Power receiving device and communication method

Abstract

To provide a power receiving device, program, and communication method that perform appropriate communication control in the power receiving device and a power transmitting device which can execute both in-band communication and out-band communication.SOLUTION: In a wireless power transmitting system, a first power receiving device RX1 that wirelessly receives power from a first power transmitting device TX1 communicates with the first power transmitting device at a second frequency when receiving a first packet from the first power transmitting device at a first frequency which indicates communication at the second frequency is possible, and transmits a packet indicating power transmission stop when receiving a packet indicating NAK from the first power transmitting device to a second packet transmitted at the first frequency.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] There has been widespread technological development of wireless power transmission systems including a power transmitting device and a power receiving device. Patent Document 1 describes a method for transmitting and receiving control signals in a power transmission system by so-called out-band communication, using a frequency, coil, and antenna different from those used for power transmission and reception.

[0003] In the standards (WPC standards) established by the Wireless Power Consortium (WPC), a standardization organization for wireless power transmission standards, power transmission and reception and the associated control communications are carried out using magnetic induction. Furthermore, power transmitters and receivers that comply with the current WPC standards perform control communications using the same frequency as that used for power transmission and reception. This control communication is so-called in-band communication, which is carried out via the coils used for power transmission and reception. Note that the range over which in-band communication can be performed without errors is narrower than that of out-band communication. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-217224 Summary of the Invention [Problem to be solved by the invention]

[0005] When considering a power transmitting device and a power receiving device that can perform both in-band communication and out-band communication, appropriate communication control in such a power transmitting device and a power receiving device has not been considered.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide an appropriate communication control technique for a power receiving device and a power transmitting device that are capable of performing both in-band communication and out-band communication. [Means for solving the problem]

[0007] A power receiving device according to one aspect of the present invention includes a power receiving means for wirelessly receiving power from a power transmitting device and a communication means for communicating with the power transmitting device, wherein the communication means communicates with the power transmitting device at the second frequency when it receives a first packet from the power transmitting device at a first frequency indicating that communication at a second frequency is possible, and the communication means transmits a packet indicating that power transmission is stopped when it receives a packet indicating NAK from the power transmitting device in response to the second packet transmitted at the first frequency. The communication means transmits identification information of the power receiving device. do. [Effects of the Invention]

[0008] According to the present invention, communication control can be appropriately performed in a power receiving device and a power transmitting device that are capable of performing both in-band communication and out-band communication. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram illustrating a configuration example of a wireless power transmission system. [Figure 2] FIG. 2 is a block diagram illustrating a configuration example of a power transmission device. [Figure 3] FIG. 2 is a block diagram illustrating a configuration example of a power receiving device. [Figure 4] 10 is a flowchart illustrating an example of a flow of processing by a power transmitting device. [Figure 5] 10 is a flowchart illustrating an example of a processing flow of a power receiving device. [Figure 6] FIG. 2 is an operation sequence diagram of the wireless power transmission system. [Figure 7] FIG. 10 is a diagram illustrating the configuration of a Configuration Packet. [Figure 8]FIG. 10 is a diagram illustrating the configuration of a Power Transmitter Capability Packet. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples and are not intended to limit the scope of the present invention. Various changes and modifications can be made within the scope of the technical concept of the present invention.

[0011] (System Configuration) FIG. 1 shows a wireless charging system according to this embodiment. The wireless charging system includes power transmitting devices (a first power transmitting device 101 and a second power transmitting device 102) and power receiving devices (a first power receiving device 111 and a second power receiving device 112). Hereinafter, the first power transmitting device 101 and the first power receiving device 111 may be referred to as "TX1" and "RX1," respectively. Similarly, the second power transmitting device 102 and the second power receiving device 112 may be referred to as "TX2" and "RX2," respectively. These power transmitting devices and power receiving devices each have a Bluetooth (registered trademark) Low Energy (BLE) communication function. Also, as an example, it is assumed that other devices (a first communication device 121 and a second communication device 122) that have a BLE communication function but do not have a wireless power transmission function are present around the wireless charging system. Hereinafter, a BLE communication unit (a unit including an antenna, a communication circuit, etc.) may be referred to as "BLE."

[0012] As shown in FIG. 1, TX1 and TX2 function as BLE Centrals, and RX1 and RX2 function as BLE Peripherals. The first communication device 121 functions as a Central, and the second communication device 122 functions as a Peripheral. Note that "Central" indicates a BLE control station, and "Peripheral" indicates a BLE terminal station. A BLE Central communicates with a BLE Peripheral, but does not communicate with other Centrals. A BLE Peripheral communicates with a BLE Central, but does not communicate with other Peripherals. In other words, in BLE, communication between Centrals or between Peripherals does not occur. A Central can be connected to multiple Peripherals (BLE CONNECT_State) and can transmit and receive data to and from multiple Peripherals. A Peripheral can be connected to only one Central, and does not communicate with multiple Centrals in parallel.

[0013] 1, it is assumed that RX1 is located within the power transmission and reception range from TX1, while RX2 is not located within the power transmission and reception range. Therefore, TX1 transmits wireless power only to RX1, but not to RX2.

[0014] In this case, in order for TX1 to perform control communication through outband communication using BLE and transmit power to RX1, the BLE (Central) of TX1 must be connected to at least the BLE (Peripheral) of RX1. As described above, the BLE Central can be connected to multiple Peripherals at the same time, so the BLE (Central) of TX1 may be connected not only to RX1 but also to RX2 functioning as a Peripheral or the second communication device 122. Similarly, the BLE (Central) of TX2 may be connected to RX1 or the second communication device 122 as long as it is connected to the BLE (Peripheral) of RX2.

[0015] On the other hand, the BLE (Peripheral) of RX1 can only be connected to one Central. Therefore, in order to perform control communication for power transmission between TX1 and RX1 via BLE, the BLE (Peripheral) of RX1 needs to be connected only to the BLE (Central) of TX1. This is because if the BLE (Peripheral) of RX1 is connected to another BLE (Central) such as Tx2 or the first communication device 121, it will not be able to perform control communication with the BLE (Central) of TX1. Similarly, in order to perform control communication for power transmission between TX2 and RX2 via BLE, the BLE (Peripheral) of RX2 needs to be connected only to the BLE (Central) of TX2. Therefore, the BLE (Peripheral) of RX2 should not be connected to other BLE (Central) such as Tx1 or the first communication device 121.

[0016] In this way, control communication should be performed between the power transmitting device and the power receiving device (e.g., TX1 and RX1) where power transmission and reception are performed. However, if the communication range of out-band communication is wider than the communication range of in-band communication, the power transmitting device and the power receiving device may establish a connection for out-band communication with a device that is not a target for power transmission and reception. Establishing such a connection for out-band communication with a device that is not a target for power transmission and reception is called a cross-connection. For example, in FIG. 1, a state in which RX1 and TX2 or the first communication device 121 are BLE connected is a cross-connection.

