JP2016067075A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to control the output destination of power supplied by a power supply apparatus so that communication is normally performed and charging to a battery is normally performed.SOLUTION: An electronic apparatus according to the present invention includes: an antenna for receiving electric power by radio; a power control unit for storing or distributing power by inputting therein the power received by the antenna; a communication unit for communicating with an external apparatus via the antenna; a switching unit for switching a path from the antenna to the power control unit or the communication unit; and a drive unit driven by the power received by the antenna and driving the switching unit. The input impedance of the drive unit viewed from the antenna is higher than the input impedance of either the power control unit side or the communication unit side viewed from the antenna.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electronic device that receives power wirelessly, and more particularly to driving a switch used for switching between power feeding and communication.

  In recent years, a power supply device having a primary coil as an antenna for outputting power wirelessly without being physically connected by a connector, and a secondary coil for receiving power supplied from the power supply device wirelessly as an antenna A wireless power feeding system including an electronic device is known. There is also known a wireless power feeding system that uses the antenna to perform communication in addition to wireless power feeding.

  In such an electronic device, wireless communication for notifying the power supply device of the state of the electronic device and power reception from the power supply device are alternately performed using one antenna (Patent Document 1).

JP 2013-38854 A

  The electronic device as described above supplies power for communication supplied from the power supply device to the communication unit during the communication period and receives power for charging the battery from the power supply device from the power supply device. The battery was charged using the supplied power.

  However, electric power for charging the battery from the power supply device is supplied to the communication unit of the electronic device, and excessive power may be supplied to the communication unit. In such a case, the communication unit of the electronic device may not be able to perform normal communication, and it is necessary to prevent excessive power from being supplied to the communication unit of the electronic device. In addition, the battery is supplied with power for communication from the power supply device, and the power supplied from the power supply device may be insufficient as power for charging the battery.

  Therefore, an object of the present invention is to enable control of an output destination of power supplied from a power supply device so that communication is normally performed and charging of a battery is normally performed.

  In order to achieve the above object, an electronic device of the present invention communicates with an external device via an antenna that receives power wirelessly, a power control unit that inputs and stores or distributes the power received by the antenna, and the antenna. A communication unit that performs switching, a switching unit that switches a path from the antenna to the power control unit and the communication unit, and a driving unit that operates with the power received by the antenna and drives the switching unit. The input impedance is higher than the input impedance on either the power control unit side or the communication unit side viewed from the antenna.

  ADVANTAGE OF THE INVENTION According to this invention, the output destination of the electric power supplied from an electric power feeding apparatus can be controlled so that communication can be performed normally and charge of a battery can be performed normally.

The figure which showed an example of the structure of the system in Example 1 and 2 The block diagram which showed an example of the structure of the system in Example 1 and 2 The block diagram which showed an example of the structure of the power receiving part in Example 1 and 2 The block diagram which showed an example of the structure of the electric power control part in Example 1 and 2 The block diagram which showed an example of the structure of the switch drive part in Example 1. The figure which showed an example of the resonant circuit in Example 1 and 6 Voltage waveforms in Examples 1 and 2 The block diagram which showed an example of the structure of the switch drive part in Example 2.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments, and various modifications and changes can be made within the scope of the gist.

Example 1
(Description of system configuration)
Hereinafter, Example 1 will be described in detail with reference to the drawings. As illustrated in FIG. 1, the system according to the first embodiment includes an electronic device 200 and a power supply device 100 that supplies power to the electronic device 200 wirelessly. The power supply device 100 can perform wireless communication with the electronic device 200 for controlling power supply to the electronic device.

  When the distance between the power supply device 100 and the electronic device 200 is within a predetermined range, the power supply device 100 having the power supply antenna 101 performs wireless communication via the power supply antenna 101 and is the device that can receive power from the electronic device 200? Judge whether or not. When the power supply device 100 determines that the electronic device 200 is a device that can receive power, the power supply device 100 outputs power for power supply via the power supply antenna 101 to supply power to the electronic device 200.

  Electronic device 200 having power receiving antenna 201 wirelessly receives power output from power feeding device 100 through power receiving antenna 201.

  When the distance between the power supply device 100 and the electronic device 200 is within a predetermined range, the power supply device 100 distributes a weak power at regular intervals in order to detect whether or not the electronic device 200 is within the predetermined range. To output.

  Note that the predetermined range is a range in which the electronic device 200 can perform communication using power for communication supplied from the power supply device 100.

  The electronic device 200 may be an imaging device such as a digital still camera or a digital video camera as long as it is an electronic device that operates with power supplied from the secondary battery 404, and a player that reproduces audio data and video data. Such a playback device may be used. The electronic device 200 may be a mobile phone or a smartphone, and the electronic device 200 may be a mobile device such as a car. Further, the electronic device 200 may be a mouse or a speaker that operates with only the received power without a secondary battery.

(Configuration of power supply device 100)
FIG. 2 is a block diagram illustrating an example of the configuration of a system including the power supply device 100 and the electronic device 200.

  As illustrated in FIG. 2, the power feeding device 100 outputs AC power generated inside the power feeding device 100 to the power receiving antenna 201 of the electronic device 200 via the power feeding antenna 101.

  The power generated by the power supply device 100 includes first power and second power. The first power is power for communication for the power supply device 100 to transmit a command for controlling the electronic device 200 to the electronic device 200. The second power is higher than the first power and is necessary for causing the electronic device 200 to charge the secondary battery 404 and causing the electronic device 200 to operate the camera system 205. For example, the first power is 1 W or less, and the second power is 1 W to 10 W.

  In addition, the power supply device 100 transmits a command to the electronic device 200 via the power supply antenna 101, and a response corresponding to the command transmitted to the electronic device 200 via the power supply antenna 101 and a command transmitted from the electronic device 200. To receive.

  Note that when the power supply device 100 supplies the first power to the electronic device 200, the power supply device 100 can transmit a command to the electronic device 200. However, when the power supply device 100 supplies the second power to the electronic device 200, the power supply device 100 cannot transmit a command to the electronic device 200.

  The first power is power set so that the power supply device 100 can transmit a command to any device other than the electronic device 200.

