Power transmitting device, power receiving device, communication method therebetween, and program

Abstract

To provide a power transmitting device, a power receiving device, and an appropriate communication control method that can execute both in-band communication and out-band communication.SOLUTION: A power transmitting device 100 wirelessly transmitting power to a power receiving device has: a control unit 201 that controls power transmission; a first communication unit 204 that performs communication while superimposing a signal on a power to be transmitted; and a second communication unit 206 that performs communication by using a frequency different from the frequency used for power transmission. When determining to stop the power transmission to the power receiving device while the second communication unit and the power receiving device are connected with each other, based on information transmitted and received between the first communication unit and the power receiving device, the power transmitting device performs communication to connect the second communication unit and the power receiving device to each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In recent years, technical development of wireless power transmission systems has been widely carried out. Patent Document 1 discloses a power transmitting device and a power receiving device that comply with a standard (WPC standard) established by the Wireless Power Consortium (WPC), a standardization organization for wireless power transmission standards. Patent Document 2 describes a method of transmitting and receiving control signals for power transmission and reception in a wireless power transmission system using a frequency / coil or antenna different from the frequency / coil or antenna used for power transmission and reception. Note that communication using a frequency / coil or antenna used for power transmission and reception is called in-band communication, and communication using a frequency / coil or antenna different from the frequency / coil or antenna used for power transmission and reception is called out-band communication. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-56959 A [Patent Document 2] JP 2012-217224 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the WPC standard, power transmission and reception and the associated control communication are performed by magnetic induction. Furthermore, power transmitting devices and power receiving devices that comply with the WPC standard perform control communication using the same frequency as that used for power transmission and reception. In other words, the control communication is in-band communication. In general, the communication range in which in-band communication can be performed without errors is narrower than the communication range of out-band communication. Previously, appropriate communication control in power transmitting devices and power receiving devices that can perform both in-band communication and out-band communication had not been considered.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide an appropriate communication control technique in a power transmitting device and a power receiving device capable of performing both in-band communication and out-band communication. [Means for solving the problem]

[0006] As one means for achieving the above object, a power transmitting device of the present invention has the following configuration. , send An electrical device, comprising: Transmission that transmits wireless power to a power receiving device Means, First communication method A first communication means for performing communication; In the second communication method and a second communication means for performing communication, and in a state in which the second communication means and the power receiving device are connected based on information transmitted and received between the first communication means and the power receiving device, transmission The means for the power receiving device Wireless Power Transmission Stop Stop When the power receiving device is connected to the power supply, the second communication means performs communication for connecting the second communication means and the power receiving device. Effect of the Invention

[0007] According to the present invention, it is possible to appropriately control communication in a power transmitting device and a power receiving device capable of performing both in-band communication and out-band communication. [Brief description of the drawings]

[0008] [Figure 1] 1 shows a configuration example of a wireless power transmission system. [Diagram 2] 2 is a block diagram showing a configuration example of a power transmitting device. FIG. [Diagram 3] 2 is a block diagram showing a configuration example of a power receiving device; [Figure 4] FIG. 2 is a sequence diagram of a power transmitting device and a power receiving device. [Diagram 5] 1 is a diagram for explaining operation timing in a power transmitting device and a power receiving device. [Figure 6A] 10 is a flowchart illustrating an example of a process flow of a power transmitting device. [Figure 6B] 13 is a flowchart showing another example of the processing flow of the power transmitting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] <Embodiment 1> [System configuration] 1 shows an example of the configuration of a wireless power transmission system according to this embodiment. This wireless power transmission system includes a power transmitting device 100 and a power receiving device 101. The power transmitting device 100 and the power receiving device 101 each have a communication function based on BLE (Bluetooth (registered trademark) Low Energy). Hereinafter, a BLE communication unit (a unit formed of a communication circuit, etc.) may be referred to as "BLE".

[0011] In this embodiment, the power transmitting device 100 functions as a BLE Central, and the power receiving device 101 functions as a BLE Peripheral. "Central" indicates a BLE control station, and "Peripheral" indicates a BLE terminal station. A BLE Central communicates with a BLE Peripheral, but does not communicate with other Centrals. A BLE Peripheral communicates with a BLE Central, but does not communicate with other Peripherals. That is, in BLE, communication is not performed between Centrals or between Peripherals. A Central can be in a connected state with multiple Peripherals (BLE CONNECT state), and can transmit and receive data between multiple Peripherals.

[0012] The power transmitting device 100 and the power receiving device 101 may be built into other devices (cameras, smartphones, tablet PCs, laptops, automobiles, robots, medical equipment, printers) and configured to supply power to those devices.

[0013] [Configuration of power transmission device] 2 is a block diagram showing an example of the configuration of the power transmitting device 100. The power transmitting device 100 includes, for example, a control unit 201, a power supply unit 202, a power transmitting unit 203, a first communication unit 204, a power transmitting coil 205, a second communication unit 206, and a memory 207.

[0014] The control unit 201 controls the entire power transmitting device. The control unit 201 can be configured to include one or more processors, such as a central processing unit (CPU) or a micro processing unit (MPU). The control unit 201 may include an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA) configured to execute the processes described below.

[0015] The power supply unit 202 is a power supply that supplies power when at least the control unit 201 and the power transmission unit 203 operate. The power supply unit 202 can be, for example, a wired power receiving circuit that receives power from a commercial power source, a battery, or the like. The power transmission unit 203 generates an AC voltage and an AC current in the power transmission coil 205 in order to transmit power to the power receiving device 101 via the power transmission coil 205 under the control of the control unit 201. The power transmission unit 203 converts the DC voltage supplied by the power supply unit 202 into an AC voltage using, for example, a switching circuit in a half-bridge or full-bridge configuration using a FET (Field Effect Transistor). In this case, the power transmission unit 203 includes a gate driver that controls ON / OFF of the FET.

[0016] The first communication unit 204 performs control communication for wireless power transmission based on the WPC standard with a communication unit (first communication unit 303 shown in FIG. 3) of the power receiving device 101. In this embodiment, the communication performed by the first communication unit 204 is so-called in-band communication in which the AC voltage or current generated by the power transmitting unit 203 is modulated and data (signals) to be communicated are superimposed on the wireless power (power to be transmitted).

