Power receiving apparatus and power transmitting apparatus

Abstract

The present application relates to a power receiving device and a power transmitting device. If control communication using the first communication unit 204 is switched to control communication using the second communication unit 202, the control unit 201 of the power receiving device 200 performs predetermined communication with the power transmitting device 100 via the first communication unit 204, so that power transmission from the power transmitting device 100 is continued.

Description

[0001] (This application is a divisional application of the application filed on October 25, 2019, with application number 2019800824731 and entitled "Power Receiving Device, Control Method for Power Receiving Device and Storage Medium".) Technical Field

[0002] This invention relates to a power receiving device, a control method for the power receiving device, and a procedure thereof. Background Technology

[0003] Extensive technical development has been undertaken on wireless power transmission systems. PTL 1 discloses power transmitting and receiving devices conforming to standards defined by the Wireless Power Consortium (WPC), the standardization body for contactless charging standards (WPC standards). These power transmitting and receiving devices exchange the control information required for power transmission through communication that superimposes information onto the power to be transmitted and received.

[0004] PTL 2 discloses a technique for communicating control signals via a communication unit using a frequency and coil (or antenna) different from those of the power transmitting unit and the power receiving unit. These control signals are executed between the power transmitting device and the power receiving device to control the transmission of power.

[0005] Existing technical documents

[0006] Patent documents

[0007] PTL1: Japanese Patent Application Publication No. 2016-007116

[0008] PTL2: Japanese Patent Application Publication No. 2012-217224 Summary of the Invention

[0009] Technical issues

[0010] Control communication in wireless power transmission systems includes both small and large data packets. However, in existing wireless power transmission systems capable of using multiple communication units for communication, these packets are not sent and received selectively using multiple communication units.

[0011] The present invention was made in view of the above problems, and the present invention provides a technique for properly controlling multiple communication units during wireless power transmission.

[0012] Technical means to solve the problem

[0013] The power receiving device according to the present invention, which achieves the above-mentioned objective, includes:

[0014] A power receiving unit, used to wirelessly receive power from a power transmitting device;

[0015] A first communication unit is used for control communication with the power transmitting device for wireless power transmission;

[0016] A second communication unit is configured to perform control communication with the power transmitting device for wireless power transmission using a method different from that used by the first communication unit; and

[0017] A control unit is configured to, when the control communication using the first communication unit is switched to the control communication using the second communication unit, perform predetermined communication with the power transmission device via the first communication unit, so that power transmission from the power transmission device continues.

[0018] Advantages of the invention

[0019] According to the present invention, multiple communication units can be appropriately controlled during wireless power transmission.

[0020] Other features and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings. Note that throughout the drawings, the same reference numerals denote the same or similar parts. Attached Figure Description

[0021] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0022] Figure 1 This is a block diagram illustrating an example arrangement of a power transmission device according to an embodiment;

[0023] Figure 2 This is a block diagram illustrating an example arrangement of a power receiving device according to an embodiment;

[0024] Figure 3 This is a timing diagram illustrating the operation of a wireless power transmission system according to an embodiment;

[0025] Figure 4A This is a flowchart illustrating the processing procedure performed by the power receiving device according to an embodiment;

[0026] Figure 4B This is a flowchart illustrating the processing procedure performed by the power receiving device according to an embodiment;

[0027] Figure 5A This is a flowchart illustrating the processing procedure performed by the power transmission device according to an embodiment;

[0028] Figure 5B This is a flowchart illustrating the processing procedures performed by the power transmission device according to an embodiment; and

[0029] Figure 6 This is a flowchart illustrating the process of preventing power transmission from stopping in relation to the power transmission device according to an embodiment. Detailed Implementation

[0030] The embodiments will now be described with reference to the accompanying drawings. Please note that the arrangements shown in the following embodiments are merely examples, and the invention is not limited to the arrangements illustrated.

[0031] <Arrangement of Power Transmission Equipment>

[0032] Figure 1 This is a block diagram illustrating an example arrangement of a power transmitting device suitable for a wireless power transmission system according to an embodiment. The power transmitting device 100 conforms to the WPC standard and supports a device authentication protocol. Note that while this embodiment describes the power transmitting and receiving devices as conforming to the WPC standard, the invention is not limited thereto, and they may conform to other wireless power transmission standards.

[0033] The power transmission device 100 includes a control unit 101, a power supply unit 102, a power transmission unit 103, a first communication unit 104, a power transmission coil 105, a second communication unit 106, a memory 107, and an authentication unit 108. The control unit 101 controls the entire power transmission device 100. An example of the control unit 101 is a CPU (Central Processing Unit). The power supply unit 102 provides at least enough power to operate the control unit 101 and the power transmission unit 103. The power transmission unit 103 generates power to be transmitted via the power transmission coil 105 to a location to be referred to later. Figure 2 The described power receiving device 200 describes the AC voltage and AC current. More specifically, the power transmitting unit 103 converts the DC voltage supplied by the power supply unit 102 into AC voltage via a switching circuit having a half-bridge or full-bridge configuration using FETs (field-effect transistors). The power transmitting unit 103 includes gate drivers that control the ON / OFF state of the FETs. The power transmitting unit 103 has the capability to supply power, for example, 15W, to the charging unit of the power receiving device 200 corresponding to the WPC standard.

[0034] The communication unit 104 and the communication unit of the power receiving device 200 ( Figure 2 The first communication unit 104 performs control communication for wireless power transmission based on the WPC standard. In this embodiment, the communication performed by the first communication unit 104 is as follows: the AC voltage or current generated by the power transmitting unit 103 is modulated and superimposed with a signal for wireless power transmission. In the following, the communication unit 104 communicates with the power receiving device 200's communication unit (…). Figure 2 The communication between the first communication units 204 in the middle is called the first communication.

[0035] The second communication unit 106 communicates with the power receiving device 200. Figure 2 The second communication unit 106 performs control communication for wireless power transmission based on the WPC standard. Communication performed by the second communication unit 106 uses a frequency different from that of the power transmitting unit 103 and uses an antenna (not shown) different from that of the power transmitting coil 105. In this embodiment, the second communication unit 106 is described as operating as a Bluetooth Low Energy (BLE) peripheral. However, the second communication unit 106 can be a BLE hub, or it can use Near Field Communication (NFC), Wi-Fi, etc. In this embodiment, the second communication unit 106 can perform communication at a higher speed than that performed by the first communication unit 104. Hereinafter, the communication unit 106 will communicate with the power receiving device 200 via the second communication unit 106. Figure 2 The communication between the second communication units 202 in the middle is called the second communication.

