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

[0003]

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

Background Art

[0002] The technological development of wireless power transmission systems has been widely carried out. In Patent Document 1, a power transmission device and a power receiving device compliant with the standard (WPC standard) established by the wireless charging standardization organization Wireless Power Consortium (WPC) are disclosed. The power transmission device and the power receiving device in Patent Document 1 exchange control information necessary for power transmission control by so-called in-band communication that superimposes the control information on the power to be transmitted and received. Further, Patent Document 2 discloses a device authentication method between a power transmission device and a power receiving device that performs wireless charging. According to Patent Document 2, the power transmission device transmits challenge data to the power receiving device via the power transmission coil, and the power receiving device transmits response data created by performing an authentication operation on the challenge data to the power transmission device via the power receiving coil. Then, the device authentication protocol is executed by collating the response data received by the power transmission device from the power receiving device. Furthermore, in Patent Document 3, a technique is proposed in which control signals transmitted and received between a power transmission device and a power receiving device are transmitted by communication (so-called out-of-band communication) using a frequency or coil (or antenna) different from that of wireless power transmission.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0005] This invention provides a technology 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 comprises a power receiving means for receiving power wirelessly from a power transmitting device, 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 with the power transmitting device at the second frequency regarding authentication processing, and 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. [Effects of the Invention]

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

[0008] [Figure 1] A diagram showing the configuration of a wireless power transmission system according to an embodiment. [Figure 2] A block diagram showing an example configuration of a power receiving device according to an embodiment. [Figure 3] A block diagram showing an example configuration of a power transmission device according to an embodiment. [Figure 4]A flowchart illustrating an example of the processing flow of a power receiving device. [Figure 5] A flowchart illustrating an example of the process for determining whether BLE communication should start. [Figure 6] A flowchart illustrating an example of the processing flow in a power transmission system. [Figure 7] (A) is a diagram showing the communication sequence for device authentication, (B) is a diagram showing the communication sequence for the I&C phase, and (C) is a diagram showing the communication sequence for the Negotiation phase. [Figure 8] A diagram showing an example configuration of a Power Transmitter Capability Packet. [Figure 9] (A) is a diagram showing an example of a display for querying permission to turn BLE ON, and (B) is a diagram showing an example of a display for pre-configuring permission to turn BLE ON. [Figure 10] A diagram showing a first example of processing performed in the wireless power transmission system of the embodiment. [Figure 11] A diagram showing a second example of processing performed in the wireless power transmission system of the embodiment. [Figure 12] A diagram showing a third example of processing performed in the wireless power transmission system of the embodiment. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention to the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] (1) System Configuration Figure 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 of this embodiment is configured to include 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 to the power receiving device 101 by wireless power transmission from the power transmitting device 102. The power receiving device 101 is an electronic device that receives power from the power transmitting device 102 and charges its built-in battery. The power transmitting device 102 is an electronic device that wirelessly transmits power to the RX placed on the charging base 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.

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

[0012] This system performs wireless power transmission using an electromagnetic induction method based on the WPC (Wireless Power Consortium) standard. Specifically, wireless power transmission for wireless charging is performed between the RX receiving coil and the TX transmitting coil based on the WPC standard. The wireless power transmission method is not limited to the method specified in the WPC standard, but may also be other methods such as electromagnetic induction, magnetic field resonance, field resonance, microwave, or laser. Furthermore, in this embodiment, wireless power transmission is used for wireless charging, but wireless power transmission may also be used for purposes other than wireless charging.

[0013] In the WPC standard, the amount of power guaranteed when the RX receives power from the TX is defined by a value called Guaranteed Power (hereinafter referred to as "GP"). GP indicates the power value that is guaranteed to be output to the load of the RX (for example, a circuit for charging, etc.) even if, for example, the positional relationship between the RX and the TX changes and the power transmission efficiency between the power receiving coil and the power transmitting coil decreases. For example, when GP is 5 watts, even if the positional relationship between the power receiving coil and the power transmitting coil changes and the power transmission efficiency decreases, the TX controls the power transmission so that it can output 5 watts to the load in the RX.