  The command transmitted by the power supply apparatus 100 is a command conforming to a predetermined communication protocol. The predetermined communication protocol is a communication protocol compliant with ISO / IEC 18092 standard such as RFID (Radio Frequency IDentification). Further, the predetermined communication protocol may be a communication protocol that conforms to the NFC (Near Field Communication) standard. The command transmitted by the power supply device 100 is transmitted to the electronic device 200 while being superimposed on the first power.

  The pulse signal transmitted to the electronic device 200 is detected by the electronic device 200 as bit data including “1” information and “0” information. The command includes identification information for identifying a destination, a command code indicating an operation instructed by the command, and the like. Note that the power supply device 100 can also transmit the command only to the electronic device 200 by changing the identification information included in the command. The power supply device 100 can also transmit the command to the electronic device 200 and devices other than the electronic device 200 by changing the identification information included in the command.

  The power output from the power feeding antenna 101 is AC power. The power supply device 100 resonates at a frequency f of power output from the power supply antenna 101.

  The resonance frequency f is set based on parasitic factors of the power supply antenna 101, a resonance circuit (not shown) inside the power supply device 100, a casing of the power supply device 100, and an external circuit.

  Equation 1 below is an equation showing the relationship among the resonance frequency f, the inductance L, and the capacitance C. L in Equation 1 is an inductance value due to parasitic factors external to the power feeding antenna 101, and C in Equation 1 is a resonance circuit inside the power feeding device 100 and a capacitance value due to parasitic factors.

  In the first and second embodiments, the following description will be made assuming that the resonance frequency f is 13.56 MHz.

(Configuration of electronic device 200)
Next, an example of the configuration of the electronic device 200 will be described with reference to FIG. The configuration shown in FIG. 2B will be described in the second embodiment.

  A digital still camera is taken as an example of the electronic device 200, and the following description will be given.

  The electronic device 200 includes a power receiving antenna 201, a power receiving unit 202, a power control unit 203, a control unit 204, a camera system unit 205, a communication unit 206, and a switch driving unit 207.

  The power receiving antenna 201 is an antenna for receiving power supplied from the power supply apparatus 100. The electronic device 200 receives power from the power supply device 100 or receives a command via the power receiving antenna 201. The electronic device 200 transmits a command for controlling the power supply device 100 and a response corresponding to the command received from the power supply device 100 via the power receiving antenna 201.

  The power receiving unit 202 supplies the power received by the power receiving antenna 201 to any one of the power control unit 203 and the communication unit 206. The power receiving unit 202 switches the connection destination of the power receiving antenna 201 between the power control unit 203 and the communication unit 206 in accordance with an instruction from the control unit 204. The resonance frequency of the electronic device 200 matches the resonance frequency f of the power supply device 100. The power receiving unit 202 will be described later with reference to FIG.

  When the power reception antenna 202 is connected to the power control unit 203 by the power reception unit 202, the power received by the power reception antenna 201 is supplied via the power reception unit 202. Further, the power control unit 203 charges the secondary battery 404 using the power supplied via the power receiving unit 202. Further, the power control unit 203 supplies power to the camera system 205 using the power supplied via the power receiving unit 202. The power control unit 203 will be described later with reference to FIG.

  The control unit 204 controls each unit of the electronic device 200.

  The control unit 204 is a CPU that operates with low power consumption. The control unit 204 operates using, for example, several mW of power. The control unit 204 may operate using the power supplied from the secondary battery 404 or may operate using the power received by the power receiving antenna 201.

  For example, the control unit 204 may operate using part of the power supplied from the power receiving antenna 201 to the communication unit 206. Further, for example, the control unit 204 exchanges data from the camera system unit 205 and transmits the data acquired from the camera system unit 205 to the power supply apparatus 100 using the communication unit 206. Furthermore, the control unit 204 accesses, for example, a register of the communication unit 206 to check whether the communication unit 206 has started communication or to check the communication state of the communication unit 206.

  The camera system unit 205 includes an imaging unit for generating image data from an optical image of a subject, a recording unit for storing image data generated by the imaging unit, and a reproduction unit for reproducing the image data.

  The communication unit 206 performs wireless communication with the power supply device 100 via the power receiving antenna 201. The command received by the communication unit 206 is a command conforming to the above-described predetermined communication protocol. The command transmitted by the communication unit 206 is a command that conforms to the above-described predetermined communication protocol. The response transmitted by the communication unit 206 is a command that conforms to the above-described predetermined communication protocol.

  The communication unit 206 can also communicate with a device that conforms to the same communication protocol as the communication protocol supported by the power supply device 100.

  Electronic device 200 has a power supply mode and a communication mode as operation modes. When the electronic device 200 is in the communication mode, the electronic device 200 causes the communication unit 206 to perform wireless communication using the power output from the power supply device 100. When the electronic device 200 is in the power supply mode, the electronic device 200 causes the charge control unit 403 to charge the secondary battery 404 using the power output from the power supply device 100. Furthermore, when the electronic device 200 is in the power supply mode, the electronic device 200 may operate the camera system 205 using the power output from the power supply device 100.

  The switch drive unit 207 generates a signal for controlling a later-described switch unit 302 and switch unit 303 included in the power receiving unit 202, and outputs the signal to the switch unit 302 and switch unit 303. The switch unit 302 and the switch unit 303 are used to switch the connection destination of the power receiving antenna 201 between the communication unit 206 and the power control unit 203. The switch driving unit 207 will be described later with reference to FIG.

(Configuration of power receiving unit 202)
Next, the power receiving unit 202 will be described with reference to FIG. FIG. 3 is a block diagram illustrating an example of the configuration of the power receiving unit 202.

  The power reception unit 202 includes a resonance element 301 a, a resonance element 301 b, a switch unit 302, and a switch unit 303. Furthermore, the power receiving unit 202 includes a compensating resonant element 304a and a compensating resonant element 304b. The switch unit 302 is installed in the vicinity of the power control unit 203, and the switch unit 303 is installed in the vicinity of the communication unit 206.

  The switch unit 302 and the switch unit 303 include, for example, one or more field effect transistors (FETs). Further, the switch unit 302 and the switch unit 303 may be configured by relay switches other than FETs.