[0017] In FIG. 1, when TX1 uses BLE (outband communication) for control communication, it should not transmit power to charge the battery of RX1 or negotiate about power unless it is certain that a BLE connection has been established with RX1 that is within the power transmission and reception range. This is because if TX1 establishes a BLE connection with RX2 or the second communication device 122 to perform control communication while targeting RX1 as the power transmission target, the power transmission target (RX1) and the control communication partner device (RX2 or the second communication device 122) may differ. In this case, TX1 will not be able to perform appropriate control communication with RX1. Similarly, when RX1 uses BLE (outband communication) for control communication, it should not receive power from TX1 to charge the battery or negotiate about power unless it is certain that a BLE connection has been established with TX1 that is within the power transmission and reception range. This is because if RX1, with TX1 as the power receiving source, establishes a BLE connection with TX2 or the first communication device 121 to perform control communication, the power receiving source (TX1) and the other device of the control communication (TX2 or the first communication device 121) may be different. In this case, RX1 will not be able to perform appropriate control communication with TX1.

[0018] As described above, in the wireless power transmission system of FIG. 1 , it is important for both the power transmitting device and the power receiving device to confirm that control communication via BLE with a partner device within the power transmission / reception range is possible before transmitting / receiving power for charging the battery or negotiating that power. Therefore, in this embodiment, the power transmitting device and the power receiving device are configured to establish a connection via BLE with the partner device for wireless power transmission. Note that BLE is an example, and any wireless communication method available for out-of-band communication in wireless power transmission can be used. In the following, the wireless power transmission performed is assumed to comply with the WPC standard, which includes functions defined in version 1.2.2. In this embodiment, the power transmitting device and the power receiving device are described as complying with the WPC standard, but this is not limited thereto, and other wireless power transmission standards may also be used. Below, an example configuration of the power transmitting device and the power receiving device and an example of the processing flow executed are described.

[0019] (Device configuration) 2 is a block diagram showing an example of the configuration of a power transmitting device (e.g., TX1 and TX2). The power transmitting device includes, for example, a control unit 201, a power supply unit 202, a power transmitting unit 203, a first communication unit 204, a power transmitting coil 205, a second communication unit 206, and a memory 207.

[0020] The control unit 201 controls the entire power transmitting device. The control unit 201 includes, for example, one or more processors such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 201 may also include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like configured to execute the processes described below.

[0021] The power supply unit 202 is a power source that supplies power when at least the control unit 201 and the power transmission unit 203 operate. The power supply unit 202 can be, for example, a wired power receiving circuit that receives power from a commercial power source, a battery, or the like. The power transmission unit 203 generates an AC voltage and an AC current in the power transmission coil 205 in order to transmit power to the power receiving device via the power transmission coil 205. The power transmission unit 203 converts the DC voltage supplied by the power supply unit 202 into an AC voltage using, for example, a switching circuit with a half-bridge or full-bridge configuration using FETs. In this case, the power transmission unit 203 includes a gate driver that controls the ON / OFF of the FETs.

[0022] The first communication unit 204 performs control communication for wireless power transmission based on the WPC standard with a communication unit of the power receiving device (first communication unit 303 shown in FIG. 3). In this embodiment, the communication performed by the first communication unit 204 is so-called in-band communication (communication using the first method), in which the AC voltage or current generated by the power transmitting unit 203 is modulated and data to be communicated is superimposed on the wireless power. Furthermore, in this embodiment, when the power transmitting device uses only in-band communication for control communication, it is assumed that the power transmitting device can supply enough power to output a maximum of 15 watts of power to a charging unit of a power receiving device that also uses in-band communication.

[0023] The second communication unit 206 performs control communication for wireless power transmission based on the WPC standard with a communication unit of the power receiving device (second communication unit 304 shown in FIG. 3). The second communication unit 206 performs so-called out-band communication (communication by a second method) using a frequency different from the frequency of the power transmitting unit 203 and an antenna (not shown) different from the power transmitting coil 205. In this embodiment, the second communication unit 206 is assumed to be compatible with BLE, but instead, a communication unit compatible with another wireless communication method such as NFC or WiFi may be used.

[0024] In this embodiment, when out-band communication is used for control communication with a power receiving device, the power transmitting device can supply more power to the power receiving device than when in-band communication is used. For example, when control communication is performed via out-band communication, the power transmitting device can supply power such that a maximum of 100 watts is output to a charging unit of the power receiving device. In in-band communication, minute voltage and current changes are superimposed on the transmitted power for communication. In contrast, as the transmitted power increases, noise generated from the power transmitting unit and the power receiving unit increases. Therefore, when in-band communication is used, the transmitted power is limited so that the in-band communication unit can detect minute voltage and current changes required for communication. On the other hand, when out-band communication is used, such restrictions are eliminated, and the amount of transmitted power can be increased.

[0025] The memory 207 stores the state of each element of the power transmitting device and the wireless power transmission system, as well as the overall state.

[0026] 2, the control unit 201, power supply unit 202, power transmission unit 203, first communication unit 204, memory 207, and second communication unit 206 are each depicted as separate blocks, but two or more of these blocks may be integrated into one chip, etc. Also, one block may be divided into multiple blocks.

[0027] 3 is a block diagram showing an example of the configuration of a power receiving device (e.g., RX1 and RX2). The power receiving device includes, for example, a control unit 301, a power receiving unit 302, a first communication unit 303, a second communication unit 304, a power receiving coil 305, a charging unit 306, a battery 307, and a memory 308.

[0028] The control unit 301 controls the entire power receiving device. The control unit 301 includes, for example, one or more processors such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 301 may also include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like configured to execute the processes described below.

[0029] The power receiving unit 302 acquires the AC voltage and AC current generated in the power receiving coil 305 by power transmission from the power transmitting coil 205, and converts the received power into a DC voltage and DC current for operating the control unit 301, the charging unit 306, etc. The first communication unit 303 performs control communication for wireless power transmission based on the WPC standard with the first communication unit 204 of the power transmitting device. This control communication is performed by in-band communication (communication using a first method) that load modulates the electromagnetic waves received by the power receiving coil 305. In this embodiment, when only in-band communication is used for control communication with the power transmitting device, the power receiving device is capable of receiving power wirelessly from the power transmitting device and outputting a maximum of 15 watts of power to the charging unit 306.

[0030] The second communication unit 304 performs control communication for wireless power transmission based on the WPC standard with the second communication unit 206 of the power transmitting device. The second communication unit 304 performs out-of-band communication (communication using a second method) using a frequency different from the frequency of the electromagnetic waves received by the power receiving unit 302 and an antenna (not shown) different from the power receiving coil 305. In this embodiment, the second communication unit 304 is compatible with BLE. However, instead, a communication unit compatible with other wireless communication methods such as NFC or WiFi may be used. The second communication unit 304 may receive power from a battery 307, or may receive power directly from the power receiving unit 302 without going through the battery 307. In this embodiment, when out-of-band communication is used for control communication with the power transmitting device, the power receiving device is capable of receiving power wirelessly from the power transmitting device and outputting a maximum of 100 watts of power to the charging unit 306.