[0036] The second communication unit 106 is controlled by the control unit 101, but it can also be configured to be controlled by the control unit of other devices (camera, smartphone, tablet PC or laptop PC) (not shown) that are integrated with the power transmission device 100.

[0037] Memory 107 stores the states of power transmitting device 100 and power receiving device 200. Memory 107 also stores a computer program for operating power transmitting device 100. Authentication unit 108 executes a device authentication protocol with power receiving device 200 via first communication unit 104 or second communication unit 106.

[0038] Note that in Figure 1 In the example shown, the control unit 101, power supply unit 102, power transmission unit 103, first communication unit 104, memory 107 and second communication unit 106 are described as separate entities, but some of them may be installed in the same chip.

[0039] <Arrangement of Power Receiving Equipment>

[0040] Next, Figure 2 This is a block diagram illustrating an example arrangement of a power receiving device suitable for a wireless power transmission system according to an embodiment. The power receiving device 200 conforms to the WPC standard, includes the functions described in WPC standard v1.2.2, and supports a device authentication protocol.

[0041] The power receiving device 200 includes a control unit 201, a second communication unit 202, a power receiving unit 203, a first communication unit 204, a power transmitting coil 205, a charging unit 206, a battery 207, a memory 208, and an authentication unit 209.

[0042] Control unit 201 controls the entire power receiving device 200. An example of control unit 201 is a CPU. Power receiving unit 203 converts the AC voltage and AC current received via power receiving coil 205 from power transmitting coil 105 into DC voltage and DC current for operating control unit 201, charging unit 206, etc. Power receiving unit 203 provides the power used by charging unit 206 to charge battery 207 and has the power supply capability to output 15W of power to charging unit 206.

[0043] The first communication unit 204 communicates with the first communication unit 104 of the power transmitting device 100 for control communication based on the WPC standard for wireless power transmission. This control communication is performed by load modulation of the electromagnetic waves received by the power receiving coil 205.

[0044] The second communication unit 202 performs control communication with the second communication unit 106 of the power transmitting device 100 based on the WPC standard for wireless power transmission. The communication performed by the second communication unit 202 uses a frequency different from that of the power transmitting unit 103 of the power transmitting device 100, and uses an antenna (not shown) different from that of the power transmitting coil 105. In this embodiment, the second communication unit 202 is described as corresponding to the center of BLE. However, the second communication unit 202 can be a peripheral of BLE, or it can use near field communication (NFC), Wi-Fi, etc. In this embodiment, the second communication unit 202 can perform communication at a higher speed than the communication performed by the first communication unit 204.

[0045] The second communication unit 202 is controlled by the control unit 201, but it can also be configured to be controlled by the control unit of other devices (camera, smartphone, tablet PC or laptop PC) (not shown) that are integrated with the power receiving device 200.

[0046] Memory 208 stores the states of power transmitting device 100 and power receiving device 200. Memory 208 also stores a computer program for operating power receiving device 200. Authentication unit 209 executes a device authentication protocol with power transmitting device 100 via first communication unit 204 or second communication unit 202.

[0047] <Function and State Transition>

[0048] Here, we will proceed from... Figure 3The relevant parts are extracted to schematically describe the functions and state transitions of the power transmitting device 100 and the power receiving device 200 conforming to the WPC standard. Figure 3 This is a timing diagram of a power transmitting device and a power receiving device suitable for a wireless power transmission system according to an embodiment.

[0049] If the power transmitting device 100 is activated, the power transmitting unit 103 transmits an analog Ping (F300) via the power transmitting coil 105. The analog Ping is a small electrical signal used to detect objects present in the vicinity of the power transmitting coil 105. When the power transmitting device 100 is transmitting an analog Ping, the power transmitting device 100 is in the selection phase.

[0050] When transmitting a simulated Ping, the power transmitting device 100 detects the voltage or current value of the power transmitting coil 105. If the voltage is less than a certain threshold or the current is greater than a certain threshold, it is determined that an object exists near the power transmitting coil 105, and the power transmitting device 100 switches to the Ping phase.

[0051] During the Ping phase, the power transmitting device 100 transmits a digital Ping (F301) with a power greater than that of the analog Ping. The digital Ping has a power sufficient to activate the power receiving device 200 and the control unit 201, which are at least present in the vicinity of the power transmitting coil 105.

[0052] The control unit 201 of the power receiving device 200 is activated by the power received (digital ping) via the power receiving coil 205. If the control unit 201 is activated, it notifies the power transmitting device 100 of the magnitude of the received voltage (F302) and transitions to the Identification & Configuration (I&C) phase. Here, the received voltage is notified via a first communication through the first communication unit 204.

[0053] If a received voltage notification is received from the power receiving device 200, the power transmitting device 100 transitions to the I&C phase. Then, the power receiving device 200 sends an ID packet (F303) to the power transmitting device 100, including a manufacturer code and device identification information indicating the manufacturer of its own device. The power transmitting device 100 also sends a configuration packet (F304) to the power transmitting device 100, including the standard version it conforms to, etc.

[0054] The power transmitting device 100 receives a configuration packet from the power receiving device 200 and determines whether the corresponding standard version of the power receiving device 200 is equal to or higher than, for example, version v1.2.2. If the standard version is equal to or higher than version v1.2.2, the power transmitting device 100 sends an ACK (F305) to the power receiving device 200 indicating that the information included in the configuration packet has been acknowledged. Then, the power transmitting device 100 transitions to the negotiation phase (F319). Similarly, if an ACK (F305) is received, the power receiving device 200 transitions to the negotiation phase (F319). Note that predetermined processing operations specific to this embodiment (F306 to F318, F323, and F324) will be described later.

[0055] During the negotiation phase (F319), the power transmitting device 100 and the power receiving device 200 negotiate to determine a guaranteed power (hereinafter referred to as "GP") that indicates the amount of power that the power receiving device 200 is certain to receive. More specifically, the power receiving device 200 notifies the power transmitting device 100 of a value to be used as a GP candidate. The power transmitting device 100 accepts or rejects the notification. Since the power receiving device 200 has the power supply capability to output 15W of power to the charging unit 206, it can notify a maximum of 15W as a candidate GP value. The power transmitting device 100 can accept a maximum of 15W as the GP value.

[0056] If the GP negotiation terminates, the power transmitting device 100 and the power receiving device 200 transition to the calibration phase (F320). While details will not be described, during the calibration phase (F320), the parameters required for the foreign object detection function are determined, in which the power transmitting device 10 detects the presence of an object different from the power receiving device 200 in the vicinity of the power transmitting coil 105. During the calibration phase, the power receiving device 100 also performs the process of supplying power from the power receiving unit 203 to the charging unit 206, which serves as a load. Afterward, the power transmitting device 100 and the power receiving device 200 transition to the power transmission phase (F321), and the power receiving device 200 charges the battery 207.