[0017] The second communication unit 206 performs control communication for wireless power transmission based on the WPC standard with a communication unit (second communication unit 304 shown in FIG. 3) of the power receiving device 101. The second communication unit 206 performs so-called out-band communication using a frequency different from the frequency (frequency used for power transmission) used by the power transmitting unit 203 for communication, and using an antenna (not shown) different from the power transmitting coil 205. The out-band communication has a higher transmission speed (communication speed) than the in-band communication. By using the out-band communication for control communication, it is possible to speed up the control of the wireless power transmission system. In this embodiment, it is assumed that the second communication unit 206 supports BLE.

[0018] The BLE standard specifies identification information (Bluetooth device identification information: BD_ADDR) of the manufacturer of a product implementing BLE and of the BLE communication unit (in this embodiment, the second communication unit 304, 206). The identification information is expressed by a public address or a random address determined by a random number. The random address includes a static device address, a resolvable private address, and a non-resolvable private address. The static device address is an address generated using a random number generated every time the second communication unit 304, 206 (BLE communication unit) is powered on. The non-resolvable private address is a random number address generated at regular intervals. The resolvable private address is an address generated based on an encryption key exchanged between the Central and the Peripheral.

[0019] In this embodiment, a description will be given assuming that a static device address among random addresses is used as the identification information of the second communication unit 206. However, this is not limited to a static device address, and may be a public address, a resolvable private address, or a non-resolvable private address.

[0020] In addition, in this embodiment, the second communication unit 206 is compatible with BLE, but instead of this, a communication unit compatible with other wireless communication methods such as NFC (Near Field Communication) or WiFi may be used. The communication range of the first communication unit 204 may be narrower than the communication range of the second communication unit 206.

[0021] The memory 207 stores the state of each element of the power transmitting device and the wireless power transmission system, as well as the overall state.

[0022] 2, the control unit 201, the power supply unit 202, the power transmission unit 203, the first communication unit 204, the memory 207, and the second communication unit 206 are each depicted as separate blocks, but two or more of these blocks may be integrated into one chip, etc. Also, one block may be divided into multiple blocks.

[0023] [Configuration of power receiving device] 3 is a block diagram showing an example of the configuration of the power receiving device 101. The power receiving device 101 includes, for example, a control unit 301, a power receiving unit 302, a first communication unit 303, a second communication unit 304, a power receiving coil 305, a charging unit 306, a battery 307, and a memory 308.

[0024] The control unit 301 controls the entire power receiving device 101. For example, the control unit 301 can be configured to include one or more processors such as a CPU or an MPU. 3 01 may include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like configured to perform the processes described below.

[0025] The power receiving unit 302 acquires the AC voltage and AC current generated in the power receiving coil 305 by power transmission from the power transmitting coil 205, and converts the received power into a DC voltage and DC current for operating the control unit 301, the charging unit 306, etc. The first communication unit 303 performs control communication for wireless power transmission based on the WPC standard with the first communication unit 204 of the power transmitting device 100. This control communication is performed by in-band communication that load modulates the electromagnetic waves received by the power receiving coil 305.

[0026] The second communication unit 304 performs control communication of wireless power transmission based on the WPC standard with the second communication unit 206 of the power transmitting device 100. The second communication unit 304 uses a frequency different from the frequency of the electromagnetic waves received by the power receiving unit 302, and performs out-band communication using an antenna (not shown) different from the power receiving coil 305. In this embodiment, the second communication unit 304 is described as being compatible with BLE, and a static device address among random addresses is used as the identification information. However, this is not limited to a static device address, and may be a public address, a resolvable private address, or a non-resolvable private address.

[0027] In this embodiment, the second communication unit 304 is compatible with BLE, but instead of this, a communication unit compatible with other wireless communication methods such as NFC or WiFi may be used. The second communication unit 304 operates by receiving power directly from the power receiving unit 302, but may receive power from a battery 307. The communication range of the first communication unit 303 may be narrower than the communication range of the second communication unit 304.

[0028] The charging unit 306 charges the battery 307 using the DC voltage and DC current supplied from the power receiving unit 302. The memory 308 stores the state of each element of the power receiving device 101 and the wireless power transmission system, as well as the overall state.

[0029] 3, the control unit 301, the power receiving unit 302, the first communication unit 303, the second communication unit 304, the charging unit 306, and the memory 308 are each depicted as separate blocks, but two or more of these blocks may be integrated into one chip, etc. Also, one block may be divided into multiple blocks.

[0030] [Basic operation of power transmitting device and power receiving device] Fig. 4 is a sequence diagram of the power transmitting device and the power receiving device. Basic operations of the power transmitting device 100 and the power receiving device 101 will be described using a part of Fig. 4. It is assumed that the power transmitting device 100 and the power receiving device 101 of this embodiment comply with the WPC standard v1.2.3 and also support out-band communication by BLE. In the following description, data / requests transmitted using General Request defined in the WPC standard are expressed as GRQ(). Data / requests transmitted using Specific Request defined in the same standard are expressed as SRQ().

[0031] The power transmitting device 100 transmits an Analog Ping (hereinafter referred to as A-Ping) to detect an object present near the power transmitting coil 205 (F400). The A-Ping is a pulsed power for detecting an object. Even if the power receiving device 101 receives the A-Ping, the power is so small that it cannot start the control unit 301 of the power receiving device 101. The power transmitting device 100 detects an object by a shift in the resonant frequency of the voltage value inside the power transmitting coil 205 caused by an object present near the power transmitting coil 205, or a change in the voltage value and current value flowing through the power transmitting coil 205.

