Patent ID: 12255469

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, an exemplary embodiment of the present disclosure will be described with reference to the drawings. The following exemplary embodiment is merely an example for explaining the technical idea of the present disclosure, and is not intended to limit the invention to configurations and methods to be described in the exemplary embodiment.

(Configuration of System)

FIG.9illustrates a configuration example of a wireless charging system (wireless power transmitting system) according to the present exemplary embodiment. The present system includes a power transmitting apparatus100and a power receiving apparatus200. Hereinafter, a power transmitting apparatus will be sometimes referred to as a “TX” and a power receiving apparatus will be sometimes referred to as an “RX”. A TX100and a RX200comply with a Wireless Power Consortium (WPC) standard. The RX200receives power from the TX100, and enables charging of a battery. The TX100is an electronic device that wirelessly transmits power to the RX200placed on a charging stand of the TX100. The following description will be given of an example case where the RX200is placed on the charging stand. Nevertheless, the RX200needs not be placed on the charging stand as long as the RX200exists within a power transmittable range of the TX100(range indicated by a broken line illustrated inFIG.9) when the TX100transmits power to the RX200.

The RX200and the TX100can include a function of executing an application other than wireless charging. One example of the RX200is a smartphone, and one example of the TX100is an accessory device for charging the smartphone. The RX200and the TX100may be a tablet computer or a storage device, such as a hard disc device or a memory device, or may be an information processing apparatus, such as a personal computer (PC). The RX200and the TX100may also be an imaging apparatus (e.g., camera, and video camera).

The RX200is equipped with a Near Field Communication (hereinafter, referred to as “NFC”) function. Using the NFC function, the RX200can read an NFC tag and perform electronic money payment, for example. The TX100is also equipped with an NFC function for reading an NFC tag. Thus, the TX100can detect an NFC tag by performing communication based on a standard of NFC. Furthermore, the TX100can stop or restrict power transmission processing for protecting an NFC tag, based on the detection result.

The system performs wireless power transmission using an electromagnetic induction method for wireless charging, based on the WPC standard. More specifically, the RX200and the TX100perform wireless power transmission for wireless charging based on the WPC standard, between a power receiving antenna of the RX200and a power transmitting antenna of the TX100. The wireless power transmitting method (contactless power transmitting method) applied to the system is not limited to a method defined by the WPC standard, and may be another electromagnetic induction method, a magnetic field resonance method, an electric field resonance method, a microwave method, or a method that uses laser. In addition, in the present exemplary embodiment, wireless power transmission is used for wireless charging, but wireless power transmission may be performed for the purpose other than wireless charging.

In the WPC standard, the magnitude of power guaranteed when the RX200receives power from the TX100is defined by a value called Guaranteed Power (hereinafter, referred to as “GP”). The GP indicates a value of power guaranteed to be output to the load (e.g., circuit for charging) of the RX200even if a positional relationship between the RX200and the TX100varies, for example, and the efficiency of power transmission between the power receiving antenna and the power transmitting antenna declines. For example, in a case where the GP is 5 watt, the TX100performs power transmission while performing control in such a manner that 5 watt can be output to the load in the RX200, even if a positional relationship between the power receiving antenna and the power transmitting antenna varies and power transmission efficiency declines.

The RX200and the TX100according to the present exemplary embodiment perform communication for power transmission and reception control based on the WPC standard. The WPC standard defines a plurality of phases including a Power Transfer phase in which power transmission is executed and phases before a phase in which actual power transmission is performed. In each phase, communication necessary for power transmission and reception control 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 an I&C phase.

In the Selection phase, the TX100intermittently transmits an Analog Ping, and detects that an object (e.g., the RX200or a conductor strip) is placed on a charging stand of the TX100. The TX100detects at least either one of a voltage value and a current value of the power transmitting antenna that are obtained when the Analog Ping is transmitted. If the voltage value falls below a certain threshold value or if the current value exceeds a certain threshold value, the TX100determines that an object exists, and transitions to the Ping phase.

In the Ping phase, the TX100transmits a Digital Ping larger in power than the Analog Ping. The magnitude of power of the Digital Ping is power sufficient for activating a control unit of the RX200placed on the charging stand of the TX100. The RX200notifies the TX100of the magnitude of received voltage. In this manner, by receiving a response from the RX200that has received the Digital Ping, the TX100recognizes that the object detected in the Selection phase is the RX200.

When the TX100receives a notification of a received voltage value, the TX100transitions to the I&C phase. In the I&C phase, the TX100identifies the RX200, and acquires device configuration information (capability information) from the RX200. Thus, the RX200transmits an ID Packet and a Configuration Packet to the TX100. The ID Packet includes identifier information of the RX200, and the Configuration Packet includes device configuration information (capability information) of the RX200. The TX100, which has received the ID Packet and the Configuration Packet, transmits an acknowledge response (ACK, positive response). The I&C phase then ends.

In the Negotiation phase, a value of GP is determined based on, for example, a value of GP requested by the RX200and power transmission capability of the TX100.

In the Calibration phase, the RX200notifies the TX100of a received power value based on the WPC standard, and the TX100performs adjustment for efficiently transmitting power.

In the Power Transfer phase, control for starting or continuing power transmission, and for stopping power transmission due to an error or full charge is performed.

For such power transmission and reception control, the TX100and the RX200perform communication (hereinafter, referred to as “first communication”) of superimposing a signal onto electromagnetic waves transmitted from an antenna, using the same antenna (coil) as wireless power transmission based on the WPC standard. A range within which the first communication based on the WPC standard can be performed between the TX100and the RX200is substantially similar to the power transmittable range (range indicated by the broken line illustrated inFIG.9) of the TX100.

The TX100and the RX200may perform communication (hereinafter, referred to as “second communication”) for such power transmission and reception control using a different antenna and frequency from those used in wireless power transmission. For example, the frequency band of electromagnetic waves used in the second communication is higher than the frequency band of electromagnetic waves used in the first communication. In this case, the second communication can bring higher-speed communication than that used in the first communication.

As an example of the second communication, there is a communication method that complies with the Bluetooth® Low Energy (hereinafter, referred to as “BLE”) standard. In this case, the TX100operates as a Peripheral of BLE and the RX200operates as a Central of BLE. However, these roles of BLE may be opposite. Alternatively, the second communication may be performed by another communication method, such as an Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard series wireless local area network (LAN) (e.g., Wi-Fi®) or ZigBee®. When the TX100can perform the second communication and the RX200exists within the power transmittable range, the RX200and the TX100can exchange information via the second communication.

(Apparatus Configuration)

Configurations of the power transmitting apparatus100(TX100) and the power receiving apparatus200(RX200) according to the present exemplary embodiment will now be described. The following configurations are merely examples, and a part (or all in some cases) of the configurations to be described below may be omitted or replaced with other configurations having other similar functions, or additional configurations may be added to the configurations to be described below. Furthermore, one block to be described below may be divided into a plurality of blocks or a plurality of blocks may be integrated into one block.

FIG.1is a block diagram illustrating a configuration example of the TX100according to the present exemplary embodiment. The TX100includes a control unit101, a power source unit102, a power transmitting unit103, a first communication unit104, a power transmitting antenna105, a second communication unit106, and a memory107. Although the control unit101, the power source unit102, the power transmitting unit103, the first communication unit104, the second communication unit106, and the memory107are illustrated as separate blocks inFIG.1, a plurality of arbitrary blocks of these blocks may be mounted on the same chip.

