Receiver and wireless power supply system

Abstract

To provide a wirelessly powered receiver achieving both rapid operation of the receiver and stable continuation of the operation.SOLUTION: A receiver 200 wirelessly receives transmission power comprising an AC signal. The receiver 200 comprises: a rectifier unit 202 that rectifies the transmission power; a power management unit 203 that manages a rectified voltage from the rectifier unit 202; a charging unit 204 that is charged by an output voltage from the power management unit 203; and a control unit 205 that operates with power supplied from the charging unit 204 and controls the entire receiver 200. The charging unit 204 has a plurality of capacitors, charges one of the capacitors for a prescribed period of time from the start of receipt of the transmission power, and also charges another capacitor which is different from the one capacitor after the prescribed period of time.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a receiver and a wireless power supply system. [Background technology]

[0002] There is a technology relating to a charging device that includes a power acquisition means for charging a first power storage unit with an externally supplied voltage, and a power transfer means for transferring the power stored in the first power storage unit to a second power storage unit having a larger capacity than the first power storage unit for storage therein, and the power transfer means includes a voltage drop suppression unit for suppressing a voltage drop in the first power storage unit each time power is transferred from the first power storage unit to the second power storage unit (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-226130 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is known a wireless power supply system that supplies power almost continuously from a transmitter to a receiver by using microwaves. In such a wireless power supply system, there is a need to quickly secure an operating voltage for a control circuit that controls the receiver at the beginning of wireless power supply from the transmitter, and there is also a need to continue stable operation of the receiver even if the wireless power supply from the transmitter is interrupted.

[0005] However, the technology disclosed in Patent Document 1 relates to an electronic device that receives operating power from an external device using RFID technology. Therefore, since the operating power supplied from an external device in Patent Document 1 is not continuous, it is difficult to meet the above-mentioned needs.

[0006] An object of the present disclosure is to provide a technology for enabling a wirelessly powered receiver to operate quickly and continue to operate stably. [Means for solving the problem]

[0007] A receiver that wirelessly receives transmission power consisting of an AC signal, the receiver having a rectifier unit that rectifies the transmission power, a power management unit that manages the rectified voltage from the rectifier unit, a charging unit that is charged by the output voltage from the power management unit, and a control unit that operates with power supplied from the charging unit and controls the entire receiver, the charging unit having a plurality of capacitors, and charging one of the plurality of capacitors for a predetermined time from the start of reception of the transmission power, and after the predetermined time, also charging the other capacitors other than the one capacitor. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a technique for ensuring both rapid operation and stable continuation of operation of a wirelessly powered receiver. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an overall configuration of a wireless power supply system (WPT system) according to a first embodiment. [Diagram 2] 2 is a block diagram illustrating an example of the configuration of a transmitter and a receiver illustrated in FIG. [Diagram 3] 1 is a diagram showing an outline of a circuit configuration of a receiver according to a first embodiment. [Figure 4] 1 is a diagram showing a time transition of a power supply voltage of a charging unit in the receiver according to the first embodiment. FIG. [Diagram 5] FIG. 11 is a diagram showing an outline of the circuit configuration of a receiver according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In all the drawings explaining the embodiment, the same reference numerals are given to common components, and repeated explanations are omitted. Note that the following embodiment does not unduly limit the contents of the present disclosure described in the claims. In addition, not all of the components shown in the embodiment are essential components of the present disclosure. In addition, each figure is a schematic diagram and is not necessarily illustrated strictly.

[0011] In the following description, a "processor" refers to one or more processors. The at least one processor is typically a microprocessor such as a CPU (Central Processing Unit), but may be another type of processor such as a GPU (Graphics Processing Unit). The at least one processor may be a single-core or multi-core.

[0012] Furthermore, the at least one processor may be a processor in the broad sense, such as a hardware circuit (for example, a field-programmable gate array (FPGA) or an application specific integrated circuit (ASIC)) that performs part or all of the processing.

[0013] In the following explanation, information that gives an output for an input may be described using an expression such as "xxx table", but this information may be data of any structure or a learning model such as a neural network that generates an output for an input. Therefore, the "xxx table" may be called "xxx information".

[0014] Furthermore, in the following description, the configuration of each table is an example, and one table may be divided into two or more tables, or all or part of two or more tables may be one table.

[0015] In addition, in the following explanation, the processing may be described with the "program" as the subject, but since the program is executed by a processor to perform a specified processing step by appropriately using a memory unit and / or an interface unit, etc., the subject of the processing may be the processor (or a device such as a controller having the processor).

[0016] The program may be installed in a device such as a computer, or may be, for example, in a program distribution server or a computer-readable (e.g., non-transitory) recording medium. In the following description, two or more programs may be realized as one program, or one program may be realized as two or more programs.

[0017] In the following description, identification numbers are used as identification information for various objects, but other types of identification information (for example, identifiers including alphabetic characters or symbols) may be used instead.

[0018] In addition, in the following description, when describing elements of the same type without distinguishing between them, reference signs (or common signs among the reference signs) may be used, and when describing elements of the same type with distinction between them, the identification numbers (or reference signs) of the elements may be used.

[0019] In the following description, the control lines and information lines are those that are considered necessary for the description, and not all control lines and information lines in the product are necessarily shown. All components may be connected to each other.

[0020] <0 System Overview> The WPT system according to the present disclosure has a receiver that receives power transmitted from a transmitter based on a wireless power supply method and supplies the power to a device.