[0057] The above is a schematic description of the functions and state transitions of the WPC-compliant power transmitting device 100 and power receiving device 200.

[0058] <Equipment Certification>

[0059] Next, device authentication will be described. Device authentication is a process that confirms the mutual validity between the power transmitting device 100 and the power receiving device 200, and it is a bidirectional process. More specifically, the power transmitting device 100 can confirm the validity of the power receiving device 200, or the power receiving device 200 can confirm the validity of the power transmitting device 100. The amount of power to be transmitted / received is determined based on the result of the device authentication.

[0060] More specifically, for a power receiving device whose validity cannot be verified, the power transmitting device 100 transmits less power than it would transmit to a power receiving device 200 whose validity can be verified. Therefore, during the negotiation phase, for a power receiving device whose validity cannot be verified, the power transmitting device 100 only accepts a smaller GP than that of a power receiving device whose validity can be verified, and does not accept 15W, which is the maximum GP that its own device can provide. A power receiving device whose validity cannot be verified may be a poor-quality power receiving device, potentially generating excessive heat compared to a valid power receiving device. With the construction described above, excessive heat generation can be prevented.

[0061] Similarly, for a power transmitting device whose validity cannot be verified, the power receiving device 200 requests a smaller GP than the power to be received from a valid power transmitting device. That is, during the negotiation phase, the power receiving device 200 does not request 15W, the maximum GP of its own device, from a power transmitting device whose validity cannot be verified. A power transmitting device whose validity cannot be verified may be a substandard device, potentially generating excessive heat compared to a valid power transmitting device. With the configuration described above, excessive heat generation can be prevented.

[0062] Device certification is performed before the negotiation phase. This is because the outcome of device certification affects the size of the General Protocol (GP) negotiated during the negotiation phase. If device certification were performed after the GP had been determined during the negotiation phase, unnecessary processing could occur, such as reverting to the negotiation phase and renegotiating the GP based on the device certification results.

[0063] To terminate device authentication processing earlier, a method is used to authenticate the device via a second communication that is faster than the first communication.

[0064] Here, we will describe the situation where device authentication has already been performed via a second communication. First, according to the WPC standard, there is a mechanism whereby power transmitting device 100 stops power transmission if it cannot detect power receiving device 200. Using this mechanism, power transmitting device 100 can stop power transmission when it cannot be detected because power receiving device 200 is physically far away from power transmitting device 100. Therefore, it prevents the following situation: power transmitting device 100 continuously transmits unnecessary radio waves even when power receiving device 200 is not within power transmission range.

[0065] More specifically, in the I&C phase, after the power transmitting device 100 receives the end of a packet sent by the first communication unit 204 of the power receiving device 200, if the start of the next packet is not received within a predetermined time (25ms), the power transmitting device 100 stops power transmission. Furthermore, in the negotiation phase, after the power transmitting device 100 sends a response to a packet sent by the first communication unit 204 of the power receiving device 200, if the next packet is not received within a predetermined time (250ms), the power transmitting device 100 stops power transmission. Similarly, in the power transmission phase, after the power transmitting device 100 receives the end of a packet sent by the first communication unit 204 of the power receiving device 200, if the start of the next packet is not received within a predetermined time (1500ms), the power transmitting device 100 stops power transmission. In this way, the power transmitting device 100 has the function of stopping power transmission due to timeout.

[0066] After the I&C phase ends and the device transitions to the negotiation phase, if device authentication (control communication) is performed via the second communication, GP negotiation is conducted based on the result of the device authentication performed via the second communication for the reasons described above. Therefore, there are no packets to be transmitted from the power receiving device via the first communication. In this case, as described above, the power transmitting device does not receive a packet from the power receiving device via the first communication within a predetermined time, causing power transmission to stop. Furthermore, retransmissions may occur in the second communication due to interference with other wireless communications, therefore the first communication will not be performed for an extended period.

[0067] Conversely, even during device authentication via the second communication with the power transmitting device, the power receiving device according to this embodiment also sends packets to the power transmitting device via the first communication. Therefore, it is possible to prevent the power transmitting device from ceasing power transmission.

[0068] <Operation Sequence of Wireless Power Transmission Systems>

[0069] reuse Figure 3This section describes the detailed process of a wireless power transmission system comprising a power transmitting device 100 and a power receiving device 200. As described above, the power transmitting device 100 transmits an analog Ping (F300). If it is determined that an object exists near the power transmitting coil, the power transmitting device 100 transmits a digital Ping (F301). If the power receiving device 200 receives the digital Ping (F301), it activates the control unit 201. Then, the power receiving device 200 notifies the power transmitting device 200 of the received digital Ping voltage (F302) and transitions to the I&C phase.

[0070] The power receiving device 200 sends an ID packet (F303) and a configuration packet (F304) to the power transmitting device 100 via the first communication unit 104. If the configuration packet is received, the power transmitting device 200 sends an ACK (F305). If the ACK (F305) is received, the power receiving device 200 sends an OOB request (OOB Req) (F306).

[0071] Assume that, based on the configuration package, power receiving device 200 is determined to support device authentication, and further supports device authentication using BLE. Assume that power transmitting device 100 also supports device authentication, and further supports device authentication using BLE. Therefore, power transmitting device 100 sends an ACK (F307) indicating that it accepts device authentication using BLE.

[0072] If an ACK (F307) is received, the power receiving device 200 begins transmitting IDLE (idle) (F308) via the first communication unit 104. The power transmitting device 100 transmits an ACK for IDLE (F323). Here, if the power receiving device 200 does not receive an ACK for IDLE, the power receiving device 200 may transmit an EPT indicating to stop power transmission to the power transmitting device 100. If the power receiving device 200 receives a packet other than an ACK for IDLE, for example, if it receives NAK or ND (undefined), the power receiving device 200 may also transmit an EPT.

[0073] The ND packet is a response packet sent by the power transmitting device 100 when it cannot understand a packet sent by the power receiving device 200. If the power transmitting device 100 has already sent an ACK (F307) to the power receiving device 200 for an OOB Req received from the power receiving device 200, the power transmitting device 100 should be able to understand this as an intention to send an IDLE to avoid power transmission stopping due to timeout. However, if the power receiving device 200 receives a NAK or ND (F323) from the power transmitting device 100, the power receiving device 200 interprets this as a malfunction of the power transmitting device 100, and it can stop power transmission by sending an EPT.