The control unit101controls the entire TX100by executing a control program stored in the memory107, for example. The control unit101performs control related to power transmission control including communication for device authentication in the TX100. Furthermore, the control unit101may perform control for executing an application other than wireless power transmission. The control unit101includes one or more processors, such as a central processing unit (CPU) or a microprocessor unit (MPU). The control unit101may include hardware dedicated for specific processing, such as an application specific integrated circuit (ASIC). The control unit101may also include an array circuit, such as a field programmable gate array (FPGA) compiled to execute predetermined processing. The control unit101stores, into the memory107, information to be stored during the execution of various types of processing. In addition, the control unit101can measure a time using a timer (not illustrated).

The power source unit102supplies power to each block. The power source unit102is, for example, a commercial power source or a battery. Power supplied from the commercial power source is stored in the battery.

The power transmitting unit103generates electromagnetic waves to be received by the RX200, by converting direct-current or alternating-current power input from the power source unit102, into alternating-current frequency power in the frequency band used for wireless power transmission, and inputting the alternating-current frequency power to the power transmitting antenna105. For example, the power transmitting unit103converts direct-current voltage supplied by the power source unit102, into alternating-current voltage using a switching circuit having a half-bridge or full-bridge configuration that uses a field effect transistor (FET). In this case, the power transmitting unit103includes a gate driver for controlling ON/OFF of the FET.

The power transmitting unit103controls the intensity of electromagnetic waves to be output, by adjusting either or both of voltage (power transmission voltage) and current (power transmission current) input to the power transmitting antenna105. If the power transmission voltage or the power transmission current is made large, the intensity of electromagnetic waves becomes high. In contrast, if the power transmission voltage or the power transmission current is made small, the intensity of electromagnetic waves becomes low. The power transmitting unit103performs output control of alternating-current frequency power in such a manner as to start or stop power transmission from the power transmitting antenna105, based on an instruction from the control unit101. The power transmitting unit103has a capability of supplying power for outputting 15-watt electric power to a charging unit of the RX200that complies with the WPC standard.

The first communication unit104performs, with the RX200, the above-described communication for power transmission control based on the WPC standard. The first communication unit104performs the first communication by modulating electromagnetic waves output from the power transmitting antenna105, and transmitting information to the RX200. The first communication unit104also acquires information transmitted by the RX200, by demodulating electromagnetic waves output from the power transmitting antenna105and modulated by the RX200. In other words, the first communication performed by the first communication unit104is executed in such a manner that a signal is superimposed on electromagnetic waves transmitted from the power transmitting antenna105. The first communication unit104may communicate with the RX200using the second communication in place of the first communication, or may communicate with the RX200selectively using the first communication and the second communication. In a case where the first communication unit104performs the second communication, the TX100includes an antenna different from the power transmitting antenna105.

The second communication unit106communicates with another NFC device using an NFC function. The NFC device in the present exemplary embodiment includes an NFC tag unless otherwise stated. By using the second communication unit106, the TX100can detect the existence of an NFC tag. If an NFC tag is detected by the second communication unit106, the control unit101restricts power transmission by controlling the power transmitting unit103to stop power transmission or lower the power of power transmission. The second communication unit106includes an antenna (not illustrated) different from the power transmitting antenna105.

The second communication unit106is controlled by the control unit101, but the second communication unit106may be controlled by a control unit of a not illustrated different device (camera, smartphone, tablet PC, or laptop PC) that includes the TX100.

The memory107also stores states of the TX100and the RX200in addition to control programs.

FIG.2is a block diagram illustrating a configuration example of the RX200according to the present exemplary embodiment. The RX200includes a control unit201, a second communication unit202, a power receiving unit203, a first communication unit204, a power receiving antenna205, a charging unit206, a battery207, and a memory208. A plurality of blocks illustrated inFIG.2may be implemented as one hardware module.

The control unit201controls the entire RX200by executing a control program stored in, for example, the memory208. In other words, the control unit201controls each functional unit illustrated inFIG.2. Furthermore, the control unit201may perform control for executing an application other than wireless power transmission. As an example, the control unit201includes one or more processors, such as a CPU or a MPU. The control unit201may control the entire smartphone in cooperation with an operating system (OS) executed by the control unit201.

The control unit201may include hardware, such as an ASIC, dedicated for specific processing. The control unit201may include an array circuit, such as an FPGA compiled to execute predetermined processing. The control unit201stores, into the memory208, information to be stored during the execution of various types of processing. In addition, the control unit201can measure a time using a timer (not illustrated).

The second communication unit202performs communication processing with another communication device using an NFC function. The second communication unit202operates in a mode that complies with a standard stipulated by, for example, the NFC forum. The above-described mode includes, for example, a card emulation mode for playing an alternative role as a contactless IC card, a reader/writer mode for reading an NFC tag, and a Peer to Peer mode (P2P) mode for directly exchanging messages between NFC devices. For example, electronic money payment becomes executable by using the card emulation mode.

The second communication unit202includes an antenna (not illustrated), which is different from the power receiving antenna205, for performing communication based on the standard of NFC. The second communication unit202is controlled by the control unit201. However, the second communication unit202may be controlled by a control unit of a not illustrated different device (camera, smartphone, tablet PC, or laptop PC) that includes the RX200.

The power receiving unit203acquires, with the power receiving antenna205, alternating-current power (alternating-current voltage and alternating current) generated by electromagnetic induction generated by electromagnetic waves emitted from the power transmitting antenna105of the TX100. The power receiving unit203converts the alternating-current power into direct current or alternating-current power at a predetermined frequency, and outputs power to the charging unit206, which performs processing for charging the battery207. In other words, the power receiving unit203supplies power to the load in the RX200. The above-described GP is an amount of power guaranteed to be output from the power receiving unit203. The power receiving unit203has a capability of supplying power for the charging unit206to charge the battery207, and a capability of supplying power for outputting 15-watt power to the charging unit206.

The first communication unit204performs the above-described communication for power receiving control based on the WPC standard, with the first communication unit104included in the TX100. The first communication unit204acquires information transmitted from the TX100, by demodulating electromagnetic waves input from the power receiving antenna205. The first communication unit204performs load modulation of the input electromagnetic waves and thereby superimposes a signal related to information to be transmitted to the TX100, onto the electromagnetic waves. The first communication unit204thereby performs the first communication with the TX100. The first communication unit204may communicate with the TX100using the second communication in place of the first communication, or may communicate with the TX100selectively using the first communication and the second communication. In a case where the first communication unit204performs the second communication, the RX200includes an antenna different from the power receiving antenna205.

The memory208also stores states of the TX100and the RX200in addition to the control program.

A function block diagram of the control unit101of the TX100will now be described with reference toFIG.3. The control unit101includes a WPC processing unit301and an NFC processing unit302. The WPC processing unit301is a processing unit that performs control communication of wireless power transmission based on the WPC standard, via the first communication unit104. The WPC processing unit301controls the power transmitting unit103, and controls power transmission to the RX200. The NFC processing unit302is a processing unit that performs communication related to the standard of NFC, via the second communication unit106. The WPC processing unit301and the NFC processing unit302concurrently operate as independent programs. The functions of the WPC processing unit301and the NFC processing unit302are executed by the programs being executed by the control unit101.

Procedures of processing performed by the NFC processing unit302in the TX100and processing performed by the WPC processing unit301in the TX100will now be described with reference toFIGS.4and5.

[Processing Performed by NFC Processing Unit]

FIG.4is a flowchart illustrating a processing operation of the NFC processing unit302. The processing is continuously and repeatedly executed while the TX100is in an activated state.

