Power transmission device and method

Abstract

To make it possible for a power reception device that performs communication on the basis of NFC standards to receive power properly.SOLUTION: When a power receiving device 200 detected through communication with a first communication unit 104 and a device that performs communication based on NFC standards detected through communication with a second communication unit 106 are determined to be the same device, a control unit 101 controls a power transmission unit 103 to transmit power at a higher level compared to when they are different devices.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a power transmission device, a method performed by the power transmission device, and a program.

Background Art

[0002] In recent years, extensive research and development has been carried out on technologies for wireless power transmission systems such as contactless charging systems. In Patent Document 1, a power transmission device and a power reception device compliant with a standard (hereinafter referred to as the "WPC standard") established by the Wireless Power Consortium (WPC), a contactless charging standardization organization, are disclosed.

[0003] In addition, as a type of wireless communication method, there is the NFC (Near Field Communication) method. In the standard (specification) established by the NFC Forum, a card emulation mode is defined in which a battery-powered NFC module behaves as an NFC tag or an NFC card (hereinafter collectively referred to as an "NFC tag"). In addition, a reader / writer mode for reading NFC tags and a Peer to Peer mode for directly exchanging messages between NFCs are also defined. Some power reception devices such as smartphones compliant with the WPC standard also include an NFC module operating in these modes and perform communication based on the NFC standard.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] NFC tags do not have a battery and are driven using the energy of the electromagnetic wave transmitted during communication from the communication partner. If high-power wireless power transmission is performed from the power transmission device as described above to this NFC tag, there is a possibility that the antenna element etc. of the NFC tag will be damaged. In order to avoid such a situation, it is conceivable that the power transmission device restricts power transmission when detecting an object that performs communication based on the NFC standard. However, in such a configuration, the following problems occur. That is, when the power transmission device detects an object that performs communication based on the NFC standard, it is conceivable that the power transmission device restricts power transmission regardless of whether the object is an NFC tag or a power receiving device that performs communication based on the NFC standard. Therefore, if power transmission is restricted for a power receiving device that performs communication based on the NFC standard, it is conceivable that the received power amount will be insufficient.

[0006] An object of the present invention is to enable a power receiving device that performs communication based on the NFC standard to appropriately receive power.

Means for Solving the Problems

[0007] A power transmission device according to an aspect of the present invention includes power transmission means for wirelessly transmitting power to a power receiving device, Polling means for performing Polling using NFC communication, detection means for performing detection processing of an NFC tag, communication means for receiving identification information from the power receiving device, and negotiation means for negotiating with the power receiving device, and the negotiation means determines negotiable power based on the result of the detection processing.

Effects of the Invention

[0008] According to the present invention, a power receiving device that performs communication based on the NFC standard can appropriately receive power.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

Figure 9

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following embodiments are merely examples for explaining the technical idea of the present invention, and the present invention is not intended to be limited to the configurations and methods described in the embodiments.

[0011] (Configuration of the System) Fig. 9 shows a configuration example of the non-contact charging system (wireless power transmission system) according to the present embodiment. This system is configured to include a power transmission device 100 and a power receiving device 200. Hereinafter, the power transmission device may be referred to as TX, and the power receiving device may be referred to as RX. TX100 and RX200 comply with the WPC standard. RX200 receives power from TX100 and enables charging of the battery. TX100 is an electronic device that wirelessly transmits power to RX200 placed on its own charging stand. Hereinafter, the case where RX200 is placed on the charging stand will be described as an example. However, for TX100 to transmit power to RX200, RX200 does not have to be placed on the charging stand as long as it exists within the power transmission range of TX100 (the range indicated by the dashed line in Fig. 9).

[0012] In addition, RX200 and TX100 may have functions to execute applications other than non-contact charging. An example of RX200 is a smartphone, and an example of TX100 is an accessory device for charging the smartphone. RX200 and TX100 may be a tablet, a storage device such as a hard disk device or a memory device, or an information processing device such as a personal computer (PC). Also, RX200 and TX100 may be, for example, an imaging device (such as a camera or a video camera).

[0013] In addition, RX200 is equipped with a Near Field Communication (hereinafter referred to as "NFC") function, and using this function, for example, reading an NFC tag, electronic money settlement, etc. are possible. TX100 is also equipped with an NFC function to read an NFC tag. Therefore, TX100 can detect an NFC tag by performing communication based on the NFC standard. Furthermore, TX100 can stop or limit the power transmission process to protect the NFC tag based on the detection result.

[0014] This system performs wireless power transmission using an electromagnetic induction method for non-contact charging based on the WPC standard. That is, RX200 and TX100 perform wireless power transmission for non-contact charging based on the WPC standard between the power receiving antenna of RX200 and the power transmitting antenna of TX100. Note that the wireless power transmission method (non-contact power transmission method) applied to this system is not limited to the method defined by the WPC standard, and may be other electromagnetic induction methods, magnetic field resonance methods, electric field resonance methods, microwave methods, methods using lasers, etc. Also, in this embodiment, it is assumed that wireless power transmission is used for non-contact charging, but wireless power transmission may be performed for applications other than non-contact charging.

[0015] In the WPC standard, the amount of power guaranteed when RX200 receives power from TX100 is defined by a value called Guaranteed Power (hereinafter referred to as "GP"). GP indicates the power value that guarantees the output to the load of RX200 (for example, a circuit for charging, etc.), even if, for example, the positional relationship between RX200 and TX100 changes and the power transmission efficiency between the power receiving antenna and the power transmitting antenna decreases. For example, when GP is 5 watts, even if the positional relationship between the power receiving antenna and the power transmitting antenna changes and the power transmission efficiency decreases, TX100 controls the power transmission so that it can output 5 watts to the load in RX200.

[0016] RX200 and TX100 according to this embodiment perform communication for power transmission and reception control based on the WPC standard. In the WPC standard, a plurality of phases are defined, including a Power Transfer phase in which power transmission is executed and a phase before actual power transmission, and communication for power transmission and reception control required in each phase is performed. The phases before power transmission include a Selection phase, a Ping phase, an Identification and Configuration phase, a Negotiation phase, and a Calibration phase. Hereinafter, the Identification and Configuration phase will be referred to as the I&C phase.

[0017] In the Selection phase, TX100 intermittently transmits an Analog Ping to detect that an object is placed on the charging stand of TX100 (for example, RX200, a conductor piece, etc. are placed on the charging stand). TX100 detects at least one of the voltage value and the current value of the power transmitting antenna when transmitting the Analog Ping, and determines that an object exists when the voltage value is below a certain threshold or the current value exceeds a certain threshold, and then transitions to the Ping phase.

[0018] In the Ping phase, TX100 transmits a Digital Ping with greater power than the Analog Ping. The magnitude of the Digital Ping is sufficient power for the control unit of RX200 placed on the charging stand of TX100 to start up. RX200 notifies TX100 of the magnitude of the received power voltage. In this way, TX100 recognizes that the object detected in the Selection phase is RX200 by receiving the response from RX200 that has received its Digital Ping.

[0019] Upon receiving the notification of the received power voltage value, TX100 transitions to the I&C phase. In the I&C phase, TX100 identifies RX200 and acquires device configuration information (capability information) from RX200. Therefore, RX200 transmits an ID Packet and a Configuration Packet to TX100. The ID Packet contains the identifier information of RX200, and the Configuration Packet contains the device configuration information (capability information) of RX200. TX100 that has received the ID Packet and the Configuration Packet responds with an acknowledge (ACK, positive response). Then, the I&C phase ends.

[0020] In the Negotiation phase, the value of GP is determined based on the value of GP requested by RX200, the power transmission capability of TX100, etc.

[0021] In the Calibration phase, based on the WPC standard, RX200 notifies TX100 of the received power value, and TX100 performs adjustments for efficient power transmission.

[0022] In the Power Transfer phase, control is performed for starting power transmission, continuing it, and stopping power transmission due to errors or full charge, etc.