[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, the communication for power transmission and reception control based on the WPC standard will be described. In the WPC standard, a plurality of phases are defined, including a phase before actual power transmission and a Power Transfer phase in which power transmission is executed, and communication for the necessary power transmission control is performed in each phase. The phases before power transmission include the Selection phase, the Ping phase, the Identification and Configuration phase, the Negotiation phase, and the Calibration phase. Hereinafter, the Identification and Configuration phase will be referred to as the I&C phase.

[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, an RX or conductor piece being placed on the charging base 103). In the Ping phase, the TX transmits a Digital Ping and receives a response from the RX that received the Digital Ping, thereby recognizing that the detected object is an RX. In the I&C phase, the RX notifies the TX of its identification and capability information. In the Negotiation phase, the GP value is determined based on the GP value requested by the RX and the TX's power transmission capability. 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 efficiently transmit power. In the Power Transfer phase, which performs wireless power transmission, control is performed to continue power transmission and to stop power transmission due to errors or full charge.

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

[0018] In this embodiment, prior to determining the GP, the RX engages in challenge-response communication with the TX using an electronic certificate to authenticate the TX. That is, communication for device authentication takes place prior to determining the GP. Then, based on the results of the device authentication, the RX determines the GP to request from the TX in the Negotiation phase. For example, the RX requests a GP of 15 watts from a TX that has successfully been authenticated, and a GP of 5 watts from a TX that has not been authenticated.

[0019] Furthermore, the GP (Ground Power) for successful and unsuccessful equipment certification is not limited to a 15-watt and 5-watt combination. Any value may be used as long as the GP with a successfully certified TX (Transporter) is greater than the GP in unsuccessful cases. In other words, the RX (Receiving Terminal) will only transmit and receive power at a large GP with a successfully certified TX. By determining the GP based on the results of equipment certification in this way, the RX will only be able to receive power at a large GP from TXs that have passed the prescribed tests stipulated in the WPC standard, etc., and are deemed capable of transmitting power at a large GP.

[0020] In this embodiment, the RX and TX communicate for device authentication using either out-of-band communication, which uses a different antenna and frequency than that used for wireless power transmission, or in-band communication, which superimposes signals using the same antenna (coil) as wireless power transmission. Here, it is assumed that out-of-band communication is faster than in-band communication. If the TX is capable of out-of-band communication, the RX uses out-of-band communication to perform device authentication; otherwise, it uses in-band communication. This process will be described later.

[0021] As an example of outband communication, this embodiment uses a communication method compliant with the Bluetooth® Low Energy (hereinafter referred to as "BLE") standard. Furthermore, TX operates as the Peripheral of BLE, and RX operates as the Central of BLE; however, these BLE roles may be reversed. Also, the communication method for outband communication is not limited to BLE. For example, outband communication may be performed using communication methods such as IEEE 802.11 standard series wireless LAN (e.g., Wi-Fi®), ZigBee, or NFC (Near Field Communication). Note that when TX is capable of outband communication and RX is within range 104, RX and TX are assumed to be able to 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 configuration described below is merely an example, and some (or in some cases all) of the described configuration may be replaced or omitted by other configurations that perform similar functions, and further configurations may be added to the described configuration. Furthermore, one block shown in the following description may be divided into multiple blocks, or multiple blocks may be integrated into one block.

[0023] Figure 2 shows 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.

[0024] The control unit 201 controls the entire RX and performs various processes described later, for example, by executing a control program stored in the memory 210. In one example, the control unit 201 performs the 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 is configured to include one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 201 may also be configured to include hardware dedicated to specific processing, such as an application-specific integrated circuit (ASIC), or array circuits such as an FPGA (Field-Programmable Gate Array) compiled to execute predetermined processing. The control unit 201 stores information that should be stored while various processes are being executed in the memory 210. The control unit 201 can also measure time using a timer 211.

[0025] Battery 202 supplies power to the entire RX, for example, power necessary for control, power reception, and communication. 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 TX's power transmitting coil 305 (Figure 3). 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 DC or AC power of a predetermined frequency and supplies power to each part 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 GP mentioned above 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 located within the range 104 from which it can receive power from the TX, based on the WPC standard. For example, the detection unit 204 detects the voltage or current value of the receiving coil 205 when the power receiving unit 203 receives a Digital Ping according to the WPC standard via the receiving coil 205. For example, the detection unit 204 determines that the RX is located within the range 104 if the voltage when the Digital Ping is received falls below a predetermined voltage threshold or the current value exceeds a predetermined current threshold.