In step S401, the second communication unit106starts NFC Polling processing when the TX100is activated. Specifically, the second communication unit106transmits a Polling request, and monitors the proximity of another NFC device by monitoring a response to the Polling request. If an error has been detected as a result of Polling processing (YES in step S402), the processing proceeds to step S403. In step S403, the NFC processing unit302notifies the WPC processing unit301that an error has occurred in NFC processing. The error means a failure in communication related to the standard of NFC, and does not include the result of no response to the Polling request i.e., nonexistence of an NFC device as a communication partner. An example of the error is a so-called collision error. In the collision error, response data cannot be properly received when a plurality of other NFC devices existing within a communication range of communication related to the standard of NFC makes a response at the same timing.

If such an error occurs, it cannot be checked whether detected NFC devices include an NFC tag driven without a battery, because NFC cannot be properly performed with another NFC device existing within the communication range. Thus, the NFC processing unit302notifies the WPC processing unit301of a possibility of proximity of an NFC tag, and the WPC processing unit301that has received the notification avoids performing power transmission processing with high power, thereby reducing the possibility of damaging the NFC tag.

If an error has not been detected as a result of Polling processing (NO in step S402), the processing proceeds to step S404. In step S404, the NFC processing unit302notifies the WPC processing unit301that no error has occurred in NFC processing. Even when the error has been resolved, the NFC processing unit302notifies that no error has occurred in NFC processing.

In step S405, the NFC processing unit302determines whether a specific response to the Polling request transmitted in step S401has been received. The specific response is a response indicating that a device does not support the P2P mode. If the specific response has not been received (NO in step S405), the processing proceeds to step S406. In step S406, the NFC processing unit302notifies the WPC processing unit301that a specific NFC device does not exist nearby. The NFC processing unit302may notify that a specific NFC device does not exist nearby, only if the specific response to a plurality of consecutive Polling requests has not been received.

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. A device operating in the reader/writer mode does not make a response to a Polling request irrespective of whether the device supports the P2P mode. Thus, the NFC processing unit302determines as NO in step S405, if the NFC processing unit302cannot detect a device operating in the reader/writer mode, and only a device operating in the reader/writer mode is placed on the charging stand.

A case where a specific response has not been received includes the following cases: a case where a device performing communication related to the standard of NFC does not exist, a case where an NFC device exists but the NFC device does not make a response to a Polling request, and a case where a device makes a response to a Polling request but the device supports the P2P mode. The case where the device supports the P2P mode refers to a case where an NFC device is operable in the P2P mode. For example, a case where an NFC device supports the P2P mode even if the NFC device is operating in the card emulation mode also refers to the case where the NFC device supports the P2P mode. In a case where a device supports the P2P mode, response data to a Polling request includes information indicating that the P2P mode is supported. Thus, the NFC processing unit302can determine whether a detected NFC device supports the P2P mode, based on response data.

On the other hand, if a specific response has been received (YES in step S405), the NFC processing unit302repeats the processing in steps S407to S411the number of times corresponding to the number of received responses. In step S408, the NFC processing unit302acquires identifier information (hereinafter, sometimes referred to as “NFC identifier information”) of each NFC device included in each piece of received response data. In this step, the NFC processing unit302acquires NFC identifier information of an NFC device that has made the response irrespective whether a response to a Polling request is a specific response. The NFC processing unit302can detect that an NFC device exists nearby, based on the presence or absence of a response.

The NFC identifier information is identifier information that makes another NFC device existing within an NFC communication range, uniquely identifiable. In the present exemplary embodiment, the NFC identifier information is IDm data used in the FeliCa® technique. The standard of NFC defines a region called IDm as a format of communication data, and defines content of data designated in the IDm region by the standard related to Felica. Thus, IDm data used in the FeliCa technique is used in the present exemplary embodiment. Nevertheless, the NFC identifier information is not limited to this as described below.

If NFC identifier information has been acquired (YES in step S409), the processing proceeds to step S410. In step S410, the NFC processing unit302notifies the WPC processing unit301of the acquired NFC identifier information. If NFC identifier information has failed to be acquired (NO in step S409), the processing proceeds to step S411. In step S411, the NFC processing unit302notifies the WPC processing unit301that an error has occurred in NFC processing.

After the identifier acquisition processing (steps S408to411) has been performed for NFC devices included in all pieces of response data, the NFC processing unit302compares NFC identifier information acquired in the previous NFC processing and NFC identifier information acquired in the current NFC processing. As a result of comparison, the processing proceeds to step S413, if there is any NFC identifier information that has not been acquired in the current NFC processing, among pieces of NFC identifier information acquired in the previous NFC processing (YES in step S412). In step S413, the NFC processing unit302notifies the WPC processing unit301of nonexistence of NFC identifier information and the NFC identifier information. If identifier acquisition has failed in the previous Polling processing, and identifier acquisition has not failed in the current Polling processing, the NFC processing unit302notifies the WPC processing unit301that an error of NFC processing has been resolved.

The NFC processing unit302sequentially notifies the WPC processing unit301of an error status of NFC processing and acquired NFC identifier information. However, the NFC processing is not limited to this. A notification to the WPC processing unit301may be collectively performed after all pieces of processing have been executed. The notification to the WPC processing unit301includes a notification of error occurrence (step S402), a notification of non-detection of response data (step S405), a notification of acquired NFC identifier information (step S410), and a notification of an acquisition failure of NFC identifier information (step S411). The acquired NFC identifier information may be made into a list, and the list may also be notified to the WPC processing unit301.

[Processing Performed by WPC Processing Unit]

FIG.5is a flowchart illustrating a processing operation of the WPC processing unit301. The processing is also continuously and repeatedly executed while the TX100is in an activated state.

In step S501, the WPC processing unit301performs Selection phase processing after the TX100is activated. Specifically, the WPC processing unit301transmits an Analog Ping via the power transmitting unit103and the power transmitting antenna105. The TX100detects at least either one of a voltage value and a current value of the power transmitting antenna105that are obtained when the Analog Ping is transmitted. If a voltage value falls below a certain threshold value or if a current value exceeds a certain threshold value, the TX100determines that an object exists near the power transmitting antenna105, and transitions to the Ping phase.

In Ping phase processing in step S502, the TX100transmits a Digital Ping lager than the Analog Ping. The magnitude of the Digital Ping is power sufficient for activating at least the control unit201of the RX200existing near the power transmitting antenna105. When the TX100receives a received voltage notification for notifying the magnitude of received voltage from the RX200, the TX100transitions to the I&C phase. The TX100recognizes that an object placed on the charging stand is the RX200by receiving the received voltage notification via the first communication unit104.

In step S503, the TX100receives an ID Packet transmitted from the RX200in the I&C phase. In step S504, the TX100refers to an information bit (Ext bit) included in the ID Packet, and determines whether additional identifier information is to be transmitted from the RX200.

If an Ext bit is 1 (YES in step S504), the TX100determines that additional identifier information is to be transmitted, and the processing proceeds to step S505. In step S505, the TX100waits for an Extended Identification Packet to be transmitted from the RX200, and receives the Packet. The Packet includes an octet Extended Device Identifier of the RX200at most. In step S506, the TX100stores the additional identifier information into the memory107as NFC identifier information. In other words, the additional identifier information is stored into the memory107as NFC identifier information acquired in NFC processing unlike identifier information included in an ID Packet.

In step S507, the TX100receives a Configuration Packet transmitted from the RX200. In step S508, the TX100refers to an information bit (Neg bit) included in the Packet, and determines whether to transition to the Negotiation phase.

