Device, method performed by device for wireless power transmission, and program

Abstract

This device for wireless power transmission includes: power transmission means for wirelessly transmitting power; power reception means for wirelessly receiving power; and selection means for selecting either a first state in which the power transmission means operates or a second state in which the power reception means can operate. The selection means switches from the second state to the first state on the basis of the time during which the second state is continuous.

Description

Device, Method and Program Performed by a Device for Wireless Power Transmission

[0001] The present disclosure relates to wireless power transmission.

[0002] In recent years, the technological development of wireless power transmission systems has been widely carried out. In Patent Document 1, a power transmission device and a power reception device compliant with the standard (hereinafter referred to as the "Qi standard") formulated by the Wireless Power Consortium (hereinafter referred to as "WPC"), a non-contact charging standard standardization organization, are disclosed.

[0003] Recently, a power transmission / reception device having both a power transmission device and a power reception device has also been widely popularized. The power transmission / reception device is a device having both sides of a power reception device and a power transmission device, and is, for example, a smartphone, a tablet, a portable charger, etc. equipped with a large-capacity battery. Among power transmission / reception devices, especially in the case of a device capable of wireless power transmission, a user operates a UI (User Interface) to change the settings of the power transmission / reception device, and places another power reception device at a predetermined position of the power transmission / reception device to start wireless power transmission.

[0004] Furthermore, in Japanese Unexamined Patent Application Publication No. 2017-85855, in order to reduce the user operations required for the wireless power transmission settings of the power transmission / reception device, a charging adapter having a power transmission means for performing wireless power transmission is used, and a control device for controlling the operation mode of the power transmission / reception device is disclosed. More specifically, the power transmission target device detects that the power transmission target device is placed on the charging adapter, and notifies the power transmission / reception device of the detection result by wireless communication. When the power transmission / reception device receives the notification, it controls the operation mode of the USB (Universal Serial Bus) connecting the power transmission / reception device and the charging adapter so that it can perform wireless power transmission to the power transmission target device placed on the charging adapter. Note that Japanese Unexamined Patent Application Publication No. 2017-85855 describes wireless power transmission from the power transmission / reception device, but does not provide a detailed explanation about wireless power transmission to the power transmission / reception device.

[0005] Furthermore, Japanese Patent Publication No. 2018-153043 also discloses a proposal regarding the switching of the operating mode of a power transmission and reception device. The technology related to this proposal involves switching the operating mode from a power reception mode, in which power is received from another power supply device, to a power supply mode, or not switching, based on communication established between the power transmission and reception device and an external device.

[0006] As described above, for a power transmission / reception device to change its operating mode, the user needs to change the wireless power transmission settings of the device, use an accessory such as a charging adapter, or perform inter-device communication other than wireless power transmission.

[0007] Japanese Patent Publication No. 2017-85855 Japanese Patent Publication No. 2018-153043

[0008] One aspect of this disclosure, in view of the above, aims to provide a technology for appropriately changing the operating mode in a wireless power transmission device.

[0009] An apparatus according to one aspect of the present disclosure comprises a power transmission means for transmitting power wirelessly, a power reception means for receiving power wirelessly, and a selection means for selecting whether the power transmission means is in a first state in which it is operating or a second state in which the power reception means is operational, wherein the selection means switches from the second state to the first state based on the duration of the second state.

[0010] This is a diagram showing an example configuration of a wireless power transmission system consisting of a power transmitting / receiving device and a power receiving device according to Embodiment 1. This is a diagram showing an example configuration of a wireless power transmission system consisting of a power transmitting / receiving device and a power transmitting device according to Embodiment 1. This is a diagram showing an example configuration of a power transmitting / receiving device according to Embodiment 1. This is a diagram showing an example configuration of a power receiving device according to Embodiment 1. This is a diagram showing an example configuration of a power transmitting device according to Embodiment 1. This is a flowchart showing a first example of the processing operation of a power transmitting / receiving device according to Embodiment 1. This is a flowchart showing a first example of the power transmission mode processing in the first example of the processing operation of a power transmitting / receiving device according to Embodiment 1. This is a flowchart showing an example of the power receiving mode processing in the first example of the processing operation of a power transmitting / receiving device according to Embodiment 1. This is a sequence diagram showing an example of processing when a power receiving device is placed on a power transmitting / receiving device according to Embodiment 1. This is a sequence diagram showing an example of processing when nothing is placed on a power transmitting / receiving device according to Embodiment 1. This is a sequence diagram showing an example of processing when an incompatible power receiving device is placed on a power transmitting / receiving device according to Embodiment 1. This is a sequence diagram showing an example of processing when a power transmitting device is placed on a power transmitting / receiving device according to Embodiment 1. This is a flowchart showing a second example of the power transmission mode processing in the first example of the operation processing of the power transmission and receiving device according to Embodiment 2. This is a sequence diagram showing an example of processing when a power transmission device is mounted on the power transmission and receiving device according to Embodiment 2.

[0011] Hereinafter, embodiments of this disclosure will be described in detail with reference to the attached drawings. In the embodiments, as an example of a wireless power transmission system, wireless power transmission based on the Qi standard will be described.

[0012] The following describes cases in which a power transmission / receiving device transmits power to another power receiving device via wireless power transmission, and cases in which a power transmission / receiving device receives power from another power transmission device via wireless power transmission. However, the following embodiments are merely examples to illustrate the technical concept of this disclosure, and this disclosure is not intended to be limited to the configurations and methods described in the embodiments.

[0013] Furthermore, while the embodiments describe multiple features, not all of these features are necessarily essential to this disclosure, and the features may be combined in any way. In addition, in the attached drawings, the same reference numeral is used for identical or similar configurations, and redundant descriptions are omitted.

[0014] <Embodiment 1> [System Configuration] The configuration of the system according to this embodiment will be described with reference to Figures 1A and 1B.

[0015] Figures 1A and 1B show examples of the configuration of a wireless power transmission system according to this embodiment.

[0016] As shown in Figures 1A and 1B, the wireless power transmission system comprises a power transmission / receiving device 100 and a power receiving device 200 or a power transmission device 300. As will be described later, the wireless power transmission system may also consist of only the power transmission / receiving device 100, or it may consist of the power transmission / receiving device 100 and a power receiving device that is not compatible with the power transmission / receiving device 100.

[0017] The power transmission and reception device 100 is an electronic device that wirelessly transmits power to a power receiving device 200 mounted on the power transmission and reception device 100 via an antenna, for example, as shown in Figure 1A. The power transmission and reception device 100 is also an electronic device that is mounted on a power transmission device 300, as shown in Figure 1B, and can receive power wirelessly transmitted from the power transmission device 300 via an antenna.

[0018] In the following explanation, we will use as examples the case where the power receiving device 200 is mounted on the power transmitting and receiving device 100, and the case where the power transmitting and receiving device 100 is mounted on the power transmitting device 300. However, for the power transmitting and receiving device 100 to transmit power to the power receiving device 200, the power receiving device 200 only needs to be within the power transmission range of the power transmitting and receiving device 100 (the range shown by the dashed line in Figure 1A), and does not need to be mounted on the power transmitting and receiving device 100. Similarly, for the power transmitting device 300 to transmit power to the power transmitting and receiving device 100, the power transmitting and receiving device 100 only needs to be within the power transmission range of the power transmitting device 300 (the range shown by the dashed line in Figure 1B), and does not need to be mounted on the power transmitting device 300.

[0019] The power receiving device 200 is an electronic device that receives power wirelessly from, for example, the power transmitting and receiving device 100 and charges its built-in battery.

[0020] The power transmission device 300 is an electronic device that, for example, wirelessly transmits power to the power transmission / receiving device 100 to charge the built-in battery of the power transmission / receiving device 100.

[0021] Each of the power transmission / receiving device 100, power receiving device 200, and power transmission device 300 can be configured as a standalone device or as an integrated device within another device. This other device may include an imaging device, smartphone, smartwatch, tablet PC, laptop PC, portable charger, charger, automobile, robot, medical equipment, printer, etc., and can supply power from or to various other devices.

[0022] [Device Configuration] Next, the configuration of the device according to this embodiment will be described with reference to Figures 2, 3, and 4.

[0023] Figure 2 shows an example of the configuration of the power transmission and reception device 100.

[0024] The power transmission and reception device 100 includes a control unit 101, a power supply unit 102, a power transmission unit 103, a communication unit 104, an antenna (coil) 105, a memory 106, a measurement unit 107, a detection unit 108, a power receiving unit 109, a charging unit 110, and a power transmission / reception switching unit 111. In Figure 2, the control unit 101, power supply unit 102, power transmission unit 103, communication unit 104, memory 106, measurement unit 107, detection unit 108, power receiving unit 109, a charging unit 110, and a power transmission / reception switching unit 111 are shown as separate components. However, any multiple blocks of these may be implemented as the same hardware module (for example, on the same chip).

[0025] The control unit 101 controls the entire power transmission and reception device 100 by executing a control program stored in, for example, memory 106. The control unit 101 controls the power transmission unit 103 and the power reception unit 109, which are compatible with the Qi standard described later. The control unit 101 controls the charging unit 110 to charge the battery (not shown) of the power supply unit 102. The control unit 101 controls the power transmission / reception switching unit 111 to switch the antenna 105 between a state in which the power transmission unit 103 is operational (or is operational) and a state in which the power reception unit 109 is operational (or is operational). The control unit 101 also performs control related to power reception control and power transmission control, including communication for equipment authentication in the power transmission and reception device 100. Furthermore, the control unit 101 may perform control for executing applications other than wireless power transmission. The control unit 101 is configured to include one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 101 may also be configured with hardware dedicated to specific processing, such as an Application Specific Integrated Circuit (ASIC). Furthermore, the control unit 101 may be configured to include an array circuit of an FPGA (Field Programmable Gate Array) compiled to execute specific processing. The control unit 101 stores information that should be stored during the execution of various processes in the memory 106. If the power transmission / reception device 100 is in a state where it can receive power wirelessly transmitted from the power transmission device 300 via an antenna, the control unit 101 may be configured to start up using the received power.

[0026] The power supply unit 102 supplies power to each block. The power supply unit 102 is, for example, a commercial power source or a battery. The battery stores power supplied from the commercial power source or power supplied from the power transmission device 300.

[0027] The power transmission unit 103 converts the DC or AC power input from the power supply unit 102 into AC frequency power in the frequency band used for wireless power transmission, and inputs this AC frequency power to the antenna 105 to generate electromagnetic waves for the power receiving device 200 to receive power. For example, the power transmission unit 103 converts the DC voltage supplied by the power supply unit 102 into an AC voltage using a switching circuit in a half-bridge or full-bridge configuration with an FET (Field Effect Transmitter). In this case, the power transmission unit 103 includes a gate driver that controls the ON / OFF state of the FET. The power transmission unit 103 controls the intensity of the output electromagnetic waves by adjusting the voltage (transmission voltage) or current (transmission current), or both, input to the antenna 105. Increasing the transmission voltage or transmission current increases the intensity of the electromagnetic waves, and decreasing the transmission voltage or transmission current decreases the intensity of the electromagnetic waves. Furthermore, the power transmission unit 103 controls the output of AC frequency power so that power transmission from the antenna 105 is started or stopped based on instructions from the control unit 101. The power transmission unit 103 is also capable of supplying enough power to output 15 watts to the charging unit 205 (shown in Figure 3) of the Qi-compliant power receiving device 200. The power transmission unit 103 can transmit power wirelessly to power receiving devices such as the power receiving device 200.