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

[0028] The second communication unit 207 communicates with the TX for device authentication via out-of-band communication. In addition, the second communication unit 207 may also perform communications other than those for device authentication. The second communication unit 207 has modulation / demodulation circuits and communication protocol processing functions necessary for performing communications compliant with standards such as BLE.

[0029] The display unit 208 presents information to the user by any method, such as visual, auditory, or tactile. For example, the display unit 208 notifies the user of the status of the RX and the status of the wireless power transmission system including the TX and RX as shown in Figure 1. The display unit 208 is composed of, for example, a liquid crystal display, LEDs, a speaker, a vibration generating circuit, and other notification devices. The operation unit 209 has the function of receiving operations on the RX from the user. The operation unit 209 is composed of, for example, buttons, a keyboard, an audio input device such as a microphone, a motion detection device such as an accelerometer or gyroscope, 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 different functional unit than 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.

[0030] Figure 3 is a block diagram showing an example 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 controls the entire TX and performs various processes described later, for example, by executing a control program stored in the memory 310. In one example, the control unit 301 performs device authentication and the 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 is configured to include one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 301 may also be configured to include hardware dedicated to specific processing, such as an application-specific integrated circuit (ASIC), or array circuits such as an FPGA (Field-Programmable Gate Array) compiled to execute predetermined processing. The control unit 301 stores information that should be stored while various processes are being executed in the memory 310. The control unit 301 can also measure time using a timer 311.

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

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

[0034] The detection unit 304 detects whether an object is present or placed within range 104 based on the WPC standard. For example, the detection unit 304 detects the voltage or current value of the power transmission coil 305 when the power transmission unit 303 transmits an Analog Ping according to the WPC standard via the power transmission coil 305. The detection unit 304 can then determine that an object is present within range 104 if the voltage falls 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 by whether or not a predetermined response is received to a Digital Ping transmitted via in-band communication by the first communication unit 306. If a predetermined response is received to the Digital Ping, it is determined that an RX is present.

[0035] The first communication unit 306 communicates with the RX via in-band communication, performing control communication based on the WPC standard as described above. The first communication unit 306 modulates the electromagnetic waves output from the power transmission coil 305 and transmits information to the RX. The first communication unit 306 also demodulates the electromagnetic waves output from the power transmission coil 305 and modulated at the RX to obtain the 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 transmission coil 305.

[0036] The second communication unit 307 communicates with the RX for device authentication via out-of-band communication. In addition, the second communication unit 307 may also perform communications other than those for device authentication. The second communication unit 307 has modulation / demodulation circuits and communication protocol processing functions necessary for performing communications that comply with standards such as BLE.

[0037] The display unit 308 presents information to the user by any method, such as visual, auditory, or tactile. For example, the display unit 308 notifies the user of information such as the status of TX or the status of a wireless power transmission system including TX and RX as shown in Figure 1. The display unit 308 is composed of, for example, a liquid crystal display, LEDs, a speaker, a vibration generating circuit, and other notification devices. The operation unit 309 has the function of receiving operations on TX from the user. The operation unit 309 is composed of, for example, buttons, a keyboard, an audio input device such as a microphone, a motion detection device such as an accelerometer or gyroscope, 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 different functional unit than the control unit 301. Timer 311 performs timing using, for example, a count-up timer that measures the elapsed time since the time of activation, or a count-down timer that counts down from a set time.

[0038] (3) Processing flow Next, we will explain an example of the processing flow performed by RX and TX.

[0039] [3.1] Processing in the power receiving device 101 (RX) Figure 4 is a flowchart illustrating an example of processing performed by the RX. This processing can be implemented, for example, by the RX's control unit 201 executing a program read from memory 210. At least part of the following procedure may be implemented by hardware. In this case, the hardware can be implemented, for example, by automatically generating a dedicated circuit using a gate array circuit such as an FPGA from a program to implement each processing step using a predetermined compiler. This processing can also be executed when the RX is powered on and the RX is started by power supplied from battery 202 or TX, or when the RX user inputs a command to start a wireless charging application. This processing may also be started by other triggers.