[0021] Although details will be described in the first embodiment, in the WPT system according to the present disclosure, microwave power (approximately continuous continuous wave (CW) of 920 MHz) is received by the antenna of the receiver, and the radio waves are converted into a DC voltage by a rectifier circuit functionally connected to the antenna. The DC voltage output from the rectifier circuit is controlled by a power management unit, and then the voltage is supplied to a charging unit (mainly a capacitor).

[0022] The power storage element constituting the charging unit is not particularly limited and may include a capacitor, a lithium ion battery, an electric double layer capacitor, a ceramic capacitor, etc. In the WPT system according to the present disclosure, the charging unit will be described as mainly including a capacitor.

[0023] The voltage supplied from the power management unit is supplied to the charging unit when the voltage stored in the charging unit is less than a predetermined value. When the charging unit charges the battery up to the predetermined voltage, the power output from the power management unit is supplied to the microcomputer.

[0024] Here, the operating power of the microcomputer that controls the entire receiver in wireless power supply depends on the microwave power received by the receiver. In the WPT system according to the present disclosure, the charging unit mainly includes a capacitor, so that at the beginning of wireless power supply from the transmitter, a sufficient voltage for operating the microcomputer is not stored in the charging unit. For this reason, it is desirable to store a sufficient voltage in the charging unit as soon as possible after the start of wireless power supply from the transmitter, and operate the microcomputer as soon as possible.

[0025] Considering this point of view, it is preferable to reduce the electrostatic capacitance (hereinafter simply referred to as "capacity") of the capacitor constituting the charging unit and rapidly charge the charging unit to accumulate a predetermined voltage in the capacitor.

[0026] On the other hand, since the power supply state of wireless power supply depends on the environment, it is difficult to stably supply a constant amount of power, and the amount of power supply varies greatly over time. In addition, the amount of power supply can also change in solar cell and laser-based wireless power supply. Even in such a situation where the power supply state is unstable, it is necessary to continue stable power supply to the receiver's microcomputer and further to the sensor device of the receiver.

[0027] Considering this point of view, it is preferable to increase the capacity of the capacitor constituting the charging section so that power supply to the microcomputer and the like can continue as stably as possible even if a change occurs in the power supply state.

[0028] As described above, there are somewhat contradictory viewpoints regarding the capacitance of the capacitor that constitutes the charging unit in the WPT system according to the present disclosure, and these are in a trade-off relationship.

[0029] Therefore, in the WPT system according to the present disclosure, multiple capacitors are provided in the charging section of the receiver, and one of the multiple capacitors is charged for a predetermined time from the start of wireless power supply from the transmitter (start of receiving transmission power), and charging is performed first until the operating power of the microcomputer, etc. is secured. Next, after the predetermined time has elapsed, the capacitors other than the one capacitor are also charged, and charging is performed by increasing the capacity of the entire charging section. This allows stable power supply to the microcomputer, etc., and even if the power supply state from the transmitter changes, stable power supply to the microcomputer, etc. can be continued.

[0030] In this case, it is preferable that the capacitance of the one of the capacitors is equal to or smaller than the other capacitors (hereinafter referred to as "other capacitors"). This allows charging to be performed more quickly to ensure the operating power of the microcomputer, etc. within a predetermined time from the start of reception of transmission power, and as a result, the receiver can start operating more quickly. On the other hand, by making the capacitance of the other capacitor equal to or larger than the capacitance of the one capacitor, if the other capacitor is sufficiently charged after the predetermined time has elapsed, it is possible to continue supplying power to the microcomputer, etc. more stably even if the power supply state from the transmitter changes.

[0031] It goes without saying that the specific configuration of the WPT system according to the present disclosure is not limited to the above.

[0032] <1. First embodiment> <1.1 Overall system configuration> FIG. 1 is a diagram showing the overall configuration of a WPT system 1 according to the first embodiment.

[0033] The WPT system 1 shown in Fig. 1 includes, for example, a transmitter 100, a receiver 200, a first information processing device 300, and a second information processing device 400. The WPT system 1 shown in Fig. 1 is used in, for example, a building or a factory.

[0034] In this specification, the transmitter 100 is a (power) transmitter 100 in the sense of wirelessly transmitting power, and similarly, the receiver 200 is a (power) receiver 200 in the sense of wirelessly receiving power. As described later, the transmitter 100 may transmit, for example, information on the state of the receiver 200 or information on a measurement result by a sensor to the transmitter 100 as a data signal, and the transmitter 100 may receive such a data signal. In this case, the transmitter 100 is a receiver that receives a data signal, and the receiver 200 functions as a transmitter that transmits a data signal.

[0035] 1 shows an example in which the WPT system 1 includes three transmitters 100, but the number of transmitters 100 included in the WPT system 1 is not limited to three. The number of transmitters 100 included in the WPT system 1 may be two or less, or may be four or more.

[0036] 1 shows an example in which the WPT system 1 includes seven receivers 200, but the number of receivers 200 included in the WPT system 1 is not limited to seven. The number of receivers 200 included in the WPT system 1 may be six or less, or eight or more.

[0037] 1 shows an example in which the WPT system 1 includes two first information processing devices 300, but the number of first information processing devices 300 included in the WPT system 1 is not limited to two. The number of first information processing devices 300 included in the WPT system 1 may be one, or three or more.

[0038] The transmitter 100 transmits, for example, a power supply signal or a data signal to the receiver 200. The transmitter 100 transmits the power supply signal to the receiver 200 by radio waves in the 920 MHz band, for example. The transmitter 100 transmits the data signal to the receiver 200 by radio waves in the 2.4 GHz band, for example. The transmitter 100 may transmit the data signal by radio waves in the 920 MHz band.