[0023] For these transmission and reception control operations, TX100 and RX200 perform communication (hereinafter referred to as "First Communication") that superimposes a signal on the electromagnetic wave transmitted from the antenna using the same antenna (coil) for wireless power transmission based on the WPC standard. Note that the range within which First Communication based on the WPC standard is possible between TX100 and RX200 is substantially the same as the power transmission range of TX100 (the range indicated by the dashed line in Fig. 9).

[0024] Note that TX100 and RX200 may perform the communication for these transmission and reception control operations using a different antenna and frequency from wireless power transmission (hereinafter referred to as "Second Communication"). For example, the electromagnetic wave used for Second Communication may have a higher frequency band than the electromagnetic wave used for First Communication. In this case, using Second Communication enables faster communication than when using First Communication.

[0025] As an example of Second Communication, a communication method compliant with the Bluetooth (registered trademark) Low Energy (hereinafter referred to as "BLE") standard can be cited. In this case, it is assumed that TX100 operates as a BLE Peripheral and RX200 operates as a BLE Central, but these BLE roles may be reversed. Also, Second Communication may be performed using other communication methods such as wireless LAN in the IEEE802.11 standard series (e.g., Wi-Fi (registered trademark)), ZigBee, etc. Note that when TX100 is capable of performing Second Communication and RX200 is within the power transmission range, RX200 and TX100 can exchange information via Second Communication.

[0026] (Device Configuration) Next, the configurations of the power transmission device 100 (TX100) and the power reception device 200 (RX200) according to this embodiment will be described. Note that the configurations described below are merely examples, and some (or in some cases, all) of the described configurations may be replaced with other configurations that perform similar functions or omitted, and additional configurations may be added to the described configurations. Furthermore, one block shown in the following description may be divided into a plurality of blocks, or a plurality of blocks may be integrated into one block.

[0027] FIG. 1 is a block diagram showing a configuration example of TX100 according to this embodiment. TX100 includes a control unit 101, a power supply unit 102, a power transmission unit 103, a first communication unit 104, a power transmission antenna 105, a second communication unit 106, and a memory 107. In FIG. 1, the control unit 101, the power supply unit 102, the power transmission unit 103, the first communication unit 104, the second communication unit 106, and the memory 107 are shown as separate entities, but any plurality of these blocks may be mounted within the same chip.

[0028] The control unit 101 controls the entire TX100 by executing, for example, a control program stored in the memory 107. Also, the control unit 101 performs control related to power transmission control including communication for device authentication in TX100. Furthermore, the control unit 101 may perform control for executing applications other than wireless power transmission. The control unit 101 includes, for example, one or more processors such as a (Central Processing Unit) or an MPU (MicroProcessor Unit). Note that the control unit 101 may be configured with hardware dedicated to specific processing such as an Application Specific Integrated Circuit (ASIC). Also, the control unit 101 may include an array circuit such as a Field Programmable Gate Array (FPGA) compiled to execute predetermined processing. The control unit 101 stores information to be stored during the execution of various processes in the memory 107. Also, the control unit 101 can measure time using a timer (not shown).

[0029] The power supply unit 102 supplies power to each block. The power supply unit 102 is, for example, a commercial power supply or a battery. Electric power supplied from the commercial power supply is stored in the battery.

[0030] The power transmission unit 103 converts the DC or AC power input from the power supply unit 102 into AC frequency power in a frequency band used for wireless power transmission, and generates an electromagnetic wave for causing the RX200 to receive power by inputting the AC frequency power to the power transmission antenna 105. For example, the power transmission unit 103 converts the DC voltage supplied by the power supply unit 102 into an AC voltage using a switching circuit having a half-bridge or full-bridge configuration using FETs (Field Effect Transistors). In this case, the power transmission unit 103 includes a gate driver that controls the ON / OFF of the FETs.

[0031] The power transmission unit 103 controls the intensity of the electromagnetic wave to be output by adjusting the voltage (transmission voltage) or current (transmission current), or both, input to the power transmission antenna 105. When the transmission voltage or transmission current is increased, the intensity of the electromagnetic wave becomes stronger, and when the transmission voltage or transmission current is decreased, the intensity of the electromagnetic wave becomes weaker. Also, the power transmission unit 103 performs output control of the AC frequency power so that power transmission from the power transmission antenna 105 is started or stopped based on an instruction from the control unit 101. Also, it is assumed that the power transmission unit 103 has the ability to supply power sufficient to output 15 watts of power to the charging unit of the RX200 compliant with the WPC standard.

[0032] The first communication unit 104 communicates with the RX200 for power transmission control based on the WPC standard as described above. The first communication unit 104 modulates the electromagnetic wave output from the power transmission antenna 105, transmits information to the RX200, and performs the first communication. Also, the first communication unit 104 demodulates the electromagnetic wave output from the power transmission antenna 105 and modulated at the RX200 to obtain the information transmitted by the RX200. That is, the first communication performed by the first communication unit 104 is performed with a signal superimposed on the electromagnetic wave transmitted from the power transmission antenna 105. Also, the first communication unit 104 may communicate with the RX200 using the second communication instead of the first communication, or may communicate with the RX200 by selectively using the first communication and the second communication. When the first communication unit 104 performs the second communication, the TX100 has an antenna different from the power transmission antenna 105.

[0033] The second communication unit 106 communicates with other NFC devices using the NFC function. It is assumed that the NFC devices in this embodiment include NFC tags unless otherwise specified. The second communication unit 106 enables the TX100 to detect the presence of an NFC tag. When an NFC tag is detected by the second communication unit 106, the control unit 101 controls the power transmission unit 103 to limit power transmission, such as stopping power transmission or reducing the power of power transmission. The second communication unit 106 has an antenna (not shown) different from the power transmission antenna 105.

[0034] Also, the second communication unit 106 is controlled by the control unit 101, but may be configured to be controlled by the control unit of another device (camera, smartphone, tablet PC, laptop) not shown that incorporates the TX100.

[0035] The memory 107 stores not only the control program but also the states of the TX100 and the RX200, etc.

[0036] FIG. 2 is a block diagram showing a configuration example of RX200 according to the present embodiment. RX200 includes a control unit 201, a second communication unit 202, a power receiving unit 203, a first communication unit 204, a power receiving antenna 205, a charging unit 206, a battery 207, and a memory 208. Note that a plurality of blocks shown in FIG. 2 may be realized as one hardware module.

[0037] The control unit 201 controls the entire RX200 by executing, for example, a control program stored in the memory 208. That is, the control unit 201 controls each functional unit shown in FIG. 2. Further, the control unit 201 may perform control for executing applications other than wireless power transmission. An example of the control unit 201 includes one or more processors such as a CPU or an MPU. Note that the entire smartphone may be controlled in cooperation with an OS (Operating System) executed by the control unit 201.

[0038] Further, the control unit 201 may be configured by hardware dedicated to specific processing such as an ASIC. Further, the control unit 201 may include an array circuit such as an FPGA compiled to execute predetermined processing. The control unit 201 stores information to be stored during execution of various processes in the memory 208. Further, the control unit 201 can measure time using a timer (not shown).

[0039] The second communication unit 202 performs communication processing with other communication devices using the NFC function. The second communication unit 202 operates, for example, in a mode compliant with the standards established by the NFC Forum. The above modes are, for example, a card emulation mode that substitutes for the role of a contactless IC card, a reader / writer mode for reading an NFC tag, and a P2P mode for directly exchanging messages between NFCs. For example, electronic money settlement and the like can be executed by the card emulation mode. Note that the P2P mode is an abbreviation for the Peer to Peer mode.

[0040] In order to perform communication based on the NFC standard, the second communication unit 202 has an antenna (not shown) different from the power receiving antenna 205. Further, the second communication unit 202 is controlled by the control unit 201, but may be configured to be controlled by a control unit of another device (camera, smartphone, tablet PC, laptop PC) not shown that incorporates RX200.

