Power receiving apparatus and method performed by power receiving apparatus

Abstract

The present application provides a power receiving apparatus and a method performed by a power receiving apparatus. A power transmitting apparatus (101) performs a detection process for detecting an object different from a power receiving apparatus (102), and performs a process for a parameter used in the detection process based on a voltage change of a voltage applied to a power transmitting unit (203).

Description

[0001] (This application is a divisional application of the application filed on May 10, 2021, with application number 202180037093.3 and title "Power Transmission Equipment, Power Receiving Equipment, Control Method and Procedure".) Technical Field

[0002] This invention relates to power transmission equipment, power receiving equipment, control methods, and procedures associated with wireless power transmission. Background Technology

[0003] In recent years, technologies used in wireless power transmission systems, such as wireless charging systems, have been extensively developed. Patent Document 1 describes power-transmitting and power-receiving devices that conform to the standards developed by the Wireless Power Consortium (WPC) (an organization for standardizing wireless charging) (hereinafter referred to as the "WPC Standard"). Furthermore, Patent Document 1 describes a calibration process defined by the WPC Standard, which aims to improve the detection accuracy of conductive objects (foreign objects) such as metal sheets.

[0004] In the calibration process, the received power and power loss in the receiving device are acquired in each of two different states. Power loss is derived as the difference between the transmitted power in the transmitting device and the received power in the receiving device. Then, using pairs of received power and power loss in these two states as parameters, the expected power loss is derived relative to the received power received from the receiving device during wireless power transmission. If the difference between the actual power loss and the expected power loss exceeds a predetermined value, it can be determined that power loss attributable to a foreign object exists; that is, a foreign object is present.

[0005] On the other hand, Universal Serial Bus Power Delivery (USB PD) is becoming increasingly popular as a standard for providing power intended for, for example, fast charging of batteries via wired connections. According to USB PD, control is implemented such that if the power supplied to the load increases, the voltage output to the load increases accordingly. In this way, even with increased power supply, the current remains low; therefore, losses and heat generation in the circuit are suppressed, and power can be supplied to the load while maintaining high efficiency.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2017-070074 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In wireless power transmission equipment, changing the input voltage to the power transmission unit, which includes a power transmission coil, alters the transmitted power. Before and after the input voltage change, the power loss of the receiving device changes in each state. Therefore, if foreign object detection is attempted after the input voltage change, using the received power and power loss obtained before the input voltage change as parameters, the accuracy of foreign object detection decreases.

[0011] The present invention provides a technique for suppressing a decrease in the accuracy of detection processing for detecting objects different from those of the receiving equipment, even when the input voltage to the power transmission unit in the power transmission equipment has changed.

[0012] Solution for solving the problem

[0013] According to one aspect of the present invention, a power transmission device has the following configuration. Specifically, the power transmission device includes: a power transmission component for wirelessly transmitting power to a power receiving device; an application component for applying the power for power transmission to the power transmission component; and a processing component for performing detection processing for detecting an object different from the power receiving device, wherein the processing component processes parameters used in the detection processing based on voltage changes of the voltage applied to the power transmission component.

[0014] The effects of the invention

[0015] According to the present invention, even when the input voltage to the power transmission unit in the power transmission equipment has changed, the decrease in accuracy of the detection processing used to detect objects different from those in the power receiving equipment can be suppressed.

[0016] Other features and beneficial effects of the invention will become apparent from the following description provided with reference to the accompanying drawings. Note that in the drawings, the same or similar components are given the same reference numerals. Attached Figure Description

[0017] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0018] Figure 1 This is a diagram illustrating an exemplary structure of a wireless charging system.

[0019] Figure 2 This is a block diagram illustrating an exemplary structure of a power transmission device according to a first embodiment.

[0020] Figure 3 This is a block diagram illustrating an exemplary structure of a powered device according to a first embodiment.

[0021] Figure 4A This is a flowchart illustrating an exemplary process of the power supply equipment according to the first embodiment.

[0022] Figure 4B This is a flowchart illustrating an exemplary process of the power supply equipment according to the first embodiment.

[0023] Figure 5A This is a flowchart illustrating an exemplary process of processing the powered device according to the first embodiment.

[0024] Figure 5B This is a flowchart illustrating an exemplary process of processing the powered device according to the first embodiment.

[0025] Figure 6 This is a diagram illustrating an exemplary flow of processes performed in a wireless charging system according to a first embodiment.

[0026] Figure 7 This is a diagram showing the communication sequence (7a) in the I&C phase, the communication sequence (7b) in the negotiation phase, and the communication sequence (7c) in the calibration phase.

[0027] Figure 8 This is a diagram showing an example of the parameters used in foreign object detection processing.

[0028] Figure 9 This is a diagram used to illustrate linear complementarity in foreign object detection processing.

[0029] Figure 10 This is a diagram illustrating an example of a table describing the relationship between the GP and the output voltage to the power supply unit according to the first embodiment, and an example of a table describing the relationship between the GP and the input voltage to the charging unit according to the first embodiment.

[0030] Figure 11 This is a diagram illustrating an example of a table describing the relationship between the GP and the input voltage to the charging unit according to the second embodiment.

[0031] Figure 12 This is a diagram illustrating an exemplary flow of the processes performed in a wireless charging system according to a second embodiment.

[0032] Figure 13A This is a flowchart illustrating an exemplary process of the power supply equipment according to a third embodiment.

[0033] Figure 13B This is a flowchart illustrating an exemplary process of the power supply equipment according to a third embodiment.

[0034] Figure 14A This is a flowchart illustrating an exemplary process of processing a powered device according to a third embodiment.

[0035] Figure 14B This is a flowchart illustrating an exemplary process of processing a powered device according to a third embodiment. Detailed Implementation

[0036] The embodiments of the present invention are described below with reference to the accompanying drawings. Note that the following embodiments are merely examples illustrating the technical concept of the present invention and are not intended to limit the invention to the structures and methods described in the embodiments.

[0037] <First Embodiment>

[0038] (System Architecture)

[0039] Figure 1 An exemplary structure of a wireless charging system (wireless power transmission system) according to this embodiment is shown. The system is configured to include a power-transmitting device 101 and a power-receiving device 102. Hereinafter, the power-transmitting device may be referred to as TX, and the power-receiving device may be referred to as RX. TX 101 is an electronic device that wirelessly transmits power to RX 102 placed on a charging station 103. RX 102 is an electronic device that receives power wirelessly transmitted from TX 101 and charges its internal battery. The following description is provided using the exemplary case of RX 102 being placed on the charging station 103. Note that it is sufficient for RX 102 to be within the range where TX 101 can transmit power during the power transmission from TX 101 to RX 102, and RX 102 does not necessarily need to be placed on the charging station 103.

[0040] It should also be noted that TX 101 and RX 102 may each have the function of performing applications other than wireless charging. An example of RX 102 is a mobile information device operating by means of a rechargeable battery, such as a laptop PC (personal computer), tablet PC, or smartphone. Furthermore, an example of TX 101 is an accessory device for charging the mobile information device. Note that TX 101 and RX 102 can be storage devices such as hard disk drives and memory devices, and can be information processing devices such as personal computers (PCs). Furthermore, TX 101 and RX 102 can be image input devices such as imaging devices (e.g., cameras or camcorders) and scanners, or image output devices such as printers, copiers, or projectors. Additionally, TX 101 can be a mobile information device. In this case, RX 102 can be another mobile information device, or it can be a wireless headset. Furthermore, RX 102 can be a car. Furthermore, TX 101 can be a charger installed in, for example, the console inside a car.

[0041] Furthermore, in this invention, a foreign object is a conductive object such as a metal sheet. However, objects that are essential components of RX 102 and articles incorporating RX 102, or TX 101 and articles incorporating TX 101, and that have the potential to generate heat in an unintended manner when subjected to power wirelessly transmitted from the power transmission coil, are not considered foreign objects. Note that in this invention, a foreign object can be a power receiving device different from the RX 102 to which power is transmitted.

[0042] Furthermore, although a TX 101 and an RX 102 are shown in the wireless charging system of this embodiment, the invention is not limited thereto. The invention can also be applied to, for example, a configuration in which multiple RX 102 receive power from a single TX 101 or separate TX 101s.

[0043] This system performs wireless power transfer using the electromagnetic induction method employed in wireless charging, based on the Wireless Power Consortium (WPC) standard. Specifically, TX 101 and RX 102 perform wireless power transfer between the power-feeding coil of TX 101 and the power-receiving coil of RX 102, based on the WPC standard. Note that the wireless power transfer method (contactless power transfer method) applied to this system is not limited to the methods defined in the WPC standard, and can be other methods such as electromagnetic induction, magnetic resonance, electric field resonance, microwave, and methods using lasers. Furthermore, although this embodiment assumes wireless power transfer for wireless charging, wireless power transfer can be performed for purposes other than wireless charging.