[0039] The power transmission signal transmitted from the transmitter 100 may be, for example, a continuous wave (CW) having a predetermined power. The frequency band of the power transmission signal is, for example, a 920 MHz band, taking into consideration the distance between the transmitter 100 and the receiver 200. If the frequency band is higher than the exemplified frequency band, it may not be possible to supply the predetermined power that allows the receiver 200 to operate unless the distance between the transmitter 100 and the receiver 200 is shortened, so an appropriate frequency band can be determined by taking into consideration a practical range (for example, the distance between the transmitter 100 and the receiver 200 is several meters).

[0040] In this case, the laws of the country in which the WPT system 1 is installed may impose restrictions on the intermittent transmission of a power transmission signal having a predetermined power. As an example, if the power transmission signal from the transmitter 100 falls under the provisions of the radio station stipulated in the Radio Law of Japan (regardless of whether a license is obtained or not), it may be necessary to provide a certain pause period for the power transmission signal based on the Radio Law. In this case, the power transmission signal cannot be considered as a continuous wave when considered on a certain time axis. However, since it is essential to provide a pause period and this pause period is sufficient if it is short, the power transmission signal transmitted from the transmitter 100 can be considered as a substantially continuous continuous wave. The method of setting this pause period itself can be selected arbitrarily. In other words, if there are legal restrictions as described above, an arbitrary pause period may be set within a range that complies with these restrictions. Also, if it is necessary to provide a pause period because the temperature of the transmitter increases due to continuous operation of the transmitter, an arbitrary pause period may be set to keep the temperature of the transmitter constant. The term "arbitrary" here means that the duration of the suspension period itself, and if the suspension period is repeated, the timing of the repetition (whether it is periodic or not may be based on legal restrictions, etc.), can be set arbitrarily.

[0041] The transmitter 100 may, for example, feed power to one receiver 200 or to multiple receivers 200. The transmitter 100 may, for example, transmit a data signal to one receiver 200 or to multiple receivers 200. The transmitter 100 may, for example, transmit the same data signal as another transmitter 100, or may transmit a data signal different from that of the other transmitters 100. The transmitter 100 may, for example, transmit a predetermined command signal as a data signal to the receiver 200, or may transmit a preset signal as a data signal to the receiver 200.

[0042] The transmitter 100 receives, for example, a data signal transmitted from the receiver 200. The transmitter 100 may receive, for example, a data signal transmitted from one receiver 200, or may receive data signals transmitted from a plurality of receivers 200. The transmitter 100 transmits the data signal transmitted from the receiver 200 to the first information processing device 300. The transmitter 100 transmits information related to the state of the transmitter 100 to the first information processing device 300.

[0043] The receiver 200 receives, for example, a power supply signal and / or a data signal transmitted from the transmitter 100. For example, when the receiver 200 has a charging unit, the receiver 200 converts the power supply signal transmitted from the transmitter 100 into electric power and stores the converted electric power in the charging unit. For example, when the receiver 200 has a predetermined sensor, the receiver 200 converts the power supply signal transmitted from the transmitter 100 into electric power and drives the sensor with the converted electric power.

[0044] The receiver 200 transmits, for example, information relating to the state of the receiver 200 or information relating to the measurement results of a sensor to the transmitter 100 as a data signal.

[0045] The first information processing device 300 is an information processing device that monitors the operation of the transmitter 100 and the receiver 200 housed in the WPT system 1. For example, the first information processing device 300 determines whether the transmitter 100 or the receiver 200 is in a preset state based on information about the state of the transmitter 100 and the receiver 200 transmitted from the transmitter 100. If it is determined that the transmitter 100 or the receiver 200 is in a preset state, the first information processing device 300 transmits predetermined information to the second information processing device 400.

[0046] In addition, the first information processing device 300 accumulates information about the transmitter 100 and the receiver 200 accommodated in the WPT system 1. For example, the first information processing device 300 stores information about the states of the transmitter 100 and the receiver 200 transmitted from the transmitter 100 in a storage unit provided in the first information processing device 300.

[0047] In addition, the first information processing device 300 controls the operation of the transmitter 100 accommodated in the WPT system 1.

[0048] The second information processing device 400 is an information processing device operated by an administrator of the WPT system 1. When the second information processing device 400 receives a notification from the first information processing device 300 that the transmitter 100, the receiver 200, or both of them housed in the WPT system 1 are in a predetermined state, the second information processing device 400 presents to the user that the transmitter 100, the receiver 200, or both of them are in the predetermined state.

[0049] Moreover, the second information processing device 400 analyzes information on the status of the transmitter 100 and the receiver 200 stored in the first information processing device 300, and presents predetermined information to the user. The predetermined information is, for example, the following. Information regarding placement of transmitter 100 Information regarding the placement of the receiver 200 Power consumption information Power intensity information

[0050] <1.2 Transmitter and receiver configuration> FIG. 2 is a block diagram showing an example of the configuration of the transmitter 100 and the receiver 200 shown in FIG. 1. As shown in FIG. 2, the transmitter 100 and the receiver 200 are, for example, spaced apart from each other at a predetermined interval. For example, the transmitter 100 and the receiver 200 are installed at a distance of about several meters apart. Specifically, for example, the transmitter 100 is fixedly installed at a predetermined high position provided in a high place indoors, for example, on a ceiling or a wall. The receiver 200 is installed in a predetermined device indoors, or placed near a device that requires power supply. The receiver 200 may also be carried by a user. The transmitter 100 transmits a power supply signal to the receiver 200 by radio waves of a predetermined frequency, for example, 920 MHz band. The receiver 200 converts the power supply signal transmitted from the transmitter 100 into power, and charges the device with the converted power, or supplies the converted power to the predetermined device.