[0028] The communication unit 104 communicates with the power receiving device 200 for power transmission control based on the Qi standard. The communication unit 104 modulates the electromagnetic waves output from the antenna 105 and transmits information to the power receiving device 200. The communication unit 104 also demodulates the electromagnetic waves output from the antenna 105 and modulated by the power receiving device 200 to obtain the information transmitted by the power receiving device 200. In other words, the communication performed by the communication unit 104 is carried out by superimposing a signal on the electromagnetic waves transmitted from the antenna 105. Alternatively, the communication unit 104 communicates with, for example, the power transmitting device 300 for power receiving control based on the Qi standard. In that case, the communication unit 104 demodulates the electromagnetic waves modulated by the power transmitting device 300 that are input to the antenna 105 to obtain the information received from the power transmitting device 300. In other words, the communication performed by the communication unit 104 is carried out by superimposing a signal on the electromagnetic waves received by the antenna 105. Furthermore, the communication unit 104 may communicate with the power receiving device 200 or the power transmitting device 300 using a communication method that uses a different antenna (not shown) and frequency than the antenna 105. Alternatively, the communication unit 104 may selectively use a different antenna (not shown) than the antenna 105 to communicate with the power receiving device 200 or the power transmitting device 300.

[0029] In addition to storing the control program, memory 106 also stores the status of the power transmission / reception unit 100, the power receiving unit 200, and the power transmission unit 300. Furthermore, memory 106 stores the measured and counted values ​​of time measured by the measurement unit 107. Memory 106 also stores predetermined values ​​related to various parameters of the wireless power transmission system.

[0030] The measuring unit 107 measures time. Furthermore, the measuring unit 107 includes a counter, for example, composed of a combination of flip-flops and logic gates, and counts the time.

[0031] The detection unit 108 detects the status of the power transmission / receiving device 100, the power receiving device 200, and the power transmission device 300. Specifically, the detection unit 108 detects the voltage across the antenna 105. The detection unit 108 also compares the measured time values ​​and count values ​​measured by the measurement unit 107, which are stored in the memory 106, with a predetermined value, and detects whether the measured time values ​​and count values ​​are greater than or less than the predetermined value. The detection unit 108 can also detect the remaining power of the battery (not shown) of the power supply unit 102. The detection unit 108 then compares the detected remaining power with a predetermined value stored in the memory 106, and detects whether the remaining power is greater than or less than the predetermined value.

[0032] Furthermore, the detection unit 108 detects whether the power transmission / reception device 100 is being used or not. The detection unit 108 may, for example, communicate with a motion sensor (not shown) of the power transmission / reception device 100 to detect whether the orientation of the power transmission / reception device 100 has changed or not based on motion data generated by the motion sensor. The detection unit 108 may also, for example, communicate with a camera application running on the power transmission / reception device 100 to detect whether the camera function is operating or not. The detection unit 108 may also, for example, communicate with a display control unit (not shown) of the power transmission / reception device 100 to detect whether a screen is displayed or not on the display (not shown) of the power transmission / reception device 100. The detection unit 108 may also, for example, communicate with a lock control unit (not shown) of the power transmission / reception device 100 to detect whether the power transmission / reception device 100 is unlocked or locked. Furthermore, the detection unit 108 may, for example, communicate with the power supply unit 102 to detect whether the battery level of the power transmission / reception device 100 is decreasing quickly or slowly. Also, the detection unit 108 may, for example, communicate with a temperature sensor (not shown) of the power transmission / reception device 100 to detect whether the temperature of the power transmission / reception device 100 is high or low.

[0033] Furthermore, the detection unit 108, for example, by communicating with the power supply unit 102, detects whether the power transmission / reception device 100 (specifically the battery of the power supply unit 102) is being charged via wire or not.

[0034] The power receiving unit 109 acquires AC power (AC voltage and AC current) generated by electromagnetic induction caused by electromagnetic waves radiated from the power transmitting device 300 at the antenna 105. The power receiving unit 109 then converts the AC power into DC power or AC power of a predetermined frequency and outputs power to the charging unit 110, which performs processing to charge the battery (not shown) of the power supply unit 102. In other words, the power receiving unit 109 supplies power to the load in the power transmitting and receiving device 100. The power receiving unit 109 is assumed to have the capacity to supply enough power to the charging unit 110 to charge the battery (not shown) of the power supply unit 102 and to output 15 watts of power to the charging unit 110. The power receiving unit 109 can receive power wirelessly from a power transmitting device such as the power transmitting device 300.

[0035] The power transmission / reception switching unit 111 switches between connecting the power transmission unit 103 to the antenna 105 or connecting the power reception unit 109 to the antenna 105. In other words, the power transmission / reception switching unit 111 (selectively, for example) switches between a state in which the power transmission unit 103 is operational (or is operational) and a state in which the power reception unit 109 is operational (or is operational). For example, as will be described later, the power transmission / reception switching unit 111 switches from a state in which the power reception unit 109 is operational (or is operational) to a state in which the power transmission unit 103 is operational (or is operational) based on the duration of time the power reception unit 109 remains operational. Although it has been stated that the power transmission / reception switching unit 111 switches the connection, the same function may be achieved by the control unit 101 controlling whether to operate the power transmission unit 103 or the power reception unit 109. As will be explained below, the state in which the antenna 105 is connected to the power transmission unit 103 (the state in which the power transmission unit 103 is operational (or is operational)) is called the power transmission mode. Also, the state in which the antenna 105 is connected to the power receiving unit 109 (the state in which the power receiving unit 109 is operational (or is operational)) is called the power receiving mode. The power transmission / reception switching unit 111 may choose not to connect either the power transmission unit 103 or the power receiving unit 109 to the antenna 105. In other words, the power transmission / reception switching unit 111 does not necessarily have to select either the power transmission mode or the power receiving mode, and may select any other mode. Furthermore, in the following, the power receiving mode means the state in which the power receiving unit 109 is connected to the antenna 105, and the expressions "the power receiving unit 109 is operational" and "operating in power receiving mode" mean that the power receiving unit 109 is in an operational state. Here, the state in which the power receiving unit 109 is operational means that the power receiving unit 109 is waiting for power, and does not necessarily mean that the power receiving unit 109 is performing any operation. Furthermore, in the following, the time for which the power receiving unit 109 operates continuously and the time for which it operates continuously in power receiving mode mean the time for which the power receiving unit 109 remains in an operational state.

[0036] When the antenna 105 is connected to the power receiving unit 109 by the power transmission / reception switching unit 111, it generates AC power (AC voltage and AC current) through electromagnetic induction caused by electromagnetic waves radiated from the power transmission device 300. Also, when the antenna 105 is connected to the power transmission unit 103 by the power transmission / reception switching unit 111, it generates electromagnetic waves from the power transmission / reception device 100 by receiving AC power (AC voltage and AC current) from the power transmission unit 103.

[0037] Figure 3 shows an example of the configuration of the power receiving device 200.

[0038] The power receiving device 200 includes a control unit 201, a power receiving unit 202, a communication unit 203, a power receiving antenna (power receiving coil) 204, a charging unit 205, a battery 206, and a memory 207. In Figure 3, the control unit 201, power receiving unit 202, communication unit 203, charging unit 205, battery 206, and memory 207 are shown as separate components. However, any multiple of these blocks may be implemented as the same hardware module (for example, on the same chip).

[0039] The control unit 201 controls the entire power receiving device 200 by executing a control program stored in, for example, the memory 207. That is, the control unit 201 controls each of the functional units shown in Figure 3. Furthermore, the control unit 201 may also perform control for executing applications other than wireless power transmission. An example of the control unit 201 is configured to include one or more processors such as a CPU or MPU. The control unit 201 may also control the entire power receiving device 200 in cooperation with the OS (Operating System) that the control unit 201 is running. The control unit 201 may also be configured with hardware dedicated to specific processing, such as an ASIC. Furthermore, the control unit 201 may be configured to include an FPGA array circuit compiled to execute predetermined processing. The control unit 201 stores information that should be stored while various processing is being executed in the memory 207.

[0040] The power receiving unit 202 obtains alternating current power (alternating current voltage and alternating current) generated by electromagnetic induction caused by the electromagnetic wave radiated from the antenna 105 of the power transmission and reception device 100 in the power receiving antenna 204. Then, the power receiving unit 202 converts the alternating current power into direct current or alternating current power of a predetermined frequency, and outputs the power to a charging unit 205 that performs a process of charging the battery 206. That is, the power receiving unit 202 supplies power to the load in the power receiving device 200. It is assumed that the power receiving unit 202 has the ability to supply power for the charging unit 205 to charge the battery 206 and supply only the power capable of outputting 15 watts of power to the charging unit 205.

[0041] The communication unit 203 communicates with the communication unit 104 of the power transmission and reception device 100 for power reception control based on the Qi standard as described above. The communication unit 203 demodulates the electromagnetic wave input from the power receiving antenna 204 to obtain the information transmitted from the power transmission and reception device 100. Then, the communication unit 203 superimposes a signal related to the information to be transmitted to the power transmission and reception device 100 on the electromagnetic wave by load-modulating the input electromagnetic wave, thereby communicating with the power transmission and reception device 100. Further, the communication unit 203 may communicate with the power transmission and reception device 100 using communication using an antenna (not shown) different from the power receiving antenna 204 and a frequency, or may communicate with the power transmission and reception device 100 by selectively using an antenna (not shown) different from the power receiving antenna 204.

[0042] In addition to storing the control program, the memory 207 also stores the states of the power transmission and reception device 100 and the power receiving device 200 and the like.

[0043] FIG. 4 is a diagram showing a configuration example of the power transmission device 300.

[0044] The power transmission device 300 includes a control unit 301, a power supply unit 302, a power transmission unit 303, a communication unit 304, a power transmission antenna (power transmission coil) 305, and a memory 306. In FIG. 4, the control unit 301, the power supply unit 302, the power transmission unit 303, the communication unit 304, and the memory 306 are described as separate bodies. However, any plurality of these blocks may be implemented as the same hardware module (for example, within the same chip).

[0045] The control unit 301 controls the entire power transmission device 300 by executing a control program stored in, for example, the memory 306. The control unit 301 controls the power transmission unit 303 which is compliant with the Qi standard, as described later. The control unit 301 also performs control related to power transmission control, including communication for equipment authentication in the power transmission device 300. Furthermore, the control unit 301 may perform control for executing applications other than wireless power transmission. The control unit 301 is configured to include, for example, one or more processors such as a CPU or MPU. The control unit 301 may also be configured with hardware dedicated to a specific process, such as an ASIC. The control unit 301 may also be configured to include an FPGA array circuit compiled to execute a specific process. The control unit 301 stores information that should be stored while various processes are being executed in the memory 306.

[0046] The power supply unit 302 supplies power to each block. The power supply unit 302 is, for example, a commercial power source or a battery. Power supplied from the commercial power source is stored in the battery.

[0047] The power transmission unit 303 converts the DC or AC power input from the power supply unit 302 into AC frequency power in the frequency band used for wireless power transmission, and inputs this AC frequency power to the power transmission antenna 305 to generate electromagnetic waves for power transmission and reception device 100 to receive. For example, the power transmission unit 303 converts the DC voltage supplied by the power supply unit 302 into an AC voltage using a switching circuit with a half-bridge or full-bridge configuration using an FET. In this case, the power transmission unit 303 includes a gate driver that controls the ON / OFF state of the FET. The power transmission unit 303 controls the intensity of the output electromagnetic waves by adjusting the voltage (transmission voltage) or current (transmission current), or both, input to the power transmission antenna 305. The power transmission unit 303 also controls the output of the AC frequency power so that power transmission from the power transmission antenna 305 is started or stopped based on instructions from the control unit 301. Furthermore, the power transmission unit 303 is assumed to have the capacity to supply enough power to output 15 watts of power to the charging unit 110 of the Qi-compliant power transmission and reception device 100.

[0048] The communication unit 304 communicates with the power transmission and reception device 100 for power transmission control based on the Qi standard. The communication unit 304 modulates the electromagnetic wave output from the power transmission antenna 305 and transmits information to the power transmission and reception device 100. Further, the communication unit 304 demodulates the electromagnetic wave that is output from the power transmission antenna 305 and modulated by the power transmission and reception device 100, and acquires the information transmitted by the power transmission and reception device 100. That is, the communication performed by the communication unit 304 is performed by superimposing a signal on the electromagnetic wave transmitted from the power transmission antenna 305.