[0044] According to the WPC standard, the guaranteed power output to the load (e.g., charging circuit) of RX 102 when receiving power from TX 101 is defined by a value called the guaranteed power (hereinafter referred to as "GP"). GP represents the guaranteed power output to the load (e.g., charging circuit) of RX 102, even if the power transmission efficiency between the receiving and transmitting coils decreases due to changes in the positional relationship between TX 101 and RX 102. For example, with a GP of 5 watts, TX 101 controls power transmission even if the power transmission efficiency decreases due to changes in the positional relationship between the receiving and transmitting coils, allowing 5 watts to be output to the load inside RX 102.

[0045] According to this embodiment, TX 101 and RX 102 perform communication for power transmission / receiving control based on the WPC standard. The WPC standard defines multiple phases, including a power transmission phase and a phase prior to power transmission, and communication for power transmission / receiving control is performed in each phase. The phase prior to power transmission includes a selection phase, a ping phase, an identification and configuration phase, a negotiation phase, and a calibration phase. Note that the identification and configuration phase is referred to hereinafter as the I&C phase.

[0046] During the selection phase, TX 101 sends a simulated Ping intermittently and repeatedly, and detects that an object is placed on charging station 103 (e.g., RX 102 or a conductor sheet is placed on charging station 103). The simulated Ping is a detection signal used to detect the presence of an object. TX 101 sends the simulated Ping by applying voltage or current to the power supply coil. The voltage or current applied to the power supply coil changes when the state where no object is placed on charging station 103 changes to the state where an object is placed on charging station 103. TX 101 detects at least one of the voltage and current values ​​of the power supply coil when sending the simulated Ping, and determines that an object is present and transitions to the Ping phase when the voltage value drops below a certain threshold or the current value exceeds a certain threshold.

[0047] During the Ping phase, TX 101 sends a digital Ping that is more powerful than the analog Ping. The power of the digital Ping is sufficient to activate the control unit of RX 102, which is placed on charging station 103. RX 102 informs TX 101 of the magnitude of the received voltage. In this embodiment, RX 102 sends a signal strength packet (hereinafter referred to as "SS packet") to TX 101. TX 101 identifies the object detected in the selection phase as RX 102 by receiving the response (SS packet) from RX 102, which has received its digital Ping. Upon receiving notification related to the received voltage value, TX 101 transitions to the I&C phase.

[0048] During the I&C phase, TX 101 identifies RX 102 and obtains device configuration information (capability information) from RX 102. Therefore, RX 102 sends an identification packet (ID packet) and a configuration packet to TX 101. The ID packet includes the identification information of RX 102, and the configuration packet includes the device configuration information (capability information) of RX 102. Upon receiving the ID packet and configuration packet, TX 101 responds with an acknowledgment (ACK). The I&C phase then ends. In the subsequent negotiation phase, the value of GP is determined based on, for example, the value of GP requested by RX 102 and the power supply capability of TX 101.

[0049] In the calibration phase, the RX 102 notifies the TX 101 of the received power using the received power packet. At this time, the RX 102 provides notifications related to at least two different received powers. For example, the RX 102 provides notifications related to two received powers (i.e., the received power in the state where no load is connected and the received power in the state where a load is connected and power close to the GP value is received). At the same time, when the TX 101 receives each notification related to these received powers, it obtains its own transmitted power, derives the power loss based on the difference between the transmitted power and the received power, and stores the power loss in association with the received power. In the subsequent power transmission phase, the TX 101 performs a foreign object detection process for detecting foreign objects other than the power receiving device using the pair of received power and power loss stored in the above-described manner as parameters.

[0050] Now, a method of performing a foreign object detection process in the TX 101 using two pairs of received power and power loss as parameters will be described. The TX 101 stores the two pairs of received power and power loss via communication in the calibration phase. Assume that in these two pairs, one pair is "received power = RP1, power loss = PL1" and the other pair is "received power = RP2, power loss = PL2".

[0051] When performing the foreign object detection process in the power transmission phase, the TX 101 first obtains the current received power = P from the RX 102 received . Subsequently, the TX 101 derives the expected value PL of the power loss at this time by linear interpolation between two points (RP1, PL1) and (RP2, PL2) cal . Note that it is assumed that RP1 < RP2. Specifically, the expected value can be derived using the following Expression 1.

[0052] [Expression 1]

[0053] PL cal =

[0054] (PL2 - PL1) / (RP2 - RP1)·(P received - RP1)+PL1

[0055] Here, using the following Expression 2, the current power loss PL can be derived based on the current transmitted power P in the TX 101 transmitted and the received power = P notified from the RX102 received . When the current power loss PL exceeds a predetermined value compared to the expected value PL cal , the TX 101 determines that the power loss has increased as a result of power consumption caused by the foreign object value, that is, a foreign object has been detected.

[0056] [Expression 2]

[0057] PL = P transmitted -P received

[0058] According to the aforementioned method, the expected value of the current power loss is derived by linear complementarity when using a pre-acquired value of power loss as a parameter. This is referred to as power loss calibration. Note that instead of the power loss of RX 102, the object of calibration could be, for example, the power received by RX 102, or the power transmitted by TX 101. Furthermore, the method for deriving the expected value of power loss (i.e., the method of calibration) is not limited to linear complementarity, and could be, for example, nonlinear complementarity using power series, etc. Furthermore, three or more pairs of information (e.g., pairs of received power and transmitted power) can be used as parameters. An example of using three or more pairs of information as parameters is the linear complementarity of the broken lines connecting (RP1,PL1) and (RP2,PL2) and (RP2,PL2) and (RP3,PL3). Here, (RP3,PL3) is the third pair of information on received power and power loss, and RP2 <RP3。

[0059] During the power transmission phase, controls are performed to start and continue power transmission, and to stop power transmission due to the detection of foreign objects or a fully charged state. In this embodiment, the power transmission phase further includes processes for changing the GP (Power Controller), changing the power supply voltage of the power transmitting equipment, changing the output voltage to the load of the power receiving equipment, and re-acquiring and adding parameters used for requesting foreign object detection processing. Details of these processes will be explained later.

[0060] TX 101 and RX 102 perform the aforementioned WPC-based power transmission / receiving control communication by superimposing signals onto the transmitted power using the same antenna (coil) as the wireless power transmission. Note that TX 101 and RX 102 can use a different antenna (coil) than the one used for wireless power transmission for power transmission / receiving control communication. Examples of communication using a different antenna (coil) include Bluetooth-compliant... Low-power standard communication methods. Furthermore, wireless LANs (e.g., based on standards such as the IEEE 802.11 series) can be used. It can communicate using other communication methods such as ZigBee and NFC (Near Field Communication). It can also communicate at frequencies different from those used in wireless power transmission, using antennas (coils) different from those used in wireless power transmission.

[0061] (Equipment Structure)

[0062] Subsequently, a description of the structure of the power transmitting device 101 (TX 101) and the power receiving device 102 (RX 102) according to this embodiment is given. Note that the structures described below are merely examples; part (or all, depending on the case) of the described structure can be replaced by other structures that implement other similar functions, or omitted, and further structures can be added to the structures described below. Furthermore, a block mentioned in the following description can be divided into multiple blocks, and multiple blocks can be integrated into a single block.

[0063] Figure 2 This is a block diagram illustrating an exemplary structure of the TX 101 according to this embodiment. In one example, the TX 101 includes a control unit 201, a power supply unit 202, a power supply unit 203, a placement detection unit 204, a power supply coil 205, a communication unit 206, a notification unit 207, an operation unit 208, a memory 209, a timer 210, an input voltage setting unit 211, and a reacquisition request unit 212.

[0064] The control unit 201 controls the entire TX 101 by executing, for example, a control program stored in the memory 209. That is, the control unit 201 controls... Figure 2 The functional units shown are as follows. In addition, control unit 201 performs control related to power supply control in TX 101. Control unit 201 can also perform control for applications other than wireless power transmission. Control unit 201 is configured to include one or more processors such as a CPU and an MPU. Note that control unit 201 can be configured to include hardware dedicated to a specific process (such as an application-specific integrated circuit (ASIC)) or an array circuit (such as an FPGA) compiled to perform a predetermined process. Control unit 201 stores information to be stored during the execution of various types of processing in memory 209. Furthermore, control unit 201 can use timer 210 to measure time periods.

[0065] The power supply unit 202 provides the entire TX 101 with the power required by the control unit 201 to control the TX 101, as well as for power supply and communication. The power supply unit 202 is, for example, a commercial power source or a battery. The battery stores the power supplied from the commercial power source.

