Power receiving device and method

Abstract

To provide a technique for performing device authentication using appropriate communication.SOLUTION: A power receiving device (101) has a first communication unit (206) that communicates with a power transmitting device (102) and a second communication unit (207) that performs communication at a higher speed than the first communication unit (206). The power receiving device (102) determines whether or not the power transmitting device has a function of performing device authentication via the second communication unit (207) by communication via the first communication unit (206) (S501). When it is determined that the power transmitting device has the above function and the second communication unit (207) is in an invalid state (S502, NO), the second communication unit (207) is valid (S505) and the device authentication via the second communication unit (207) is executed (S506).SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Technical development of wireless power transmission systems has been widely conducted. Patent Document 1 discloses a power transmission device and a power receiving device that comply with the standard (WPC standard) established by the Wireless Power Consortium (WPC), a standardization organization for wireless charging standards. The power transmission device and the power receiving device of Patent Document 1 exchange control information required for controlling power transmission by so-called in-band communication in which the control information is superimposed on the power to be transmitted and received. Patent Document 2 discloses a device authentication method between a power transmission device and a power receiving device that perform wireless charging. According to Patent Document 2, the power transmission device transmits challenge data to the power receiving device via a power transmission coil, and the power receiving device transmits response data created by performing authentication calculations on the challenge data to the power transmission device via a power receiving coil. The power transmission device then executes a device authentication protocol by collating the response data received from the power receiving device. Patent Document 3 further proposes a technology in which a control signal transmitted and received between the power transmission device and the power receiving device is transmitted via a frequency or coil (or antenna) different from that of wireless power transmission (so-called out-band communication). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-007116 A [Patent Document 2] JP 2010-104097 A [Patent Document 3] JP 2012-217224 A Summary of the Invention [Problem to be solved by the invention]

[0004] Since the communication for device authentication involves a large amount of data, it is preferable to perform the communication by out-band communication, which allows faster communication than in-band communication. However, even if the 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, the device authentication is performed using in-band communication, so it takes a long time to complete the device authentication.

[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 aspect of the present invention has the following configuration. A 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 includes: transmitting identification information of the power receiving device to the power transmitting device at a first frequency; Information indicating whether authentication is possible at the second frequency is received from the power transmitting device.

[0007] A power transmitting device according to another aspect of the present invention has the following configuration. A power transmitting means for wirelessly transmitting power to a power receiving device; A communication means for communicating with the power receiving device, The communication means includes: receiving, at a first frequency, an identification of the power receiving device from the power receiving device; Information indicating whether authentication is possible at the second frequency is transmitted to the power receiving device. Effect of the Invention

[0008] According to the present invention, device authentication can be performed using appropriate communication. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a wireless power transmission system according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a configuration example of a power receiving device according to an embodiment. [Diagram 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. [Diagram 5] 10 is a flowchart showing an example of the flow of a process for determining the start of BLE communication. [Figure 6] 10 is a flowchart showing an example of a processing flow of a power transmitting device. [Figure 7] 1A is a diagram showing the communication sequence for device authentication, FIG. 1B is a diagram showing the communication sequence for the I&C phase, and FIG. 1C is a diagram showing the communication sequence for the Negotiation phase. [Figure 8] FIG. 1 shows an example of the configuration of a Power Transmitter Capability Packet. [Figure 9] FIG. 1A is a diagram showing an example of a display for inquiring about permission for BLE ON, and FIG. 1B is a diagram showing an example of a display for pre-setting permission for BLE ON. [Figure 10] 4 is a diagram showing a first processing example executed in the wireless power transmission system according to the embodiment; [Figure 11] 6 is a diagram showing a second processing example executed in the wireless power transmission system according to the embodiment. [Figure 12] 11 is a diagram showing a third processing example executed in the wireless power transmission system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] (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 by 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 RX, and the power transmitting device 102 may be referred to as TX.

