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

Abstract

To provide a power transmitting device, power receiving device, control method, and program capable of appropriate communication timing control when a plurality of communication methods for wireless power transmission control can be used.SOLUTION: In a wireless power transmission system including a power transmitting device and a power receiving device, a power receiving device 102, when communicating with the power transmitting device using a first communication unit 306, transmits a next packet after the elapse of a time T_silent after transmission of a packet, and when communicating with the power transmitting device using a second communication unit 307, can transmit the next signal without the elapse of the time T_silent after transmission of the packet.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In recent years, technological development of wireless power transmission systems has been widespread. Patent Document 1 discloses a power transmitting device and a power receiving device that comply with the standard (hereinafter referred to as the "WPC standard") established by the standardization organization Wireless Power Consortium (WPC). The transmitted power transmitted wirelessly varies depending on the state of the power receiving device, the relative positions of the power transmitting device and the power receiving device, and other factors. In the WPC standard, a control error (hereinafter referred to as "CE") packet is transmitted from the power receiving device to the power transmitting device, and the power transmitting device adjusts the transmitted power based on the CE packet. By transmitting the CE packet at a predetermined timing, the power receiving device can control the transmitted power in almost real time.

[0003] On the other hand, Patent Document 2 discloses a communication method in which a power transmitting device or a power receiving device communicates using an antenna different from the antenna used for transmitting and receiving power via wireless power transmission, and using a frequency different from the frequency used for wireless power transmission. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-007116 [Patent Document 2] Japanese Patent Application Publication No. 2019-187070 Summary of the Invention [Problem to be solved by the invention]

[0005] The WPC standard specifies the timing of communication between a power transmitting device and a power receiving device via an antenna used for transmitting and receiving power via wireless power transmission to control wireless power transmission. However, when communication for controlling wireless power transmission is performed via an antenna other than the antenna used for transmitting and receiving power via wireless power transmission, the communication timing specified in the WPC standard may not be appropriate. For example, unnecessary communication prohibition periods may be set for communication via an antenna other than the antenna used for transmitting and receiving power via wireless power transmission, resulting in longer periods between communications and potentially making it impossible to perform accurate control according to the situation.

[0006] The present disclosure provides a technique for controlling appropriate communication timing when multiple communication methods for controlling wireless power transmission are available. [Means for solving the problem]

[0007] A power receiving device according to one aspect of the present disclosure includes a power receiving means for wirelessly receiving power from a power transmitting device via a first antenna, a first communication means for communicating via the first antenna, a second communication means for communicating via a second antenna different from the first antenna, and a control means for controlling communication with the power transmitting device using either the first communication means or the second communication means, wherein the control means controls the first communication means, when communicating with the power transmitting device using the first communication means, to transmit a next signal after at least a specific period in which transmission is prohibited has elapsed after transmitting a signal, and controls the second communication means, when communicating with the power transmitting device using the second communication means, to transmit a next signal even if the specific period has not elapsed after transmitting a signal. When communicating with the power transmission device using the first communication means, the control means controls the first communication means so that, after transmitting a signal for controlling power, a next signal is transmitted after a waiting period that includes at least a specific period other than the specific period has elapsed, and when communicating with the power transmission device using the second communication means, the control means controls the second communication means so that, after transmitting a signal for controlling power, a next signal is transmitted after a waiting period that does not include the other specific period has elapsed, and the other specific period is the Power Control Hold-off time specified in the WPC standard. [Effects of the Invention]

[0008] According to the present disclosure, when a plurality of communication methods for controlling wireless power transmission are available, appropriate communication timing control can be performed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a wireless power transmission system. [Figure 2] FIG. 2 is a diagram illustrating a configuration of a power transmitting device. [Figure 3] FIG. 2 is a diagram illustrating a configuration of a power receiving device. [Figure 4] 4 is a flowchart of a process performed by a power transmitting device according to the first embodiment. [Figure 5] 4 is a flowchart of a process performed by a power receiving device according to the first embodiment. [Figure 6] 10 is a flowchart of a process for determining timing constraints in a power receiving device. [Figure 7] 10 is a flowchart of a process for determining timing constraints in a power receiving device. [Figure 8] FIG. 1 is a diagram illustrating the relationship between a BLE packet and a Qi packet. [Figure 9] FIG. 1 illustrates the operation of the system. [Figure 10] 1A is a diagram showing a communication sequence in the I&C phase, FIG. 1B is a diagram showing a communication sequence in the Negotiation phase, and FIG. 1C is a diagram showing a communication sequence in the Power Transfer phase. [Figure 11] FIG. 10 is a diagram illustrating communication timing constraints. [Figure 12] 10 is a flowchart of a process performed by a power transmitting device according to a second embodiment. [Figure 13] 10 is a flowchart of a process performed by a power receiving device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiments are merely examples for explaining the technical ideas of the present disclosure, and are not intended to limit the present disclosure to the configurations and methods described in the embodiments. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the present disclosure, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components.

[0011] (System configuration) FIG. 1 shows an example of the configuration of a wireless power transmission system according to this embodiment. In one example, this system includes a power transmitting device 101 and a power receiving device 102. Hereinafter, the power transmitting device 101 may be referred to as TX, and the power receiving device 102 may be referred to as RX. The TX 101 is an electronic device that wirelessly transmits power to the RX 102 placed on a charging stand 103. The RX 102 is an electronic device that receives power from the TX 101 and charges its built-in battery. The TX 101 and the RX 102 may have a function of executing applications other than wireless power transmission. For example, the TX 101 and the RX 102 may be storage devices such as hard disk drives and memory devices, or information processing devices such as personal computers (PCs), smartphones, and tablet terminals. The TX 101 and the RX 102 may be image input devices such as imaging devices (cameras, video cameras, etc.) and scanners, image output devices such as printers, copiers, and projectors, robots, or vehicles. The RX 102 may also be an electric vehicle. The TX101 may be a charger installed in a console or the like inside a vehicle, or may be a charging device for charging an electric vehicle. The RX102 does not need to have a built-in battery.

[0012] It is assumed that the RX102 and the TX101 each have a communication function based on BLE (Bluetooth (registered trademark) Low Energy). Specifically, the RX102 and the TX101 communicate based on the Bluetooth 4.0 or later standard. The detailed configurations of the TX101 and the RX102 will be described later using Figures 2 and 3. Note that, hereinafter, the standard defined in Bluetooth 4.0 or later that specifies BLE will be referred to as the BLE standard. Note that the BLE is an intermittent communication method. Here, the intermittent communication method refers to a communication method in which a communication unit (a control IC for BLE communication) is intermittently driven (activated), communication is performed only while the communication unit is driven, and the power of the communication unit (a control IC for BLE communication) is turned off or put into a low power consumption state during other periods, repeating intermittent operation. This achieves a reduction in power consumption.

[0013] This system performs wireless power transmission using an electromagnetic induction method based on the WPC standard defined by the Wireless Power Consortium (WPC). That is, the TX101 and the RX102 perform wireless power transmission based on the WPC standard between the transmitting coil of the TX101 and the receiving coil of the RX102. Note that the wireless power transmission method is not limited to the method defined by the WPC standard, and may be other methods such as electromagnetic induction, magnetic field resonance, electric field resonance, microwave, or laser. In addition, although this embodiment uses wireless power transmission for contactless charging, wireless power transmission may also be performed for purposes other than contactless charging.

[0014] In the WPC standard, the amount of power that a power receiving device is guaranteed to be able to output to a load (e.g., a charging circuit, a battery, etc.) is specified by a value called Guaranteed Power (hereinafter referred to as "GP"). GP indicates a power value that is guaranteed to be output to a load (e.g., a charging circuit, a battery, etc.) of the power receiving device, even if, for example, the positional relationship between the power receiving device and the power transmitting device fluctuates and the power transmission efficiency between the power receiving antenna 205 and the power transmitting antenna 105 decreases. For example, if the GP is 5 watts, the power transmitting device controls power transmission so as to output 5 watts to the load in the power receiving device, even if the positional relationship between the power receiving antenna and the power transmitting antenna fluctuates and the power transmission efficiency decreases. GP is determined by negotiation between the power transmitting device and the power receiving device. This embodiment is applicable not only to GP but also to a configuration in which power is transmitted and received at a power determined by mutual negotiation between the power transmitting device and the power receiving device.