[0032] When the power transmitting device 100 detects an object by A-Ping, it measures the Q value of the power transmitting coil 205 (F401). A known method may be used for the Q value measurement, and detailed description will be omitted. When the power transmitting device 100 finishes the Q value measurement, it starts transmitting a Digital Ping (hereinafter referred to as D-Ping) (F402). The D-Ping is power for starting the control unit 301 and the second communication unit 304 of the power receiving device 101, and is a power larger than that of the A-Ping. In addition, the D-Ping (F402) is transmitted continuously thereafter. That is, the power transmitting device 100 continues to transmit power equal to or larger than the D-Ping from the start of transmitting the D-Ping until it receives EPT (End Power Transfer) data (signal) from the power receiving device 101 requesting the stop of power transmission.

[0033] When the power receiving device 101 receives a D-Ping and starts up, it transmits Signal Strength, which is data storing the voltage value of the received D-Ping, to the power transmitting device 100 (F403). Next, the power receiving device 101 transmits data storing an ID including version information of the WPC standard to which the power receiving device 101 complies and device identification information (F404). Furthermore, the power receiving device 101 transmits Configuration data to the power transmitting device 100 including information including the maximum value of the power that the power receiving unit 302 supplies to the load (or the charging unit 306) (F405).

[0034] In this example, when the power transmitting device 100 determines that the power receiving device 101 supports the extended protocol of the WPC standard v1.2 or later by receiving the ID and configuration data, the power transmitting device 100 responds with an ACK (F406). The extended protocol is a protocol that includes a negotiation phase, which will be described later.

[0035] When the power receiving device 101 receives the ACK, the power receiving device 101 transitions to a negotiation phase in which negotiations are performed regarding power to be transmitted and received. First, the power receiving device 101 transmits FOD (Foreign Object Detection) Status data to the power transmitting device 100 (F407). In this embodiment, the FOD Status data is expressed as FOD(Q). The power transmitting device 100 performs foreign object detection based on the Q value stored in the received FOD(Q) and the Q value measured in the Q value measurement (F401). In this example, it is assumed that the power transmitting device 100 has determined that there is a high possibility that there is no foreign object, and in this case, transmits an ACK indicating that it has been determined that there is a high possibility that there is no foreign object to the power receiving device 101 (F408).

[0036] When the power receiving apparatus 101 receives the ACK, it transmits a GRQ (CAP) to inquire about the capability of the power transmitting apparatus 100 (F409). When the power transmitting apparatus 100 receives the GRQ (CAP), it transmits capability data (represented as CAP) storing capability information supported by the power transmitting apparatus 100 (F410).

[0037] Next, the power transmitting device 100 and the power receiving device 101 negotiate Guaranteed Power (GP), which is the maximum value of the power value that the power receiving device 101 requests to receive. The Guaranteed Power is the maximum value of the load power of the power receiving device 101 (the power consumed by the charging unit 306) agreed upon in the negotiation between the power transmitting device 100 and the power receiving device 101.

[0038] In this negotiation, first, the power receiving device 101 transmits data (expressed as SRQ(GP)) storing the value of the Guaranteed Power requested by the power receiving device 101 to the power transmitting device 100 (F411). Next, upon receiving the SRQ(GP), the power transmitting device 100 responds to the SRQ(GP) taking into consideration its own power transmission capability and the like. In this example, the power transmitting device 100 determines that the Guaranteed Power is acceptable, and transmits an ACK indicating that the request is accepted (F412). In this example, it is assumed that the power receiving device 101 requests 15 watts as Guaranteed Power in the SRQ(GP), and that the power transmitting device 100 accepts this.

[0039] Next, the power receiving device 101 notifies the power transmitting device 100 of the BD_ADDR (expressed as GRQ(PRX_BD_ADDR)) of the second communication unit 304 (F413). The power transmitting device 100, which has received the GRQ(PRX_BD_ADDR), responds with an ACK (F414). Next, the power receiving device 101 transmits a request (expressed as GRQ(PTX_BD_ADDR_ADDR) (F415)) for notification of the BD_ADDR of the second communication unit 206 of the power transmitting device 100 (F415). Upon receiving the GRQ(PTX_BD_ADDR_ADDR), the power transmitting device 100 notifies the power receiving device 101 of the BD_ADDR (expressed as PTX_BD_ADDR) of the second communication unit 206 (F416).

[0040] Next, the power receiving device 101 transmits a request (SRQ(CONN EIn this example, it is assumed that the power transmitting device 100 intends to perform outband communication by BLE, and in this case, transmits an ACK in response to the received SRQ(CONNECT) (F418).

[0041] When the power receiving device 101 receives the ACK, it transmits a request for ending the negotiation phase (expressed as SRQ(EN)) (F419). The power transmitting device 100 that has received the SRQ(EN) determines whether or not it is acceptable to end the negotiation phase. In this example, the power transmitting device 100 determines to end the negotiation phase and transmits an ACK (F420).

[0042] When the power receiving device 101 receives the ACK, it starts up the second communication unit 304 directly with the power received by the power receiving unit 302, not with the power of the battery 307. Then, the power receiving device 101 broadcasts an ADVERTISE_INDICATION (hereinafter, referred to as ADV) using the second communication unit 304 (F421). ADV is a signal defined in the BLE standard. ADV is a signal broadcast by a device in an Advertiser state defined in the BLE standard, and is used to notify the BD_ADDR of the device and information on supported services.

[0043] When the power transmitting device 100 transmits the ACK (F420), the power transmitting device 100 starts the second communication unit 206 as a scanner and waits for an ADV. In this example, before a predetermined time during which the second communication unit 206 of the power transmitting device 100 operates as a scanner elapses, the power transmitting device 100 receives an ADV including the BD_ADDR received in F413 by in-band communication from the power receiving device 101. In this case, the power transmitting device 100 operates the second communication unit 206 as an initiator defined in the BLE standard. The second communication unit 206 operating as the initiator transmits a Connect_indication (hereinafter referred to as CONNECT), which is a BLE connection request message, to the received BD_ADDR (F422). Thereafter, the control communication between the power transmitting device 100 and the power receiving device 101 is performed using BLE (i.e., the second communication unit 206 and the second communication unit 304).

