state is hereinafter referred to as a strong coupling state.

[0353] When the TX 100 and RX 200 recognize that they are in a weakly coupled state, they control the transmission power to limit power by reducing it compared to when they are in a strongly coupled state. The power source for the power transmitted from the TX 100 can also be a noise source. Therefore, by reducing the transmitted power, noise leakage from the power transmitting and receiving antennas to the surrounding area can be suppressed. The TX 100 control unit 101 controls the power transmitting unit 103 to set the transmitted power to a predetermined value or less. The power transmitted from the power transmitting antenna 105 is limited to a predetermined value or less.

[0354] Another method for reducing the transmitted power of the TX 100 or the received power of the RX 200 is to determine the GP through negotiation between the TX 100 and RX 200 during a renegotiation phase. The RX 200 transmits information regarding the requested load power to the TX 100. The requested load power refers to the amount of power to be output to the load and requested by the RX 200 from the TX 100. The power is consumed by the load. The load refers to a system to which power is supplied by the RX 200 or its power receiving unit. Examples of loads include the RX 200's charging unit 206 and battery 207.

[0355] On the other hand, the TX 100 has a pre-determined value for potential load power or negotiable load power. Potential load power refers to the maximum load power value (highest load power level) that the TX 100 can negotiate and output (supply) to the RX 200. Negotiable load power refers to the maximum load power value (highest load power level) that the TX 100 can negotiate and output (supply) to the RX 200 during a predetermined period or under predetermined conditions. When the requested load power value is less than the negotiable load power value, negotiation is established. The TX 100 and RX 200 set the requested load power value to the value of the GP and store this value in memory. In other words, the TX 100 receives the requested load power value from the RX 200, and when this value is less than the negotiable load power value, the TX 100 transmits an ACK to the RX 200. The TX 100 and RX 200 set the requested load power value to the value of the GP and store this value in memory.

[0356] TX 100 receives the requested load power value from RX 200. If this value is greater than the negotiable load power value, TX 100 transmits a negative acknowledgment (NAK) to RX 200. RX 200 then decreases the requested load power value and again transmits information indicating the requested load power value to TX 100. RX 200 repeats this process until RX 200 receives a positive acknowledgment (ACK) from TX 100. When RX 200 receives the positive acknowledgment (ACK) from TX 100, both TX 100 and RX 200 set the requested load power value to the GP value and store this value in memory.

[0357] By setting the GP value below a predetermined value, the power transmitted by TX 100 can be reduced, and the power received by RX 200 can be reduced. Thus, TX 100 sets the potential load power or negotiable load power below a predetermined value. Alternatively, RX 200 sets the requested load power value below a predetermined value. This control can be performed during the negotiation phase. TX 100 can switch the inverter of power transmission unit 103 from a full-bridge switching circuit to a half-bridge switching circuit.

[0358] In the above example, the operations of TX 100 and RX 200 are described when they recognize that they are in a weak coupling state. On the other hand, when a foreign object (such as a metal piece) that was present between the power transmitting and power receiving antennas is removed, or when misalignment between the power transmitting and power receiving antennas is resolved and the power transmitting and power receiving antennas are positioned facing each other in the correct position, the coupling state between the power transmitting and power receiving antennas changes from a weak coupling state to a strong coupling state. Alternatively, when the distance between the power transmitting and power receiving antennas decreases, the coupling state between the power transmitting and power receiving antennas changes from a weak coupling state to a strong coupling state. The operations will be described when the coupling state between the power transmitting and power receiving antennas changes from a weak coupling state to a strong coupling state. The TX 100 and RX 200 calculate (measure) a coupling state index using the coupling state index measurement method described above and compare the calculated coupling state index with a set threshold value.

[0359] The threshold setting method is as described above. The TX 100 and RX 200 then recognize that they are in a strongly coupled state. When the TX 100 and RX 200 recognize that they are in a strongly coupled state, the TX 100 and RX 200 execute control to increase the transmitted power of the TX 100 (and thereby increase the received power of the RX 200) compared to when the TX 100 and RX 200 are in a weakly coupled state. In this case, the transmitted power of the TX 100 can be increased (and the received power of the RX 200 can be increased) by setting the GP value to a predetermined value or higher.

[0360] Therefore, the TX 100 sets the potential load power or the negotiable load power to a predetermined value or higher. Alternatively, the RX 200 sets the requested load power to a predetermined value or higher. This control can be performed during the negotiation phase or during the renegotiation phase. The TX 100 can switch the inverter of the power transmission unit 103 from a half-bridge switching circuit to a full-bridge switching circuit.

[0361] During the power transmission phase, at predetermined timings, the TX 100 or RX 200 calculates (measures) a coupling state index using the aforementioned coupling state index measurement method and compares the calculated coupling state index with a set threshold value. The predetermined timing occurs at predetermined intervals or when the TX 100 receives a predetermined packet from the RX 200. Alternatively, the predetermined timing occurs when the RX 200 receives a predetermined packet from the TX 100. The TX 100 or RX 200 can control the transmitted power based on the coupling state determination result using the aforementioned method.

[0362] Next, as a second method for suppressing noise leakage from the power transmitting antenna and the power receiving antenna to the surrounding area, a method for TX 100 to change the frequency band of the power transmission waveform will be described. Noise occurs in the frequency band used to transmit power from the power transmitting antenna to the power receiving antenna (hereinafter referred to as the used frequency band). Harmonic noise occurs in a frequency band higher than the used frequency band. When other systems are using the frequency band where noise occurs, these systems may cause malfunctions. Therefore, when TX 100 and RX 200 are operating in fast charging mode, TX 100 and RX 200 perform control to change the used frequency band from the first frequency band to the second frequency band. By changing the frequency band of noise leaking from the power transmitting antenna and the power receiving antenna to the surrounding area, the impact on other systems can be suppressed. The used frequency band predefined in the WPC standard ranges from 87 kHz to 205 kHz. When the TX 100 and the RX 200 recognize that the TX 100 and the RX 200 operate in the fast charging mode, the TX 100 and the RX 200 change the use frequency band to a frequency band lower than 87 kHz or a frequency band higher than 205 kHz.

[0363] Next, as a third method for suppressing noise leaking from the power transmitting and receiving antennas to the surrounding area, a method using a noise suppression circuit will be described. The TX 100 or RX 200 includes a noise suppression circuit. For example, the noise suppression circuit is composed of an inductor, capacitor, resistor, filter, and noise suppression components (such as ferrite) mounted on the TX 100's circuit board and connected to the power transmitting antenna 105, the power transmitting unit 103, and the first communication unit 104. The noise suppression circuit is configured according to the frequency band used. The noise suppression circuit is composed of an inductor, capacitor, resistor, filter, and noise suppression components (such as ferrite) mounted on the RX 200's circuit board and connected to the power receiving antenna 205, the power receiving unit 203, and the first communication unit 204. The noise suppression circuit is configured according to the frequency band used. The reason for this is that the noise source is based on the power transmitted by the TX 100, and the frequency band of the noise generated is determined by the frequency band used. Therefore, the TX 100 or RX 200 has a noise suppression circuit for each frequency band used. When the TX 100 and the RX 200 operate in the quick charge mode, the TX 100 and the RX 200 perform control to suppress noise by changing the use frequency band from the first frequency band to the second frequency band and switching to a noise suppression circuit corresponding to the changed use frequency band.