[0015] The TX101 and RX102 according to this embodiment communicate for power transmission control based on the WPC standard. The WPC standard defines multiple phases, including a power transfer phase in which power transmission is performed and a phase before actual power transmission, and communication for necessary power transmission control is performed in each phase. Phases before power transmission include a selection phase, a ping phase, an identification and configuration phase, a negotiation phase, and a calibration phase. Note that the identification and configuration phase will be referred to as the I&C phase below.

[0016] In the Selection phase, the power transmitting device intermittently transmits Analog Pings to detect that an object has been placed on the power transmitting device (for example, that a power receiving device, a conductor piece, or the like has been placed on a charging stand). The power transmitting device detects at least one of the voltage value and current value of the power transmitting antenna 105 when the Analog Ping is transmitted, and determines that an object is present if the voltage value is below a certain threshold or if the current value exceeds a certain threshold, and transitions to the Ping phase.

[0017] In the Ping phase, the power transmitting device transmits a Digital Ping, which has a higher power than the Analog Ping. The power of the Digital Ping is sufficient to activate the control unit of the power receiving device placed on the power transmitting device. In other words, the Digital Ping is the power transmitted from the power transmitting device to activate the power receiving device. The power receiving device notifies the power transmitting device of the magnitude of the received voltage. This notification is performed using a Signal Strength Packet defined in the WPC standard. In this manner, the power transmitting device recognizes that the object detected in the Selection phase is the power receiving device by receiving a response from the power receiving device that received the Digital Ping. Upon receiving the notification of the received voltage value, the power transmitting device transitions to the I&C phase. Furthermore, before transmitting the Digital Ping, the power transmitting device measures the Q-factor of the power transmitting antenna 105. This measurement result is used when performing foreign object detection processing using a Q-factor measurement method. In this disclosure, a foreign object is, for example, a paper clip or an IC card. Among objects that are an integral part of a power receiving device and a product incorporating the power receiving device or a product incorporating a power transmitting device and a power receiving device, objects that may unintentionally generate heat when exposed to wireless power transmitted by a power transmitting antenna are not considered foreign objects.

[0018] In the I&C phase, the power transmitting device identifies the power receiving device and obtains device configuration information (capability information) from the power receiving device. The power receiving device transmits an ID packet and a configuration packet. The ID packet contains identifier information for the power receiving device, and the configuration packet contains device configuration information (capability information) for the power receiving device. Upon receiving the ID packet and configuration packet, the power transmitting device responds with an acknowledgement (ACK, positive response). Then, the I&C phase ends.

[0019] In the negotiation phase, the GP value is determined based on the GP value requested by the power receiving device and the power transmission capability of the power transmitting device. The power transmitting device then performs a foreign object detection process using the Q-factor measurement method in response to a request from the power receiving device. The WPC standard also specifies a method in which, after transitioning to the power transfer phase, the same process as the negotiation phase is performed again at the request of the power receiving device. The phase in which these processes are performed after the power transfer phase is called the renegotiation phase.

[0020] In the calibration phase, calibration is performed based on the WPC standard. The power receiving device notifies the power transmitting device of a predetermined received power value (received power value under light load / received power value under maximum load), and the power transmitting device makes adjustments to transmit power efficiently. The received power value notified to the power transmitting device can be used for foreign object detection processing using the Power Loss method.

[0021] In the power transfer phase, control is performed to start and continue power transmission, and to stop power transmission due to an error or full charge. In the power transfer phase, control is performed to notify the charge state, stop power transmission due to a full charge, and the like while performing real-time control of the transmitted power. Here, real-time control refers to control with high immediacy. In the power transfer phase, the transmitted power is controlled immediately in response to a request from the power receiving device. This allows the power receiving device to appropriately control the output to a battery, for example. Note that real-time control does not have to be control at exactly the same timing. In other words, the transmitted power may be controlled simultaneously with a request from the power receiving device, or the transmitted power may be controlled within a certain short period of time in response to a request from the power receiving device.

[0022] In this embodiment, the TX101 and the RX102 perform a series of communications for power transmission control by switching between in-band communication and out-of-band communication. In-band communication is communication in which a signal is superimposed on electromagnetic waves corresponding to power using an antenna (coil) used for transmitting and receiving power. The range in which in-band communication based on the WPC standard is possible between the TX101 and the RX102 is approximately the same as the power transmission range (active area). Out-band communication is communication using a frequency different from the frequency used for transmitting and receiving power via an antenna different from the antenna used for transmitting and receiving power. The communication method used in out-band communication is BLE communication. The TX101 operates as a BLE Central device, and the RX102 operates as a BLE Peripheral device. Note that the BLE roles may be reversed. The communication method used in out-band communication may be one of the following methods. That is, it may be Wi-Fi (registered trademark), ZigBee (registered trademark), NFC (Near Field Communication), or other communication methods standardized in the IEEE 802.11 series.

[0023] (Device configuration) Next, the configurations of the power transmitting device 101 (TX) and the power receiving device 102 (RX) according to this embodiment will be described. Note that the configurations described below are merely examples, and part (or in some cases the entire) of the described configurations may be replaced with other configurations that perform similar functions or may be omitted, or additional configurations may be added to the described configurations. Furthermore, one block shown in the following description may be divided into multiple blocks, or multiple blocks may be integrated into one block.

[0024] 2 is a diagram showing an example of the configuration of the TX 101 according to this embodiment. In one example, the TX 101 includes a control unit 201, a power supply unit 202, a power transmission unit 203, a detection unit 204, a power transmission coil 205, a first communication unit 206, a second communication unit 207, a display unit 208, an operation unit 209, a memory 210, and a timer 211.

[0025] The control unit 201 controls the entire TX 101 by executing a control program stored in the memory 210, for example. In one example, the control unit 201 performs control necessary for device authentication and power transmission in the TX 101. The control unit 201 may also perform control for executing applications other than wireless power transmission. The control unit 201 is configured to include one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 201 may be configured with hardware such as an Application Specific Integrated Circuit (ASIC). The control unit 201 may also be configured to include an array circuit such as an FPGA (Field Programmable Gate Array) compiled to execute predetermined processes. The control unit 201 stores information to be stored while various processes are being executed in the memory 210. The control unit 201 may also measure time using a timer 211.

[0026] Power supply unit 202 is a power source that supplies power when at least control unit 201 and power transmission unit 203 operate. Power supply unit 202 can be, for example, a wired power receiving circuit that receives power from a commercial power source, a battery, etc. The battery stores the power supplied from the commercial power source.

[0027] The power transmitting unit 203 converts DC or AC power input from the power supply unit 202 into AC frequency power in a frequency band used for wireless power transmission, and inputs the AC frequency power to the power transmitting coil 205 to generate electromagnetic waves for receiving power at the RX102. The frequency of the AC power generated by the power transmitting unit 203 is about several hundred kHz (for example, 110 kHz to 205 kHz), which is different from the BLE communication frequency (2.4 GHz) used in out-band communication. Based on an instruction from the control unit 201, the power transmitting unit 203 inputs the AC frequency power to the power transmitting coil 205 so that the power transmitting coil 205 outputs electromagnetic waves for transmitting power to the RX102. The power transmitting unit 203 also controls the intensity of the electromagnetic waves to be output by adjusting the voltage (power transmitting voltage) or current (power transmitting current) input to the power transmitting coil 205. Increasing the transmission voltage or current increases the intensity of the electromagnetic waves, and decreasing the transmission voltage or current decreases the intensity of the electromagnetic waves. Furthermore, based on instructions from the control unit 201, the power transmitting unit 203 controls the output of AC frequency power so that power transmission from the power transmitting coil 205 starts or stops.

[0028] The detection unit 204 detects whether an object is placed in the power transmission range 104 based on the WPC standard. The detection unit 204 detects, for example, the voltage value or current value of the power transmitting coil 205 when the power transmitting unit 203 transmits an Analog Ping of the WPC standard via the power transmitting coil 205. Then, the detection unit 204 can determine that an object is present in the range 104 when the voltage is below a predetermined voltage value or the current value exceeds a predetermined current value. Whether the object is the RX102 or another foreign object is determined when a predetermined response is received in response to a Digital Ping transmitted by the first communication unit 206 via in-band communication.