[0066] The power transmission unit 203 converts the DC or AC power input from the power supply unit 202 into AC frequency power in the frequency band used in wireless power transmission, and inputs this AC frequency power into the power transmission coil 205; as a result, electromagnetic waves are generated to energize the RX 102. Note that the frequency of the AC power generated by the power transmission unit 203 is, for example, about several hundred kHz (e.g., 110 kHz to 205 kHz). Based on instructions from the control unit 201, the power transmission unit 203 inputs AC frequency power into the power transmission coil 205 so that the power transmission coil 205 outputs electromagnetic waves for energizing the RX 102. Furthermore, the power transmission unit 203 controls the intensity of the output electromagnetic waves by adjusting one or both of the voltage (power transmission voltage) and current (power transmission current) to be input into the power transmission coil 205. Increasing the power transmission voltage or power transmission current enhances the intensity of the electromagnetic waves, while decreasing the power transmission voltage or power transmission current weakens the intensity of the electromagnetic waves. Furthermore, based on instructions from control unit 201, power supply unit 203 performs output control for AC frequency power, thereby starting or stopping power supply from power supply coil 205. Additionally, power supply unit 203 notifies control unit 201 of the current power supply. In this way, control unit 201 can be aware of the current power supply at any given time. Note that a configuration is permitted where an entity other than power supply unit 203 measures the power supply and provides notification to control unit 201.

[0067] The placement detection unit 204 detects whether an object is placed on the charging station 103 based on the WPC standard. Specifically, the placement detection unit 204 detects whether the object is placed on the interface surface of the charging station 103. The placement detection unit 204 detects at least one of the voltage and current values ​​of the power supply coil 205 when, for example, the power supply unit 303 sends a WPC standard analog Ping via the power supply coil 205. Note that the placement detection unit 204 can detect changes in impedance. Then, if the voltage drops below a predetermined voltage value, or if the current value exceeds a predetermined current value, the placement detection unit 204 can determine that the object is placed on the charging station 103. Note that the object is determined to be a powered device or another foreign object based on whether there is a predetermined response from RX 102 to the digital Ping subsequently sent by the communication unit 206. That is, if TX 101 receives a predetermined response, the object is determined to be a powered device (RX 102); otherwise, the object is determined to be an object different from a powered device.

[0068] Communication unit 206 performs the aforementioned WPC standard-based control communication with RX 102. Communication unit 206 communicates by modulating the electromagnetic waves output from power transmission coil 205 and sending information to RX 102. Furthermore, communication unit 206 acquires the information sent by RX 102 by demodulating the electromagnetic waves output from power transmission coil 205 and modulated by RX 102. In other words, communication unit 206 communicates by superimposing information onto the electromagnetic waves transmitted from power transmission coil 205.

[0069] The notification unit 207 uses, for example, any visual, auditory, or tactile method to notify the user of information. The notification unit 207 notifies the user, for example, the charging status of the TX 101 and related information. Figure 1 The status related to power transmission of the wireless power transmission system shown in TX 101 and RX 102. The notification unit 207 is configured to include, for example, a liquid crystal display, an LED, a speaker, a vibration generation circuit, and other notification devices.

[0070] The operation unit 208 has a receiving function for accepting operations performed by the user on the TX 101. The operation unit 208 is configured to include, for example, buttons, a keyboard, a voice input device such as a microphone, a motion detection device such as an accelerometer and a gyroscope, or other input devices. Note that a device integrating the notification unit 207 and the operation unit 208, such as a touchscreen, can be used.

[0071] Memory 209 stores various types of information, such as identification information and capability information, as well as control programs. Note that memory 209 can store information acquired by a functional unit different from control unit 201. Timer 210 measures time, for example, using an up-counting timer to measure the time elapsed since startup and a down-counting timer to count down from a set time. Under the control of control unit 201, input voltage setting unit 211 sets the input voltage for supplying power from power supply unit 202 to power delivery unit 203. Input voltage setting unit 211 includes a variable voltage unit.

[0072] Using communication unit 206, reacquisition request unit 212 requests RX 102 to reacquisition the parameters used in the foreign object detection process. The parameters used in the foreign object detection process represent one or more pairs of power received and power lost, as mentioned in the previous description during the calibration phase. Note that reacquisition request unit 212 can be configured to operate entirely or partially on a processor different from the processor of control unit 201, and can be implemented via a program operating on control unit 201. The function of reacquisition request unit 212 can be implemented by executing, for example, a program stored in memory 209.

[0073] Here, the power supply unit 202 and the input voltage setting unit 211 can exist as other devices external to TX 101. Examples of such external devices include power adapters that provide power based on the USB PD standard. In this case, the control unit 201 can control the input voltage setting unit 211 via communication using the USB PD standard.

[0074] Figure 3 This is a block diagram illustrating an exemplary structure of the RX 102 according to this embodiment. The RX 102 includes a control unit 301, a battery 302, a power receiving unit 303, a placement detection unit 304, a power receiving coil 305, a communication unit 306, a notification unit 307, an operation unit 308, a memory 309, and a timer 310. The RX 102 also includes an output power setting unit 311, a reacquisition indication unit 312, and a charging unit 313.

[0075] Control unit 301 controls the entire RX 102 by executing, for example, a control program stored in memory 309. That is, control unit 301 controls... Figure 3 The functional units shown are as follows. Furthermore, control unit 301 performs control related to power-on control in RX 102. Control unit 301 can also perform control for applications other than wireless power transmission. Control unit 301 is configured to include one or more processors such as CPU (Central Processing Unit) and MPU (Microprocessor Unit). Note that control unit 301 can be constructed from hardware dedicated to a specific process (such as Application-Specific Integrated Circuit (ASIC)). Furthermore, control unit 301 can be configured to include array circuitry (such as FPGA (Field Programmable Gate Array)) compiled to perform predetermined processes. Control unit 301 stores information to be stored during the execution of various types of processing in memory 309. Additionally, control unit 301 can use timer 310 to measure time periods.

[0076] Battery 302 provides the entire RX 102 with the power required by control unit 301 to control the various units of RX 102, as well as for power reception and communication. In addition, battery 302 stores the power received via power receiving coil 305.

[0077] In the receiving coil 305, an induced electromotive force is generated by electromagnetic waves emitted from the supply coil 205 of TX 101. The receiving unit 303 receives the power generated in the receiving coil 305. The receiving unit 303 receives the AC power generated in the receiving coil 305 through electromagnetic induction, converts the AC power into DC power or AC power of a predetermined frequency, and outputs the power to the charging unit 313 for charging the battery 302. That is, the receiving unit 303 provides power to the load in RX 102, and the charging unit 313 and the battery 302 are examples of such loads. The above-mentioned GP is the power output from the receiving unit 303. In addition, the receiving unit 303 notifies the control unit 301 of the current received power. In this way, at any given time, the control unit 301 can know the received power at that time. Note that it is permissible to use an entity other than the receiving unit 303 to measure the received power and notify the control unit 301 of the received power.

[0078] The placement detection unit 304 detects that RX 102 is placed on the charging station 103 based on the WPC standard. For example, the placement detection unit 304 detects at least one of the voltage and current values ​​of the receiving coil 305 when the receiving unit 303 receives a digital ping from the WPC standard via the receiving coil 305. For example, if the voltage value drops below a predetermined voltage threshold or the current value exceeds a predetermined current threshold, the placement detection unit 304 determines that RX 102 is placed on the charging station 103.

[0079] Communication unit 306 performs the aforementioned control communication with TX 101 based on the WPC standard. Communication unit 306 communicates with TX 101 by demodulating the electromagnetic waves input from the receiving coil 305 to obtain information transmitted from TX 101, and by load modulating the input electromagnetic waves to superimpose the information to be transmitted to TX 101 onto the electromagnetic waves. In other words, communication unit 306 communicates by superimposing information onto the electromagnetic waves transmitted from the transmitting coil of TX 101.

[0080] The notification unit 307 uses, for example, any visual, auditory, or tactile method to notify the user of information. The notification unit 307 notifies the user, for example, the charging status of the RX 102 and related information. Figure 1The status of power transmission related to the wireless power transmission system of TX 101 and RX 102 shown is illustrated. The notification unit 307 is configured to include, for example, a liquid crystal display, LEDs, a speaker, vibration generation circuitry, and other notification devices. The operation unit 308 has a receiving function for accepting operations performed by the user on RX 102. The operation unit 308 is configured to include, for example, buttons, a keyboard, a voice input device such as a microphone, a motion detection device such as an accelerometer and a gyroscope, or other input devices. Note that a device integrating the notification unit 307 and the operation unit 308, such as a touchscreen, can be used. As described above, the memory 309 stores various types of information such as identification information and device configuration information, as well as control programs. Note that the memory 309 can store information acquired by a functional unit different from the control unit 301. The timer 310 measures time, for example, using an upward counting timer for measuring the time period elapsed since the start-up time and a downward counting timer for counting downwards from a set time.