[0364] Next, as a fourth method for suppressing noise leakage from the power transmitting and receiving antennas to the surrounding area, a method for changing the parameters of the frequency shift keying used by the TX 100 and RX 200 for communication will be described. A method for changing the parameters of the load modulation, amplitude modulation, or backscatter modulation used by the RX 200 and TX 100 for communication will also be described.

[0365] In communication for information transmission from the TX 100 to the RX 200, the first communication unit 104 of the TX 100 performs frequency shift keying on the electromagnetic waves output from the power transmission antenna 105. In this process, the TX 100 transmits information while changing the frequency of the carrier wave (power transmission waveform). When using two frequencies, the TX 100 associates the relatively high-frequency signal with the first information (e.g., "1") and the relatively low-frequency signal with the second information (e.g., "0"). The TX 100 transmits (transmits power) while switching between the two frequencies, and transmits information to the RX 200.

[0366] The TX 100 switches the frequency of the carrier to a first operating frequency (denoted by fop) corresponding to an unmodulated state and a second operating frequency (denoted by fmod) corresponding to a modulated state to transmit information to the RX 200. fop and fmod are defined by two parameters.

[0367] The first parameter is polarity, which indicates whether the difference between fmod and fop (fmod - fop) is positive or negative. By changing the polarity, noise in a specific frequency band can be suppressed. Noise in the frequency band used for communication or harmonic noise in frequency bands above this band can cause malfunctions in other systems. By changing the polarity, the frequency band used for communication can be changed.

[0368] The second parameter is the modulation index (frequency shift, modulation depth, depth), which indicates the magnitude (absolute value) of the difference between fmod and fop. As the modulation index increases, the magnitude of the difference between fmod and fop increases. Consequently, the bandwidth of noise in a specific frequency band leaking from the power transmitting and receiving antennas to the surrounding area widens. When the TX 100 and RX 200 operate in fast charge mode, there is a possibility of strong noise occurring over a wider bandwidth during power transmission.

[0369] Therefore, when the TX 100 and the RX 200 operate in the fast charge mode, the TX 100 and the RX 200 control the values ​​of the first parameter and the second parameter to predetermined values ​​in communication for transmitting information from the TX 100 to the RX 200 .

[0370] For example, when the TX 100 and RX 200 operate in fast charge mode, the polarity of the TX 100 and RX 200 is controlled to be negative (positive). By changing the polarity, the frequency band used for communication can be controlled. As a result, noise in a specific frequency band that leaks from the power transmitting and receiving antennas to the surrounding area can be suppressed.

[0371] When the TX 100 and RX 200 operate in fast charge mode, they control the modulation parameters (frequency shift, modulation depth, and depth) to be reduced. Since the difference between fmod and fop is reduced, the bandwidth of noise in a specific frequency band leaking from the power transmitting and receiving antennas to the surrounding area can be narrowed.

[0372] The RX 200 may incorporate the first parameter and the second parameter into a configuration data packet to be transmitted during the configuration phase. When the RX 200 recognizes that the TX 100 and the RX 200 are operating in the fast charge mode, the RX 200 sets the values ​​of the two parameters related to frequency shift keying in the configuration data packet to predetermined values ​​and transmits the packet to the TX 100. The TX 100 performs frequency shift keying based on the values ​​of the two parameters in the received packet and transmits the information to the RX 200.

[0373] The packet used by RX 200 to transmit the values ​​of the first and second parameters to TX 100 is a signal strength packet or an identification packet. Alternatively, the packet may be an extended identification packet. Alternatively, the packet may be a packet during the calibration phase or the power transfer phase, namely, RP1, RP2, or RP0. These packets are hereinafter referred to as "predetermined packets."

[0374] Next, we will describe a method for changing the parameters of load modulation, amplitude modulation, or backscatter modulation used by the RX 200 to transmit information to the TX 100. The first communication unit 204 of the RX 200 performs load modulation, amplitude modulation, or backscatter modulation on the electromagnetic waves output from the power transmission antenna 105 of the TX 100, and transmits information to the TX 100 for communication. In this case, the RX 200 transmits information while varying the amplitude of the carrier wave (power transmission waveform). When using two amplitudes, the RX 200 associates a signal with a relatively large amplitude with the first information (e.g., "1") and a signal with a relatively small amplitude with the second information (e.g., "0"). The RX 200 transmits information to the TX 100 by superimposing the signal on the power transmission waveform while switching the amplitude.

[0375] The RX 200 switches the amplitude of the carrier wave between the following two types of amplitudes to transmit information to the TX 100 .

[0376] ●Amp_A in the high state (Hi-State) (relatively large amplitude)

[0377] ●Low-State amplitude Amp_B (relatively small amplitude)

[0378] The magnitude of the difference between Amp_A and Amp_B is called the modulation depth. As the modulation depth increases, the carrier frequency changes more significantly, widening the bandwidth of noise in a specific frequency band leaking from the power transmitting and receiving antennas. Therefore, when the TX 100 and RX 200 operate in rapid charge mode, there is a possibility of strong noise occurring over a wider bandwidth during power transmission. Therefore, when the TX 100 and RX 200 operate in rapid charge mode, the TX 100 and RX 200 control the modulation depth to a predetermined value during communication from the RX 200 to the TX 100. More specifically, the TX 100 and RX 200 control the modulation depth to reduce the magnitude of the difference between the amplitudes Amp_A and Amp_B. This narrows the bandwidth of noise in a specific frequency band leaking from the power transmitting and receiving antennas to the surrounding area.

[0379] When the RX 200 performs the above-described processing, the RX 200 may notify the TX 100 of the modulation depth to be used in advance via a predetermined packet. For example, the RX 200 may incorporate information regarding the modulation depth to be used into a configuration data packet to be transmitted during the configuration phase. When the RX 200 operates in fast charge mode, the RX 200 sets the value of the parameter (modulation depth) related to load modulation, amplitude modulation, or backscatter modulation in the configuration data packet to a predetermined value and transmits the packet to the TX 100. The TX 100 controls the power transmission waveform based on the value of the parameter (modulation depth) related to load modulation, amplitude modulation, or backscatter modulation contained in the received packet. The packet used by the RX 200 to transmit information regarding the parameter (modulation depth) related to load modulation, amplitude modulation, or backscatter modulation to the TX 100 may be the predetermined packet described above.

[0380] Next, as a fifth method for suppressing noise leakage from the power transmitting and receiving antennas, a method for changing the signal modulation method used in communications related to information transmission from the TX 100 to the RX 200 and from the RX 200 to the TX 100 will be described. An example of a signal modulation method is a spread spectrum method that performs communication using a signal with a wide frequency band exceeding the frequency band required for information transmission. Specifically, direct sequence spread spectrum (DSSS) is a first method.