[0031] The charging unit 306 charges the battery 307 using the DC voltage and DC current supplied from the power receiving unit 302. The memory 308 stores the overall state and each element of the power receiving device and the wireless power transmission system.

[0032] 3, the control unit 301, the power receiving unit 302, the first communication unit 303, the second communication unit 304, the charging unit 306, and the memory 308 are each depicted as separate blocks, but two or more of these blocks may be integrated into one chip, etc. Also, one block may be divided into multiple blocks.

[0033] In the following, when a power transmitting device or a power receiving device supports control communication via out-of-band communication, it is referred to as being compliant with WPC standard version A. WPC standard version A is the successor to WPC v1.2.2, and includes at least the addition of control communication functionality via out-of-band communication.

[0034] (Processing flow) Next, an example of the flow of processing executed in each device will be described, and then an example of the flow of processing executed in the entire system will be described.

[0035] [Power transmission device operation] An example of the flow of processing executed by the power transmitting device (TX1) will be described below with reference to FIG. 4. This processing may be initiated when the power transmitting unit 203 is powered on and activated, for example, by receiving power from the power supply unit 202. This processing may also be implemented by the control unit 201 executing a program stored in the memory 207. However, this is not limiting, and this processing may also be executed when, for example, a user activates the power transmission function by pressing a predetermined button. At least a portion of the processing shown in FIG. 4 may be implemented by hardware. When at least a portion of the processing is implemented by hardware, for example, a dedicated circuit automatically generated on an FPGA using a predetermined compiler from a program for implementing the processing steps may be used. Similarly to an FPGA, the hardware for executing the predetermined processing steps may also be implemented by a gate array circuit.

[0036] When this process is initiated, TX1 starts processing in accordance with the WPC standard. In the WPC standard, the partner device is identified through a Selection phase (hereinafter referred to as the "Selection phase"), a Ping phase, and an Identification & Configuration phase (hereinafter referred to as the "I&C phase"). Then, in the Negotiation phase (hereinafter referred to as the "Negotiation phase"), negotiations regarding the transmission power are carried out, followed by a Calibration phase (hereinafter referred to as the "Calibration phase") for power transfer, followed by a Power Transfer phase (hereinafter referred to as the "PT phase") in which actual power transfer is carried out.

[0037] In FIG. 4, TX1 first executes the processes of the selection phase and the ping phase (S401). In the selection phase, TX1 transmits an analog ping via the transmitting coil 205. The analog ping is a minute amount of power for detecting an object present near the transmitting coil 205. TX1 detects the voltage or current value of the transmitting coil when transmitting the analog ping, and determines that an object is present nearby if the voltage is below a certain threshold or the current value exceeds a certain threshold, and then transitions to the ping phase. Then, in the ping phase, TX1 transmits a digital ping that is larger than the analog ping. Here, the digital ping has enough power to activate the control unit 301, the first communication unit 303, and the second communication unit 304 of RX1 that are present near the transmitting coil 205. When activated by a Digital Ping received via the receiving coil 305, the control unit 301 and first communication unit 303 of RX1 notify TX1 of the magnitude of the received voltage via in-band communication by the first communication unit 303. When TX1 receives notification of the received voltage value via the first communication unit 204, it ends the processing of the Ping phase and transitions to the I&C phase. In the I&C phase, TX1 receives an Identification Packet transmitted by RX1 (S402). At this time, TX1 may acquire information on whether RX1, the sender of the packet, complies with version A of the WPC standard, individual identification information of RX1 used in at least versions of the WPC standard earlier than version A, and identification information used in BLE. In one example, TX1 acquires the identification information used by RX1 in the WPC standard in the Identification Packet and checks whether the EXT bit, which indicates the presence of additional ID information, is set to "1." If the EXT bit is "1", TX1 acquires additional ID information from an Extended Identification Packet that is subsequently transmitted in accordance with the WPC standard. In this embodiment, this Extended Identification Packet stores an 8-byte Bluetooth Device Address that RX1 uses in BLE.In the following, the Bluetooth Device Address will be referred to as "BD_ADDR." BD_ADDR is a public address defined in the BLE standard that indicates, for example, the manufacturer of RX1 or individual identification information of the BLE communication function (second communication unit 304). At this point, TX1 can recognize that the identification information of RX1 used in the WPC standard corresponds to the identification information of BLE (that is, they relate to the same device).

[0038] TX1 also receives a Configuration Packet transmitted by RX1 in the I&C phase (S402). In this embodiment, a BLE bit indicating whether RX1, the sender of this packet, supports control communication using BLE is transmitted using one bit in the Configuration Packet. TX1, which complies with WPC Standard Version A, can determine whether RX1 has a control communication function using BLE by monitoring this bit. In this embodiment, another bit in the Configuration Packet is used to transmit a BLE Enable bit indicating whether RX1 can currently use BLE for control communication. The Configuration Packet has a configuration as shown in FIG. 7 , and the BLE bit / BLE Enable bit can be set in one of the reserved areas (areas 700, 701, and 702). At this time, if BLE control communication is supported, the area (bit) where the BLE bit is set is set to "1," and if BLE can be used for control communication, the area where the BLE Enable bit is set is set to "1." Since "0" is usually stored in the reserved area, a power receiving device compliant with a version earlier than WPC Standard Version A stores "0" in this area. This prevents the power transmitting device from mistakenly believing that a power receiving device that does not comply with version A of the WPC standard supports or can execute control communication via BLE. Note that these are merely examples, and the Configuration Packet does not necessarily need to include these elements. For example, since the BR_ADDR is transmitted by the Extended Identification Packet as described above, it is possible to determine that BLE communication is supported, and therefore the BLE bit may be omitted. In this case, if RX1 is not communicating with another device via BLE, for example, only the BLE Enable bit is transmitted, and TX1 can determine whether RX1 can execute control communication via BLE.Note that the BLE bit and BLE Enable bit are merely examples and may not be used. For example, it may indicate whether or not outband communication other than BLE is supported, and whether control communication via outband communication is executable when transmitting the Configuration Packet. Furthermore, for each communication method available for outband communication other than BLE, an area similar to the BLE bit and BLE Enable bit may be provided, indicating whether or not a communication function is available and whether or not control communication is executable. For example, an NFC bit indicating whether or not an NFC communication function is available may be provided.

[0039] Then, in response to receiving the configuration packet, TX1 transmits an acknowledgement (ACK) by in-band communication (S403). In response to transmitting the ACK, TX1 transitions to the negotiation phase.

[0040] Furthermore, by receiving the Configuration Packet, TX1 determines whether RX1 has a BLE control communication function and is in a state where BLE control communication can be performed with TX1 (S404). If RX1 does not have a BLE control communication function or is not in a state where BLE control communication can be performed with TX1 (NO in S404), TX1 determines not to use out-of-band communication because BLE control communication cannot be performed with RX1 (S420). In this case, TX1 performs in-band communication instead of out-of-band communication. Then, TX1 determines that the maximum allowable value of Guaranteed Power (GP) is 15 watts (W) (S421). Note that GP refers to the power value guaranteed by the power transmitting device with respect to the output power of the power receiving unit 302 to a load (e.g., a charging unit or a battery) even if the positional relationship between the power transmitting device and the power receiving device is shifted and the power transmission efficiency between the power transmitting coil 205 and the power receiving coil 305 decreases. TX1 determines the size of the GP that is allowed, and operates to reject any request for a GP that exceeds the allowed value in subsequent negotiations. After that, TX1 moves the process to S414.