[0041] The power receiving unit 203 acquires, in the power receiving antenna 205, the alternating current power (alternating current voltage and alternating current) generated by electromagnetic induction caused by the electromagnetic wave radiated from the power transmitting antenna 105 of TX100. Then, the power receiving unit 203 converts the alternating current power into direct current or alternating current power of a predetermined frequency, and outputs the power to a charging unit 206 that performs processing for charging the battery 207. That is, the power receiving unit 203 supplies power to the load in RX200. The above-mentioned GP is the amount of power guaranteed to be output from the power receiving unit 203. It is assumed that the power receiving unit 203 has the ability to supply power for the charging unit 206 to charge the battery 207 and to supply power sufficient to output 15 watts of power to the charging unit 206.

[0042] The first communication unit 204 performs communication for power reception control based on the WPC standard as described above with the first communication unit 104 of TX100. The first communication unit 204 demodulates the electromagnetic wave input from the power receiving antenna 205 to acquire the information transmitted from TX100. Then, the first communication unit 204 performs first communication with TX100 by superimposing a signal related to the information to be transmitted to TX100 on the electromagnetic wave by load modulating the input electromagnetic wave. The first communication unit 204 may communicate with TX100 using second communication instead of the first communication, or may communicate with TX100 selectively using the first communication and the second communication. When the first communication unit 204 performs second communication, RX200 has an antenna different from the power receiving antenna 205.

[0043] In addition to storing the control program, the memory 208 also stores the states of TX100 and RX200 and the like.

[0044] Next, with reference to FIG. 3, a functional block diagram of the control unit 101 of the TX100 will be described. The control unit 101 includes a WPC processing unit 301 and an NFC processing unit 302. The WPC processing unit 301 is a processing unit that performs control communication for wireless power transmission based on the WPC standard via the first communication unit 104. Further, the WPC processing unit 301 controls the power transmission unit 103 and controls the power transmission to the RX200. The NFC processing unit 302 is a processing unit that performs communication related to the NFC standard via the second communication unit 106. The WPC processing unit 301 and the NFC processing unit 302 operate in parallel as independent programs, and their functions are implemented when the control unit 101 executes the program.

[0045] Next, with reference to FIGS. 4 and 5, the procedures of the processing performed by the NFC processing unit 302 and the WPC processing unit 301 in the TX100 will be described.

[0046] [Processing by NFC Processing Unit] FIG. 4 is a flowchart showing the processing operation of the NFC processing unit 302. This processing is continuously and repeatedly executed while the TX100 is activated.

[0047] When the TX100 is activated, the second communication unit 106 starts NFC Polling processing (S401). Specifically, the second communication unit 106 transmits a Polling request and monitors the response to monitor the proximity of other NFC devices. When an error is detected as a result of the Polling processing (Yes in S402), the NFC processing unit 302 notifies the WPC processing unit 301 that an error has occurred in the NFC processing (S403). The error here means a failure in communication related to the NFC standard, and does not include the absence of a response to the Polling request, that is, the non-existence of the communication partner NFC device. An example of an error is a so-called collision error in which response data cannot be received normally when a plurality of other NFC devices existing within the communication range related to the NFC standard respond at the same timing.

[0048] When such an error occurs, NFC cannot be performed properly with other NFC devices within the communication range, so it is impossible to confirm whether the detected NFC device includes a battery-less NFC tag. Therefore, the NFC processing unit 302 notifies the WPC processing unit 301 of the possibility that an NFC tag is close, and the WPC processing unit 301 that has received this suppresses power transmission processing at high power, thereby reducing the possibility of damaging the NFC tag.

[0049] If an error is not detected as a result of the Polling process (No in S402), the NFC processing unit 302 notifies the WPC processing unit 301 that there is no error in the NFC process (S404). Even when the error is resolved, the NFC processing unit 302 notifies that there is no error in the NFC process.

[0050] Next, the NFC processing unit 302 determines whether there is a specific response to the Polling request transmitted in S401 (S405). The specific response is a response indicating that the device does not support the P2P mode. If there is no specific response (No in S405), the NFC processing unit 302 notifies the WPC processing unit 301 that there is no specific NFC device around (S406). Also, it may be configured to notify that there is no specific NFC device around only when there is no such specific response continuously for a plurality of Polling requests.

[0051] Note that the specific NFC device is an NFC tag, a device that does not support the P2P mode, or a device that supports the P2P mode but is operating in the reader / writer mode. Note that a device operating in the reader / writer mode does not respond to a Polling request regardless of whether it supports the P2P mode. Therefore, the NFC processing unit 302 cannot detect a device operating in the reader / writer mode, and if only a device operating in the reader / writer mode is placed on the charging stand, it is determined as No in S405.

[0052] In addition, the case of no specific response is as follows. That is, when there is no device for communicating regarding the NFC standard, when there is an NFC device but it does not respond to a Polling request, or when it responds to a Polling request but the device supports the P2P mode. The case where the device supports the P2P mode means that the NFC device can operate in the P2P mode. For example, even if the NFC device is operating in the card emulation mode, if it supports the P2P mode, it is said to support the P2P mode. Note that when the device supports the P2P mode, the response data to the Polling request includes information indicating that the P2P mode is supported. Therefore, the NFC processing unit 302 can determine whether the detected NFC device supports the P2P mode based on the response data.

[0053] On the other hand, when there is a specific response (Yes in S405), the NFC processing unit 302 repeats the processing of S407 to S411 for the number of received responses. For each of the received response data, the NFC processing unit 302 acquires the identifier information of each NFC device included in each data (hereinafter sometimes referred to as "NFC identifier information") (S408). Here, regardless of whether the response to the Polling request is a specific response or not, the NFC identifier information of the NFC device that has responded is acquired. Note that the NFC processing unit 302 can detect the presence of an NFC device in the vicinity based on the presence or absence of a response.

[0054] The NFC identifier information is identifier information that can uniquely identify other NFC devices existing within the NFC communication range. In the present embodiment, it is IDm data used in the FeliCa (registered trademark) technology. In the NFC standard, an area called IDm is defined as the format of communication data, and the content of the data specified in the IDm area is defined by the FeliCa standard. Therefore, in the present embodiment, the IDm data used in the FeliCa technology is used. However, the NFC identifier information is not limited to this as will be described later.

[0055] When the acquisition of the NFC identifier information is successful (Yes in S409), the NFC processing unit 302 notifies the acquired NFC identifier information to the WPC processing unit 301 (S410). When the acquisition of the NFC identifier information fails (No in S409), the NFC processing unit 302 notifies the WPC processing unit 301 that an error has occurred in the NFC processing (S411).

[0056] After performing the identifier acquisition process (S408 to 411) of the NFC device included in all the response data, the NFC processing unit 302 compares the NFC identifier information acquired in the previous NFC processing with the NFC identifier information acquired in the current NFC processing. As a result of the comparison, if there is NFC identifier information that could not be acquired this time among the NFC identifier information acquired previously (Yes in S412), the NFC processing unit 302 notifies the WPC processing unit 301 that the NFC identifier information has disappeared and the NFC identifier information (S413). Also, if the identifier acquisition failed in the previous Polling process and the identifier acquisition did not fail in the current Polling process, the NFC processing unit 302 notifies the WPC processing unit 301 that the error in the NFC processing has been resolved.

[0057] Note that although the NFC processing unit 302 sequentially notifies the WPC processing unit 301 of the error status of the NFC processing and the acquired NFC identifier information, this NFC processing is not limited to this. The notification to the WPC processing unit 301 may be made to the WPC processing unit 301 collectively after all the processes are performed. The notification to the WPC processing unit 301 includes a notification of error occurrence (S402), a notification of non-detection of response data (S405), a notification of the acquired NFC identifier information (S410), and a notification of failure in the acquisition of the NFC identifier information (S411). Also, the acquired NFC identifier information may be listed and the list may be notified to the WPC processing unit 301.