[0381] For example, to operate in fast charging mode, the first communication unit 104 of the TX 100 calculates the original signal after frequency shift keying using a spreading signal called a spreading code (PN: pseudo-noise) or pseudo-random noise. A first method involves directly spreading the energy over a wider frequency band than that required to transmit the original signal. The TX 100 transmits the calculated signal to the RX 200. The RX 200 previously stores the data of the spread signal used by the TX 100 for calculation in the memory 208. The RX 200 inverse-transforms the received signal using the spread signal to obtain the original signal after frequency shift keying. When the TX 100 and the RX 200 are identified as operating in fast charging mode during transmission from the RX 200 to the TX 100, the following processing is performed. In other words, the first communication unit 204 of the RX 200 calculates the original signal after load modulation, amplitude modulation, or backscatter modulation using the spread signal. The RX 200 transmits the calculated signal to the TX 100. TX 100 stores the data of the spread signal used by RX 200 in calculations in memory 106. Using the spread signal, TX 100 inversely transforms the received signal to obtain the original signal after load modulation, amplitude modulation, or backscatter modulation. Using the first method reduces the magnitude (level) of noise in a specific frequency band leaking from the power transmitting and receiving antennas to the surrounding area.

[0382] The second method is frequency hopping spread spectrum (FHSS). This method divides the frequency band allocated for communication into multiple frequency slots and quickly switches the frequency slots used for communication in a short time according to the pattern of switching frequencies. In other words, transmission is performed by using different frequency bands within a wide frequency band during the period of switching frequency bands in a short time. Frequency slots are also called "hopping channels". The pattern of switching frequencies is called a hopping sequence or hopping pattern. TX 100 and RX 200 can receive signals in their respective frequency bands and obtain the original signal according to the pre-acquired hopping sequence.

[0383] For example, in transmission from TX 100 to RX 200, when TX 100 and RX 200 operate in the fast charge mode, the first communication unit 104 of TX 100 performs processing of the original signal after transmission frequency shift keying by using a frequency slot according to a frequency hopping sequence.

[0384] TX 100 transmits the processed signal to RX 200. RX 200 previously stores the data of the frequency hopping sequence used for processing by TX 100 in memory 208. RX 200 inverse-transforms the received signal according to the frequency hopping sequence to obtain the original signal after frequency shift keying. To operate in fast charging mode, first communication unit 204 of RX 200 performs processing for transmitting the original signal after load modulation, amplitude modulation, or backscatter modulation using frequency slots according to the frequency hopping sequence. RX 200 transmits the processed signal to TX 100. TX 100 previously stores the data of the frequency hopping sequence used for processing by RX 200 in memory 106. TX 100 inverse-transforms the received signal according to the frequency hopping sequence to obtain the original signal after load modulation, amplitude modulation, or backscatter modulation. By using the second method, the magnitude (level) of noise in a specific frequency band leaking from the power transmitting antenna and the power receiving antenna can be reduced.

[0385] The third method is a method of performing direct sequence spread spectrum processing and also performing frequency hopping spread spectrum processing. By combining these two methods, the magnitude (level) of noise in a specific frequency band leaking from the power transmitting antenna and the power receiving antenna can be further reduced.

[0386] In the first to third methods, information indicating which method is used or which method is supported may be incorporated into a configuration packet transmitted by the RX 200 during the configuration phase. When the TX 100 and the RX 200 are operating in the fast charge mode, the RX 200 stores data (e.g., "1") indicating the use of any of the first to third methods in a predetermined field of the configuration packet. Alternatively, a "1" corresponding to the use of the first method, a "2" corresponding to the use of the second method, or a "3" corresponding to the use of the third method may be stored in the relevant field. When the RX 200 recognizes that the TX 100 and the RX 200 are not operating in the fast charge mode, the RX 200 stores a "0" in the relevant field because none of the first to third methods are used. Alternatively, information indicating whether the RX 200 supports any of the first to third methods is stored in a predetermined field. When the RX 200 supports a certain method, the RX 200 stores a "1" as data in the relevant field; when the RX 200 does not support a certain method, the RX 200 stores a "0" as data in the relevant field. Having received the configuration packet from the RX 200, the TX 100 transmits information to and receives information from the RX 200 based on the information related to the modulation method in the packet. The packet used to transmit information indicating which of the first to third methods the RX 200 uses for the TX 100 or which of the first to third methods the RX 200 supports may be the predetermined packet described above.

[0387] In the first to third methods, information indicating which method is used or which method is supported may be incorporated into the following packet. This packet is a power transmitter capability (CAP) packet or a power transmitter identification (ID) packet to be transmitted by the TX 100. For example, the TX 100 stores data (e.g., "1") indicating that any of the first to third methods is used in a predetermined field of the power transmitter capability (CAP) packet. Similarly, when a power transmitter identification (ID) packet is used, data (e.g., "1") indicating that any of the first to third methods is used is similarly stored in a predetermined field. Alternatively, a "1" corresponding to the use of the first method, a "2" corresponding to the use of the second method, or a "3" corresponding to the use of the third method is stored in the relevant field. When the TX 100 and the RX 200 are not operating in the fast charging mode, the RX 200 stores a "0" in the relevant field because none of the first to third methods is used. Alternatively, information indicating whether the TX 100 supports any of the first to third methods is stored in a predetermined field. If the TX 100 supports a method, the TX 100 stores "1" in the relevant field as data; if the TX 100 does not support a method, the RX 200 stores "0" in the relevant field as data. The RX 200, having received a power transmitter CAP packet or a power transmitter ID packet, transmits and receives information to and from the TX 100 according to the modulation method specified in the packet.

[0388] When the RX 200 performs the above-described processing, the RX 200 may notify the TX 100 of the modulation method to be used in advance via a predetermined packet. For example, the RX 200 may incorporate information regarding the modulation method to be used into a configuration data packet transmitted during the configuration phase. When the RX 200 and the TX 100 are operating in the fast charge mode, the RX 200 sets a predetermined value in a field in the packet indicating the modulation method to be used by the RX 200 and transmits the packet to the TX 100. The TX 100 transmits information to and receives information from the RX 200 based on the information regarding the modulation method to be used by the RX 200 contained in the received packet.

[0389] When the TX 100 performs the above-described processing, the TX 100 may notify the RX 200 of the modulation method used in advance via a predetermined packet. For example, information regarding the modulation method used may be incorporated into a power transmitter CAP packet or a power transmitter ID packet to be transmitted by the TX 100. When the TX 100 and the RX 200 are operating in the fast charging mode, the TX 100 sets a predetermined value in a field in the packet indicating the modulation method used by the TX 100 and transmits the packet to the RX 200. The RX 200 transmits information to and receives information from the TX 100 based on the information regarding the modulation method used by the TX 100 contained in the received packet.