In the Negotiation phase, the TX100negotiates with the RX200for determining the above-described GP. If the Neg bit is 0 (NO in step S508), the processing proceeds to step S509. In step S509, the TX100transmits an ACK Packet to the RX200. At this time, in step S510, the TX100transitions to the Power Transfer phase without transitioning to the Negotiation phase, and executes power transmission processing with respect to the RX200with low power. The low power is a power transmission output value determined not to damage an NFC tag even if the TX100performs power transmission processing. The low power may be, for example, an arbitrarily-set value, or a value set based on at least one of power, current, and voltage defined by the WPC standard or another standard.

If the Neg bit is 1 (YES in step S508), the processing proceeds to step S511. In step S511, the TX100transmits an ACK Packet to the RX200, and transitions to the Negotiation phase. In the processing in the Negotiation phase (steps S512to S524), the TX100waits for a Specific Request Packet or a General Request Packet to be transmitted from the RX200.

When the TX100receives a Specific Request Packet (YES in step S512), the TX100determines whether a value of GP designated in the Packet can be allowed (steps S513to S518). The Specific Request Packet includes candidate values of power (GP) requested by the RX200. In step S513, the TX100firstly determines whether the value of the designated GP is smaller than a preset threshold value. The threshold value herein is a threshold value of a power transmission output determined not to damage an NFC tag even if power transmission processing is performed. If the value of the designated GP is smaller than the threshold value (NO in step S513), the processing proceeds to step S517. In step S517, the TX100allows the value of the designated GP, and transmits an ACK Packet to the RX200.

If the value of the designated GP is equal to or larger than the threshold value (YES in step S513), the processing proceeds to step S514. In step S514, the TX100determines whether an error has occurred in NFC processing. Specifically, the WPC processing unit301determines whether the occurrence of an error has been notified from the NFC processing unit302(step S413or S411inFIG.4). If an error has occurred in NFC processing (YES in step S514), there is a possibility that an NFC tag exists within the communication range of the TX100. Thus, in step S518, the TX100refuses the value of requested GP that is equal to or larger than the threshold value, and transmits a Negative Acknowledgement (NAK) Packet to the RX200. Thereafter, the TX100continues to wait for a Specific Request Packet or a General Request Packet.

If an error has not occurred in NFC processing, for example (NO in step S514), the processing proceeds to step S515. In step S515, the TX100determines the presence or absence of an NFC device that has made a specific response to a Polling request. Specifically, the TX100performs the determination based on whether the NFC processing unit302notifies the WPC processing unit301that a specific NFC device does not exist (step S406inFIG.4).

If a specific NFC device that has made a response to a Polling request does not exist (NO in step S515), the processing proceeds to step S517. In step S517, the TX100allows the value of the designated GP, and transmits an ACK Packet to the RX200.

If a specific NFC device that has made a response to a Polling request exists (YES in step S515), the processing proceeds to step S516. In step S516, the TX100determines whether an NFC device detected in NFC processing and the RX200detected in WPC processing are the same devices. Specifically, the WPC processing unit301compares NFC identifier information notified from the NFC processing unit302, and additional identifier information stored in the processing in step S506, and determines whether these pieces of identifier information match. If the pieces of identifier information match, the WPC processing unit301determines that an NFC device detected in NFC processing and the RX200detected in WPC processing are the same devices.

If the WPC processing unit301determines that an NFC device detected in NFC processing and the RX200detected in WPC processing are the same devices (YES in step S516), the processing proceeds to step S517. In step S517, the TX100allows the value of the designated GP, and transmits an ACK Packet to the RX200. In this case, the TX100determines that the RX200includes a power source for executing communication processing of WPC, and power of some sort is supplied to a module of the RX200that executes an NFC function. The TX100therefore determines that an NFC device detected by the NFC processing unit302is not damaged even if power transmission processing is performed with an output that is equal to or larger than the threshold value, and allows the value of the GP designated by the RX200.

If an NFC device detected in NFC processing and the RX200detected in WPC processing are not the same devices (NO in step S516), the processing proceeds to step S518. In step S518, the TX100refuses the value of requested GP that is equal to or larger than the threshold value, and transmits a NAK Packet to the RX200. Since an NFC tag is not the RX200, WPC processing as illustrated inFIG.5is not executed, and NFC identifier information is not transmitted to the TX100. It is thereby determined that an NFC device detected in NFC processing and the RX200detected in WPC processing are not the same devices. Thereafter, the TX100continues to wait for a Specific Request Packet or a General Request Packet.

If a plurality of pieces of NFC identifier information is notified from the NFC processing unit302, in step S518, the TX100transmits a NAK Packet to the RX200unless otherwise corresponding additional identifier information is stored for all pieces of NFC identifier information in the processing performed in step S506. In other words, if additional identifier information corresponding to any of a plurality of identifiers notified from the NFC processing unit302is not stored in step S506, the TX100transmits a NAK Packet to the power receiving apparatus200. In contrast, if corresponding additional identifier information is stored in the processing in step S506for all pieces of NFC identifier information notified from the NFC processing unit302, in step S517, the TX100transmits an ACK Packet to the RX200.

A case where the TX100receives a General Request Packet will now be described. The TX100receives a Packet for requesting the capability of the TX100(Power Transmitter capability) to be notified, among General Request Packets (NO in step S512, and YES in step S519). In this case, the TX100performs determination processing for determining a value of GP to be notified to the RX200in a response Packet of the Packet (steps S520to S524).

In step S520, the TX100firstly determines whether an error has occurred in NFC processing. The determination method is the same as that used in the processing in step S514. If an error has occurred in NFC processing (YES in step S520), the processing proceeds to step S524. In step S524, the TX100transmits a response indicating that a GP value is a power transmission output value that can be determined not to damage an NFC tag even if power transmission processing is performed. In this step, the TX100transmits a response indicating that GP=0.5 watts. The value of GP is not limited to 0.5 watts, and is only required to be a power value that does not damage an NFC tag. In addition, the value of GP may be zero watts, or the RX200may be notified that power transmission is not to be performed.

If an error has not occurred in NFC processing (NO in step S520), the processing proceeds to step S521. In step S521, the TX100determines the presence or absence of a specific NFC device that has made a response to a Polling request. The determination method is the same as that used in the processing in step S515. If a specific NFC device that has made a response to a Polling request does not exist (NO in step S521), the processing proceeds to step S523. In step S523, the TX100transmits a response indicating that a GP value is the largest power transmission output value defined by the WPC standard, among the capabilities of the power transmitting unit103. In this step, the TX100transmits a response indicating that GP=15 watts. The value of GP is an example, and is not limited to this.

If a specific NFC device that has made a response to a Polling request exists (YES in step S521), the processing proceeds to step S522. In step S522, the TX100determines whether an NFC device detected in NFC processing and the RX200detected in WPC processing are the same devices. The determination method is the same as that used in the processing in step S516.

If it is determined that an NFC device detected in NFC processing and the RX200detected in WPC processing are the same devices (YES in step S522), the processing proceeds to step S523. In step S523, the TX100transmits a response indicating that a GP value is the largest power transmission output value defined by the WPC standard, among the capabilities of the power transmitting unit103. In contrast, if it is determined that an NFC device detected in NFC processing and the RX200detected in WPC processing are not the same devices (NO in step S522), the processing proceeds to step S524. In step S524, the TX100transmits a response indicating that a GP value is a power transmission output value that can be determined not to damage an NFC tag even if power transmission processing is performed. In other words, if it is determined that an NFC device detected in NFC processing and the RX200detected in WPC processing are the same devices, the TX100sets lager GP as compared with a case where it is determined that the an NFC device and the RX200are not the same devices, and performs power transmission based on the GP.