[0041] On the other hand, if RX1 has a control communication function based on BLE and is capable of executing control communication based on BLE (YES in S404), TX1 determines whether or not there has been an inquiry about capability information from RX1 (S405). This inquiry about capability information is made by transmitting a General Request, which is data defined in the WPC standard, from RX1 to TX1. Note that such a General Request inquiring about capability information is hereinafter referred to as a "General Req (Capability)." If TX1 has not received a General Req (Capability) (NO in S405), it proceeds to S420 and determines not to use outband communication. On the other hand, if TX1 has received a General Req (Capability) (YES in S405), it transmits a Power Transmitter Capability Packet, defined in the WPC standard, to RX1. Hereinafter, the Power Transmitter Capability Packet will be referred to as a "TX Capability Packet." As shown in FIG. 8, the TX Capability Packet includes information about the capabilities of the power transmitting device, such as the maximum value of GP. In this embodiment, one bit of the reserved area of ​​the TX Capability Packet (area 800 and area 801 in FIG. 8) is further allocated as a BLE Enable bit. This BLE Enable bit has the same meaning as the BLE Enable bit in the Configuration Packet transmitted by RX1. Note that TX1 may also use one bit of the reserved area of ​​the TX Capability Packet as a BLE bit. This BLE bit also has the same meaning as the BLE bit in the Configuration Packet transmitted by RX1.

[0042] Prior to transmitting information in the TX Capability Packet, TX1 determines whether its own device is in a state where it can use BLE (S406). If its own device is not in a state where it can use BLE (NO in S406), TX1 sets the BLE Enable bit of the Tx Capability Packet to “0” and transmits the packet to RX1 (S419), and proceeds to S420. Meanwhile, TX1 determines whether it can currently perform control communication via BLE based on, for example, whether its own device is operating as a BLE Peripheral, whether BLE is being used with other devices, etc. For example, if TX1 is a Central, it can connect to multiple Peripherals, and therefore may determine that BLE is available for control communication. Furthermore, TX1 may determine that BLE is available for control communication when its own device is not communicating with other devices via BLE. On the other hand, if its own device is communicating with other devices as a Peripheral via BLE, TX1 may determine that BLE is not available for control communication. Alternatively, TX1 may make this determination through communication with a control unit of a product (such as a printer) connected to TX1. For example, the control unit 201 of TX1 may be connected to the control unit of the product via GPIO (General Purpose Input / Output) or serial communication, and the control unit 201 of TX1 may inquire about the usage status of BLE from the control unit of the product. In this case, if the response from the control unit of the product regarding the usage status of BLE indicates that BLE is in use, the control unit 201 of TX1 may determine that BLE cannot be used for control communication at that time. Alternatively, if the response indicates that BLE is not in use, the control unit 201 of TX1 may determine that BLE can be used for control communication.

[0043] Then, if TX1 is in a state where its own device can use BLE (YES in S406), it sets the BLE Enable bit of the Tx Capability Packet to "1" and transmits it to RX1 (S407). Then, TX1 determines that it is possible to communicate with RX1 using BLE at this point, and stores the BD_ADDR of RX1 acquired in S402 in memory (S408). Note that TX1 may store the BD_ADDR of RX1 in memory when it acquires it in S402, and discard the information when it determines that its own device cannot use BLE (NO in S406).

[0044] After the Tx Capability Packet with the BLE Enable bit set to "1" is transmitted in S407, TX1 may receive a signal from RX1 inquiring about BLE identification information of TX1. This signal may be, for example, a General Request in the WPC standard. Hereinafter, the General Request inquiring about BLE identification information is referred to as a "General Req (ID)." Upon receiving the General Req (ID), TX1 transmits a response to RX1 including a BD_ADDR for the BLE of its own device. This response may be a Power Transmitter Identification Packet (hereinafter referred to as a "TX ID Packet") defined in the WPC standard. The TX ID Packet includes the version of the WPC standard supported by the power transmitting device and an identification number, such as that of the manufacturer of the functional block related to in-band communication in the power transmitting device. Furthermore, a power transmitting device that supports version A can include a BLE BD_ADDR in this TX ID Packet. This allows RX1 to associate and recognize TX1's identification information in the WPC standard with the BLE identification information (BD_ADDR).

[0045] Following the processing of S408, TX1 activates its own device's BLE communication function as a scanner (S409) in order to attempt control communication with RX1 via BLE. Note that the scanner state is one of the states defined in the BLE standard, and receives a broadcasted ADVERTISE_INDICATION and discovers the BLE device (or service) that sent it. In the following, ADVERTISE_INDICATION will be referred to as ADV_IND. ADV_IND is a signal that is broadcast by a device in the advertiser state defined in the BLE standard, and is used to notify the device's BD_ADDR and supported service information.

[0046] After starting up as a scanner, TX1 waits for an ADV_IND to be transmitted (S410). If TX1 receives an ADV_IND for the BD_ADDR held in S408 (YES in S410 and S411) before a predetermined time has elapsed (while NO in S418), it transmits a connection request message via BLE to that BD_ADDR. That is, if TX1 receives an ADV_IND from RX1 before the timeout, it transmits a connection request message via BLE to RX1. This connection request message is CONNECT_REQ (hereinafter sometimes referred to as "CONNECT") defined in the BLE standard. Then, TX1 moves to the negotiation phase. Here, since communication via BLE is possible, negotiation in the negotiation phase is performed using BLE. At this point, TX1 is in a state where control communication via BLE (outband communication) can be performed, and therefore, TX1 determines that it can set GP sufficiently high. Therefore, TX1 sets the maximum allowable value of GP to, for example, 100 W (S413), and proceeds to S414. Note that TX1 may execute processing to determine the maximum allowable value of GP after an outband communication connection is actually established. In this case, even if TX1 has decided to use outband communication, if it is unable to actually establish an outband communication connection, it may proceed to S420.

[0047] Even if TX1 receives ADV_IND, it will not send CONNECT if the ADV_IND is not the ADV_IND of the BD_ADDR held in S408 (NO in S411). That is, when attempting control communication for power transmission, TX1 limits the target to which CONNECT is sent so as not to establish a BLE connection for a purpose other than such control communication. If a timeout occurs without receiving ADV_IND from RX1 (YES in S418), the process proceeds to S420.