[0058] [Processing by the WPC Processing Unit] FIG. 5 is a flowchart showing the processing operation of the WPC processing unit 301. This processing is also continuously and repeatedly executed while TX100 is activated.

[0059] When TX100 is activated, the WPC processing unit 301 performs Selection phase processing (S501). Specifically, it transmits an Analog Ping via the power transmission unit 103 and the power transmission antenna 105. TX100 detects at least one of the voltage value and the current value of the power transmission antenna 105 when transmitting the Analog Ping. When the voltage falls below a certain threshold or the current value exceeds a certain threshold, etc., TX100 determines that there is an object around the power transmission antenna 105 and transitions to the Ping phase.

[0060] In the Ping phase processing of S502, TX100 transmits a Digital Ping larger than the Analog Ping. The magnitude of the Digital Ping is sufficient power for at least the control unit 201 of the RX200 existing in the vicinity of the power transmission antenna 105 to be activated. Subsequently, when receiving a received power voltage notification notifying the magnitude of the received power voltage from the RX200, TX100 transitions to the I&C phase. By receiving this received power voltage notification via the first communication unit 104, TX100 can recognize that the object placed on the charging stand is the RX200.

[0061] In the I&C phase, TX100 receives an ID Packet transmitted from the RX200 (S503). Also, TX100 refers to the information bit (Ext bit) included in the ID Packet and determines whether additional identifier information is transmitted from the RX200 (S504).

[0062] If the Ext bit is 1 (Yes in S504), TX100 determines that additional identifier information is to be transmitted, waits for the Extended Identification Packet sent from RX200, and receives that packet (S505). That packet contains the Extended Device Identifier of RX200, which is up to 8 octets. TX100 stores this additional identifier information in the memory 107 as NFC identifier information (S506). That is, this additional identifier information is stored in the memory 107 as NFC identifier information obtained in the NFC process, unlike the identifier information contained in the ID Packet.

[0063] Subsequently, TX100 receives the Configuration Packet sent from RX200 (S507). TX100 refers to the information bit (Neg bit) contained in this packet and determines whether to transition to the Negotiation phase (S508).

[0064] In the Negotiation phase, TX100 negotiates with RX200 to determine the above-mentioned GP. If the Neg bit is 0 (No in S508), TX100 sends an ACK Packet to RX200 (S509). At this time, TX100 does not transition to the Negotiation phase but shifts to the Power Transfer phase (S510) and performs power transmission processing for RX200 with low power. The low power here is the power output value determined such that even if TX100 performs power transmission processing, it will not damage the NFC tag. This low power may be, for example, an arbitrarily set value, or a value set based on at least one of the power, current, and voltage defined by the WPC standard or other standards.

[0065] When the Neg bit is 1 (Yes in S508), TX100 transmits an ACKPacket to RX200 (S511) and transitions to the Negotiation phase. In the processing during the Negotiation phase (S512~S524), TX100 waits for a Specific Request Packet or a General Request Packet transmitted from RX200.

[0066] When TX100 receives a Specitic Request Packet (Yes in S512), it determines whether it can permit the value of the GP specified in this packet (S513~S518). The Specitic Request Packet contains values that are candidates for the power (GP) requested by RX200. TX100 first determines whether the specified GP value is less than or equal to a pre-set threshold (S513). The threshold here is the threshold of the power transmission output that is determined not to damage the NFC tag even if power transmission processing is performed. If the specified GP value is less than or equal to the threshold (No in S513), TX100 permits the specified GP value and transmits an ACK Packet to RX200 (S517).

[0067] If the specified GP value is greater than or equal to the threshold (Yes in S513), TX100 determines whether an error has occurred in the NFC processing (S514). Specifically, it is determined whether the WPC processing unit 301 has been notified of the occurrence of an error from the NFC processing unit 302 (S413, S411 in FIG. 4). If an error has occurred in the NFC processing (Yes in S514), there may be an NFC tag within the communication range of TX100. Therefore, TX100 rejects the requested GP value that is greater than or equal to the threshold and transmits a NAK Packet to RX200 (S518). After that, TX100 continues to wait for a Specific Request Packet or a General Request Packet.

[0068] For example, when no error has occurred in the NFC process (No in S514), TX100 determines whether there is an NFC device that has made a specific response to the Polling request (S515). Specifically, the WPC processing unit 301 makes this determination based on whether it has been notified by the NFC processing unit 302 that there is no specific NFC device (S406 in FIG. 4).

[0069] When there is no specific NFC device that has responded to the Polling request (No in S515), TX100 permits the specified GP value and transmits an ACKPacket to RX200 (S517).

[0070] When there is a specific NFC device that has responded to the Polling request (Yes in S515), TX100 determines whether the NFC device detected in the NFC process and the RX200 detected in the WPC process are the same device. Specifically, the WPC processing unit 301 compares the NFC identifier information notified by the NFC processing unit 302 with the additional identifier information stored in the process of S506, and determines whether these identifier information match (S516). When the identifier information matches, the WPC processing unit 301 determines that the NFC device detected in the NFC process and the RX200 detected in the WPC process are the same device.

[0071] When it is determined that they are the same device (Yes in S516), TX100 permits the specified GP value and transmits an ACK Packet to RX200 (S517). In this case, TX100 determines that RX200 has a power source for executing the WPC communication process and that some power supply is provided to the module that executes the NFC function of RX200. Therefore, even if TX100 performs a power transmission process with an output equal to or higher than the threshold value, it determines that no damage will be caused to the NFC device detected by the NFC processing unit 302, and permits the GP value specified from the RX.

[0072] If the NFC device detected in the NFC process and the RX200 detected in the WPC process are not the same (No in S516), the TX100 rejects the value of the requested GP that is equal to or greater than the threshold and transmits a NAK Packet to the RX200 (S518). Since the NFC tag is not the RX200, the WPC process as shown in FIG. 5 is not executed, and the NFC identifier information is not transmitted to the TX100. Therefore, it is determined that the NFC device detected in the NFC process and the RX200 detected in the WPC process are not the same. Thereafter, the TX100 continues to wait for a Specific Request Packet or a General Request Packet.

[0073] In addition, if there are multiple pieces of NFC identifier information notified from the NFC processing unit 302, and the corresponding additional identifier information is not stored for all the NFC identifier information in the process of S506, a NAK Packet is transmitted to the RX200 (S518). That is, when there is an NFC identifier among the multiple identifiers notified from the NFC processing unit 302 for which the corresponding additional identifier information is not stored in S506, a NAK Packet is transmitted to the power receiving device 200. On the other hand, when the corresponding additional identifier information is stored for all the NFC identifier information notified from the NFC processing unit 302 in the process of S506, an ACK Packet is transmitted to the RX200 (S517).

[0074] Next, the case where the TX100 receives a General Request Packet will be described. The TX100 receives a packet that requests to notify the capabilities (Power Transmitter capabity) of the TX100 among the General Request Packets (No in S512, Yes in S519). In this case, in the response packet of this packet, a determination process for determining the value of GP to be notified to the RX200 is performed (S520 to S524).

[0075] TX100 first determines whether an error has occurred in the NFC process (S520). The determination method is the same as the process of S514. If an error has occurred in the NFC process (Yes in S520), TX100 responds with the power transmission output value that can be determined not to damage the NFC tag even if power transmission processing is performed as the GP value (S524). Here, it responds with GP = 0.5 watt. Note that the value of this GP is not limited to 0.5 watt, and any power value that does not damage the NFC tag may be used. Also, the value of this GP may be 0 watt, or it may be notified that power transmission is not performed.

[0076] If no error has occurred in the NFC process (No in S520), TX100 determines the presence or absence of a specific NFC device that has responded to the Polling request (S521). The determination method is the same as the process of S515. If a specific NFC device that has responded to the Polling request does not exist (No in S521), TX100 responds with the maximum power transmission output value defined in the WPC standard among the capabilities of the power transmission unit 103 as the GP value (S523). Here, it responds with GP = 15 watts. This value of GP is an example and is not limited to this.