[0029] The first communication unit 206 performs communication with the RX102 in accordance with each phase of the WPC standard as described above through in-band communication. The first communication unit 206 modulates the electromagnetic waves output from the power transmitting coil 205 and transmits information to the RX102. The first communication unit 206 also demodulates the electromagnetic waves output from the power transmitting coil 205 and modulated by the RX102 to acquire information transmitted by the RX102. That is, communication performed by the first communication unit 206 is performed by superimposing a signal on the electromagnetic waves corresponding to the transmitted power from the power transmitting coil 205.

[0030] The second communication unit 207 performs communication in each phase of the WPC standard as described above through out-band communication with the RX 102. The second communication unit 207 has, for example, a modulation / demodulation circuit and a communication protocol processing function required for performing BLE communication.

[0031] The display unit 208 presents information to the user by any method such as visually, audibly, or tactilely. The display unit 208 notifies the user of, for example, information indicating the state of the TX101 or the state of the wireless power transmission system including the TX101 and the RX102 as shown in Fig. 1. The display unit 208 is configured to include, for example, a liquid crystal display, an LED display, an organic EL display, a speaker, a vibration generating circuit, or other notification devices.

[0032] The operation unit 209 has a reception function for receiving operations on the TX 101 from the user. The operation unit 209 is configured to include, for example, a voice input device such as a button, keyboard, or microphone, a motion detection device such as an acceleration sensor or gyro sensor, or other input device. A device in which the display unit 208 and the operation unit 209 are integrated, such as a touch panel, may be used. The memory 210 stores various information as described above. The memory 210 may store information obtained by a functional unit different from the control unit 201. The timer 211 measures time using, for example, a count-up timer that measures the elapsed time from the time of activation, or a count-down timer that counts down from a set time.

[0033] 3 is a diagram showing an example of the configuration of the RX 102 according to this embodiment. In one example, the RX 102 includes a control unit 301, a battery 302, a power receiving unit 303, a detection unit 304, a power receiving coil 305, a first communication unit 306, a second communication unit 307, a display unit 308, an operation unit 309, a memory 310, a timer 311, and a charging unit 312.

[0034] The control unit 301 controls the entire RX102 by executing a control program stored in the memory 310, for example. In one example, the control unit 301 performs control necessary for device authentication and power reception in the RX102. The control unit 301 may also perform control for executing applications other than wireless power transmission. The control unit 301 is configured to include one or more processors, such as a CPU or an MPU. Note that the control unit 301 may also be configured to include hardware dedicated to specific processing, such as an ASIC, or an array circuit, such as an FPGA, compiled to execute predetermined processing. The control unit 301 stores information to be stored while various processes are being executed in the memory 310. The control unit 301 may also measure time using a timer 311.

[0035] The power receiving unit 303 acquires AC power generated by electromagnetic induction in the power receiving coil 305. Specifically, an induced electromotive force is generated in the power receiving coil 305 by electromagnetic waves radiated from the power transmitting coil 205 of the TX101, and the power receiving unit 303 acquires the power generated in the power receiving coil 305. The power receiving unit 303 then converts the AC power into DC or AC power of a predetermined frequency, and outputs the power to a charging unit 312 that performs processing to charge the battery 302. In other words, the power receiving unit 303 supplies power to a load in the RX102. The above-mentioned GP is power that is guaranteed to be output from the power receiving unit 303. The battery 302 stores the power received via the power receiving coil 305.

[0036] The detection unit 304 detects whether the RX102 is placed within the range 104 in which it can receive power from the TX101, based on the WPC standard. The detection unit 304 detects, for example, the voltage value or current value of the power receiving coil 305 when the power receiving unit 303 receives a Digital Ping signal conforming to the WPC standard via the power receiving coil 305. The detection unit 304 can determine that the RX102 is placed within the range 104, for example, when the voltage is below a predetermined voltage threshold or when the current value exceeds a predetermined current threshold.

[0037] The first communication unit 306 communicates with the TX101 through in-band communication in accordance with each phase of the WPC standard as described above. The first communication unit 306 demodulates the electromagnetic waves input from the power receiving coil 305 to acquire information transmitted from the TX101, and performs load modulation on the electromagnetic waves to superimpose information to be transmitted to the TX101 onto the electromagnetic waves, thereby communicating with the TX101. That is, communication by the first communication unit 306 is performed by superimposing a signal on an electromagnetic wave corresponding to the transmitted power from the power transmitting coil 205 of the TX101.

[0038] The second communication unit 307 performs communication in each phase of the WPC standard as described above through out-band communication with the TX 101. The second communication unit 307 has, for example, a modulation / demodulation circuit and a communication protocol processing function required for performing BLE communication.

[0039] The display unit 308 presents information to the user by any method such as visually, audibly, or tactilely. The display unit 308 notifies the user of, for example, the status of RX102 or the status of the wireless power transmission system including TX101 and RX102 as shown in Fig. 1. The display unit 308 is configured to include, for example, a liquid crystal display, an LED display, an organic EL display, a speaker, a vibration generating circuit, or other notification devices.

[0040] The operation unit 309 has a reception function for receiving operations on the RX102 from the user. The operation unit 309 is configured to include, for example, a voice input device such as a button, keyboard, or microphone, a motion detection device such as an acceleration sensor or gyro sensor, or other input device. A device in which the display unit 308 and the operation unit 309 are integrated, such as a touch panel, may be used. The memory 310 stores various information as described above. The memory 310 may also store information obtained by a functional unit different from the control unit 301. The timer 311 measures time, for example, using a count-up timer that measures the elapsed time from the time of activation, or a count-down timer that counts down from a set time.

[0041] (Processing flow) Next, an example of the flow of power transmission and reception control processing executed by the TX 101 and the RX 102 will be described.

[0042] FIG. 4 is a flowchart showing an example of the flow of power transmission control processing executed by the TX 101. This processing can be implemented, for example, by the control unit 201 of the TX 101 executing a program read from the memory 210. At least a part of the following procedure can be implemented by hardware. In this case, the hardware can be implemented, for example, by using a predetermined compiler to automatically generate a dedicated circuit using a gate array circuit such as an FPGA from a program for implementing each processing step. This processing can also be executed when the TX 101 is powered on, when the user of the TX 101 inputs an instruction to start a wireless power transmission application, or when the TX 101 is connected to a commercial power source and receives power. This processing can also be started by some other trigger.

[0043] First, the TX101 executes the processes defined as the Selection phase and Ping phase of the WPC standard, and waits for the RX102 to be placed on it (S401). The TX101 repeatedly and intermittently transmits Analog Pings of the WPC standard to detect an object that exists within the power transmission range 104. Then, when the TX101 detects that an object exists within the power transmission range, it transmits a Digital Ping. Then, when the TX101 receives a predetermined response to the Digital Ping, it determines that the detected object is the RX102 and that the RX102 has been placed on the charging stand 103.

[0044] When the TX101 detects that the RX102 has been placed, it acquires identification information from the RX102 through in-band communication in the I&C phase defined by the WPC standard (S402). Figure 10(A) shows the flow of communication in the I&C phase. In the I&C phase, the RX102 transmits an Identification Packet (ID Packet) to the TX101 (F1001). The ID Packet contains the Manufacturer Code and Basic Device ID, which are identification information for each individual RX102, as well as information elements that can identify the version of the WPC standard that is supported. The RX102 further transmits a Configuration Packet to the TX101 (F1002). The Configuration Packet contains the Maximum Power Value, which is a value that specifies the maximum power that the RX102 can supply to a load, and information indicating whether the RX102 has the negotiation function of the WPC standard. Upon receiving these packets, the TX101 transmits an ACK (F1003), and the I&C phase ends. Note that the TX101 may acquire the identification information of the RX102 by a method other than the communication in the I&C phase of the WPC standard. The identification information for each individual RX102 may be a Wireless Power ID. Furthermore, the identification information for each individual RX102 may be any other identification information capable of identifying the individual RX102, such as a Bluetooth address (hereinafter referred to as "BD_ADDR") unique to the second communication unit 307 of the RX102. Note that the BD_ADDR is an 8-byte address used in BLE. The BD_ADDR is a public address defined in the BLE standard that indicates, for example, the manufacturer of the RX102 or individual identification information of the BLE communication function (second communication unit 204). Note that the BD_ADDR may be a random address.