[0048] In S414, TX1 negotiates GP with RX1. This negotiation is based on the maximum GP value that TX1 can tolerate and the GP value requested by RX1. Note that the maximum GP value that TX1 can tolerate is determined by the processing of S413 or S421, as described above, depending on whether outband communication is available. After that, TX1 performs processing in the calibration phase (S415), transitions to the PT phase (S416), and transmits power to RX1. In the PT phase, RX1 transmits control data to TX1 requesting an increase or decrease in transmitted power. Since this communication is control communication, it is performed via BLE (outband communication) when it is available. After that, when TX1 receives an End Power Transfer (EPT) from RX1 requesting the end of power transfer due to, for example, the end of charging (S417), it terminates the power transfer processing. Note that the transmission and reception of EPT is also control communication, so it is performed via BLE (outband communication) when it is available.

[0049] As described above, TX1 checks whether RX1 can perform control communication via BLE. TX1 also associates and recognizes RX1's WPC identification information with its BLE identification information, and transmits CONNECT when it receives ADV_IND including RX1's BLE identification information. This allows TX1 to establish a BLE connection with the target of power transmission, while preventing BLE connections from being established with other devices that are not the target of power transmission.

[0050] [Power receiving device operation] Next, an example of the flow of processing executed by the power receiving device (RX1) will be described with reference to FIG. 5 . This processing may be executed, for example, when the power receiving function is activated by a user pressing a predetermined button or when RX1 is brought close to TX1. This processing may also be started when the control unit 301 and the first communication unit 303 are activated by power received via the power receiving coil 305. This processing may be implemented by the control unit 301 executing a program stored in the memory 308, but dedicated hardware for executing the processing described below may also be used. For example, when at least a portion of the processing is implemented by hardware, a dedicated circuit may be automatically generated on an FPGA using a predetermined compiler from a program for implementing the processing steps. Similarly to an FPGA, the hardware for executing the processing steps may also be implemented by a gate array circuit.

[0051] 5, RX1 is first placed near TX1 and is detected by TX1, which then causes TX1 to transmit a Digital Ping. The control unit 301 and first communication unit 303 of RX1 are then activated by the Digital Ping received via the power receiving coil 305, and measure the magnitude of the received voltage of the Digital Ping. RX1 then notifies TX1 of the magnitude of the received voltage via in-band communication (S501). After that, RX1 transitions to the I&C phase.

[0052] In the I&C phase, RX1 transmits an Identification Packet to TX1 via in-band communication (S502). At this time, the Identification Packet includes information indicating whether or not version A of the WPC standard is supported, and individual identification information used in at least versions of the WPC standard earlier than version A. The individual identification information used in the WPC standard is identification information used when control communication is performed via in-band communication. RX1 can also transmit an Identification Packet by setting an EXT bit indicating whether or not additional ID information is present. If additional ID information is present, RX1 sets the EXT bit of the Identification Packet to "1" and transmits an Extended Identification Packet for transmitting the additional ID information. The Extended Identification Packet is also transmitted via in-band communication according to the WPC standard. In this embodiment, the 8-byte BD_ADDR used in BLE is transmitted via the Extended Identification Packet.

[0053] After transmitting the Identification Packet, RX1 transmits a Configuration Packet. At this time, RX1 first determines whether its own device is currently in a state where BLE can be used for control communication (S503). The determination of whether BLE can be used for control communication is made based on, for example, whether its own device is operating as a BLE Peripheral, whether BLE is being used with another device, etc. For example, when RX1 is a Central, it can connect to multiple Peripherals and therefore may determine that BLE can be used for control communication. Furthermore, RX1 may determine that BLE can be used for control communication when its own device is not communicating with another device via BLE. On the other hand, when its own device is communicating with another device as a Peripheral via BLE, RX1 may determine that BLE cannot be used for control communication. Furthermore, RX1 may make this determination by communicating with a control unit of a product (e.g., a smartphone, a camera, etc.) connected to RX1. For example, the control unit 301 of RX1 may be connected to the control unit of the product via GPIO (General Purpose Input / Output) or serial communication, and the control unit 301 of RX1 may inquire about the usage status of BLE from the control unit of the product. In this case, if the response from the control unit of the product regarding the usage status of BLE indicates that BLE is in use, the control unit 301 of RX1 may determine that BLE cannot be used for control communication at that time. Furthermore, if the response indicates that BLE is not in use, the control unit 301 of RX1 may determine that BLE can be used for control communication. Note that information indicating whether RX1 supports communication via BEL and whether BLE can be used for control communication may be transmitted using a reserved area in a configuration packet, as described above.

[0054] If RX1 cannot currently use BLE for control communication (NO in S503), it transmits a Configuration Packet with the BLE Enable bit set to "0" to TX1 via in-band communication (S520). Since RX1 cannot perform control communication with TX1 via BLE, it determines not to use out-band communication (S521). In this case, RX1 performs in-band communication instead of out-band communication. RX1 then determines that the maximum GP value it requests is 15 watts (W) (S522), and proceeds to S523.

[0055] On the other hand, if RX1 can currently use BLE for control communication (YES in S503), it transmits a Configuration Packet with the BLE Enable bit set to "1" to TX1 via in-band communication (S504). Then, RX1 waits for an ACK from TX1 (S505). If RX1 does not receive an ACK (NO in S505), it transitions to the PT phase (S525) and receives the power transmitted from TX1. Then, RX1 transmits an EPT to TX1 (S526) in response to a decision to terminate power transmission, for example, when charging of the battery 307 is completed, and terminates the process. Power transmitting devices that only support versions earlier than version 1.2 of the WPC standard do not support the negotiation phase and calibration phase. Therefore, when such a power transmitting device receives a Configuration Packet, it transitions to the PT phase without transmitting an ACK. Therefore, by transitioning to the PT phase when RX1 does not receive an ACK from TX1, RX1 can receive power even if TX1 is a power transmitting device of a version earlier than version 1.2 of the WPC standard. In other words, this configuration allows RX1 to ensure backward compatibility. Note that if ACK is not received, the maximum power that the power receiving unit 302 can supply to the load (the charging unit 306 and the battery 307) is limited to 5 watts.

[0056] If RX1 receives an ACK (YES in S505), it sends a General Req (Capability) inquiring about the capabilities of TX1 (S506) and waits for a response (TX Capability Packet) (S507). If it does not receive a TX Capability Packet (NO in S507), RX1 decides not to use outbound communication (S521) and executes the above-described processing from S522 onwards. If RX1 receives a TX Capability Packet (YES in S507), it checks the BLE bit and BLE Enable bit of the packet and determines whether TX1 can perform control communication via BLE (S508). If it determines that TX1 cannot perform control communication via BLE (NO in S508), the processing proceeds to S521.