In step S525, if the TX100receives a Specific Request Packet for requesting an end of the Negotiation phase from the RX200, the TX100transitions to the Calibration phase. In the Calibration phase, the TX100determines parameters necessary for a foreign object detection function of detecting that an object different from the RX200exists near the power receiving antenna205. The TX100adjusts a power transmission output such that the RX200can perform charging using the GP allowed in step S517, or the GP included in the response transmitted in step S523or S524.

Thereafter, the TX100transitions to the Power Transfer phase (step S526), and supplies power to the charging unit206of the RX200. The TX100continues power transmission processing until receiving an End Power Transfer Packet from the RX200.

[WPC Processing in RX]

An operation procedure of WPC processing in the RX200will now be described with reference toFIG.8. The processing is repeatedly executed while a setting of executing a charging function based on WPC is set in the RX200.

If the control unit201of the RX200receives the Digital Ping transmitted from the TX100(YES in step S801), the processing proceeds to step S802. In step S802, the control unit201detects that the TX100exists nearby. Upon detecting the existence, in step S803, the control unit201acquires NFC setting/operation information in the second communication unit202. The setting/operation information includes a state indicating whether an NFC function in the RX200is enabled or disabled, an operation mode of NFC, and NFC identifier information that makes an NFC device uniquely identifiable as an NFC device. The operation mode of NFC indicates an operation mode of NFC in the second communication unit202, and indicates any one mode of the following three modes: the card emulation mode, the reader/writer mode, and the P2P mode. In step S804, the control unit201subsequently notifies the TX100of received voltage of the Digital Ping via the first communication unit204using a Signal Strength Packet.

In step S805, the control unit201selects a Packet to be transmitted next, in accordance with the NFC communication setting/operation information acquired in step S803. Specifically, if the NFC function is enabled and an operation mode of NFC is the card emulation mode (YES in step S805), the processing proceeds to step S807. In step S807, the control unit201transmits an ID Packet to the TX100. The control unit201sets an Ext bit to 1 in the ID Packet transmitted in this step, and notifies the TX100that an Extended Identification Packet is to be subsequently transmitted.

In step S808, the control unit201subsequently sets the NFC identifier information acquired in step S803in the Extended Identification Packet, and transmits the Extended Identification Packet to the TX100.

If the NFC function is disabled or if the NFC function is enabled but an operation mode is other than the card emulation mode (NO in step S805), the control unit201does not transmit an Extended Identification Packet. In other words, in step S806, the control unit201transmits an Identification Packet in which an Ext bit is set to 0, to the TX100. In this manner, it becomes possible to suppress unnecessary communication by determining whether to transmit a Packet, in accordance with an operation state of the NFC function in the RX200. Power consumption in both the TX100and the RX200can thereby be reduced.

In step S809, the control unit201transmits a Configuration Packet to the TX100, and transmits, to the TX100, a request to transition to the Negotiation phase in which negotiation for determining GP is performed. When the RX200receives an ACK Packet from the TX100(YES in step S810), the RX200transitions to the Negotiation phase. If the RX200has not received an ACK Packet for a certain period of time (NO in step S810), the RX200transitions to the Selection phase, and returns a processing state to waiting processing for a Digital Ping.

If the RX200transitions to the Negotiation phase, in step S811, the control unit201transmits a Specific Request Packet in which 15 watts is designated as a candidate of GP, to the TX100. When the RX200receives an ACK Packet from the TX100(YES in step S812), the processing proceeds to step S813. In step S813, the RX200determines that a 15-watt GP has been allowed by the TX100, and GP in power receiving processing is determined to be 15 watts.

In addition, if the RX200receives a NAK Packet from the TX100(NO in step S812, and YES in step S814), the RX200determines that the 15-watt GP has been refused by the TX100. In this case, the RX200transmits, in step S815, a General Request Packet to the TX100, and requests a GP candidate in the TX100. In step S816, the RX200receives a Power Transmitter Capability Packet from the TX100. In step S817, a value of the GP candidate in the TX100t included in the Power Transmitter Capability Packet is determined to be GP used in the current charging processing.

If the RX200receives neither an ACK Packet nor a NAK Packet (NO in step S814), the RX200transitions to the Selection phase, and returns a processing state to waiting processing for a Digital Ping.

When negotiation of GP ends, in step S818, the TX100and the RX200transition to the Calibration phase. In the Calibration phase, the TX100determines parameters necessary for a foreign object detection function of detecting that an object different from the RX200exists near the power receiving antenna205. In addition, in the Calibration phase, the RX200also performs processing of supplying power to the charging unit206serving as a load, from the power receiving unit203.

Thereafter, in step S819, the TX100and the RX200transition to the Power Transfer phase, and the RX200charges the battery207. When the charging ends (YES in step S820), the processing proceeds to step S821. In step S821, the RX200transmits an End Power Transfer Packet to the TX100, and notifies the TX100of an end of charging processing.

[Sequence of Wireless Power Transmitting System]

A sequence of a wireless power transmitting system including the TX100and the RX200will now be described with reference toFIG.6.FIG.6illustrates an example of a communication sequence between the TX100and the RX200that is performed when the RX200is brought closer to the TX100.

In step S601, the RX200firstly operates the NFC function of the second communication unit202in the card emulation mode.

In contrast, in step S602, the NFC processing unit302of the TX100periodically executes Polling processing based on the standard of NFC. If the RX200comes close to the inside of an NFC communication range, the RX200makes a response to a Polling request, and in step S603, the NFC processing unit302detects that an NFC device has come close. In step S604, the NFC processing unit302reads NFC identifier information from the response to the Polling request, and notifies the WPC processing unit301of the NFC identifier information.

In step S605, the WPC processing unit301of the TX100periodically transmits an Analog Ping, and if the WPC processing unit301determines that an object exists near the power transmitting antenna105, in step S606, the WPC processing unit301transmits a Digital Ping.

In step S607, the RX200detects the TX100by receiving the Digital Ping. In step S608, the RX200then acquires NFC setting/operation information. The NFC setting information herein includes state information indicating whether the NFC function of the RX200is enabled or disabled, an operation mode of NFC, and NFC identifier information. In this example, the following information is acquired: “NFC function=enabled”, “operation mode=card emulation mode”, and “NFC identifier information=IDm information of Felica”. In step S609, the RX200notifies the TX100of received voltage of a Digital Ping using a Signal Strength Packet, and transitions to the I&C phase.

In step S610, the RX200subsequently transmits an ID Packet to the TX100. In step S611, the RX200further transmits an Extended Identification Packet to the TX100. The Extended Identification Packet includes NFC identifier information stored in step S602. In step S611, the TX100receives the Extended Identification Packet. In step S612, the TX100stores identifier information included in the Extended Identification Packet.

In step S613, the RX200transmits a Configuration Packet to the TX100. The Configuration Packet includes information indicating that a Neg bit is set to 1. When the TX100responds with an ACK Packet in step S614, the RX200transitions to the Negotiation phase, accordingly.

When the RX200transitions to the Negotiation phase, in step S615, the RX200transmits a Specific Request Packet to the TX100. In this example, the RX200designates GP=15 watts in the Specific Request Packet. If the WPC processing unit301of the TX100receives the Packet, in step S616, the WPC processing unit301compares the NFC identifier information designated in step S605, and the identifier information stored in step S612. In this example, the pieces of identifier information match. In step S617, the WPC processing unit301transmits an ACK Packet to the RX200, and allows the GP designated in step S615.

If the Negotiation phase ends, in step S618, the TX100and the RX200transition to the Calibration phase and the Power Transfer phase. The TX100then starts charging processing with respect to the RX200. The TX100performs charging processing with an output that enables the charging unit206of the RX200to receive 15-watt power.