  The switch unit 302 and the switch unit 303 are used to set the connection destination of the power receiving antenna 201 to the power control unit 203 or the communication unit 206. The switch unit 302 and the switch unit 303 are used to switch the connection between the power receiving antenna 201 and the resonant element 301a and the resonant element 301b. The switch unit 302 and the switch unit 303 are used to switch the connection between the power receiving antenna 201 and the compensating resonant element 304a and compensating resonant element 304b. When the switch unit 302 and the switch unit 303 are on, the resonance element 301a, the resonance element 301b, the compensation resonance element 304a, and the compensation resonance element 304b are connected in parallel to the power receiving antenna 201. When the switch unit 302 and the switch unit 303 are off, the resonant element 301 a and the resonant element 301 b are connected in series to the power receiving antenna 201.

  The resonant element 301a, the resonant element 301b, the compensating resonant element 304a, and the compensating resonant element 304b are used for the power receiving antenna 201 of the electronic device 200 to resonate with the power feeding device 100.

  When the power receiving antenna 201 is a coil, the resonance element 301a and the resonance element 301b are capacitors. Therefore, in the first embodiment, the resonance element 301a and the resonance element 301b are described below as capacitors. The power receiving unit 202 may further include a coil in addition to the resonance element 301a and the resonance element 301b.

  Similarly, the compensated resonant element 304a and the compensated resonant element 304b will be described below assuming that they are capacitors. Further, the power receiving unit 202 may further include a coil in addition to the compensating resonant element 304a and the compensating resonant element 304b.

  FIG. 3 shows a configuration in which the capacitance value of the resonance circuit when the electronic device 200 is in the communication mode is smaller than the capacitance value of the resonance circuit when the electronic device 200 is in the power supply mode. The compensating resonant element 304a is a capacitor having a capacitance value smaller than the capacitance value of the resonant element 301a, and a capacitor having a capacitance value smaller than the capacitance value of the resonant element 301b. The compensating resonant element 304b is a capacitor having a capacitance value smaller than the capacitance value of the resonant element 301a, and a capacitor having a capacitance value smaller than the capacitance value of the resonant element 301b.

  The switch unit 302 and the switch unit 303 are connected to, for example, the switch drive unit 207 and are controlled by the switch drive unit 207.

  The switch unit 302 is connected between the power control unit 203 and the resonant element 301a and the resonant element 301b. The switch unit 302 is connected to the input terminal of the power control unit 203. When the switch unit 302 is turned on by the switch driving unit 207, the switch unit 302 short-circuits the power control unit 203. For this reason, when the switch unit 302 is on, the power received by the power receiving antenna 201 is not supplied to the power control unit 203. When the switch unit 302 is turned off by the switch driving unit 207, the power receiving antenna 201 and the power control unit 203 are connected. When the switch unit 302 is off, the power received by the power receiving antenna 201 is supplied to the power control unit 203. The input impedance of the power control unit 203 needs to be higher than that of a line in which the compensating resonant element 304a, the compensating resonant element 304b, and the switch unit 302 are connected in series. A method for making the input impedance of the power control unit 203 higher than the line in which the compensating resonant element 304a, the compensating resonant element 304b, and the switch unit 302 are connected in series will be described later with reference to FIG.

  The switch unit 303 is connected between the communication unit 206 and the power receiving antenna 201. When the switch unit 303 is turned on by the switch driving unit 207, the communication unit 206 and the power receiving antenna 201 are connected. For this reason, when the switch unit 303 is on, the power received by the power receiving antenna 201 is supplied to the communication unit 206. When the switch unit 303 is turned off by the switch driving unit 207, the connection between the communication unit 206 and the power receiving antenna 201 is disconnected. For this reason, when the switch unit 303 is off, the power received by the power receiving antenna 201 is not supplied to the communication unit 206.

  When the electronic device 200 is in the power supply mode, the switch drive unit 207 turns off the switch unit 302 and the switch unit 303. When the electronic device 200 is in the communication mode, the switch drive unit 207 turns on the switch unit 302 and the switch unit 303.

  The switch drive unit 207 turns off the switch unit 302 and the switch unit 303 when the second power is output from the power supply apparatus 100. In this case, the switch driving unit 207 controls the switch unit 302 and the switch unit 303 so as to supply the power received by the power receiving antenna 201 to the power control unit 203.

  The switch drive unit 207 turns on the switch unit 302 and the switch unit 303 when the first power is output from the power supply apparatus 100. In this case, the switch driving unit 207 controls the switch unit 302 and the switch unit 303 so as to supply the power received by the power receiving antenna 201 to the communication unit 206. The switch driving unit 207 determines whether the first power is output from the power supply device 100 or the second power is output from the power supply device 100, and the switch unit 302 and the switch unit 303 are determined according to the determination result. To control. The switch driving unit 207 determines whether the electronic device 200 is in the communication mode or the electronic device 200 is in the power supply mode, and controls the switch unit 302 and the switch unit 303 according to the determination result.

  FIG. 6 is a diagram illustrating an example of a relationship among the power receiving antenna, the power control unit, and the communication unit when the electronic device 200 includes the power receiving unit 202 in FIG. 3.

  6A illustrates the power receiving antenna 201, the power control unit 203, the communication unit 206, and the switch unit 302 and the switch unit 303 that are turned on by the switch driving unit 207 (when the electronic device 200 is in the communication mode). It is the figure which showed an example of this relationship. When the switch unit 302 and the switch unit 303 are turned on by the switch driving unit 207, the resonant element 301a and the resonant element 302b, and the compensating resonant element 304a and the compensating resonant element 304b are in series as shown in FIG. Connected to. When the switch unit 302 and the switch unit 303 are turned on by the switch driving unit 207, the resonance element 301a, the resonance element 302b, the compensation resonance element 304a, and the compensation are made with respect to the power receiving antenna 201 as shown in FIG. The resonant elements 304b are connected in parallel. Thus, the resonant element 301a, the resonant element 301b, the compensating resonant element 304a, and the compensating resonant element 304b constitute a parallel resonant circuit for the power receiving antenna 201. In this case, the power control unit 203 causes the switch unit 302 to short-circuit the input line of the power control unit 203. For this reason, in FIG. 6A, since it is the same as that the power control unit 203 is not connected, the power control unit 203, the connection between the power control unit 203 and the compensating resonant element 304a, and the power control unit 203 The connection with the compensating resonant element 304b is indicated by a dotted line.