[0049] In addition to storing the control program, the memory 306 also stores the states of the power transmission device 300 and the power transmission and reception device 100, etc.

[0050] [Processing Operations of Power Transmission and Reception Device] Next, the processing operations of the power transmission and reception device 100 will be described using FIG. 5.

[0051] FIG. 5 is a flowchart showing a first example of the processing operations of the power transmission and reception device 100. The processing shown in FIG. 5 is continuously and repeatedly executed while the power transmission and reception device 100 is activated.

[0052] It is assumed that the power transmission and reception device 100 is operating in the power reception mode (S401). The power reception mode here refers to a state in which electric power can be extracted from a power signal from another wireless power supply device (A subsystem that can extract electric power from a Power Signal.). More specifically, the power reception mode is a state in which the power transmission / reception switching unit 111 of the power transmission and reception device 100 connects the power reception unit 109 to the antenna 105 and does not connect the power transmission unit 103 to the antenna 105.

[0053] The power transmission / reception device 100 measures the time it is operating in power reception mode using the measurement unit 107. If time measurement is not being performed (N in S402), time measurement is started (S403). If the power transmission / reception device 100 is measuring the time it is operating in power reception mode (Y in S402), or if time measurement has been started, it determines whether the time it has been continuously operating in power reception mode (the time the power receiving unit 109 is continuously operating) has reached a predetermined time (S404). This determination is made by the detection unit 108. If the time it has been continuously operating in power reception mode has not reached the predetermined time (N in S404), the power transmission / reception device 100 remains in power reception mode (S405) and performs power reception mode processing (S406). Details of power reception mode processing will be explained separately. If the time it has been continuously operating in power reception mode has reached the predetermined time (Y in S404), the power transmission / reception device 100 switches from power reception mode to power transmission mode (S407). Then, the power transmission / reception device 100 performs power transmission mode processing (S408). Details of the power transmission mode processing will be explained separately.

[0054] The predetermined time referred to here is, for example, 500 milliseconds, which is defined in the Qi standard as the interval for object detection by Analog Ping. By setting the predetermined time to be the same as the interval for object detection by Analog Ping, the power transmission / reception device 100 can receive at least one Analog Ping within the predetermined time. However, the predetermined time is not limited to the time defined as the interval for object detection (500 milliseconds).

[0055] Here, Analog Ping is a short-duration power signal (electromagnetic wave) output from a coil (antenna 105 or transmitting antenna 305) by a power-transmitting device (power-transmitting / receiving device 100 or power-transmitting device 300) to detect the presence of an object. The power-transmitting device determines the presence or absence of an object by transmitting a short pulse of, for example, about 70 microseconds. By outputting Analog Ping and measuring the antenna voltage in response, for example, the power-transmitting / receiving device 100 can detect that a power-receiving device 200 or a conductive piece has been placed on it. However, even if the detected object is, for example, the power-receiving device 200, the control unit 201 of the power-receiving device 200 will not be activated by Analog Ping.

[0056] Next, if the power transmission mode is terminated (Y in S409), the power transmission / reception device 100 resets the measurement of the continuous operation time in power reception mode (S410). Specifically, the power transmission / reception device 100 erases the time measurement value stored in memory 106. After that, the power transmission / reception device 100 switches from power transmission mode to power reception mode (S411). If the power transmission mode is not terminated (N in S409), the power transmission / reception device 100 repeats the power transmission mode processing.

[0057] As described above, when the power transmission / reception device 100 has been operating continuously in power reception mode for a predetermined period of time (Y in S404), the power transmission / reception device 100 switches from power reception mode to power transmission mode. Then, when the power transmission mode ends (Y in S409), the power transmission / reception device 100 switches from power transmission mode to power reception mode. The power transmission / reception device 100 can automatically switch from power reception mode to power transmission mode or from power transmission mode to power reception mode without requiring user operation.

[0058] [Power transmission mode processing of the power transmission and receiving device] Next, the power transmission mode processing of the power transmission and receiving device 100 (S408 in Figure 5) will be explained using Figure 6.

[0059] Figure 6 is a flowchart showing a first example of the power transmission mode processing in a first example of the processing operation of the power transmission and receiving device 100.

[0060] The power transmission mode referred to here is a state in which a power signal is generated by the control unit 101 and electromagnetic waves can be output from the antenna 105 (A subsystem that can generate a power signal). More specifically, it is a state in which the power transmission / reception switching unit 111 of the power transmission / reception device 100 has the power transmission unit 103 connected to the antenna 105, but the power reception unit 109 is not connected to the antenna 105.

[0061] The control unit 101 of the power transmission / reception device 100 transitions to the Selection Phase (S412). Then, the power transmission / reception device 100 transmits Analog Ping via the power transmission unit 103 and the antenna 105 (S413).

[0062] The power transmission / reception device 100 performs object detection by detecting at least one of the voltage value and current value of the antenna 105 when an Analog Ping is transmitted using the detection unit 108 (S414). The power transmission / reception device 100 determines that there are no objects around the antenna 105 if the voltage exceeds a certain threshold or the current value does not exceed a certain threshold (N in S414). In that case, the power transmission / reception device 100 counts the number of times it has determined that there are no objects around the antenna 105 using the measurement unit 107 (S415), and stores the counted number in the memory 106.

[0063] The power transmission and reception device 100 uses a detection unit 108 to detect whether the count value stored in the memory 106 is above a predetermined value or below a predetermined value (S416).

[0064] If the count value is less than a predetermined value (N in S416), the power transmission / reception device 100 returns to Selection Phase and transmits Analog Ping again (S413). If the count value is greater than or equal to a predetermined value (Y in S416), the power transmission / reception device 100 erases the count value stored in memory 106 (S417), stops power transmission (S427), and terminates the power transmission mode processing. The predetermined value here is, for example, one or two times, but is not limited to that. The predetermined value may be set to two times in order to check the change in the Q value (Quality Factor) by transmitting Analog Ping. Also, the predetermined value may be set to two or more times in order to statistically analyze the Q value. If the change in the Q value is not to be checked or the Q value is not to be statistically analyzed, the predetermined value may be set to one time.

[0065] Note that when it is determined that no object exists (N in S414), it means that there is no object in the transmission area of ​​the Analog Ping of the power transmission / reception device 100. To reiterate, in this case, the voltage value for Analog Ping does not fall below a certain threshold, or the current value does not exceed a certain threshold, and the power transmission / reception device 100 determines that no object exists. By terminating the power transmission mode processing when the number of times it is determined that no object exists during Analog Ping transmission exceeds a predetermined value, unnecessary Analog Ping transmissions can be suppressed, thereby achieving power saving. Note that the threshold referred to here is the voltage value or current value of the antenna 105 when Analog Ping is transmitted when no object is present around the antenna 105. In other words, the threshold referred to here is the voltage or current value of the antenna 105 when transmitting an Analog Ping, provided that there are no objects within the region that causes a change in the voltage and current values ​​of the antenna 105 when transmitting the Analog Ping.

[0066] In this embodiment, the determination of the end of the power transmission mode processing was explained using the number of times it was determined that no object exists based on Analog Ping transmission as an example, but other configurations are also possible. Specifically, the power transmission / reception device 100 may, for example, terminate the power transmission mode processing if it determines that no object exists within a predetermined time after transmitting Analog Ping. The predetermined time here is, for example, the sum of the 500 millisecond interval for object detection by Analog Ping as defined in the Qi standard and the 70 microsecond period for object detection by Analog Ping. By setting the predetermined time to the sum of the interval for object detection by Analog Ping and the period for object detection by Analog Ping, object detection by Analog Ping can be performed at least once within the predetermined time. If Analog Ping determines that no object exists within a predetermined time, the power transmission mode processing is terminated, thereby suppressing the transmission of unnecessary Analog Pings and thus achieving power savings.

[0067] The power transmission / reception device 100 determines that an object is present around the antenna 105 if the voltage value of the antenna 105 falls below a certain threshold or the current value exceeds a certain threshold when an Analog Ping is transmitted (Y in S414). The power transmission / reception device 100 then switches to the Ping Phase (S418).

[0068] Assume that the object detected by the power transmission / reception device 100 via Analog Ping transmission is the power receiving device 200. In the Ping Phase, the power transmission / reception device 100 transmits a Digital Ping (S419). The Digital Ping is a power signal for activating the control unit 201 of the power receiving device 200, and transmits a larger amount of power continuously than the Analog Ping. The power transmission / reception device 100 uses the Digital Ping to activate the control unit 201 of the power receiving device 200.

[0069] Next, if the power transmission / receiving device 100 is N in S420 and Y in S421, it proceeds to the Configuration Phase (S422). That is, if the power transmission / receiving device 100 does not receive an End Power Transfer Packet from the power receiving device 200 but receives a Signal Strength Packet, it proceeds to the Configuration Phase (S422). Note that the End Power Transfer Packet is labeled as EPTP in Figure 6, and the Signal Strength Packet is a response to the power receiving voltage notification that notifies the magnitude of the power receiving voltage, and is labeled as SSP in Figure 6. The power transmission and reception device 100 can recognize that an object placed in the area indicated by the dashed line in Figure 1A is a device capable of charging according to the Qi standard by receiving a Signal Strength Packet via the communication unit 104.

[0070] When the power transmission / receiving device 100 receives an End Power Transfer Packet in the Ping Phase (Y in S420), it stops transmitting power (S427) and terminates the power transmission mode processing. By terminating the power transmission mode upon receiving the End Power Transfer Packet, it is possible to avoid supplying power to the fully charged battery 206 of the power receiving device 200. This enables power saving and prevents overcharging of the battery of the power receiving device 200.

[0071] On the other hand, if the power transmission / receiving device 100 is N in S420 and N in S421, it cannot proceed to the Configuration Phase. In other words, if the power transmission / receiving device 100 does not receive the End Power Transfer Packet in the Ping Phase and cannot receive the Signal Strength Packet, it cannot proceed to the Configuration Phase. The case in which the Signal Strength Packet cannot be received from the power receiving device 200 is when an object close to the power transmission / receiving device 100 is detected by Analog Ping, but the detected object is, for example, the following device. In other words, this occurs when the detected object is a power receiving device that is not compatible with the power transmitting / receiving device 100, or a power transmitting device, or a power transmitting / receiving device that is operating in power transmission mode. In this case, the power transmitting / receiving device 100 cannot obtain a response to Digital Ping.

[0072] If the power transmission / reception device 100 cannot receive a Signal Strength Packet from the power reception device 200 (N in S421), it performs the following operation: The power transmission / reception device 100 counts the number of times it has failed to receive a Signal Strength Packet using the measurement unit 107 (S415), and stores the counted number in the memory 106.

[0073] The power transmission and reception device 100 uses a detection unit 108 to detect whether the count value stored in the memory 106 is greater than or equal to a predetermined value or less than a predetermined value (S416).

[0074] If the count value is less than a predetermined value (N in S416), the power transmission / receiving device 100 returns to Selection Phase and transmits Analog Ping again (S413). If the count value is greater than or equal to a predetermined value (Y in S416), the power transmission / receiving device 100 erases the count value stored in memory 106 (S417), stops power transmission (S427), and terminates the power transmission mode processing. If the number of times the power transmission / receiving device 100 fails to receive a Signal Strength Packet from the power receiving device 200 in response to a Digital Ping transmission reaches a predetermined value, the power transmission mode processing is terminated. This suppresses the transmission of unnecessary Digital Pings, thereby achieving power savings. Furthermore, when the power transmission / receiving device 100 is placed on the power transmission device 300, it is possible to avoid the power transmission / receiving device 100 continuously transmitting Digital Ping to the power transmission device 300 and unintentionally causing adverse effects.