[0040] After processing begins, the RX performs the processes defined as the Selection and Ping phases of the WPC standard and waits for its device to be connected to the TX (S401). The RX detects that it has been connected to the TX, for example, by detecting a Digital Ping from the TX. Once the RX detects that it has been connected to the TX, it transmits identification information and capability information to the TX via in-band communication using the I&C phase communication defined in the WPC standard (S402).

[0041] Figure 7(B) shows the communication flow during the I&C phase. In the I&C phase, the RX sends an Identification Packet (ID Packet) to the TX (F711). The ID Packet contains the Manufacturer Code and Basic Device ID, which are individual identification information for each RX, as well as information elements that can identify the version of the WPC standard that the RX supports, as part of the RX's capability information. The RX then sends a Configuration Packet to the TX (F712). The Configuration Packet includes the Maximum Power Value, which is a value that identifies the maximum power that the RX can supply to the load, and information indicating whether or not it has the WPC standard's Negotiation function, as part of the RX's capability information. Here, the RX includes information indicating that BLE communication is possible (BLE communication enabled information) in the capability information. Thus, the BLE communication enabled information is transmitted as part of the capability information via the Configuration Packet. Note that the communication enabled information may also be transmitted included in the ID Packet or other packets. When the TX receives these packets, it sends an ACK (F713), and the I&C phase ends.

[0042] Furthermore, the RX may notify the TX of its identification information and capability information by means other than the I&C phase communication of the WPC standard. In addition, the identification information for each individual RX may include any other identification information that can identify the individual RX, such as the Wireless Power ID or the Bluetooth Address unique to the RX's second communication unit 207 (hereinafter referred to as "BD_ADDR"). The capability information may also include information other than that mentioned above.

[0043] Returning to Figure 4, after S402, the RX obtains capability information from the TX via in-band communication (S403). The TX's capability information can be obtained, for example, by the Power Transmitter Capability Packet of the WPC standard shown in Figure 8 (hereinafter referred to as the "TX Capability Packet"). Of course, capability information from the TX may also be obtained in other packets. From here on, the explanation will assume that the TX Capability Packet is used as the capability information obtained from the TX.

[0044] When the RX obtains capability information from the TX, it 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 sending CONNECT_REQ to the BD_ADDR of the source (S406). Alternatively, in S403, the RX may obtain the BD_ADDR from the TX via in-band communication, and in S406, without waiting for the advertising packet, directly send CONNECT_REQ to the BD_ADDR to establish a BLE connection. Subsequently, the RX communicates with the TX for device authentication using the BLE communication established above (S407).

[0045] Here, the content of the communication for device authentication between RX and TX will be explained using Figure 7(A). In this embodiment, device authentication is a challenge-response type device authentication using an electronic certificate, and RX authenticates TX. Alternatively, TX may authenticate RX, or both may authenticate each other. RX acts as an initiator, sending a challenge text to TX, and TX acts as a responder, encrypting the challenge text received from RX and sending it back to RX.

[0046] First, RX sends a GET_DIGESTS message to TX (F701). GET_DIGESTS is a message requesting information about the digital certificates held by its recipient (TX). In response to GET_DIGESTS, TX sends DIGESTS to RX (F702). DIGESTS is information about the digital certificates owned by its sender (TX). Next, RX sends a GET_CERTIFICATE message to TX requesting detailed information about the digital certificate (CERTIFICATE) (F703). In response to GET_CERTIFICATE from RX, TX sends CERTIFICATE to RX (F704). Then, RX sends a CHALLENGE message containing the challenge text to TX (F705), and TX sends a RESPONSE message to RX containing the encrypted challenge text received from RX (F706).

[0047] If the RX confirms the validity of the RESPONSE received from the TX, it sends RESULT(Success) to the TX (F707) and terminates device authentication. RESULT(Success) means that the validity of the RESPONSE has been confirmed and device authentication has been successful. If device authentication fails, RESULT(Fail) is sent instead of RESULT(Success), and the device authentication process terminates. If the initiator (RX) receives a message indicating that the remote device (TX) does not support device authentication communication, it determines that the remote 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 a response, or it may determine that the remote device does not support device authentication. The RX may choose not to communicate for device authentication with a TX that does not support device authentication, and may not consider the device authentication result to be successful.