[0081] The charging unit 313 uses power supplied from the power receiving unit 303 to charge the battery 302. Furthermore, under the control of the control unit 301, the charging unit 313 starts or stops charging the battery 302, and further adjusts the power used during charging of the battery 302 based on its charging state. When the power used by the charging unit 313 changes, the power supplied from the power receiving unit 303 (i.e., the power received in the RX 102) also changes accordingly. As mentioned above, the charging unit 313 is a load in the RX 102. Note that the charging unit 313 and the battery 302 can also exist as other devices external to the RX 102. These devices could be, for example, devices that operate using power supplied based on the USB PD standard. In this case, the control unit 301 can obtain information about the amount of power required by the charging unit 313 via communication using the USB PD standard. Under the control of the control unit 301, the output power setting unit 311 sets the output voltage for supplying power from the power receiving unit 303 to the charging unit 313 (i.e., the load). The output power setting unit 311 includes a variable voltage unit.

[0082] Using communication unit 306, reacquisition instruction unit 312 instructs TX 101 to begin reacquisition of the parameters used in the foreign object detection process. The parameters used in the foreign object detection process represent the pair of power received and power loss mentioned earlier in the calibration phase description. Note that reacquisition instruction unit 312 can be configured to operate entirely or partially on a processor different from the processor of control unit 301, and can be implemented via a program operating on control unit 301. The function of reacquisition instruction unit 312 can be implemented by executing, for example, a program stored in memory 309.

[0083] (Processing flow)

[0084] An exemplary flow of the processing performed by TX 101 and RX 102 is then described.

[0085] [Handling in power transmission equipment]

[0086] Figure 4A and Figure 4B This is a flowchart illustrating an exemplary process performed by the TX 101. In the following text, Figure 4A and Figure 4B Collectively referred to as Figure 4A and 4B This process can be implemented, for example, by executing a program read from memory 209 by control unit 201 of TX 101. This process also includes retrieving the process from request unit 212. Note that at least a portion of the following processes can be implemented in hardware. In this case, the hardware can be implemented, for example, by automatically generating dedicated circuitry using gate array circuitry such as an FPGA from the program used to implement each processing step using a predetermined compiler. Furthermore, this process can be initiated in response to power-on of TX 101, in response to user input from TX 101 indicating the start of a wireless charging application, or in response to TX 101 receiving power when connected to a commercial power source. Note that this process can also be initiated by another trigger.

[0087] In the power supply / receiving related processing, TX 101 first performs the selection and ping phases defined by the WPC standard, and waits for RX 102 to be placed (S401). Specifically, TX 101 sends an analog ping according to the WPC standard in a repetitive and intermittent manner, and the placement detection unit 204 detects the presence of an object placed on the charging station 103 based on changes in current or voltage in the power supply coil 205. If an object is detected placed on the charging station 103, TX 101 sends a digital ping. Furthermore, if a predetermined response (signal strength packet) to the digital ping already exists, TX 101 determines that the detected object is RX 102 and that RX 102 is placed on the charging station 103. Upon detecting the placement of RX 102, TX 101 performs the I&C phase defined by the WPC standard, and uses the communication unit 206 to obtain identification information and device configuration information (capability information) from RX 102 (S402).

[0088] Figure 7 Communication sequence 7a describes an exemplary flow of communication during the I&C phase. During the I&C phase, RX 102 sends an identification packet (ID packet) (F701) to TX 101. The ID packet stores the manufacturer code and basic device ID as identification information for RX 102, as well as information elements enabling the specification of the appropriate version of the WPC standard as capability information for RX 102. RX 102 also sends a configuration packet (F702) to TX 101. The configuration packet includes the following as capability information for RX 102: a maximum power value specifying the maximum power that RX 102 can provide to the load, and information indicating whether the negotiation function of the WPC standard is provided.

[0089] Once TX 101 receives these packets, it sends an ACK (F703), and the I&C phase ends. Note that TX 101 can use methods other than the communication in the WPC standard I&C phase to obtain the identification information and device configuration information (capability information) of RX 102 from RX 102. Furthermore, the identification information of RX 102 can be a WPC standard wireless power ID, or any other identification information that enables the identification of the individual RX 102. Information other than the information described above can be included as capability information.

[0090] Return to Figure 4A and 4B TX 101 negotiates with RX 102 and determines GP (S403) through communication during the negotiation phase. Figure 7Communication sequence 7b describes an exemplary flow of communication during the negotiation phase. The GP is determined based on a specific request packet from RX 102 and a response from TX 101 to that specific request packet. First, RX 102 notifies TX 101 of the requested GP value (F711) by sending a specific request packet. RX 102 determines the requested GP value based on its own required power. In this embodiment, the requested GP value at this phase is, for example, 5 watts.

[0091] TX 101 determines whether to accept a request from RX 102 based on its own power transmission capability. If it accepts the request, it sends an ACK (positive response) to RX 102; otherwise, it sends a NAK (negative response) to RX 102. Note that... Figure 7 Section 7b describes an example of TX 101 sending an ACK (F712). When TX 101 sends an ACK, the value of GP is determined to be the same as the value requested by RX 102 and is stored in the memory of both TX 101 and RX 102. On the other hand, when TX 101 sends a NAK, the value of GP is a small default value (e.g., equal to or less than 5 watts). In one example, the default value is pre-stored in the memory of both TX 101 and RX 102. Note that the aforementioned method for determining GP is an example, and another method can be used to determine GP.

[0092] Return to Figure 4A and 4B The input voltage setting unit 211 of TX 101 determines the input voltage for supplying power from the power supply unit 202 to the power transmission unit 203 based on the GP determined in S403, and sets the input voltage on the power transmission unit 203 (S404). Note that this process also includes a process for waiting for the voltage to be stably input to the power transmission unit 203 after the input voltage setting unit 211 sets the input voltage on the power transmission unit 203. Figure 10Table 1001 shows an example of an input voltage determined based on GP. Referring to Table 1001, the input voltage setting unit 211 can, for example, set an input voltage of 5 volts for a determined GP of 5 watts, set an input voltage of 9 volts for a determined GP of 15 watts, and so on. Here, the values ​​in Table 1001 are input voltage values ​​predetermined based on the electrical characteristics of the power supply unit 203 of TX 101 for efficient power delivery and are stored, for example, in memory 209. Note that in the case of an external device where the power supply unit 202 and the input voltage setting unit 211 operate based on the USB PD standard, the input voltage setting unit 211 can obtain the values ​​in Table 1001 from the control unit 201 via communication. Alternatively, Table 1001 can be stored in memory 209 as a table specified by the USB PD standard.

[0093] Return to Figure 4A and 4B After the input voltage is set, TX 101 obtains the parameters used for foreign object detection processing through the processing in the calibration stage (S405). Figure 7 Communication sequence 7c describes an exemplary flow of communication during the calibration phase. RX102 sends a power packet (F721) via communication unit 306. The power packet includes a power value representing the current power received. TX101 stores the power information included in the power packet as parameters for foreign object detection processing and then returns an ACK (F722). As will be explained below, F721 and F722 are repeated at least twice.

[0094] For example, RX 102 provides notifications related to the received power in two different states: a state with no load connected, i.e., a state close to 0 watts; and a state with a load connected and receiving power close to the GP value. To provide these notifications, communication of the received power packet and ACK occurs twice, and information on both received power values ​​is stored in TX 101. Note that, in addition to the aforementioned notifications, notifications related to intermediate received power between the state close to 0 watts and the state receiving power close to the GP value are also permitted. In this embodiment, it is assumed that when the GP value exceeds 5 watts, notifications related to the received power are provided at power value intervals of approximately 5 watts. For example, when the GP value is 15 watts, notifications related to the received power are provided in states receiving four types of power (i.e., approximately 0 watts, approximately 5 watts, approximately 10 watts, and approximately 15 watts). Note that the power value intervals may not be constant and may not be 5 watts. TX 101 stores all the received power values ​​it is notified of in memory 209 as parameters used for foreign object detection processing.

[0095] Furthermore, RX 102 adds information expressing this meaning to the first power packet after the calibration phase begins. Specifically, the value of Mode included in the power packet is set to 1. Moreover, for the second and subsequent power packets in this calibration phase, the value of Mode is set to a value other than 1 (e.g., 2). In this way, TX 101 can identify the start of the calibration phase based on the value of Mode. Note that the above method for identifying the start of a calibration phase is an example; Mode can take other values, and identification can be based on values ​​other than Mode. Furthermore, the start can be identified based on another packet.

