Power receiving device and method

Abstract

To provide a power receiving device for wireless power transmission that performs device authentication using appropriate communication.SOLUTION: In a wireless power transmission system, a power receiving device that wirelessly receives a power from a power transmitting device transmits identification information of the power receiving device to the power transmitting device at a first frequency, transmits a request for performing communication at a second frequency higher than the first frequency to the power transmitting device at the first frequency after transmission of the identification information, performs communication related to authentication processing for the power transmitting device at the second frequency after transmission of the request, and performs negotiation processing related to power received from the power transmitting device after the authentication processing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a power receiving device for wireless power transmission. [Background technology]

[0002] Technological development of wireless power transmission systems has been widely conducted. Patent Document 1 discloses a power transmitter and a power receiver that comply with the standard (WPC standard) established by the Wireless Power Consortium (WPC), a standardization organization for wireless charging standards. The power transmitter and the power receiver in Patent Document 1 exchange control information necessary for controlling power transmission via so-called in-band communication, in which control information is superimposed on the transmitted and received power. Patent Document 2 also discloses a device authentication method between a power transmitter and a power receiver that perform wireless charging. According to Patent Document 2, the power transmitter transmits challenge data to the power receiver via a power transmitting coil, and the power receiver performs authentication calculations on the challenge data to generate response data, which is then transmitted to the power transmitter via a power receiving coil. The power transmitter then executes a device authentication protocol by verifying the response data received from the power receiver. Furthermore, Patent Document 3 proposes a technology in which control signals transmitted and received between the power transmitter and the power receiver are transmitted via so-called out-band communication, using a frequency or coil (or antenna) different from that used for wireless power transmission. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-007116 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-104097 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-217224 Summary of the Invention [Problem to be solved by the invention]

[0004] Because communication for device authentication involves a large amount of data, it is preferable to perform the communication using out-band communication, which enables faster communication than in-band communication. However, even if a power receiving device has an out-band communication function, the out-band communication function of the power receiving device may be disabled when the user places the power receiving device on the power transmitting device. In this case, device authentication is performed using in-band communication, which takes a long time to complete.

[0005] The present invention provides a technique for performing device authentication using appropriate communication. [Means for solving the problem]

[0006] A power receiving device according to one embodiment of the present invention comprises a power receiving means for wirelessly receiving power from a power transmitting device, a power receiving means for wirelessly receiving power from the power transmitting device, and a communication means for communicating with the power transmitting device, wherein the communication means transmits identification information of the power receiving device to the power transmitting device at a first frequency, and after transmitting the identification information, transmits a request to the power transmitting device at the first frequency to communicate at a second frequency higher than the first frequency, and after transmitting the request, communicates at the second frequency regarding an authentication process with the power transmitting device, and the power receiving device further comprises means for performing a negotiation process regarding the power to be received from the power transmitting device after the authentication process. [Effects of the Invention]

[0007] According to the present invention, device authentication can be performed using appropriate communication. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the configuration of a wireless power transmission system according to an embodiment; [Figure 2] FIG. 1 is a block diagram showing an example of the configuration of a power receiving device according to an embodiment. [Figure 3] FIG. 1 is a block diagram showing an example of the configuration of a power transmitting device according to an embodiment. [Figure 4]10 is a flowchart showing an example of a processing flow of a power receiving device. [Figure 5] 10 is a flowchart showing an example of the flow of a process for determining whether to start BLE communication. [Figure 6] 10 is a flowchart showing an example of a processing flow of a power transmitting device. [Figure 7] (A) is a diagram showing the communication sequence for device authentication, (B) is a diagram showing the communication sequence of the I&C phase, and (C) is a diagram showing the communication sequence of the Negotiation phase. [Figure 8] FIG. 10 is a diagram showing an example of the configuration of a Power Transmitter Capability Packet. [Figure 9] FIG. 10A is a diagram showing an example of a display for inquiring about permission for BLE ON, and FIG. 10B is a diagram showing an example of a display for presetting permission for BLE ON. [Figure 10] 4 is a diagram showing a first example of processing executed in the wireless power transmission system according to the embodiment; [Figure 11] FIG. 10 is a diagram illustrating a second processing example executed in the wireless power transmission system according to the embodiment. [Figure 12] FIG. 10 is a diagram illustrating a third example of processing executed in the wireless power transmission system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, 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, and redundant explanations will be omitted.

[0010] (1) System configuration 1 shows an example of the configuration of a wireless power transmission system according to this embodiment. In one example, the wireless power transmission system according to this embodiment includes a power receiving device 101 and a power transmitting device 102, and constitutes a wireless charging system in which the power receiving device 101 is charged by power supplied from the power transmitting device 102 to the power receiving device 101 via wireless power transmission. The power receiving device 101 is an electronic device that receives power from the power transmitting device 102 and charges an internal battery. The power transmitting device 102 is an electronic device that wirelessly transmits power to an RX placed on a charging stand 103. Hereinafter, the power receiving device 101 may be referred to as an RX, and the power transmitting device 102 may be referred to as a TX.

[0011] 104 is the range over which RX can receive power from TX. Note that RX and TX may have a function to execute applications other than wireless charging. An example of RX is a smartphone, and an example of TX is an accessory device for charging the smartphone. RX and TX may be storage devices such as hard disk drives and memory devices, or may be information processing devices such as personal computers (PCs). Furthermore, RX and TX may be, for example, image input devices such as imaging devices (cameras, video cameras, etc.) and scanners, or may be image output devices such as printers, copiers, projectors, etc.