[0044] The power transmitting device 100 and the power receiving device 101 perform a calibration process to create a reference for performing foreign object detection based on the power loss method. First, the power receiving device 101 transmits a Received Power Packet (mode1) ( RP 1) to the power transmitting device 100 (F423).

[0045] Upon receiving RP1, the power transmitting apparatus 100 transmits an ACK to the power receiving apparatus 101 (F424). At this time, the power transmitting apparatus 100 measures its own transmission power value T1, and calculates the difference Δ1 between T1, which is the power loss, and R1.

[0046] The power receiving device 101 that has received the ACK connects the power receiving unit 302 to a load and supplies the received power to the load, and requests the power transmitting device 100 to increase or decrease the receiving voltage (or receiving current, receiving power) according to the load. This request is made by transmitting a Control Error (hereinafter referred to as CE) to the power transmitting device 100. CE stores information on a sign and a value. If the sign of the value stored in CE is positive, it indicates a request to increase the receiving voltage, if it is negative, it indicates a request to decrease the receiving voltage, and if the value is zero, it indicates that the receiving voltage is to be maintained. Here, the power receiving device 101 transmits CE(+), which indicates an increase in the receiving voltage, to the power transmitting device 100 (F425).

[0047] When the power transmitting device 100 receives CE(+), it changes the setting value of the power transmitting circuit and increases the power transmission voltage. When the power receiving device 101 responds to CE(+) and the received power increases, it supplies the received power to the charging unit 306, which is a load, and transmits RP2 (Received Power Packet (mode 2)) to the power transmitting device 100 (F426). Here, RP2 stores a received power value R2 in a state in which the power receiving device 101 supplies the output of the power receiving unit 302 to the load (charging unit 306).

[0048] When the power transmitting device 100 receives RP2, it transmits an ACK to the power receiving device (F427). At this time, the power transmitting device 100 measures its own transmission power value T2, and calculates the difference Δ2 between T2 and R2, which is the power loss. Next, the power transmitting device 100 performs foreign object detection based on the power loss, using the power loss Δ1 (the power loss when the power receiving unit 302 is not connected to a load and the load's power consumption is zero) and the power loss Δ2 (the power loss when the power receiving unit 302 is connected to a load and the load's power consumption is not zero) as references. Specifically, the power transmitting device 100 predicts the power loss in a state where there is no foreign object at any received power value from Δ1 and Δ2, and can perform foreign object detection based on the actually received power value (RP0 described later) and the transmitted power value at that time.

[0049] The calibration process is completed as described above. Note that the calibration process ends when the power transmitting device 100 transmits an ACK to RP2. Also, when the power receiving device 101 receives an ACK to RP1, the power transmitting device 100 and the power receiving device 101 have transitioned to the Power Transfer phase, and the power transmitting device 100 transmits the maximum 15 watts of power that the power receiving device negotiated in the Negotiation phase can receive.

[0050] The power receiving apparatus 101 periodically transmits to the power transmitting apparatus 100 a Received Power Packet (mode 0) (RP0) that stores a CE and a current received power value (F428). Power transmitting device 100 responds with an ACK (F429) .

[0051] The above is a description of the basic operations of the power transmitting device 100 and the power receiving device 101. Even if the power transmitting device 100 receives an ADV in F421 from a source of a BD_ADDR other than the BD_ADDR received by in-band communication in F413, the power transmitting device 100 does not transmit a CONNECT to the source of the ADV. In this manner, the power transmitting device 100 can establish a BLE connection only with the power receiving device 101.

[0052] Furthermore, when the power receiving device 101 receives a CONNECT from a source of a BD_ADDR other than the BD_ADDR received by in-band communication in F416, the power receiving device 101 transmits an LL_TERMINATE_IND (hereinafter, referred to as TERM) indicating that the BLE connection is to be terminated to the source of the CONNECT. In this manner, the power receiving device 101 can accept only connection requests from the power transmitting device 100.

[0053] [Operation timing in conventional power transmitting device and power receiving device] Next, the operation timing in the conventional power transmitting device and power receiving device will be described. Fig. 5 is a diagram for explaining the operation timing in the power transmitting device and power receiving device, and Fig. 5(a) and Fig. 5(b) are diagrams for explaining the operation timing in the conventional power transmitting device and power receiving device. Here, the explanation will be given using the power transmitting device 100 and the power receiving device 101. It is assumed that the power transmitting device 100 and the power receiving device 101 have completed the steps F400 to F420 shown in Fig. 4. That is, it is assumed that the first communication unit 204 of the power transmitting device 100 transmits and receives information including information for communication by the second communication unit 206 with the power receiving device 101, and the second communication unit 206 is in a state in which it can receive the ADV (F421) from the power receiving device 101.

[0054] In FIG. 5(a), the second communication unit 304 of the power receiving device 101 broadcasts ADV 507 at time T1 in ADVERTISING state 500 in which the power receiving device 101 operates as an Advertiser (F421). The second communication unit 206 of the power transmitting device 100 can receive ADV 507 in SCANNING state 502 in which the power transmitting device 100 operates as a Scanner. Upon receiving ADV 507, the second communication unit 206 of the power transmitting device 100 transitions to INITIATING state 503 in which a BLE connection process is performed, and transmits CONNECT 508 to the power receiving device 101 (F422). The second communication unit 206 of the power transmitting device 100 transmits a CONNECT 508 When the second communication unit 304 of the power receiving device 101 receives a CONNECT 508 from the power transmitting device 100, the second communication unit 304 of the power receiving device 101 transitions to the CONNECTION state 501.

[0055] 5(b), when the second communication unit 206 of the power transmitting device 100 and the second communication unit 304 of the power receiving device 101 are in the CONNECTION state 501, it is assumed that the second communication unit 304 of the power receiving device 101 transmits an EPT (Re-ping) 509 defined in the WPC standard to the power transmitting device 100. EPT stands for End Power Transfer, and is data requesting the stop of power transmission. Re-Ping means that power transmission is stopped for a certain period (Re-Ping time), but a D-Ping is transmitted again after a predetermined time.