  As shown in FIG. 6A, when the electronic device 200 is in the communication mode, the switch drive unit 207 controls the switch unit 302 and the switch unit 303 to be turned on. Thereby, when the electronic device 200 is in the communication mode, the power received by the power receiving antenna 201 is not supplied to the power control unit 203. Note that the power received by the power receiving antenna 201 is supplied to the communication unit 206.

  FIG. 6B illustrates the power receiving antenna 201, the power control unit 203, the communication unit 206, and the switch unit 302 and the switch unit 303 that are turned off by the switch driving unit 207 (when the electronic device 200 is in the power feeding mode). It is the figure which showed an example of this relationship. When the switch unit 302 and the switch unit 303 are turned off by the switch driving unit 207, as shown in FIG. 6B, the resonant element 301a and the resonant element 302b, and the compensating resonant element 304a and the compensating resonant element 304b are in series. Not connected to. When the switch unit 302 and the switch unit 303 are turned off by the switch driving unit 207, the resonant element 301a and the resonant element 302b are connected in series to the power receiving antenna 201 as shown in FIG. However, the compensating resonant element 304 a and the compensating resonant element 304 b are not connected to the power receiving antenna 201.

  In this case, the input of the communication unit 206 is opened by the switch unit 303 in the communication unit 206. For this reason, in FIG. 6B, since the communication unit 206 is not connected, the communication unit 206 and the connection between the communication unit 206 and the switch unit 303 are indicated by dotted lines. Further, since the switch unit 302 is also turned off, the connection between the switch unit 302 and the compensated resonant element 304a and the connection between the switch unit 302 and the compensated resonant element 304b are indicated by dotted lines.

  As shown in FIG. 6B, when the electronic device 200 is in the power supply mode, the switch drive unit 207 controls the switch unit 302 and the switch unit 303 to be turned off. In this case, since the switch unit 303 is opened, when the electronic device 200 is in the power supply mode, the power received by the power receiving antenna 201 is supplied to the power control unit 203. However, the power received by the power receiving antenna 201 is not supplied to the communication unit 206. In this case, the power receiving antenna 201 and the resonant element 301a are connected in series, and the power receiving antenna 201 and the resonant element 301b are connected in series. Accordingly, the resonant element 301a and the resonant element 301b constitute a series resonant circuit for the power receiving antenna 201.

  As described above, the electronic device 200 includes the power receiving unit 202 as illustrated in FIG. 3, thereby using the switch driving unit 207 when the electronic device 200 is in the communication mode, when the electronic device 200 is in the power supply mode, and the switch driving unit 207. Thus, the connection destination of the power receiving antenna 201 can be switched. The switch driving unit 207 can switch the connection between the power receiving antenna 201 and the resonant element 301a, the resonant element 301b, the compensated resonant element 304a, and the compensated resonant element 304b by controlling the switch unit 302 and the switch unit 303. Thereby, the switch drive unit 207 can control whether to connect a series resonant circuit to the power receiving antenna 201 or to connect a parallel resonant circuit to the power receiving antenna 201. When communication is performed by the electronic device 200, a parallel resonant circuit is suitable because the load on the electronic device 200 is small (load impedance is large). Therefore, the switch drive unit 207 controls the switch unit 302 and the switch unit 303 so that the parallel resonant circuit is connected to the power receiving antenna 201 when the electronic device 200 is in the communication mode. Therefore, the electronic device 200 can increase the communication sensitivity of the communication unit 206 when the electronic device 200 is in the communication mode. In addition, when power is received from the power supply device 100 by the electronic device 200, a series resonant circuit is suitable because the load on the electronic device 200 is large (load impedance is small). Therefore, the switch drive unit 207 controls the switch unit 302 and the switch unit 303 so that the series resonance circuit is connected to the power receiving antenna 201 when the electronic device 200 is in the power supply mode. Therefore, when the electronic device 200 is in the power supply mode, the electronic device 200 can reduce a loss of power supplied from the power supply device 100 and can increase power supply efficiency.

(Configuration of power control unit 203)
Next, the power control unit 203 will be described with reference to FIG. FIG. 4 is a block diagram illustrating an example of the configuration of the power control unit 203.

  The power control unit 203 includes a rectification unit 401, a smoothing capacitor 402, a charge control unit 403, a secondary battery 404, and a switch 405.

  AC power received by the power receiving antenna 201 is supplied from the power receiving unit 202 to the power control unit 203. As shown in FIG. 4, the DC switch 405 is installed between the rectifying unit 401 and the smoothing capacitor 402. Further, the switch driving unit 207 applies a DC bias voltage between the rectifying unit 401 and the smoothing capacitor 402.

  The DC bias voltage may be applied between the rectifying unit 401 and the smoothing capacitor 402 via a resistor (for example, 1 KΩ) from the switch driving unit 207. The value of the DC bias voltage applied by the switch driving unit 207 is a voltage value higher than the peak value of the AC voltage before being input to the rectifying unit 401.

  The rectifying unit 401 includes a diode and the like. The rectifying unit 401 is, for example, a full wave rectifying circuit using four diodes. Further, the rectifier 401 may be a half-wave rectifier circuit using one diode. The rectifying unit 401 smoothes the AC power supplied from the power receiving unit 202 using the smoothing capacitor 402 and converts it into DC power.

  The smoothing capacitor 402 includes, for example, an electric field capacitor or a ceramic capacitor. The capacitance of the smoothing capacitor 402 is, for example, 22 uF to 100 uF. The DC power converted by the smoothing capacitor 402 is supplied to the charging control unit 403.

  The charging control unit 403 charges the secondary battery 404 using the DC power supplied from the smoothing capacitor 402. The charge control unit 403 performs constant current / constant voltage control, for example, and charges the secondary battery 404.

  The charging control unit 403 is connected to the control unit 204 and has a configuration capable of serial communication, for example. The control unit 204 accesses the register of the charging control unit 403, and sets the value of the charging current and the charging voltage for the secondary battery 404. Further, the control unit 204 accesses the register of the charging control unit 403 to acquire charging state information indicating a charging method performed on the secondary battery 404. The charging state information includes information indicating trickle charging or rapid charging as information indicating a method of charging the secondary battery 404.