[0096] Once TX 101 recognizes the start of the calibration phase by receiving a power packet with a mode value of 1, TX 101 discards the parameters used for foreign object detection processing stored in memory 209. Then, TX 101 stores the power received from the power packet received from RX 102 and the power loss representing the difference between the power received and the power supplied in power supply unit 203 at that time, in association with each other, in memory 209. Note that instead of power loss, the power supplied can be stored in association with the power received, or both power loss and power supplied can be stored in association with the power received. Subsequently, when TX 101 receives a power packet with a mode value of 2, TX 101 additionally stores the power received in that packet and the power loss at that time, in association with each other, in memory 209.

[0097] Figure 8 Table 800 shows an example of the contents of the parameters used in the foreign object detection process stored in memory 209. For example, the information in row 801 indicates that the power loss is 0.6 watts when the power received in RX 102 is 0.1 watts, and is stored when a power packet (mode = 1) is received from RX 102. Subsequently, each time a power packet (mode = 2) is received from RX 102, TX 101 adds a row to table 800 (e.g., row 802). Note that, as described above, in the case of receiving a power packet with mode = 1, TX 101 clears the contents up to this point and then stores the row again starting from row 801.

[0098] Return to Figure 4A and 4BTX 101 begins foreign object detection processing and power supply (S406, S407). The foreign object detection processing in TX 101 is executed as follows: First, TX 101 periodically obtains information about the current received power from RX 102. Notifications related to the received power from RX 102 are provided for foreign object detection processing via, for example, a power packet with a mode value of 0. If TX 101 receives a power packet (mode = 0), TX 101 does not update the parameters used for foreign object detection processing (Table 800). Then, TX 101 uses... Figure 8 The parameters used in the foreign object detection processing in Table 800 are used to derive the expected power loss corresponding to the acquired power through linear interpolation between various points. Expression 1 described above can be used in the linear interpolation.

[0099] TX 101 calculates power loss based on the difference between the first measured power supplied after receiving power (current power supplied) and the received power. Then, TX 101 compares the difference between the calculated power loss and the expected value with a threshold. If the difference between the calculated power loss and the expected value exceeds the threshold, TX 101 determines that power loss is caused by a foreign object, such as a metal sheet, and determines that the foreign object is present within the power supply range. If the presence of a foreign object is determined to be within the power supply range, TX 101 uses control unit 201 to limit power supply. Specifically, control unit 201 controls power supply unit 203 to stop power supply or reduce the power supplied. Furthermore, control unit 201 can notify RX 102 of the presence of the foreign object via communication unit 206. Additionally, control unit 201 can notify RX 102 of the limitation on power supply.

[0100] The following are the parameters used in foreign object detection processing. Figure 8 The exemplary cases shown in rows 801 and 802 of Table 800 are used to provide specific instructions for foreign object detection processing. Figure 9 curve Figure 9 Points A and B in section a are obtained by plotting rows 801 and 802 in a graph representing the received power and power loss by axes, respectively. TX 101 derives the expected value of the power loss corresponding to the current received power by a linear complement represented by the straight line connecting points A and B. For example, with the current received power (RP) valued at 2.5 watts, the values ​​of rows 801 (RP1 = 0.1 watts, PL1 = 0.6 watts) and 802 (RP1 = 4.9 watts, PL2 = 1.6 watts) are applied to expression 1 above. In this case, the expected value of the power loss PL is as follows.

[0101] PL=(1.6-0.6) / (4.9-0.1)*(2.5-0.1)+0.6=1.1

[0102] Then, using the first measured power supply after receiving power as the current power supply, TX101 calculates the power loss based on the difference between the current power supply and the current received power (RP = 2.5 watts). If the difference between the power loss calculated in the above manner and the expected value (PL) of 1.1 watts exceeds a threshold, it is determined that there is power loss caused by a foreign object, and that a foreign object exists in the power supply range. Here, the threshold can be an absolute value such as 1 watt, or a relative value such as 50% of the expected value. Information related to this threshold is stored in memory 209. Furthermore, the threshold can be changed in a stepwise manner according to the expected values ​​of the received power and the power loss.

[0103] exist Figure 4A and 4B During power supply, TX 101 also receives GP negotiation from RX 102 (S408). If, as a result of the negotiation, the GP changes, TX 101 refers to... Figure 10 Table 1001 determines the input voltage to the power supply unit 203. If the current input voltage needs to be changed (if the determined input voltage is different from the current input voltage) ("Yes" in S409), the input voltage setting unit 211 changes the input voltage (S410). The reacquisition request unit 212 waits for the input voltage to stabilize (S410), and then sends a request for reacquiring the parameters used in the foreign object detection process to RX 102 (S411). On the other hand, if the current input voltage is not changed (if the determined input voltage is the same as the current input voltage) ("No" in S409), the processes in S410 and S411 are skipped. Subsequently, TX 101 waits for a predetermined time period to receive an instruction from RX 102 for reacquiring the parameters used in the foreign object detection process (S412). Here, the purpose of waiting for the reacquisition instruction from RX 102 within the predetermined time period is to provide RX 102, which receives the reacquisition request, with a time period to perform the process of sending the instruction for reacquiring the parameters used in the foreign object detection process.

[0104] Upon receiving an instruction from RX 102 to reacquire the parameters used for the foreign object detection process ("Yes" in S413), the process returns to S405, and TX 101 reacquires the parameters used for the foreign object detection process through the process in the calibration phase. Note that during the power-on period of TX 101, the system continuously monitors whether an instruction for reacquisition is received from RX 102. Then, upon receiving an instruction for reacquisition from RX 102, the process moves from S413 to S405, and TX 101 performs the reacquisition of the parameters used for the foreign object detection process. That is, regardless of whether the input voltage changes, upon receiving an instruction from RX 102 to reacquire the parameters used for the foreign object detection process ("Yes" in S413), TX 101 begins the reacquisition of the parameters used for the foreign object detection process. Furthermore, if GP is not updated in S408 and it is determined in S409 that the input voltage has not changed, the process in S412 (the process for waiting to receive the instruction for reacquisition) can be skipped. Furthermore, although the input voltage is changed in S409 based on the GP value determined through negotiation with RX 102, this is not intended to be limiting. For example, control unit 201 can acquire the power supplied to RX 102 and can set and change the input voltage to power supply unit 203 based on that power supply. Additionally, this can also be configured to change the input voltage based on the USB PD standard.

[0105] If no instruction for reacquiring the parameters used in the foreign object detection process is received from RX 102 ("No" in S413), power supply continues for a predetermined period of time (S414). Here, the predetermined period of time is, for example, 1 second. If no request to stop power supply is received during this power supply period and no foreign object is detected ("No" in S415), the process returns to S408, and the above process is repeated. If a request to stop power supply is received or a foreign object is detected ("Yes" in S415), TX 101 stops power supply (S416). Then, TX 101 determines whether to end the process (S417). If it is determined that the process should not end ("No" in S417), the process returns to S401, and the above process is repeated. If it is determined that the process should end ("Yes" in S417), the current process ends. For example, the determination of whether to end the process is based on the content of the operation performed by the user on the operation unit 208.

[0106] [Processing in power receiving equipment]

[0107] Subsequently, using Figure 5A and Figure 5B An exemplary flow of processing performed by the RX 102 is described below. Figure 5A and Figure 5B Collectively referred to as Figure 5A and 5B This process can be implemented, for example, by executing a program read from memory 309 via control unit 301 of RX 102. This process also includes retrieving the instruction unit 312. Note that at least a portion of the process described below can be implemented in hardware. In this case, the hardware can be implemented, for example, by automatically generating dedicated circuitry using gate array circuitry such as an FPGA from the program used to implement each processing step using a predetermined compiler. Furthermore, this process can begin in response to power-on of RX 102, in response to startup of RX 102 caused by power supplied from battery 302 or TX 101, or in response to an instruction from the user of RX 102 to begin a wireless charging application. Note that this process can also be started by another trigger.

[0108] After initiating the power supply / receiving related processing, RX 102 performs the selection and ping phases defined by the WPC standard and waits for itself to be placed on TX 101 (S501). RX 102 then detects its placement on the charging station 103 of TX 101 by, for example, detecting a digital ping from TX 101. Upon detecting the digital ping, RX 102 then sends an SS packet including the received voltage value to TX 101.

[0109] When RX 102 detects that it is placed on the charging station 103 of TX 101, it uses the communication unit 306 to perform the communication in the I&C phase described above and sends identification information and device configuration information (capability information) to TX 101 (S502). Then, RX 102 negotiates with TX 101 and determines GP through communication in the negotiation phase (S503). Specifically, as described in conjunction with the processing in the power supply equipment, based on Figure 7 The communication sequence 7b shows a specific request packet and the communication in the negotiation phase is based on the response to that specific request packet.