[0077] If a specific NFC device that has responded to the Polling request exists (Yes in S521), TX100 determines whether the NFC device detected in the NFC process and the RX200 detected in the WPC process are the same device (S522). The determination method is the same as the process of S516.

[0078] If it is determined that the devices are the same (Yes in S522), TX100 responds with the maximum power transmission output value defined in the WPC standard among the capabilities of the power transmission unit 103 as GP (S523). On the other hand, if it is determined that the devices are not the same (No in S516), TX100 responds with a power transmission output value that can be determined not to damage the NFC tag even if power transmission processing is performed as GP (S524). That is, when it is determined that the devices are the same, TX100 sets a larger GP than when it is determined that the devices are not the same, and performs power transmission based on this GP.

[0079] When TX100 receives a Specific Request Packet requesting the end of the Negotiation phase from RX200, it transitions to the Calibration phase (S525). In the Calibration phase, parameters necessary for the foreign object detection function for TX100 to detect the presence of an object other than RX200 in the vicinity of the power reception antenna 205 are determined. TX100 adjusts the power transmission output so that RX200 can be charged with the GP promised in S517, or the GP responded in S523 or S524.

[0080] Thereafter, TX100 transitions to the Power Transfer phase (S526) and supplies power to the charging unit 206 of RX200. TX100 continues the power transmission process until it receives an End Power Transfer Packet from RX200.

[0081] [WPC Processing in RX] Next, with reference to FIG. 8, the operation procedure of WPC processing in RX200 is shown. This process is repeatedly executed while the setting for executing the charging function by WPC is set in RX200.

[0082] When the control unit 201 of RX200 receives the Digital Ping transmitted from TX100 (Yes in S801), it detects the presence of TX100 nearby (S802). In response to this, the control unit 201 acquires the NFC setting / operation information in the second communication unit 202 (S803). The setting / operation information referred to here includes the state indicating whether the NFC function in RX200 is enabled or disabled, the operation mode of NFC, and the NFC identifier information that can be uniquely identified as an NFC device. Also, the operation mode of NFC referred to here represents the operation mode of NFC in the second communication unit 202, and represents any one of the three modes: card emulation mode, reader / writer mode, and P2P mode. Subsequently, the control unit 201 notifies TX100 of the received power voltage of the Digital Ping using a Signal Strength Packet via the first communication unit 204 (S804).

[0083] Next, the control unit 201 selects the next packet to be transmitted according to the NFC communication setting / operation information acquired in S803. Specifically, when the NFC function is enabled and the operation mode of NFC is the card emulation mode (Yes in S805), the control unit 201 transmits an ID Packet to TX100 (S807). In the ID Packet to be transmitted here, set 1 in the Ext bit, and then notify TX100 that an Extended Identification Packet will be transmitted.

[0084] Subsequently, the control unit 201 sets the NFC identifier information acquired in S803 in the Extended Identification Packet and transmits it to TX100 (S808).

[0085] Also, when the NFC function is disabled, or when the NFC function is enabled but the operation mode is other than the card emulation mode (No in S805), the control unit 201 does not transmit an Extended Identification Packet. That is, it transmits an Identification Packet with 0 set in the Ext bit to TX100 (S806). By thus determining whether to transmit a Packet according to the operation state of the NFC function in RX200, it becomes possible to suppress unnecessary communication. Thereby, it becomes possible to reduce the power consumption in both TX100 and RX200.

[0086] Next, the control unit 201 transmits a Configuration Packet to TX100 (S809) and requests TX100 to transition to the Negotiation phase for negotiating to determine the GP. When RX200 receives an ACK Packet from TX100 (Yes in S810), it transitions to the Negotiation phase. If it cannot receive an ACK Packet within a certain time (No in S810), RX200 transitions to the Selection phase and returns the processing state to the standby process for Digital Ping.

[0087] When transitioning to the Negotiation phase, the control unit 201 transmits a Specific Request Packet designating 15 watts as a candidate for the GP to TX100 (S811). When RX200 receives an ACK Packet from TX100 (Yes in S812), it determines that a GP of 15 watts is permitted in TX100, and the GP in the power reception process is determined to be 15 watts (S813).

[0088] Also, when RX200 receives a NAK Packet from TX100 (No in S812, Yes in S814), it determines that the 15-watt GP has been rejected at TX100. In that case, RX200 sends a General Request Packet to TX100 (S815) and requests the GP candidates at TX100. When RX200 receives a Power Transmitter Capability Packet from TX100 (S816), the value of the GP candidate of TX100 included in this packet is determined as the GP in this charging process (S817).

[0089] Also, if neither an ACK Packet nor a NAK Packet is received (No in S814), RX200 transitions to the Selection phase and returns the processing state to the waiting process for Digital Ping.

[0090] When the negotiation of GP is completed, TX100 and RX200 transition to the Calibration phase (S818). In the Calibration phase, TX100 determines the parameters necessary for the foreign object detection function to detect the presence of an object other than RX200 in the vicinity of the power receiving antenna 205. Also, in the Calibration phase, RX200 also performs the process of supplying power from the power receiving unit 203 to the charging unit 206 serving as a load.

[0091] After that, TX100 and RX200 transition to the Power Transfer phase, and RX200 charges the battery 207 (S819). When the charging is completed (Yes in S820), RX200 sends an End Power Transfer Packet to TX100 (S821) to notify TX100 of the end of the charging process.

[0092] [Sequence of Wireless Power Transmission System] Next, with reference to FIG. 6, the sequence of the wireless power transmission system including TX100 and RX200 will be described. FIG. 6 shows an example of the communication sequence between TX100 and RX200 when RX200 is brought close to TX100.

[0093] First, it is assumed that RX200 operates the NFC function by the second communication unit 202 in the card emulation mode (S601).

[0094] On the other hand, the NFC processing unit 302 of TX100 periodically performs the Polling process according to the NFC standard (S602). When RX200 comes close within the NFC communication range, a response to the Polling request is made, and the NFC processing unit 302 detects that an NFC device has come close (S603). The NFC processing unit 302 reads the NFC identifier information from the Polling response and notifies the WPC processing unit 301 (S604).

[0095] Also, the WPC processing unit 301 of TX100 periodically transmits an Analog Ping (S605), and if it determines that there is an object in the vicinity of the power transmission antenna 105, it transmits a Digital Ping (S606).

[0096] RX200 detects TX100 by receiving the Digital Ping (S607). Then, RX200 acquires the NFC setting / operation information. The NFC setting information here includes the state information of whether the NFC function of RX200 is valid or invalid, the NFC operation mode, and the NFC identifier information. Here, it is assumed that "NFC function = valid", "operation mode = card emulation mode", and "NFC identifier information = Felica IDm information" are acquired. Then, it notifies TX100 of the received power voltage of the Digital Ping in a Signal Strength Packet (S609) and transitions to the I&C phase.

[0097] Subsequently, RX200 transmits an ID Packet to TX100 (S610). Further, RX200 transmits an Extended Identification Packet to TX100 (S611). The Extended Identification Packet includes the NFC identifier information stored in S602. When TX100 receives the Extended Identification Packet (S611), it stores the identifier information included in this packet (S612).

[0098] Then, RX200 transmits a Configuration Packet to TX100 (S613). This packet includes information that the Neg bit is 1. Therefore, when TX100 responds with an ACK Packet (S614), it transitions to the Negotiation phase.

[0099] When RX200 transitions to the Negotiation phase, it transmits a Specific Request Packet to TX100 (S615). Here, assume that RX200 designates GP = 15 watts in the Specific Request Packet. When the WPC processing unit 301 of TX100 receives this packet, it compares the NFC identifier information specified in S605 with the identifier information stored in S612 (S616). Here, assume that the identifier information matches. The WPC processing unit 301 transmits an ACK Packet to RX200 (S617) and permits the GP specified in S615.