[0074] Then, the power transmitting device 100 transmits ADV (F309) via the second communication unit 106. The power receiving device 200 transmits CONNECT (F311) via the second communication unit 202. Subsequently, the power receiving device 200 transmits an authentication request (Auth Req) (F312). After receiving an ACK (F313) from the power transmitting device 100, the power receiving device 200 performs authentication (Auth) processing in which it operates as the initiator (F314).

[0075] Even when the power transmitting device 100 and the power receiving device 200 are conducting control communication via a second communication, the power receiving device 200 sends an IDLE (F310 and F324) before a predetermined time has elapsed (e.g., periodically). The power transmitting device 100 responds to the IDLE with an ACK (not shown). Subsequently, the power transmitting device 100 sends an Auth Req (F315). After receiving an ACK (F316) from the power receiving device 200, the power transmitting device 100 performs Auth processing (F317) in which it operates as the initiator.

[0076] If the Auth process terminates, the power receiving device 200 sends a TERMINATE (F318) message to the power transmitting device 100 and terminates BLE communication. Because the Auth process terminates, the power transmitting device 100 and the power receiving device 200 negotiate the GP (F319), transition to the calibration phase (F320), and then to the PT phase (F321).

[0077] Here, as defined by the WPC standard: after power receiving device 200 sends a specific request packet of type "Guarantee Power" and notifies power transmitting device 100 of the desired GP, power transmitting device 100 and power receiving device 200 send / receive packets at a predetermined time. Therefore, power transmitting device 100 will not stop power transmission due to timeout thereafter. Thus, power receiving device 200 stops transmitting to prevent timeout-related IDLE.

[0078] As described above, when control communication is performed via the second communication, the power receiving device sends an IDLE via the first communication to prevent the power transmitting device from stopping power transmission. Further, after negotiation of the GP (GP) where there are packets to be transmitted via the first communication, the transmission of the IDLE is stopped. This stops the transmission of unnecessary packets and reduces processing.

[0079] Note that when the power transmitting device 100 is performing the second communication, there may be a situation where the second communication unit 106 cannot be used. For example, a device (not shown) that merges with the power transmitting device 100 may occupy the second communication unit 106. In this case, the power transmitting device 100 may be configured to use NAK to respond to IDLE if it is determined that the second communication unit 106 cannot be used for the second communication.

[0080] If a NAK is received, the power receiving device 200 switches the control communication from the second communication to the first communication. More specifically, after receiving a NAK, if no TERMINATE is received, the power receiving device 200 sends a TERMINATE. Then, the control communication that was previously conducted via the second communication resumes via the first communication. Of course, there are packets to be sent via the first communication when switching to it. Therefore, there is no need to send an IDLE, causing the power receiving device 200 to stop sending IDLEs. Thus, communication with the power transmitting device 100 can continue even when the second communication is unavailable.

[0081] The power for the second communication unit 202, which operates the power receiving device 200, is supplied by the battery (not shown) of the power receiving device 200. If the battery power is insufficient to drive BLE, the power receiving device 200 can store "0" in the BLE bit of the configuration packet. Similarly, if the device (not shown) that merges the power receiving device 200 is using BLE and therefore BLE cannot be used for authentication processing (control communication), the power receiving device 200 can store "0" in the BLE bit of the configuration packet. With this configuration, even if the power receiving device 200 cannot use BLE for the second communication, the problem of the power transmitting device 100 transmitting ADV can be avoided.

[0082] <Processing of Power Receiving Devices>

[0083] Next, we will refer to Figure 4A and Figure 4B The flowchart describes the processing procedure performed by the power receiving device 200 according to this embodiment. First, in step S401, the power receiving device 200 performs a reference... Figure 3 The description covers the processing in the selection phase and the processing in the Ping phase.

[0084] In step S402, the power receiving device 200 sends an ID packet and a configuration packet to the power transmitting device 100. Here, in the configuration packet, the power receiving device 200 informs the power transmitting device 100 that it supports device authentication and that device authentication can be performed using BLE second communication. More specifically, by using an unused reserved area in the configuration packet of the WPC standard, a configuration packet with the authentication bit (hereinafter referred to as the Auth bit) set to "1" and the BLE bit set to "1" is sent to the power transmitting device 100. The Auth bit is used to indicate that the power receiving device 200 supports device authentication. The BLE bit is used to indicate that device authentication can be performed using BLE second communication.

[0085] In step S403, the power receiving device 200 determines whether it has received an ACK for the configuration packet from the power transmitting device. According to WPC standard v1.2.2, if an ACK for the configuration packet is received, the power receiving device 200 can identify that the power transmitting device is in the negotiation phase. If an ACK is received, the power receiving device 200 transitions to the negotiation phase and proceeds to step S404. On the other hand, if no ACK is received, the process proceeds to step S418.

[0086] In step S404, the power receiving device 200 sends an out-of-band request (OOB Request) packet via the first communication unit 202, indicating a request for a second communication using BLE. Sending the OOB Request packet confirms that the power receiving device 100 supports BLE as the second communication unit 104 and further supports device authentication using the second communication unit 104.

[0087] The OOB Req packet includes a BLE bit. Setting the BLE bit to "1" indicates a request to use BLE as a secondary communication method. The OOB Req packet also includes an Auth bit. Setting the Auth bit to "1" indicates a request to use a secondary communication method for device authentication.

[0088] An OOB Req packet may include an NFC bit, indicating a request to use NFC as the secondary communication method. Setting the NFC bit to "1" indicates a request to use NFC as the secondary communication method. Similarly, an OOB Req packet may include a Wi-Fi bit, indicating a request to use Wi-Fi as the secondary communication method. Furthermore, reserved or proprietary packets with undefined packet types may be defined as OOB Req packets within general or specific request packets defined by the WPC standard.

[0089] In step S405, the power receiving device 200 determines whether it has received an ACK from the power transmitting device 100 as a response to the OOB Req. If the power receiving device 200 receives an ACK from the power transmitting device 100 as a response to the OOB Req, the power receiving device 200 can identify that the power transmitting device 100 supports BLE as the second communication unit 104 and further supports device authentication using the second communication unit 104. If an ACK is received, the process proceeds to step S406. On the other hand, if no ACK is received, the process proceeds to step S420.