  The secondary battery 404 is a rechargeable battery such as a lithium ion battery. The secondary battery 404 can also supply power to the camera system unit 205.

  The switch 405 is, for example, a P channel FET. The switch 405 is connected to the switch driving unit 207, and the switch driving unit 207 turns on or off the switch 405. The switch 405 is configured between the rectifying unit 401 and the smoothing capacitor 402. The switch 405 controls so that the power rectified by the rectifying unit 401 is not supplied to the smoothing capacitor 402 or the charging control unit 403 serving as a DC load. Thereby, the switch drive unit 207 turns off the switch 405 and disconnects the load such as the charge control unit 403 from the rectification unit 401 when the electronic device 200 is in the communication mode. When the switch 405 is off, the rectifying unit 401, the smoothing capacitor 402, the charging control unit 403, the secondary battery 404, the camera system unit 205, and the control unit 204 are not connected. For this reason, the power received by the power receiving antenna 201 is not supplied from the rectifying unit 401 to the smoothing capacitor 402, the charging control unit 403, the secondary battery 404, the camera system unit 205, and the control unit 204. As a result, the DC bias voltage from the switch driving unit 207 is reliably applied to the rectifying unit 401.

  When the electronic device 200 is in the power supply mode, the switch driving unit 207 turns on the switch 405 so that the power from the rectifying unit 401 is supplied to the load such as the charging control unit 403. When the switch 405 is on, the rectifying unit 401 is connected to the smoothing capacitor 402, the charge control unit 403, the secondary battery 404, the camera system unit 205, and the control unit 204. Therefore, the power received by the power receiving antenna 201 is supplied from the rectifying unit 401 to the smoothing capacitor 402, the charging control unit 403, the secondary battery 404, the camera system unit 205, and the control unit 204.

  The switch driving unit 207 turns off the switch 405 according to the timing when the electronic device 200 is in the communication mode. As a result, a DC bias signal, which is a DC bias voltage, is supplied to the switch 405, a reverse DC bias voltage is applied to the diode in the rectifier unit 401, and the input impedance of the power control unit 203 is increased.

  Thereby, even when the electronic device 200 includes the power receiving unit 202 as shown in FIG. 3, the input impedance of the power control unit 203 is obtained from a line in which the compensating resonant element 304 a, the compensating resonant element 304 b, and the switch unit 302 are connected in series. High impedance can be achieved.

(Configuration of switch driving unit 207)
Next, an example of the configuration of the switch driving unit 207 will be described with reference to FIG.

  The switch driving unit 207 includes an impedance conversion element 501a, an impedance conversion element 501b, a smoothing capacitor 502a, a smoothing capacitor 502b, a rectifier diode 503a, a rectifier diode 503b, a voltage dividing resistor 504a, and a voltage dividing resistor 504b. Further, the switch driving unit 207 includes a resistor 505, a voltage detection IC 506, a Zener diode 507, an FET 508, and a resistor 509.

  In FIG. 5, the impedance conversion element 501a is a capacitor, but may be a coil or a resistor. In FIG. 5, the impedance conversion element 501b is a capacitor, but may be a coil or a resistor. Hereinafter, a case where the impedance conversion element 501a and the impedance conversion element 501b are capacitors will be described.

The impedance conversion element 501a is connected to the power receiving antenna 201,
The impedance conversion element 501b is connected to the power receiving antenna 201. Since the impedance is increased with respect to the AC amplitude supplied from the power receiving antenna 201, the capacitance value of the impedance conversion element 501a and the capacitance value of the impedance conversion element 501b are reduced. The capacitance value of the impedance conversion element 501a is such that the impedance on the power side viewed from the end of the power receiving antenna 201 in the power supply mode is higher than the impedance on the communication side viewed from the end of the power receiving antenna 201 in the communication mode. To.

  The capacitance value of the impedance conversion element 501b is such that the impedance on the power side viewed from the end of the power receiving antenna 201 in the power supply mode is higher than the impedance on the communication side viewed from the end of the power receiving antenna 201 in the communication mode. To. The power side viewed from the end of the power receiving antenna 201 is the resonant element 301a and resonant element 301b side, and the communication side viewed from the end of the power receiving antenna 201 is the switch unit 303 side. The capacitance value of the impedance conversion element 501a and the capacitance value of the impedance conversion element 501b are, for example, about 10 pF. Thus, the power received by the power receiving antenna 201 is not supplied to the switch driving unit 207 so much. In this case, the power received by the power receiving antenna 201 is supplied to the switch unit 303 when the electronic device 200 is in the communication mode, and is supplied to the resonance element 301a and the resonance element 301b when the electronic device 200 is in the power supply mode. The

  Therefore, even when the switch driving unit 207 is connected to the power receiving antenna 201, the resonance circuit of the electronic device 200 and the resonance frequency of the electronic device 200 can be prevented from being affected. As a result, the influence of the switch driving unit 207 on the resonance between the power feeding device 100 and the electronic device 200 is reduced, so that the power feeding efficiency and the communication sensitivity are reduced due to the influence on the resonance between the power feeding device 100 and the electronic device 200. Can be prevented.

  The smoothing capacitor 502a has a capacitance value larger than the capacitance value of the impedance conversion element 501a, and has a capacitance value larger than the capacitance value of the impedance conversion element 501b.

  The smoothing capacitor 502b has a capacitance value larger than the capacitance value of the impedance conversion element 501a, and has a capacitance value larger than the capacitance value of the impedance conversion element 501b.

  The rectifier diode 503a and the rectifier diode 503b are, for example, Schottky barrier diodes. Since the rectifier diode 503a and the rectifier diode 503b do not need to pass a large current, they are not diodes that allow a large current to be used in the rectifier unit 401, but are diodes having a small rated current value.

  Most of the power received by the power receiving antenna 201 is supplied to the communication unit 206 or the power control unit 203 by the impedance conversion element 501a and the impedance conversion element 501b. In this case, only a small amount of the electric power received from the power receiving antenna 201 is supplied to the switch driving unit 207. Since the input voltage from the power receiving antenna 201 is lowered via the impedance conversion element 501a and the impedance conversion element 501b, the switch driving unit 207 may not be able to output a voltage for driving the switch unit 302, the switch unit 303, and the switch 405. is there.