[0057] If TX1 determines that it can perform control communication via BLE (YES in S508), RX1 transmits a General Req (ID) to acquire TX1's identification information in BLE (S509). Then, RX1 waits for a TX ID Packet from TX1 as a response to the General Req (ID) (S510). If no TX ID Packet is received from TX1 (NO in S510), RX1 determines not to use outband communication (S521) and executes the above-described processing from S522 onward. On the other hand, if RX1 receives a TX ID Packet from TX1 that conforms to version A of the WPC standard (YES in S510), it acquires TX1's BD_ADDR stored in the packet and stores it in memory 308 (S511). At this point, RX1 can recognize TX1's identification information in the WPC standard and the BLE BD_ADDR in association with each other. Then, in order to perform control communication with TX1 using BLE, RX1 activates itself as a BLE advertiser (S512) and broadcasts ADV_IND (S513). Note that the advertiser is one of the states defined in the BLE standard, and its role is to broadcast its own device's BD_ADDR and supported service information using ADV_IND so that the above-mentioned scanner can discover BLE devices (or services). Here, ADV_IND includes a UUID (Universally Unique IDentifier) ​​indicating a service (profile) supported by the second communication unit 304. Note that in this embodiment, a UUID indicating a wireless charging service using out-band communication according to the WPC standard (hereinafter referred to as "wireless charging service") is included in ADV_IND. In addition, ADV_IND may also include information such as the device type (e.g., camera, smartphone), manufacturer name, model name, and serial number of the product to which the power receiving device (RX1) is connected.

[0058] Thereafter, RX1 waits for a CONNECT to be transmitted from the Scanner that received the ADV_IND (S514). Then, when RX1 receives a CONNECT (YES in S514), it determines whether or not the identification information of the sender of the CONNECT is stored in the memory 308 as the identification information (BD_ADDR) of TX1 (S515). That is, RX1 determines whether or not the sender of the CONNECT is TX1. Here, if the sender of the CONNECT is not TX1 (NO in S515), RX1 transmits an LL_TERMINATE_IND to the device that sent the CONNECT, indicating that the BLE connection established by the CONNECT is to be terminated (S518). Note that LL_TERMINATE_IND will be referred to as "TERMINATE" below. If RX1 has not received CONNECT from TX1 (NO in S514 or S515), it repeatedly transmits ADV_IND (S513) until a predetermined time has elapsed since the start of transmission of ADV_IND and a timeout occurs (while NO in S519). If RX1 times out without receiving CONNECT from TX1 (YES in S519), it decides not to use outbound communication (S521) and executes the above-mentioned processing from S522 onwards.

[0059] On the other hand, when RX1 receives CONNECT from TX1 (YES in S514 and S515), it decides to use outband communication (S516) and determines that the maximum GP value requested is 100 watts (W) (S517). RX1 may perform the process of determining the requested GP value in response to the decision to use outband communication, or may perform this process after the outband communication connection is actually established. Even if RX1 decides to use outband communication in S516, if the outband communication connection cannot actually be established, it may proceed to S521. After that, RX1 proceeds to S523. In S523, RX1 negotiates GP with TX1. This negotiation is performed based on the maximum GP value allowable by TX1 and the GP value requested by RX1. The maximum GP value requested by RX1 is determined by the process of S517 or S522 depending on whether outband communication is available or not, as described above. After that, RX1 executes the process in the calibration phase (S524), and then transitions to the PT phase (S525), receiving power from TX1. In the PT phase, RX1 transmits control data to TX1 requesting an increase or decrease in the transmission power. Since this communication is control communication, it is performed via BLE (outband communication) when available. After that, for example, when charging is completed, RX1 transmits an EPT to TX1 via BLE (outband communication) requesting that power transmission for battery charging be stopped (S526). Then, RX1 transmits a TERMINATE to disconnect the BLE connection as necessary, and ends this process. Note that TX1 may transmit a TERMINATE after transmitting the EPT.

[0060] As described above, RX1 checks whether TX1 can perform control communication via BLE. Furthermore, RX1 associates and recognizes TX1's WPC identification information with its BLE identification information, and when RX1 receives a CONNECT that does not include TX1's BLE identification information, it disconnects the connection and accepts only CONNECT from TX1. This allows RX1 to establish a BLE connection with the target of power transmission, while preventing BLE connections from being established with other devices that are not the target of power transmission.

[0061] [Power transmission system processing flow] Next, an example of the flow of processing executed in the power transmission system will be described with reference to FIG. 6. First, in TX1, when the power transmitting unit 203 receives power from the power supply unit 202 and starts up, TX1 starts operating in accordance with the WPC standard. That is, first, in the selection phase, TX1 transmits an Analog Ping via the power transmitting coil 205 (M601). Then, as shown in FIG. 3, TX1 detects that RX1 is present in the vicinity of its own device (within the power transmitting and receiving range) through the Analog Ping, and transitions to the Ping phase. Then, in the Ping phase, TX1 transmits a Digital Ping (M602). When the control unit 301 and the first communication unit 303 of RX1 are activated by the Digital Ping received via the power receiving coil 305, RX1 notifies TX1 of the magnitude of the received power voltage through in-band communication by the first communication unit 303 (M603), and transitions to the I&C phase. When TX1 receives the notification of the received voltage value, it ends the processing of the Ping phase and moves to the I&C phase.

[0062] Next, RX1 transmits an Identification Packet to TX1 using the first communication unit 303 (M604). Here, RX1 notifies TX1 in the Identification Packet of information indicating that it supports version A of the WPC standard and individual identification information of RX1 used in at least versions of the WPC standard earlier than version A. In this processing example, RX1 transmits the Identification Packet with the EXT bit set to "1" in order to later transmit identification information used in BLE. Then, RX1 includes an 8-byte BD_ADDR used in BLE in an Extended ID Packet and transmits it by in-band communication (M605). Then, in this processing example, RX1 transmits a Configuration Packet in which the BLE bit is set to "1" indicating that the device itself supports control communication using BLE (M606). In addition, in this Configuration Packet, the BLE Enable Bit is set to "1".

[0063] TX1 sends an acknowledgement (ACK) via in-band communication in response to the configuration packet from RX1 (M607). After sending the ACK, TX1 transitions to the negotiation phase. Furthermore, upon receiving the ACK, RX1 ends the I&C phase and transitions to the negotiation phase. Note that at this point, TX1 can recognize that RX1's identification information in the WPC standard corresponds to the BD_ADDR in BLE. Furthermore, TX1 can recognize that RX1 is capable of control communication via BLE.

[0064] Thereafter, RX1 transmits a General Req (Capability) via in-band communication to acquire information about the capabilities of TX1 (M608). Upon receiving this General Req (Capability), TX1 transmits a TX Capability Packet to RX1 (M609). Here, TX1 transmits a TX Capability Packet that includes information that TX1 complies with version A of the WPC standard and sets the BLE bit / BLE Enable bit to "1" to indicate that it can perform control communication via BLE. At this time, upon receiving the TX Capability Packet, RX1 can recognize that TX1 supports control communication via BLE and that BLE can be used for control communication. Next, RX1 transmits a General Req (ID) via in-band communication to request the transmission of TX1's identification information (M610). Upon receiving this General Req (ID), TX1 transmits a TX ID Packet to RX1 via in-band communication (M611). At this point, RX1 can recognize that TX1's identification information in the WPC standard corresponds to the BD_ADDR in BLE, and that RX1 is capable of supporting control communication by BLE.

[0065] After that, RX1 activates its own BLE as an Advertiser to attempt control communication with TX1 via BLE and sends ADV_IND (M612). At this time, TX1 stores the BD_ADDR of RX1 acquired in M405 in memory, and activates its own device as a BLE Scanner to perform control communication with RX1 via BLE.