[0090] In step S406, during the period from the transition to the negotiation phase to the GP negotiation, the power receiving device 200 periodically sends IDLE to the power transmitting device 100 via the first communication unit 204 at timings defined by the WPC standard. IDLE corresponds to, for example... Figure 3 Each of F308, F310, and F324. More specifically, starting from the end of the response packet (e.g., ACK) to IDLE sent by the power transmitting device 100 via the first communication unit 104 (i.e., the end of the previous packet), the power receiving device 200 sends the next IDLE packet within a maximum of 19 ms as defined by the WPC standard. Here, the IDLE packet is a periodically sent packet to prevent the power transmitting device 100 from stopping power transmission during control communication performed by the second communication.

[0091] If an IDLE is received, the power transmitting device 100, which understands the OOB Request, can send an ACK in response. Since the power transmitting device 100 periodically receives IDLEs, it will not stop power transmission due to timeout. Therefore, in the case of device authentication via the second communication, it is possible to prevent the power transmitting device from stopping power transmission due to not receiving a packet via the first communication within a predetermined time.

[0092] Note that since the purpose of the IDLE sent by the power receiving device 200 is to prevent the power transmitting device 100 from determining that a timeout has occurred, other packets can be used. For example, reserved packets or proprietary packets with undefined packet types can be used in general request packets or specific request packets.

[0093] Then, in step S407, the power receiving device 200 determines whether it has received an Advertising Indication Packet (hereinafter referred to as ADV) from the second communication unit 104 of the power transmitting device 100 within a predetermined time after receiving the ACK in step S405. Here, ADV is information sent by a BLE peripheral. ADV stores the Bluetooth device address (hereinafter referred to as BD address) as entity identification information of the peripheral and supported profile information (service information). If ADV is received within the predetermined time, the process proceeds to step S408. On the other hand, if ADV is not received within the predetermined time, the process proceeds to step S421.

[0094] Note that, in order to determine whether the ADV received by the power receiving device 200 is an ADV sent by the power transmitting device 100, the power receiving device 200 may pre-receive the BD address of the second communication unit 104 of the power transmitting device 100. More specifically, after receiving the ACK in step S405, the power receiving device 200 sends a packet to the power transmitting device 100 via the first communication unit 204, which is defined by the WPC standard as a packet for querying capabilities. Then, in response to this packet, the power transmitting device 100 may send a response containing the stored BD address to the power receiving device 200 via the first communication unit 104. Alternatively, a new packet for querying the BD address may be allocated. For example, a reserved packet or proprietary packet of undefined packet type may be allocated in a general request packet or a specific request packet.

[0095] By receiving the BD address of the power transmitting device 100 and determining whether it matches the BD address received via the second communication unit 202, the power receiving device 200 can determine whether it has received ADV from the power transmitting device 100.

[0096] In step S408, the power receiving device 200 sends a connection packet via the second communication unit 202, indicating that it will connect to the power transmitting device 100 via BLE.

[0097] In step S409, after enabling data transmission / reception with the power transmitting device 100 via BLE, the power receiving device 200 sends an Auth Req packet to the power transmitting device 100 via the second communication unit 202. The Auth Req packet is a packet used to indicate a request for device authentication to verify the validity of the power transmitting device 100.

[0098] The Auth Req packet includes information that the source of the request packet (power receiving device 200) acts as the initiator, which confirms the validity of the destination (power transmitting device 100), and the destination acts as the responder, which confirms its validity.

[0099] In step S410, the power receiving device 200 determines whether it has received an ACK indicating acceptance of the Auth Req from the power transmitting device 100. If an ACK indicating acceptance is received, the process proceeds to step S411. Otherwise, if no ACK indicating acceptance is received, the process proceeds to step S412.

[0100] In step S411, the power receiving device 200 performs authentication as a device authentication protocol. The authentication process (hereinafter referred to as the Auth process) is one of the authentication protocols that uses digital certificates. In the Auth process, the power receiving device 200 verifies the validity of the power transmitting device 100.

[0101] If the validity of the power transmitting device 100 is confirmed in step S411, or if no ACK is received in step S410, then in step S412, the power receiving device 200 determines whether it has received an Auth Req from the power transmitting device 100 via the second communication unit 202 within a predetermined time. The Auth Req includes information indicating that the power transmitting device 100 operates as an initiator confirming the validity of the sending destination (power receiving device 200), and that the power receiving device 200, as the sending destination, operates as a responder confirming its validity. If an Auth Req is received, the process proceeds to step S413. Conversely, if no Auth Req is received, the process proceeds to step S414.

[0102] In step S413, the power receiving device 200 performs authentication in which it operates as a responder. Here, if the power receiving device 200 cannot verify the validity of the power transmitting device 100 during the Auth processing in step S411, i.e., if device authentication fails, it is not preferable to perform Auth processing in which the power transmitting device 100 operates as an initiator. In this case, the BLE connection can be disconnected without waiting for the Auth Request sent by the power transmitting device 100. This is because, regardless of the result of the Auth processing in which the power transmitting device 100 operates as an initiator, the validity of the power transmitting device 100 cannot be verified, and therefore, the GP requested to the power transmitting device 100 needs to be limited during the negotiation phase described later. By avoiding useless Auth processing, the processing speed until power transmission begins can be increased. Note that the power receiving device 200 can be configured to store identification information (e.g., BD address or identification information defined by the WPC standard) of power transmitting devices whose validity cannot be verified in memory, so that a BLE connection is not subsequently established with that power transmitting device.

[0103] In step S414, the power receiving device 200 sends a termination instruction (hereinafter referred to as TERMINATE) to the power transmitting device 100 via the second communication unit 202, indicating that the BLE connection has been disconnected.

[0104] In step S415, the power receiving device 200 determines that after disconnecting BLE, it will not use the second communication unit 202 but will use the first communication unit 204, and will stop sending IDLE packets. In this way, by sending IDLE packets to the power transmitting device 100 via the first communication unit 204 while using the second communication unit 202, the power transmitting device 100 can be prevented from stopping power transmission.

[0105] Furthermore, by sending IDLE packets during device authentication without GP negotiation, the following scenario can be prevented: if GP negotiation is performed via the first communication during device authentication via BLE, GP renegotiation would be required after device authentication is terminated. IDLE transmission is stopped when BLE is disconnected and control communication using the second communication is not performed. This configuration avoids sending unnecessary packets and reduces the processing load on the control unit.

[0106] In step S416, the power receiving device 200 and the power transmitting device 100 negotiate the GP. Here, if the validity of the power transmitting device 100 has been confirmed, the power receiving device 200 requests a maximum value of 15W as the GP via the second communication unit 202. In this case, since the power transmitting device 100 has also confirmed the validity of the power receiving device 200, the power transmitting device 100 accepts the request from the power receiving device 200 within a range not exceeding 15W (the maximum value of the GP of the power transmitting device 100).