[0056] After receiving the EPT (Re-Ping) 509, the power transmitting device 100 decides to stop power transmission to the power receiving device 101, and stops the power transmission within time T_terminate. Here, it is assumed that the power transmitting device 100 stops power transmission at time T3. Since the second communication unit 304 of the power receiving device 101 operates using the power received by the power receiving unit 302, not the power of the battery 307, the power transmitting device 100 ends the CONNECTION state 501 at time T3 when the power transmitting device 100 stops power transmission. 304 When the power receiving device 101 ends the CONNECTION state 501, the power receiving device 101 does not transmit any data to the power transmitting device 100. Since the second communication unit 304 of the power receiving device 101 is powered on again when communication is resumed, the BD_ADDR may change.

[0057] The second communication unit 206 of the power transmitting device 100 has a timer defined by the BLE standard to determine whether or not the BLE connection with the second communication unit 304 of the power receiving device 101 has been disconnected (link loss). This timer is called a supervision timer, and the timeout period is expressed as T_sv_to 506 in this embodiment. Note that according to the BLE standard, the timeout period is 20 seconds by default.

[0058] If the second communication unit 206 of the power transmitting device 100 does not receive any data from the second communication unit 304 of the power receiving device 101 during T_sv_to, the second communication unit 206 ends the CONNECTION state 501. In this embodiment, it is assumed that T_sv_to starts at time T3 and times out at time T7.

[0059] When the power transmitting device 100 ends power transmission at time T3 and a predetermined power transmission suspension period (Re-Ping time, default 500 milliseconds in the WPC standard) ends, the first communication unit 204 transmits D-Ping 510 again at time T4. The power receiving device 101 receives D-Ping 510 by the first communication unit 303 and starts up the second communication unit 304. After the procedure from F403 to F420 in Fig. 4, the second communication unit 304 of the power receiving device 101 broadcasts ADV 507 at time T5 (F421) in the ADVERTISING state 500 that continues until time T6.

[0060] At time T5, the Supervision timer in the power transmitting device 100 has not timed out, so the second communication unit 206 of the power transmitting device 100 is in the CONNECTION state 501. That is, the second communication unit 206 of the power transmitting device 100 is not in the SCANNING state 502, so it cannot receive the ADV 507 transmitted at time T5. Therefore, the second communication unit 304 of the power receiving device 101 cannot enter the CONNECTION state 501, and cannot perform control communication by BLE thereafter. On the other hand, when the above-mentioned T_sv_to times out at time T7, the second communication unit 206 of the power transmitting device 100 enters a state in which it can transition to the SCANNING state 502 to the INITIATING state 503. However, this time, the second communication unit 304 of the power receiving device 101 has ended the ADVERTISING state 500 at time T6. Therefore, the second communication unit 206 of the power transmitting device 100 cannot receive the ADV (F421).

[0061] Thus, conventionally, when the second communication unit 304 of the power receiving device 101 is in the ADVERTISING state, the second communication unit 206 of the power transmitting device 100 cannot transition to the SCANNING state or the INITIATING state. Therefore, the power transmitting device 100 in this embodiment operates as follows.

[0062] [Processing of the power transmission device in this embodiment] 6A shows a flowchart illustrating an example of a process flow of the power transmitting device 100 in this embodiment. As shown on the left side of FIG. 5B, this flow can be started when the second communication unit 206 of the power transmitting device 100 receives an EPT from the power receiving device while the second communication unit 206 is in the CONNECTION state 501.

[0063] When the second communication unit 206 of the power transmitting device 100 receives an EPT from a power receiving device (S600), the control unit 201 determines whether the reason code included in the EPT is Re-Ping (S601). If the reason code is Re-ping (YES in S601), the process proceeds to S602, and if the reason code is not Re-ping (No in S601), the process ends. In S602, the control unit 201 determines whether the second communication unit 206 is connected to any power receiving device via BLE. If the second communication unit 206 is connected to any power receiving device via BLE (Yes in S602), the second communication unit 206 transmits TERM to the power receiving device (S603). As described above, TERM is LL_TERMINATE_IND indicating that the BLE connection is to be disconnected. After transmitting TERM, the power transmitting device 100 stops power transmission, and the second communication unit 206 becomes capable of transitioning to the SCANNING state 502 to the INITIATING state 503. On the other hand, if the second communication unit 206 is not connected to any power receiving device via BLE (No in S602), the process ends.

[0064] Next, the operation of the power transmitting device 100 and the power receiving device 101 that operate based on the flow of Fig. 6A will be described. Fig. 5(c) is a diagram for explaining the operation timing of the power transmitting device 100 and the power receiving device 101 that operate based on the flow of Fig. 6A. Also refer to the processing after F430 in Fig. 4.

[0065] When the second communication unit 206 of the power transmitting device 100 and the second communication unit 304 of the power receiving device 101 are in the CONNECTION state 501, the second communication unit 206 of the power transmitting device 100 receives an EPT (Re-Ping) 509 from the power receiving device 101 at time T8 (F430). Since the second communication unit 206 is connected to the second communication unit 304 of the power receiving device 101 by BLE, it transmits a TERM 511 at time T9 (F431). Thereafter, the power transmitting device 100 stops transmitting power. Then, at time T10 after the Re-ping time has elapsed, the first communication unit 204 of the power transmitting device 100 transmits a D-Ping 510 again (F432). The power receiving device 101 receives the D-Ping 510 via the first communication unit 303 and starts up the second communication unit 206. After the procedure (F433) from F403 to F420 in FIG. 4, the second communication unit 304 of the power receiving apparatus 101 broadcasts ADV 507 at time T11 (F434).

[0066] Since the second communication unit 206 of the power transmitting device 100 transmits TERM at time T9, the state transitions from SCANNING state 502 to INITIATING state 503 after time T9. That is, the state transitions to SCANNING state 502 after time T9, and the second communication unit 206 of the power transmitting device 100 transitions to a state in which it can receive ADV as information necessary for connection with the second communication unit 304 of the power receiving device 101. Then, at time T11, the second communication unit 206 of the power transmitting device 100 receives ADV transmitted from the second communication unit 304 of the power receiving device 101, and then transmits CONNECT 508 in the INITIATING state 503 at time T12 (F435).