[0110] The output power setting unit 311 determines the output voltage for supplying power from the power receiving unit 303 to the charging unit 313 based on the GP determined in S503, and sets the output voltage on the charging unit 313 (S504). The process also includes a process for waiting for the voltage to be stably output to the charging unit 313 after the output power setting unit 311 sets the output voltage.

[0111] Figure 10Table 1002 shows an example of the output voltage determined based on GP. Referring to Table 1002, the output power setting unit 311 can, for example, determine an output voltage of 5 volts for a GP of 5 watts, an output voltage of 9 volts for a GP of 15 watts, and so on. Here, it is assumed that the values ​​in Table 1002 are predetermined values ​​based on the electrical characteristics of the charging unit 313 of RX 102 for efficient charging and are stored in memory 309. Note that in the case of an external device operating based on the USB PD standard, the output voltage value can be obtained from the charging unit 313 via communication, or it can be stored in memory 309 as a table specified by the USB PD standard. Note that in this embodiment, it is assumed that Table 1002 stored in RX 102 and Table 1001 stored in TX 101 have the same contents. For example, if both TX 101 and RX 102 conform to the USB PD standard, the tables may have the same contents. Note that the contents may conform to other standards.

[0112] Subsequently, RX 102 provides notification related to the power receiving information for the parameters used by TX 101 to acquire foreign object detection processing via the communication in the aforementioned calibration phase (S505). Then, RX 102 connects the charging unit 313, which serves as a load, to the power receiving unit 303 and begins power receiving in the power transmission phase (S506).

[0113] When receiving power wirelessly from TX 101, RX 102 acquires the power necessary for charging unit 313 (S507). This value can be stored in memory 309 in advance, or it can be acquired from an external device via communication if charging unit 313 is an external device. If the power required for charging unit 313 falls within the range of the current GP (No in S508), power reception continues without changing GP for a predetermined period of time (S515). The predetermined period of time is, for example, 1 second. Afterward, if charging unit 313 has completed charging battery 302, power reception stops (Yes in S516, S517), and the current process ends. Otherwise (No in S516), the process returns to S507 to continue charging.

[0114] Here, during the continued power reception in S515, RX 102 repeatedly and periodically notifies TX 101 of the current power reception. TX 101 detects foreign objects based on this power reception information. Power reception packets according to the WPC standard are used to provide notifications related to the current power reception. Power reception packets are also used in the communication during the aforementioned calibration phase. For this reason, RX 102 makes it possible to distinguish between notifications used to store parameters for foreign object detection processing in TX 101 during the calibration phase, and notifications related to the current power reception used for foreign object detection processing in TX 101. Specifically, this is done by setting the mode value of the power reception packet to 0. Note that a different value than the mode value used in the calibration phase can be used, or the aforementioned identification can be based on entities other than the mode value. For example, it is possible to identify this by using different types of packets in the calibration phase and the power transmission phase.

[0115] On the other hand, if the acquisition of the power required by the charging unit 313 necessitates a change in the GP ("Yes" in S508), RX 102 negotiates with TX 101 and changes the GP (S509). Here, if the GP will be set to a predetermined size or higher, RX 102 can perform device authentication with TX 101 via communication. By performing device authentication, the predetermined size or higher power, guaranteed to meet WPC standards and other standards, can be received only from TX 101. An example of device authentication is a challenge-response communication using electronic certificates.

[0116] Subsequently, the RX 102 determines the output voltage to the charging unit 313 based on the updated GP. (Refer to...) Figure 10 The output voltage is determined using Table 1002. If it is necessary to change the current output voltage ("Yes" in S510), the output power setting unit 311 changes the output voltage to the charging unit 313 and waits for the voltage to stabilize (S511). If it is not necessary to change the current output voltage ("No" in S510), the processing in S511 is skipped.

[0117] Subsequently, RX 102 waits to receive a request from TX 101 for re-acquiring the parameters used in the foreign object detection process for a predetermined period of time (S512). Assuming that in combination... Figure 7 The communication sequence 7b described is used after the communication for updating the GP is completed. Figure 4A and 4B If S409 receives "Yes", the predetermined time period in S512 is, for example, a time period longer than the time period required for TX 101 to complete the processing of S410 and S411. Note that it is assumed that the value of this predetermined time period is stored in memory 309 in advance.

[0118] If a request for reacquiring the parameters used in the foreign object detection process is received from TX 101, or if the output voltage is changed in S511 ("Yes" in S513), RX 102 sends an instruction to TX 101 to reacquiring the parameters used in the foreign object detection process (S514). Then, the process proceeds to S505, and the calibration phase process is performed again using TX 101. On the other hand, if no request for reacquiring the parameters used in the foreign object detection process is received from TX 101 and the output voltage is not changed in S511 ("No" in S513), the process proceeds to S515. The process from S515 onwards is as described above.

[0119] Here, the indication sent by RX 102 for reacquiring the parameters used in the foreign object detection process can be a WPC standard packet, or it can be another packet that TX 101 can recognize. Alternatively, if RX 102 receives a request from TX 101 for reacquiring the parameters used in the foreign object detection process, it can use an affirmative response (ACK) to that request as the indication for reacquisition. Furthermore, the indication sent by RX 102 for reacquiring the parameters used in the foreign object detection process can be the same as the packet indicating the start of the calibration phase. That is, RX 102 can send... Figure 7 The communication sequence 7c, F721, issues an instruction to reacquire the parameters used in the foreign object detection process. As a result, TX 101 clears the stored parameters used in the foreign object detection process and begins communication during the calibration phase. In other words, the parameters used in the foreign object detection process are reacquired.

[0120] Furthermore, despite Figure 5A and 5BThe process describes how, in the event that the input voltage GP has changed, an instruction can be issued to reacquire the parameters used in the foreign object detection process, but this is not intended to be limiting. For example, if it is determined in S508 that the input voltage GP will not change ("No" in S508), the process can proceed to S510 without skipping S509. In this way, regardless of the change in GP, ​​RX 102 issues an instruction to reacquire in response to receiving a request for reacquisition from TX 101 during power-on, and performs the reacquisition of the parameters used in the foreign object detection process ("Yes" in S513). This allows RX 102 to issue an instruction to reacquire even if TX 101 changes the input voltage without updating GP and issues a request to reacquire the parameters used in the foreign object detection process. Note that in this case, since RX 102 monitors the reception of the request for reacquisition during power-on, a configuration that skips S511 and S512 is allowed if the determination in S510 is "No".

[0121] [System Operation]

[0122] use Figure 6 The following provides information on the use of Figure 4A and 4B as well as Figure 5A and 5B A more detailed description of the operation sequences of TX 101 and RX 102 that have already been described. Figure 6 This is a diagram illustrating an exemplary flow of processes performed in a wireless charging system according to a first embodiment. Assuming that in Figure 6 In this context, time passes in a top-down direction. It is assumed that in the initial state, RX 102 is not placed on TX 101, and the load (charging unit 313) of RX 102 is not connected to the receiving unit 303. Furthermore, it is assumed that the power required by the charging unit 313 of RX 102 is initially 5 watts, and then increases to 15 watts after the power transfer phase begins.

[0123] First, TX 101 sends an analog Ping and waits for an object to be placed on charging station 103 (F601, S501). Once RX 102 is placed (F602), the voltage or current of the analog Ping changes (F603). Based on this change, the placement detection unit 204 of TX 101 detects that an object has been placed (F604). Upon detecting the placement of an object, TX 101 sends a digital Ping (F605). RX 102 detects that it is placed on TX 101 by receiving this digital Ping (F606). Furthermore, TX 101 detects that the object placed on charging station 103 is RX 102 via the response to the digital Ping. Subsequently, RX 102 sends identification information and device configuration information (capability information) to TX 101 via communication in the I&C phase (F607, S402, S502).

[0124] Subsequently, GP (F608, S403, S503) is determined between TX 101 and RX 102. Here, since RX 102 requests the initially required 5 watts, GP is 5 watts. Since GP is 5 watts, TX 101 sets the input voltage (the voltage input from the input voltage setting unit 211 to the power supply unit 203) to 5 volts (F609, S404) with reference to Table 1001. Similarly, RX 102 sets the output voltage (the voltage output from the output power setting unit 311 to the charging unit 313) to 5 volts (F610, S504) with reference to Table 1002.

[0125] Subsequently, TX 101 acquires parameters used for foreign object detection processing corresponding to 0 watts to 5 watts as GP through the processing in the calibration phase, and stores these parameters in memory 209 (F611, S405, S505). This processing in the calibration phase is performed with the input voltage of TX 101 at 5 volts and the output voltage of RX 102 at 5 volts. As a result, the content of the parameters used for foreign object detection processing acquired by TX 101 and stored in TX 101 is equivalent to, for example... Figure 9 curve Figure 9 a.