[0107] Subsequently, in step S417, the power receiving device 200 transitions to the calibration phase. In step S418, the power receiving device 200 transitions to the PT phase and provides a maximum of 15W of power to the charging unit 206 using the power received from the power transmitting device 100. If charging is terminated, in step S419, the power receiving device 200 sends a End Power Transmission (EPT) instruction to the power transmitting device 100 via the first communication unit 204, indicating the cessation of power transmission.

[0108] In step S420, the power receiving device 200 determines whether it has received a NAK (Not Accepted) signal used as a rejection response. If a NAK is received, the process proceeds to step S423. On the other hand, if no NAK is received, the process proceeds to step S418, and the power receiving device 200 switches to the PT (Power Tolerance) stage and begins charging, while setting the received power to a maximum of 5W.

[0109] In step S421, the power receiving device 200 determines that it will use the first communication instead of the second communication for authentication. In step S422, the power receiving device 200 stops sending IDLE. In step S423, the power receiving device 200 performs authentication via the first communication through the first communication unit 204. Afterward, the power receiving device 200 proceeds to step S416 and performs GP negotiation.

[0110] Based on the above series of processes, the power transmitting device and the power receiving device can appropriately control the first communication and the second communication.

[0111] As described above, the time for receiving ADV in step S407 is limited to a predetermined time after receiving ACK in step S405. With this configuration, device authentication can be performed via the first communication even in cases where the BLE of the power transmitting device 100 or the power receiving device 200 is not operating properly, or ADV cannot be received due to poor radio wave conditions. Furthermore, if it is determined in step S421 that device authentication will be performed via the first communication, the transmission of IDLE is stopped in step S422. This prevents the transmission of useless packets.

[0112] Note that the following example has been described, in which the power receiving device 200 performs authentication via first communication in step S423 if ADV is not received within a predetermined time; however, the invention is not limited to this example. A similar effect can be achieved by constructing a system in which authentication is performed via first communication if BLE communication is not initiated or a BLE connection cannot be established within a predetermined time.

[0113] Furthermore, an example has been described in which the power receiving device 200 sends an OOB Req to confirm that the power transmitting device 100 supports BLE as a second communication unit 104 and further supports device authentication using the second communication unit 104.

[0114] However, the present invention is not limited thereto, and the capabilities of the power transmitting device 100 can be queried before sending the OOB Request. More specifically, the power receiving device 200 sends a general request (power transmitter capability) via the first communication unit 204 before sending the OOB Request, where the description in parentheses indicates the packet type. The general request (power transmitter capability) is defined as a packet in the general request packet defined by the WPC standard for querying the capabilities of the power transmitting device. Then, the power transmitting device 100 can send a power transmitter capability packet to the power receiving device 200 via the first communication unit 104. The power transmitter capability packet is a packet including a BLE bit, an Auth bit, and an enable bit. The BLE bit is used to indicate support for BLE as a second communication. The Auth bit is used to indicate support for device authentication processing using BLE. The enable bit is used to indicate whether authentication processing using BLE can be performed at present.

[0115] The power receiver 200 is configured to send an OOB request if the BLE bit is "1", the Auth bit is "1", and the enable bit is "1". Otherwise (if the second communication unit 202 cannot perform device authentication), the power receiver 200 is configured not to send an OOB request. This configuration prevents the sending of useless OOB requests.

[0116] Note that if the power transmitter 100 or a device incorporating the power transmitter 100 (not shown) is using BLE and therefore BLE cannot be used for authentication processing (control communication), the power transmitter 100 stores "0" in the enable bit. Similarly, if a battery (not shown) provides power for operating the BLE and the battery power is insufficient to operate the BLE, the power transmitter 100 stores "0" in the enable bit.

[0117] The power transmitting device 100 may include a third communication unit (e.g., NFC) (not shown) that is different from the second communication unit 104. In this case, a bit for indicating support for the third communication unit, a bit for indicating support for device authentication using the third communication unit, and an enable bit for indicating whether authentication processing using the third communication unit can be performed at present may be provided.

[0118] This configuration allows for flexible control if the power receiving device 200 and the power transmitting device 100 support multiple second communications. For example, consider the case where the power transmitting device 100 and the power receiving device 200 support BLE and NFC as second communications. If the power transmitting device 100 cannot use BLE for device authentication (Auth bit or enable bit is "0"), but can use NFC for device authentication (Auth bit and enable bit are both "1"), then NFC-based device authentication can be performed. In this case, the power receiving device 200 sends an OOB request with the NFC bit set to "1" and the Auth bit set to "1".

[0119] <Processing of Power Transmission Devices>

[0120] Next, we will refer to Figure 5A and Figure 5B The flowchart describes the processing procedure performed by the power transmission device 100 according to this embodiment.

[0121] In step S501, the power transmitting device 100 performs the processing in the selection phase and the processing in the Ping phase. In step S502, the power transmitting device 100 receives an ID packet and a configuration packet from the power receiving device 200. By receiving the configuration packet, the power transmitting device 100 can identify that the power receiving device 200 supports device authentication and that the power receiving device 200 can perform device authentication using BLE second communication.

[0122] In step S503, the power transmitting device 100 sends an ACK via the first communication unit 104. In step S504, the power transmitting device 100 determines whether it has received an OOB Req sent from the power receiving device 200. If an OOB Req is received, the process proceeds to step S505. Otherwise, if no OOB Req is received, the process proceeds to step S522.

[0123] In step S505, the power transmitting device 100 determines whether it can currently use BLE for device authentication. If BLE can be used, the process proceeds to step S506. Otherwise, if BLE cannot be used, the process proceeds to step S521.

[0124] In step S506, the power transmitting device 100 sends an ACK to the power receiving device 200 as a response to the OOB Req. After sending the ACK, in step S507, the power transmitting device 100 sends an ADV via the second communication unit 106 within a predetermined time. In step S508, the power transmitting device 100 determines whether a connection has been received from the power receiving device 200. If a connection is received, the process proceeds to step S509. Otherwise, if no connection is received, the process proceeds to step S522.

[0125] Then, in step S509, the power transmitting device 100 determines whether it has received an Auth Req packet from the power receiving device 200 requesting the power receiving device 200 to act as the initiator. If an Auth Req packet is received, the process proceeds to step S510. On the other hand, if no Auth Req packet is received, the process proceeds to step S512.