[0051] The transmitter 100 includes, for example, an oscillator 101, a transmitting antenna 102, a microcomputer (controller) 103, a data transceiver 104, and a data transmitting / receiving antenna 105. The oscillator 101, the microcomputer 103, and the data transceiver 104 may be mounted on, for example, a PCB (printed circuit board).

[0052] The oscillator 101 oscillates a signal in a predetermined frequency band, for example, the 920 MHz band. The oscillated signal may be amplified and unnecessary frequency components may be removed, if necessary.

[0053] The transmitting antenna 102 is formed so as to be capable of efficiently transmitting radio waves in the 920 MHz band, for example. The transmitting antenna 102 radiates a signal oscillated by an oscillator 101 as a power supply signal.

[0054] The microcomputer 103 controls the operation of the transmitter 100. The microcomputer 103 is realized by, for example, a semiconductor device equipped with an ARM processor. The microcomputer 103 controls, for example, the transmission of radio waves by the transmission antenna 102.

[0055] For example, in the WPT system 1 used in a factory, it is desirable for the receiver 200 to supply power equal to or greater than a predetermined value. Therefore, the microcomputer 103 controls the transmission of radio waves by the transmitting antenna 102 based on a feedback signal transmitted from the receiver 200. The feedback signal relates to, for example, a voltage value at a predetermined location in the receiver 200. Based on the feedback signal, the electric field intensity of the receiver 200 can be grasped in a pseudo manner. When the transmitting antenna 102 has, for example, a plurality of antenna elements, the microcomputer 103 controls the transmitting antenna 102 so that the power feed signal is transmitted from, for example, an optimal antenna element. For example, the microcomputer 103 adjusts the polarization direction of the power feed signal by switching the antenna element to be driven. In addition, the microcomputer 103 adjusts the directivity of the power feed signal by adjusting the drive timing of the antenna element.

[0056] In addition, in the WPT system 1 used indoors such as in a building, the microcomputer 103 controls the transmission of radio waves by the transmitting antenna 102 based on a feedback signal transmitted from the receiver 200. When the transmitting antenna 102 is, for example, a single antenna element, the microcomputer 103 optimizes the power transmission output from the transmitting antenna 102, for example.

[0057] The data transceiver 104 performs processes such as converting digital data to analog data, modulating analog data, etc. The data transceiver 104 also performs processes such as demodulating a signal extracted from a data signal received by the data transceiver antenna 105, and digitizing the demodulated analog data. For example, the data transceiver 104 extracts a feedback signal from the data signal received by the data transceiver antenna 105, converts it into digital data, and transmits it to the microcomputer 103.

[0058] The data transmission / reception antenna 105 is formed to be capable of efficiently transmitting and receiving radio waves in the 2.4 GHz band, for example. The data transmission / reception antenna 105 radiates a data signal supplied from the data transceiver 104. In addition, the data transmission / reception antenna 105 receives a data signal transmitted from the receiver 200.

[0059] The receiver 200 includes, for example, a receiving antenna 201, a rectifier circuit 202, a power management unit 203, a charging unit 204, a microcomputer 205, a data transceiver 206, and a data transmitting / receiving antenna 207. The rectifier circuit 202, the power management unit 203, the charging unit 204, the microcomputer 205, and the data transceiver 206 may be mounted on, for example, a PCB or an FPC (flexible printed circuit).

[0060] The receiving antenna 201 is formed so as to be able to efficiently receive radio waves in the 920 MHz band, for example. The receiving antenna 201 receives the power supply signal radiated from the transmitting antenna 102.

[0061] The rectifier circuit 202 rectifies the radio waves received as a power supply signal and converts them into a DC voltage.

[0062] The power management unit 203 manages the DC voltage. For example, the power management unit 203 controls a charging voltage based on the DC voltage. The power management unit 203 charges the charging unit 204 by controlling the charging voltage. In addition, for example, when power equal to or greater than a predetermined capacity is stored in the charging unit 204, the power management unit 203 supplies the DC voltage to a connected member.

[0063] Moreover, the power management unit 203 causes the charging unit 204 to release the power stored therein under the control of the microcomputer 205 .

[0064] The charging unit 204 stores power in response to an instruction from the power management unit 203. In addition, the charging unit 204 discharges the stored power in response to an instruction from the power management unit 203. The detailed configuration of the charging unit 204 will be described later.

[0065] Microcomputer 205 (hereinafter, may be appropriately referred to as MCU (Microcontroller)) controls the operation of receiver 200. Microcomputer 205 is driven by a DC voltage supplied from power management unit 203 or by power stored in charging unit 204. Microcomputer 205 controls power management unit 203 to cause charging unit 204 to release the power stored therein.

[0066] For example, various sensors can be connected to the receiver 200. For example, a heat sensor, a temperature sensor, a light sensor, a humidity sensor, a vibration sensor, and the like are connected to the receiver 200. The sensors connected to the receiver 200 are driven, for example, by a direct current voltage supplied from the power management unit 203 or by power discharged from the charging unit 204. The microcomputer 205 continuously or intermittently monitors the voltage value at a predetermined portion of the receiver 200, the status of the sensor connected to the receiver 200, information detected by the sensor, and the like. The microcomputer 205 transmits the voltage value at a predetermined portion of the receiver 200, the status of the sensor connected to the receiver 200, information detected by the sensor, and the like as digital data to the data transceiver 206.