[0045] Next, the TX101 determines whether outband communication with the RX102 via BLE is possible (S403). Specifically, the TX101 waits for an advertising packet including the identification information of the RX102 via BLE (using the second communication unit 207). For example, the TX101 performs a BLE scan operation and waits for an advertising packet including the identification information of the RX102 and information indicating that the identification information of the RX102 is included. For example, the TX101 indicates that the advertising packet includes the identification information of the RX102 by setting the AD Type of the advertising packet of the BLE standard to a predetermined value. Then, it is defined in advance that when the AD Type is the predetermined value, the identification information of the RX102 is included in the AD Data. Then, this definition is shared between the TX101 and the RX102, so that the advertising packet including the above-mentioned information can be waited for. Here, the identification information of the RX102 is information for identifying each individual RX102. The identification information of the RX102 is, for example, a Manufacturer Code and a Basic Device ID defined in the WPC standard. The identification information of the RX102 may also be a Wireless Power ID or a BD_ADDR unique to the second communication unit 307 of the RX102. When the BD_ADDR is used as the identification information of the RX102, the identification information is included in the header of the advertising packet, not in the AD Data. If the TX101 receives an advertising packet including the identification information of the RX102 within a predetermined time, the TX101 determines that outband communication via BLE with the RX102 is possible. If not, the TX101 determines that outband communication via BLE with the RX102 is not possible. Whether outband communication via BLE with the RX102 is possible may also be determined by other methods. For example, information such as whether the RX102 supports outband communication and whether communication is possible may be stored in the configuration packet. In this case, the TX101 determines whether outband communication via BLE with the RX102 is possible based on the corresponding information element in the configuration packet.As a result, when out-band communication via BLE with the RX102 is not possible, the time spent waiting for advertising packets can be omitted, enabling the start of power transmission to the power receiving device to be accelerated.

[0046] If TX101 determines that outband communication is possible (YES in S403), it establishes a BLE connection with RX102, the sender of the advertising packet (S404). TX101 establishes a BLE connection with RX102 by sending CONNECT_REQ, a connection request in the BLE standard, to the BD_ADDR included in the header of the advertising packet from RX102. Next, TX101 sets the Connection Interval, which is the interval for BLE intermittent communication, based on the request from RX102 (S405). This is done by receiving LL_CONNECTION_PARAM_REQ in the BLE standard from RX102 and returning LL_CONNECTION_UPDATE_IND. TX101 then performs subsequent communication with RX102 using BLE outband communication. If the TX 101 determines that out-band communication with the RX 102 is not possible (NO in S403), it skips the processes of S404 and S405, and performs subsequent communication with the RX 102 by in-band communication.

[0047] Next, TX101 determines the GP through negotiation with RX102 based on the result of the equipment authentication, the request from RX102, and the power transmission capacity of its own device (S406). In S406, communication in the negotiation phase of the WPC standard is performed, as shown in FIG. 10(B). First, RX102 notifies TX101 of the requested GP value by sending a Specific Request to TX101 (F1011). TX101 determines whether to accept the request based on the power transmission capacity of its own device and other conditions, and sends ACK if accepted or NACK if not accepted to RX102 (F1012). If TX101 accepts the request from RX102, the determined GP value will be the value requested by RX102; otherwise, it will be a predetermined value (e.g., 5 watts) defined in the WPC standard.

[0048] Next, the TX101 performs the calibration phase process of the WPC standard (S407). The calibration phase process is a preliminary measurement to accurately detect foreign matter between the TX101 and the RX102, but as it is the same as the conventional technology, a detailed description of it will be omitted here.

[0049] After that, the TX101 transmits power until the RX102 is fully charged (S408). In S408, communication in the Power Transfer phase of the WPC standard is performed, as shown in FIG. 10(C). The RX102 repeatedly transmits a Control Error packet (hereinafter referred to as a "CE packet") (F1021) to the TX101 at time intervals of t_interval. The t_interval is a value defined in the WPC standard, and is, for example, 250 milliseconds. The CE packet includes a request for how much to increase or decrease the transmission power. The TX101 adjusts the transmission power by controlling the current of the power transmitting antenna 205 based on the received CE packet. In other words, the CE packet is a parameter for adjusting the transmission power. By repeating this process, power is transmitted at an appropriate power level according to the request of the RX102, almost in real time.

[0050] When the RX102 is fully charged, it transmits an End Power Transfer packet (hereinafter referred to as an "EPT packet") (F1022) to end the Power Transfer phase. The RX102 may transmit an EPT packet for reasons other than full charge. Furthermore, when the Power Transfer phase ends, the TX101 stops transmitting power to the RX102 for charging.

[0051] Furthermore, if the TX 101 does not receive the next CE packet even though t_timeout has elapsed since the last CE packet it received, it determines that the RX 102 has been removed from the charging stand 103 and ends the Power Transfer phase. t_timeout is a value defined in the WPC standard, and is, for example, 1500 milliseconds.

[0052] Note that the RX102 may transmit a packet (F1023) other than a CE packet during the power transfer phase. An example of a packet other than a CE packet is a Charge Status packet that notifies the TX101 of the status of the battery 302 of the RX102. The Charge Status packet stores a Charge Status Value that indicates the percentage of charge of the battery 302. When the TX101 receives the Charge Status packet, it may notify the user of the charge status by, for example, displaying text or graphics based on the Charge Status Value on the display unit 208. The TX101 may receive the Charge Status packet at any time, and may notify the user at any time.

[0053] Here, the processing of real-time control of transmission power performed between TX 101 and RX 102 will be explained using FIG. 11(c). After receiving a CE packet 1103, TX 101 adjusts the transmission power based on the Control Error Value included in the CE packet 1103, taking the time t_control after t_delay has elapsed. t_delay and t_control are values ​​determined within the ranges defined by the WPC standard, for example, 5 milliseconds and 25 milliseconds. Here, after transmitting the CE packet 1103, RX 102 must not transmit a Qi packet 1104 (here, the next CE packet) until TX 101 has completed adjusting the transmission power based on the CE packet 1103. In other words, RX 102 can transmit the next CE packet (Qi packet 1104) only after at least the total time of t_delay and t_control has elapsed after transmitting the CE packet 1103. In the power transfer phase, the TX101 and RX102 perform real-time control of the transmission power under the timing constraints represented by t_interval, t_timeout, t_delay, and t_control described above. Information on these timing constraints may be stored in advance in the memory 210 and memory 310 of the TX101 and RX102, respectively, or may be stored by the RX102 and notified to the TX101 in the I&C phase. The TX101 may also store the information and notify the RX102, or may notify the information outside the I&C phase.

[0054] As mentioned above, the CE packet is a packet for real-time control (hereinafter referred to as a "real-time control packet"). In contrast, notifications to users via Charge Status packets have no restrictions on the timing of transmission, reception, or processing. In other words, Charge Status packets are not real-time control packets. There may be other packets that are not for real-time control.

[0055] Returning to Figure 4, after the Power Transfer phase ends, if TX101 was connected to RX102 via BLE in S403, it will disconnect the connection and end the process (YES in S409, S410). Note that TX101 may continue communication with RX102 after S410, but in that case, it will use in-band communication.

[0056] Next, an example of the flow of power reception control processing executed by the RX102 will be described with reference to Figure 5. This processing can be implemented, for example, by the control unit 301 of the RX102 executing a program read from the memory 310. Note that at least part of the following procedure may be implemented by hardware. In this case, the hardware can be implemented, for example, by using a predetermined compiler to automatically generate a dedicated circuit using a gate array circuit such as an FPGA from a program for implementing each processing step.

[0057] After starting the power receiving control process, the RX102 executes the processes defined as the Selection phase and Ping phase of the WPC standard, and waits for its own device to be placed on the TX101 (S501). The RX102 detects that it has been placed on the TX101, for example, by detecting a Digital Ping from the TX101.