[0075] In this embodiment, the counting of the number of times Analog Ping determines that no object exists and the number of times it determines that it cannot receive a Signal Strength Packet from the power receiving device 200 are described as a common flow, but this is not limited to this. The transmitting and receiving device 100 may count each number independently and decide whether to retransmit Analog Ping or stop power transmission. When each number is counted independently, the predetermined value for the number of times the Signal Strength Packet cannot be received from the power receiving device 200 in response to Digital Ping transmission is, for example, 1, but is not limited to this.

[0076] In this embodiment, the termination of the power transmission mode processing was explained using the number of times a Signal Strength Packet is not received in response to a Digital Ping as an example, but other configurations are also possible. Specifically, the power transmission / receiving device 100 may terminate the power transmission mode processing if, for example, it does not receive a Signal Strength Packet within a predetermined time after transmitting a Digital Ping. The predetermined time here is, for example, 70 milliseconds as defined in the Digital Ping Window of the Qi standard. By terminating the power transmission mode processing when the power transmission / receiving device 100 does not receive a Signal Strength Packet from the power receiving device 200 within a predetermined time, unnecessary transmission of Digital Pings can be suppressed, thereby achieving power saving. Furthermore, when the power transmission / receiving device 100 is placed on the power transmission device 300, it is possible to avoid the power transmission / receiving device 100 continuously transmitting Digital Ping to the power transmission device 300 and unintentionally causing adverse effects.

[0077] In the Configuration Phase, the power transmission / receiving device 100 identifies the power receiving device 200 and obtains equipment configuration information from the power receiving device 200. Specifically, the power transmission / receiving device 100 receives an Identification Packet containing identifier information (or identification information) transmitted from the power receiving device 200. Subsequently, the power transmission / receiving device 100 receives a Configuration Packet containing equipment configuration information transmitted from the power receiving device 200. The power transmission / receiving device 100 refers to this Packet and proceeds to the Negotiation Phase (S423).

[0078] In the Negotiation Phase, the power transmission / receiving device 100 negotiates with the power receiving device 200 to determine the Guaranteed Load Power. The Guaranteed Load Power here refers to the guaranteed load power, which is the load power level agreed upon between the power transmission / receiving device 100 and the power receiving device 200. This load power level is defined as "A Load Power level agreed between the Power Receiver and the Power Transmitter." When the power transmission / receiving device 100 receives a Specific Request Packet from the power receiving device 200 requesting the termination of the Negotiation Phase, it transitions to the Power Transfer Phase (S424).

[0079] In the Power Transfer Phase, the power transmission / reception device 100 first determines the parameters necessary for the foreign object detection function. The foreign object detection function is a function in which the power transmission / reception device 100 detects, for example, the presence of an object other than the power reception device 200 near the receiving antenna 204, or the presence of an object other than the power reception device 200 between the antenna 105 and the receiving antenna 204. The power transmission / reception device 100 adjusts the power transmission output so that the power reception device 200 can be charged with the authorized Guaranteed Load Power value or the responded Guaranteed Load Power. After that, the power transmission / reception device 100 supplies power to the charging section 205 of the power reception device 200.

[0080] The power transmission and receiving device 100 continues the power transmission process until it receives an End Power Transfer Packet from the power receiving device 200 (S425).

[0081] When the power transmission / reception device 100 receives an End Power Transfer Packet (Y in S426), it stops power transmission (S427) and terminates the power transmission mode processing. Depending on the version of the Qi standard, the above-mentioned foreign object detection may be treated separately from the Power Transfer Phase as a Calibration Phase.

[0082] [Determination of termination of power transmission mode] The determination of termination of power transmission mode (S409) is made, for example, as follows: The power transmission and receiving device 100 terminates the power transmission mode when the power transmission and receiving device 100 stops transmitting power during the power transmission mode processing (S427). Alternatively, the power transmission and receiving device 100 may terminate the power transmission mode when the power transmission and receiving device 100 receives the End Power Transfer Packet for the power transmission mode processing (Y in S420 or Y in S426). This prevents the power transmission and receiving device 100 from terminating the power transmission mode processing while transmitting power.

[0083] As an alternative, for example, the power transmission / receiving device 100 may enter transmission mode (S407), and then a step may be added in which the voltage across the antenna 105 is checked before the power transmission device 100 starts transmitting power, and a decision is made to terminate the transmission mode. This allows the power transmission / receiving device 100 to detect power transmission from the power transmission device 300 even when it is placed on the power transmission device 300 while operating in transmission mode. Specifically, the power transmission / receiving device 100 terminates the transmission mode if, for example, the voltage across the antenna 105 of the power transmission / receiving device 100 before it starts transmitting power is above a predetermined threshold. The case where the voltage is above a predetermined threshold is, for example, the following: the voltage value of the antenna 105 before the power transmission / receiving device 100 transmits Analog Ping is above the voltage value of the antenna 105 before the Analog Ping is transmitted when the power receiving device 200 is placed on the power transmission / receiving device 100. Although this explanation uses the period before sending an Analog Ping as an example, the same judgment can be made between sending an Analog Ping and sending a Digital Ping, for example.

[0084] As another example of the decision-making process, the power transmission / reception device 100 may terminate the power transmission mode if it detects a voltage above a predetermined value as a response to transmitting an Analog Ping. Here, a voltage above a predetermined value refers to, for example, a voltage value greater than the Analog Ping transmitted by the power transmission / reception device 100.

[0085] Alternatively, as yet another example of the decision-making process, the power transmission / reception device 100 may terminate the power transmission mode if it detects a voltage waveform different from a predetermined waveform as a response to transmitting an Analog Ping. Here, a voltage waveform different from a predetermined waveform is, for example, a waveform that is not the attenuated waveform of the Analog Ping transmitted by the power transmission / reception device 100 (i.e., the predetermined waveform is the attenuated waveform of the Analog Ping transmitted by the power transmission / reception device 100).

[0086] In these cases, terminating the power transmission mode prevents the power transmission / receiving device 100 from performing power transmission mode processing even though it is receiving power from the power transmission device 300.

[0087] As another variation, a determination process for terminating the power transmission mode process may be added inside the power transmission mode process S408, etc., depending on the remaining power (battery level) of the battery (not shown) of the power supply unit 102. The power transmission / receiving device 100 may, for example, terminate the power transmission mode when the remaining power falls below a predetermined threshold. Alternatively, the power transmission / receiving device 100 may terminate the power transmission mode when the remaining power of the battery of the power supply unit 102 of the power transmission / receiving device 100 is below a predetermined threshold and the power transmission / receiving device 100 is not being charged via wire. The predetermined threshold here is, for example, 50% of the battery capacity. In this way, if the remaining power of the battery of the power transmission / receiving device 100 is low, it switches from power transmission mode to power reception mode, so that the battery of the power transmission / receiving device 100 does not become completely empty. Alternatively, the power transmission / receiving device 100 may simply terminate the power transmission mode when the power transmission / receiving device 100 is not being charged via wire. As a result, the power transmission / reception unit 100 does not enter power transmission mode when it is not being charged via wire, thus preventing the battery charge in the power supply unit 102 of the power transmission / reception unit 100 from decreasing rapidly.

[0088] As another variation, a step to determine whether to terminate the power transmission mode may be added to the power transmission mode processing S408 when the detection unit 108 detects, by any of the means described above, that the power transmission device 100 is in use. The power transmission device 100 is in use in this context means, for example, the following: the orientation of the power transmission device 100 has changed, the camera function is operating, the screen is displayed, it is unlocked, the battery level is decreasing rapidly (for example, above a predetermined value), the temperature is high (for example, above a predetermined value), etc. This avoids a state where power is being transmitted while the power transmission device 100 is in use, thereby suppressing the temperature rise of the power transmission device 100 and preventing it from becoming inoperable due to overheating.

[0089] The above describes the criteria for determining when to terminate the power transmission mode. Conversely, the power transmission / receiving device 100 does not need to terminate the power transmission mode if, for example, the remaining power of the battery in the power supply unit 102 of the power transmission / receiving device 100 is above a predetermined value. Alternatively, the power transmission / receiving device 100 does not need to terminate the power transmission mode if the detection unit 108 detects, by any of the means described above, that the power transmission / receiving device 100 is not in use. The power transmission / receiving device 100 not being in use means, for example, the following: the orientation of the power transmission / receiving device 100 has not changed, the camera function is not operating, the screen is not displayed, it is locked, the battery level is decreasing slowly (for example, below a predetermined value), the temperature is low (for example, below a predetermined value), etc. Furthermore, the power transmission / receiving device 100 does not need to terminate the power transmission mode if it is being charged via a wired connection. These measures make it possible to shorten the time from when the device to be charged is placed on the power transmission / receiving device 100 until charging begins.

[0090] Although several examples of determining the end of the power transmission mode have been shown here, the power transmission and receiving device 100 may determine the end of the power transmission mode using only one example, or it may determine it by arbitrarily combining multiple examples.

[0091] [Power receiving mode processing of the power transmission and receiving device] Next, the power receiving mode processing of the power transmission and receiving device 100 (S406 in Figure 5) will be explained using Figure 7.

[0092] Figure 7 is a flowchart showing an example of the power receiving mode processing in the first example of the processing operation of the power transmission and receiving device 100.

[0093] In the receiving mode, the transmitting and receiving device 100 waits for power transmission from the transmitting device 300. If the transmitting and receiving device 100 is unable to receive the receiving voltage (N in S428), it terminates the receiving mode process. On the other hand, if the transmitting and receiving device 100 receives the receiving voltage (Y in S428), it transitions to the Ping Phase (S429).

[0094] In the Ping Phase, the power transmission / reception device 100 transmits either a Signal Strength Packet or an End Power Transfer Packet (S430). If the power transmission / reception device 100 transmits a Signal Strength Packet (Y in S430), it proceeds to the Configuration Phase (S431). On the other hand, if the power transmission / reception device 100 does not transmit a Signal Strength Packet (N in S430), for example, if the battery of the power transmission / reception device 100 is fully charged and power reception is not required, it performs the following operation. That is, the power transmission / reception device 100 transmits an End Power Transfer Packet and terminates the power reception mode processing.

[0095] In the Configuration Phase, the power transmission / receiving device 100 transmits an Identification Packet containing identifier information. Subsequently, the power transmission / receiving device 100 transmits a Configuration Packet containing equipment configuration information. When the power transmission / receiving device 100 receives an ACK Packet from the power transmission device 300 in response to the Configuration Packet, it proceeds to the Negotiation Phase (S432).

[0096] In the Negotiation Phase, the power transmission / reception device 100 negotiates to determine the Guaranteed Load Power. The power transmission / reception device 100 sends a Specific Request Packet requesting the termination of the Negotiation Phase. If the power transmission / reception device 100 receives an ACK Packet from the power transmission device 300 in response to the Specific Request Packet, it transitions to the Power Transfer Phase (S433).

[0097] In the Power Transfer Phase, the power transmission / reception device 100 first determines the parameters necessary for the foreign object detection function. Then, when power is received by the antenna 105, the power transmission / reception device 100 supplies power to the charging unit 110 (S434).

[0098] When the battery (not shown) of the power supply unit 102 is fully charged (Y in S435), the power transmission / reception device 100 transmits an End Power Transfer Packet (S436). Subsequently, when there is no more power reception at the antenna 105 (Y in S437), the power transmission / reception device 100 terminates the power reception mode processing. On the other hand, if the battery of the power supply unit 102 is not fully charged (N in S435), or if there is power reception at the antenna 105 (N in S437), the power transmission / reception device 100 continues to receive power (S434). Note that depending on the version of the Qi standard, the above-mentioned foreign object detection may be treated separately from the Power Transfer Phase as a Calibration Phase.