[0067] The data transceiver 206 performs processes such as converting digital data supplied from the microcomputer 205 into analog data and modulating the analog data. The data transceiver 206 also performs processes such as demodulating the analog data and digitizing the demodulated analog data. The data transceiver 206 is driven by, for example, a DC voltage supplied from the power management unit 203 or power discharged from the charging unit 204.

[0068] The data transmission / reception antenna 207 is formed to be capable of efficiently transmitting and receiving radio waves in the 2.4 GHz band, for example. The data transmission / reception antenna 207 radiates a data signal supplied from the data transceiver 206. In addition, the data transmission / reception antenna 207 receives a data signal transmitted from the transmitter 100. For example, the data transmission / reception antenna 207 is driven by a DC voltage supplied from the power management unit 203 or power discharged from the charging unit 204.

[0069] The transmission format of the data signal transmitted (radiated) from the data transmission / reception antenna 207 is arbitrary. In particular, since the data signal radiated from the data transmission / reception antenna 207 is a radio wave in the 2.4 GHz band, it may be a signal conforming to the Bluetooth (registered trademark) or IEEE 802.11x (that is, so-called wireless LAN) format. In this case, it is preferable that the data transceiver 104 of the transmitter 100 also has a function of analyzing a data signal in a format that matches the format of the data signal transmitted from the receiver 200. Alternatively, the first information processing device 300 may also have such a function.

[0070] <1.3 Receiver circuit configuration> Fig. 3 is a diagram showing an outline of the circuit configuration of receiver 200 shown in Fig. 2. In the following explanation, detailed explanation of the components of receiver 200 explained with reference to Fig. 2 will be omitted. Also, only the main parts of the components of receiver 200 shown in Fig. 2 are shown.

[0071] As shown in Fig. 3, charging section 204 constituting receiver 200 of this embodiment has two capacitors 204a (C1) and 204b (C2) connected in parallel. The capacitances C1 and C2 of capacitors 204a and 204b are selected so that capacitance C1 of capacitor 204a is equal to or smaller than capacitance C2 of capacitor 204b. Here, capacitor 204a corresponds to the above-mentioned "one capacitor," and capacitor 204b corresponds to the above-mentioned "other capacitor."

[0072] The value to which capacitance C1 of capacitor 204a is set may be determined based on how quickly receiver 200 is required to be brought into an operable state, in other words, how long it takes from the start of power reception from transmitter 100 to charge capacitor 204a to a voltage that allows microcomputer 205 and the like to operate stably. In addition, the value to which capacitance C2 of capacitor 204b is set may be determined based on how stable operation of receiver 200 (mainly microcomputer 205 and the like) is ensured even if the power receiving state of receiver 200 becomes unstable.

[0073] As a method for setting the capacitances C1 and C2 of the capacitors 204a and 204b, for example, the capacitor 204b may be made of an electric double layer capacitor and the capacitor 204a may be made of a ceramic capacitor or the like. A ceramic capacitor can be made compact, which is useful for optimizing the area occupied by the board of the charging unit 204. On the other hand, an electric double layer capacitor has a large capacity and is preferable for stabilizing the power supply to a microcomputer or the like. Naturally, there is no particular limitation on the difference in capacitance or the type of the capacitors 204a and 204b, and it may be appropriately determined depending on what kind of operation is expected from the charging unit 204 (how fast charging and stable power supply are expected).

[0074] The charging unit 204 also has a switch 204c interposed in a power supply path from the capacitor 204b to the microcomputer 205, and a field effect transistor (FET) 204d interposed in a ground side path of the capacitor 204b. The switch 204c and the field effect transistor 204d constitute a first current control unit that adjusts the supply current to the capacitor 204b.

[0075] Switch 204c is in the OFF state at the beginning of receiving power from transmitter 100. Power management unit 203 monitors terminal voltage V1 of capacitor 204a, and when terminal voltage V1 reaches a certain value (for example, 2 V), switch 204c is turned ON by an instruction from power management unit 203. The voltage value that turns switch 204c ON does not need to be a voltage sufficient for stable operation of microcomputer 205, and may be a voltage at which microcomputer 205 can start operating.

[0076] The gate terminal of field effect transistor 204d is connected to microcomputer 205, and the charging current supplied to capacitor 204b is controlled by the gate voltage supplied from microcomputer 205. If microcomputer 205 does not have a terminal capable of finely adjusting the voltage value of the gate voltage (for example, if it does not have an analog output terminal), a voltage regulator (not shown) may be provided between microcomputer 205 and field effect transistor 204d, and microcomputer 205 may send a command to this voltage regulator to analog-control the gate voltage of field effect transistor 204d, and the voltage regulator may perform analog control of the gate voltage.

[0077] In this embodiment, the charging current supplied to the capacitor 204b is controlled by the field effect transistor 204d, but the charging current supplied to the capacitor 204b may be controlled by another element, for example, a bipolar transistor. In this case, the microcomputer 205 may control the base current of the bipolar transistor.

[0078] <1.5 Example of operation> An example of the operation of the receiver 200 of this embodiment will be described below with reference to FIGS.