[0126] Subsequently, TX 101 begins foreign object detection and power supply (F612, S406, S407), and RX 102 begins receiving power (F612, S506), continuing power supply / receiving and foreign object detection at GP=5 watts. This is consistent with... Figure 4A and 4B The sequence S408→S409 is "No" → S412→S413 is "No" → S414→S415 is "No" → 408 corresponds to this cycle. This also corresponds to... Figure 5A and 5BThe cycle corresponds to "No" in S507 → S508 → "No" in S515 → S516 → S507. During power supply / receiving, charging unit 313 requires 15 watt-hours ("Yes" in F613, S507, and S508), and GP is updated to 15 watts between TX 101 and RX 102 (F614, S408, S509). Once GP has been updated to 15 watts, TX 101 changes the input voltage to 9 volts with reference to Table 1001 ("Yes" in F615, S409, S410) and sends a request to reacquire the parameters used for foreign object detection processing (F617, S411). On the other hand, RX 102 also changes the output voltage to 9 volts with reference to Table 1002 ("Yes" in F616, S510, S511) and sends an instruction to reacquire the parameters used for foreign object detection processing ("Yes" in F618, S512, S513, S514).

[0127] Since TX 101 receives an instruction to reacquire the parameters used in the foreign object detection process ("Yes" in F618, S412, S413), TX 101 begins the calibration phase process (S405). On the other hand, RX 102 also begins the calibration phase process (S514, S505). Therefore, the calibration phase process is performed again between TX 101 and RX 102, and the parameters used in the foreign object detection process corresponding to 0 watts to 15 watts (which is the GP at this time) are acquired and these parameters are held in TX 101 (F619, S405, S505). This calibration phase process is performed with the input voltage set by the input voltage setting unit 211 of TX 101 at 9 volts and the output voltage set by the output power setting unit 311 of RX 102 at 9 volts.

[0128] As mentioned earlier, at the start of the calibration phase, TX 101 clears the parameters used for foreign object detection processing held up to this point. Furthermore, in this embodiment, it is assumed that the parameters used for foreign object detection processing are acquired at 5-watt intervals. Therefore, information corresponding to 0 watts, 5 watts, 10 watts, and 15 watts is acquired as parameters used for foreign object detection processing. Additionally, at this time, the input voltage setting unit 211 of TX 101 and the output power setting unit 311 of RX 102 are each set to 9 volts as a GP-based voltage. That is, these two are in a state electrically different from the state in F611 where they are each set to 5 volts. Therefore, as a result of the calibration process in F619, information is acquired that... Figure 9 curve Figure 9 Different curves at points A and B in region a Figure 9Points A', B', C', and D' of b are stored in TX 101 as parameters used for foreign object detection processing. Then, by using... Figure 9 curve Figure 9 The parameters used for foreign object detection processing shown in b are for power supply / receiving and foreign object detection between TX 101 and RX 102 at GP=15 watts (F620, S406, S407, S506).

[0129] In the above operation, when GP changes from 5 watts to 15 watts, the input and output voltages in TX 101 and RX 102 change to 9 volts (F614 to F616), and the parameters used for foreign object detection processing (F619) are reacquired in this state. That is, even when the electrical states of both TX 101 and RX 102 have changed, the parameters updated according to the changed state are used in the foreign object detection processing. This allows for more accurate detection of foreign objects.

[0130] Note that although TX 101 in the foregoing embodiment sends a request to reacquire the parameters used for foreign object detection processing after changing the input voltage (S410, S411), this is not intended to be limiting. The input voltage can be changed within a predetermined time period after sending the request to reacquire the parameters used for foreign object detection processing. In this case, after receiving the request to reacquire the parameters used for foreign object detection processing ("Yes" in S513), RX 102 waits for the predetermined time period until the change of input voltage is completed on the TX 101 side, and then sends an instruction to reacquire the parameters used for foreign object detection processing (S514). This predetermined time period includes the period from setting the new input voltage until the input voltage stabilizes. In this implementation, the parameters used for foreign object detection processing can also be reacquired while the input voltage has changed (i.e., while the electrical state of TX 101 has changed). Note that, as stated above, it is permissible to wait for TX 101 to provide notification related to the completion of the input voltage change, rather than waiting for the predetermined time period. Alternatively, RX 102 can monitor the voltage received from TX 101 and determine that the change in the input voltage in TX 101 has been completed if the voltage received has changed significantly; in this case, no notification from TX 101 regarding the completion of the input voltage change is required. In any case, the parameters used for foreign object detection processing can be reacquired when the input voltage has changed (that is, when the electrical state of TX 101 has changed).

[0131] In addition, the TX 101 can Figure 8The parameters used for foreign object detection processing in Table 800 are stored in memory 209 in association with the information of the input voltage set when these parameters are acquired. At this time, if the start of the calibration phase is identified, TX 101 retains these parameters in Table 800 without clearing them. After the input voltage changes (S410), if the parameters used for foreign object detection processing associated with that input voltage have been retained, TX 101 replaces the parameters used for foreign object detection processing with the parameters used for foreign object detection processing retained in association with the changed input voltage. This can suppress the reacquisition of parameters used for foreign object detection processing multiple times under the same input voltage condition, and can correspondingly shorten the time period until charging is complete by continuing to supply power.

[0132] Furthermore, TX 101 can be configured to notify the user via notification unit 207 when it is necessary to reacquire the parameters used for foreign object detection processing. This notification informs the user that power supply for charging has been temporarily suspended for the purpose of reacquiring the parameters used for foreign object detection processing. For example, in a powered device where the LED is lit during charging of RX 102, there is a possibility that the LED will turn off when power supply for charging is temporarily stopped. In this case, the user can be informed that the off LED does not necessarily indicate a malfunction.

[0133] <Second Embodiment>

[0134] The first embodiment has been described with respect to the case where Table 1002 held in RX 102 and Table 1001 held in TX 101 have the same contents. The second embodiment will be described with respect to the case where the relationship between GP in TX 101 and the input voltage to power supply unit 203 differs from the relationship between GP in RX 102 and the output voltage to power supply unit 303. For example, instead of... Figure 10 Table 1002, RX 102 will Figure 11 Table 1102 is stored in memory 309. Furthermore, the following describes the scenario where the power required for the charging unit 313 of RX 102 is initially 5 watts, then increases to 10 watts after the power transfer phase begins, and then further increases to 15 watts. Note that the other structures are similar to those of the first embodiment.

[0135] Will use Figure 12 The operation sequence of TX 101 and RX 102 according to the second embodiment will be explained. Figure 12 This is a diagram illustrating an exemplary flow of processes performed in a wireless charging system according to a second embodiment. Assuming that in Figure 12 In the middle, time passes from top to bottom. The operation from the detection of placement until the 5-watt GP performs power supply / receive and foreign object detection processing is consistent with... Figure 6 (F601 to F612, S401 to S407, S501 to S506) are the same. In F612, the input voltage of TX 101 is 5 volts, and the output voltage of RX 102 is 5 volts.

[0136] When charging unit 313 requires 10 watts ("Yes" in F1201, S507, S508), GP is updated to 10 watts between TX 101 and RX 102 (F1202, S408, S509). Once GP has been updated to 10 watts, TX 101 maintains the input voltage at 5 volts with reference to table 1001 ("No" in F1203, S409) and waits for an instruction from RX 102 to reacquire the parameters used for foreign object detection processing (S412). On the other hand, RX 102 changes the output voltage to 9 volts with reference to table 1002 ("Yes" in F1204, S510, S511) and sends an instruction to reacquire the parameters used for foreign object detection processing ("Yes" in F1205, S512, S513, S514).

[0137] Upon receiving an instruction to reacquire the parameters used for the foreign object detection process, TX 101 begins the calibration phase process (S412, S413: "Yes", S405). Meanwhile, RX 102, which also sent the instruction to reacquire the parameters used for the foreign object detection process, begins the calibration phase process (S514, S505). Therefore, the calibration phase process is performed again between TX 101 and RX 102, and the parameters used for the foreign object detection process corresponding to 0 watts to 10 watts (which is the GP at this time) are acquired and maintained in TX 101 (F1206, S405, S505). This calibration phase process is performed with the input voltage set to 5 volts by the input voltage setting unit 211 of TX 101 and the output voltage set to 9 volts by the output power setting unit 311 of RX 102. The foreign object detection process performed by TX 101 during GP=10W power supply / receiving uses the parameters (F1207, S406, S407, S506) obtained in the calibration phase of the foreign object detection process.