[0099] [Decision to switch to power transmission mode (predetermined time)] In this embodiment, the power transmission / receiving device 100 switches to power transmission mode (S407) when the time spent continuously operating in power reception mode reaches a predetermined time (Y in S404). It has been explained that by setting the predetermined time to the same as, for example, the interval for object detection by Analog Ping, the power transmission / receiving device 100 can receive at least one Analog Ping within the predetermined time. However, by setting the predetermined time to the same as the interval for object detection by Analog Ping, it is possible that the power transmission / receiving device 100 may receive an Analog Ping within the predetermined time but not a Digital Ping. The Qi standard specifies that the period during which the power transmission device detects objects using Analog Ping (Object detection duration) is 70 microseconds. Furthermore, when an object is detected using Analog Ping, the power transmission device is required to switch to Ping Phase and transmit a Digital Ping. In other words, a period of 70 microseconds is required between the transmission of an Analog Ping and the transmission / reception device 100 transmitting a Digital Ping. If the predetermined time is set to be the same as the interval for object detection using Analog Ping, for example, if the transmission / reception device 100 receives an Analog Ping with 70 microseconds remaining in the receiving mode, the following will occur: The transmission / reception device 100 will enter transmission mode before receiving the Digital Ping and will not be able to receive the Digital Ping. To avoid this, the predetermined time may be set to be at least longer than the interval for object detection using Analog Ping. Specifically, for example, the predetermined time is set to be 70 microseconds longer than the interval for object detection by Analog Ping compared to the period for object detection by Analog Ping. This allows the power transmission / reception device 100 to perform at least one object detection by Analog Ping and receive a Digital Ping within the predetermined time. Furthermore, the Qi standard specifies that the period from receiving a Digital Ping to the power transmission device responding to the Digital Ping is 70 milliseconds.To enable the power transmission / reception device 100 to respond to the Digital Ping within a predetermined time, the predetermined time may be set as follows: That is, the predetermined time may be the sum of the interval for object detection by Analog Ping as defined in the Qi standard, the period for object detection by Analog Ping, and the period until a response is made to the Digital Ping. This enables the power transmission / reception device 100 to perform at least one object detection by Analog Ping, receive a Digital Ping, and respond to the Digital Ping within the predetermined time.

[0100] Furthermore, the predetermined time is not a constant value but may be varied over time. For example, the predetermined time for the first power receiving mode can be set to 500 milliseconds, the same as the interval for object detection by Analog Ping as defined in the Qi standard. Then, for example, the predetermined time for the next power receiving mode can be set to be 70 microseconds longer than the predetermined time for the first power receiving mode, which is the period for object detection by Analog Ping. Furthermore, the predetermined time for the power receiving mode after that can be set to be 70 microseconds longer than the predetermined time for the next power receiving mode, which is the period for object detection by Analog Ping. In this way, by changing the predetermined time for each power receiving mode, the power transmission / reception device 100 can receive Analog Ping in subsequent power receiving modes even if it cannot receive Analog Ping in the first power receiving mode. This prevents a situation where the power receiving mode cycle of the power transmission / receiving device 100 unintentionally coincides with, for example, the transmission cycle of Analog Ping transmitted from the power transmission device 300, resulting in the power transmission / receiving device 100 being unable to receive Analog Ping. Here, Analog Ping was used as an example, but reception of Digital Ping can also be handled similarly by setting a predetermined time range of variation, taking into account the period until a response is made to Digital Ping.

[0101] Furthermore, the predetermined time may be changed depending on the status of the battery (not shown) of the power transmission / reception device 100, such as the remaining power (battery level). For example, the power transmission / reception device 100 shortens the predetermined time when the remaining power of the battery in the power supply unit 102 of the power transmission / reception device 100 is above a predetermined threshold. The predetermined threshold here is, for example, 50% of the battery capacity. As a result, when the battery level of the power transmission / reception device 100 is high, the period during which the power transmission / reception device 100 operates in power receiving mode is shortened, thus shortening the period from when the power receiving device 200 is placed on the power transmission / reception device 100 until the power transmission / reception device 100 starts charging. Alternatively, if the predetermined threshold is, for example, 90% of the battery capacity, and this is met, the power transmission / reception device 100 may set the predetermined time to 0. In other words, when the battery level is high, the power transmission / reception device 100 may always operate in power transmission mode. This further shortens the time from when the power receiving device 200 is placed on the power transmitting / receiving device 100 until the power transmitting / receiving device 100 begins charging. Alternatively, the power transmitting / receiving device 100 may extend the predetermined time if the remaining power of the battery in the power supply unit 102 of the power transmitting / receiving device 100 is below a predetermined threshold. The predetermined threshold here is, for example, 50% of the battery capacity. This extends the period during which the power transmitting / receiving device 100 operates in power receiving mode when the battery level is low, thus preventing the power transmitting / receiving device 100 from running out of battery power. Furthermore, if the predetermined threshold is, for example, 10% of the battery capacity, and this is met, the power transmitting / receiving device 100 may set the predetermined time to infinity. In other words, when the battery capacity is low, the power transmitting / receiving device 100 may always operate in power receiving mode. This prevents the battery of the power transmitting / receiving device 100 from running out of power. In transmission mode, object detection and digital ping are transmitted using Analog Ping, so the power consumption of the power transmission / reception device 100 is higher when operating in transmission mode than when operating in reception mode. In other words, if the battery level of the power transmission / reception device 100 is low, the period during which the power transmission / reception device 100 operates in reception mode is extended.

[0102] In this specification, "shortening the predetermined time" may mean setting the predetermined time to be shorter than a predetermined time (for example, the time set as the interval for object detection as described above; referred to as the reference time or default time). Alternatively, "shortening the predetermined time" may mean setting the predetermined time to be shorter than the predetermined time (first time) set by "lengthening the predetermined time" (as the second time). Similarly, "lengthening the predetermined time" may mean setting the predetermined time to be longer than the reference time. Alternatively, "lengthening the predetermined time" may mean setting the predetermined time to be longer than the predetermined time (second time) set by "shortening the predetermined time" (as the first time).

[0103] Furthermore, although an example with one predetermined threshold has been described above, in this specification, there may be multiple predetermined thresholds (for example, 10%, 30%, 50%, 70%, and 90% of the battery capacity). In this case, the power transmission / reception device 100 may gradually shorten (or lengthen) the predetermined time according to the range defined by the threshold.

[0104] Furthermore, if the power transmission / receiving device 100 is being charged via a wire, the predetermined time for the power transmission / receiving device 100 may be shortened. This shortens the period during which the power transmission / receiving device 100 operates in power receiving mode when it is being charged via a wire, thereby shortening the time from when the power receiving device 200 is placed on the power transmission / receiving device 100 until the power transmission / receiving device 100 begins charging. Alternatively, if the power transmission / receiving device 100 is not being charged via a wire, the predetermined time for the power transmission / receiving device 100 may be lengthened. This lengthens the period during which the power transmission / receiving device 100 operates in power receiving mode when it is not being charged via a wire, thereby mitigating the depletion of the battery level of the power transmission / receiving device 100.

[0105] Furthermore, if the detection unit 108 detects by any of the above-mentioned means that the power transmission / reception device 100 is not in use, the power transmission / reception device 100 may shorten the predetermined time. Here, "the power transmission / reception device 100 is not in use" means, for example, that the power transmission / reception device 100's posture has not changed, the camera function is not operating, the screen is not displayed, it is locked, the battery level is decreasing slowly, or the temperature is low. This shortens the period during which the power transmission / reception device 100 operates in receiving mode, thus shortening the time from when the receiving device 200 is placed on the power transmission / reception device 100 until the power transmission / reception device 100 begins charging. Alternatively, if the detection unit 108 detects by any of the above-mentioned means that the power transmission / reception device 100 is in use, the power transmission / reception device 100 may lengthen the predetermined time. In this context, the power transmission / reception device 100 is in use when, for example, its posture changes, the camera function is operating, the screen is displayed, it is unlocked, the battery level is decreasing rapidly, or its temperature is high. As a result, when the power transmission / reception device 100 is in use, the period of operation in power receiving mode is extended, which suppresses the temperature rise of the power transmission / reception device 100 and prevents it from becoming inoperable due to overheating.

[0106] Furthermore, the closer the power transmission / reception device 100 is to the power transmission standby state, the shorter the predetermined time may be for the power transmission / reception device 100. "Close to the power transmission standby state" here means that the power transmission / reception device 100 is in a state where it can wirelessly supply power to the power receiving device 200. More specifically, "close to the power transmission standby state" means that, for example, the posture has not changed, the camera function is not operating, the screen is not displayed, it is locked, the battery level is decreasing slowly, the temperature is low, and so on, with a large number of these conditions being met. In other words, the more of these conditions are met, the shorter the predetermined time for the power transmission / reception device 100. This allows for a further reduction in the time from when the power receiving device 200 is placed on the power transmission / reception device 100 until the power transmission / reception device 100 begins charging, provided the power transmission / reception device 100 is ready to transmit power. Alternatively, the closer the power transmission / reception device 100 is to the power receiving standby state, the longer the predetermined time may be for the power transmission / reception device 100. In this context, "close to a power receiving standby state" refers to a state in which the power transmitting / receiving device 100 is being wirelessly charged, or a state in which the power transmitting / receiving device 100 is being used. For example, it refers to a state in which many of the following conditions are met: the orientation of the power transmitting / receiving device 100 has changed, the camera function is operating, the screen is displayed, it is unlocked, the battery level is decreasing rapidly, the temperature is high, etc. In other words, the more of these conditions that are met, the longer the power transmitting / receiving device 100 will operate for a predetermined time. As a result, if there is a high probability that the power transmitting / receiving device 100 is being used, the period of operation in power receiving mode will be extended, thus achieving power savings. In addition, the temperature rise of the power transmitting / receiving device 100 can be further suppressed, preventing a state in which it becomes inoperable due to overheating.

[0107] Here, several examples are shown for the predetermined time to be compared with the period of the power receiving mode. However, the power transmission and receiving device 100 may determine (decide or set) the predetermined time using only one example, or it may determine it by arbitrarily combining multiple examples.

[0108] [Sequence of Wireless Power Transmission System] Next, with reference to Figure 8, the processing sequence of the wireless power transmission system including the power transmission / receiving device 100 and the power receiving device 200 will be described.

[0109] Figure 8 shows an example of a communication sequence between the power transmission / receiving device 100 and the power receiving device 200 when the power receiving device 200 is in close proximity to the power transmission / receiving device 100 (at least when the power receiving device 200 is within the range indicated by the dashed line in Figure 1A).

[0110] First, the power transmission / reception device 100 is assumed to be operating in power reception mode (S1001). The power transmission / reception device 100 starts measuring the time it has been operating in power reception mode using the measuring unit 107 (S1002). At this point, the power reception device 200 is placed on top of the power transmission / reception device 100 (S1003).

[0111] When the power transmission / reception device 100 has been operating continuously in power reception mode for a predetermined period of time (S1004), it switches from power reception mode to power transmission mode (S1005). Then, the power transmission / reception device 100 executes power transmission mode processing.

[0112] The control unit 101 of the power transmission and reception device 100 transmits an Analog Ping (S1006), determines that an object is present near the antenna 105, and transmits a Digital Ping (S1007).

[0113] The power receiving device 200 detects the power transmitting and receiving device 100 upon receiving the Digital Ping (S1008). The power receiving device 200 then notifies the power transmitting and receiving device 100 of the received voltage of the Digital Ping using the Signal Strength Packet (S1009). Subsequently, the power transmitting and receiving device 100 and the power receiving device 200 proceed to the Configuration Phase (S1010).

[0114] In the Configuration Phase, the power receiving device 200 transmits the Identification Packet to the power transmitting / receiving device 100. Subsequently, the power receiving device 200 transmits the Configuration Packet to the power transmitting / receiving device 100. The power transmitting / receiving device 100 refers to this Packet and proceeds to the Negotiation Phase (S1011).

