Wireless Power Receiver

Abstract

A wireless power reception device (10) includes power reception coils (211, 221, 231, 241), power reception resonance circuits (210, 220, 230, 240), and rectifier circuits (31-34). Power reception current is generated in each of the power reception coils (211, 221, 231, 241) as a result of coupling to an external magnetic field. The power reception resonance circuit (210) is configured by including the power reception coil (211) and a capacitor (212); the power reception resonance circuit (220) is configured by including the power reception coil (221) and a capacitor (222); the power reception resonance circuit (230) is configured by including the power reception coil (231) and a capacitor (232); and the power reception resonance circuit (240) is configured by including the power reception coil (241) and a capacitor (242). The rectifier circuits (31-34) are respectively connected to the power reception resonance circuits (210, 220, 230, 240), and rectify resonance current. The power reception coils (211, 221) are flat spiral coils, and the power reception coils (231, 241) are cylindrical solenoid coils. The power reception coils (211. 221) and the power reception coils (231, 241) are disposed in a state in which the plane of the spiral coils and the axis of the cylindrical shape of the solenoid coils are non-parallel. In a stage after the rectifier circuits (31-34), an electrical power add circuit (40) adds DC output of the rectifier circuits (31-34) and supplies electrical power to a load (72).

Description

[Technical Field]

[0001] The present invention relates to a wireless power receiving device that includes a power receiving coil in a housing having a complex shape. [Background technology]

[0002] Patent Document 1 describes a hearing aid that includes a housing formed in the shape of an auricle and a coil member disposed within the housing.

[0003] The hearing aid described in Patent Document 1 uses two coil members. The two coil members are planar coils and are arranged parallel to each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-40860 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the configuration described in Patent Document 1, the hearing aid must be placed in a specific position relative to the power transmission stand (power transmission coil) in order to receive power efficiently.

[0006] In particular, devices with complex, three-dimensional housings, such as hearing aids, are not always placed in the same position on the power transmission stand, which can result in power not being received or a significant drop in power receiving efficiency.

[0007] Therefore, an object of the present invention is to provide a wireless power receiving device that can suppress a decrease in power receiving efficiency due to the placement posture on a power transmitting stand (power transmitting coil). [Means for solving the problem]

[0008] The wireless power receiver of the present invention includes a first power receiving coil, a second power receiving coil, a load, a first power receiving resonant circuit, a second power receiving resonant circuit, a first rectifier circuit, and a second rectifier circuit. The first power receiving coil and the second power receiving coil each generate a receiving current by coupling to an external magnetic field. The load is driven by power based on the receiving current. The first power receiving resonant circuit includes a first power receiving coil and a first resonant capacitor, and the second power receiving resonant circuit includes a second power receiving coil and a second resonant capacitor. The first rectifier circuit is connected to the first power receiving resonant circuit and rectifies the resonant current of the first power receiving resonant circuit to supply power to the load. The second rectifier circuit is connected to the second power receiving resonant circuit and rectifies the resonant current of the second power receiving resonant circuit to supply power to the load.

[0009] The first receiving coil is a planar spiral coil, and the second receiving coil is a cylindrical solenoid coil. The first receiving coil and the second receiving coil are arranged so that the direction perpendicular to the plane of the spiral coil is non-parallel to the cylindrical axis of the solenoid coil. The power adding circuit, located downstream of the first rectifier circuit and the second rectifier circuit, adds the DC output of the first rectifier circuit and the DC output of the second rectifier circuit and supplies power to a load.

[0010] In this configuration, the first and second power receiving coils can be appropriately positioned according to the shape of the housing of the wireless power receiving device, and even if magnetic flux interlinks with the housing in multiple different directions, either the first or second power receiving coil can receive power efficiently. Furthermore, the DC output obtained from the first and second power receiving coils is added together and supplied to the load, enabling efficient power reception regardless of the attitude of the wireless power receiving device. [Effects of the Invention]

[0011] According to this invention, it is possible to increase the freedom of placement of the power receiving device, regardless of the placement orientation of the wireless power receiving device on the power transmitting stand (power transmitting coil), thereby enabling efficient power reception, and even in a housing with a complex three-dimensional shape, it is possible to effectively utilize both the planar spatial area and the cylindrical spatial area, thereby realizing a small power receiving device with excellent power receiving performance. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a circuit diagram of a wireless power receiving device according to an embodiment of the present invention. [Figure 2] 2(A), 2(B), 2(C), and 2(D) are diagrams showing a schematic structure of a wireless power receiving device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a perspective view showing the appearance of the wireless power receiving device according to the embodiment of the present invention. [Figure 4] FIG. 4A is a plan view showing an example of a flat spiral coil, and FIG. 4B is an E-E cross-sectional view of FIG. 4A. [Figure 5] FIG. 5(A) is a side view of the solenoid coil, and FIG. 5(B) is an end view of the solenoid coil. [Figure 6] 6(A), 6(B), and 6(C) are diagrams showing a case where a wireless power receiving device is placed on a power supply stand and power is supplied. [Figure 7] 7A and 7B are diagrams showing a schematic structure of a wireless power receiving device according to a variation of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] A wireless power receiving device according to an embodiment of the present invention will be described with reference to the drawings.