[0012] 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, wireless power transmission for wireless charging based on the WPC standard is performed between the RX power receiving coil and the TX power transmitting coil. Note that the wireless power transmission method (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. Furthermore, in this embodiment, wireless power transmission is used for wireless charging, but wireless power transmission may also be performed for purposes other than wireless charging.

[0013] In the WPC standard, the amount of power guaranteed when an RX receives power from a TX is specified by a value called Guaranteed Power (hereinafter referred to as "GP"). GP indicates the power value guaranteed to be output to the RX load (e.g., a charging circuit) even if, for example, the relative positions of the RX and TX change and the power transmission efficiency between the receiving coil and the transmitting coil decreases. For example, if the GP is 5 watts, the TX will transmit power by controlling it so that it can output 5 watts to the load in the RX, even if the relative positions of the receiving coil and the transmitting coil change and the power transmission efficiency decreases.

[0014] The RX and TX according to this embodiment perform communication for power transmission and reception control based on the WPC standard and communication for device authentication.

[0015] First, we will explain the communication for power transmission and reception control based on the WPC standard. The WPC standard specifies multiple phases, including a phase before actual power transmission and a power transfer phase in which power transmission is performed, and communication for the 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 TX intermittently transmits Analog Pings to detect the presence of an object within the power transmission range (for example, that the RX or a conductor piece has been placed on the charging stand 103). In the Ping phase, the TX transmits Digital Pings and recognizes that the detected object is the RX by receiving a response from the RX that has received the Digital Ping. In the I&C phase, the RX notifies the TX of its identification information and capability information. In the Negotiation phase, the GP value is determined based on the GP value requested by the RX and the power transmission capability of the TX. In the Calibration phase, the RX notifies the TX of the received power value based on the WPC standard, and the TX makes adjustments to transmit power efficiently. In the Power Transfer phase, in which wireless power transmission is performed, control is performed to continue power transmission and to stop power transmission due to an error or full charge, etc.

[0017] The TX and RX communicate to control power transmission and reception using in-band communication, which superimposes signals using the same antenna (coil) as for wireless power transmission, based on the WPC standard. The range in which in-band communication based on the WPC standard is possible between the TX and RX is approximately the same as the power transmission range. Therefore, range 104 in FIG. 1 represents the range in which wireless power transmission and in-band communication are possible using the power transmitting and receiving coils of the TX and RX. In the following description, the expression "placed" on the RX means that the RX has entered the range 104, and also includes a state in which the RX is not actually placed on the charging stand 103.

[0018] Prior to determining the GP, the RX according to this embodiment performs challenge-response communication with the TX using a digital certificate to perform device authentication of the TX. That is, communication for device authentication is performed prior to determining the GP. Then, the RX determines the GP to request from the TX in the negotiation phase based on the results of the device authentication. For example, the RX requests a GP of 15 watts from a TX that has been successfully authenticated, and requests a GP of 5 watts from a TX that has not.

[0019] Note that the GP when device authentication is successful and when it is not is not limited to the combination of 15 watts and 5 watts. Any value can be used as long as the GP with a TX that has been successfully authenticated is greater than the GP when device authentication is not successful. In other words, the RX transmits and receives power at a larger GP only with a TX that has been successfully authenticated. By determining the GP based on the results of device authentication in this way, the RX can receive power at a larger GP only from a TX that has passed a specified test defined in the WPC standard or the like and is recognized as being capable of transmitting power at a larger GP.

[0020] In this embodiment, RX and TX perform communication for device authentication using either out-of-band communication, which uses an antenna and frequency separate from those for wireless power transmission, or in-band communication, which uses the same antenna (coil) as for wireless power transmission and superimposes signals. Here, out-of-band communication is capable of faster communication than in-band communication. RX performs communication for device authentication using out-of-band communication if TX is capable of out-of-band communication, and otherwise performs communication for device authentication using in-band communication. This process will be described later.

[0021] In this embodiment, a communication method conforming to the Bluetooth (registered trademark) Low Energy (hereinafter referred to as "BLE") standard is used as an example of outband communication. It is assumed that the TX operates as a BLE peripheral and the RX operates as a BLE central, but these BLE roles may be reversed. The communication method for outband communication is not limited to BLE. For example, outband communication may be performed using a communication method such as a wireless LAN (e.g., Wi-Fi (registered trademark)) in the IEEE 802.11 standard series, ZigBee, or NFC (Near Field Communication). It is assumed that when the TX is capable of outband communication and the RX is within range 104, the RX and TX can exchange information via outband communication.

[0022] (2) Equipment configuration Next, the configurations of the power receiving device 101 (RX) and the power transmitting device 102 (TX) according to this embodiment will be described. Note that the configurations described below are merely examples, and part (or in some cases the entirety) 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.

[0023] 2 is a diagram showing an example of the configuration of an RX according to this embodiment. In one example, the RX includes a control unit 201, a battery 202, a power receiving unit 203, a detection unit 204, a power receiving coil 205, a first communication unit 206, a second communication unit 207, a display unit 208, an operation unit 209, a memory 210, a timer 211, and a charging unit 212.