[0066] Here, it is assumed that not only TX1 but also another device (for example, the first communication device 121) is operating as a scanner. At this time, it is assumed that the other device receives the ADV_IND transmitted by RX1 in M612 and transmits CONNECT to RX1 to request a connection via BLE (M613). When RX1 receives this CONNECT, it refers to the memory 308 and determines whether the identification information of the source of the CONNECT matches the identification information (BD_ADDR) of TX1. In this case, since the other device is different from TX1, RX1 determines not to connect to this other device and transmits TERMINATE to this other device (M614).

[0067] On the other hand, when TX1 receives ADV_IND, it checks whether the ADV_IND contains a UUID indicating a wireless charging service. Here, as described above, ADV_IND contains a UUID corresponding to the wireless charging service. Then, TX1 subsequently refers to the memory 207 and determines whether the sender of ADV_IND matches the identification information (BD_ADDR) of RX1 stored in the memory 207. Because ADV_IND in M612 was sent from RX1, TX1 determines to connect to RX1, the sender of ADV_IND, and sends CONNECT to RX1 (M615). Then, because the sender of this CONNECT is TX1, RX1 does not send TERMINATE in this case and maintains the connection.

[0068] There is a case where TX2 receives ADV_IND transmitted by RX1. However, in this case, TX2 stores the BD_ADDR of RX2, which is present within the power transmission / reception range, in the memory 207, but does not store the BD_ADDR of RX1. Therefore, TX2 does not transmit CONNECT to RX1.

[0069] Thereafter, TX1 and RX1 negotiate GP using BLE (outband communication) (M616). At this point, TX1 can use BLE (outband communication) for control communication with RX1, which is within the power transmission and reception range, and therefore sets the maximum allowable GP value to 100 watts (W). Similarly, RX1 also sets the maximum requested GP value to 100 watts (W). TX1 and RX1 then negotiate to determine GP using these allowable GP values ​​and requested GP values. After that, after processing in the calibration phase is performed (M617), power is transmitted between TX1 and RX1 in the PT phase to charge the battery (M618). In the PT phase, RX1 transmits control data to TX1 requesting an increase or decrease in the transmitted power; in this example, this is performed using BLE (outband communication).

[0070] When charging is completed, RX1 transmits an EPT to TX1 via BLE (out-band communication) indicating a request to stop power transmission for battery charging (M619). When TX1 receives this EPT, it terminates power transmission for charging. Then, when this power transmission for charging is completed, RX1 transmits TEMINATE to TX1 and disconnects BLE (M620).

[0071] As described above, in this embodiment, the power transmitting device and the power receiving device use in-band communication to determine whether the other device supports out-band communication. Then, the power transmitting device and the power receiving device use in-band communication to acquire identification information used by the other device in out-band communication. Furthermore, when the power transmitting device receives AVD_IND via out-band communication, it determines whether to send CONNECT based on the identification information acquired via in-band communication. Furthermore, when the power receiving device receives CONNECT as a response to AVD_IND, it determines whether to send TERMINATE based on the identification information received via in-band communication.

[0072] This allows the power transmitting device and the power receiving device to perform control communication using BLE with the power receiving device and the power transmitting device within the power transmitting and receiving range before transmitting and receiving power to charge the battery or negotiating that power. By performing control communication using out-of-band communication in this way, it becomes possible to transmit and receive larger amounts of power than with in-band communication.

[0073] Furthermore, even if the other device supports BLE, the power transmitting device and the power receiving device determine to use in-band communication instead of out-band communication if BLE is not available (if the BLE Enable bit is "0") This allows the power transmitting device and the power receiving device to transmit and receive power using in-band communication when, for example, BLE is already being used by the control unit of the product to which the other device is connected.

[0074] In the above embodiment, when outband communication cannot be performed, the maximum allowable GP in the power transmitting device and the maximum GP required in the power receiving device are set to 15 watts. Also, when TX1 is a power transmitting device conforming to a version earlier than WPC standard version 1.2, the power supplied to the load in the power receiving device is limited to 5 watts. However, depending on the product connected to the power receiving device, 5 watts or 15 watts may be insufficient to operate the product. For example, this may be a product in which the load does not operate on battery power but receives power directly from the power receiving unit 302. In this case, supplying 5 watts or 15 watts of power may cause the product to malfunction. To avoid this situation, the power receiving device may transmit an EPT to the power transmitting device when it determines that outband communication cannot be used for control communication. This prevents insufficient power from being supplied via wireless power transmission, thereby preventing problems such as product malfunction.

[0075] On the other hand, it is also conceivable that the control unit of the product connected to RX1 controls the BLE (second communication unit 304) of RX1, and the second communication unit 304 operates on the power of the battery 307. In such a system, out-of-band communication cannot be performed if the remaining battery power is insufficient (for example, if the remaining battery power is 0). However, if the product operates on battery power and the remaining battery power is insufficient, the product will not operate, and the above-mentioned problems such as malfunction will not occur. For this reason, RX1 may receive power at 15 watts using in-band communication rather than transmitting EPT.

[0076] In the above-described embodiment, RX1 requests transmission of the BD_ADDR of TX1 by transmitting a General Req (ID), but this is not limited to this. For example, a reserved packet or proprietary packet with an undefined packet type among the specific requests of version 1.2.2 of the WPC standard may be used for this request. Also, a reserved packet or proprietary packet with an undefined packet type among the general requests of version 1.2.2 of the WPC standard may be used for this request. Also, a packet other than a specific request or general request among packets of version 1.2.2 of the WPC standard may be used for this request. For example, a reserved packet or proprietary packet with an undefined packet type other than a specific request or general request may be used for this request.

[0077] Also, it has been described that RX1 notifies TX1 that its own device supports BLE control communication using a configuration packet. However, this is not limited to this. For example, this notification may be made by a reserved packet or proprietary packet with an undefined packet type among the specific requests of version 1.2.2 of the WPC standard. Also, a reserved packet or proprietary packet with an undefined packet type among the general requests of version 1.2.2 of the WPC standard may be used for this notification. Also, a packet other than a specific request or general request among packets of version 1.2.2 of the WPC standard may be used for this notification. For example, a reserved packet or proprietary packet with an undefined packet type other than a specific request or general request may be used for this notification.

[0078] In the above description, the BD_ADDR is a public address defined in the BLE standard that indicates the individual identification information of the manufacturer of the power transmitting device or the power receiving device, or the BLE communication circuit (second communication unit), but this is not limited to this. For example, the BD_ADDR may be a random number automatically generated by the second communication unit, such as a random address defined in the BLE standard. Among these random addresses, any of a static device address, a resolvable private address, and a non-resolvable private address may be used. Here, the static device address is a random number address generated each time the second communication unit (BLE communication circuit) is powered on. The non-resolvable private address is a random number address generated at regular intervals. The resolvable private address is an address generated based on an encryption key exchanged between the central and the peripheral.