[0058] When the RX102 detects that its own device has been placed on the TX101, it transmits information including its own device's identification information to the TX101 by in-band communication using the ID packet and configuration packet described with reference to Fig. 10(A) (S502). Note that the RX102's identification information may be transmitted by a method other than communication in the I&C phase of the WPC standard, and other identification information such as BD_ADDR may be used as long as it is information that can identify each individual RX102. Furthermore, the RX102 may transmit information other than the identification information to the TX101 in S502.

[0059] Next, RX102 determines whether outband communication via BLE with TX101 is possible (S503). Specifically, RX102 repeatedly transmits an advertising packet including its own device identification information via BLE (using the second communication unit 307) and waits for a BLE CONNECT_REQ from TX101. RX102 can indicate that the advertising packet includes its identification information by, for example, setting the AD Type of the BLE advertising packet to a predetermined value. The identification information of RX102 is, for example, a Manufacturer Code and a Basic Device ID defined in the WPC standard. Alternatively, the identification information of RX102 may be a Wireless Power ID or a BD_ADDR unique to the second communication unit 307 of RX102. If RX102 can receive a CONNECT_REQ from TX101 within a predetermined time, it determines that outband communication via BLE with TX101 is possible. Otherwise, it determines that outband communication via BLE with TX101 is not possible. Note that whether outband communication via BLE with the TX101 is possible may be determined by a method other than the above. For example, the RX102 may receive, from the TX101, information or a signal indicating whether the TX101 supports BLE, or information or a signal indicating whether the TX101 is capable of communication via BLE. In this case, the RX102 may determine whether outband communication via BLE with the TX101 is possible based on the received information or signal. As a result, if outband communication via BLE with the TX101 is not possible, the time spent waiting for reception of CONNECT_REQ can be shortened, and power transmission can be started earlier.

[0060] If RX102 determines that outband communication is possible (YES in S503), it establishes a BLE connection with TX101, which is the sender of the CONNECT_REQ (S504). RX102 establishes a BLE connection by receiving CONNECT_REQ. Next, RX102 requests TX101 to set the Connection Interval, which is the interval for BLE intermittent communication, to the same time as the scheduled transmission interval of real-time control packets (hereinafter referred to as "Qi packets" to explicitly distinguish them from BLE packets) (S505). An example of a Qi packet for real-time control is a CE packet, and its scheduled transmission interval is t_interval. RX102 requests setting of the Connection Interval by, for example, transmitting LL_CONNECTION_PARAM_REQ in the BLE standard. Note that RX102 may request TX101 to set the Connection Interval to an integer division of t_interval, instead of setting it to the same as t_interval. For example, if t_interval=250 milliseconds, the Connection Interval may be set to half that, or 125 milliseconds.

[0061] RX102 will then communicate with TX101 by out-band communication using BLE. If RX102 determines that out-band communication is not possible (NO in S503), it skips the processes of S504 and S505, and will then communicate with RX102 by in-band communication.

[0062] RX102 then transmits the requested GP value to TX101 and waits for a response from TX101 before deciding on the GP (S506). In S506, communication in the negotiation phase of the WPC standard is carried out as described in FIG. 10(B).

[0063] Next, the RX102 performs the calibration phase process of the WPC standard (S507). The calibration phase process is a preliminary measurement to accurately detect foreign matter between the TX101 and the RX102, but as it is the same as the conventional technology, a detailed description thereof will be omitted here.

[0064] Thereafter, the RX 102 receives power until the battery 302 is fully charged (S508). In S508, as explained in Fig. 10(C), the RX 102 repeatedly transmits a CE packet at intervals of t_interval, and finally transmits an EPT packet to end the process.

[0065] Returning to Figure 5, after the Power Transfer phase ends, if the BLE connection with RX102 was established in S503, RX102 disconnects the connection and ends the process (YES in S509, S510). Note that RX102 may continue communication with TX101 after S510, but in that case, communication is performed via in-band communication.

[0066] As described above, when out-band communication using BLE is possible between TX101 and RX102 (YES in S403 and S503), communication in the following phases is performed using BLE. That is, the Negotiation phase, the Calibration phase, and the Power Transfer phase. Note that even when out-band communication using BLE is possible, not all of the above communications need to be performed using BLE. For example, only the communication in the Power Transfer phase may be performed using BLE.

[0067] Here, a method for transmitting Qi packets defined in the WPC standard using communication signals used in BLE communication (hereinafter referred to as "BLE packets") will be described. In this embodiment, after BLE connection is established, the TX101 operates as a GATT (Generic Attribute Profile) Client of the BLE standard. The second communication units 207 and 307 are configured so that the RX102 operates as a GATT Server of the BLE standard. At this time, the TX101 performs Write Characteristic Value processing of the BLE standard, and the RX102 performs Handle Value Notification processing (hereinafter referred to as "Notify processing"). This allows each to transmit an arbitrary byte sequence of up to 20 bytes as an Attribute Value of the BLE standard. Note that the maximum upper limit of 20 bytes can be further extended by performing Exchange MTU processing of the BLE standard. Note that the TX101 may be a GATT Server and the RX102 may be a GATT Client, or an arbitrary byte sequence may be transmitted using a BLE profile other than GATT. In other words, multiple Qi packets are stored in the Attribute Value of a BLE communication packet.

[0068] Because the size of a Qi packet in the WPC standard is small compared to the upper limit of the attribute value of a BLE packet, in this embodiment, one or more Qi packets are stored together in one BLE packet and transmitted. FIG. 8 shows an example in which three Qi packets are stored in one BLE packet. The same applies to numbers other than three. First, the structure of a Qi packet will be described. A Qi packet 800 is composed of a header 801 and a message 802. The header 801 is a one-byte value that indicates the type of Qi packet, such as a CE packet or an EPT packet. For example, for a CE packet, the value of the header 801 is 03 in hexadecimal. The message 802 is a byte sequence defined for each type of Qi packet, and the number of bytes varies depending on the type of Qi packet. For example, if the packet type is a CE packet, the message 802 is a one-byte control error value. Note that a Qi packet in the WPC standard also includes a preamble and a checksum, but these are not necessary when transmitting via BLE, so their description will be omitted. Reference numeral 820 in FIG. 8 represents a byte string stored in the Attribute Value 811 of the BLE packet 810. A field 821 at the beginning of the byte string 820 stores the number of Qi packets included in this Attribute Value. In this example, it is 3. The following field 822 stores the number of bytes of the first Qi packet, and field 823 stores the contents of the first Qi packet, i.e., the Header 801 and the Message 802. Similarly, fields 824 and 825 store information about the second Qi packet, and fields 826 and 827 store information about the third Qi packet. In this way, multiple Qi packets are stored in one BLE packet. Note that the storage format described above is an example, and other storage formats may be used.

[0069] Next, the transmission process of the power receiving device will be described with reference to Fig. 6. If RX102 does not use BLE communication (or is not using BLE communication) (NO in S601), it imposes restrictions specific to in-band communication when communicating (S602). In other words, in Fig. 5, if BLE communication with TX101 is not possible (NO in S503), it imposes restrictions specific to in-band communication. Also, if RX102 uses BLE communication (or is using BLE communication) (YES in S601), it does not impose restrictions specific to in-band communication when transmitting BLE packets (S603). In other words, in Fig. 5, if BLE communication with TX101 is possible (YES in S503), it does not impose restrictions specific to in-band communication when transmitting BLE packets.

[0070] Here, the constraints specific to in-band communication will be explained using FIG. 11(a). FIG. 11(a) shows the transmission timing of Qi packets defined in the WPC standard. Reference numerals 1101 and 1102 are Qi packets transmitted by the RX102 via in-band communication. Time t_silent indicates the time required for the fluctuations in the current flowing through the power transmitting coil 205 of the TX101 or the applied voltage due to modulation to stabilize after transmitting packet 1101 via in-band communication. When transmitting the Qi packet 1102, the RX102 starts transmitting the preamble of the Qi packet 1102 at time t_silent from the end of the previous Qi packet 1101. Alternatively, when transmitting the Qi packet 1102, the RX102 starts transmitting the preamble of the Qi packet 1102 later than time t_silent and earlier than time t_start1 from the end of the previous Qi packet 1101. That is, RX102 does not start transmitting any Qi packet preambles during time t_silent. In other words, time t_silent is a period during which signal transmission is prohibited. A constraint specific to in-band communication is the timing of Qi packet transmission related to time t_silent. By setting this constraint, RX102 can start transmitting the preamble of the Qi packet 1102 after the current or voltage of the transmitting coil 205 has stabilized, thereby enabling stable in-band communication. In addition, RX102 may set a constraint that it starts transmitting the preamble of the next Qi packet at time t_start1 from the end of the previous Qi packet (or before time t_start1).