  In order to solve this problem, the switch driving unit 207 uses a smoothing capacitor 502a, a smoothing capacitor 502b, a rectifying diode 503a, and a rectifying diode 503b as a rectifying circuit that boosts and outputs an input voltage input from the power receiving antenna 201. The input voltage is doubled and output by a rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifying diode 503a, and the rectifying diode 503b.

  Note that the switch driving unit 207 may have any circuit that can output a voltage for driving the switch unit 302, the switch unit 303, and the switch 405 based on the input voltage input from the power receiving antenna 201. Therefore, when the input voltage from the power receiving antenna 201 is sufficient as a voltage for driving the switch unit 302, the switch unit 303, and the switch 405, the switch driving unit 207 may use another circuit. In this case, the switch driver 207 may use a half-wave rectifier circuit using one diode instead of the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifier diode 503a, and the rectifier diode 503b.

  In addition, when the input voltage from the power receiving antenna 201 is not sufficient as a voltage for driving the switch unit 302, the switch unit 303, and the switch 405, the switch driving unit 207 may use another circuit. In this case, the switch driving unit 207 is provided with two stages of rectifying / smoothing circuits including a smoothing capacitor 502a, a smoothing capacitor 502b, a rectifying diode 503a, and a rectifying diode 503b, and outputs the input voltage as a quadruple voltage. Also good.

  The voltage dividing resistor 504a and the voltage dividing resistor 504b are connected in series between the output from the rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifying diode 503a, and the rectifying diode 503b and GND. The voltage dividing resistor 504a and the voltage dividing resistor 504b have impedance values such that the voltage value of the voltage dividing resistor 504a is adjusted to an appropriate value. The voltage of the voltage dividing resistor 504a is a potential difference between GND and the contacts of the voltage dividing resistor 504a and the voltage detection IC 506.

  The voltage of the voltage dividing resistor 504a is detected by the voltage detection IC 506.

  Further, the impedance value of the voltage dividing resistor 504a and the voltage dividing resistor 504b is a predetermined value (for example, 1.5V) in which the voltage of the voltage dividing resistor 504a is a threshold value of the voltage detection IC 506 when the electronic device 200 is in the power supply mode. It is set to exceed. Furthermore, the impedance values of the voltage dividing resistor 504a and the voltage dividing resistor 504b are set so that the voltage of the voltage dividing resistor 504a does not exceed a predetermined value when the electronic device 200 is in the communication mode. The voltage of the voltage dividing resistor 504a is hereinafter referred to as “switching detection voltage”.

  The voltage detection IC 506 is an IC that detects whether or not the switching detection voltage exceeds a predetermined value (for this reason, the voltage detection IC is also referred to as a voltage detection unit). Further, the output of the voltage detection IC 506 may be an open drain output. The predetermined value has a hysteresis characteristic to prevent erroneous detection.

  The resistor 505 is a pull-up resistor connected in series between the output from the rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifying diode 503a, and the rectifying diode 503b and the FET 508. Since the resistor 505 does not need to pass a large current, the impedance value of the resistor 505 may be, for example, 100 kΩ or more.

  The Zener diode 507 is used for suppressing an output voltage from the rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifying diode 503a, and the rectifying diode 503b from excessively increasing. For example, when the gate breakdown voltage of the FET 508 is 10V, a Zener diode that generates a Zener effect at 9V is used as the Zener diode 507.

  The FET 508 is an FET used to match high or low logic when the switch unit 302, the switch unit 303, and the switch 405 are controlled. The FET 508 is, for example, an N-channel FET. Since the switch driving unit 207 is a high impedance input, a large amount of power is not supplied from the power receiving antenna 201, so it is desirable to use a voltage driven FET for logic matching. In addition, when logic alignment is not necessary, the resistor 505 and the FET 508 need not be provided.

  The voltage detection IC 506 and the power receiving unit 202 are connected, and a power selection signal is supplied to the switch unit 303 as an output from the voltage detection IC. When the high-level power selection signal is supplied to the switch unit 303, the switch unit 303 is turned off. When the low-level power selection signal is supplied to the switch unit 303, the switch unit 303 is turned on.

  In addition, since the FET 508 and the power receiving unit 202 are connected and the FET 508 and the power control unit 203 are connected, a communication selection signal is output to the switch unit 302 and the switch 405 as an output from the drain of the FET 508.

  When a high-level communication selection signal is supplied to the switch unit 302, the switch unit 303 is turned on. When a low-level communication selection signal is supplied to the switch unit 302, the switch unit 302 is turned off. When a high level communication selection signal is supplied to the switch 405, the switch 405 is turned off. When a low level communication selection signal is supplied to the switch 405, the switch 405 is turned on.

  Further, the output from the rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifying diode 503a, and the rectifying diode 503b and the power control unit 203 are connected through a resistor 509. An output from a rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifying diode 503a, and the rectifying diode 503b is applied to the power control unit 203 as a DC bias signal.

  The output from the rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifier diode 503a, and the rectifier diode 503b is connected to the communication unit 206. An output from a rectifying / smoothing circuit including the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifying diode 503a, and the rectifying diode 503b is applied to the communication unit 206 as an activation signal. This is because depending on the configuration of the communication unit 206, when communication is performed by the electronic device 200, when power other than carrier power is further supplied from the power receiving unit 202 to the communication unit 206, the communication sensitivity of the communication unit 206 is improved. Because there are cases.

  The power selection signal and the communication selection signal are output in accordance with outputs from the smoothing capacitor 502a, the smoothing capacitor 502b, the rectifier diode 503a, and the rectifier diode 503b. However, another rectifying / smoothing circuit and another impedance conversion element may be connected to the power receiving antenna 201 to output a DC bias signal to the power control unit 203.

  As described above, when the electronic device 200 has the switch driving unit 207 of FIG. 5, even when the remaining capacity of the secondary battery 404 is 0, the electronic device 200 is switched by the power received from the power feeding device 100 by the power receiving antenna 201. The unit 302 and the switch unit 303 can be controlled.

  Furthermore, the electronic device 200 can prevent the resonance circuit of the electronic device 200 and the resonance frequency of the electronic device 200 from being affected by using the switch driving unit 207 of FIG.