[0100] When the Negotiation phase ends, TX100 and RX200 transition to the Calibration phase and the Power Transfer phase (S618). Then, the charging process for RX200 is started by TX100. TX100 performs the charging process with an output that allows the charging unit 206 of RX200 to receive power at 15 watts.

[0101] When the power reception of the charging unit 206 is completed, RX200 transmits an End Power Transfer Packet to TX100 (S619). Upon receiving this, TX100 stops the charging process for RX200 (S620). When RX200 is removed from TX100 (S621), the response to the Polling process performed by the NFC processing unit 302 ceases (S622). As a result, the NFC processing unit 302 detects that the NFC device has left the communication range (S623). Then, it notifies the WPC processing unit 301 to erase the NFC identifier information notified in S605 (S624). The WPC processing unit 301 receives this and erases the stored NFC identifier information.

[0102] Figure 7 shows an example of the communication sequence between the devices when both RX200 with the NFC function disabled and an NFC tag are brought close to TX100. RX200 may be a device without the NFC function.

[0103] Similar to the description of Figure 6, the NFC processing unit 302 of TX100 periodically performs NFC Polling processing (S701). When the NFC tag comes close to the communication range of the communication regarding the NFC standard, a response to the Polling is made, and the NFC processing unit 302 detects that a device assumed to be the NFC tag has come close (S702). The NFC processing unit 302 reads the NFC identifier information from the response to the Polling and notifies the WPC processing unit 301 (S703).

[0104] Thereafter, the processing of S704 to S709 is the same as that of S605 to S610 in Figure 6, so the description is omitted. However, in the processing of Figure 7, RX200 does not transmit an Extended Identification Packet. That is, the processing corresponding to S611 and S612 in Figure 6 is not performed. Also, regarding the processing of S710 to S712, since it is the same as the processing of S613 to S615 in Figure 6, the description is omitted.

[0105] When the WPC processing unit 301 of TX100 receives a Specific Request Packet (S712), it compares the NFC identifier information specified in S703 with the additional identifier information obtained through WPC communication (S713). In the process of FIG. 7, since an Extended Identification Packet has not been received, there is no additional identifier information obtained through WPC communication. Therefore, the NFC identifier information notified from the NFC processing unit 302 does not match the additional identifier information obtained through WPC communication. As a result, the WPC processing unit 301 transmits a NAK Packet to RX200 (S714) and rejects the GP specified in S712.

[0106] Upon receiving the NAK Packet, RX200 transmits a General Request Packet to TX100 (S715) to request the GP value information of TX100. In response, TX100 transmits a Power Transmitter Capability Packet to RX200 assuming that GP = 0.5 watts (S716).

[0107] When the Negotiation phase ends, TX100 and RX200 transition to the Calibration phase and the Power Transfer phase (S717), and TX100 starts the charging process for RX200. TX100 performs the charging process with an output that allows the charging unit 206 of RX200 to receive power at 0.5 watts.

[0108] When the power reception of the charging unit 206 of RX200 ends, RX200 transmits an End Power Transfer Packet to TX100 (S718). Upon receiving this, TX100 stops the charging process for RX200 (S719).

[0109] Unlike the process of FIG. 6, even if the RX200 is removed from the TX100 (S720), since the NFC processing unit 302 has detected the NFC tag, it does not notify the WPC processing unit 301 of the deletion of the NFC identifier information. Thereafter, when the NFC tag is removed from the TX100 (S721), the response to the Polling process performed by the NFC processing unit 302 is no longer made (S722). As a result, the NFC processing unit 302 detects that the NFC device has left the communication range (S723), and notifies the WPC processing unit 301 to erase the NFC identifier information notified in S703 (S724). The WPC processing unit 301 receives this and erases the stored NFC identifier information.

[0110] (Example of power transmission control in a specific case) Here, the power transmission control in the following cases (1) to (3) will be described.

[0111] (1) When the NFC device includes an NFC tag The NFC tag responds to the Polling process. Further, since the NFC tag does not support the P2P mode, the NFC processing unit 302 determines that there is a specific response (Yes in S405). Subsequently, the NFC processing unit 302 acquires the NFC identifier information from the NFC tag (S408), and notifies the acquired NFC identifier information to the WPC processing unit 301 (S410). Further, if there is an NFC device that has responded to the Polling process in addition to the NFC tag, the NFC identifier information is also acquired from that NFC device (S408), and the acquired NFC identifier information is notified to the WPC processing unit 301 (S410).

[0112] On the other hand, since the NFC tag is not the RX200, the process shown in FIG. 8 is not performed. Therefore, the WPC processing unit 301 does not acquire the NFC identifier information of the NFC tag in the WPC process shown in FIG. 5. Therefore, it becomes No in S516 or S522 of FIG. 5, and the TX100 can limit the power transmission. For example, the TX100 transmits power only at 0.5 watts shown in S524. Or, the power transmission from the TX100 may be stopped.

[0113] (2) When only the RX that supports the P2P mode is included as the NFC device In this case, the NFC device responds to the Polling process using response data including information indicating that it supports the P2P mode, or does not respond at all. Note that the NFC device that does not respond is the RX200 operating in the reader / writer mode.

[0114] Therefore, the NFC processing unit 302 determines that there is no specific response (No in S405). As a result, the NFC processing unit 302 notifies the WPC processing unit 301 that there is no specific NFC device (S406). Also, the NFC processing unit 302 acquires NFC identifier information from the responding NFC device (S408) and notifies the acquired NFC identifier information to the WPC processing unit 301 (S410).

[0115] On the other hand, since the WPC processing unit 301 is notified that there is no specific NFC device, the determination in S515 or S522 of FIG. 5 becomes Yes. Then, the TX100 allows the requested power and power transmission at 15 watts.

[0116] (3) When the NFC device does not include an NFC tag and includes an NFC device that does not support the P2P mode In this case, further classification is made as follows.

[0117] (3-1) When only the RX that does not support the P2P mode and operates in the card emission mode is included as the NFC device In this case, the NFC device responds to the Polling process. However, the response does not include information indicating that it supports the P2P mode. Therefore, the NFC processing unit 302 determines that there is a specific response (Yes in S405). Then, the NFC processing unit 302 acquires NFC identifier information from this NFC device (S408) and notifies the acquired NFC identifier information to the WPC processing unit 301 (S410).

[0118] On the one hand, since this NFC device is operating in card emulation mode, it notifies the TX100 of the NFC identifier information (Yes in S805, S807, S808).

[0119] Therefore, the TX100 determines Yes in S515 in FIG. 5 and further determines Yes in the determination of S516. Alternatively, the TX100 determines Yes in S521 in FIG. 5 and further determines Yes in the determination of S522. Thus, the TX100 allows the required power and power transmission at 15 watts.

[0120] (3-2) When both an RX operating in card emulation mode that does not support the P2P mode and an RX operating in reader / writer mode are included as the NFC device In this case, the RX operating in reader / writer mode does not respond to the Polling process, but the RX operating in card emulation mode responds. And since the response does not include information indicating that the P2P mode is supported, the NFC processing unit 302 determines that there is a specific response (Yes in S405). Also, since there is no response from the RX operating in reader / writer mode, the NFC processing unit 302 acquires the NFC identifier information only from the RX operating in card emulation mode (S408). Then, the NFC processing unit 302 notifies the acquired NFC identifier information to the WPC processing unit 301 (S410).

[0121] On the one hand, the RX operating in card emulation mode notifies the TX100 of the additional identifier information (Yes in S805, S807, S808). However, the RX operating in reader / writer mode does not notify the TX100 of the additional identifier information (No in S805, S806).

[0122] Therefore, TX100 obtains the same identifier information from the RX operating in the card emission mode only by the WPC processing unit 301 and the NFC processing unit 302. Therefore, in S515 in FIG. 5, it is determined as Yes, and further, in the determination of S516, it is determined as Yes. Alternatively, TX100 determines as Yes in S521 in FIG. 5, and further determines as Yes in the determination of S522. Therefore, TX100 allows the required power and power transmission at 15 watts.