When power reception of the charging unit206ends, in step S619, the RX200transmits an End Power Transfer Packet to the TX100. In step S620, the TX100stops charging processing with respect to the RX200upon receiving the End Power Transfer Packet. In step S621, the RX200is removed from the TX100. In step S622, a response to Polling processing performed by the NFC processing unit302becomes inexecutable. In step S623, the NFC processing unit302thereby detects that the NFC device has withdrawn from the inside of the communication range. In step S624, the NFC processing unit302notifies the WPC processing unit301that NFC identifier information notified in step S605is to be deleted. Upon receiving the notification, the WPC processing unit301deletes the stored NFC identifier information.

FIG.7illustrates an example of a communication sequence between the TX100, the RX200, and an NFC tag that is performed when both of the NFC tag and the RX200including a disabled NFC function are brought closer to the TX100. The RX200may be an apparatus not including an NFC function.

In step S701, the NFC processing unit302of the TX100periodically executes NFC Polling processing similarly to the description forFIG.6. If the NFC tag comes close to the inside of a communication range of communication related to the standard of NFC, a response to Polling is made. In step S702, the NFC processing unit302detects that a device supposed to be an NFC tag has come close. In step S703, the NFC processing unit302reads NFC identifier information from the response to Polling, and notifies the WPC processing unit301of the NFC identifier information.

The processing performed in steps S704to S709is similar to the processing in steps S605to S610illustrated inFIG.6, and therefore the description will be omitted. Nevertheless, the RX200does not transmit an Extended Identification Packet in the processing illustrated inFIG.7. In other words, processing corresponding to the processing of steps S611and S612illustrated inFIG.6is not performed. Further, the processing in steps S710to S712is similar to the processing in steps S613to S615inFIG.6, and thus the description will be omitted.

In step S712, the WPC processing unit301of the TX100receives a Specific Request Packet. In step S713, the WPC processing unit301then compares NFC identifier information designated in step S703and additional identifier information acquired through WPC communication. Since an Extended Identification Packet has not been received in the processing inFIG.7, additional identifier information acquired through WPC communication does not exist. Thus, the NFC identifier information notified from the NFC processing unit302and additional identifier information acquired through WPC communication do not match. In step S714, the WPC processing unit301transmits a NAK Packet to the RX200, and refuses the GP designated in step S712, accordingly.

In step S715, the RX200that has received the NAK Packet transmits a General Request Packet to the TX100, and requests GP value information of the TX100. In step S716, the TX100transmits, to the RX200, a Power Transmitter Capability Packet indicating GP=0.5 watts in response to the General Request Packet.

When the Negotiation phase ends, in step S717, the TX100and the RX200transition to the Calibration phase and the Power Transfer phase, and the TX100starts charging processing with respect to the RX200. The TX100performs charging processing with an output that enables the charging unit206of the RX200to receive 0.5-watt power.

When power reception of the charging unit206ends, in step S718, the RX200transmits an End Power Transfer Packet to the TX100. Upon receiving the End Power Transfer Packet, in step S719, the TX100stops charging processing with respect to the RX200.

Unlike the processing inFIG.6, the NFC processing unit302does not notify the WPC processing unit301that NFC identifier information is to be deleted even if the RX200is removed from the TX100in step S720, because the NFC processing unit302detects an NFC tag. Thereafter, in step S721, the NFC tag is removed from the TX100. In step S722, a response to Polling processing performed by the NFC processing unit302becomes inexecutable. In step S723, the NFC processing unit302thereby detects that the NFC device has withdrawn from the inside of the communication range. In step S724, the NFC processing unit302notifies the WPC processing unit301that NFC identifier information notified in step S703is to be deleted. Upon receiving the notification, the WPC processing unit301deletes the stored NFC identifier information.

(Example of Power Transmission Control in Specific Cases)

Power transmission control in the following cases (1) to (3) will be described.

(1) Case where NFC Tag is Included as NFC Device

An NFC tag makes a response to Polling processing. Furthermore, since the NFC tag does not support the P2P mode, the NFC processing unit302determines that a specific response has been received (YES in step S405). In step S408, the NFC processing unit302subsequently acquires NFC identifier information from the NFC tag, and in step S410, notifies the WPC processing unit301of the acquired NFC identifier information. Furthermore, in step S408, the NFC processing unit302acquires NFC identifier information also from the NFC device, if there is an NFC device that has made a response to Polling processing, in addition to the NFC tag. In step S410, the NFC processing unit302notifies the WPC processing unit301of the acquired NFC identifier information.

In contrast, the NFC tag is not the RX200, and thus the processing illustrated inFIG.8is not performed. The WPC processing unit301therefore does not acquire NFC identifier information of the NFC tag in the WPC processing illustrated inFIG.5. Thus, it is determined as NO in step S516or S522inFIG.5, and the TX100can restrict power transmission. For example, the TX100performs power transmission using only 0.5-watt power indicated by the response transmitted in step S524. Alternatively, power transmission from the TX100may be prevented from being performed.

(2) Case where Only RX Supporting P2P Mode is Included as NFC Device

In this case, an NFC device makes a response to Polling processing using response data including information indicating that the P2P mode is supported, or does not make a response. The NFC device that does not make a response is the RX200operating in the reader/writer mode.

Thus, the NFC processing unit302determines that a specific response has not been received (NO in step S405). In step S406, the NFC processing unit302notifies the WPC processing unit301that a specific NFC device does not exist, accordingly. In step S408, the NFC processing unit302acquires NFC identifier information from an NFC device that has made a response, and in step S410, notifies the WPC processing unit301of the acquired NFC identifier information.

In contrast, since the WPC processing unit301is notified that a specific NFC device does not exist, it is determined as YES in step S515or S522illustrated inFIG.5. The TX100then allows the requested power and power transmission with 15-watt power.

(3) Case where NFC Tag is not Included as NFC Device, and NFC Device not Supporting P2P Mode is Included as NFC Device

This case is further separated in the following manner.

(3-1) Case where Only RX not Supporting P2P Mode and Operating in Card Emulation Mode is Included as NFC Device

In this case, an NFC device makes a response to Polling processing. Nevertheless, the response does not include information indicating that the P2P mode is supported. The NFC processing unit302therefore determines that a specific response has been received (YES in step S405). In step S408, the NFC processing unit302acquires NFC identifier information from the NFC device, and in step S410, notifies the WPC processing unit301of the acquired NFC identifier information.

In contrast, since this NFC device is operating in the card emulation mode, the NFC device notifies the TX100of NFC identifier information (YES in step S805, step S807, and step S808).

The TX100therefore determines as YES in step S515illustrated inFIG.5. Furthermore, the TX100determines as YES in step S516. Alternatively, the TX100determines as YES in step S521illustrated inFIG.5. Furthermore, the TX100determines as YES in step S522. The TX100allows the requested power and power transmission with 15-watt power, accordingly.

(3-2) Case where Both RX not Supporting P2P Mode and Operating in Card Emulation Mode and RX Operating in Reader/Writer Mode are Included as NFC Devices

In this case, while an RX operating in the reader/writer mode does not make a response to Polling processing, an RX operating in the card emulation mode makes a response. Since the response does not include information indicating that the P2P mode is supported, the NFC processing unit302determines that a specific response has been received (YES in step S405). Since no response is received from the RX operating in the reader/writer mode, in step S408, the NFC processing unit302acquires NFC identifier information only from the RX operating in the card emulation mode. In step S410, the NFC processing unit302then notifies the WPC processing unit301of the acquired NFC identifier information.