(Voltage waveform during switching operation)
Next, the voltage of each part when the operation mode of the electronic device 200 is switched to the communication mode or the power supply mode will be described with reference to FIG.

  FIG. 7 shows the voltage at the end of the power receiving antenna 201, the switching detection voltage, the voltage of the power selection signal output from the voltage detection IC 506, the voltage of the communication selection signal output from the drain of the FET 508, and the input voltage of the communication unit 206. It is.

  As shown in FIG. 7, the voltage waveform at the end of the power receiving antenna 201 becomes small during the period in which the electronic device 200 is in the communication mode (communication period in FIG. 7), and the period in which the electronic device 200 is in the power supply mode (FIG. 7). The period of power supply in (1) becomes larger.

  The electronic device 200 needs to periodically enter the communication mode in order to perform communication for notifying the power supply device 100 of the state of the electronic device 200 and the state of the secondary battery 404. For this reason, the electronic device 200 switches the operation mode of the electronic device 200 alternately between the communication mode and the power supply mode until the wireless power supply by the power supply device 100 ends.

  As shown in FIG. 7, the waveform of the switching detection voltage changes according to the voltage at the power receiving antenna 201 end. When the waveform of the switching detection voltage is equal to or higher than the threshold value corresponding to the voltage level A, the communication selection signal becomes a high level. In this case, the power selection signal is at a low level. In this case, the switch unit 302 and the switch unit 303 are turned on, and the switch 405 is turned off. The switch unit 302 and the switch unit 303 are not turned on until the waveform of the switching detection voltage becomes equal to or higher than the threshold corresponding to the voltage level A.

  When the waveform of the switching detection voltage is equal to or greater than the threshold corresponding to the voltage level C, the communication selection signal is at a low level and the power selection signal is at a high level. In this case, the switch unit 302 and the switch unit 303 are turned off, and the switch 405 is turned on. The threshold value corresponding to the voltage level C is a predetermined value used in the voltage detection IC 506. Since the predetermined value of the voltage detection IC 506 has a hysteresis characteristic, when the switching detection voltage increases, it becomes a threshold value corresponding to the voltage level C.

  If the waveform of the switching detection voltage becomes equal to or higher than the threshold value corresponding to the voltage level C and then the waveform of the switching detection voltage becomes lower than the threshold value corresponding to the voltage level B, the communication selection signal becomes high level and the power The selection signal becomes low level. In this case, the switch unit 302 and the switch unit 303 are turned on, and the switch 405 is turned off. The threshold value corresponding to the voltage level B is a predetermined value used in the voltage detection IC 506. The predetermined value of the voltage detection IC 506 is a threshold corresponding to the voltage level B when the switching detection voltage decreases.

  As shown in FIG. 7, the waveform of the input voltage of the communication unit 206 increases during the period in which the electronic device 200 is in the communication mode (communication period in FIG. 7), and the period in which the electronic device 200 is in the power supply mode (FIG. 7). The period of power supply in (1) becomes smaller. This is because during the period in which the electronic device 200 is in the power supply mode (power supply period in FIG. 7), the switch unit 303 is turned off and the power receiving antenna 201 and the communication unit 206 are controlled not to be connected. However, the amplitude of the waveform of the input voltage of the communication unit 206 is not zero because the leaked voltage is supplied to the communication unit 206 even when the switch unit 303 is off.

  Further, even if the power supply device 100 outputs a large amount of power due to an error or the like, the electronic device 200 can perform control so that excessive power is not supplied to the communication unit 206 in accordance with an increase in the switching detection voltage.

As described above, the electronic device 200 has the remaining capacity of the secondary battery 404 of 0,
Using the power received from the power feeding device 100 by the power receiving antenna 201, the electronic device 200 can be switched between the power feeding mode and the communication mode. As a result, the electronic device 200 can prevent the second power from being supplied to the communication unit 206 even when the second power is output from the power supply device 100, so that the communication unit 206 can be protected. it can. In addition, the electronic device 200 can prevent the first power from being supplied to the power control unit 203 even if the first power is output from the power supply device 100. Furthermore, the electronic device 200 can prevent the resonance circuit of the electronic device 200 and the resonance frequency of the electronic device 200 from being affected by using the switch driving unit 207 of FIG. For this reason, even if the electronic device 200 uses the switch driving unit 207, the influence on the resonance between the power supply device 100 and the electronic device 200 is reduced. A decrease in power supply efficiency and a decrease in communication sensitivity can be prevented.

(Example 2)
In the first embodiment, the switch driving unit 207 controls the switch unit 302, the switch unit 303, and the switch 405 using the power supplied from the power receiving antenna 201. In the second embodiment, a case where the switch driving unit 207 controls the switch unit 302, the switch unit 303, and the switch 405 using the power supplied from the secondary battery 404 will be described.

  FIG. 2B shows an example of the configuration of the electronic device 200 according to the second embodiment. FIG. 8 illustrates an example of the switch driving unit 207 according to the second embodiment. Descriptions of configurations and functions common to the first embodiment are omitted.

  2B differs from FIG. 2A in that a connection line between the power control unit 203 and the switch drive unit 207 is added, and a connection line between the switch drive unit 207 and the control unit 204 is added.

  A connection line between the switch drive unit 207 and the power control unit 203 is a supply line indicating supply of power from the secondary battery 404 to the switch drive unit 207. In addition, the connection line between the switch drive unit 207 and the control unit 204 is for the control unit 204 receiving power supply from the secondary battery 404 to permit the supply of power from the secondary battery 404 to the switch drive unit 207. This is a signal line.

  Next, an example of the configuration of the switch driving unit 207 according to the second embodiment will be described with reference to FIG.

  In FIG. 8, the switch driving unit 207 includes a switch 801 for connecting a supply line connected to the secondary battery 404. Further, the switch driving unit 207 includes a resistor 802a disposed between the switch 801 and the drain of the FET 508, and a resistor 802b disposed between the switch 801 and the resistor 509.

  When the switch 801 is turned on, the supply line connected to the secondary battery 404 is connected to a line that outputs a DC bias signal to the power control unit 203 via the resistor 802b. In this case, a DC bias signal is supplied to the power control unit 203 according to the power supplied from the secondary battery 404. Further, when the switch 801 is turned on, the supply line of the secondary battery 404 is connected to a line that outputs a communication selection signal via the resistor 802a. In this case, a high-level communication selection signal or a low-level communication selection signal is output according to the power supplied from the secondary battery 404.