[0012] 104 is a range in which RX can receive power from TX. Note that RX and TX may have a function of executing 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 a hard disk device or a memory device, or may be information processing devices such as a personal computer (PC). In addition, RX and TX may be image input devices such as an imaging device (camera, video camera, etc.) or a scanner, or may be image output devices such as a printer, copier, projector, etc.

[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, wireless power transmission for wireless charging based on the WPC standard is performed between a power receiving coil of RX and a power transmitting coil of TX. Note that the method of wireless power transmission (wireless power transmission method) is not limited to the method defined by the WPC standard, and may be another method using an electromagnetic induction method, a magnetic field resonance method, an electric field resonance method, a microwave method, a laser, or the like. In addition, in this embodiment, wireless power transmission is used for wireless charging, but wireless power transmission may be performed for purposes other than wireless charging.

[0014] In the WPC standard, the amount of power guaranteed when RX receives power from TX is stipulated by a value called Guaranteed Power (hereafter referred to as "GP"). GP indicates the power value guaranteed to be output to the load of RX (e.g., a charging circuit, etc.) even if the positional relationship between RX and TX changes and the power transmission efficiency between the receiving coil and the transmitting coil decreases. For example, if GP is 5 watts, TX transmits power by controlling so that it can output 5 watts to the load in RX, even if the positional relationship between the receiving coil and the transmitting coil changes and the power transmission efficiency decreases.

[0015] 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.

[0016] First, communication for power transmission and reception control based on the WPC standard will be described. 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 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. In the following, the identification and configuration phase will be referred to as the I&C phase.

[0017] In the Selection phase, TX transmits Analog Pings intermittently to detect the presence of an object within the power transmission range (for example, RX or a conductor piece is placed on the charging stand 103). In the Ping phase, TX transmits Digital Pings and recognizes that the detected object is RX by receiving a response from RX that has received the Digital Ping. In the I&C phase, RX notifies TX of its identification information and capability information. In the Negotiation phase, the GP value is determined based on the GP value requested by RX and the power transmission capability of TX. In the Calibration phase, RX notifies TX of the received power value based on the WPC standard, and TX performs adjustments to transmit power efficiently. In the Power Transfer phase, which performs wireless power transmission, control is performed to continue power transmission and to stop power transmission due to an error or full charge.

[0018] The TX and RX communicate for controlling power transmission and reception by 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 almost the same as the range in which power can be transmitted. Therefore, the range 104 in FIG. 1 represents the range in which wireless power transmission and in-band communication are possible using the power transmission and reception coils of the TX and RX. In the following description, the expression "placed" on the RX means that the RX has entered inside the range 104, and also includes a state in which the RX is not actually placed on the charging stand 103.

[0019] 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 above-mentioned negotiation phase based on the result of the device authentication. For example, the RX requests the GP to be 15 watts for the TX that has been successfully authenticated, and requests the GP to be 5 watts for the TX that has not been successfully authenticated.

[0020] The GP when the equipment authentication is successful and when it is not is not limited to the combination of 15 watts and 5 watts. Any value may be used as long as the GP with the TX where the equipment authentication is successful is larger than the GP when the equipment authentication is not successful. In other words, the RX transmits and receives power at a larger GP only with the TX where the equipment authentication is successful. In this way, by determining the GP based on the result of the equipment authentication, the RX can receive power at a larger GP only from the TX that has passed a predetermined test defined in the WPC standard and is recognized as being capable of transmitting power at a larger GP.

[0021] In this embodiment, RX and TX perform communication for device authentication using either out-of-band communication, which uses an antenna and frequency different from those for wireless power transmission, or in-band communication, which uses the same antenna (coil) as for wireless power transmission and superimposes a signal. Here, out-of-band communication is capable of faster communication than in-band communication. If TX is capable of out-of-band communication, RX performs communication for device authentication using out-of-band communication, otherwise performs communication for device authentication using in-band communication. This process will be described later.