[0079] Also, it has been explained that RX1 transmits ADV_IND in M612 and transmits TERMINATE in response to CONNECT from a BLE-compatible device other than TX1 that transmitted a BD_ADDR in-band (for example, the first communication device 121 or TX2). Alternatively, in M612, ADV_DIRECT_IND, which is defined in the BLE standard and can directly specify the BD_ADDR of the BLE-compatible device that transmits CONNECT, may be transmitted. For example, RX1 transmits ADV_DIRECT_IND in M612 that stores the BD_ADDR of TX1. In this case, only TX1, which has been specified with a BD_ADDR, transmits CONNECT, and the first communication device 121 no longer transmits CONNECT. This simplifies the BLE connection process.

[0080] In the present embodiment, an example has been described in which the power receiving device is a Peripheral and the power transmitting device is a Central, as shown in FIG. 1 . However, the power receiving device may be a Central and the power transmitting device may be a Peripheral. That is, in the BLE-related processing described above, RX1 and TX1 may be interchanged. For example, TX1 may activate its own BLE as an Advertiser to attempt control communication with RX1 via BLE and transmit ADV_IND in M612. Then, RX1 may activate its own BLE as a Scanner to attempt control communication with TX1 via BLE and receive ADV_IND from TX1. If the identification information of the sender of the ADV_IND corresponds to the BD_ADDR of TX1 acquired by receiving the TX ID Packet in M611, RX1 may transmit CONNECT to TX1 in M615. TX1 establishes and maintains a BLE connection by CONNECT from RX1 based on the BD_ADDR of RX1 acquired by receiving the Extended ID Packet in M605. On the other hand, when TX1 receives CONNECT from a device other than RX1, it rejects the BLE connection by sending TERMINATE to disconnect the established BLE connection. Note that even in this case, TX1 may send ADV_DIRECT_IND in M612, storing the BD_ADDR of RX1 that it had previously received.

[0081] In the above description, TX1 or RX1 determines whether the remote device supports BLE or whether BLE is available using the BLE bit or BLE Enable bit. However, at least one of these determinations may be made based on a response to a packet transmitted by RX1 requesting a transition from in-band communication to out-band communication. RX1 may use a reserved packet or proprietary packet with an undefined packet type among the specific requests of version 1.2.2 of the WPC standard for this request during the negotiation phase. Alternatively, a reserved packet or proprietary packet with an undefined packet type among the general requests of version 1.2.2 of the WPC standard may be used for this request. Alternatively, a packet other than a specific request or general request among packets of version 1.2.2 of the WPC standard may be used for this request. For example, these packets may be used to newly define a packet requesting outband communication, and when RX1 receives an ACK from TX1 as a response to that packet, it may determine that TX1 supports BLE and can use BLE (YES in S508). Furthermore, when RX1 receives a NAK, which indicates a denial of the request, it may determine that TX1 does not support BLE or cannot use BLE, and may decide to use inband communication (S521). Furthermore, if TX1 does not support version A, TX1 transmits a No Data Response (ND Resp) packet or a Not Data Available packet indicating that it cannot understand this request. Therefore, when RX1 receives an ND Resp packet or a Not Data Available packet, it can determine that TX1 does not support outband communication and therefore to use inband communication (S521).

[0082] In the above embodiment, RX1 transmits the BD_ADDR using an Extended ID Packet. By using the Extended ID Packet already defined in the WPC standard to transmit the BD_ADDR, it is possible to use a packet that is already defined in version A without defining a new packet.

[0083] Furthermore, after transmitting and receiving the ACK in M607, TX1 and RX1 in version 1.2.2 transition to the negotiation phase and negotiate the GP. In contrast, in this embodiment, after performing the BLE connection process (M612, M615), TX1 and RX1 negotiate to determine whether to set the GP to 15 watts or 100 watts based on the results of the connection process. At this time, by determining the allowable GP for TX1 and the maximum GP required for RX1 prior to the negotiation based on the results of the BLE connection, it is possible to avoid the need for renegotiation due to an inappropriate GP being set. As a result, it is possible to reduce the time loss caused by such renegotiation. For example, if a decision is made to transmit 100 watts as a result of negotiation but a BLE connection cannot be established, renegotiation would be required with the maximum GP set to 15 watts. However, this can be avoided.

[0084] Although the above description has been given of an example in which wireless power transmission conforming to the WPC standard is used, the power transmission method is not particularly limited. For example, a magnetic resonance method may be used in which power is transmitted by coupling due to magnetic resonance between a TX resonator (resonant element) and an RX resonator (resonant element). Alternatively, a power transmission method using electromagnetic induction, electric field resonance, microwaves, lasers, etc. may also be used.

[0085] Although the above description uses specific terminology based on the WPC standard and the BLE standard, the present invention is not limited to this. That is, the present invention should be understood to include cases where messages having similar purposes are transmitted and received and similar processes are executed in systems having similar configurations. Furthermore, the above description describes that a specific message in the WPC standard or the BLE standard has a field for transmitting specific information, but the present invention is not limited to this. That is, a message different from the above description may be used to transmit the same information. For example, it has been described that information indicating whether RX1 is compatible with BLE and whether it is in a state where control communication via BLE can be performed is stored in a specific field in the configuration packet, but a new message for transmitting this information may be defined. The same applies to other messages.

[0086] The power transmitting device and the power receiving device may be included in an image input device such as an imaging device (such as a camera or a video camera) or a scanner, or an image output device such as a printer, a copier, a projector, etc. The power transmitting device and the power receiving device may be included in a storage device such as a hard disk device or a memory device, or may be included in an information processing device such as a personal computer (PC) or a smartphone.

[0087] <<Other embodiments>> The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0088] 101, 102: power transmitting device, 111, 112: power receiving device, 201: control unit, 202: power supply unit, 203: power transmitting unit, 204: first communication unit, 205: power transmitting coil, 206: second communication unit, 207: memory, 301: control unit, 302: power receiving unit, 303: first communication unit, 304: second communication unit, 305: power receiving coil, 306: charging unit, 307: battery, 308: memory

Claims

1. A power receiving device, power receiving means for wirelessly receiving power from a power transmitting device; a communication means for communicating with the power transmitting device, when the communication means receives, at a first frequency, a first packet from the power transmission device indicating that communication at a second frequency is possible, the communication means communicates with the power transmission device at the second frequency; the communication means transmits a packet indicating a power transmission stop when receiving a packet indicating a NAK from the power transmitting device in response to the second packet transmitted at the first frequency; The communication means transmits identification information of the power receiving device. Power receiving device.

2. The power receiving device according to claim 1 , wherein the first packet is a packet indicating a capability of the power transmitting device.

3. The power receiving device according to claim 1 or 2, wherein the second packet is a packet requesting communication at the second frequency.

4. A communication method executed by a power receiving device, comprising: a first communication step of communicating with the power transmitting device at the second frequency when a first packet indicating that communication at the second frequency is possible is received from the power transmitting device at the first frequency; a second communication step of transmitting a packet indicating a power transmission stop when a packet indicating a NAK is received from the power transmitting device in response to the second packet transmitted at the first frequency; a third communication step of transmitting identification information of the power receiving device; A communication method including:

Images