[0024] The control unit 201 executes a control program stored in the memory 210, for example, to control the entire RX and execute various processes described below. In one example, the control unit 201 performs control necessary for device authentication and power reception in the RX. The control unit 201 may also perform control for executing applications other than wireless power transmission. The control unit 201 includes one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 201 may also include hardware dedicated to specific processes, such as an application-specific integrated circuit (ASIC), or 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 executing various processes in the memory 210. The control unit 201 may also measure time using a timer 211.

[0025] The battery 202 supplies the entire RX with power required for control, power reception, and communication, for example. The battery 202 also stores power received via the power receiving coil 205. In the power receiving coil 205, an induced electromotive force (AC power due to electromagnetic induction) is generated by electromagnetic waves radiated from the power transmitting coil 305 (FIG. 3) of the TX. The power receiving unit 203 acquires the AC power generated by electromagnetic induction in the power receiving coil 205. The power receiving unit 203 then converts the AC power into DC or AC power of a predetermined frequency, and supplies power to each unit of the RX, including the charging unit 212. The charging unit 212 performs processing to charge the battery 202. In this way, the power receiving unit 203 supplies power to the load in the RX. The above-mentioned GP is the amount of power guaranteed to be output from the power receiving unit 203.

[0026] The detection unit 204 detects whether the RX is placed within the range 104 in which it can receive power from the TX, based on the WPC standard. The detection unit 204 detects, for example, the voltage value or current value of the power receiving coil 205 when the power receiving unit 203 receives a Digital Ping of the WPC standard via the power receiving coil 205. The detection unit 204 determines that the RX is placed within the range 104, for example, when the voltage upon receiving the Digital Ping is below a predetermined voltage threshold or the current value exceeds a predetermined current threshold.

[0027] The first communication unit 206 performs control communication with the TX based on the WPC standard as described above through in-band communication. The first communication unit 206 demodulates the electromagnetic waves input from the power receiving coil 205 to acquire information transmitted from the TX, and performs load modulation on the electromagnetic waves to superimpose information to be transmitted to the TX onto the electromagnetic waves, thereby performing communication with the TX. In other words, the communication performed by the first communication unit 206 is superimposed on power transmission from the power transmitting coil 305 of the TX.

[0028] The second communication unit 207 performs communication for device authentication with the TX via out-band communication. Note that the second communication unit 207 may also perform communication other than communication for device authentication. The second communication unit 207 has a modulation / demodulation circuit and a communication protocol processing function required for communication compliant with the BLE standard, for example.

[0029] 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, the status of RX or the status of the wireless power transmission system including TX and RX as shown in FIG. 1. The display unit 208 includes, for example, an LCD display, an LED, a speaker, a vibration generating circuit, or other notification devices. The operation unit 209 has a function of accepting an operation for RX from the user. The operation unit 209 includes, 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. Note that a device in which the display unit 208 and the operation unit 209 are integrated, such as a touch panel, may also be used. The memory 210 stores various information as described above. Note that the memory 210 may store information obtained by a functional unit other than 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.

[0030] 3 is a block diagram showing an example of the configuration of the TX according to this embodiment. In one example, the TX includes a control unit 301, a power supply unit 302, a power transmission unit 303, a detection unit 304, a power transmission coil 305, a first communication unit 306, a second communication unit 307, a display unit 308, an operation unit 309, a memory 310, and a timer 311.

[0031] The control unit 301 executes a control program stored in the memory 310, for example, to control the entire TX and execute various processes described below. In one example, the control unit 301 performs device authentication and control necessary for power transmission in the TX. The control unit 301 may also perform control for executing applications other than wireless power transmission. The control unit 301 includes one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 301 may also include hardware dedicated to specific processes, such as an application-specific integrated circuit (ASIC), or an array circuit, such as an FPGA (Field Programmable Gate Array) compiled to execute predetermined processes. The control unit 301 stores information to be stored while executing various processes in the memory 310. The control unit 301 may also measure time using a timer 311.

[0032] The power supply unit 302 supplies the entire TX with power (DC or AC power) required for control, power transmission, and communication. The power supply unit 302 is, for example, a commercial power supply or a battery.

[0033] The power transmitting unit 303 converts DC or AC power input from the power supply unit 302 into AC power in a frequency band used for wireless power transmission, and inputs the AC power to the power transmitting coil 305 to generate electromagnetic waves for the RX to receive power. The frequency of the AC power generated by the power transmitting unit 303 is approximately several hundred kHz (e.g., 110 kHz to 205 kHz), which is different from the BLE communication frequency (2.4 GHz) used in out-band communication. Based on instructions from the control unit 301, the power transmitting unit 303 inputs AC power to the power transmitting coil 305 so that the power transmitting coil 305 outputs electromagnetic waves for transmitting power to the RX. The power transmitting unit 303 also controls the intensity of the electromagnetic waves to be output by adjusting the voltage (transmission voltage) or current (transmission current) input to the power transmitting coil 305. Increasing the transmission voltage or transmission current increases the intensity of the electromagnetic waves, whereas decreasing the transmission voltage or transmission current decreases the intensity of the electromagnetic waves. Furthermore, based on instructions from the control unit 301, the power transmitting unit 303 controls the output of AC power so that power transmission from the power transmitting coil 305 is started or stopped.