[0022] As an example of outband communication, in this embodiment, a communication method conforming to the Bluetooth (registered trademark) Low Energy (hereinafter referred to as "BLE") standard is used. In addition, it is assumed that the TX operates in the role of a BLE peripheral and the RX operates in the role of a BLE central, but these BLE roles may be reversed. In addition, the communication method of the outband communication is not limited to BLE. For example, the outband communication may be performed by a communication method such as a wireless LAN (e.g., Wi-Fi (registered trademark)) of the IEEE802.11 standard series, ZigBee, or NFC (Near Field Communication). It is assumed that when the TX is capable of outband communication and the RX is present in the range 104, the RX and the TX can exchange information by outband communication.

[0023] (2) Equipment configuration Next, the configuration of the power receiving device 101 (RX) and the power transmitting device 102 (TX) according to this embodiment will be described. Note that the configuration described below is merely an example, and a part (or in some cases, the whole) of the configuration described may be replaced with another configuration performing a similar function or may be omitted, and further configuration may be added to the configuration described. 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 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.

[0025] 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 later. In one example, the control unit 201 performs control necessary for device authentication and power reception in the RX. The control unit 201 may 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 include hardware dedicated to a specific process, such as an application specific integrated circuit (ASIC), or an array circuit, such as an FPGA (Field Programmable Gate Array) compiled to execute a predetermined process. The control unit 201 stores information to be stored during the execution of various processes in the memory 210. The control unit 201 may also measure time using a timer 211.

[0026] The battery 202 supplies the entire RX with power required for control, power reception, and communication, for example. The battery 202 also stores the 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. Then, the power receiving unit 203 converts the AC power into a direct current or an AC power of a predetermined frequency, and supplies the power to each unit of the RX including the charging unit 212. The charging unit 212 performs processing for charging 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.

[0027] The detection unit 204 detects whether or not the RX is placed in the range 104 where 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 in the range 104 when, for example, the voltage when the Digital Ping is received is below a predetermined voltage threshold or the current value exceeds a predetermined current threshold.

[0028] The first communication unit 206 performs control communication based on the WPC standard as described above with the TX through in-band communication. The first communication unit 206 demodulates the electromagnetic waves input from the power receiving coil 205 to obtain information transmitted from the TX, and performs communication with the TX by superimposing information to be transmitted to the TX on the electromagnetic waves through load modulation of the electromagnetic waves. That is, the communication performed by the first communication unit 206 is performed by being superimposed on the power transmission from the power transmitting coil 305 of the TX.

[0029] The second communication unit 207 performs communication for device authentication with the TX through out-band communication. In addition, the second communication unit 207 may perform communication other than the communication for device authentication. The second communication unit 207 has a modulation / demodulation circuit and a communication protocol processing function required for communication conforming to the BLE standard, for example.

[0030] The display unit 208 presents information to the user by any method such as visual, auditory, or tactile. The display unit 208 notifies the user of, for example, the state of RX or the state of the wireless power transmission system including TX and RX as shown in FIG. 1. The display unit 208 includes, for example, a liquid crystal display, an LED, a speaker, a vibration generating circuit, and 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, a keyboard, or a microphone, a motion detection device such as an acceleration sensor or a gyro sensor, or other input devices. Note that 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. Note that the memory 210 may store information obtained by a functional unit different from the control unit 201. The timer 211 measures time, for example, by 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.

[0031] 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.

[0032] 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 later. In one example, the control unit 301 performs device authentication in the TX and control required for power transmission. The control unit 301 may 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 include hardware dedicated to a specific process, such as an application specific integrated circuit (ASIC), or an array circuit, such as an FPGA (Field Programmable Gate Array) compiled to execute a specific process. The control unit 301 stores information to be stored during the execution of various processes in the memory 310. The control unit 301 may also measure time using a timer 311.

[0033] The power supply unit 302 supplies power (DC or AC power) required for control, power transmission, and communication to the entire TX. The power supply unit 302 is, for example, a commercial power source or a battery.