[0390] Using the above method, the RX 200 notifies the TX 100 of information related to the modulation method to be used in advance via a predetermined packet. Based on this information, the TX 100 and RX 200 can then negotiate with each other through communication and determine the modulation method to be used for communication. Alternatively, using the above method, the TX 100 notifies the RX 200 of information related to the modulation method to be used in advance via a predetermined packet. Based on this information, the TX 100 and RX 200 can then negotiate with each other through communication and determine the modulation method to be used for communication.

[0391] Next, as a sixth method for suppressing noise leakage from the power-transmitting and power-receiving antennas to the surrounding area, a method in which the TX 100 switches the power-transmitting antenna (power-transmitting coil) will be described. When the TX 100 and RX 200 operate in fast charging mode, the TX 100 transmits high-power electricity to the RX 200, increasing the noise leakage to the surrounding area. Furthermore, one factor contributing to this noise increase is a significant size difference between the power-transmitting and power-receiving antennas. For example, consider a case where the power-transmitting antenna is larger than the power-receiving antenna. In this case, because the power-receiving antenna is relatively small, a portion of the magnetic flux generated by the power-transmitting antenna during power transmission from the TX 100 to the RX 200 does not pass through the interior of the power-receiving antenna. As the size difference between the power-transmitting and power-receiving antennas increases, the leakage magnetic flux increases. To address this situation, the TX 100 includes two or more power-transmitting antennas. For example, of the two power-transmitting antennas, the larger one is referred to as the "power-transmitting antenna (large)" and the smaller one is referred to as the "power-transmitting antenna (small)."

[0392] Assume that the TX 100 selects the power-transmitting antenna (large), measures and calculates the coupling state index between the power-transmitting antenna and the power-receiving antenna using the above-described method, and compares the coupling state index with a threshold value to determine that the coupling state is a weak coupling state. In this case, the TX 100 selects the power-transmitting antenna (small). The TX 100 then measures and calculates the coupling state index between the power-transmitting antenna and the power-receiving antenna using the above-described method, and again compares the coupling state index with the threshold value to determine whether the coupling state is a weak coupling state. As a result of this determination, it is assumed that the coupling between the power-transmitting antenna and the power-receiving antenna is stronger than when the power-transmitting antenna (large) was selected. In this case, the TX 100 is controlled to use the power-transmitting antenna (small) during each subsequent phase.

[0393] Assume that the TX 100 first selects the power-transmitting antenna (small), measures and calculates the coupling state index between the power-transmitting antenna and the power-receiving antenna using the above-described method, and compares the coupling state index with a threshold value to determine that the coupling state is a weak coupling state. In this case, the TX 100 selects the power-transmitting antenna (large). Then, the TX 100 measures and calculates the coupling state index between the power-transmitting antenna and the power-receiving antenna using the above-described method, and again compares the coupling state index with the threshold value to determine whether the coupling state is a weak coupling state. As a result of this determination, it is assumed that the coupling between the power-transmitting antenna and the power-receiving antenna is stronger than when the power-transmitting antenna (small) was selected. In this case, the TX 100 is controlled to use the power-transmitting antenna (large) during each subsequent stage.

[0394] The TX 100 may include three or more power-transmitting antennas of different sizes. The TX 100 measures the coupling state between the power-transmitting and power-receiving antennas when using each power-transmitting antenna and makes a determination. During each subsequent phase, the TX 100 is controlled to use the power-transmitting antenna with the best coupling state.

[0395] Alternatively, as shown in the first method, RX 200 notifies TX 100 of detailed information regarding the power receiving device's hardware via a predetermined packet. More specifically, RX 200 notifies TX 100 of information such as the size and type of the power receiving antenna (power receiving coil). TX 100 receives the predetermined packet from RX 200 and, based on information such as the size and type of the power receiving antenna (power receiving coil), selects the power transmitting antenna determined to be optimal for the target power receiving antenna. TX 100 or RX 200 measures a coupling status indicator between the power transmitting antenna and the power receiving antenna and determines whether a value indicating the coupling status (e.g., a k value) is greater than or equal to a threshold. During each subsequent stage, TX 100 is controlled to use the power transmitting antenna selected based on the determination result, which exhibits a favorable coupling status.

[0396] Next, as a seventh method for suppressing noise leakage from the power transmitting and receiving antennas to the surrounding area, a method will be described in which the power transmission-related circuits, including the power transmitting antennas, are modified to increase the quality factor of the circuits. The power transmission efficiency from the TX 100 to the RX 200 is expressed as the product of the coupling coefficient k and the quality factor (Q factor). When the TX 100 and RX 200 operate in the rapid charge mode, a decrease in the transmission efficiency can be suppressed by performing control to increase the value of the quality factor. When the TX 100 and RX 200 operate in the rapid charge mode, the TX 100 (or RX 200) modifies the power transmission-related circuits, including the power transmitting antenna (or the power receiving antenna), to increase the quality factor of the circuits. Specifically, a first control is performed to switch the power transmitting antenna 105 (or the power receiving antenna 205) to a power transmitting antenna (or the power receiving antenna) having a different size or a different inductance value.

[0397] Alternatively, a second control is performed to switch the resonant capacitor 107 (or resonant capacitor 211) to a resonant capacitor having a different constant. Alternatively, a third control is performed to connect a new, different capacitor or inductor to the power transmitting antenna 105 (or power receiving antenna 205) or the resonant capacitor 107 (or resonant capacitor 211). All of the first, second, and third controls may be performed, or at least one may be performed. The first, second, and third controls may be performed at the timing when the RX 200, having recognized that the TX 100 and RX 200 are operating in the fast charge mode, notifies the TX 100 using a packet. Alternatively, the TX 100, having recognized that the TX 100 and RX 200 are operating in the fast charge mode, may perform the first, second, and third controls at the timing when the TX 100 notifies the RX 200 using a predetermined packet.

[0398] <Communication>

[0399] Next, we will describe a first method for suppressing communication instability between the TX 100 and RX 200. When the TX 100 and RX 200 operate in rapid charge mode, they need to perform rapid control to enhance transmission efficiency. Therefore, stable communication is desirable for the communication in which the TX 100 and RX 200 perform control. Therefore, we will describe methods for stabilizing communication. Specifically, we will describe a first method for changing the parameters of frequency shift keying used to transmit signals from the TX 100, and a second method for changing the parameters of load modulation, amplitude modulation, or backscatter modulation used to transmit signals from the RX 200.

[0400] Initially, in the first modification method, the parameters of frequency shift keying are modulation indices (frequency shift, modulation depth, and depth), which indicate the magnitude of the difference between fmod and fop. As the modulation indices increase, the magnitude of the difference between fmod and fop increases, making it easier for the RX 200 to demodulate signals received from the TX 100. Therefore, when the TX 100 and RX 200 operate in fast charge mode, the TX 100 and RX 200 control the communication so that the modulation indices become a predetermined value when information is transmitted from the TX 100 to the RX 200. More specifically, when the TX 100 and RX 200 operate in fast charge mode, the TX 100 and RX 200 control the communication so that the modulation indices become larger than when operating in accordance with BPP or EPP, making it easier for the RX 200 to demodulate signals received from the TX 100.