[0126] In step S510, the power transmitting device 100 sends an ACK in response to the receipt of the Auth Req packet. In step S511, the power transmitting device 100 performs Auth processing in which it operates as the responder. After the Auth processing terminates, in step S512, the power transmitting device 100 sends an Auth Req to the power receiving device 200 requesting that it operate as the initiator of the Auth processing. If a connection is received and BLE-based communication is enabled ("Yes" in step S508), but no Auth Req requesting the power transmitting device 100 to operate as the responder is received within a predetermined time ("No" in step S509), the process also proceeds to step S512. Similarly, in this case, in step S512, the power transmitting device 100 sends an Auth Req to the power receiving device 200 requesting that it operate as the initiator of the Auth processing.

[0127] In step S513, the power transmitting device 100 determines whether it has received an ACK for the Auth Req sent in step S512 from the power receiving device 200. If an ACK is received, the process proceeds to step S514. Otherwise, if no ACK is received, the process proceeds to step S515.

[0128] In step S514, the power transmitting device 100 performs authentication processing in which it operates as the initiator. In step S515, the power transmitting device 100 determines whether it has received an termination from the power receiving device 200. If an termination is received, the process proceeds to step S517. Otherwise, if no termination is received, the process proceeds to step S516. In step S516, the power transmitting device 100 sends an termination to the power receiving device 200 and terminates communication via the second communication unit 106.

[0129] In step S517, the power transmitting device 100 negotiates the GP with the power receiving device 200 during the negotiation phase. Here, if the validity of the power transmitting device 100 has been confirmed, the power receiving device 200 requests a maximum value of 15W as the GP. In this case, since the power transmitting device 100 has also confirmed the validity of the power receiving device 200, the power transmitting device 100 accepts the request from the power receiving device 200 within the range of no more than 15W (the maximum value of the GP of the power transmitting device 100).

[0130] Subsequently, in step S518, the power transmitting device 100 transitions to the calibration phase. In step S519, the power transmitting device 100 transitions to the PT phase and provides a maximum of 15W of power to the charging unit 206 of the power receiving device 200.

[0131] If charging is terminated, in step S520, the power transmitting device 100 receives an EPT sent via the first communication unit 204 of the power receiving device 200, indicating to stop power transmission.

[0132] If BLE cannot be used when receiving an OOB Req in step S504 ("No" in step S505), then in S521, the power transmitting device 100 sends a NAK to the power receiving device 200. Then, the process proceeds to step S522.

[0133] In step S522, the power transmitting device 100 determines that it will use the first communication instead of the second communication for authentication processing. Then, in step S523, authentication processing is performed via the first communication. After this, the process proceeds to step S517.

[0134] Note that if the power transmitting device 100 cannot verify the validity of the power receiving device 200 in step S511, i.e., if device authentication fails, the power transmitting device 100 may not send an Auth Req and may disconnect the BLE connection. This operation is performed to avoid Auth processing in which the power transmitting device 100 acts as the initiator.

[0135] The reason for this is that, regardless of the outcome of the Auth processing initiated by the power transmitting device 100, the validity of the power transmitting device 100 cannot be confirmed. Therefore, the power transmitting device 100 needs to restrict the GP requested by the power receiving device 200. In this way, by avoiding useless Auth processing, the processing speed up until the power transmission begins can be improved.

[0136] <Processing of Power Transmission Devices>

[0137] Next, we will refer to Figure 6 The flowchart describes the following situation, in which the power transmitting device 100 according to this embodiment does not stop transmitting power even though device authentication has been performed through the second communication.

[0138] In step S601, the power transmitting device 100 sends an ACK for the OOB Req sent from the power receiving device 200 via the first communication unit 104. In response, by receiving the ACK, the power receiving device 200 begins to periodically send IDLE (step S406) and connects to the second communication unit 106 of the power transmitting device 100 using BLE (step S408).

[0139] In step S602, the power transmitting device 100 determines whether it has received an IDLE sent from the power receiving device 200 via the first communication unit 104. If an IDLE is received, the process proceeds to step S603. Otherwise, if an IDLE is not received, the process proceeds to step S605.

[0140] In step S603, the power transmitting device 100 extends the current digital Ping transmission for a predetermined period (e.g., 200ms). In step S604, the power transmitting device 100 determines whether a termination has been received from the second communication unit 202 of the power receiving device 200. If a termination is received, the process terminates. Otherwise, if no termination is received, the process returns to step S602.

[0141] Note that if Auth processing is in progress between the second communication unit 106 of the power transmitting device 100 and the second communication unit 202 of the power receiving device 200, the power transmitting device 100 does not receive termination from the second communication unit 202 of the power receiving device 200. Therefore, the process returns to step S602. Then, the power transmitting device 100 determines whether IDLE has been received again.

[0142] In step S605, the power transmitting device 100 determines whether a timeout has occurred. Here, the power transmitting device 100 sets a timeout value, for example, equal to or greater than 200ms (this value is the extended transmission period of the digital Ping set in step S603). If a timeout occurs, the process proceeds to step S606. On the other hand, if no timeout occurs, the process returns to step S602, and it again determines whether an IDLE has been received.

[0143] Here, power receiving device 200 may, for example, send the next IDLE within a maximum of 19ms from the end of the response packet (e.g., ACK) to IDLE. The process from the start of IDLE transmission by power receiving device 200, through the end of ACK transmission by power transmitting device 100 for IDLE, until the start of IDLE transmission by power receiving device 200 is considered as one cycle, and the duration of one cycle is set to, for example, 50ms. Then, power transmitting device 100 is always able to receive IDLE within 200ms (the extended transmission period of digital Ping), allowing power transmitting device 100 to extend the transmission period of digital Ping again.

[0144] Each time an IDLE is received, the power transmitter 100 resets the timer value to its initial value. This operation allows the power receiver 200 to send packets to the power transmitter 100 via the first communication, even while the power receiver 200 is authenticating with the power transmitter 100 via the second communication. Therefore, the power transmitter 100 can continue sending digital Pings without timeout. Furthermore, the power transmitter 100 can use the second communication unit 106 for higher-speed control communication while continuing control communication using the first communication unit 104.

[0145] If the power transmitting device 100 is unable to receive the IDLE packet due to reasons such as the power receiving device 200 having moved outside the power transmitting range of the power transmitting device 100, a timeout occurs ("Yes" in step S605). Therefore, in step S606, the power transmitting device 100 stops transmitting the digital Ping.

[0146] Then, in step S607, the power transmitting device 100 sends a termination message to the power receiving device 200 via the second communication unit 106. Through this operation, even if control communication using the first communication unit 104 of the power transmitting device 100 is disabled and power transmission stops, the power transmitting device 100 can also stop using the control of the second communication unit 106. Furthermore, if a termination message is received from the power receiving device 200 ("Yes" in step S604), the power transmitting device 100 can disconnect the BLE and terminate the process.