[0034] The power transmitting unit 303 converts the 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 receiving power at the RX. The frequency of the AC power generated by the power transmitting unit 303 is about several hundred kHz (for example, 110 kHz to 205 kHz), which is different from the communication frequency (2.4 GHz) of BLE used in out-band communication. Based on an instruction 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 (power transmitting voltage) or current (power transmitting current) input to the power transmitting coil 305. Increasing the power transmitting voltage or power transmitting current increases the intensity of the electromagnetic waves, and decreasing the power transmitting voltage or power transmitting current decreases the intensity of the electromagnetic waves. Furthermore, based on an instruction from the control unit 301, the power transmitting unit 303 performs output control of AC power so that power transmission from the power transmitting coil 305 is started or stopped.

[0035] The detection unit 304 detects whether an object is 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 through 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 this object is an RX or another foreign object is determined based on whether a predetermined response is received in response to a Digital Ping transmitted by the first communication unit 306 in in-band communication. When a predetermined response is received in response to a Digital Ping, it is determined that an RX is present.

[0036] 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 obtain information transmitted by the RX. In this way, the communication performed by the first communication unit 306 is superimposed on the power transmission from the power transmitting coil 305.

[0037] The second communication unit 307 performs communication for device authentication with the RX by out-band communication. In addition, the second communication unit 307 may perform communication other than the communication for device authentication. The second communication unit 307 has a modulation / demodulation circuit and a communication protocol processing function required for communication conforming to the BLE standard, for example.

[0038] The display unit 308 presents information to the user by any method such as visual, auditory, or tactile. The display unit 308 notifies the user of, for example, the state of TX or information indicating the state of the wireless power transmission system including TX and RX as shown in FIG. 1. The display unit 308 includes, for example, a liquid crystal display, an LED, a speaker, a vibration generating circuit, and other notification devices. The operation unit 309 has a function of accepting an operation for TX from the user. The operation unit 309 includes, for example, a voice input device such as a button, a keyboard, or a microphone, a motion detection device such as an acceleration sensor or a gyro sensor, or other input devices. Note that 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. Note that the memory 310 may store information obtained by a functional unit different from the control unit 301. The timer 311 measures time using, for example, a count-up timer that measures the elapsed time from the time when it was started, or a count-down timer that counts down from a set time.

[0039] (3) Processing flow Next, an example of the flow of processes executed by the RX and TX will be described.

[0040] [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 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 realizing each processing step. This processing can be executed in response to the RX being started by power supply from the battery 202 or the TX in response to the power supply of the RX being turned on, or in response to the user of the RX inputting an instruction to start a wireless charging application. This processing can also be started by another trigger.

[0041] After starting the process, the RX executes the process 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 by in-band communication in the I&C phase defined by the WPC standard (S402).

[0042] FIG. 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, as the identification information for each individual RX, a Manufacturer Code and a Basic Device ID, as well as information elements capable of identifying the version of the WPC standard supported by the RX as capability information. The RX further transmits a Configuration Packet to the TX (F712). The Configuration Packet includes, as capability information for the RX, a Maximum Power Value, which is a value specifying the maximum power that the RX can supply to a load, and information indicating whether or not the RX has a negotiation function of the WPC standard. Here, the RX includes, in the capability information, information indicating that BLE communication is possible (BLE communication possible information). In this way, the BLE communication possible information is transmitted by the Configuration Packet as part of the capability information. Note that the communication possible information may be transmitted by being included in the ID Packet or another packet. When the TX receives these packets, it transmits an ACK (F713), and the I&C phase ends.

[0043] The RX may notify the TX of its identification information and capability information by a method other than the communication in the I&C phase of the WPC standard. Any other identification information capable of identifying an individual RX may be used as the identification information for each 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. The capability information may include information other than the above.

[0044] Returning to Fig. 4, after S402, RX acquires capability information from TX through in-band communication (S403). The capability information of 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, capability information from TX may be acquired by other packets. In the following description, it is assumed that the TX Capability Packet is used as capability information acquired from TX.