[0071] FIG. 11(b) shows the timing when RX102 transmits a packet in BLE communication. According to FIG. 11(b), the time t_silent does not exist. The length of the time t_start2 may be the same as the time t_start1. RX102 starts transmitting the preamble of a BLE packet 1112 containing another Qi packet from the end of a BLE packet 1111 containing the immediately preceding Qi packet. Alternatively, when transmitting the BLE packet 1112, RX102 starts transmitting the preamble of the BLE packet 1112 containing the Qi packet before the time t_start2 has elapsed from the end of the immediately preceding BLE packet 1111. The reason why the time t_silent does not exist in FIG. 11(b) is that the time t_silent is provided to stabilize fluctuations in the current flowing through or the applied voltage of the transmitting coil 205 due to in-band communication. In other words, when using BLE communication, fluctuations in the current or voltage of the transmitting coil 205 due to in-band communication do not occur. When performing BLE communication, high-speed control can be achieved by eliminating the constraints specific to in-band communication. In other words, high-speed communication is possible because a BLE packet 1112 including a Qi packet can be transmitted within the time period t_silent shown in Figure 11(a). For example, the transmission interval of Qi packets for real-time control can be shortened, allowing the RX102 to control power transmission more precisely.

[0072] Next, the power level control process of the TX101 will be described with reference to Figure 7. If the TX101 does not use BLE communication (or is not using BLE communication) (YES in S701), it imposes restrictions specific to in-band communication when performing power level control (S702). In other words, in Figure 4, if BLE communication with the RX102 is not possible (NO in S403), it imposes restrictions specific to in-band communication. Also, if the TX101 uses BLE communication (or is using BLE communication) (YES in S701), it does not impose restrictions specific to in-band communication when performing power level control (S703). In other words, in Figure 4, if BLE communication with the RX102 is possible (YES in S403), it does not impose restrictions specific to in-band communication.

[0073] Here, the constraints specific to in-band communication will be explained using FIG. 11(c). FIG. 11(c) shows the transmission timing of a Qi packet defined in the WPC standard, where 1103 is a CE packet, which is one type of Qi packet. Time t_delay is the time required after transmitting the CE packet 1103 via in-band communication for the fluctuations in the current flowing through the transmitting coil 205 of tX101 or the applied voltage due to modulation to stabilize. Furthermore, during time t_active, TX101 adjusts the power level based on the Control Error Value included in the CE packet 1103. Here, time t_active is set after time t_delay, which starts from the end of the CE packet. In other words, TX101 does not perform any power level adjustment during time t_delay. Here, t_delay is the Power Control Hold-off Time defined in the WPC standard. The Power Control Hold-off Time is indicated by the Power Control Hold-off value. This Power Control Hold-off value is written in the Power Transfer Contract, which describes parameters related to power transmission / reception and communication shared between the TX 101 and the RX 102. A constraint specific to in-band communication in the TX 101 is the power level control timing related to the time t_delay. By setting this constraint, the TX 101 can perform power level control in a state where the current or voltage of the transmitting coil 205 is stable after the time t_delay. Note that the vertical axis in Figure 11(c) represents power, and Figure 11(c) shows a case where the RX 102 requests an increase in power by a CE packet 1103.

[0074] Furthermore, when transmitting a Qi packet 1104, RX 101 starts transmitting the preamble of the Qi packet 1104 after the time t_delay+t_control has elapsed since the end of the immediately preceding CE packet 1103. In this case, 1104 is a Qi packet of a different type from the CE packet. Alternatively, when transmitting a Qi packet 1104, RX 101 starts transmitting the preamble of the Qi packet 1104 later than the time t_delay+t_control since the end of the immediately preceding CE packet 1103. In other words, RX 101 does not start transmitting the preamble of any packet during the time t_delay+t_control. In FIG. 11(c), at least the time t_delay+t_control is the waiting period for signal transmission. The constraint specific to in-band communication in FIG. 11(c) is the packet transmission timing related to the time t_delay+t_control. Here, t_control is the time t_active plus the time required for fluctuations in the current or voltage of the transmitting coil 205 resulting from adjusting the power level during the time t_active to stabilize. By imposing this constraint, the RX 101 can start transmitting the preamble of the Qi packet 1104 after the current of the transmitting coil 205 has stabilized, thereby enabling stable in-band communication. In addition, a constraint may be imposed that the RX 101 starts transmitting the beginning of the next Qi packet 1104 within the time t_interval1 starting from the beginning of the previous CE packet 1103.

[0075] FIG. 11(d) shows the timing when the TX 102 controls the power level of a BLE packet 1113 containing a CE packet received via BLE communication. In FIG. 11(d), the time t_delay is not present. This is because the time t_delay is provided to stabilize fluctuations in the current or voltage of the transmitting coil 205 due to in-band communication. The TX 101 adjusts the power level based on the Control Error Value included in the CE packet during the time t_active, which starts at the end of the BLE packet 1113 containing the CE packet. In this way, BLE communication eliminates fluctuations in the current or voltage of the transmitting coil 205 due to communication. Therefore, BLE communication can achieve high-speed power control without imposing constraints specific to in-band communication. Note that the vertical axis in FIG. 11(d) represents power, and FIG. 11(c) shows a case where the RX 102 requests an increase in power via the BLE packet 1113 containing a CE packet.

[0076] Furthermore, when transmitting a BLE packet 1114 including a Qi packet, the RX102 starts transmitting the preamble of the BLE packet 1114 including the Qi packet after the time t_control has elapsed from the end of the immediately preceding BLE packet 1113 including a CE packet. In this case, 1114 is a Qi packet of a different type from the CE packet. Alternatively, when transmitting a BLE packet 1114 including a Qi packet, the RX102 starts transmitting the preamble of the BLE packet 1114 including the Qi packet later than the time t_contol from the end of the immediately preceding BLE packet 1113 including a CE packet. In FIG. 11(d), at least the time t_contol is the waiting period for signal transmission. In this way, when performing BLE communication, high-speed control can be achieved by not imposing constraints specific to in-band communication.

[0077] (System Operation) 4, 5, and 9, the operation of the system configured with the TX101 and the RX102 will be described. Here, the subsequent operation will be described assuming that the RX102 is placed on the charging stand 103 of the TX101. In this embodiment, the timing constraints for real-time control of transmission power that the TX101 and the RX102 must observe are as follows: That is, based on the WPC standard, t_interval1=250 ms, t_delay=5 ms, t_control=25 ms, and t_timeout=1500 ms.

[0078] First, TX101 and RX102 execute up to the I&C phase (F901, S401 to S402, S501 to S502). Here, RX102 sends ADV_IND, which includes identification information (F902), and TX101 confirms that this ADV_IND includes the RX102 identification information acquired in the I&C phase (F903). Next, TX101 sends CONNECT_IND to establish a BLE connection between TX101 and RX102 (F904, S404, S504). Next, RX102 requests that t_interval = 250 milliseconds, which is the interval at which CE packets will be transmitted in the real-time control that will be performed later, be set as the BLE Connection Interval (F906, S505). TX101 then sets this (F907, S405). After that, the WPC standard Negotiation and Calibration phases are processed between TX101 and RX102 (F908, S406 to S407, S506 to S507), and the process transitions to the Power Transfer phase.