[0147] <Variant Example>

[0148] In the above embodiments, an example has been described in which, in order to prevent timeouts from occurring in the power transmitting device 200, the power receiving device 100 periodically sends IDLE packets via the first communication during the second communication.

[0149] At this time, during the second communication, the power transmitting device 100 can... Figure 6 The timeout value shown is set to a larger value than the case where only the first communication is performed.

[0150] After sending an ACK (F307) in response to the OOB Req (F306) and determining that a second communication has been initiated, the power transmitting device 100 sets a timeout value to a larger value compared to the case where only the first communication is performed (the case where no second communication is performed). Then, if a termination (F318) is received and it is determined that no second communication has been performed, the timeout value is reset to its original value. The larger value can be, for example, greater than 500 ms. Optionally, the timeout value can be a sufficiently large value to include the period from sending ADV (F309) or sending ACK (F307) to receiving the termination.

[0151] If the second communication is used, the power receiving device 200 sends IDLE at longer intervals compared to the case where only the first communication is performed, based on a timeout value set to a larger value. With this configuration, similar effects to those described in the above embodiment can be achieved.

[0152] Furthermore, if the second communication is used, the power transmitting device 100 can determine whether a timeout has occurred based on packets received via the second communication. If only the first communication is used, the power transmitting device 100 determines a timeout based on packets received via the first communication unit 104. On the other hand, after sending an ACK (F307) for the OOB Req (F306), the power transmitting device 100 determines a timeout based on packets received via the second communication unit 106. If the second communication is used, the timeout value can be changed.

[0153] To prevent timeouts in the power transmitting device 100, the power receiving device 200 transmits packets via the second communication unit 202. This configuration achieves effects similar to those described in the above embodiments.

[0154] Note that the power transmission method of the wireless power transmission system according to the present invention is not particularly limited. A magnetic field resonance method can be used, wherein power is transmitted by utilizing the coupling of magnetic field resonance (resonance) between a resonator (resonant element) of the power transmitting device and a resonator (resonant element) of the power receiving device. Alternatively, electromagnetic induction, electric field resonance, microwave, or power transmission methods using lasers, etc., can be used.

[0155] Each of the power transmitting and receiving devices can be, for example, an image input device such as a camera (camera, video camera, etc.) or a scanner, or an image output device such as a printer, copier, or projector. Optionally, each of the power transmitting and receiving devices can be a storage device such as a hard disk device or a memory device, or an information processing device such as a personal computer (PC) or a smartphone.

[0156] Start when the control unit is powered on. Figure 4A and Figure 4B , Figure 5A and Figure 5B as well as Figure 6 The flowcharts shown are shown below. Note that the process shown in Figure 4 is achieved by the control unit executing a program stored in the memory of the power receiving device. Figures 5 and... Figure 6 The processes shown in the diagram are implemented by the control unit executing programs stored in the memory of the power transmission device.

[0157] Notice, Figure 4A and Figure 4B , Figure 5A and Figure 5B as well as Figure 6 At least a portion of the processes shown in the flowcharts can be implemented in hardware. For example, if the processes are implemented in hardware, dedicated circuitry can be automatically generated on an FPGA based on the program used to implement each step using a pre-defined compiler. FPGA is an abbreviation for Field Programmable Gate Array. Alternatively, gate array circuitry can be formed as in the case of an FPGA and implemented as hardware.

[0158] (Other embodiments)

[0159] This invention can be implemented by providing a program for implementing one or more functions of the above embodiments to a system or device via a network or storage medium, and causing one or more processors in the computer of the system or device to read and execute the program. This invention can also be implemented by a circuit (e.g., an ASIC) for implementing one or more functions.

[0160] This invention is not limited to the above embodiments, and various changes and modifications can be made within the spirit and scope of this invention. Therefore, in order to inform the public of the scope of this invention, the following claims are made.

[0161] This application claims priority to Japanese Patent Application No. 2018-234711, filed on December 14, 2018, the entire contents of which are incorporated herein by reference.

Claims

1. A power receiving device, comprising: A power receiving unit configured to wirelessly receive power from a power transmitting device; as well as A communication unit configured to communicate with the power transmitting device. The communication unit transmits identification information of the power receiving device at a first frequency, sends information to the power transmitting device indicating whether authentication at a second frequency is available, and receives information from the power transmitting device indicating whether authentication at the second frequency is available.

2. The power receiving device according to claim 1, further comprising: An authentication unit is configured to perform authentication at the second frequency.

3. The power receiving device according to claim 1, wherein, The information indicating whether authentication is available at the second frequency is information indicating whether authentication is available through communication based on standards related to Bluetooth Low Energy.

4. The power receiving device according to claim 1, wherein, The authentication is conducted using a digital certificate.

5. A power transmission device, comprising: A power transmitting unit configured to wirelessly transmit power to a power receiving device; as well as A communication unit configured to communicate with the power receiving device. The communication unit receives the identification information of the power receiving device at a first frequency, receives information from the power receiving device indicating whether authentication at a second frequency is available, and sends information to the power receiving device indicating whether authentication at the second frequency is available.

6. The power transmission device according to claim 5, further comprising: An authentication unit is configured to perform authentication at the second frequency.

7. The power transmission device according to claim 5, wherein, The information indicating whether authentication is available at the second frequency is information indicating whether authentication is available through communication based on standards related to Bluetooth Low Energy.

8. The power transmission device according to claim 5, wherein, The authentication is conducted using a digital certificate.

9. A communication method for a power receiving device, the communication method comprising: The identification information of the power receiving device is transmitted at a first frequency; Send information to the power transmission device indicating whether authentication at the second frequency is available; as well as Receive information from the power transmitting device indicating whether authentication at the second frequency is available.

10. A storage medium storing a program for causing a computer to execute a communication method of a power receiving device, the communication method comprising: The identification information of the power receiving device is transmitted at a first frequency; Send information to the power transmission device indicating whether authentication at the second frequency is available; as well as Receive information from the power transmitting device indicating whether authentication at the second frequency is available.

11. A communication method for a power transmission device, the communication method comprising: The identification information of the power receiving device is received at the first frequency; Receive information from the power receiving device indicating whether authentication at the second frequency is available; as well as The power receiving device is sent information indicating whether authentication at the second frequency is available.

12. A storage medium storing a program for causing a computer to execute a communication method of a power transmission device, the communication method comprising: The identification information of the power receiving device is received at the first frequency; Receive information from the power receiving device indicating whether authentication at the second frequency is available; as well as The power receiving device is sent information indicating whether authentication at the second frequency is available.

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