[0045] When the RX acquires the capability information from the TX, the RX performs a BLE communication start determination process (S404). The details of the BLE communication start determination process will be described later. When it is determined that the BLE communication is to 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 source (S406). Note that in S403, the BD_ADDR may be acquired from the TX by in-band communication, and in S406, the BLE connection may be established by directly transmitting a CONNECT_REQ to the BD_ADDR without waiting for the advertising packet. Next, the RX communicates with the TX for device authentication by the BLE communication established above (S407).

[0046] Here, the contents of communication for device authentication between RX and TX will be described with reference to Fig. 7(A). In this embodiment, device authentication is a challenge-response type device authentication using an electronic certificate, and RX authenticates TX. TX may authenticate RX, or each may authenticate the other. RX acts as an initiator that transmits a challenge text to TX, and TX acts as a responder that encrypts the challenge text received from RX and transmits it to RX.

[0047] First, RX transmits a GET_DIGESTS message to TX (F701). GET_DIGESTS is a message requesting information about the digital certificate held by the receiver (TX). In response to GET_DIGESTS, TX transmits DIGESTS to RX (F702). DIGESTS is information about the digital certificate held by the sender (TX). Next, RX transmits a GET_CERTIFICATE message requesting detailed information (CERTIFICATE) about the digital certificate to TX (F703). In response to the GET_CERTIFICATE from RX, TX transmits CERTIFICATE to RX (F704). Then, RX transmits a CHALLENGE message including a challenge text to TX (F705), and TX transmits a RESPONSE obtained by encrypting the challenge text received from RX to RX (F706).

[0048] When the validity of the RESPONSE received from the TX is confirmed, the RX transmits RESULT(Success) to the TX (F707) and ends the equipment authentication. RESULT(Success) means that the validity of the RESPONSE can be confirmed and the equipment authentication is successful. If the equipment authentication fails, RESULT(Fail) is transmitted instead of RESULT(Success), and the equipment authentication process ends. If the initiator (RX) receives a message indicating that the other device (TX) does not support equipment authentication communication, it determines that the other device does not support equipment authentication. If the initiator (RX) does not receive a response during communication, it may retry by resending a message to obtain the response, or may determine that the other device does not support equipment authentication. The RX may not communicate for equipment authentication with the TX that does not support equipment authentication, and may not determine that the result of the equipment authentication is successful.

[0049] Each of the above messages is transmitted and received by any of Read, Write, Notify, and Indicate of the characteristic of the predefined GATT service in GATT communication in the BLE connection. GATT communication is performed by transmitting and receiving packets standardized in BLE. When the communication for device authentication is completed, the RX disconnects the BLE connection by transmitting LL_TERMINATE_IND of BLE. The BLE connection may be disconnected from the TX. When 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, the RX may obtain information on whether or not the TX supports device authentication in a BLE advertising packet or GATT communication prior to the communication for device authentication. If the TX does not support device authentication, the RX may determine that the TX does not support device authentication and may not execute the communication of FIG. 7(A).

[0050] 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 transmitted and received between TX and RX as an in-band communication packet.

[0051] After performing communication for device authentication by BLE or in-band communication (S407, S408), RX performs negotiation with TX based on the result of device authentication (S409). If device authentication is successful (YES in S409), RX performs negotiation to set GP to 15 watts (S410), otherwise (NO in S409), RX performs negotiation to set GP to 5 watts (S411).

[0052] 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 the equipment 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 it is accepted, or NAK if it is not accepted to RX (F722).

[0053] Here, if the size of the GP requested by RX is a size that can be transmitted by the power transmission capability of the own device, TX accepts the request of RX. At this time, the value of GP is determined to be the same as the value requested by RX. On the other hand, if the size of the GP requested by RX is a size that cannot be achieved by the power transmission capability of the own device, TX does not accept the request of RX. In this case, for example, a small value predefined in the WPC standard may be determined as the value of GP. Note that a small value other than the value predefined in the WPC standard may be determined as the value of GP at this time. In one example, these small values ​​are stored in advance in the memory 210 of RX and the memory 310 of TX.