[0048] The messages described above are sent and received in GATT communication over a BLE connection using one of the Read, Write, Notify, or Indicate characteristics of a predefined GATT service. GATT communication is performed by sending and receiving packets standardized by BLE. Once the communication for device authentication is complete, the RX disconnects the BLE connection by sending BLE's LL_TERMINATE_IND. Alternatively, the TX may disconnect the BLE connection. If the BLE connection is used by another application, the BLE connection may not be disconnected even after the device authentication communication is complete. Furthermore, prior to the communication for device authentication, the RX may obtain information in the BLE advertising packet or GATT communication regarding whether the TX supports device authentication. If the TX does not support device authentication, the RX may determine that it does not support device authentication and may not execute the communication shown in Figure 7(A).

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

[0050] After performing device authentication communication via BLE or in-band communication (S407, S408), RX negotiates with TX based on the results of device authentication (S409). If device authentication is successful (YES in S409), RX negotiates to set the GP to 15 watts (S410); otherwise (NO in S409), RX negotiates to set the GP to 5 watts (S411).

[0051] During negotiation, communication in the Negotiation phase of the WPC standard takes place, as shown in Figure 7(C). First, the RX notifies the TX of the requested GP value by sending a Specific Request (F721). That is, if the device authentication is successful, it notifies GP=15 watts, and otherwise it notifies GP=5 watts. The TX determines whether to accept the request based on the power transmission capacity of its device, and sends an ACK to the RX if it accepts, or a NAK if it does not (F722).

[0052] Here, TX accepts RX's request if the requested GP size is within the power transmission capacity of its own device. In this case, the GP value is determined to be the same as the value requested by RX. On the other hand, TX does not accept RX's request if the requested GP size is beyond the power transmission capacity of its own device. In this case, for example, a small value predetermined by the WPC standard may be determined as the GP value. Note that a small value other than the value predetermined by 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 memory 210 of RX and the memory 310 of TX.

[0053] Furthermore, if the TX is capable of simultaneously supplying power to multiple RXs and is already supplying power to another RX, it may determine the GP value based on its current remaining power supply capacity instead of its own power supply capacity. Also, while S410 and S411 use the Negotiation phase communication of the WPC standard, they are not limited to this, and other procedures may be performed to determine the GP based on the results of equipment authentication between the TX and the RX. In addition, if the TX obtains information (for example in S402) indicating that the RX does not support the Negotiation phase, it may not perform the Negotiation phase communication and may set the GP value to a small value (for example, one predetermined in the WPC standard).

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

[0055] When the RX reaches full charge during the Power Transfer phase, it sends an End Power Transfer according to the WPC standard. This stops power transmission from the TX and completes the series of processes for wireless charging. After the series of processes for wireless charging is complete, if BLE was OFF when the RX was placed on the TX (YES in S414), it turns BLE OFF (S415) and terminates this process. Note that if the BLE connection is used by another application, it is not necessary to turn BLE OFF. On the other hand, if BLE was ON (NO in S414), nothing happens and this process terminates. After this, the RX may return to S401, or it may wait for another trigger, such as when the battery level drops below a certain level, before returning to S401.

[0056] Figure 5 is a flowchart showing an example of the BLE communication start determination process (S404) executed by the RX. This process can be implemented, for example, by the RX's control unit 201 executing a program read from the memory 210. At least part of the following procedure may be implemented by hardware. In this case, the hardware can be implemented, for example, by automatically generating a dedicated circuit using a gate array circuit such as an FPGA from a program to implement each processing step using a predetermined compiler. Furthermore, this process can be executed in response to receiving capability information from TX, but it may also be started by other triggers.

[0057] The RX checks in S403 whether the capability information obtained from the TX includes information indicating that device authentication via BLE communication is possible (S501). Whether or not information indicating that device authentication via BLE communication is possible is included can be determined by comparing, for example, bits indicating the ability to perform device authentication using outband communication included in the capability information, bits indicating the holding of BLE, and bits indicating whether BLE is in an usable state. If the capability information obtained from the TX includes information indicating that device authentication via BLE communication is possible (YES in S501), it determines whether its own BLE is ON or not (whether the BLE state is active or not) (S502). On the other hand, if the capability information obtained from the TX does not include information indicating that device authentication via BLE communication is possible (NO in S501), this process ends without doing anything.