[0034] The detection unit 304 detects whether an object is present or placed in the range 104 based on the WPC standard. For example, the detection unit 304 detects the voltage value or current value of the power transmitting coil 305 when the power transmitting unit 303 transmits an Analog Ping of the WPC standard via the power transmitting coil 305. Then, the detection unit 304 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 an RX or another foreign object is determined based on whether a predetermined response is received in response to a Digital Ping that is subsequently transmitted by the first communication unit 306 via in-band communication. When a predetermined response is received in response to the Digital Ping, it is determined that an RX is present.

[0035] The first communication unit 306 performs control communication based on the WPC standard as described above with the RX through in-band communication. The first communication unit 306 modulates the electromagnetic waves output from the power transmitting coil 305 and transmits information to the RX. The first communication unit 306 also demodulates the electromagnetic waves output from the power transmitting coil 305 and modulated by the RX to acquire information transmitted by the RX. In this way, communication performed by the first communication unit 306 is superimposed on power transmission from the power transmitting coil 305.

[0036] The second communication unit 307 performs communication for device authentication with the RX via out-band communication. Note that the second communication unit 307 may also perform communication other than communication for device authentication. The second communication unit 307 has a modulation / demodulation circuit and a communication protocol processing function required for communication compliant with the BLE standard, for example.

[0037] 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 the TX or the status of the wireless power transmission system including the TX and RX as shown in FIG. 1 . The display unit 308 includes, for example, an LCD display, an LED, a speaker, a vibration generating circuit, or other notification devices. The operation unit 309 has a function of accepting operations for the TX from the user. The operation unit 309 includes, 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. Note that a device in which the display unit 308 and the operation unit 309 are integrated, such as a touch panel, may also be used. The memory 310 stores various information as described above. Note that the memory 310 may store information obtained by a functional unit other than the control unit 301. The timer 311 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.

[0038] (3) Processing flow Next, an example of the flow of processing executed by the RX and TX will be described.

[0039] [3.1] Processing in the power receiving device 101 (RX) FIG. 4 is a flowchart showing an example of processing executed by the RX. This processing can be implemented, for example, by the control unit 201 of the RX 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 RX is started up by power supply from the battery 202 or the TX in response to the power supply of the RX being turned on, or when the user of the RX inputs a command to start a wireless charging application. This processing may also be started by some other trigger.

[0040] After starting the process, the RX 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 TX (S401). The RX detects that it has been placed on the TX, for example, by detecting a Digital Ping from the TX. When the RX detects that its own device has been placed on the TX, it transmits identification information and capability information to the TX via in-band communication in the I&C phase defined in the WPC standard (S402).

[0041] Figure 7(B) shows the flow of communication in the I&C phase. In the I&C phase, the RX transmits an Identification Packet (ID Packet) to the TX (F711). The ID Packet stores the Manufacturer Code and Basic Device ID, which are identification information for each individual RX, as well as information elements that can identify the version of the WPC standard supported by the RX as capability information. The RX also transmits a Configuration Packet to the TX (F712). The Configuration Packet contains, as capability information for the RX, the Maximum Power Value, which specifies the maximum power that the RX can supply to a load, and information indicating whether the RX has the negotiation function of the WPC standard. Here, the RX includes, in the capability information, information indicating that BLE communication is possible (BLE communication capability information). In this way, the BLE communication capability information is transmitted as part of the capability information using the Configuration Packet. Note that the communication capability information may be transmitted in the ID Packet or another packet. Upon receiving these packets, the TX transmits an ACK (F713), and the I&C phase ends.

[0042] Note that the RX may notify the TX of its identification information and capability information by a method other than the I&C phase communication of the WPC standard. Furthermore, the identification information for each individual RX may be any other identification information capable of identifying the individual RX, such as a Wireless Power ID or a Bluetooth Address (hereinafter referred to as "BD_ADDR") unique to the second communication unit 207 of the RX. Furthermore, the capability information may include information other than the above.

[0043] Returning to Fig. 4, after S402, the RX acquires capability information from the TX through in-band communication (S403). The capability information of the TX can be acquired, for example, by a Power Transmitter Capability Packet (hereinafter referred to as "TX Capability Packet") of the WPC standard shown in Fig. 8. Of course, the capability information from the TX may also be acquired by another packet. In the following description, it is assumed that the TX Capability Packet is used as the capability information acquired from the TX.

[0044] When the RX acquires the capability information from the TX, the RX performs a BLE communication start determination process (S404). Details of the BLE communication start determination process will be described later. If it is determined that BLE communication should be started (YES in S405), the RX receives an advertising packet from the TX via the second communication unit 207 and establishes a BLE connection by transmitting a CONNECT_REQ to the BD_ADDR of the packet sender (S406). Note that the RX may acquire a BD_ADDR from the TX via in-band communication in S403, and then transmit a CONNECT_REQ directly to the BD_ADDR in S406 without waiting for an advertising packet, thereby establishing a BLE connection. Next, the RX communicates with the TX for device authentication using the BLE communication established above (S407).

[0045] Here, the contents of communication for device authentication performed between RX and TX will be explained using Fig. 7(A). In this embodiment, device authentication is a challenge-response type device authentication using a digital certificate, and RX authenticates TX. Note that TX may authenticate RX, or both may authenticate each other. RX acts as an initiator that sends a challenge text to TX, and TX acts as a responder that encrypts the challenge text received from RX and sends it to RX.