[0054] In addition, when TX can transmit power to multiple RXs simultaneously and is already transmitting power to another RX, TX may determine the value of GP based on the current transmission margin instead of its own power transmission capability. In addition, in S410 and S411, communication in the negotiation phase of the WPC standard is used, but this is not limited to this, and other procedures for determining GP based on the result of device authentication between TX and RX may be executed. In addition, when TX acquires information indicating that RX does not support the negotiation phase (for example, in S402), TX may not perform communication in the negotiation phase and may set the value of GP to a small value (for example, predefined in the WPC standard).

[0055] 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 of the power transmitted from the TX to the RX measured inside the TX and the value of the received power measured inside the RX. The TX performs this process by processing in the Calibration phase of the WPC standard. Furthermore, receiving power until full charge is performed by 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, the calibration and power reception may be performed by a method other than the WPC standard.

[0056] When the RX reaches full charge in the Power Transfer phase, it transmits an End Power Transfer of the WPC standard. This stops the power transmission from the TX, and the series of processes for wireless charging ends. After the series of processes for wireless charging ends, if the BLE was OFF when the RX was placed on the TX (YES in S414), the RX turns off the BLE (S415) and ends this process. If the BLE connection is used by another application, it is not necessary to turn off the BLE. On the other hand, if the BLE is ON (NO in S414), nothing is done and this process ends. After this, the RX may return to S401, or may return to S401 after waiting for another trigger, such as when the remaining battery level drops below a predetermined level.

[0057] 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 realizing each processing step. Also, this process can be executed in response to receiving capability information from the TX, but may be started by another trigger.

[0058] The RX checks whether the capability information acquired from the TX in S403 includes information indicating that device authentication by BLE communication is possible (S501). Whether or not the capability information includes information indicating that device authentication by BLE communication is possible can be determined by, for example, checking a bit indicating the capability of device authentication using out-band communication included in the capability information, a bit indicating the retention of BLE, a bit indicating whether BLE is available, etc. If the capability information acquired from the TX includes information indicating that device authentication by BLE communication is possible (YES in S501), the RX determines whether or not its own BLE is ON (whether or not the BLE status is valid) (S502). On the other hand, if the capability information acquired from the TX does not include information indicating that device authentication by BLE communication is possible (NO in S501), the RX ends this process without doing anything.

[0059] If BLE is enabled (ON) (YES in S502), RX determines whether or not 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, RX determines that BLE communication is impossible. Also, if the remaining charge of the battery 202 is low, RX may determine that BLE communication is impossible. If BLE communication is possible (YES in S503), RX transmits a BLE communication start request to TX (S506) and ends this process. 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 may be made by another packet. On the other hand, if BLE communication is impossible (NO in S503), this process ends without doing anything.

[0060] When BLE is disabled (BLE is not ON) (NO in S502), the RX judges whether or not turning on BLE is permitted by the user (S504). The user permits turning on BLE by, for example, displaying an inquiry 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 selecting an area 901 instructing permission. On the other hand, disallowing enabling BLE (turning on BLE) is performed by the user selecting an area 902 instructing disallowance in the inquiry 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 it is permitted without displaying the inquiry display 900.

[0061] 9B, 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 having the user activate 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.

[0062] If BLE is permitted to be enabled (YES in S504), BLE is enabled (ON) (S505), and then a BLE communication start request is sent to the TX (S506), and this process ends. On the other hand, if BLE is not permitted to be enabled (NO in S504), this process ends without doing anything.

[0063] [3.2] Processing in the power transmission device Next, an example of the flow of the process executed by the TX will be described with reference to FIG. 6. This process 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 may 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 realizing each processing step. This process can be executed in response to the power supply of the TX being turned on, in response to the user of the TX inputting an instruction to start a wireless charging application, or in response to the TX being connected to a commercial power source and receiving power supply. This process may also be started by another trigger.

[0064] 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 Ping of the WPC standard to detect an object that exists within the power transmission range (Selection phase). Then, when the TX detects that an object exists within the power transmission range, it transmits Digital Ping. When 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).