[0058] If BLE is enabled (ON) (YES in S502), the RX determines whether BLE communication is possible via the second communication unit 207 (S503). Here, if the BLE communication function is in use with another application or communication device, or if the role of the BLE communication function is Peripheral, the RX determines that BLE communication is not possible. The RX may also determine that BLE communication is not possible if the battery level of 202 is low. If BLE communication is possible (YES in S503), the RX sends a BLE communication start request to the TX (S506) and terminates this process. The BLE communication start request may be made, for example, by an Out Of Band Request Packet (hereinafter referred to as "OOB Req Packet") of the WPC standard, or by another packet. On the other hand, if BLE communication is not possible (NO in S503), this process terminates without doing anything.

[0059] If BLE is disabled (BLE is not ON) (NO in S502), RX determines whether or not the user has permission to turn BLE ON (S504). User permission to turn BLE ON is done, for example, by displaying a query display 900, as shown in Figure 9(A), on the display unit 208 in full screen or as a pop-up window, and by the user selecting the area 901 in which they indicate permission. On the other hand, denial of BLE activation (turning BLE ON) is done by the user selecting the area 902 in the query display 900 in which they indicate denial. Note that the user's selection result may be stored, and if BLE ON was permitted in a previous operation, the query display 900 may not be displayed, and it may be assumed that permission has been granted.

[0060] Alternatively, an item 911 regarding permission to turn BLE ON may be displayed in the RX settings display 910 as shown in Figure 9(B), and permission may be granted by the user enabling item 911 in advance using button 912. In this case as well, the inquiry display 900 may not be displayed, and it may be assumed that turning BLE ON is permitted. Furthermore, if no operation is performed on the inquiry display 900 for a certain period of time, it may be assumed that turning BLE ON is not permitted.

[0061] If enabling BLE is permitted (YES in S504), after enabling BLE (ON) (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 power transmission equipment Next, an example of the processing flow executed by the TX will be explained using Figure 6. This processing can be implemented, for example, by the TX's control unit 301 executing a program read from the memory 310. At least a part of the following procedure may be implemented by hardware. In this case, the hardware can be implemented, for example, by automatically generating a dedicated circuit using a gate array circuit such as an FPGA from a program to implement each processing step using a predetermined compiler. Furthermore, this processing can be executed in response to the TX being powered on, in response to the TX user inputting a command to start a wireless charging application, or in response to the TX being connected to a commercial power source and receiving power. This processing may also be started by other triggers.

[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 Ping according to the WPC standard to detect objects within the power transmission range (Selection phase). Then, if the TX detects the presence of an object within the power transmission range, it transmits a Digital Ping. If a predetermined response is received to the Digital Ping, the TX determines that the detected object is an RX and that the RX has been placed on the charging stand 103 (Ping phase).

[0064] When the TX detects the presence of the RX, it performs the aforementioned I&C phase communication via in-band communication and obtains identification information and capability information from the RX (S602). Subsequently, it waits for a capability information acquisition request from the RX (S603). If a capability information acquisition request is received (YES in S603), the capability information is transmitted (S604); if it is not received (NO in S603), nothing is done and it waits for a BLE communication start request from the RX (S605).

[0065] In this embodiment, one bit from bits 6 to 7 (800) of Bank1 or bits 2 to 7 (801) of Bank2, which are the reserved areas of the TX Capability Packet in Figure 8, 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 the BLE bit to one of the reserved areas. If the TX has the capability to use BLE for outband communication, or has BLE that can be used for control communication, it writes "1" to the BLE bit; otherwise, it writes "0". Furthermore, the TX assigns the BLE Enable bit to one of the reserved areas. If the TX can use BLE as outband communication at that time, it writes "1" to the BLE Enable bit; otherwise, it writes "0". Note that the outband communication type may include bits related to NFC or Wi-Fi, and is not limited to the above form.