[0079] When the supply of power from the transmitter 100 to the receiver 200 is started, in other words, when the transmitter 100 starts to transmit a wireless power supply signal, which is a substantially continuous wave, to the receiver 200, the receiving antenna 201 of the receiver 200 receives this wireless power supply signal, and the received wireless power supply signal, which is an AC signal, is converted to a DC voltage by the rectifier circuit 202, and a charging voltage for charging the charging unit 204 is supplied to the charging unit 204 by the power management unit 203.

[0080] At this point, switch 204c of charging unit 204 is still in the OFF state, so the output voltage from power management unit 203 is entirely supplied to capacitor 204a, and only capacitor 204a is charged. As shown in Fig. 4, the voltage V1 across capacitor 204a rises. On the other hand, since the output voltage from power management unit 203 is not supplied to capacitor 204b, capacitor 204b is not charged, and the voltage V2 across capacitor 204b remains at zero.

[0081] In this way, immediately after the start of power supply from transmitter 100 to receiver 200, only one of capacitors 204a, 204b constituting charging section 204, is charged. Since capacitance C1 of one capacitor 204a is set to be equal to or smaller than capacitance C2 of other capacitor 204b, capacitor 204a is charged quickly. This state continues until switch 204c is turned ON (i.e., for a predetermined time).

[0082] This allows capacitor 204a to be sufficiently charged in a short time, thereby shortening the time from when wireless power supply from transmitter 100 starts until switch 204c is turned ON. As a result, the time from when wireless power supply from transmitter 100 starts until microcomputer 205 and the like start operating can be shortened.

[0083] Next, when the inter-terminal voltage V1 of the capacitor 204a exceeds a certain value, the power management unit 203 turns on the switch 204c, whereby a charging voltage is supplied to both the capacitors 204a and 204b constituting the charging unit, and both the capacitors 204a and 204b are charged.

[0084] However, when switch 204c is turned ON to start charging either of capacitors 204a, 204b, it is expected that the inter-terminal voltages V1, V2 of capacitors 204a, 204b will temporarily drop, and the voltage supplied to microcontroller 205 will fall below the voltage at which microcontroller 205 can continue to operate.

[0085] Therefore, when the supply of the operating voltage is started by turning on the switch 204c, the microcomputer 205 gradually increases the gate voltage V3 of the field effect transistor 204d as shown in Fig. 4, gradually decreasing the resistance value of the field effect transistor 204d. As a result, the current supplied to the capacitor 204b is gradually increased, and the capacitor 204b is gradually charged.

[0086] Thereafter, when the gate voltage of the field effect transistor 204d rises to a certain value (1.8 V in FIGS. 3 and 4), the resistance value of the field effect transistor 204d becomes minimum, and the combined voltage value V1+V2 of the inter-terminal voltages V1 and V2 of the capacitors 204a and 204b rises.

[0087] As a result, both capacitors 204a and 204b are sufficiently charged, so that even if the wireless power supply signal from transmitter 100 is temporarily interrupted (for example, because a person is present between transmitter 100 and receiver 200) and the power supply state of receiver 200 deteriorates, since capacitor 204b, which has a larger capacity, is sufficiently charged, the operation of microcontroller 205 and the like can be continued by power supply from capacitor 204b until the power supply state is restored.

[0088] <1.6 Effects of the first embodiment> As described above in detail, according to the WPT system 1 of the present embodiment, in the receiver 200 to which power is supplied wirelessly, it is possible to ensure both rapid operation of the receiver 200 and stable continuation of the operation.

[0089] <2. Second embodiment> In the WPT system 1 of the first embodiment described above, the charging voltage supply to the other capacitor 204b is performed after a predetermined time has elapsed since the start of wireless power supply from the transmitter 100 by turning on the switch 204c, thereby quickly charging the one capacitor 204a. In the WPT system 1 according to the second embodiment, the current supplied to the other capacitor is made smaller than the current supplied to the one capacitor, so that the time required for charging the one capacitor to be completed is shorter than the time required for charging the other capacitor.

[0090] <2.1 Receiver circuit configuration> FIG. 5 is a circuit diagram showing the configuration of the charging unit 204 of the receiver 200 in the WPT system 1 of the second embodiment.

[0091] The charging section 204 according to the second embodiment shown in Fig. 5 has three capacitors 204e (C3), 204f (C1), and 204g (C2) connected in parallel. The capacitances C1, C2, and C3 of the capacitors 204e to 204g are selected so that the capacitance C3 of the capacitor 204e is equal to or smaller than the capacitance C1 of the capacitor 204f and the capacitance C2 of the capacitor 204g. Here, the capacitor 204e corresponds to the above-mentioned "one capacitor," and the capacitors 204f and 204g correspond to the above-mentioned "other capacitors."

[0092] As a method for setting the capacitances C1, C2, and C3 of the capacitors 204e to 204g, for example, the capacitors 204f and 204g are configured as electric double layer capacitors, and the capacitor 204e is configured as a ceramic capacitor or the like, as in the first embodiment. In the charging unit 204 of this embodiment, the capacitance C1 of the capacitor 204e and the capacitance C2 of the capacitor 204g are set to the same capacitance, but a relationship in magnitude may be established between these capacitances C1 and C2. It is sufficient that the capacitances C1 and C2 are at least larger than the capacitance C3 of the capacitor 204e.

[0093] A Zener diode 204h and a resistor 204i are connected in parallel and interposed in the charging power supply path of the capacitors 204e and 204f.