[0115] When the power receiving device 200 transitions to the Negotiation Phase, it sends a Specific Request Packet to the power transmitting and receiving device 100. Here, the power receiving device 200 specifies Guaranteed Load Power = 15 watts in the Specific Request Packet. The control unit 101 of the power transmitting and receiving device 100 authorizes the Guaranteed Load Power specified in the Specific Request Packet.

[0116] When the Negotiation Phase ends, the power transmission / reception unit 100 and the power receiving unit 200 transition to the Power Transfer Phase (S1012). The power transmission / reception unit 100 then begins charging the power receiving unit 200. The power transmission / reception unit 100 performs the charging process with an output that allows the charging unit 205 of the power receiving unit 200 to receive power at 15 watts.

[0117] When the power receiving unit 205 has finished receiving power, the power receiving device 200 sends an End Power Transfer Packet to the power transmitting / receiving device 100 (S1013). Upon receiving this packet, the power transmitting / receiving device 100 stops the charging process for the power receiving device 200 and exits the power transmission mode (S1014). Subsequently, the power transmitting / receiving device 100 resets the measurement of the continuous operation time in power receiving mode (S1015). After that, the power transmitting / receiving device 100 switches from power transmission mode to power receiving mode (S1016). The user removes the fully charged power receiving device 200 from the power transmitting / receiving device 100 (S1017).

[0118] Next, referring to Figure 9, the processing sequence of a wireless power transmission system including only the power transmission / receiving device 100 when nothing is in close proximity to the power transmission / receiving device 100 will be described.

[0119] Figure 9 shows an example of the processing sequence of the power transmission and receiving device 100 when nothing is in close proximity to it (at least when there is nothing in the area indicated by the dashed line in Figure 1A).

[0120] First, the power transmission / reception device 100 is assumed to be operating in power reception mode (S1101). The power transmission / reception device 100 starts measuring the time it has been operating in power reception mode using the measurement unit 107 (S1102).

[0121] When the power transmission / reception device 100 has been operating continuously in power reception mode for a predetermined period of time (S1103), it switches from power reception mode to power transmission mode (S1104). Then, the power transmission / reception device 100 executes power transmission mode processing.

[0122] The control unit 101 of the power transmission / reception device 100 transmits an Analog Ping, but determines that there is no object in the vicinity of the antenna 105 (S1105).

[0123] The power transmission and reception device 100 counts the number of times it determines that no object exists using the measurement unit 107 (S1106).

[0124] The power transmission / reception device 100 transmits Analog Ping again, but determines that there is no object in the vicinity of the antenna 105 (S1107).

[0125] The power transmission and reception device 100 again counts the number of times it has determined that no object exists using the measurement unit 107 (S1108).

[0126] When the detection unit 108 of the power transmission / reception device 100 detects that the number of times it has determined that no object is present has reached a predetermined number (in this case, 2 times) (S1109), the power transmission / reception device 100 resets the count value (S1110) and terminates the power transmission mode (S1111).

[0127] Subsequently, the power transmission / reception device 100 resets the measurement of the time of continuous operation in power reception mode (S1112) and switches from power transmission mode to power reception mode (S1113).

[0128] Next, with reference to Figure 10, the processing sequence of a wireless power transmission system including the power transmission / receiving device 100 and the non-compatible power receiving device (not shown) when a non-compatible power receiving device is located nearby will be described.

[0129] Figure 10 shows an example of a communication sequence between the power transmission / receiving device 100 and an incompatible power receiving device when the incompatible power receiving device is located nearby (at least when the incompatible power receiving device is within the range indicated by the dashed line in Figure 1A).

[0130] First, assume that the power transmission / reception device 100 is operating in power reception mode (S1201). The power transmission / reception device 100 starts measuring the time it has been operating in power reception mode using the measurement unit 107 (S1202). Now, assume that an incompatible power receiving device (not shown) is placed on the power transmission / reception device 100 (S1203).

[0131] When the power transmission / reception device 100 has been operating continuously in power reception mode for a predetermined period of time (S1204), it switches from power reception mode to power transmission mode (S1205). Then, the power transmission / reception device 100 executes power transmission mode processing.

[0132] The control unit 101 of the power transmission / reception device 100 transmits an Analog Ping (S1206), determines that an object is present near the antenna 105, transmits a Digital Ping (S1207), and waits for a response from an unsupported power receiving device (S1208).

[0133] An incompatible power receiving device cannot detect the power transmitting / receiving device 100 even if it receives a Digital Ping. Furthermore, an incompatible power receiving device does not notify the power transmitting / receiving device 100 of the received voltage of the Digital Ping via the Signal Strength Packet (S1209).

[0134] If the power transmission / reception device 100 fails to receive a Signal Strength Packet within a predetermined time (S1210), it will not be able to transition to the Configuration Phase and will terminate the power transmission mode (S1211). The predetermined time here is, for example, 70 milliseconds, the response time to Digital Ping as defined in the Qi standard.

[0135] Subsequently, the power transmission / reception device 100 resets the measurement of the time of continuous operation in power reception mode (S1212), and the power transmission / reception device 100 switches from power transmission mode to power reception mode (S1213).

[0136] Next, referring to Figure 11, the processing sequence of a wireless power transmission system including the power transmission / receiving device 100 and the power transmission device 300 when the power transmission / receiving device 100 is in close proximity to the power transmission device 300 will be described.

[0137] Figure 11 shows an example of a communication sequence between the power transmission / receiving device 100 and the power transmission device 300 when the power transmission / receiving device 100 is in close proximity to the power transmission device 300 (at least when the power transmission / receiving device 100 is within the range shown by the dashed line in Figure 1B).

[0138] First, assume that the power transmission / reception device 100 is operating in power reception mode (S1301). The power transmission / reception device 100 starts measuring the time it has been operating in power reception mode using the measuring unit 107 (S1302). Now, assume that the power transmission / reception device 100 is placed on the power transmission device 300 (S1303).

[0139] The control unit 301 of the power transmission device 300 sends an Analog Ping (S1304), determines that an object is present near the power transmission antenna 305, sends a Digital Ping (S1305), and waits for a response from the power transmission / reception device 100.

[0140] The power transmission / receiving device 100 detects the power transmission device 300 upon receiving the Digital Ping (S1306). The power transmission / receiving device 100 then notifies the power transmission device 300 of the received voltage of the Digital Ping via the Signal Strength Packet (S1307). Subsequently, the power transmission / receiving device 100 and the power transmission device 300 proceed to the Configuration Phase (S1308).

[0141] In the Configuration Phase, the power transmission / receiving device 100 transmits the Identification Packet to the power transmission device 300. Subsequently, the power transmission / receiving device 100 transmits the Configuration Packet to the power transmission device 300. The power transmission device 300 refers to this Packet and proceeds to the Negotiation Phase (S1309).

[0142] When the power transmission / receiving device 100 transitions to the Negotiation Phase, it sends a Specific Request Packet to the power transmission device 300. Here, for example, the power transmission / receiving device 100 specifies Guaranteed Load Power = 15 watts in the Specific Request Packet. The control unit 301 of the power transmission device 300 approves the Guaranteed Load Power specified in the Specific Request Packet.

[0143] When the Negotiation Phase ends, the power transmission device 300 and the power transmission / receiving device 100 transition to the Power Transfer Phase (S1310). The power transmission device 300 then begins charging the power transmission / receiving device 100. The power transmission device 300 performs the charging process with an output that allows the charging unit 110 of the power transmission / receiving device 100 to receive power at 15 watts.

[0144] When the charging unit 110 has finished receiving power, the power transmission / receiving device 100 sends an End Power Transfer Packet to the power transmission device 300 (S1311). Upon receiving this packet, the power transmission device 300 stops the charging process for the power transmission / receiving device 100 (S1312). The user then disconnects the fully charged power transmission / receiving device 100 from the power transmission device 300 (S1313).

[0145] In this embodiment, when a power receiving device 200 approaches the power transmitting / receiving device 100, the power transmitting / receiving device 100 can switch to power transmission mode (S1005) and begin supplying power to the power receiving device 200 once a predetermined time has passed since it began operating in power receiving mode (S1004). When the battery of the power receiving device 200 is fully charged, the power transmitting / receiving device 100 can terminate power transmission and return to power receiving mode. Furthermore, if nothing is approaching the power transmitting / receiving device 100, even if the power transmitting / receiving device 100 sends an Analog Ping in power transmission mode (S1105), no object will be detected. If the number of times no object is detected reaches a predetermined number, or if no object is detected within a predetermined time, the power transmitting / receiving device 100 can return to power receiving mode. Alternatively, if an incompatible power receiving device approaches the power transmitting / receiving device 100, even if the power transmitting / receiving device 100 sends a Digital Ping in power transmission mode (S1207), no response will be received. In that case, the power transmission / receiving device 100 can return to the power receiving mode. Also, when the power transmission / receiving device 100 is in close proximity to the power transmission device 300, the power transmission / receiving device 100 can receive a Digital Ping from the power transmission device 300 (S1305) while operating in the power receiving mode, and can receive power from the power transmission device 300.

[0146] According to this embodiment, the power transmission / receiving device 100 switches to power transmission mode when it has been operating continuously in power reception mode for a predetermined period of time. Furthermore, the power transmission / receiving device 100 switches to power reception mode when it has met predetermined conditions in power transmission mode. By repeating this process, when a power receiving device 200 is placed on the power transmission / receiving device 100, wireless charging of the power receiving device 200 can be performed when the power transmission / receiving device 100 is in power transmission mode. In other words, simply by the user placing the power receiving device 200, which is the device to be powered, on a predetermined position on the power transmission / receiving device 100, the power transmission / receiving device 100 can change its operating mode as appropriate and enable wireless power transmission.

[0147] Furthermore, according to this embodiment, when the power transmission / receiving device 100 is mounted on the power transmission device 300, wireless charging of the battery (not shown) of the power supply unit 102 of the power transmission / receiving device 100 can be performed when the power transmission / receiving device 100 is in power receiving mode.

[0148] Furthermore, if nothing is placed on the power transmission / reception device 100, or if a power receiving device that is not compatible with the power transmission / reception device 100 is placed on it, the transmission of unnecessary Analog Ping and Digital Ping can be reduced, thereby lowering the power consumption of the power transmission / reception device 100.

[0149] In this way, the power transmission and reception device 100 can appropriately change its operating mode.

[0150] <Embodiment 2> Some (or all) of the configurations in the above embodiment may be replaced with other configurations that perform similar functions, or omitted, or other configurations may be added.

[0151] Embodiment 2 describes an alternative configuration where the power transmission / receiving device 100 is in close proximity to the power transmission device 300. However, for the power transmission device 300 to transmit power to the power transmission / receiving device 100, the power transmission / receiving device 100 only needs to be within the power transmission range of the power transmission device 300 and does not need to be mounted on the power transmission device 300. In this embodiment, redundant explanations of the same or similar configurations and processes as in Embodiment 1 will be omitted.

[0152] [Power transmission mode processing of the power transmission and receiving device] The power transmission mode processing of the power transmission and receiving device 100 (S408 in Figure 5) will be explained using Figure 12.

[0153] Figure 12 is a flowchart showing a second example of the power transmission mode processing in a first example of the processing operation of the power transmission and receiving device 100.

[0154] The control unit 101 of the power transmission / reception device 100 starts a charging sequence based on the Qi standard, transitions to the Selection Phase (S601), and transmits an Analog Ping (S602).

[0155] The power transmission / reception device 100 performs object detection by detecting at least one of the voltage value and current value of the antenna 105 when an Analog Ping is transmitted (S603). If the power transmission / reception device 100 determines that there are no objects around the antenna 105 (N in S603), it counts the number of times it has determined that there are no objects around the antenna 105 (S604) and stores the counted number in the memory 106.