[0066] Returning to Figure 6, if the TX receives a BLE communication start request (YES in S605), it sends a BLE advertising packet containing the TX's identification information and establishes a BLE connection with the RX installed on its device (S606). Subsequently, the TX uses the BLE connection established in S606 to communicate with the RX as described in Figure 7(A) for device authentication (S607). On the other hand, if the TX does not receive a BLE communication start request from the RX in S605 (NO in S605), it uses in-band communication to communicate for device authentication as described in Figure 7(A) (S608). After that, the TX negotiates with the RX as shown in Figure 7(C) to determine the GP (S609). After determining the GP, the TX performs calibration (S610) and power transmission until fully charged (S611) based on that GP.

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

[0068] [3.3] System Operation The operation sequence of RX and TX, as explained using Figures 4 to 6, will be described under several assumed scenarios. Initially, it is assumed that RX is not mounted on TX, and TX has sufficient power transmission capacity to transmit power via the GP required by RX.

[0069] <Processing Example 1> First, let's explain Processing Example 1 using Figure 10. In Processing Example 1, TX is assumed to be a device that has the function of the second communication unit 307, i.e., outband communication using BLE, is in a state where BLE communication is possible, and successfully authenticates with RX. Furthermore, RX is assumed to have BLE OFF when installed, has not been given prior permission to turn BLE ON, and requires permission from the user to be obtained by querying whether or not to allow BLE ON.

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

[0071] When the RX receives capability information from the TX, it starts the BLE communication start determination process (S404). Since the TX's capability information includes information that device authentication via BLE communication is possible, the RX checks if its own BLE is ON (YES in S501, S502). The RX's own BLE is OFF and it has not been previously permitted to turn BLE ON, so it displays a 900 message asking whether to allow BLE to be turned ON (NO in S502, F1010). When the user allows BLE to be turned ON, the RX turns BLE ON (YES in S504, S505, F1011) and sends a BLE communication start request to the TX (S506, F1012). Upon receiving the BLE communication start request, the TX sends a BLE advertising packet (F1013), and the RX sends CONNECT_REQ (F1014), establishing a BLE connection (YES in S405, S406, S605, S606).

[0072] Next, communication for device authentication via BLE takes place, and device authentication is successful (S407, S607, F1015). Since device authentication was successful, GP = 15 watts is determined through negotiation between RX and TX (YES in S409, S410, S608, F1016). After that, calibration (S412, S609, F1017) and power transmission and reception until full charge are performed (S413, S610, F1018). Once fully charged, End Power Transfer is sent from RX and the process ends (F1019).

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

[0074] <Processing Example 2> Next, we will explain Processing Example 2 using Figure 11. In Processing Example 2, we assume that the initial state is that RX is not mounted on TX and BLE is OFF. We will also assume that the user has previously authorized BLE to be ON. The following explanation will focus on the differences from Figure 10.

[0075] In Figure 11, the process from placement detection to the transmission of capability information by the TX (F1101-F1109) is the same as in Figure 10 (F1001-F1009). When the RX receives capability information from the TX, it starts the BLE communication start determination process (S404). Since the RX has been given prior permission from the user to turn on BLE, it automatically turns on BLE without asking whether or not to allow it (NO in S502, YES in S504, S505, F1110). The subsequent operations until full charge (F1011-F1018) are the same as in Figure 10 (F1012-F1019). According to the operations described above, when the RX is placed on a TX capable of outband communication via BLE, it automatically turns on BLE without making the user aware of the BLE status, performs communication for device authentication, and receives power based on the result.

[0076] <Processing Example 3> Next, we will explain Processing Example 3 using Figure 12. In Processing Example 3, it is assumed that the initial state is that RX is not mounted on TX and BLE is OFF. Furthermore, it is assumed that the user has not previously permitted BLE to be ON, and that no user action is taken in response to the prompt asking whether or not to permit BLE to be ON, so ON is not permitted. The following explanation will focus on the differences from Figure 10.

[0077] In Figure 12, the process from placement detection to the display of the inquiry asking whether to allow BLE to be turned ON (F1201~F1210) is the same as in Figure 10 (F1001~F1010). Since there is no user operation for a certain period of time after the inquiry display, the RX terminates the inquiry display and assumes that BLE is not allowed to be turned ON (NO in S504, F1211). Since BLE is not allowed to be turned ON, the RX performs communication for device authentication via in-band communication and succeeds (NO in S405, S408, F1212). The subsequent operation until full charge (F1213~F1216) is the same as in Figure 10 (F1016~F1019).