[0067] As described above, the power transmitting device 100 of the present embodiment can use the second communication unit 206 to establish a BLE connection with the power receiving device again when power transmission is resumed after power transmission has been stopped.

[0068] <Variation 1> In the example of FIG. 5(c), when the second communication unit 206 of the power transmitting device 100 receives an EPT (Re-Ping) 509, the second communication unit 206 transmits a TERM 511 before stopping power transmission. Alternatively, the second communication unit 206 may transmit a TERM after stopping power transmission. For example, the power transmitting device 100 may stop power transmission at time T9, and the second communication unit 206 may transmit a TERM while the first communication unit 204 starts transmitting a D-Ping again at time T10. Alternatively, the second communication unit 206 may transmit a TERM from when the first communication unit 204 starts transmitting a D-Ping again at time T10 until the second communication unit 206 receives an ADV at time T11.

[0069] <Variation 2> 6B shows a flowchart illustrating another example of the processing flow of the power transmitting device 100 in this embodiment. This flow can be started when the second communication unit 206 of the power transmitting device 100 is in the CONNECTION state 501, as shown on the left side of FIG.

[0070] When the first communication unit 204 of the power transmitting device 100 receives a BD_ADDR from the power receiving device through in-band communication (S611), the process proceeds to S612. In S612, the control unit 201 determines whether the second communication unit 206 is connected to any power receiving device through BLE. If the second communication unit 206 is connected to any power receiving device through BLE ( S612If the answer is Yes in S612, the control unit 201 decides to stop power transmission to the power receiving device. Then, the second communication unit 206 transmits TERM to the power receiving device (S613). With reference to FIG. 5(c), TERM can be transmitted at time T9, but the second communication unit 206 may transmit TERM at time T12 before transmitting CONNECT 508 to the BD_ADDR received by in-band communication. On the other hand, if the second communication unit 206 is not connected to any power receiving device via BLE (No in S612), the process ends.

[0071] In this way, when the BD_ADDR changes due to reasons such as the power receiving device being powered on again, the BD_ADDR can be transmitted to the power transmitting device via in-band communication, and the power transmitting device and the power receiving device can attempt to connect via BLE again.

[0072] <Variation 3> 5(c), the second communication unit 206 of the power transmitting device 100 transmits TERM. Alternatively, the second communication unit 304 of the power receiving device 101 may transmit TERM at the same timing as that already described. For example, when the control unit 301 of the power receiving device 101 decides to request the power transmitting device 100 to stop receiving power for some reason, the second communication unit 304 may transmit TERM to the power transmitting device 100.

[0073] <Modification 4> The power transmitting device 100 may set a timeout time (T_sv_to) of a supervision timer for determining whether or not a BLE connection with the power receiving device 101 has been disconnected (link loss) according to the Re-Ping time. For example, the power transmitting device 100 may set T_sv_to to be shorter than the Re-Ping time.

[0074] 5(d) is a diagram for explaining the operation timing of the power transmitting device 100 and the power receiving device 101 operating in this way. When the second communication unit 206 of the power transmitting device 100 and the second communication unit 304 of the power receiving device 101 are in the CONNECTION state 501, the second communication unit 206 of the power transmitting device 100 receives an EPT (Re-Ping) 509 from the power receiving device 101. Thereafter, the power transmitting device 100 stops power transmission at time T13. Then, at time T15 after the Re-ping time (T_reping 505 in the figure) has elapsed, the first communication unit 204 of the power transmitting device 100 transmits a D-Ping 510 again. Here, the power transmitting device 100 sets T_sv_to 506 to a time shorter than T_reping 505. Then, at time T14, the Supervision timer times out, and the second communication unit 206 of the power transmitting device 100 transitions to the SCANNING state or the INITIATING state, and becomes able to receive ADV and transmit CONNECT.

[0075] <Variation 5> In the above description, the power transmitting device 100 functioning as a BLE Central determines and sets the timeout time (T_sv_to) of the Supervision timer to a value corresponding to the Re-Ping time. Alternatively, the power receiving device 101 functioning as a BLE Peripheral may determine the timeout time (T_sv_to) to a value corresponding to the Re-Ping time and request the power transmitting device 100 to set the timeout time to the value. This request can be made by transmitting a BLE packet including LL_CONNECTION_PARAM_REQ or a command L2CAP_CONNECTION_PARAMETER_UPDATE_REQ of the BLE standard to the power transmitting device 100. The power receiving device 101 transmits a BLE packet at any timing during the period of the CONNECTION state 501 in FIG. 5(d). When the power transmitting device 100 receives the BLE packet, it sets the timeout time (T_sv_to) included in the BLE packet.

[0076] The control unit 201 of the power transmitting device 100 uses an OS (Operating System), which is basic software, to perform BLE communication. Due to the constraints of this OS, the power transmitting device 100 may not be able to determine the timeout time of the Supervision timer to a value desired by the power transmitting device 100. In such a case, by doing as described above, it is possible to set the timeout time (T_sv_to) of the Supervision timer to a value corresponding to the Re-Ping time. In this way, one of the power transmitting device 100 and the power receiving device 101 determines the timeout time and sets the timeout time to the other by transmitting a signal that can identify the timeout time. In this way, even if one device cannot determine the timeout time due to constraints of the OS, it is possible to set the timeout time according to the Re-Ping time.

[0077] <Variation 6> In the above description, an example in which the power transmitting device 100 receives an EPT including the reason code: Re-Ping (EPT(Re-Ping)) has been described as an example in which the power transmitting device 100 decides to stop / interrupt power transmission, but other reason codes may be used. For example, the power transmitting device 100 may interrupt power transmission when it receives data including another reason code intended to interrupt power transmission. Furthermore, the power transmitting device 100 may decide to stop / interrupt power transmission when the control unit 201 detects a foreign object due to power transmitted under the control of the control unit 201.