[0094] The Zener diode 204h is connected in a so-called reverse direction. That is, the cathode of the Zener diode 204h is connected to the capacitor 204e side, and the anode is connected to the capacitor 204f side. This Zener diode 204h limits the charging power supplied to the capacitors 204f, 204g to via the resistor 204i until the charging voltage supplied to the capacitors 204f, 204g reaches a certain value, that is, until it reaches the breakdown voltage. Therefore, the breakdown voltage of the Zener diode 204h is set to a voltage value (e.g., 2V) that is a condition for turning on the switch 204c in the first embodiment, or a value slightly lower than this voltage value.

[0095] Resistor 204i is provided to make the charging current to capacitors 204f, 204g smaller than the charging current to capacitor 204e until the charging voltage supplied to capacitors 204f, 204g reaches a certain value. Therefore, resistance value R1 of resistor 204i is set from the viewpoint of how much time it takes to complete charging of capacitors 204f, 204g from the start of wireless power supply from transmitter 100.

[0096] The Zener diode 204h and resistor 204i constitute a second current control section and current limiting element that makes the current supplied to the capacitors 204f, 204g smaller than the current supplied to the capacitor 204e until the charging voltage supplied to the capacitors 204f, 204g reaches a constant value.

[0097] In this embodiment, the Zener diode 204h and the resistor 2041 are used as the second current control section and the current limiting element, but there are no particular limitations and any known configuration can be suitably applied as long as the circuit configuration makes the charging current of the capacitors 204f and 204g smaller than the charging current of the capacitor 204e during the period from the start of reception of the transmission power from the transmitter 100 until a predetermined time. As an example, a Schottky (barrier) diode can be used instead of the Zener diode 204h.

[0098] <2.2 Example of operation> An example of the operation of the receiver 200 of this embodiment will be described below with reference to FIG.

[0099] As in the first embodiment, when wireless power supply from the transmitter 100 starts, a DC voltage from the power management unit 203 is supplied to the capacitor 204e, and charging of the capacitor 204e starts. At this point, the DC voltage from the power management unit 203 is used as a charging voltage for the capacitor 204e, and the voltage to the Zener diode 204h does not exceed the breakdown voltage, so that charging power is supplied to the capacitors 204f and 204g only via the resistor 204i. The current value of this charging power is a current according to the resistance value R1 of the resistor 204i, and is smaller than the current value of the charging power to the capacitor 204e. Therefore, the charging of the capacitors 204f and 204g proceeds more slowly than the charging of the capacitor 204e.

[0100] Thereafter, as the charging of capacitor 204e progresses (i.e., after a predetermined time has passed), the voltage to Zener diode 204h exceeds the breakdown voltage, and charging power is supplied to capacitors 204f and 204g via a path via Zener diode 204h as well as a path via resistor 204i. At this point, since the charging of capacitor 204e has already progressed considerably, the charging power supplied from power management unit 203 is mainly used to charge capacitors 204f and 204g.

[0101] This allows capacitor 204e to be sufficiently charged in a short time, thereby shortening the time from the start of wireless power supply from transmitter 100 until the voltage to Zener diode 204h exceeds the breakdown voltage. As a result, the time from the start of wireless power supply from transmitter 100 until the start of operation of microcontroller 205 and the like can be shortened.

[0102] Furthermore, when the voltage to the Zener diode 204h exceeds the breakdown voltage, charging power is supplied to all of the capacitors 204e to 204g, so even if the wireless power supply signal from the transmitter 100 is temporarily interrupted (for example, because a person is present between the transmitter 100 and the receiver 200) and the power supply state of the receiver 200 deteriorates, the capacitors 204f and 204g, which have large capacitance, are sufficiently charged, so that the operation of the microcomputer 205 and the like can be continued by power supply from the capacitors 204f and 204g until the power supply state is restored. Moreover, even when the voltage to the Zener diode 204h does not exceed the breakdown voltage, charging power is supplied to the capacitors 204f and 204g via the resistor 204i, so that the capacitors 204f and 204g can be charged even when the voltage to the Zener diode 204h does not exceed the breakdown voltage, and as a result, the time required to sufficiently charge the capacitors 204f and 204g can be shortened.

[0103] <2.3 Effects of the second embodiment> As described in detail above, according to the WPT system 1 of this embodiment, similar to the WPT system 1 of the first embodiment, in the receiver 200 that is wirelessly powered, it is possible to achieve both rapid operation of the receiver 200 and stable continuation of operation.

[0104] <3 Notes> In addition, the above-described embodiments are described in detail to clearly explain the present disclosure, and are not necessarily limited to those including all of the described configurations. In addition, some of the configurations of each embodiment can be added to, deleted from, or replaced with other configurations.

[0105] In addition, the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. The present invention can also be realized by software program code that realizes the functions of the embodiments. In this case, a storage medium on which the program code is recorded is provided to a computer, and a processor included in the computer reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-mentioned embodiments, and the program code itself and the storage medium storing it constitute the present invention. Examples of storage media for supplying such program code include flexible disks, CD-ROMs, DVD-ROMs, hard disks, SSDs, optical disks, magneto-optical disks, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, etc.

[0106] Furthermore, the program code for realizing the functions described in this embodiment can be implemented in a wide range of program or script languages, such as assembler, C / C++, perl, Shell, PHP, Java (registered trademark), and the like.

[0107] Furthermore, the program code of the software that realizes the functions of the embodiments may be distributed over a network and stored in a storage means such as a computer's hard disk or memory, or in a storage medium such as a CD-RW or CD-R, and the processor of the computer may read out and execute the program code stored in the storage means or storage medium.

[0108] The matters described in the above embodiments will be supplemented below.