[0078] According to the operation described above, the RX is mounted on a TX capable of out-band communication via BLE, and if the user does not authorize BLE to be turned on, it performs device authentication communication via in-band communication without turning on BLE, and receives power based on the result.

[0079] As explained in the above processing examples 1 to 3, the RX according to this embodiment can perform device authentication communication via outband communication by turning on BLE, even when it is mounted on a TX that is capable of outband communication via BLE with BLE turned OFF. Here, since outband communication is faster than inband communication, the time required for device authentication communication is shorter when using outband communication. Therefore, the time from when the RX is mounted until charging starts can be shortened. In addition, even if the user does not permit BLE to be turned ON, device authentication communication can be performed via inband communication, so charging can start regardless of the BLE state.

[0080] In this embodiment, if there is no user interaction 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 using in-band communication is performed, assuming that permission is not granted. However, it is not necessary to terminate the inquiry display. Also, if the user grants permission to turn BLE ON during device authentication using in-band communication, the device authentication using in-band communication may be interrupted, BLE may be turned ON, and the system may switch to device authentication using out-band communication. This shortens the time required for communication for device authentication compared to continuing device authentication using in-band communication, and thus shortens the time until charging can begin. 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 becoming longer 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, but other functions that can be executed using outband communication may also be applied. For example, it may be a firmware update for the TX. 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 the reserved area of ​​the TX Capability Packet, to the Firmware Update bit. If the TX has the capability to perform a firmware update using outband communication, it writes "1" to the Firmware Update bit; otherwise, it writes "0". By applying this to a function that requires communication of a large amount of data, the time required for communication for that function can be greatly reduced.

[0082] In this embodiment, it was explained that only one type of communication method, BLE, is used for outband communication. However, the RX is equipped with the ability to communicate using multiple communication methods, and any of these may be used for outband communication. In that case, the capability information transmitted and received in S402 and S403 in Figure 4 may include not only information on whether BLE communication is possible, but also information on whether communication using other communication methods is possible. Furthermore, in the BLE communication start determination process (S501~S506) in Figure 5, control may be implemented to turn on communication using other communication methods if they are OFF, depending on the received capability information. This makes it possible to perform device authentication in a short time using outband communication, which is faster than inband communication, regardless of whether it is installed on a BLE-enabled TX or a Wi-Fi-enabled TX.

[0083] In the above embodiment, an example was shown in which control information for device authentication, which is performed before the start of wireless power transmission, is transmitted and received using the second communication unit 207 of the RX and the second communication unit 307 of the TX. However, the control information transmitted and received by the above control is not limited to information used for device authentication, but 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 implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0085] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose 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, A power receiving means that receives power wirelessly from a power transmission device, It has communication means for communicating with the power transmission device, The aforementioned communication means is At a first frequency, the identification information of the power receiving device is transmitted to the power transmitting device. After transmitting the identification information, a request is sent to the power transmission device to communicate at the first frequency, but at a second frequency higher than the first frequency. After the transmission of the aforementioned request, communication regarding authentication processing to the power transmission device is performed at the second frequency. The power receiving device is characterized in that it further has means for performing a negotiation process regarding the power to be received from the power transmitting device after the authentication process.

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

3. The power receiving device according to claim 1 or 2, wherein the communication means transmits a request for information regarding an electronic certificate to the power transmitting device.

4. The power receiving device according to claim 3, wherein the communication means transmits a request for information regarding the electronic certificate and then receives information regarding the electronic certificate from the power transmitting device.

5. A method performed by a power receiving device, It receives power wirelessly from the power transmission equipment. At a first frequency, the identification information of the power receiving device is transmitted to the power transmitting device. After transmitting the identification information, a request is sent to the power transmission device to communicate at the first frequency, but at a second frequency higher than the first frequency. After the transmission of the aforementioned request, communication regarding authentication processing to the power transmission device is performed at the second frequency. A method characterized by performing a negotiation process regarding the power to be received from the power transmission device after the authentication process.

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