[0078] <Variation 7> A modified example will be described in which the second communication unit 206 of the power transmitting device 100 has a Central function that allows simultaneous connection with multiple Peripherals. In this case, the power transmitting device 100 has a function of maintaining the SCANNING state even during a period in which the power transmitting device 100 is in the CONNECTION state or the INITIATING state with a certain power receiving device 101, receiving an ADV from another power receiving device 101, and connecting to the other power receiving device 101 via BLE.

[0079] In the description of FIG. 6A, when the second communication unit 206 of the power transmitting device 100 is connected to any power receiving device via BLE (Yes in S602), the second communication unit 206 transmits TERM to the power receiving device (S603). That is, the condition in S602 is that the power transmitting device is connected to one power receiving device via BLE. Alternatively, the condition in S602 may be that the power transmitting device is connected to N (N≧2) or more power receiving devices via BLE. In this case, the destination to which TERM is transmitted in S603 is the power receiving device that is the source of the EPT received by in-band communication in S600.

[0080] In this way, the power transmitting device 100 can continue to use the BLE connection with the power receiving device 101 in applications other than out-of-band communication for power transmission control after stopping power transmission to the power receiving device 101. Even in this case, power transmission and BLE connection can be performed to a predetermined number or more power receiving devices other than the power receiving device 101.

[0081] <Variation 8> In the above description, the power transmitting device 100 operates as a BLE Central, and the power receiving device 101 operates as a BLE Peripheral. Alternatively, the power transmitting device 100 may operate as a Peripheral, and the power receiving device 101 may operate as a Central.

[0082] <Embodiment 2> In this embodiment, the power transmitting device 100 performs BLE connection and power transmission to a certain power receiving device 101 (referred to as power receiving device A), and then performs power transmission and BLE connection to another power receiving device 101 (referred to as power receiving device B). This mode may occur, for example, when the power receiving device A is removed by the user and replaced with the power receiving device B.

[0083] FIG. 5(e) is a diagram for explaining operation timings of the power transmitting device, the power receiving device A, and the power receiving device B in this embodiment.

[0084] When the second communication unit 206 of the power transmitting device 100 and the second communication unit 304 of the power receiving device A are in the CONNECTION state 501, the second communication unit 206 of the power transmitting device 100 receives an EPT (Re-Ping) 509 from the power receiving device A at time T8. Since the second communication unit 206 is connected to the second communication unit 304 of the power receiving device A by BLE, it transmits a TERM 511 at time T9. Thereafter, the power transmitting device 100 stops transmitting power. Here, between time T9 and time T10, the power receiving device A is removed by the user and replaced with the power receiving device B. Then, at time T10 after the Re-ping time has elapsed, the first communication unit 204 of the power transmitting device 100 transmits a D-Ping 510 again. The power receiving device B receives the D-Ping 510 by the first communication unit 303 and starts the second communication unit 206. After the procedure (F433) from F403 to F420 in FIG. 4, the second communication unit 304 of the power receiving device B broadcasts ADV507 at time T11.

[0085] Since the second communication unit 206 of the power transmitting device 100 transmits TERM at time T9, the state transitions from the SCANNING state 502 to the INITIATING state 503 after time T9. That is, the state transitions to the SCANNING state 502 after time T9, and the second communication unit 206 of the power transmitting device 100 transitions to a state in which it can receive an ADV as information required for connection with the second communication unit 304 of the power receiving device B. Then, at time T11, the second communication unit 206 of the power transmitting device 100 receives the ADV transmitted from the second communication unit 304 of the power receiving device B. It can be confirmed that the ADV is from the power receiving device B by checking whether the BD_ADDR included in the ADV matches the BD_ADDR received by in-band communication at F413. If they match, the power transmitting device 100 transmits CONNECT 508 at time T12 in the INITIATING state 503.

[0086] As described above, when the power transmitting device 100 of the present embodiment starts power transmission to the power receiving device B after stopping power transmission to the power receiving device A, it can establish a BLE connection with the power receiving device B.

[0087] <Variation 9> In the example of FIG. 5(e), when the power transmitting device 100 receives an EPT (EPT(Re-Ping) 509) including a reason code: Re-Ping, the power transmitting device 100 transmits TERM 511 before stopping power transmission. Alternatively, the power transmitting device 100 may perform a similar process when it receives an EPT including a reason code indicating completion of charging. In this manner, the power transmitting device 100 can transmit power to and establish a BLE connection with the power receiving device B even when the user replaces the power receiving device A with the power receiving device B after completing charging of the power receiving device A.

[0088] <Modification 10> In the example of FIG. 5(e), the power transmitting device 100 transmits D-Ping 510 at time T10. Alternatively, A-Ping may be repeatedly transmitted from time T10, and D-Ping 510 may be transmitted after an object is detected. In this manner, the power transmitting device 100 can transmit power to the power receiving device B and establish a BLE connection even if a period of time elapses between when the power receiving device A is removed and when the power receiving device B is placed. Note that the above process may be performed when an EPT including a reason code other than Re-Ping, for example, a reason code indicating completion of charging, is received.

[0089] <Modification 11> In the example of FIG. 5(e), when the power transmitting device 100 receives EPT (Re-Ping) 509, it transmits TERM 511 before stopping power transmission. Instead of this, the power transmitting device 100 may perform a similar process when it is not possible to continuously receive CE or RP0 from the power receiving device A for a predetermined time or more. The predetermined time is a time that exceeds the transmission interval of CE or RP0 by the power receiving device 101, as defined by the WPC standard. By transmitting power to the power receiving device B and establishing a BLE connection thereto when there is a time between when the power receiving device A is removed and when the power receiving device B is placed, the power transmitting device 100 can transmit power to the power receiving device B and establish a BLE connection thereto even when the power receiving device A is removed and replaced with the power receiving device B during power transmission to the power receiving device A in the Power Transfer phase.

[0090] <Modification 12> As in variant example 4, the power transmitting device 100 of this embodiment may set the timeout time (T_sv_to) of the supervision timer for determining whether the BLE connection with the power receiving device 101 has been disconnected (link lost) according to the Re-Ping time.