[0079] During the first 250-millisecond Connection Interval, RX102 generates one CE packet, which is a Qi packet for real-time control, and stores it in a BLE packet (F909). RX102 transmits a BLE packet that includes only one CE packet (F910). BLE packet transmission is performed by the Notify process, as explained above. During the next Connection Interval, RX102 similarly generates a BLE packet that includes a CE packet (F911) and transmits it (F912). During the next Connection Interval, RX102 first generates a CE packet and stores it in the BLE packet (F913).

[0080] Next, one Charge Status packet, which is a Qi packet not for real-time control, is generated and added to the BLE packet (F914, S602). Because there are no more Qi packets not for real-time control to be generated (NO in S603), a BLE packet including one CE packet and one Charge Status packet is transmitted (F915).

[0081] In the next connection interval, the RX102 generates a BLE packet including a CE packet (F916) and transmits it (F917). In the subsequent connection intervals, the RX102 repeats the same processing as in the connection intervals F916 and F917.

[0082] After that, during a certain Connection Interval, it is detected that the battery 302 has reached full charge (F918). In this case, the RX102 generates one CE packet during that Connection Interval and stores it in the BLE packet (F919). Then, it generates one EPT packet that is not for real-time control and adds it to the BLE packet (F920). The RX102 transmits a BLE packet that includes one CE packet and one EPT packet (F921). As described in FIG. 10(C), when the RX102 transmits the EPT packet, the Power Transfer phase ends. Because the TX101 and RX102 are performing outband communication via BLE, this is disconnected and the communication ends (F922, YES in S409, S410, YES in S509, S510).

[0083] Note that when the battery 302 reaches full charge (F918), the RX102 may not generate a CE packet and may not store the CE packet in the BLE packet. The Qi packet stored in this BLE packet is only an EPT packet. Also, when the battery 302 reaches full charge (F918), the RX102 may not transmit a BLE packet. Even in these configurations, the next CE packet is not received by the TX101, so a timeout occurs and power transmission is stopped.

[0084] Here, we will explain the processing of TX101 in the Power Transfer phase. First, we will explain the processing of TX101 when receiving BLE packets that include CE packets, such as F910 and F912. TX101 recognizes that the BLE packets received in that Connection Interval include one Qi packet. TX101 then reads that one Qi packet, i.e., the CE packet, from the BLE packet and processes it without any restrictions specific to in-band communication. This processing controls the transmission power based on the Control Error Value included in the CE packet. After that, since reading all Qi packets has been completed, processing for that Connection Interval ends.

[0085] Next, the processing of the TX101 when receiving a BLE packet including one CE packet and a Charge Status packet, which is another Qi packet, as in F915, will be described. The TX101 recognizes that the BLE packet received in that Connection Interval includes two Qi packets. The TX101 then reads and processes the first Qi packet, i.e., the CE packet, from the BLE packet. This processing controls the transmission power based on the Control Error Value included in the CE packet. Next, the Charge Status packet is read and processed. This processing performs a display on the display unit 208 based on the Charge Status Value included in the Charge Status packet. After that, since reading of all Qi packets has been completed, the processing for that Connection Interval ends.

[0086] Here, in F906, RX102 sets the Connection Interval to the same interval as t_interval, the scheduled transmission interval for CE packets. In other words, using out-of-band BLE communication between TX101 and RX102, the real-time control of transmitted power described in Figure 11(c) can be repeated at t_interval = 250 ms, which RX102 has predetermined. Also, because BLE packets containing CE packets arrive every 250 ms, the CE packets will not time out if the interval is longer than t_timeout = 1500 ms. Furthermore, a BLE packet transmitted by RX102 at a 250 ms interval contains only one CE packet at most. During F930, TX101 can receive and process Qi packets, such as Charge Status packets, that are not used for real-time control, while performing real-time control using CE packets.

[0087] Second Embodiment In this embodiment, when outband communication is performed, the timing for real-time control of transmission power is changed to a value different from that used in inband communication. Here, the timing refers to, for example, t_interval and t_timeout described in the first embodiment. FIG. 12 is a diagram illustrating the processing flow of the TX 101 in the second embodiment. The second embodiment differs from the first embodiment described in FIG. 4 in the following respects: That is, when BLE communication with the RX 102 is possible, processing (S1201) for changing the timing of real-time control is added, and after BLE communication is terminated, processing (S1202) for restoring the timing of real-time control to the state before the change is added. In this embodiment, the TX 101 stores, in the memory 210, timing information for when real-time control is performed in inband communication and timing information for when real-time control is performed in outband communication. When outband communication is performed, real-time control is performed using the latter timing information.

[0088] The same applies to the RX102. Figure 13 is a diagram illustrating the flow of processing by the RX102 in the second embodiment. The difference from the first embodiment described in Figure 5 is as follows. That is, when BLE communication with the TX101 is possible, processing (S1301) for changing the timing of real-time control is added, and after BLE communication is terminated, processing (S1302) for returning the timing of real-time control to the state before it was changed is added. In this embodiment, the TX101 stores, in the memory 310, timing information for when real-time control is performed by in-band communication and timing information for when real-time control is performed by out-band communication. When out-band communication is performed, real-time control is performed using the latter timing information.

[0089] In this embodiment, the TX 101 changes the timing of real-time control after step S404 shown in Fig. 4 (S1201). Specifically, the timing of real-time control is changed based on the timing information of real-time control when performing outband communication stored in memory 210. Here, the TX 101 and RX 102 set the real-time control timing when performing outband communication to shorter values ​​than when performing inband communication. For example, when performing inband communication, t_interval is set to 250 milliseconds and t_timeout is set to 1500 milliseconds. On the other hand, when performing outband communication, t_interval is set to 100 milliseconds and t_timeout is set to 500 milliseconds.

[0090] 4, the TX 101 returns the timing of real-time control to the original state (S1202). Specifically, the TX 101 changes the timing of real-time control based on the timing information of real-time control for in-band communication stored in the memory 210.

[0091] 5, the RX102 changes the timing of real-time control (S1301). Specifically, the timing of real-time control is changed based on the timing information of real-time control for out-of-band communication stored in the memory 310. Then, the RX102 returns the timing of real-time control to its original state (S1302) after the step of S510 shown in Fig. 5. Specifically, the timing of real-time control is changed based on the timing information of real-time control for in-band communication stored in the memory 310.

[0092] With the above configuration, when high-speed communication is possible via out-of-band communication, more responsive control can be achieved by shortening the timing of real-time control of transmitted power and shortening the control period. Furthermore, because the timing change only applies to the period from the start to the end of out-of-band communication, real-time control using in-band communication can be performed as before. This ensures backward compatibility with the TX101 and RX102, which do not have out-of-band communication.

[0093] Note that the timing information to which different values ​​are applied for outband communication and inband communication may be timing information other than the above t_interval and t_timeout. Furthermore, timing other than real-time control of transmission power may be changed. For example, the overall timeout period from the start to the end of the calibration phase may be set to 10 seconds for inband communication and 5 seconds for outband communication. The same applies to the negotiation phase and other phases. As a result, if high-speed communication can be performed in outband communication, the timeout determination can be made earlier, and, for example, an error notification to the user can be made earlier.

[0094] <Other embodiments> In the above embodiment, the timing control regarding packet transmission by the RX 102 has been described, but the same effect can be obtained by regarding this as timing control regarding packet transmission by the TX 101.

[0095] Furthermore, the TX101 and RX102, which comply with the WPC standard, communicate using a 100 kHz frequency band for in-band communication, but use BLE, which uses the 2.4 GHz band, for out-band communication. Therefore, the length (time) from the beginning to the end of a packet containing the same amount of data is shorter for out-band communication than for in-band communication. Therefore, while the time t_start1 in Figure 11(a) and the time t_start2 in Figure 11(b) are described as having the same length, the length of time t_start2 may be shorter than the length of time t_start1. Similarly, the time t_interval1 in Figure 11(c) and the time t_interaval2 in Figure 11(d) are described as having the same length, the length of time t_interaval2 may be shorter than the length of time t_interval1.

[0096] 11(b), it has been described that the RX 101 may start transmitting the preamble of the BLE packet 1112 including the next Qi packet from the end of the BLE packet 1111 including the Qi packet. However, the RX 101 may wait for at least a time t (t is defined in the BLE standard, for example, a connection interval) from the end of the BLE packet 1111 before transmitting.