[0401] The modulation index may be incorporated into a configuration data packet transmitted by the RX 200 during the configuration phase. When the RX 200 recognizes that the TX 100 and the RX 200 are operating in the fast charge mode, the RX 200 sets the modulation index in the configuration data packet to a predetermined value and transmits the packet to the TX 100. The TX 100 transmits information from the TX 100 to the RX 200 based on the modulation index included in the received packet. The packet used by the RX 200 to transmit the information related to the modulation index to the TX 100 may be the predetermined packet described above.

[0402] Next, the second changing method will be described. As described above, for example, RX 200 transmits information to TX 100 while switching the amplitude of the carrier wave between a relatively large amplitude Amp_A and a relatively small amplitude Amp_B. As the modulation depth increases, corresponding to the difference between Amp_A and Amp_B, it becomes easier for TX 100 to demodulate the signal transmitted by RX 200. Therefore, when TX 100 and RX 200 operate in rapid charge mode, TX 100 and RX 200 control the modulation depth of amplitude modulation or load modulation to a predetermined value in communications used to transmit information from RX 200 to TX 100. More specifically, when TX 100 and RX 200 operate in rapid charge mode, TX 100 and RX 200 control the modulation depth to increase compared to a case where TX 100 and RX 200 operate according to BPP or EPP. As a result, the difference between the amplitude Amp_A in the high state and the amplitude Amp_B in the low state increases, and thus the TX 100 easily demodulates the signal transmitted by the RX 200 .

[0403] When the RX 200 performs the above processing, the RX 200 may notify the TX 100 of the modulation depth to be used in advance through a predetermined packet. This has been described above, and the predetermined packet for transmitting the modulation depth is also similar, so its description is omitted.

[0404] Next, a method for changing the communication method associated with communication between the TX 100 and RX 200 will be described. To enable the TX 100 and RX 200 to perform high-speed control, communication between the TX 100 and RX 200 needs to be enhanced to a faster method. Therefore, when the TX 100 and RX 200 recognize that they are operating in fast charging mode, the TX 100 and RX 200 control the communication method to change. Control is performed between the second communication unit 109 of the TX 100 and the second communication unit 212 of the RX 200 to change to a communication method based on a standard other than the WPC standard. Wireless LAN, BLE, and NFC are listed as communication methods. The second communication unit 109 of the TX 100 communicates with the RX 200 using an antenna different from the power transmitting antenna 105. The second communication unit 212 of the RX 200 communicates with the TX 100 using an antenna different from the power receiving antenna 205. The frequency band used for communication by the second communication unit 109 or the second communication unit 212 is different from the frequency band used for power transmission. In this way, when the TX 100 and the RX 200 operate in the fast charging mode, the TX 100 and the RX 200 can perform stable communication by using a communication method different from the communication method using the power transmitting antenna 105 and the power receiving antenna 205.

[0405] The RX 200 may include information regarding whether it supports communication methods based on standards other than the WPC standard in a configuration data packet transmitted during the configuration phase. Alternatively, the RX 200 may include data indicating which communication method based on standards other than the WPC standard is used in the configuration data packet. For example, when the RX 200 recognizes that the RX 200 is operating in fast charging mode, the RX 200 stores data (e.g., "1") indicating the use of a communication method based on a standard other than the WPC standard in a predetermined field of the configuration data packet. Alternatively, a "1" corresponding to the use of wireless LAN or a "2" corresponding to the use of BLE may be stored in the relevant field. A "3" corresponding to the use of NFC may also be stored in the relevant field. When the TX 100 and RX 200 are not operating in fast charging mode (i.e., when the TX 100 and RX 200 are operating according to BPP or EPP), a "0" corresponding to the non-use of a communication method based on a standard other than the WPC standard is stored in the relevant field. Alternatively, information indicating whether RX 200 supports any communication methods is stored in a predetermined field. If RX 200 supports a communication method, RX 200 stores "1" in the field as data; if RX 200 does not support the method, RX 200 stores "0" in the relevant field as data. RX 200 then transmits the packet to TX 100.

[0406] Based on the information on the communication method included in the received configuration packet, TX 100 transmits information from TX 100 to RX 200. The packet used by RX 200 to transmit information indicating whether RX 200 supports a communication method based on a standard other than the WPC standard to TX 100 may be the predetermined packet described above.

[0407] When the RX 200 performs the above-described processing, the RX 200 may notify the TX 100 of the communication method to be used in advance via a predetermined packet. For example, the RX 200 may include information regarding the communication method to be used in a configuration data packet transmitted during the configuration phase. When the RX 200 recognizes that the RX 200 and the TX 100 are operating in the fast charge mode, the RX 200 sets a predetermined value in the field indicating the communication method to be used by the RX 200 in the packet and transmits the packet to the TX 100. The TX 100 determines the communication method to be used based on the information regarding the communication method to be used by the RX 200 contained in the received packet. The packet used by the RX 200 to transmit the information regarding the communication method to the TX 100 may be the predetermined packet described above.

[0408] TX 100 may include information indicating whether TX 100 supports communication methods based on standards other than WPC, or data indicating which communication method based on standards other than WPC is used, in a predetermined packet. For example, when TX 100 recognizes that TX 100 and RX 200 are operating in fast charging mode, TX 100 stores data (e.g., "1") indicating the use of a communication method based on a standard other than WPC in a field of the predetermined packet. Alternatively, a "1" corresponding to the use of wireless LAN or a "2" corresponding to the use of BLE may be stored in the relevant field. A "3" corresponding to the use of NFC may also be stored in the relevant field. When TX 100 and RX 200 are not operating in fast charging mode (i.e., when TX 100 and RX 200 are operating according to BPP or EPP), a "0" corresponding to the non-use of a communication method based on a standard other than WPC is stored in the relevant field. TX 100 then transmits the packet to RX 200. Alternatively, information indicating whether TX 100 supports any communication methods is stored in a predetermined field. When TX 100 supports a communication method, TX 100 stores "1" as data in the relevant field; when TX 100 does not support a method, TX 100 stores "0" as data in the relevant field. RX 200 transmits information from RX 200 to TX 100 based on the information related to the communication method contained in the received predetermined packet.

[0409] When the TX 100 performs the above-described processing, the TX 100 may notify the RX 200 of the communication method used in advance through a predetermined packet. When the TX 100 recognizes that the TX 100 and the RX 200 are operating in the fast charge mode, the TX 100 sets a predetermined value in the field indicating the communication method used by the TX 100 in the packet and transmits the packet to the RX 200.

[0410] The RX 200 determines the communication method based on the information on the communication method used by the TX 100 contained in the received packet.