[0109] (Appendix 1) The receiver (200) wirelessly receives transmission power consisting of an AC signal, the receiver (200) having a rectifier unit (202) that rectifies the transmission power, a power management unit (203) that manages the rectified voltage from the rectifier unit (202), a charging unit (204) that is charged by the output voltage from the power management unit (203), and a control unit that operates by power supplied from the charging unit (204) and controls the entire receiver (200), the charging unit (204) having a plurality of capacitors (204a, 204b), and charging one of the plurality of capacitors (204a, 204b), for a predetermined time from the start of reception of the transmission power, and charging the other capacitors (204b) other than the one capacitor (204a) after the predetermined time. (Appendix 2) 2. The receiver (200) of claim 1, wherein the capacitance of one capacitor (204a) is equal to or smaller than the capacitance of the other capacitor (204b). (Appendix 3) A receiver (200) as described in Appendix 2, wherein the charging unit (204) has a first current control unit (204c, 204d) that adjusts the current supplied to the other capacitor (204b), and the first current control unit (204c, 204d) adjusts the current supplied to the other capacitor (204b) to charge one capacitor (204a) for a predetermined time from the start of reception of transmission power, and also charges the other capacitor (204b) after the predetermined time. (Appendix 4) The receiver (200) described in Appendix 3, wherein the first current control section (204c, 204d) is a field effect transistor (204d), and the current supplied to the other capacitor (204b) is controlled by controlling the current between the source and drain of this field effect transistor (204d). (Appendix 5) The receiver (200) according to claim 4, wherein the control unit (205) controls a gate voltage of the field effect transistor (204d) to control a source-drain current of the field effect transistor (204d). (Appendix 6) The receiver (200) according to claim 5, wherein the control unit (205) monitors the charging voltage to the other capacitor (204b) and controls the source-drain current of the field effect transistor (204d) based on the charging voltage. (Appendix 7) The receiver (200) wirelessly receives transmission power consisting of an AC signal, the receiver (200) having a rectifier unit (202) that rectifies the transmission power, a power management unit (203) that manages a rectified voltage from the rectifier unit (202), a charging unit (204) that is charged by an output voltage from the power management unit (203), and a control unit (205) that operates by power supplied from the charging unit (204) and controls the entire receiver (200), the charging unit (204) having a plurality of capacitors (204e to 204g), and the charging unit (204) having a second current control unit (204h, 204i) that makes the charging current of other capacitors (204f, 204g) of the plurality of capacitors (204e to 204g) smaller than the charging current of one capacitor (204e) during a predetermined time from the start of reception of the transmission power. (Appendix 8) A receiver (200) according to appendix 8, wherein the second current control unit (204h, 204i) is a current limiting element (204h, 204i) interposed between one capacitor (204e) and another capacitor (204f, 204g) in a charging power supply path to the plurality of capacitors (204e to 204g). (Appendix 9) 9. The receiver (200) of claim 8, wherein the capacitance of one capacitor (204e) is equal to or smaller than the capacitances of the other capacitors (204f, 204g). (Appendix 10) A wireless power supply system (1) including a transmitter (100) that wirelessly transmits transmission power consisting of an AC signal, and a receiver (200) that wirelessly receives the transmission power, the receiver (200) having a rectifier unit (202) that rectifies the transmission power, a power management unit (203) that manages a rectified voltage from the rectifier unit (202), a charging unit (204) that is charged by an output voltage from the power management unit (203), and a control unit that operates by power supplied from the charging unit (204) and controls the entire receiver (200), wherein the charging unit (204) has a plurality of capacitors (204a, 204b), and charges one capacitor (204a) of the plurality of capacitors (204a, 204b) for a predetermined time from a start of reception of the transmission power, and after the predetermined time, also charges the other capacitors (204b) other than the one capacitor (204a). (Appendix 11) The present invention relates to a transmitter (100) that wirelessly transmits transmission power consisting of an AC signal, and a receiver (200) that wirelessly receives the transmission power, the receiver (200) having a rectifier unit (202) that rectifies the transmission power, a power management unit (203) that manages the rectified voltage from the rectifier unit (202), a charging unit (204) that is charged by the output voltage from the power management unit (203), and a control unit (205) that operates by power supplied from the charging unit (204) and controls the entire receiver (200). The charging unit (204) has a plurality of capacitors (204e to 204g), and the charging unit (204) has a second current control unit (204h, 204i) that makes the charging current of other capacitors (204f, 204g) of the plurality of capacitors (204e to 204g) smaller than the charging current of one capacitor (204e) during a period from the start of reception of transmission power until a predetermined time. [Explanation of symbols]

[0110] 1...WPT system 100...transmitter 200...receiver 201...receiving antenna 202...rectifier circuit 203...power management unit 204...charging unit 204a, 204b, 204e, 204f, 204g...capacitor 204c...switch 204d...field effect transistor 204h...zener diode 204i...resistor 205...microcomputer 206...data transceiver 207...data transceiver antenna 300...first information processing device 400...second information processing device

Claims

[Claim 1] A receiver that wirelessly receives transmitted power consisting of AC signals, The receiver comprises a rectifier unit that rectifies the transmitted power, a power management unit that manages the rectified voltage from the rectifier unit, a charging unit that is charged by the output voltage from the power management unit, and a control unit that operates using the power supplied from the charging unit and controls the entire receiver. The charging unit has multiple capacitors, and charges one of the multiple capacitors for a predetermined time from the start of receiving the transmitted power, and after the predetermined time, it also charges the other capacitors besides the one mentioned above. Receiver.

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