[0138] Subsequently, when charging unit 313 requires 15 watts ("Yes" in F1208, S507, S508), GP is updated to 15 watts between TX 101 and RX 102 (F1209, S408, S509). Once GP has been updated to 15 watts, TX 101 changes the input voltage to 9 volts with reference to table 1001 ("Yes" in F1210, S409, S410) and sends a request to reacquire the parameters used for foreign object detection processing (F1212, S411). Alternatively, RX 102 maintains the input voltage at 9 volts with reference to table 1102 ("No" in F1211, S510) and waits for a request from TX 101 to reacquire the parameters used for foreign object detection processing (S512).

[0139] When RX 102 receives a request to reacquire the parameters used for the foreign object detection process ("Yes" in F1212, S512, S513), RX 102 sends an instruction to reacquire the parameters used for the foreign object detection process (F1213, S514). Since TX 101 receives the instruction to reacquire the parameters used for the foreign object detection process ("Yes" in F1213, S412, S413), TX 101 begins the calibration phase process (S405). On the other hand, RX 102, which has sent the instruction to reacquire the parameters used for the foreign object detection process, also begins the calibration phase process (S514, S505). Therefore, the calibration phase process is performed again between TX 101 and RX 102, and the parameters used for the foreign object detection process corresponding to 0 watts to 15 watts (which is the GP at this time) are acquired and held in TX 101 (F1214, S405, S505). This process in the calibration phase is performed with the input voltage of TX 101 at 9 volts and the output voltage of RX 102 at 9 volts. Using the parameters obtained as a result of the foreign object detection process, power supply / receiving and foreign object detection are performed between TX 101 and RX 102 at 15 watts GP (F1215, S406, S407, S506).

[0140] As described above, according to the second embodiment, when GP changes from 5 watts to 10 watts (F1202), the input voltage of RX 102 changes to 9 volts, while the input voltage of TX 101 remains at 5 volts (F1203, F1204). The parameters used for foreign object detection processing are reacquired when the input voltage of TX 101 is 5 volts and the input voltage of RX 102 is 9 volts (F1206). Furthermore, when GP changes from 10 watts to 15 watts (F1209), the input voltage of TX 101 changes to 9 volts, while the input voltage of RX 102 remains at 9 volts (F1210, F1211). Then, the parameters used for foreign object detection processing are reacquired when the input voltages of TX 101 and RX 102 are both 9 volts (F1214). That is, when the electrical state of one of TX 101 and RX 102 has changed, foreign objects are detected using parameters updated according to that state. In this way, foreign objects can be detected more accurately.

[0141] <Third Embodiment>

[0142] In the third embodiment, even if the input voltage of TX 101 and the output voltage of RX 102 remain unchanged when GP has been updated, the parameters used for foreign object detection processing are added. Figure 13A , Figure 13B and Figure 14A , Figure 14B The processing of TX 101 and RX 102 according to the third embodiment are shown respectively. In the following, Figure 13A and Figure 13B Collectively referred to as Figure 13A and 13B ,and Figure 14A and Figure 14B Collectively referred to as Figure 14A and 14B The difference from the first embodiment is that S1301 is added. Figure 4A and 4B The processing of TX 101 in the middle, and adding S1401. Figure 5A and 5B The processing of RX 102 in the process. Other structures are similar to those in the first embodiment.

[0143] The process used in the third embodiment, where the GP is updated from 5 watts to 10 watts, is now explained. First, the process performed between TX 101 and RX 102... Figure 7 Based on the communication result of communication sequence 7b, update GP (S408, S508, S509). In this case, based on Figure 10Tables 1001 and 1002 do not change the input voltage of TX 101 or the output voltage of RX 102 (No in S409 and No in S510). Therefore, TX 101 does not send a request to reacquire the parameters used for foreign object detection processing, and RX 102 does not send an indication to reacquire the parameters used for foreign object detection processing. At this time, RX 102 sends a request to add the parameters used for foreign object detection processing based on the updated GP (No in S513 and S1401). Furthermore, TX 101 adds the parameters used for foreign object detection processing based on this add request (No in S413 and S1301).

[0144] Here, an explanation is given regarding the addition of parameters used for foreign object detection processing. RX 102 receives approximately 10 watts of power as the updated GP by temporarily increasing the power received in power receiving unit 303, and notifies TX 101 of the current power received and the request to add parameters used for foreign object detection processing. Note that the notification related to the power received and the request to add parameters used for foreign object detection processing can be sent together in one packet, or they can be sent separately in different packets. For example, a power receiving packet with a mode value of 2, as described in the first embodiment, can be used. Upon receiving a power receiving packet with a mode value of 2, TX 101 adds a pair of power received and power loss values ​​to Table 800 (…). Figure 8 ).

[0145] TX 101 calculates the power loss based on the received power value along with the parameter addition request used for foreign object detection processing, and the current value of its own supplied power value, and adds this power loss as a parameter used for foreign object detection processing. For illustration, assume that TX 101 obtains the power value during the first calibration phase of S405. Figure 8 Lines 801 and 802, and obtain Figure 9 curve Figure 9 a. Next, assume that in S1301, 9.9 watts of received power are received along with a request to add parameters for the foreign object detection process, and the supplied power is, for example, 13.4 watts. In this case, line 803, including a power loss of 3.5 watts (which is the difference between the received power and the supplied power), is added as a parameter for the foreign object detection process. Line 803 is equivalent to... Figure 9 curve Figure 9 Point C in c. Thus, with the nonlinear change in the received power and power loss in RX 102, TX 101 can detect foreign objects more accurately.

[0146] Here, even when the GP is changed from 5 watts to 10 watts, the input voltage of TX 101 and the output voltage of RX 102 remain unchanged, therefore the electrical state remains unchanged. Thus, it is not necessary to... Figure 9 curve Figure 9 As in embodiment b, all parameters used for foreign object detection processing are retrieved again from 0 watts, and the already retrieved parameters can be reused. In this case, as described in the third embodiment, completing the addition process without re-retrieval of parameters can shorten the power supply interruption period for charging and end charging in a shorter time period.

[0147] Note that, under the updated GP extremely high condition, RX 102 can provide notifications related to the values ​​of multiple received power supplies, for example, at intervals of approximately 5 watts. TX 101 can derive the power loss corresponding to each of the multiple received power supplies and add multiple parameters used in the foreign object detection process. This increases the accuracy of the linear complementarity, thereby enabling more accurate detection of foreign objects.

[0148] <Other Embodiments>

[0149] This invention can be implemented by supplying a program for implementing one or more functions of the above embodiments to a system or device via a network or storage medium, and causing one or more processors in the computer of the system or device to read and execute the program. This invention can also be implemented by a circuit (e.g., an ASIC) for implementing one or more functions.

[0150] This invention is not limited to the embodiments described above, and various changes and modifications can be made within the spirit and scope of this invention. Therefore, the appended claims have been added to inform the public of the scope of this invention.

Claims

1. A power receiving device, comprising: A power receiving unit used to wirelessly receive power from power transmitting equipment; A communication unit for communicating with the power transmission equipment; as well as The unit is changed to alter the voltage. The communication unit sends a first power packet, including information representing a first power value, to the power transmission equipment. After sending the first power packet, the changing unit changes the voltage of the receiving device based on the authentication of the power transmitting device. After sending the first power packet and after changing the voltage of the receiving device, the communication unit sends a second power packet, including information representing a second power value, to the transmitting device. After sending the second power packet, the communication unit sends a third power packet, including information representing a third power value, to the power transmission equipment.

2. The power receiving equipment according to claim 1, wherein, The changing unit changes the voltage to be supplied to the load based on the power required by the load, and the load consumes the power already received by the receiving unit.

3. The power receiving equipment according to claim 2, further comprising: The negotiation unit is used to negotiate with the power transmission equipment to change the power transmission based on the power required by the load.

4. The power receiving equipment according to claim 1, wherein, When the first power packet is sent, a calibration process is initiated.

5. The power receiving equipment according to claim 4, wherein, The calibration process is initiated again when the second powered power packet is sent.

6. The power receiving equipment according to claim 4, wherein, The calibration process yields the parameters to be used in the foreign object detection process performed on the power transmission equipment.

7. The power receiving equipment according to claim 1, wherein, The authentication is based on electronic certificates.

8. A method performed by an electrical receiving device, comprising: A first power packet, including information representing the first power received value, is sent to the power transmission equipment. After sending the first power packet, the voltage of the power receiving device is changed based on the authentication of the power transmitting device; After changing the voltage of the receiving device, a second power packet including information representing a second power value is sent to the transmitting device; as well as After the second power packet is sent, a third power packet, including information representing the third power value, is sent to the power transmission equipment.

9. The method according to claim 8, wherein, When the first power packet is sent, a calibration process is initiated.

10. The method according to claim 9, wherein, The calibration process is initiated again when the second powered power packet is sent.

11. The method according to claim 9, wherein, The calibration process yields the parameters to be used in the foreign object detection process performed on the power transmission equipment.

Images