[0123] (3-3) When the NFC device includes only the RX operating in the reader / writer mode that does not support the P2P mode Since the RX operating in the reader / writer mode does not respond to the Polling process, the NFC processing unit 302 determines that there is no specific response (No in S405). As a result, the NFC processing unit 302 notifies the WPC processing unit 301 that there is no specific NFC device (S406). Also, since there is no responding NFC device, the NFC processing unit 302 does not acquire the NFC identifier information.

[0124] On the other hand, since the WPC processing unit 301 is notified that there is no specific NFC device, the determination in S515 or S522 in FIG. 5 becomes Yes. Then, TX100 allows the required power and power transmission at 15 watts.

[0125] (Effect) As described above, when TX100 and RX200 have the above configuration, it is possible to protect the battery-less NFC tag and perform high-output power transmission processing on the RX having the NFC module operating in the card emulation mode.

[0126] Also, in the above-described embodiment, the NFC processing unit always stored the NFC identifier information of the NFC device that responded to Polling. And when the NFC identifier information disappeared (YES in S412), that is, when the NFC device was removed, the disappearance of the NFC identifier information was notified to the WPC processing unit 301 (S413). Similarly, when the error in the NFC processing was resolved, the fact was notified to the WPC processing unit 301. By adopting such a configuration, further effects can be expected when the NFC tag is placed on the charging stand of the TX100 or removed from the charging stand while the RX200 is being charged. That is, even when the RX200 is receiving power from the TX100 and is being charged, it is possible to dynamically change the GP according to the presence or absence of the NFC tag and continue the charging.

[0127] Specifically, when the RX200 is being charged with the GP restricted as described in S524, the NFC processing unit 302 notifies the WPC processing unit 301 that the NFC identifier information has disappeared or the error has been resolved. And when the WPC processing unit 301 receives the notification, it recognizes that the cause for restricting the GP has been eliminated. Therefore, the TX100 requests re-negotiation of the GP from the RX200 and transitions to the Re-negotiation phase defined in the WPC standard to perform re-negotiation of the GP. At this point, since the reason for restricting the GP has been eliminated, in S523, the TX100 can respond with the maximum power transmission output value defined in the WPC standard among the capabilities of the power transmission unit 103 as the GP value.

[0128] Also, since the WPC processing unit 301 sequentially updates whether the NFC tag exists or not, even though the NFC device no longer exists, the WPC processing unit 301 will not erroneously recognize that the NFC tag exists and restrict the GP. Also, even though the NFC processing unit 302 newly detects an NFC device, the WPC processing unit 301 will not erroneously recognize that the NFC tag does not exist and perform power transmission with a high power transmission power without restricting the GP.

[0129] The above is an example of a representative embodiment. However, this embodiment is not limited to the embodiments shown in the specification and drawings, and may be appropriately modified and implemented without changing the gist thereof.

[0130] (Modification Example Regarding Identifier Information) In this embodiment, as the NFC identifier information exchanged between TX100 and RX200, IDm data defined by the Felica standard is exemplified. However, in this embodiment, this is not restrictive, and any information that can uniquely identify a plurality of NFC devices within the range of communication based on the NFC standard of TX100 and WPC communication may be used. For example, it may be UID (Unique Identifier) defined by the standard regarding MIFARE (trademark registration), or the MAC address or UUID (Universally Unique Identifier) of the RX.

[0131] Also, a value calculated by hash calculation based on the whole or a part of the NFC Polling response data, or at least a part including the identifier information of the transmission source of the Polling response data, may be used as the identifier information. In this case, TX100 performs hash calculation on the NFC Polling response data received by the NFC processing unit 302, and notifies the calculated value to the WPC processing unit 301 as the identifier information. On the other hand, RX200 performs the same hash calculation as TX100 on the data read as the NFC Polling response data, and notifies the calculated value to TX in the WPC communication.

[0132] Also, RX200 may include the identifier information of the RX defined by the WPC standard in the response data to the NFC Polling process, and TX100 may acquire this. For example, the Extended Device Identifier information included in the Extended Identification Packet may be used as the response data of the NFC Polling.

[0133] In addition, the identifier information notified from the RX200 as an NFC device in the WPC process may be the identifier information notified from the RX200 in an ID Packet. In this case, in the WPC process of the RX200, the identifier information notified in the ID Packet may be included in the Extended Identification Packet.

[0134] Note that when the identifier information notified from the RX200 as an NFC device in the WPC process is the identifier information notified from the RX200 in an ID Packet, the following configuration may be used. That is, the Extended Identification Packet may not be notified. In this case, the WPC processing unit 301 of the TX100 may compare the identifier information included in the ID Packet notified from the RX200 with the NFC identifier information notified from the NFC processing unit 302. Note that the NFC identifier information notified from the NFC processing unit 302 is the identifier information included in the ID Packet.

[0135] Furthermore, the RX200 may perform a hash calculation based on all or part of the Extended Device Identifier and transmit the calculated value as an NFC Polling response. In this case, the same hash calculation as that of the RX200 is performed on the identifier information of the RX200 included in the Extended Identification Packet received by the WPC processing unit 301 of the TX100. Then, the TX100 may be configured to compare the result of the hash calculation with the value received by the Polling response.

[0136] Note that the above-described hash calculation may be performed by any one of the NFC processing unit 302, the WPC processing unit 301, and other processing units (not shown) of the control unit 101 of the TX100.

[0137] Also, in this embodiment, the identifier information of RX200 has been described as the Extended Device Identifier information included in the Extended Identification Packet. However, the identifier information of RX200 may be other identifier information defined in the WPC standard. Specifically, as other identifier information, it may be the Basic Device Identifier information included in the Identification Packet. Also, as other identifier information, it may be the WPID (Wireless Power ID) information included in the Wireless Power Identification Packet defined in the WPC standard, and the same effect can be obtained.

[0138] Also, if RX200 operates the NFC function in a plurality of categories (Type A / B / F) defined by the NFC standard, data obtained by connecting the NFC identifier information specified for each Type may be used as the identifier information. According to this, even when RX200 operates in the NFC card emulation mode in a plurality of categories, TX100 can determine whether the identifier obtained for each category belongs to RX200.

[0139] Also, as a method for TX100 to obtain the identifier information of RX200 in WPC communication, instead of the Packet shown in the above-described embodiment, it may be obtained using other message packets defined in the WPC standard or extended messages not described in the standard. Furthermore, the identifier information of RX200 may be obtained using communication means such as wireless LAN, Bluetooth (registered trademark), Zigbee (registered trademark), IrDA (Infrared Data Association), Wireless USB, etc.

[0140] (Modification Example Regarding NFC Processing) Also, in this embodiment, as a method for detecting an NFC device in the vicinity of TX100, a method of determining the presence or absence of a response to a Polling request has been described, but other methods may also be used. Further, by additional NFC processing, it may be determined whether the NFC device in the vicinity is an NFC tag (or an NFC module operating in card emulation mode). For example, subsequent to the Polling process, message processing with different NFC functions may be performed to determine whether the NFC read data changes. And when the read data changes, it may be determined that the detected NFC device is not an NFC tag. Also, when the response data obtained by the Polling process includes an information element indicating that it is not an NFC tag, it may be determined that the detected NFC device is not an NFC tag. The NFC device thus determined not to be an NFC tag is excluded from the targets to which the identifier information is notified by the WPC processing unit 301. Thereby, for example, it becomes possible to perform high-output power transmission processing even on an RX200 such as a smartphone in which the process of sending identifier information by WPC communication is not implemented.

[0141] In the process of FIG. 4, the processes of S402 to S403 may be performed after S405. Specifically, it may be configured to determine the presence or absence of a specific response to a Polling request (S401) (S405), and when there is a specific response (Yes in S405), determine whether an error has occurred in the specific response (S402).