In contrast, the RX operating in the card emulation mode notifies the TX100of additional identifier information (YES in step S805, step S807, and step S808). Nevertheless, the RX operating in the reader/writer mode does not notify the TX100of additional identifier information (NO in step S805, and step S806).

The TX100therefore acquires the same identifier information from the RX operating in the card emulation mode by using the WPC processing unit301and the NFC processing unit302only. The TX100thus determines as YES in step S515illustrated inFIG.5. Furthermore, the TX100determines as YES in step S516. Alternatively, the TX100determines as YES in step S521illustrated inFIG.5. Furthermore, the TX100determines as YES in step S522. The TX100allows the requested power and power transmission with 15-watt power, accordingly.

(3-3) Case where Only RX not Supporting P2P Mode and Operating in Reader/Writer Mode is Included as NFC Device

Since an RX operating in the reader/writer mode does not make a response to Polling processing, the NFC processing unit302determines that a specific response has not been received (NO in step S405). In step S406, the NFC processing unit302notifies the WPC processing unit301that a specific NFC device does not exist, accordingly. Since an NFC device that has made a response does not exist, the NFC processing unit302does not acquire NFC identifier information.

In contrast, the WPC processing unit301is notified that a specific NFC device does not exist, it is therefore determined as YES in step S515or S522illustrated inFIG.5. The TX100thus allows the requested power and power transmission with 15-watt power.

(Effect)

As described above, by the TX100and the RX200including the above-described configurations, it is possible to protect an NFC tag driven without a battery, and perform high-output power transmission processing with respect to an RX having an NFC module operating in the card emulation mode.

In the above-described exemplary embodiment, an NFC processing unit always stores NFC identifier information of an NFC device that has made a response to Polling. If NFC identifier information becomes nonexistent (YES in step S412), that is to say, if an NFC device is removed, in step S413, the WPC processing unit301is notified of nonexistence of NFC identifier information. In a similar manner, the WPC processing unit301is notified of the resolution when an error of NFC processing has been resolved. With such a configuration, an additional effect can be expected, when an NFC tag is placed on the charging stand of the TX100or an NFC tag is removed from the charging stand while the RX200is performing charging. In other words, GP can be dynamically changed depending on the presence or absence of an NFC tag, and charging can be continued, even when the RX200is performing charging by receiving power from the TX100.

Specifically, the NFC processing unit302notifies the WPC processing unit301that NFC identifier information has become nonexistent, or an error has been resolved, if charging of the RX200is performed in a state in which the TX100restricts GP as described in step S524. The WPC processing unit301then recognizes that a cause for restriction of GP has been resolved, when the WPC processing unit301receives a notification. The TX100therefore transmits a GP re-negotiation request to the RX200, transitions to a Re-negotiation phase defined by the WPC standard, and performs re-negotiation for GP. Since the reason for restriction of GP has been resolved at the time point, in step S523, the TX100can transmit a response indicating that a GP value is the largest power transmission output value defined by the WPC standard, among the capabilities of the power transmitting unit103.

Further, the WPC processing unit301sequentially updates whether an NFC tag exists, and it is therefore possible to avoid restricting GP as the WPC processing unit301erroneously recognizes that an NFC tag exists although an NFC device becomes nonexistent. In addition, it is possible to avoid performing power transmission with high power without restricting GP as the WPC processing unit301erroneously recognizes that an NFC tag does not exist although the NFC processing unit302newly detects an NFC device.

The above-described exemplary embodiment is an example of a typical exemplary embodiment, but the present exemplary embodiment is not limited to the exemplary embodiment described in the specification and the drawings. The present exemplary embodiment may be appropriately implemented in a changed way without departing from the gist thereof.

(Modified Example Related to Identifier Information)

In the present exemplary embodiment, IDm data defined by the standard related to Felica has been exemplified as NFC identifier information exchanged between the TX100and the RX200. Nevertheless, the NFC identifier information is not limited, in the present exemplary embodiment. The NFC identifier information is only required to be information that can uniquely identify a plurality of NFC devices existing within the range of communication based on the standard of NFC of the TX100and WPC communication. For example, the NFC identifier information may be a unique identifier (UID) defined by the standard related to MIFARE®, or may be a media access control (MAC) address or a universally unique identifier (UUID) of an RX.

In addition, a value calculated by hash calculation based on all or a part of NFC Polling response data, or a part at least including identifier information of a transmission source of Polling response data may be used as identifier information. In this case, the TX100performs hash calculation on NFC Polling response data received by the NFC processing unit302, and notifies the WPC processing unit301of the calculated value as identifier information. In contrast, the RX200performs the same hash calculation as the TX100performs on data read as NFC Polling response data, and notifies the TX100of the calculated value through WPC communication.

In addition, the RX200may include identifier information of the RX200defined by the WPC standard, in response data to NFC Polling processing, and the TX100may acquire the identifier information. For example, Extended Device Identifier information included in an Extended Identification Packet may be regarded as response data of NFC Polling.

Further, identifier information notified from the RX200serving as an NFC device in WPC processing may also be identifier information notified from the RX200in an ID Packet. In this case, an Extended Identification Packet may include identifier information notified in an ID Packet, in WPC processing of the RX200.

Identifier information notified from the RX200serving as an NFC device in WPC processing may have the following configuration if the identifier information is identifier information notified from the RX200in an ID Packet. In other words, an Extended Identification Packet may not be notified. In this case, the WPC processing unit301of the TX100may compare identifier information included in an ID Packet notified from the RX200, and NFC identifier information notified from the NFC processing unit302. The NFC identifier information notified from the NFC processing unit302is identifier information included in an ID Packet.

Furthermore, the RX200may perform hash calculation based on all or a part of an Extended Device Identifier, and transmit the calculated value as a NFC Polling response. In this case, the WPC processing unit301of the TX100performs the same hash calculation, as the RX200performs, on identifier information of the RX200included in the received Extended Identification Packet. The TX100may then compare the result of hash calculation and a value received as a Polling response.

The above-described hash calculation is only required to be performed by any one of the NFC processing unit302of the TX100, the WPC processing unit301of the TX100, and another processing unit (not illustrated) of the control unit101.

In the present exemplary embodiment, identifier information of the RX200has been described as Extended Device Identifier information included in an Extended Identification Packet. Nevertheless, identifier information of the RX200may be another piece of identifier information defined by the WPC standard. Specifically, another piece of identifier information may be Basic Device Identifier information included in an Identification Packet. Even when another piece of identifier information is Wireless Power ID (WPID) information included in a Wireless Power Identification Packet defined by the WPC standard, a similar effect can be obtained.

If the RX200operates an NFC function in a plurality of categories (Types A/B/F) defined by the standard of NFC, data obtained by connecting pieces of NFC identifier information that are designated in the respective Types may be used as identifier information. With this configuration, even when the RX200operates the card emulation mode of NFC in a plurality of categories, the TX100can determine whether an identifier acquired in each category is an identifier of the RX200.

In addition, as a method by which the TX100acquires identifier information of the RX200in WPC communication, identifier information may be acquired using another message packet defined by the WPC standard, or an extended message not described in the standard, instead of using a Packet described in the above-described present exemplary embodiment. Furthermore, identifier information of the RX200may be acquired using a communication tool, such as a wireless LAN, Bluetooth®, Zigbee®, Infrared Data Association (IrDA), or a Wireless USB.