[0097] 11(d), the RX 102 has been described as starting transmission of the preamble of the BLE packet 1114 including a Qi packet after the time t_control from the end of the BLE packet 1113 including the immediately preceding CE packet. However, the RX 102 may wait for at least the time t (t is, for example, a connection interval defined in the BLE standard) from the end of the BLE packet 1113 before transmission.

[0098] Furthermore, the RX101 may start transmitting the preamble of the BLE packet 1114 including the Qi packet after the time t_active from the end of the BLE packet 1113 including the immediately preceding CE packet. This is because t_control is the time t_active plus the time required for the fluctuations in the current or voltage of the transmitting coil 205 to stabilize, and the time required for stabilization is not required when out-of-band communication is used. However, if the next Qi packet is a Received Power packet (hereinafter referred to as an "RP packet"), it is better to start transmitting the preamble of the BLE packet 1114 including the RP packet after at least the time t_control has elapsed. This is because the RP packet stores a value indicating the received power value. The received power value is measured during the period t_window, which begins at the beginning of the RP packet and ends before the time t_offset. The TX101 controls the power level so that the period t_window does not overlap with the period t_active, during which the power level becomes unstable, allowing accurate received power measurement.

[0099] The present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0100] The power transmitting device 101 and the power receiving device 102 may be, for example, an image input device such as an imaging device (such as a camera or a video camera) or a scanner, or an image output device such as a printer, a copier, or a projector. They may also be storage devices such as a hard disk drive or a memory device, or information processing devices such as a personal computer (PC) or a smartphone.

[0101] At least some of the flowcharts shown in Figures 4, 5, 6, 7, 11, and 12 may be implemented by hardware. In this case, for example, a specific compiler may be used to automatically generate a dedicated circuit on an FPGA from a program for implementing each step. Alternatively, a gate array circuit may be formed in the same manner as an FPGA and implemented as hardware.

[0102] The power receiving device of the present disclosure may also be an information terminal device. For example, the information terminal device has a display unit (display) that receives power from a power receiving antenna and displays information to a user. The power received from the power receiving antenna is stored in a power storage unit (battery), and power is supplied from the battery to the display unit. In this case, the power receiving device may have a communication unit that communicates with other devices different from the power transmitting device. The communication unit may be compatible with communication standards such as NFC communication and the fifth generation mobile communication system (5G).

[0103] The power receiving device of the present disclosure may also be a vehicle such as an automobile. For example, the automobile serving as the power receiving device may receive power from a charger (power transmitting device) via a power transmitting antenna installed in a parking lot. The automobile serving as the power receiving device may also receive power from the charger (power transmitting device) via a power transmitting antenna embedded in the road. In such an automobile, the received power is supplied to a battery. The battery power may be supplied to a driving unit (motor, electric unit) that drives the wheels, or may be used to drive a sensor used for driving assistance or a communication unit that communicates with an external device. In other words, in this case, the power receiving device may include, in addition to the wheels, a battery, a motor or sensor that is driven using the received power, and a communication unit that communicates with devices other than the power transmitting device. Furthermore, the power receiving device may have a storage unit for accommodating a person. For example, the sensor may be a sensor used to measure the distance between vehicles or the distance to other obstacles. The communication unit may be compatible with, for example, a global positioning system (Global Positioning Satellite, GPS). The communication unit may be compatible with communication standards such as the fifth generation mobile communication system (5G), etc. The vehicle may be a bicycle or a motorcycle.

[0104] The power receiving device of the present disclosure may also be an electric tool, a home appliance, or the like. These devices, which are power receiving devices, may have a battery and a motor that is driven by the received power stored in the battery. These devices may also have a notification means for notifying the user of the remaining battery charge, etc. These devices may also have a communication unit that communicates with other devices different from the power transmitting device. The communication unit may be compatible with communication standards such as NFC and the fifth generation mobile communication system (5G).

[0105] The power transmitting device of the present disclosure may also be an on-board charger that transmits power to a mobile information terminal device, such as a smartphone or tablet, that supports wireless power transmission within the vehicle. Such an on-board charger may be installed anywhere within the vehicle. For example, the on-board charger may be installed in the console of the vehicle, on the instrument panel (instrument panel, dashboard), between passenger seats, on the ceiling, or in the door. However, it is preferable that the on-board charger is not installed in a location that interferes with driving. Furthermore, although the power transmitting device has been described using the example of an on-board charger, such chargers are not limited to those installed in vehicles, and may also be installed in transportation vehicles such as trains, airplanes, and ships. In this case, the charger may also be installed between passenger seats, on the ceiling, or in the door.

[0106] The power transmitting device may also be a vehicle such as an automobile equipped with an on-board charger. In this case, the power transmitting device has wheels and a battery, and supplies power to the power receiving device via a power transmitting circuit unit and a power transmitting antenna using power from the battery. [Explanation of symbols]

[0107] 101 Power transmission equipment 102 Power receiving device 301 Control Unit 303 Power receiving unit 306 First Communications Department 307 Second Communications Department

Claims

1. power receiving means for wirelessly receiving power from the power transmitting device via a first antenna; a first communication means for communicating via the first antenna; second communication means for performing communication via a second antenna different from the first antenna; a control unit that controls communication with the power transmitting device using either the first communication unit or the second communication unit, The control means When communicating with the power transmitting device using the first communication means, the first communication means is controlled so that, after transmitting a signal, a next signal is transmitted after at least a specific period during which transmission is prohibited has elapsed; When communicating with the power transmitting device using the second communication means, the second communication means is controlled so that, after transmitting a signal, a next signal is transmitted even if the specific period has not elapsed; The control means when communicating with the power transmitting device using the first communication means, controlling the first communication means so that after transmitting a signal for controlling power, a next signal is transmitted after a waiting period including at least a specific period different from the specific period has elapsed; When communicating with the power transmitting device using the second communication means, the second communication means is controlled so that, after transmitting a signal for controlling power, a next signal is transmitted after a waiting period not including the other specific period has elapsed; The power receiving device is characterized in that the other specific period is a Power Control Hold-off time defined in the WPC standard.

2. 2. The power receiving device according to claim 1, wherein the control means controls the first communication means so that transmission of a preamble of a next signal is not started within the specific period.

3. 3. The power receiving device according to claim 1, wherein the specific period is a silent time defined by the Wireless Power Consortium (WPC) standard.

4. 4. The power receiving device according to claim 1, wherein the signal for controlling the power is a Control Error packet defined in the WPC standard.

5. 5. The power receiving device according to claim 1, wherein the second communication unit communicates in accordance with Bluetooth (registered trademark) Low Energy, which is defined in Bluetooth (registered trademark) 4.0 or later standards.

6. a battery that stores the power received by the power receiving means; The power receiving device according to claim 1 , further comprising: a motor for driving wheels using the electric power of the battery.

7. a battery that stores the power received by the power receiving means; 7. The power receiving device according to claim 1, further comprising: a display unit to which power from the battery is supplied.

8. a battery that stores the power received by the power receiving means; The power receiving device according to claim 1 , further comprising: a notification unit that notifies the user of the remaining charge of the battery.

9. A control method for a power receiving device having a power receiving means that wirelessly receives power from a power transmitting device via a first antenna, a first communication means that performs communication via the first antenna, and a second communication means that performs communication via a second antenna different from the first antenna, When communicating with the power transmitting device using the first communication means, the first communication means is controlled so that, after transmitting a signal, a next signal is transmitted after at least a specific period during which transmission is prohibited has elapsed; When communicating with the power transmitting device using the second communication means, the second communication means is controlled so that, after transmitting a signal, a next signal is transmitted even if the specific period has not elapsed; when communicating with the power transmitting device using the first communication means, controlling the first communication means so that after transmitting a signal for controlling power, a next signal is transmitted after a waiting period including at least a specific period different from the specific period has elapsed; When communicating with the power transmitting device using the second communication means, the second communication means is controlled so that, after transmitting a signal for controlling power, a next signal is transmitted after a waiting period not including the other specific period has elapsed; The control method is characterized in that the other specific period is a Power Control Hold-off time defined in the WPC standard.

10. A program that causes a computer to function as the power receiving device according to any one of claims 1 to 8.

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