[0411] <Foreign matter detection accuracy>

[0412] Next, we will describe a first method for improving the accuracy of detecting foreign matter between the TX 100 and RX 200. When the TX 100 and RX 200 operate in rapid charging mode, the accuracy of foreign matter detection using the quality factor measurement method and power loss method predefined in the WPC standard may decrease. Therefore, when the TX 100 and RX 200 operate in rapid charging mode, the TX 100 and RX 200 use a foreign matter detection method other than the one predefined in the WPC standard.

[0413] As a first foreign object detection method other than the foreign object detection method predefined in the WPC standard, a method for detecting foreign objects based on the coupling state between the power-transmitting and power-receiving antennas will be described. When a weak coupling state is identified, the presence of foreign objects can be detected based on the coupling state between the power-transmitting and power-receiving antennas. As described in the coupling state index measurement method, the TX 100 and RX 200 measure the coupling state index between the power-transmitting and power-receiving antennas and perform foreign object detection based on the measured value. The method for setting a threshold value related to the likelihood of the presence of foreign objects has already been described. In the case of a weak coupling state, the likelihood of the presence of foreign objects can be determined with higher accuracy based on the measurement results of the coupling state index between the power-transmitting and power-receiving antennas. Measuring the coupling state index between the power-transmitting and power-receiving antennas and determining the likelihood of the presence of foreign objects can be performed periodically. In performing foreign object detection based on the coupling state index measurement results, the TX 100 and RX 200 can combine the quality factor measurement method, the power loss method, and the waveform attenuation method. The method for setting the threshold value for each method is described above.

[0414] For example, if the entity performing foreign object detection processing based on the measurement results of the coupling state index between the power-transmitting and power-receiving antennas is TX 100, TX 100 performs foreign object detection processing based on the measurement results of the coupling state index between the power-transmitting and power-receiving antennas and obtains a judgment result. The judgment result is, for example, "high probability of foreign object presence," "foreign object presence," "low probability of foreign object presence," or "no foreign object presence," and TX 100 notifies RX 200 of the judgment result. If the judgment result is "high probability of foreign object presence" or "foreign object presence," RX 200 transmits a packet requesting execution of the predetermined foreign object detection processing to TX 100. Alternatively, if the judgment result is "high probability of foreign object presence" or "foreign object presence," TX 100 transmits a packet requesting transmission of a packet requesting execution of the predetermined foreign object detection processing to RX 200. Upon receiving the packet, RX 200 transmits a packet requesting execution of the predetermined foreign object detection processing to TX 100. The predetermined foreign object detection process refers to all foreign object detection processes based on the quality factor measurement method, the power loss method, and the waveform attenuation method, or one or more of these foreign object detection processes. TX 100 performs the predetermined foreign object detection process based on a request from RX 200 and notifies RX 200 of the judgment result. When the judgment result is "the possibility of the presence of a foreign object is high" or "the presence of a foreign object", RX 200 transmits a packet to TX 100 requesting the restriction of power transmission. For example, the packet is a packet requesting that the GP value be set to a low value, and RP1 and RP2 requesting the CAL process of the power loss method again. Alternatively, the packet is a packet requesting the CAL process using the waveform attenuation method or the coupling state index measurement method again. Alternatively, the packet is an EPT packet requesting the suspension of power transmission.

[0415] The aforementioned predetermined foreign object detection process is performed, and the TX 100 notifies the RX 200 of the determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet to the TX 100 requesting foreign object detection based on the coupling state between the power transmitting and receiving antennas. Having received the packet, the TX 100 performs foreign object detection based on the coupling state between the power transmitting and receiving antennas and notifies the RX 200 of the determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet to the TX 100 requesting power transmission restriction. For example, this packet may be a packet requesting to set the GP value to a low value, and RP1 and RP2 requesting the power loss method's CAL process again. Alternatively, this packet may be a packet requesting the waveform decay method's CAL process again. Alternatively, this packet may be an EPT packet requesting the suspension of power transmission.

[0416] Alternatively, if the entity performing foreign object detection processing based on the measurement results of the coupling state indicator between the power transmitting and power receiving antennas is the RX 200, the RX 200 executes the foreign object detection processing and obtains a judgment result. The judgment result can be "high probability of foreign object presence," "foreign object present," "low probability of foreign object presence," or "no foreign object present," and the RX 200 notifies the TX 100 of the judgment result. If the judgment result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet to the TX 100 requesting execution of a predetermined foreign object detection process. The predetermined foreign object detection process refers to any foreign object detection process based on the quality factor measurement method, the power loss method, or the waveform attenuation method, or one or more of these foreign object detection processes. The TX 100 executes the predetermined foreign object detection process in response to the request from the RX 200 and notifies the RX 200 of the judgment result. If the judgment result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet to the TX 100 requesting power transmission restriction. For example, this packet may request that the GP value be set to a low value, and may also request RP1 and RP2 to re-request CAL processing using the power loss method. Alternatively, this packet may request CAL processing using the waveform decay method or the coupling state index measurement method. Alternatively, this packet may be an EPT packet requesting that power transmission be stopped.

[0417] The aforementioned predetermined foreign object detection process is performed, and the TX 100 notifies the RX 200 of the determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet notifying the TX 100 that foreign object detection processing is being performed based on the coupling state between the power transmitting and receiving antennas. The RX 200 transmits this packet, performs foreign object detection processing based on the coupling state between the power transmitting and receiving antennas, and notifies the TX 100 of the determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet requesting power transmission restriction to the TX 100. For example, this packet may be a packet requesting that the GP value be set to a low value, and RP1 and RP2 requesting the power loss method's CAL process again. Alternatively, this packet may be a packet requesting the waveform decay method's CAL process again. Alternatively, this packet may be an EPT packet requesting the suspension of power transmission.

[0418] The above example describes an operation in which the TX 100 or RX 200 performs foreign object detection processing based on the measurement results of the coupling state index between the power transmitting antenna and the power receiving antenna, and a predetermined foreign object detection processing at different timings. The TX 100 or RX 200 may perform one or more of the foreign object detection processing based on the measurement results of the coupling state index between the power transmitting antenna and the power receiving antenna, and the predetermined foreign object detection processing at the same timing. When the RX 200 specifies the timing, the RX 200 transmits a predetermined packet to the TX 100 to notify the TX 100 of the timing. When the TX 100 specifies the timing, the TX 100 transmits a predetermined packet to the RX 200 to notify the RX 200 of the timing. For example, when the TX 100 or RX 200 receives the predetermined packet, the TX 100 or RX 200 performs foreign object detection processing based on the measurement results of the coupling state index between the power transmitting antenna and the power receiving antenna, and foreign object detection processing using the power loss method. Alternatively, when the TX 100 or RX 200 receives a predetermined packet, the TX 100 or RX 200 performs foreign object detection processing based on the measurement result of the coupling state index between the power transmitting antenna and the power receiving antenna, and foreign object detection processing using the waveform attenuation method. Alternatively, when the TX 100 or RX 200 receives a predetermined packet, the TX 100 or RX 200 performs foreign object detection processing based on the measurement result of the coupling state index between the power transmitting antenna and the power receiving antenna, foreign object detection processing using the power loss method, and foreign object detection processing using the waveform attenuation method.