[0046] First, RX sends a GET_DIGESTS message to TX (F701). GET_DIGESTS is a message requesting information about the digital certificate held by the receiver (TX). TX sends DIGESTS to RX in response to GET_DIGESTS (F702). DIGESTS is information about the digital certificate held by the sender (TX). Next, RX sends a GET_CERTIFICATE message to TX requesting detailed information (CERTIFICATE) about the digital certificate (F703). TX sends CERTIFICATE to RX in response to the GET_CERTIFICATE from RX (F704). Then, RX sends a CHALLENGE message including a challenge text to TX (F705), and TX sends a RESPONSE, which is the encrypted version of the challenge text received from RX, to RX (F706).

[0047] If the validity of the RESPONSE received from TX is confirmed, RX transmits RESULT(Success) to TX (F707) and ends the device authentication. RESULT(Success) means that the validity of the RESPONSE was confirmed and the device authentication was successful. If the device authentication failed, RESULT(Fail) is transmitted instead of RESULT(Success), and the device authentication process ends. If the initiator (RX) receives a message indicating that the other device (TX) does not support device authentication communication, it determines that the other device does not support device authentication. If the initiator (RX) does not receive a response during communication, it may retry by resending a message to obtain the response, or it may determine that the other device does not support device authentication. RX may not perform communication for device authentication with a TX that does not support device authentication, and the result of the device authentication may not be determined to be successful.

[0048] Note that each of the above messages is sent and received using one of the predefined GATT service characteristics, Read, Write, Notify, or Indicate, in GATT communication over a BLE connection. GATT communication is performed by sending and receiving packets standardized by BLE. When the communication for device authentication is completed, the RX disconnects the BLE connection by sending a BLE LL_TERMINATE_IND. Note that the BLE connection may be disconnected first by the TX. Note that if the BLE connection is used by another application, the BLE connection may not be disconnected even after the communication for device authentication is completed. Furthermore, prior to the communication for device authentication, the RX may obtain information on whether the TX supports device authentication through a BLE advertising packet or GATT communication. If the TX does not support device authentication, the RX may determine that the TX does not support device authentication and may not perform the communication shown in Figure 7(A).

[0049] On the other hand, if BLE communication is not started after S404 (NO in S405), communication for device authentication described in Fig. 7(A) is performed using in-band communication with TX (S408). At this time, each message exchanged in the communication for device authentication is sent and received between TX and RX as an in-band communication packet.

[0050] After performing communication for device authentication via BLE or in-band communication (S407, S408), RX negotiates with TX based on the result of device authentication (S409). If device authentication is successful (YES in S409), RX negotiates to set GP to 15 watts (S410), and if not (NO in S409), RX negotiates to set GP to 5 watts (S411).

[0051] In the negotiation, communication in the negotiation phase of the WPC standard is performed, as shown in Fig. 7(C). First, RX notifies TX of the requested GP value by sending a Specific Request to TX (F721). That is, if device authentication is successful, GP = 15 watts is notified, and if not, GP = 5 watts is notified. TX determines whether to accept the request based on the power transmission capacity of its own device, and sends ACK if accepted, or NAK if not accepted, to RX (F722).

[0052] Here, if the GP size requested by RX is a size that can be transmitted with the power transmission capacity of the own device, TX accepts the request from RX. In this case, the GP value is determined to be the same as the value requested by RX. On the other hand, if the GP size requested by RX is a size that cannot be achieved with the power transmission capacity of the own device, TX does not accept the request from RX. In this case, for example, a small value predefined in the WPC standard may be determined as the GP value. Note that a small value other than the value predefined in the WPC standard may also be determined as the GP value at this time. In one example, these small values ​​are stored in advance in the RX memory 210 and the TX memory 310.

[0053] Note that if TX is capable of transmitting power to multiple RXs simultaneously and is already transmitting power to another RX, it may determine the GP value based on its current available power transmission capacity instead of its own power transmission capability. Furthermore, in S410 and S411, communication in the negotiation phase of the WPC standard is used, but this is not limiting, and other procedures for determining GP based on the results of device authentication between TX and RX may be executed. Furthermore, if TX acquires information indicating that RX does not support the negotiation phase (for example, in S402), it may not perform communication in the negotiation phase and may set the GP value to a small value (for example, specified in advance in the WPC standard).

[0054] Returning to FIG. 4, after determining the GP, the RX performs calibration (S412) and receives power until full charge (S413) based on the GP. Calibration is a process in which the TX adjusts the correlation between the value measured inside the TX and the value of received power measured inside the RX, for the power transmitted from the TX to the RX. The TX performs this process through processing in the Calibration phase of the WPC standard. Furthermore, receiving power until full charge is performed through processing in the Power Transfer phase of the WPC standard. The calibration and power reception in S412 and S413 can use procedures according to the WPC standard. However, calibration and power reception may also be performed by methods other than those according to the WPC standard.

[0055] When RX reaches full charge in the Power Transfer phase, it transmits an End Power Transfer message according to the WPC standard. This stops power transmission from TX, and the series of processes for wireless charging ends. After the series of processes for wireless charging ends, if BLE was OFF when RX was placed on TX (YES in S414), RX turns BLE OFF (S415) and ends this process. Note that if the BLE connection is used by another application, BLE does not need to be turned OFF. On the other hand, if BLE is ON (NO in S414), RX does not do anything and ends this process. After this, RX may return to S401, or may wait for another trigger to start, such as when the remaining battery charge drops below a predetermined level, before returning to S401.