[0156] The power transmission and reception device 100 uses a detection unit 108 to detect whether the count value stored in the memory 106 is above a predetermined value or below a predetermined value (S605).

[0157] If the count value is less than a predetermined value (N in S605), the power transmission / reception device 100 returns to Selection Phase and transmits Analog Ping again (S602). If the count value is greater than or equal to a predetermined value (Y in S605), the power transmission / reception device 100 erases the count value stored in memory 106 (S606), stops power transmission (S622), and terminates the power transmission mode processing. The predetermined value here is, for example, one or two times, but it may be two or more times to check for changes in the Q value or to statistically analyze the Q value.

[0158] If the power transmission / reception device 100 determines that an object is present around the antenna 105 (Y in S603), it returns to the power receiving mode (S607). The power transmission / reception device 100 then waits for a predetermined period. This predetermined period is, for example, the sum of the 500 millisecond interval for object detection by Analog Ping as defined in the Qi standard and the 70 microseconds defined as the period for object detection by Analog Ping in the Qi standard. In this case, the power transmission / reception device 100 can receive at least one Digital Ping within the predetermined period.

[0159] If the power transmission / reception device 100 receives a Digital Ping within a predetermined period (Y in S608), it continues to operate in power reception mode. Specifically, the power transmission / reception device 100 transitions to the Ping Phase of power reception mode processing and transmits a Signal Strength Packet as a response to the Digital Ping. The power transmission / reception device 100 then sequentially transitions to the Configuration Phase, Negotiation Phase, and Power Transfer Phase, and executes the Qi standard power reception mode processing. Please refer to Figure 7 (from S430 onwards) and the above explanation with reference to Figure 7.

[0160] On the other hand, if the power transmission / reception device 100 does not receive a Digital Ping within a predetermined period (N in S608), it returns to power transmission mode (S609). Then, the power transmission / reception device 100 transitions to Selection Phase (S610) and transmits an Analog Ping (S611).

[0161] The power transmission / reception device 100 performs object detection by detecting at least one of the voltage value and current value of the antenna 105 when an Analog Ping is transmitted (S612). If the power transmission / reception device 100 determines that there are no objects around the antenna 105 (N in S612), it counts the number of times it has determined that there are no objects around the antenna 105 (S604) and stores the counted number in the memory 106.

[0162] The power transmission and reception device 100 uses a detection unit 108 to detect whether the count value stored in the memory 106 is above a predetermined value or below a predetermined value (S605).

[0163] If the count value is less than a predetermined value (N in S605), the power transmission / reception device 100 returns to Selection Phase and sends Analog Ping again (S602). If the count value is greater than or equal to a predetermined value (Y in S605), the power transmission / reception device 100 erases the count value stored in memory 106 (S606), stops power transmission (S622), and terminates the power transmission mode processing. The predetermined value here is, for example, one or two times, but is not limited to that.

[0164] If the power transmission / reception device 100 determines that an object is present around the antenna 105 (Y in S612), it switches to the Ping Phase (S613). In the Ping Phase, the power transmission / reception device 100 transmits a Digital Ping (S614).

[0165] Next, if the power transmission / reception device 100 is N in S615 and Y in S616, it proceeds to the Configuration Phase (S617). That is, if the power transmission / reception device 100 does not receive the End Power Transfer Packet but receives the Signal Strength Packet, it proceeds to the Configuration Phase (S617).

[0166] When the power transmission / reception device 100 receives an End Power Transfer Packet in the Ping Phase (Y in S615), it stops transmitting power (S622) and terminates the power transmission mode processing.

[0167] On the other hand, if the power transmission / reception device 100 is N in both S615 and S616, it cannot proceed to the Configuration Phase. In other words, if the power transmission / reception device 100 does not receive the End Power Transfer Packet in the Ping Phase and cannot receive the Signal Strength Packet, it cannot proceed to the Configuration Phase. In this case, the power transmission / reception device 100 counts the number of times it fails to receive the Signal Strength Packet using the measurement unit 107 (S604), and stores the counted number in the memory 106.

[0168] The power transmission and reception device 100 uses a detection unit 108 to detect whether the count value stored in the memory 106 is above a predetermined value or below a predetermined value (S605).

[0169] If the count value is less than a predetermined value (N in S605), the power transmission / reception device 100 returns to Selection Phase and sends Analog Ping again (S602). If the count value is greater than or equal to a predetermined value (Y in S605), the power transmission / reception device 100 erases the count value stored in memory 106 (S606), stops power transmission (S622), and terminates the power transmission mode processing. The predetermined value here is, for example, once, but is not limited to that.

[0170] The processes in S617 to S621 are the same as those in S422 to S426 shown in Figure 6, so their explanation will be omitted.

[0171] In Embodiment 2, the counting of the number of times Analog Ping determined that no object exists and the number of times Signal Strength Packet could not be received were described as a common flow, but this is not limited to this. The power transmission / reception device 100 may count each count independently and decide whether to retransmit Analog Ping or stop power transmission. Also, the power transmission / reception device 100 decides to stop power transmission based on the counting of the number of times Analog Ping determined that no object exists and the number of times Signal Strength Packet could not be received, but this is not limited to this. The power transmission / reception device 100 may make the above decision based on whether an object can be detected within a predetermined time after transmitting Analog Ping, or whether a Signal Strength Packet can be received within a predetermined time after transmitting Digital Ping. In other words, the power transmission and reception device 100 may decide whether to retransmit the Analog Ping or to stop power transmission.

[0172] [Sequence of Wireless Power Transmission System] Next, with reference to Figure 13, another example of a processing sequence of a wireless power transmission system including the power transmission / receiving device 100 and the power transmission device 300 when the power transmission / receiving device 100 is in close proximity to the power transmission device 300 will be described.

[0173] Figure 13 shows an example of a communication sequence between the power transmission / receiving device 100 and the power transmission device 300 when the power transmission / receiving device 100 is in close proximity to the power transmission device 300 (at least when the power transmission / receiving device 100 is within the range shown by the dashed line in Figure 1B).

[0174] First, the power transmission / reception device 100 is assumed to be operating in power reception mode (S1401). The power transmission / reception device 100 starts measuring the time it has been operating in power reception mode using the measurement unit 107 (S1402).

[0175] When the power transmission / receiving device 100 has been operating continuously in power receiving mode for a predetermined time (S1403), it switches from power receiving mode to power transmission mode (S1404). Then, the power transmission / receiving device 100 executes power transmission mode processing. Now, let's assume that the power transmission / receiving device 100 is in close proximity to the power transmission device 300 (S1405). Specifically, let's assume that the power transmission / receiving device 100 is placed on top of the power transmission device 300.

[0176] The control unit 101 of the power transmission / reception device 100 transmits an Analog Ping (S1406), determines that an object is present near the antenna 105, and switches from power transmission mode to power reception mode (S1407). The power transmission / reception device 100 then waits for a predetermined time (S1408). This predetermined time is, for example, the sum of the interval for object detection by Analog Ping as defined in the Qi standard, the period for object detection by Analog Ping, and the period until a response to Digital Ping is made.

[0177] Meanwhile, the power transmission device 300 transmits an Analog Ping, determines that an object exists (S1409), and transmits a Digital Ping (S1410).

[0178] When the power transmission / receiving device 100 receives a Digital Ping while in standby mode, it detects the power transmission device 300 (S1411). The power transmission / receiving device 100 then notifies the power transmission device 300 of the received voltage of the Digital Ping using a Signal Strength Packet (S1412). After that, the power transmission / receiving device 100 and the power transmission device 300 transition to the Configuration Phase (S1413).

[0179] In the Configuration Phase, the power transmission / receiving device 100 transmits the Identification Packet to the power transmission device 300. Subsequently, the power transmission / receiving device 100 transmits the Configuration Packet to the power transmission device 300. The power transmission device 300 refers to this Packet and proceeds to the Negotiation Phase (S1414).

[0180] When the power transmission / receiving device 100 transitions to the Negotiation Phase, it sends a Specific Request Packet to the power transmission device 300. For example, the power transmission / receiving device 100 specifies Guaranteed Load Power = 15 watts in the Specific Request Packet. The control unit 301 of the power transmission device 300 approves the Guaranteed Load Power specified in the Specific Request Packet.

[0181] When the Negotiation Phase ends, the power transmission device 300 and the power transmission / receiving device 100 transition to the Power Transfer Phase (S1415). The power transmission device 300 then begins charging the power transmission / receiving device 100. The power transmission device 300 performs the charging process with an output that allows the charging unit 110 of the power transmission / receiving device 100 to receive power at 15 watts.

[0182] When the charging unit 110 has finished receiving power, the power transmission / receiving device 100 sends an End Power Transfer Packet to the power transmission device 300 (S1416). Upon receiving this packet, the power transmission device 300 stops the charging process for the power transmission / receiving device 100 and stops the power transmission process (S1417). After that, the user disconnects the fully charged power transmission / receiving device 100 from the power transmission device 300 (S1418).

[0183] In this embodiment, the power transmission / receiving device 100 can appropriately start receiving power from the power transmission device 300 by transmitting an Analog Ping (S1406) and then providing a waiting time (S1408). Even if the object detected by Analog Ping is a power receiving device 200 other than the power transmission device 300, the power transmission / receiving device 100 can enter power transmission mode again after waiting for a predetermined time and start supplying power to the power receiving device 200.

[0184] According to this embodiment, the power transmission / reception device 100 enters power transmission mode when the time spent continuously operating in power reception mode reaches a predetermined time. When the power transmission / reception device 100 detects an object using Analog Ping in power transmission mode, it returns to power reception mode. The power transmission / reception device 100 waits in this state, and if it does not receive a Digital Ping during standby, it determines that the object detected by Analog Ping is a device operating in power reception mode, and returns to power transmission mode again. The power transmission / reception device 100 then executes power transmission mode processing, and enters power reception mode if predetermined conditions are met. On the other hand, if the power transmission / reception device 100 receives a Digital Ping during standby, it determines that the object detected by Analog Ping is a device operating in power transmission mode. In this case, the power transmission / reception device 100 remains in power reception mode and executes power reception mode processing. By repeating the above steps, the power transmission / reception unit 100 can wirelessly supply power to the power reception unit 200 when the power reception unit 200 is placed on the power transmission / reception unit 100, while operating in power transmission mode. Furthermore, when the power transmission / reception unit 100 is placed on the power transmission unit 300, even while operating in power transmission mode, the power transmission / reception unit 100 can appropriately switch to power reception mode and wirelessly charge the battery (not shown) of the power supply unit 102 of the power transmission / reception unit 100. At that time, the power transmission / reception unit 100 can send a Digital Ping to the power transmission unit 300 to avoid unintentionally causing adverse effects. In this way, the power transmission / reception unit 100 can appropriately change its operating mode.

[0185] <Embodiment 3> In the above embodiment, the power transmission / receiving device 100 was described as switching to the power transmission mode when the time spent continuously operating in the power reception mode reached a predetermined time (Y in S404) as a determination of switching to the power transmission mode. However, other configurations are also possible. In this embodiment, redundant explanations of the same or similar configurations and processes as in Embodiment 1 or Embodiment 2 are omitted.

[0186] The decision to switch to power transmission mode is made, for example, as follows: The power transmission / receiving device 100 switches to power transmission mode when it does not receive power during the power reception mode processing (Y in S437). Alternatively, the power transmission / receiving device 100 may switch to power transmission mode during the power reception mode processing, for example, when it is fully charged (Y in S435) and when it sends an End Power Transfer Packet (S436). This prevents the power transmission / receiving device 100 from entering power transmission mode while receiving power.

[0187] Furthermore, the power transmission / reception device 100 may switch to power transmission mode when the remaining power (battery level) of the battery (not shown) of the power supply unit 102 of the power transmission / reception device 100 is above a predetermined threshold. The predetermined threshold here is, for example, 50% of the battery capacity. This ensures that the power transmission / reception device 100 enters power transmission mode when the battery level is sufficiently high, thus preventing the battery of the power transmission / reception device 100 from becoming completely depleted.