[0419] Alternatively, the TX 100 or RX 200 may execute one or more of the predetermined foreign object detection processes at the same timing. When the RX 200 specifies the timing, the RX 200 transmits a predetermined packet to the TX 100 to notify the TX 100 of the timing. When the TX 100 specifies the timing, the TX 100 transmits a predetermined packet to the RX 200 to notify the RX 200 of the timing. For example, when the TX 100 or RX 200 receives the predetermined packet, the TX 100 or RX 200 executes the foreign object detection process using the waveform attenuation method. Alternatively, when the TX 100 or RX 200 receives the predetermined packet, the TX 100 or RX 200 executes the foreign object detection process using the power loss method and the foreign object detection process using the waveform attenuation method.

[0420] Next, as a second method for improving the accuracy of detecting foreign objects between the TX 100 and RX 200, a method for detecting foreign objects based on the temperature of the TX 100 or RX 200 will be described. It is assumed that the TX 100 and RX 200 each have multiple temperature sensors. Specifically, the temperature sensors are placed at a higher density on the power transmitting antenna 105, charging base 300, and power receiving antenna 205 than elsewhere. This allows for higher accuracy detection of foreign objects between the TX 100 and RX 200.

[0421] When the TX 100 or RX 200 recognizes that the TX 100 and RX 200 are operating in rapid charge mode, the TX 100 or RX 200 performs foreign object detection processing based on the detected temperature. The TX 100 acquires the detection value of the temperature sensor at a predetermined timing. The predetermined timing occurs at predetermined intervals or when the TX 100 receives a predetermined packet from the RX 200. When the detection value of the temperature sensor exceeds a predetermined threshold, the TX 100 determines that there is a high probability of foreign object presence. The TX 100 calculates the rate of increase in temperature based on the multiple temperature detection values ​​acquired at the predetermined timing. When the rate of increase in temperature exceeds the predetermined threshold, the TX 100 determines that there is a high probability of foreign object presence. The determination result is notified to the RX 200 via a predetermined packet. Alternatively, upon acquiring the determination result, the TX 100 executes control for limiting the transmitted power (reducing the power) or for stopping power transmission. Since these controls have already been described, their description is omitted.

[0422] Next, the foreign object detection process based on the temperature of the RX 200 will be described. The RX 200 acquires the detection value of the temperature sensor at a predetermined timing. The predetermined timing occurs at predetermined intervals or when the RX 200 receives a predetermined packet from the TX 100. When the detection value of the temperature sensor is greater than a predetermined threshold, the RX 200 determines that "there is a high possibility of foreign object presence." The RX 200 calculates the rate of increase of the temperature based on the multiple temperature detection values ​​acquired at the predetermined timing. When the rate of increase of the temperature is greater than the predetermined threshold, the RX 200 determines that there is a high possibility of foreign object presence. The judgment result is notified to the TX 100 via a predetermined packet. Alternatively, when the judgment result is acquired, the RX 200 transmits a predetermined packet to the TX 100 to execute a process for requesting the above-mentioned power transmission to be limited (power reduction) or stopped.

[0423] Thus, using the second method, when TX 100 or RX 200 recognizes that TX 100 or RX 200 is operating in fast charge mode, TX 100 or RX 200 measures the temperature of TX 100 or RX 200 and can perform foreign object detection with higher accuracy based on the measurement result. When performing foreign object detection, TX 100 or RX 200 can combine the quality factor measurement method, the power loss method, and the waveform attenuation method. For example, when the entity performing temperature-based foreign object detection processing is TX 100, TX 100 performs temperature-based foreign object detection processing and notifies RX 200 of the foreign object determination result. If the determination result is "high probability of foreign object presence" or "foreign object presence", RX 200 provides TX 100 with a notification packet requesting execution of foreign object detection processing based on one or more of the quality factor measurement method, the power loss method, and the waveform attenuation method. TX 100 executes a predetermined foreign object detection process in response to a request from RX 200 and notifies RX 200 of the result. If the foreign object detection process determines that "there is a high probability of a foreign object present" or "there is a foreign object present," RX 200 transmits a packet to TX 100 requesting power transmission restriction. This packet, for example, may request setting the GP value to a low value, or re-request RP1 and RP2 for the power loss method's CAL process. Alternatively, this packet may request re-request CAL for the waveform attenuation method or the coupling state index measurement method. Alternatively, this packet may be an EPT packet requesting the suspension of power transmission.

[0424] Alternatively, the TX 100 performs foreign object detection based on one or more of the quality factor measurement method, the power loss method, and the waveform attenuation method, and notifies the RX 200 of the determination results. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet to the TX 100 requesting foreign object detection based on the TX 100 temperature. Based on this packet, the TX 100 obtains the TX 100 temperature detection value, performs foreign object detection, and notifies the RX 200 of the determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet to the TX 100 requesting power transmission restriction. This packet, for example, may request setting the GP value to a low value, or RP1 or RP2 requesting re-requesting the CAL process for the power loss method. Alternatively, this packet may request re-requesting the CAL process for the waveform attenuation method or the CAL process for the coupling state index measurement method. Alternatively, this packet may be an EPT packet requesting the suspension of power transmission.

[0425] Alternatively, for example, if the entity executing the temperature-based foreign object detection process is the RX 200, the RX 200 executes the temperature-based foreign object detection process and notifies the TX 100 of the foreign object determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 notifies the TX 100 of a packet requesting execution of foreign object detection processing based on one or more of the quality factor measurement method, the power loss method, and the waveform attenuation method. The TX 100 executes the predetermined foreign object detection process in response to the request from the RX 200 and notifies the RX 200 of the determination result. If the determination result of the foreign object detection process is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet requesting power transmission restriction to the TX 100. This packet, for example, requests setting the GP value to a low value, or re-requests RP1 and RP2 for the power loss method's CAL process. Alternatively, this packet requests re-requests CAL processing for the waveform attenuation method or the coupling state index measurement method. Alternatively, the packet is an EPT packet requesting to stop power transmission.

[0426] Alternatively, the TX 100 performs foreign object detection based on one or more of the quality factor measurement method, the power loss method, and the waveform attenuation method, and notifies the RX 200 of the determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 acquires the RX 200 temperature detection value to perform foreign object detection and notifies the TX 100 of the determination result. If the determination result is "high probability of foreign object presence" or "foreign object present," the RX 200 transmits a packet to the TX 100 requesting power transmission restriction. This packet, for example, may be a packet requesting to set the GP value to a low value, or RP1 or RP2 requesting the power loss method's CAL process again. Alternatively, this packet may be a packet requesting the waveform attenuation method's CAL process again or the coupling state index measurement method's CAL process again. Alternatively, this packet may be an EPT packet requesting the suspension of power transmission.