[0056] 5 is a flowchart showing an example of the BLE communication start determination process (S404) executed by the RX. This process can be realized, for example, by the control unit 201 of the RX executing a program read from the memory 210. At least a part of the following procedure can be realized by hardware. In this case, the hardware can be realized, 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. Furthermore, this process can be executed in response to receiving capability information from the TX, but can also be started by some other trigger.

[0057] The RX checks whether the capability information acquired from the TX in S403 includes information indicating that device authentication via BLE communication is possible (S501). Whether or not the information indicating that device authentication via BLE communication is possible can be determined by, for example, checking a bit indicating the ability to perform device authentication using out-band communication included in the capability information, a bit indicating that BLE is held, or a bit indicating whether BLE is available. If the capability information acquired from the TX includes information indicating that device authentication via BLE communication is possible (YES in S501), the RX determines whether its own BLE is ON (whether the BLE status is valid or not) (S502). On the other hand, if the capability information acquired from the TX does not include information indicating that device authentication via BLE communication is possible (NO in S501), the RX ends this process without doing anything.

[0058] If BLE is enabled (ON) (YES in S502), the RX determines whether BLE communication by the second communication unit 207 is possible (S503). Here, if the BLE communication function is being used with another application or communication device, or if the role of the BLE communication function is Peripheral, the RX determines that BLE communication is impossible. Furthermore, the RX may determine that BLE communication is impossible if the remaining charge of the battery 202 is low. If BLE communication is possible (YES in S503), the RX transmits a BLE communication start request to the TX (S506) and ends this processing. The BLE communication start request may be made, for example, by an Out Of Band Request Packet (hereinafter referred to as an "OOB Req Packet") of the WPC standard, or by another packet. On the other hand, if BLE communication is impossible (NO in S503), the RX ends this processing without doing anything.

[0059] When BLE is disabled (BLE is not ON) (NO in S502), the RX determines whether or not the user has permitted turning on BLE (S504). The user permits turning on BLE, for example, by displaying a query display 900 as shown in FIG. 9(A) on the display unit 208 in full screen or as a pop-up window, and the user selects an area 901 instructing permission. On the other hand, BLE activation (turning on BLE) is not permitted by the user selecting an area 902 instructing denial in the query display 900. Note that the user's selection result may be stored, and if turning on BLE has been permitted by a previous operation, it may be determined that permission has been granted without displaying the query display 900.

[0060] 9(B), an item 911 regarding permission to turn on BLE may be displayed in a setting display 910 for RX, and permission may be given by the user enabling the item 911 in advance using a button 912. In this case, too, it may be determined that turning on BLE is permitted without displaying the inquiry display 900. Furthermore, if no operation is performed on the inquiry display 900 for a certain period of time, it may be determined that turning on BLE is not permitted.

[0061] If enabling BLE is permitted (YES in S504), after enabling (ON) BLE (S505), a BLE communication start request is sent to TX (S506), and this process ends. On the other hand, if turning ON BLE is not permitted (NO in S504), this process ends without doing anything.

[0062] [3.2] Processing in the power transmission device Next, an example of the flow of processing executed by the TX will be described with reference to FIG. 6. This processing can be realized, for example, by the control unit 301 of the TX executing a program read from the memory 310. At least a part of the following procedure can be realized by hardware. In this case, the hardware can be realized, 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 power of the TX is turned on, when the user of the TX inputs an instruction to start a wireless charging application, or when the TX is connected to a commercial power source and receives power. This processing can also be started by some other trigger.

[0063] In this process, the TX first executes the processes defined as the Selection phase and Ping phase of the WPC standard, and waits for the RX to be placed (S601). The TX repeatedly and intermittently transmits Analog Pings of the WPC standard to detect an object that exists within the power transmission range (Selection phase). Then, if the TX detects that an object exists within the power transmission range, it transmits a Digital Ping. If there is a predetermined response to the Digital Ping, the TX determines that the detected object is the RX and that the RX has been placed on the charging stand 103 (Ping phase).

[0064] When TX detects that RX has been placed, it executes the above-mentioned I&C phase communication via in-band communication and acquires identification information and capability information from RX (S602). Next, it waits to receive a capability information acquisition request from RX (S603). If it receives a capability information acquisition request (YES in S603), it transmits the capability information (S604). If it does not receive the request (NO in S603), it does nothing and waits to receive a BLE communication start request from RX (S605).

[0065] In this embodiment, one bit from bit 6 to bit 7 (800) of Bank 1 or bit 2 to bit 7 (801) of Bank 2, which are the reserved areas of the TX Capability Packet in FIG. 8, is assigned as the Auth bit. The Auth bit is an example of capability information. If the TX is capable of performing device authentication using outband communication, it writes "1" to the Auth bit; otherwise, it writes "0." The TX also assigns a BLE bit to one bit in the reserved area. If the TX is capable of using BLE for outband communication or is equipped with BLE that can be used for control communication, it writes "1" to the BLE bit; otherwise, it writes "0." The TX also assigns a BLE Enable bit to one bit in the reserved area. If the TX can use BLE for outband communication at that time, it writes "1" to the BLE Enable bit; otherwise, it writes "0." Note that the type of outband communication may include bits related to NFC or Wi-Fi, and is not limited to the above form.