  The electronic device 200 includes the switch driving unit 207 in FIG. 8, so that the electric power stored in the secondary battery 404 can be used for the operation of the switch driving unit 207.

  When the remaining capacity of the secondary battery 404 is equal to or greater than a predetermined remaining capacity, the control unit 204 turns on the switch 801 using the power supplied from the secondary battery 404. As a result, the supply line connected to the secondary battery 404 is connected to the resistor 802a and the resistor 802b, so that power is supplied from the secondary battery 404 to the switch drive unit 207.

  The switch 801 is preferably configured using two FETs or a diode and an FET in order to prevent backflow.

  The switch 801 may be a diode. In this case, even if the control unit 204 does not control the switch 801 to be turned on, if the remaining capacity of the secondary battery 404 is greater than or equal to a predetermined remaining capacity, the secondary battery 404 switches to the switch driving unit 207. Power is supplied.

  The resistors 802a and 802b are pull-up resistors. The resistors 802a and 802b pull up the signal line with the voltage of the secondary battery 404. As a result, even when power is not supplied from the power receiving antenna 201 to the switch drive unit 207, if the remaining capacity of the secondary battery 404 is equal to or greater than the predetermined remaining capacity, the switch drive unit 207 via the switch 801. Is supplied with power. Further, the supply line of the secondary battery 404 may be connected to a line that outputs an activation signal. Furthermore, the supply line connected to the secondary battery 404 may be connected to a line that outputs a power selection signal. For this reason, the switch drive unit 207 can control the switch unit 302, the switch 303, and the switch 405 using the power supplied from the secondary battery 404.

  Thus, when the remaining capacity of the secondary battery 404 is greater than or equal to the predetermined remaining capacity, the electronic device 200 according to the second embodiment supplies the power supplied from the secondary battery 404 to the switch driving unit 207. did. Accordingly, the switch driving unit 207 can control the switch unit 302, the switch 303, and the switch 405, so that even when power is not supplied from the power receiving antenna 201, the electronic device 200 can be set to the power supply mode. Can be in communication mode. In the second embodiment, when the remaining capacity of the secondary battery 404 is not equal to or greater than the predetermined remaining capacity, the switch driving unit 207 in the second embodiment performs the same operation as in the first embodiment.

  In the second embodiment, the same configuration and function as in the first embodiment have the same effects as in the first embodiment.

  In the first and second embodiments, the resonance frequency f is described as being 13 and 56 MHz. However, the resonance frequency f may be 50/60 Hz which is a commercial frequency, and a frequency of 6.78 MHz. It may be. Moreover, the frequency between 100 KHz and 250 KHz may be sufficient.

DESCRIPTION OF SYMBOLS 201 ... Power receiving antenna, 202 ... Power receiving part, 203 ... Power control part, 204 ... Control part, 205 ... Camera system part, 206 ... Communication part, 301 ... Resonance element, 302 ... Switch part, 303 ... Switch part, 304 ... Compensation Resonant element

Claims (13)

An antenna for receiving power wirelessly;
A power control unit for inputting and storing or distributing power received by the antenna;
A communication unit that communicates with an external device via the antenna;
A switching unit that switches a path from the antenna to the power control unit and the communication unit;
A drive unit that operates with power received by the antenna and drives the switching unit;
The input impedance of the drive unit viewed from the antenna is higher than the input impedance of either the power control unit side or the communication unit side viewed from the antenna.
An electronic device characterized by that. An antenna for receiving power wirelessly;
A power control unit for inputting and storing or distributing power received by the antenna;
A communication unit that communicates with an external device via the antenna;
A switching unit that switches a path from the antenna to the power control unit and the communication unit;
A drive unit for driving the switching unit,
The drive unit is configured to be connected to the antenna via a conversion element that converts impedance.
An electronic device characterized by that. The switching unit includes at least a first switch connected to an input of the communication unit and a second switch connected to an input of the power control unit,
The electronic device according to claim 1, wherein the electronic device is an electronic device. The input impedance of the driving unit viewed from the antenna is the input impedance on the communication unit side when the first switch viewed from the antenna is non-conductive, or the second switch viewed from the antenna is non-conductive Lower than the input impedance on the power control unit side in the state,
The electronic device according to claim 3. The drive unit is
A conversion element that increases impedance with respect to the AC amplitude input from the antenna;
A rectifier circuit connected to the conversion element;
A voltage detection unit that detects a voltage value rectified by the rectifier circuit;
The electronic device according to claim 1, wherein the electronic device is any one of claims 1 to 3. The drive unit is
A rectifier circuit connected to the conversion element;
Having at least a voltage detector for detecting a voltage value after being rectified by the rectifier circuit;
The electronic device according to claim 2, wherein the electronic device is an electronic device. The rectifier circuit is a circuit that rectifies a voltage higher than an input voltage.
The electronic device according to claim 5, wherein the electronic device is an electronic device. The conversion element is at least one of a capacitor, a coil, or a resistor,
The electronic device according to claim 5, wherein the electronic device is an electronic device. When the detection voltage detected by the voltage detection unit exceeds a second threshold value that is greater than the first threshold value, the driving unit causes the switch connected to the input of the power control unit to conduct, and the first threshold value A signal that makes a switch connected to the input of the communication unit conductive, if it is between the second threshold value and
The electronic device according to claim 6, wherein the electronic device is an electronic device. The second threshold value has a hysteresis characteristic, and the second threshold value includes a case where the detection voltage increases and exceeds the second threshold value, and a case where the detection voltage decreases and exceeds the second threshold value. The threshold is different,
The electronic apparatus according to claim 9. A power supply unit for supplying power separately from the power received by the antenna;
The drive unit further operates with the power supplied from the power supply unit.
The electronic device according to claim 1, wherein the electronic device is an electronic device. The drive unit outputs power different from the power input from the antenna by the communication unit to the communication unit.
The electronic device according to claim 1, wherein the electronic device is an electronic device. Further comprising a resonant circuit with the antenna;
Changing the configuration of the resonant circuit by switching the path by the switching unit,
The electronic device according to claim 1, wherein the electronic device is an electronic device.