[0142] Also, the process of S405 in FIG. 4 may be performed by making the following two determinations separately. That is, the NFC processing unit 302 may determine whether there is a response to the Polling request (S401), and if there is a response, determine whether the response indicates that the P2P mode is not supported. Then, when there is no response, and when there is a response but the response does not indicate that the P2P mode is not supported, the NFC processing unit 302 may perform the process of S406. Note that when there is a response and the response indicates that the P2P mode is not supported, the process may proceed to S407.

[0143] Also, in the above-described embodiment, the process of the NFC processing unit 302 shown in FIG. 4 is continuously and repeatedly executed while the TX100 is activated. However, this embodiment is not limited to this, and this process may be started and stopped at a specific timing. For example, the process of FIG. 4 may be performed while the WPC processing unit 301 is detecting an object in the vicinity by Analog Ping. Thereby, it becomes possible to stop the process of FIG. 4 while there is no object in the vicinity of the TX100, and it becomes possible to reduce the power consumption in the TX100. Also, the process of FIG. 4 may be performed while the WPC processing unit 301 is receiving the Signal Strength Packet until it receives the End Power Transfer Packet. Thereby, it becomes possible to stop the process of FIG. 4 while there is no RX having the WPC function in the vicinity of the TX100, and it becomes possible to further reduce the power consumption in the TX100. Furthermore, the timing at which the TX100 starts the process of FIG. 4 may be when the WPC processing unit 301 is requested to provide a GP equal to or higher than a threshold value previously set by the Specific Request Packet. Thereby, since the TX100 performs the process of FIG. 4 only when performing the power transmission process of the output that may damage the NFC tag, it becomes possible to further reduce the power consumption in the TX100.

[0144] Also, although the program for operating the NFC processing unit 302 has been described as being executed by the control unit 101, it may be executed by another control unit (not shown). Specifically, TX100 may be implemented inside another device (such as a printer, a personal computer, a mobile battery, etc., not shown), and another control unit that executes the control program for the functions of the other device may execute the program for operating the NFC processing unit 302.

[0145] (Modification Example Regarding WPC Processing) Even when TX100 is in a state where it does not limit GP (for example, S523), charging may be continued without damaging the NFC tag. Specifically, while TX100 is transmitting power without limiting GP as described in S523, the NFC processing unit 302 notifies the WPC processing unit 301 that the NFC identifier information has increased or an error has occurred. Then, when the WPC processing unit 301 receives the notification, it recognizes that a cause for limiting GP has occurred. Therefore, TX100 requests re-negotiation of GP from RX200 and transitions to the Re-negotiation phase defined in the WPC standard to perform re-negotiation of GP. Since a reason for limiting GP exists at this point, TX100 can set and respond with a power value that does not damage the NFC tag as GP. Here, the configuration in which TX100 requests re-negotiation of GP from RX200 may be such that TX100 notifies RX200 that the NFC identifier information has disappeared or increased, or an error has been resolved or occurred, and RX200 requests re-negotiation of GP in response to the notification.

[0146] Also, the configuration in which TX100 requests re-negotiation of GP from RX200 may be as follows. That is, TX100 may notify RX200 that the NFC identifier information has disappeared or increased, or an error has been resolved or occurred, and RX200 may request re-negotiation of GP in response to the notification.

[0147] Also, in the above-described embodiment, the power transmission output value at which it is determined that no damage is caused to the NFC tag even when TX100 performs power transmission processing was described as 0.5 watts. However, any other value may be used as long as it is a power value that does not cause damage to the NFC tag. Specifically, when starting power transmission in the Power Transfer phase without transitioning to the Negotiation phase (No in S508), the value of GP may be 5 watts defined by the WPC standard, or it may be another value.

[0148] (Other Modifications) In this embodiment, NFC has been described as an example, but it is not limited thereto. For example, even when RX200 has a communication function that behaves like a tag that performs communication other than NFC that is damaged by high-power power transmission, this embodiment can be applied.

[0149] Also, in this embodiment, an example in which the NFC device is detected by the response to the Polling process by the second communication unit 202 has been described, but it is not limited thereto. Similarly, RX200 may not be detected by communication via the first communication unit 104. For example, the user of RX200 may notify TX100 via the user interface of TX100 that a device that is an NFC device and RX200 has been placed on the charging stand. Even in this case, since an NFC tag may be placed on the charging stand, the above-described NFC process and WPC process may be executed.

[0150] <Other Embodiments> The power transmission method of this wireless power transmission system is not particularly limited. A magnetic field resonance method that transmits power by coupling due to resonance of the magnetic field between the resonator (resonance element) of the power transmission device and the resonator (resonance element) of the power reception device may be used. Also, an electromagnetic induction method, an electric field resonance method, a microwave method, a power transmission method using a laser, etc. may be used.

[0151] The present invention can also be realized by supplying a program that implements one or more functions of the above-described embodiment to a system or apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or apparatus to read and execute the program. It can also be realized by a circuit (for example, ASIC) that implements one or more functions.

[0152] Further, the power transmission device and the power reception device may be, for example, an image input device such as an imaging device (camera, video camera, etc.) or a scanner, or an image output device such as a printer, a copy machine, or a projector. It may also 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.

[0153] Also, the flowcharts shown in FIGS. 4 and 5 start when the control unit of the power transmission device is powered on. Note that the processes shown in FIGS. 4 and 5 are realized by the control unit executing a program stored in the memory of the power transmission device. Also, the process shown in FIG. 8 is realized by the control unit executing a program stored in the memory of the power reception device.

[0154] Also, at least a part of the processes shown in the flowcharts of FIGS. 4, 5, and 8 may be realized by hardware. When realized by hardware, for example, a dedicated circuit may be automatically generated on an FPGA from a program for realizing each step by using a predetermined compiler. Also, a Gate Array circuit may be formed in the same manner as an FPGA and realized as hardware.

Explanation of Reference Numerals

[0155] 100 Power transmission device 101 Control unit 103 Power transmission unit 104 First communication unit 106 Second communication unit 200 Power reception device

Claims

1. A power transmitting means for wirelessly transmitting power to a power receiving device; A polling means for performing polling using NFC communication; A detection means for performing a detection process of an NFC tag; A communication means for receiving identifier information from the power receiving device; Negotiation means for negotiating with the power receiving device, The power transmitting device, wherein the negotiation means determines negotiable power based on a result of the detection process.

2. The power transmitting device according to claim 1 , wherein the negotiation means limits the negotiable power when the NFC tag is detected.

3. 3 . The power transmitting device according to claim 1 , wherein the power transmitting unit transmits power based on information about power requested by the power receiving device when the NFC tag is not detected. 4 .

4. The power transmitting device according to claim 1 , wherein the negotiation means limits the negotiable power when a plurality of objects respond to the Polling.

5. 5. The power transmitting device according to claim 1, wherein the communication unit transmits information indicating the negotiable power when the power receiving device requests capability information of the power transmitting device during negotiation.

6. The power transmitting device according to claim 5 , wherein the information indicating the negotiable power is transmitted using a packet of Power Transmitter capability defined in a Wireless Power Consortium standard.

7. 7. The power transmitting device according to claim 5, wherein the communication unit receives a packet indicating the request, the packet being a General Request packet defined in a Wireless Power Consortium standard.

8. if the NFC tag is not detected, the negotiable power value is a first value; The power transmitting device according to claim 1 , wherein, when the NFC tag is detected, the negotiable power value is a second value that is smaller than the first value.

9. 9. The power transmitting device according to claim 1, further comprising an acquisition unit configured to acquire information used for distinguishing the NFC tag from the power receiving device.

10. The power transmitting device according to claim 9 , wherein the detection unit performs the detection process based on the information acquired by the acquisition unit.

11. A method performed by a power transmitting device, comprising: Polling is performed using NFC communication. Perform NFC tag detection processing, receiving identifier information from the power receiving device; Negotiating with the power receiving device; A method, comprising: determining a negotiable power based on a result of the detection process.

12. A program for causing a computer to execute the control method according to claim 11.

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