[0066] Returning to Figure 6, when the TX receives a BLE communication start request (YES in S605), it transmits a BLE advertising packet including the TX's identification information and establishes a BLE connection with the RX installed on its own device (S606). Next, the TX performs communication for device authentication with the RX described in Figure 7(A) using the BLE connection established in S606 (S607). On the other hand, if the BLE communication start request cannot be received from the RX in S605 (NO in S605), it performs communication for device authentication described in Figure 7(A) using in-band communication (S608). Then, the TX performs negotiation with the RX as shown in Figure 7(C) and determines the GP (S609). After determining the GP, the TX performs calibration (S610) and transmits power until fully charged based on the GP (S611).

[0067] Furthermore, when TX receives an End Power Transfer of the WPC standard from RX, it ends the processing in any processing phase in accordance with the WPC standard, stops power transmission, and returns to the Selection phase of S601. Note that when the battery is fully charged, End Power Transfer is also sent from RX, so the process returns to the Selection phase of S601.

[0068] [3.3] System operation The operation sequences of RX and TX explained using Figures 4 to 6 will be explained assuming several situations. Note that in the initial state, RX is not placed on TX, and TX has sufficient power transmission capability to transmit power at the GP required by RX.

[0069] <Processing example 1> First, processing example 1 will be described with reference to Fig. 10. In processing example 1, TX is assumed to be a device that has the second communication unit 307, i.e., the function of outband communication by BLE, is capable of BLE communication, and succeeds in device authentication of RX. Also, RX is assumed to have BLE OFF when placed, is not permitted to turn BLE ON in advance, and needs to obtain permission from the user by inquiring whether or not to allow BLE ON.

[0070] First, TX waits for an object to be placed using Analog Ping (S601, F1001). When RX is placed (F1002), a change occurs in Analog Ping (F1003), and TX detects that an object has been placed (F1004). RX detects that it has been placed on TX using the subsequent Digital Ping (S401, F1005, F1006). TX also detects that the object placed on TX is RX using the Digital Ping response. Next, through communication in the I&C phase, RX notifies TX that BLE communication is possible (S402, S602, F1007). Next, RX sends a capability information acquisition request (S403, F1008), and TX sends capability information (YES in S603, S604, F1009).

[0071] When RX receives the capability information from TX, it starts the BLE communication start determination process (S404). Because the capability information from TX includes information that device authentication via BLE communication is possible, RX checks whether its own BLE is ON (YES in S501, S502). Because RX's own BLE is OFF and BLE ON has not been permitted in advance, it displays display 900 inquiring whether or not to permit BLE ON (NO in S502, F1010). When RX is permitted to turn BLE ON by the user, it turns BLE ON (YES in S504, S505, F1011) and sends a BLE communication start request to TX (S506, F1012). When TX receives the BLE communication start request, it sends a BLE advertising packet (F1013), and RX sends CONNECT_REQ (F1014), thereby establishing a BLE connection (YES in S405, S406, YES in S605, S606).

[0072] Next, communication for device authentication via BLE is performed, and device authentication is successful (S407, S607, F1015). Because device authentication is successful, negotiation between RX and TX determines GP = 15 watts (YES in S409, S410, S608, F1016). After that, calibration is performed (S412, S609, F1017) and power transmission and reception is performed until the battery is fully charged (S413, S610, F1018). When the battery is fully charged, an End Power Transfer is sent from RX, and processing ends (F1019).

[0073] According to the operation described above, when RX is placed on a TX that is capable of outband communication via BLE while its own BLE is OFF, it turns BLE ON to perform communication for device authentication, and can receive power based on the result of the device authentication.

[0074] <Processing example 2> Next, processing example 2 will be explained using Fig. 11. In processing example 2, it is assumed that the RX is not placed on the TX and the BLE is OFF as an initial state. The explanation will also be given assuming that the user has given permission to turn on the BLE in advance. The following explanation will focus on the differences from Fig. 10.

[0075] In FIG. 11, the process from detection of placement to transmission of capability information by the TX (F1101 to F1109) is the same as in FIG. 10 (F1001 to F1009). When the RX receives capability information from the TX, it starts the BLE communication start determination process (S404). Because the user has given the RX permission to turn on BLE in advance, the RX automatically turns on BLE without inquiring whether or not to allow BLE to be turned on (NO in S502, YES in S504, S505, F1110). The subsequent operations (F1011 to F1018) until full charging are the same as those in FIG. 10 (F1012 to F1019). According to the operations described above, when the RX is placed on a TX capable of outband communication using BLE, the RX automatically turns on BLE without the user being aware of the BLE status, performs communication for device authentication, and is able to receive power based on the results.

[0076] <Processing example 3> Next, processing example 3 will be described using Fig. 12. In processing example 3, it is assumed that RX is not placed on TX and BLE is OFF as an initial state. In addition, it is assumed that the user has not permitted BLE to be turned ON in advance, and there is no user operation in response to an inquiry about whether or not to permit BLE to be turned ON, so ON is not permitted. The following description will focus on the differences from Fig. 10.