[0065] When TX detects that RX is placed, it executes the above-mentioned I&C phase communication by in-band communication and acquires identification information and capability information from the RX (S602). Then, it waits to receive a capability information acquisition request from the RX (S603). If it receives a capability information acquisition request (YES in S603), it transmits capability information (S604), but if it cannot receive it (NO in S603), it does nothing and waits to receive a BLE communication start request from the RX (S605).

[0066] In this embodiment, one bit of the reserved area of ​​the TX Capability Packet in FIG. 8, from bit 6 to bit 7 (800) of Bank1 or bit 2 to bit 7 (801) of Bank2, is assigned as the Auth bit. The Auth bit is an example of capability information. If the TX has the capability to perform 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 of the reserved area. If the TX has the capability to use BLE for outband communication, or if the TX has a 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 of 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.

[0067] Returning to FIG. 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 in its own device (S606). Next, the TX performs communication for device authentication with the RX described in FIG. 7(A) through the BLE connection established in S606 (S607). On the other hand, when the BLE communication start request cannot be received from the RX in S605 (NO in S605), it performs communication for device authentication described in FIG. 7(A) using in-band communication (S608). After that, the TX performs negotiation with the RX as shown in FIG. 7(C) and determines the GP (S609). After determining the GP, the TX performs calibration (S610) and power transmission until full charge based on the GP (S611).

[0068] In addition, when TX receives an End Power Transfer of the WPC standard from RX, it ends the process in any processing phase according to the WPC standard, stops power transmission, and returns to the Selection phase of S601. Note that even if the battery is fully charged, End Power Transfer is sent from RX, so the process returns to the Selection phase of S601.

[0069] [3.3] System operation The operation sequence 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.

[0070] <Processing example 1> First, processing example 1 will be described with reference to Fig. 10. In processing example 1, TX is a device that holds the second communication unit 307, i.e., the function of outband communication by BLE, is in a state in which BLE communication is possible, and succeeds in device authentication of RX. In addition, 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 permit BLE ON.

[0071] First, TX waits for an object to be placed by 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). The following Digital Ping causes RX to detect that it has been placed on TX (S401, F1005, F1006). The TX also detects that the object placed is RX by the response to Digital Ping. Next, RX notifies RX that BLE communication is possible by communication in the I&C phase (S402, S602, F1007). Next, RX sends a capability information acquisition request (S403, F1008), and TX sends capability information (YES in S603, S604, F1009).

[0072] When RX receives the capability information from TX, it starts the BLE communication start determination process (S404). Since the capability information of TX includes information that device authentication by BLE communication is possible, RX checks whether its own BLE is ON (YES in S501, S502). Since its own BLE is OFF and BLE ON has not been permitted in advance, RX displays 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 transmits a BLE communication start request to TX (S506, F1012). When TX receives a BLE communication start request, TX transmits a BLE advertising packet (F1013), and RX transmits CONNECT_REQ (F1014), and a BLE connection is established (YES in S405, S406, YES in S605, S606).

[0073] Next, communication for device authentication via BLE is performed, and device authentication is successful (S407, S607, F1015). Because device authentication is successful, GP = 15 watts is determined by negotiation between RX and TX (YES in S409, S410, S608, F1016). After that, calibration is performed (S412, S609, F1017) and power is transmitted and received until the battery is fully charged (S413, S610, F1018). When the battery is fully charged, an End Power Transfer is sent from RX and the process ends (F1019).

[0074] According to the operation described above, when RX is placed on a TX capable of outband communication via BLE with its own BLE in the OFF state, it turns BLE on to perform communication for equipment authentication, and can receive power based on the result of the equipment authentication.

[0075] <Processing example 2> Next, processing example 2 will be described with reference to Fig. 11. In processing example 2, 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 given permission to turn BLE ON in advance. The following description will focus on the differences from Fig. 10.