[0188] Alternatively, the power transmission / reception device 100 may switch to power transmission mode when it is being charged via wire. This ensures that the power transmission / reception device 100 is in power transmission mode when being charged via wire, thereby mitigating the depletion of the battery power supply unit 102 of the power transmission / reception device 100.

[0189] Furthermore, the power transmission / reception device 100 may switch to power transmission mode when the detection unit 108 detects, by any of the means described above, that the power transmission / reception device 100 is not in use. In this context, "the power transmission / reception device 100 is not in use" means, for example, that the device's orientation has not changed, the camera function is not operating, the screen is not displayed, it is locked, the battery level is decreasing slowly, or the temperature is low. This ensures that the power transmission / reception device 100 enters power transmission mode when it is not in use, thereby suppressing the temperature rise of the power transmission / reception device 100 and preventing it from becoming inoperable due to overheating.

[0190] The above describes the case where the power transmission mode is selected as the decision to switch from power receiving mode to power transmission mode. However, if the power transmission / receiving device 100 is operating in power receiving mode and is receiving a Digital Ping in Ping Phase (S429), it may operate in power receiving mode without switching to power transmission mode. Alternatively, if the battery (not shown) of the power supply unit 102 of the power transmission / receiving device 100 is being wirelessly charged (S434), the power transmission / receiving device 100 may operate in power receiving mode without switching to power transmission mode. Furthermore, if the power transmission / receiving device 100 is operating in power receiving mode and is communicating identifier information and device configuration information with the power transmission device 300 in Configuration Phase (S431), it may operate in power receiving mode without switching to power transmission mode. Furthermore, if the power transmission / receiving device 100 is operating in power receiving mode and is negotiating with the power transmission device 300 in Negotiation Phase (S432), it may operate in power receiving mode without switching to power transmission mode. Also, if the power transmission / receiving device 100 is operating in power receiving mode and is receiving, for example, 15 watts of power from the power transmission device 300 in Power Transfer Phase (S433), it may operate in power receiving mode without switching to power transmission mode. This prevents the power transmission / receiving device 100 from switching to power transmission mode while receiving power.

[0191] Furthermore, the power transmission / reception device 100 may operate in receiving mode instead of switching to transmission mode when the remaining power (battery level) of the battery (not shown) of the power supply unit 102 of the power transmission / reception device 100 is below a predetermined threshold. The predetermined threshold here is, for example, 50% of the battery capacity. This prevents the power transmission / reception device 100 from entering transmission mode when the battery level is low, thus preventing the battery of the power transmission / reception device 100 from becoming completely depleted.

[0192] Alternatively, the power transmission / reception unit 100 may operate in receiving mode instead of switching to transmission mode when it is not being charged via wire. This prevents the power transmission / reception unit 100 from entering transmission mode when it is not being charged via wire, thus avoiding a rapid depletion of the battery power supply unit 102 of the power transmission / reception unit 100.

[0193] Furthermore, the power transmission / reception device 100 may operate in power reception mode without switching to power transmission mode if the detection unit 108 detects, by any of the above-mentioned means, that the power transmission / reception device 100 is in use. In this context, the power transmission / reception device 100 is in use if, for example, its posture has changed, the camera function is operating, the screen is displayed, it is not locked, the battery level is decreasing rapidly, or the temperature is high. As a result, the power transmission / reception device 100 does not enter power transmission mode when it is in use, which suppresses the temperature rise of the power transmission / reception device 100 and prevents it from becoming inoperable due to overheating.

[0194] Although several examples of determining whether to switch to the power transmission mode have been shown here, the power transmission and receiving device 100 may determine whether to switch to the power transmission mode using only one example, or it may determine whether to switch to the power transmission mode by arbitrarily combining multiple examples.

[0195] Furthermore, in this embodiment, an example has been described in which the power transmission mode is switched to when a condition other than whether the time of continuous operation in the power receiving mode has reached a predetermined time is met, but the invention is not limited to this. The power transmission and reception device 100 may switch to the power transmission mode when the time of continuous operation in the power receiving mode has reached a predetermined time and the above-mentioned other condition is met. Alternatively, even if the time of continuous operation in the power receiving mode has reached a predetermined time, the power transmission and reception device 100 may not switch to the power transmission mode and may continue to operate in the power receiving mode if the above-mentioned other condition is not met.

[0196] According to this embodiment, the power transmission and reception device 100 can appropriately switch from power reception mode to power transmission mode, and can appropriately start power transmission to the power reception device 200.

[0197] [Other Embodiments] The above embodiments are not limited to the WPC standard and can be applied to various other standards.

[0198] This disclosure can also be implemented by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be implemented by a circuit (for example, an ASIC or FPGA) that implements one or more functions.

[0199] Furthermore, some of the processes described in this disclosure with reference to the flowchart may be implemented in hardware. For example, a dedicated circuit can be automatically generated on the FPGA from a program to implement each step by using a predetermined compiler. Alternatively, a Gate Array circuit may be formed in the same way as the FPGA and implemented in hardware.

[0200] Furthermore, the following additional information is disclosed regarding the above embodiments.

[0201] [Note 1] A device comprising: a power transmission means for transmitting power wirelessly; a power reception means for receiving power wirelessly; and a selection means for selecting whether the power transmission means is in a first state in which it is operating or a second state in which the power reception means is operational, wherein the selection means switches from the second state to the first state based on the duration of the second state.

[0202] [Note 2] The apparatus according to Note 1, wherein the selection means switches from the second state to the first state when the time reaches a predetermined time in the second state.

[0203] [Appendix 3] The apparatus according to Appendix 2, further comprising setting means for setting the predetermined time based on the remaining battery level of the apparatus.

[0204] [Appendix 4] The apparatus according to Appendix 2 or 3, further comprising setting means for setting the predetermined time based on whether the apparatus is being used.

[0205] [Note 5] The apparatus according to any one of Notes 2 to 4, further comprising setting means for setting the predetermined time based on whether the apparatus is being charged via wire.

[0206] [Note 6] The apparatus according to any one of Notes 1 to 5, characterized in that, in the first state, if the number of times an object cannot be detected by transmitting Analog Ping by the power transmission means is predetermined or greater, the selection means switches from the first state to the second state.

[0207] [Note 7] The apparatus according to any one of Notes 1 to 6, characterized in that, in the first state, if the number of times the Signal Strength Packet cannot be received in response to the transmission of Digital Ping by the power transmission means exceeds a predetermined number, the selection means switches from the first state to the second state.

[0208] [Appendix 8] The apparatus according to any one of Appendix 1 to 7, characterized in that, when an End Power Transfer Packet is received in the first state, the selection means switches from the first state to the second state.

[0209] [Note 9] The apparatus according to any one of Notes 1 to 8, characterized in that, in the first state, if an object cannot be detected within a predetermined time, the selection means switches from the first state to the second state.

[0210] [Note 10] The apparatus according to any one of Notes 1 to 9, characterized in that, in the first state, if a response to the transmission of Digital Ping by the power transmission means is not received within a predetermined time, the selection means switches from the first state to the second state.

[0211] [Note 11] The apparatus according to any one of Notes 1 to 10, characterized in that, in the first state, if the voltage across the coil is greater than or equal to a predetermined voltage, the selection means switches from the first state to the second state.

[0212] [Note 12] The apparatus according to any one of Notes 1 to 11, characterized in that, in the second state, if the remaining battery level of the apparatus exceeds a predetermined amount, the selection means switches from the second state to the first state.

[0213] [Note 13] The apparatus according to any one of Notes 1 to 12, characterized in that, in the first state, if the remaining battery level of the apparatus is less than a predetermined amount, the selection means switches from the first state to the second state.

[0214] [Note 14] The apparatus according to any one of Notes 1 to 13, characterized in that, in the second state, if the apparatus is not being used, the selection means switches from the second state to the first state.

[0215] [Note 15] The apparatus according to any one of Notes 1 to 14, characterized in that, when the apparatus is being used in the first state, the selection means switches from the first state to the second state.

[0216] [Note 16] The apparatus according to any one of Notes 1 to 15, characterized in that, in the second state, when the apparatus is being charged by wire, the selection means switches from the second state to the first state.

[0217] [Note 17] The apparatus according to any one of Notes 1 to 16, characterized in that, in the first state, if the apparatus is not being charged by wire, the selection means switches from the first state to the second state.

[0218] [Note 18] A method performed by a device related to wireless power transmission, characterized by detecting the duration of a second state in which power can be received wirelessly, and switching from the second state to a first state in which power is transmitted wirelessly based on the duration.

[0219] [Appendix 19] A program for causing a computer to perform the method described in Appendix 18. The present invention is not limited to the above embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are attached to make the scope of the invention public.

[0220] This application claims priority based on Japanese Patent Application No. 2024-195606, filed on 8 November 2024, and all of its contents are incorporated herein by reference.

Claims

1. An apparatus comprising: a power transmission means for transmitting power wirelessly; a power reception means for receiving power wirelessly; and a selection means for selecting whether the power transmission means is in a first state in which it is operating or a second state in which the power reception means is operational, wherein the selection means switches from the second state to the first state based on the duration of the second state.

2. The apparatus according to claim 1, characterized in that the selection means switches from the second state to the first state when the time in the second state reaches a predetermined time.

3. The apparatus according to claim 2, further comprising setting means for setting the predetermined time based on the remaining battery level of the apparatus.

4. The apparatus according to claim 2, further comprising setting means for setting the predetermined time based on whether the apparatus is being used.

5. The apparatus according to claim 2, further comprising setting means for setting the predetermined time based on whether the apparatus is being charged via wire.

6. The apparatus according to claim 1, characterized in that, in the first state, if the number of times an object cannot be detected by transmitting Analog Ping by the power transmission means exceeds a predetermined number of times, the selection means switches from the first state to the second state.

7. The apparatus according to claim 1, characterized in that, in the first state, if the number of times the Signal Strength Packet is not received in response to the transmission of Digital Ping by the power transmission means exceeds a predetermined number, the selection means switches from the first state to the second state.

8. The apparatus according to claim 1, characterized in that, when an End Power Transfer Packet is received in the first state, the selection means switches from the first state to the second state.

9. The apparatus according to claim 1, characterized in that, if an object cannot be detected within a predetermined time in the first state, the selection means switches from the first state to the second state.

10. The apparatus according to claim 1, characterized in that, in the first state, if a response to the transmission of Digital Ping by the power transmission means is not received within a predetermined time, the selection means switches from the first state to the second state.

11. The apparatus according to claim 1, characterized in that, in the first state, if the voltage across the coil is greater than or equal to a predetermined voltage, the selection means switches from the first state to the second state.

12. The apparatus according to claim 1, characterized in that, in the second state, if the remaining battery level of the apparatus exceeds a predetermined amount, the selection means switches from the second state to the first state.

13. The apparatus according to claim 1, characterized in that, in the first state, if the remaining battery level of the apparatus is less than a predetermined amount, the selection means switches from the first state to the second state.

14. The apparatus according to claim 1, characterized in that, if the apparatus is not being used in the second state, the selection means switches from the second state to the first state.

15. The apparatus according to claim 1, characterized in that, when the apparatus is being used in the first state, the selection means switches from the first state to the second state.

16. The apparatus according to claim 1, characterized in that, in the second state, if the apparatus is being charged by wire, the selection means switches from the second state to the first state.

17. The apparatus according to claim 1, characterized in that, in the first state, if the apparatus is not being charged by wire, the selection means switches from the first state to the second state.

18. A method performed by a device related to wireless power transmission, characterized by detecting the duration of a second state in which power can be received wirelessly, and switching from the second state to a first state in which power is transmitted wirelessly based on the duration.

19. A program for causing a computer to perform the method described in claim 18.

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