[0077] In Fig. 12, the process from detection of placement to the inquiry display asking whether or not to allow BLE to be turned on (F1201 to F1210) is the same as Fig. 10 (F1001 to F1010). Since there is no user operation for a certain period of time after the inquiry display, RX ends the inquiry display and determines that turning on BLE is not permitted (NO in S504, F1211). Since turning on BLE is not permitted for RX, communication for device authentication is performed via in-band communication and is successful (NO in S405, S408, F1212). The subsequent operations (F1213 to F1216) until full charging are the same as Fig. 10 (F1016 to F1019).

[0078] According to the operation described above, when RX is placed on TX that is capable of out-band communication using BLE, and when the user does not allow BLE to be turned on, RX performs communication for device authentication using in-band communication without turning on BLE, and receives power based on the result.

[0079] As described in the above processing examples 1 to 3, even when the RX according to this embodiment is placed on a TX that is capable of out-band communication using BLE with BLE turned off, it can turn on BLE and perform communication for device authentication via out-band communication. Here, because out-band communication can communicate faster than in-band communication, the time required for communication for device authentication is shorter when out-band communication is used. Therefore, it is possible to shorten the time from when the RX is placed on the device to when charging starts. Furthermore, even if the user does not permit BLE to be turned on, communication for device authentication can be performed via in-band communication, so charging can start regardless of the BLE state.

[0080] In the present embodiment, if there is no user operation for a certain period of time in response to the inquiry about whether to allow BLE to be turned on, the inquiry display is terminated, and device authentication is performed using in-band communication as it is not permitted. However, the inquiry display does not have to be terminated. Furthermore, when the user permits BLE to be turned on during device authentication using in-band communication, device authentication using in-band communication may be interrupted, BLE may be turned on, and device authentication using out-band communication may be switched to. This reduces the time required for communication for device authentication compared to continuing device authentication using in-band communication, thereby shortening the time until charging starts. On the other hand, if the processing phase of device authentication performed over in-band communication is progressing, device authentication using in-band communication may be continued without turning BLE on. This prevents the time required for communication for device authentication from being extended due to the time required to establish a BLE connection. Furthermore, the inquiry display may be terminated when device authentication using in-band communication is completed.

[0081] In this embodiment, the case where device authentication is applied as a function using outband communication has been described. However, other functions that can be executed using outband communication may also be applied. For example, a firmware update of the TX may be applied. In this case, the TX assigns one bit from bits 6 to 7 (800) of Bank 1 or bits 2 to 7 (801) of Bank 2, which are reserved areas of the TX Capability Packet, to the Firmware Update bit. If the TX itself has the capability to perform firmware updates using outband communication, it writes "1" to the Firmware Update bit; otherwise, it writes "0." In this way, applying this to a function that requires communication with a large amount of data can significantly reduce the time required for communication for that function.

[0082] In this embodiment, the RX is described as using only one type of communication method, BLE, for outband communication. However, the RX may have the ability to communicate using multiple communication methods, and any of these may be used for outband communication. In this case, the capability information transmitted and received in S402 and S403 of FIG. 4 may include information on whether BLE communication is possible, as well as information on whether other communication methods are possible. Furthermore, in the BLE communication start determination process (S501 to S506) of FIG. 5, control may be performed to turn on communication for other communication methods if they are OFF, depending on the received capability information. As a result, for example, whether the RX is placed on a TX capable of BLE communication or a TX capable of Wi-Fi communication, device authentication can be performed in a short time using outband communication, which is faster than inband communication.

[0083] In the above embodiment, an example has been shown in which control information for device authentication, which is executed before the start of wireless power transmission, is transmitted and received using the second communication unit 207 of RX and the second communication unit 307 of TX. However, the control information transmitted and received by the above control is not limited to information used for device authentication, and can be applied to the transmission and reception of various types of control information.

[0084] (Other embodiments) The present invention 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.

[0085] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0086] 101: power receiving device, 102: power transmitting device, 201: control unit, 206: first communication unit, 207: second communication unit

Claims

1. A power receiving device, power receiving means for wirelessly receiving power from a power transmitting device; a communication means for communicating with the power transmitting device, The communication means is transmitting identification information of the power receiving device to the power transmitting device at a first frequency; After transmitting the identification information, a request to perform communication at the first frequency to the power transmitting device at a second frequency higher than the first frequency is transmitted; After transmitting the request, communication regarding authentication processing is performed with respect to the power transmitting device at the second frequency; The power receiving device further comprises means for performing negotiation processing regarding power to be received from the power transmitting device after the authentication processing.

2. The power receiving device according to claim 1 , wherein the communication means receives, from the power transmitting device, information indicating whether authentication processing is possible at the second frequency.

3. The power receiving device according to claim 1 , wherein the communication unit transmits a request for information about an electronic certificate to the power transmitting device.

4. The power receiving device according to claim 3 , wherein the communication unit receives the information about the electronic certificate from the power transmitting device after transmitting a request for the information about the electronic certificate.

5. A method performed by a power receiving device, Receives power wirelessly from the power transmission device, transmitting identification information of the power receiving device to the power transmitting device at a first frequency; After transmitting the identification information, a request to perform communication at the first frequency to the power transmitting device at a second frequency higher than the first frequency is transmitted; After transmitting the request, communication regarding authentication processing is performed with respect to the power transmitting device at the second frequency; The method further comprises, after the authentication process, performing a negotiation process regarding power to be received from the power transmitting device.

Images