(Modified Example Related to NFC Processing)

In the present exemplary embodiment, a method of determining the presence or absence of a response to a Polling request has been described, as a method by which the TX100detects an approaching NFC device. However, a method other than this may be used. Further, it may also be determined whether an approaching NFC device is an NFC tag (or NFC module operating in the card emulation mode) by using additional NFC processing. For example, different message processing of an NFC function may be executed subsequent to Polling processing, and it may be determined whether read data of NFC changes. If the read data changes, it may be determined that the detected NFC device is not an NFC tag. If response data acquired in Polling processing includes an information element indicating that an NFC device is not an NFC tag, it may be determined that the detected NFC device is not an NFC tag. The NFC device determined not to be an NFC tag in this manner is excluded from an NFC device of which identifier information is to be notified to the WPC processing unit301. With this configuration, it becomes possible to perform high-output power transmission processing with respect to the RX200, such as a smartphone, in which processing of transmitting identifier information through WPC communication is not implemented.

In the processing illustrated inFIG.4, the processing in steps S402to S403may be performed after step S405. Specifically, in step S405, whether a specific response to the Polling request (step S401) has been received is determined, and if a specific response has been received (YES in step S405), in step S402, it may be determined whether an error has occurred in the specific response.

In addition, in the processing performed in step S405illustrated inFIG.4, the following two determinations may be separately performed. More specifically, the NFC processing unit302may determine whether a response to the Polling request (step S401) has been received, and if a response has been received, determine whether the response is a response indicating that the P2P mode is not supported. If a response has not been received, and if a response has been received but the response is not a response indicating that the P2P mode is not supported, the NFC processing unit302may perform the processing illustrated in step S406. If a response has been received and the response indicates that the P2P mode is not supported, the processing may proceed to the processing in step S407.

In the above-described present exemplary embodiment, the processing of the NFC processing unit302illustrated inFIG.4is continuously and repeatedly executed while the TX100is in an activated state. Nevertheless, the present exemplary embodiment is not limited to this, and the processing may be started or stopped at a specific timing. For example, the processing illustrated inFIG.4may be executed while the WPC processing unit301detects a nearby object using an Analog Ping. With this configuration, the processing illustrated inFIG.4can be stopped when an object does not exist near the TX100, and power consumption in the TX100can be reduced. Further, the processing illustrated inFIG.4may be executed during a period from when the WPC processing unit301receives a Signal Strength Packet to when an End Power Transfer Packet is received. With this configuration, the processing illustrated inFIG.4can be stopped when an RX having a WPC function does not exist near the TX100, and power consumption in the TX100can be further reduced. Furthermore, a timing at which the TX100starts the processing illustrated inFIG.4may be set to a timing at which the WPC processing unit301is requested to output GP that is equal to or larger than a preset threshold value, by the Specific Request Packet. With this configuration, the TX100executes the processing illustrated inFIG.4only when power transmission processing is executed with an output that might damage an NFC tag, and therefore power consumption in the TX100can be further reduced.

The description has been given of an example in which a program for operating the NFC processing unit302is executed by the control unit101. However, the program may be executed by a different control unit (not illustrated). Specifically, the TX100may be mounted inside a different not-illustrated device (e.g., a printer, personal computer, and mobile battery), and a different control unit that executes a control program of the function of the different device may execute a program for operating the NFC processing unit302.

(Modified Example Related to WPC Processing)

Even in a state in which the TX100does not restrict GP (for example, step S523), charging may be continued in a state in which an NFC tag is not damaged. Specifically, the NFC processing unit302notifies the WPC processing unit301that NFC identifier information has increased, or an error has occurred, while the TX100performs power transmission in a state where GP is not restricted as described in step S523. The WPC processing unit301then recognizes that a cause for restriction of GP has occurred when the WPC processing unit301receives the notification. The TX100therefore transmits a GP re-negotiation request to the RX200, transitions to the Re-negotiation phase defined by the WPC standard, and performs re-negotiation of GP. Since the reason for restriction of GP has occurred at the time point, the TX100can set a power value that does not damage an NFC tag, as GP, and transmit a response indicating the power value. As a configuration in which the TX100transmits a GP re-negotiation request to the RX200, the TX100may notify the RX200that NFC identifier information has become nonexistent or an error has been resolved, and the RX200may transmit a GP re-negotiation request in response to the notification.

A configuration in which the TX100transmits a GP re-negotiation request to the RX200may be the following configuration. That is to say, the TX100may notify the RX200that NFC identifier information has become nonexistent or has increased, or an error has been resolved or occurred, and the RX200may transmit a GP re-negotiation request in response to the notification.

In addition, in the above-described present exemplary embodiment, a power transmission output value, which is determined not to damage an NFC tag even if the TX100performs power transmission processing, is 0.5 watts. However, the power transmission output value may be a different value as long as the power transmission output value does not damage an NFC tag. Specifically, the power transmission output value may be 5 watts defined by the WPC standard as a value of GP when power transmission starts in the Power Transfer phase without transitioning to the Negotiation phase (NO in step S508). The power transmission output value may also be a different value.

(Other Modified Examples)

In the present exemplary embodiment, NFC has been described as an example, but communication is not limited to this. For example, the present exemplary embodiment can be applied even when the RX200includes a communication function of behaving like a tag that performs communication other than NFC, and might be damaged by power transmission with high power.

In the present exemplary embodiment, an NFC device is detected based on a response to Polling processing performed by the second communication unit202. However, the detection of an NFC device is not limited to this. Similarly, the RX200needs not be detected by communication via the first communication unit104. For example, a user of the RX200may notify the TX100that an apparatus being an NFC device and the RX200is placed on the charging stand, via a user interface of the TX100. Even in this case, an NFC tag is sometimes placed on the charging stand, and it is therefore sufficient that the above-described NFC processing or WPC processing is executed.

Other Exemplary Embodiments

A power transmission method of the wireless power transmitting system is not specifically limited. The power transmission method may be a magnetic field resonance method in which power is transmitted by coupling caused by magnetic field resonance between a resonator (resonance element) of a power transmitting apparatus and a resonator (resonance element) of a power receiving apparatus. An electromagnetic induction method, an electric field resonance method, a microwave method, or a power transmission method using laser may also be used.

An exemplary embodiment of the present disclosure can also be implemented by processing of supplying a program for implementing one or more functions of the above-described exemplary embodiment, to a system or an apparatus via a network or a storage medium, and one or more processors in a computer of the system or the apparatus reading and executing the program. Further, an exemplary embodiment of the present disclosure can also be implemented by a circuit (e.g., ASIC) that implements one or more functions.

The power transmitting apparatus and the power receiving apparatus may be an image input apparatus, such as an imaging apparatus (e.g., camera, and video camera) and a scanner, or an image output apparatus, such as a printer, a copying machine, and a projector. The power transmitting apparatus and the power receiving apparatus may also be a storage device, such as a hard disc device and a memory device, or an information processing apparatus, such as a PC and a smartphone.

The flowchart illustrated inFIG.4or5is started when power is supplied to a control unit of a power transmitting apparatus. The processing illustrated inFIG.4or5is implemented by a control unit executing a program stored in a memory of a power transmitting apparatus. The processing illustrated inFIG.8is implemented by a control unit executing a program stored in a memory of a power receiving apparatus.

In addition, at least part of the processing illustrated in the flowchart inFIG.4,5, or8may be implemented by hardware. If hardware is implemented for the implementation, it is sufficient that a dedicated circuit is automatically generated on an FPGA from a program for implementing each step, by using, for example, a predetermined compiler. In addition, similarly to an FPGA, a Gate Array circuit may be formed and implemented as hardware.

The present disclosure is not limited to the above-described exemplary embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present disclosure. The following Claims are therefore appended for setting forth the scope of the present disclosure.

Other Embodiments

Embodiment(s) of the present disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

According to an aspect of the present disclosure, a power receiving apparatus that performs communication based on a standard of NFC can appropriately receive power.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.