[0076] In FIG. 11, the process from detection of placement to transmission of capability information by TX (F1101 to F1109) is the same as FIG. 10 (F1001 to F1009). When RX receives capability information from TX, it starts BLE communication start determination processing (S404). Since RX has been permitted to turn on BLE by the user in advance, RX automatically turns on BLE without inquiring whether to permit turning on BLE (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 RX is placed on a TX capable of out-band communication by BLE, RX automatically turns on BLE without making the user aware of the BLE state, performs communication for device authentication, and is able to receive power based on the result.

[0077] <Processing example 3> Next, processing example 3 will be described with reference to 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 BLE ON has not been permitted in advance by the user, and there is no user operation in response to an inquiry as to whether BLE ON is permitted, so ON is not permitted. The following description will focus on the differences from Fig. 10.

[0078] In Fig. 12, the process from detection of placement to the inquiry display of whether or not to permit BLE to be turned on (F1201 to F1210) is the same as in 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 BLE is not permitted to be turned on (NO in S504, F1211). Since RX is not permitted to permit BLE to be turned on, communication for device authentication is performed by in-band communication and is successful (NO in S405, S408, F1212). The subsequent operations (F1213 to F1216) until full charging are the same as in Fig. 10 (F1016 to F1019).

[0079] According to the operation described above, when RX is placed on TX capable of out-band communication using BLE, if the user does not permit 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 of the communication.

[0080] As described in the above processing examples 1 to 3, even if the RX according to this embodiment is placed on a TX that is capable of outband communication by BLE with BLE OFF, it can turn on BLE and perform communication for device authentication by outband communication. Here, since outband communication can be performed faster than inband communication, the time required for communication for device authentication is shorter when outband communication is used. Therefore, the time from when the RX is placed to when charging starts can be shortened. Also, even if the user does not permit BLE to be turned on, communication for device authentication can be performed by inband communication, so charging can be started without being affected by the state of BLE.

[0081] In this embodiment, if there is no user operation for a certain period of time in response to an inquiry about whether or not to permit 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 may not be terminated. In addition, 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, and BLE may be turned on to switch to device authentication using out-band communication. This reduces the time required for communication for device authentication compared to continuing device authentication using in-band communication, and the time until charging can be reduced. On the other hand, when the processing phase of device authentication performed on in-band communication is in progress, 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 lengthened 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 terminated.

[0082] In this embodiment, the case where device authentication is applied as a function using out-band communication has been described, but other functions that can be executed using out-band communication may be applied. For example, firmware update of the TX may be applied. In this case, the TX assigns one bit from bit 6 to bit 7 (800) of Bank1, which is a reserved area of ​​the TX Capability Packet, or bit 2 to bit 7 (801) of Bank2 to the Firmware Update bit. If the TX has the ability to perform firmware update using out-band communication, it writes "1" to the Firmware Update bit, and if not, it writes "0". In this way, by applying it to a function that requires communication with a large amount of data, the time required for communication for the function can be greatly reduced.

[0083] In this embodiment, the BLE communication method is used as the outband communication. However, the RX may have a function of communicating using a plurality of communication methods, and any of these may be used as the outband communication. In that case, the capability information transmitted and received in S402 and S403 in FIG. 4 may include information on whether the BLE communication is possible, as well as information on whether the other communication methods are possible. In addition, in the BLE communication start determination process (S501 to S506) in FIG. 5, control may be performed such that the communication of the other communication methods is turned ON when it is OFF, according to the received capability information. As a result, for example, whether the device 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.

[0084] In the above embodiment, an example has been shown in which control information for device authentication executed before starting 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-mentioned control is not limited to information used for device authentication, and can be applied to transmission and reception of various types of control information.

[0085] (Other embodiments) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0086] The invention is not limited to the above-described embodiments, and various modifications and variations are possible 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]

[0087] 101: power receiving device, 102: power transmitting device, 201: control unit, 206: first communication unit, 207: second communication unit

Claims

[Claim 1] A power receiving device, A 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 includes: Transmitting identification information of the power receiving device to the power transmitting device at a first frequency; The power receiving device receives, from the power transmitting device, information indicating whether authentication is possible at the second frequency.

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