[0091] 5(f) is a diagram for explaining the operation timing of the power transmitting device 100 operating in this way, and the power receiving device A and the power receiving device B. When the second communication unit 206 of the power transmitting device 100 and the second communication unit 304 of the power receiving device A are in the CONNECTION state 501, the second communication unit 206 of the power transmitting device 100 receives an EPT (Re-Ping) 509 from the power receiving device A. Thereafter, the power transmitting device 100 stops power transmission at time T13. Here, between time T13 and time T15, the power receiving device A is removed by the user and replaced with the power receiving device B. Then, at time T15 after the Re-ping time (T_reping 505 in the figure) has elapsed, the first communication unit 204 of the power transmitting device 100 transmits a D-Ping 510 again. The power receiving device B receives D-Ping 510 via the first communication unit 303 and activates the second communication unit 206. After the procedure (F433) from F403 to F420 in FIG. 4, the second communication unit 304 of the power receiving device B broadcasts ADV 507 at time T11. Here, the power transmitting device 100 sets T_sv_to 506 to a time shorter than T_reping 505. Then, the Supervision timer times out at time T14, and the second communication unit 206 of the power transmitting device 100 transitions to the SCANNING state or the INITIATING state, and becomes able to receive the ADV transmitted by the power receiving device B and transmit CONNECT.

[0092] <Other embodiments> The processes shown in Fig. 6A and Fig. 6B above can be realized, for example, by the control unit 201 of the power transmitting device 100 reading and executing a program stored in advance to control each functional unit. However, this is not limited to this, and at least a part of these processes may be realized by hardware. When realizing by hardware, for example, by using a predetermined compiler, a dedicated circuit can be automatically generated on an FPGA (Field Programmable Gate Array) from a program for realizing each processing step. Also, a gate array circuit may be formed in the same manner as the FPGA, and hardware that executes at least a part of the above-mentioned processes may be realized.

[0093] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0094] The above-mentioned embodiments and modifications can be implemented in any combination. The invention is not limited to the above-mentioned embodiments, and various modifications and variations can be made without departing from the spirit and scope of the invention. Therefore, the following claims are appended to clarify the scope of the invention. [Explanation of symbols]

[0095] 100 Power transmitting device, 101 Power receiving device

Claims

1. A power transmission device, A transmission means for performing wireless power transmission to a power receiving device; A first communication means for performing communication in a first communication method; A second communication means for performing communication in a second communication method, A power transmitting device characterized in that when the second communication means and the power receiving device are connected based on information transmitted and received between the first communication means and the power receiving device, and the transmission means stops wireless power transmission to the power receiving device, the second communication means performs communication to connect the second communication means and the power receiving device.

2. the second communication method is a communication method conforming to the Bluetooth standard, The power transmitting device of claim 1, characterized in that when the second communication means is connected to the power receiving device based on information transmitted and received between the first communication means and the power receiving device and the transmission means stops wireless power transmission to the power receiving device, the second communication means transitions to a state in which it can receive a signal defined by the Bluetooth standard that is broadcast from the power receiving device, and the second communication means performs communication to connect to the power receiving device.

3. A power transmission device as described in Claim 2, characterized in that when the transmission means stops wireless power transmission to the power receiving device while the second communication means is connected to the power receiving device based on information transmitted and received between the first communication means and the power receiving device, the second communication means transmits a signal to the power receiving device indicating that the connection with the power receiving device is to be severed.

4. 4. The power transmitting device according to claim 2, wherein the transmission means stops wireless power transmission to the power receiving device when the second communication means receives a signal from the power receiving device requesting that wireless power transmission be stopped.

5. 4. The power transmitting device according to claim 2, wherein the transmitting means stops wireless power transmission to the power receiving device when the first communication means receives identification information of a Bluetooth device.

6. 3. The power transmitting device according to claim 2, wherein the second communication means transitions to a state in which it can receive a signal defined by the Bluetooth standard when a Supervision timer times out in a Bluetooth connection with the power receiving device.

7. 7. The power transmitting device according to claim 6, wherein a timeout period of the Supervision timer is determined by one of the power transmitting device and the power receiving device, and is set in the other device by transmitting a signal capable of identifying the timeout period.

8. A power receiving device, A power receiving means for wirelessly receiving power from a power transmitting device; A control means for controlling wireless power reception; A first communication means for performing communication in a first communication method; A second communication means for performing communication in a second communication method, A power receiving device characterized in that when the second communication means and the power transmitting device are connected based on information transmitted and received between the first communication means and the power transmitting device, and the control means determines to request the power transmitting device to stop the wireless power reception, the second communication means performs communication to connect the second communication means and the power transmitting device.

9. the second communication method is a communication method conforming to the Bluetooth standard, The power receiving device described in claim 8, characterized in that when the second communication means is connected to the power receiving device based on information transmitted and received between the first communication means and the power receiving device, and the control means decides to request the power transmitting device to stop the wireless power reception, the second communication means transmits a signal to the power transmitting device indicating that the connection with the power transmitting device is to be disconnected.

10. A communication method for a power transmission device having a first communication means for communicating by a first communication method and a second communication means for communicating by a second communication method, wirelessly transmitting power to a power receiving device; stopping wireless power transmission to the power receiving device in a state in which the second communication means and the power receiving device are connected based on information transmitted and received between the first communication means and the power receiving device; A communication method comprising: when wireless power transmission to the power receiving device is stopped, performing communication to connect the second communication means and the power receiving device via the second communication means.

11. A communication method for a power receiving device having a first communication means for communicating by a first communication method and a second communication means for communicating by a second communication method, wirelessly receiving power from a power transmitting device; determining whether to request the power transmitting device to stop the wireless power reception in a state in which the second communication means and the power transmitting device are connected based on information transmitted and received between the first communication means and the power transmitting device; A communication method comprising: when it is determined that the power transmission device should be requested to stop the wireless power reception, performing communication to connect the second communication means and the power transmission device using the second communication means.

12. A program for causing a computer to function as the power transmitting device according to claim 1 .

13. A program for causing a computer to function as a power receiving device as described in claim 8 or 9.

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