[0427] The above example describes an operation in which the TX 100 or RX 200 performs temperature-based foreign object detection processing and performs foreign object detection processing based on one or more of the quality factor measurement method, power loss method, and waveform attenuation method at different timings. The TX 100 or RX 200 can perform temperature-based foreign object detection processing and foreign object detection processing based on one or more of the quality factor measurement method, power loss method, and waveform attenuation method at the same timing. When the RX 200 specifies the timing, the RX 200 transmits a predetermined packet to the TX 100 to notify the TX 100 of the timing. When the TX 100 specifies the timing, the TX 100 transmits a predetermined packet to the RX 200 to notify the RX 200 of the timing. For example, when the TX 100 or RX 200 receives the above predetermined packet, the TX 100 or RX 200 performs temperature-based foreign object detection processing and foreign object detection processing using the power loss method.

[0428] Alternatively, when the TX 100 or RX 200 receives the above-mentioned predetermined packet, the TX 100 or RX 200 performs the foreign object detection process based on temperature and the foreign object detection process using the waveform attenuation method. Alternatively, when the TX 100 or RX 200 receives the above-mentioned predetermined packet, the TX 100 or RX 200 performs the foreign object detection process based on temperature, the foreign object detection process using the power loss method, and the foreign object detection process using the waveform attenuation method.

[0429] In the second method described above, when the TX 100 or RX 200 recognizes that the TX 100 or RX 200 is operating in fast charging mode, the TX 100 or RX 200 measures the temperature of the TX 100 or RX 200 and, based on the measurement result, performs foreign object detection with higher accuracy. Instead of the aforementioned "temperature," other physical quantities of the TX 100 or RX 200 can be measured, and foreign object detection can be performed with higher accuracy based on the measurement result. For example, the aforementioned "temperature of the TX 100" can be replaced with the following parameters of the TX 100. This parameter can be any one of the inverter input voltage, inverter input current, power supplied to the inverter, inverter output voltage, inverter output current, and power output from the inverter. Alternatively, this parameter can be any one of the voltage applied to the power transmitting antenna, current flowing through the power transmitting antenna, and power supplied to the power transmitting antenna. Alternatively, the aforementioned "temperature of the RX 200" can be replaced with the following parameters of the RX 200. This parameter can be any of the rectifier output voltage, rectifier output current, power supplied to the rectifier, power output from the rectifier, voltage applied to the power receiving antenna, current flowing through the power receiving antenna, and power received by the power receiving antenna. This parameter can be any of the voltage applied to the load (charging unit, battery), current flowing through the load (charging unit, battery), and power supplied to the load (charging unit, battery).

[0430] When these physical quantities are greater than the corresponding predetermined thresholds, the TX 100 or RX 200 determines that “abnormality exists.” When these physical quantities are less than the corresponding predetermined thresholds, the TX 100 or RX 200 determines that “abnormality does not exist.”

[0431] Next, we will describe a third method for suppressing a decrease in detection accuracy for foreign objects between the TX 100 and RX 200. As described above, there are foreign object detection methods based on quality factor measurement, power loss, waveform attenuation, the coupling state between the power transmitting and receiving antennas, and the temperature of the TX 100 or RX 200. Regardless of the method used, foreign object detection can be performed by setting a predetermined threshold.

[0432] For example, assume there is no foreign object between the TX 100 and RX 200, and there is no misalignment between the power transmitting and receiving antennas. In this situation, there is a possibility that the quality factor, power loss, waveform attenuation index, coupling state index, and temperature measured for executing the corresponding foreign object detection method will differ between when the TX 100 and RX 200 are operating in rapid charge mode and when they are operating according to BPP or EPP. In other words, control needs to be implemented so that the judgment threshold for foreign object detection differs between when the TX 100 and RX 200 are operating in rapid charge mode and when they are operating according to BPP or EPP. When TX 100 and RX 200 recognize that TX 100 and RX 200 operate in the fast charge mode, TX 100 and RX 200 set the determination threshold to the first threshold; however, when TX 100 and RX 200 recognize that TX 100 and RX 200 operate according to BPP or EPP, TX 100 and RX 200 set the determination threshold to the second threshold.

[0433] In other words, when the TX 100 and RX 200 recognize that they are operating in the fast charge mode, the TX 100 and RX 200 perform the calibration process for the power loss method described above in this state. Alternatively, the TX 100 and RX 200 set the threshold value using the threshold setting method for the waveform attenuation index described above. Alternatively, the TX 100 and RX 200 set the threshold value using the threshold setting method described above in measuring the coupling state index. Alternatively, the TX 100 and RX 200 set the temperature threshold value in the temperature-based foreign object detection method described above. When the TX 100 and RX 200 recognize that they are operating according to the BPP or EPP, the TX 100 and RX 200 perform the calibration process for the power loss method described above in this state. Alternatively, the TX 100 and RX 200 set the threshold value using the threshold setting method for the waveform attenuation index described above. Alternatively, the TX 100 and RX 200 may set a threshold value using the threshold setting method described above in measuring the coupling state index. Alternatively, the TX 100 and RX 200 may set a threshold value for temperature in the temperature-based foreign object detection method described above. When the TX 100 and RX 200 perform the calibration process for the power loss method described above, the TX 100 and RX 200 may perform foreign object detection processes based on one or more methods (temperature-based foreign object detection process, foreign object detection process using a waveform attenuation method, and foreign object detection process based on a coupling state) at the same timing. When the TX 100 and RX 200 set a threshold value for the waveform attenuation index described above, the TX 100 and RX 200 may p...

Claims

1. A powered device, comprising: a power receiving unit configured to wirelessly receive power from the power transmitting device; as well as A transmission unit is configured to transmit an identification data packet and an extended identification data packet to the power transmitting device, the identification data packet including information for identifying the power receiving device, and the extended identification data packet including information for indicating a power scheme.

2. The powered device according to claim 1, wherein: The transmission unit is configured to transmit the identification data packet and the extended identification data packet during a configuration phase.

3. The powered device according to claim 1, wherein The information indicating the power plan includes information related to a magnetic power plan (MPP).

4. The powered device according to claim 3, wherein: The magneto-power scheme, MPP, has a function of accurately aligning a power transmitting coil of the power transmitting device and a power receiving coil of the power receiving device by using a magnet of the power transmitting device and a magnet of the power receiving device.

5. A communication method, performed by a power receiving device that wirelessly receives power from a power transmitting device, the communication method comprising: transmitting an identification data packet to the power transmitting device, the identification data packet including information for identifying the powered device; as well as An extended identification data packet is transmitted, the extended identification data packet including information indicating a power scheme. The communication method according to claim 5 , wherein: The identification data packet and the extended identification data packet are transmitted during a configuration phase.

7. The communication method according to claim 5, wherein: The information indicating the power plan includes information related to a magnetic power plan (MPP).

8. The communication method according to claim 7, wherein: The magneto-power scheme, MPP, has a function of accurately aligning a power transmitting coil of the power transmitting device and a power receiving coil of the power receiving device by using a magnet of the power transmitting device and a magnet of the power receiving device.

9. A program for causing a computer to execute the communication method according to claim 5.

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