[0014] (Circuit configuration of wireless power receiving device 10) (Connection configuration) FIG. 1 is a circuit diagram of a wireless power receiving device according to an embodiment of the present invention.

[0015] As shown in FIG. 1, the wireless power receiving device 10 includes a power receiving coil 211, a power receiving coil 221, a power receiving coil 231, a power receiving coil 241, a capacitor 212, a capacitor 222, a capacitor 232, and a capacitor 242.

[0016] The wireless power receiving device 10 also includes a rectifier circuit 31, a rectifier circuit 32, a rectifier circuit 33, a rectifier circuit 34, a power adding circuit 40, a control circuit 50, a voltage conversion circuit 61, a charge / discharge control circuit 62, a secondary battery 71, and a load 72.

[0017] A capacitor 212 is connected in parallel to the power receiving coil 211. The parallel circuit of the power receiving coil 211 and the capacitor 212 constitutes a power receiving resonant circuit 210. A capacitor 222 is connected in parallel to the power receiving coil 221. The parallel circuit of the power receiving coil 221 and the capacitor 222 constitutes a power receiving resonant circuit 220.

[0018] A capacitor 232 is connected in parallel to the power receiving coil 231. A parallel circuit of the power receiving coil 231 and the capacitor 232 constitutes a power receiving resonant circuit 230. A capacitor 242 is connected in parallel to the power receiving coil 241. A parallel circuit of the power receiving coil 241 and the capacitor 242 constitutes a power receiving resonant circuit 240.

[0019] The power receiving coil 211 and the power receiving coil 221 correspond to the "first power receiving coil" of the present invention, and the power receiving coil 231 and the power receiving coil 241 correspond to the "second power receiving coil" of the present invention. The capacitor 212 and the capacitor 222 correspond to the "first resonant capacitor" of the present invention, and the capacitor 232 and the capacitor 242 correspond to the "second resonant capacitor" of the present invention. The power receiving resonant circuit 210 and the power receiving resonant circuit 220 correspond to the "first power receiving resonant circuit" of the present invention, and the power receiving resonant circuit 230 and the power receiving resonant circuit 240 correspond to the "second power receiving resonant circuit" of the present invention.

[0020] The output terminal of the power receiving resonant circuit 210 is connected to the input terminal of the rectifier circuit 31, and the output terminal of the power receiving resonant circuit 220 is connected to the input terminal of the rectifier circuit 32. The output terminal of the power receiving resonant circuit 230 is connected to the input terminal of the rectifier circuit 33, and the output terminal of the power receiving resonant circuit 240 is connected to the input terminal of the rectifier circuit 34. The rectifier circuits 31 and 32 correspond to the "first rectifier circuit" of the present invention, and the rectifier circuits 33 and 34 correspond to the "second rectifier circuit" of the present invention.

[0021] The output terminal of the rectifier circuit 31 , the output terminal of the rectifier circuit 32 , the output terminal of the rectifier circuit 33 and the output terminal of the rectifier circuit 34 are connected to a power adding circuit 40 .

[0022] The output terminal of the power adding circuit 40 is connected to the control circuit 50 and the input terminal of the voltage conversion circuit 61. The output terminal of the voltage conversion circuit 61 is connected to the input terminal of the charge / discharge control circuit 62. The output terminal of the charge / discharge control circuit 62 is connected to the secondary battery 71 and the load 72.

[0023] The secondary battery 71 is, for example, a thin battery, which makes it easy to accommodate the secondary battery 71 in the housing 100 (described later), and prevents the housing 100 from becoming too large.

[0024] The load 72 is a circuit or the like that executes the function of a device realized by the wireless power receiving device 10, and for example, if the wireless power receiving device 10 is a hearing aid, it is configured by a microphone, an amplifier circuit for audio signals, and the like.

[0025] (Operation of the wireless power receiving device 10) Power receiving coil 211, power receiving coil 221, power receiving coil 231, and power receiving coil 241 each generate a receiving current by coupling to an external magnetic field. More specifically, when a device equipped with wireless power receiver 10 is placed on a power supply stand, power receiving coil 211, power receiving coil 221, power receiving coil 231, and power receiving coil 241 couple to an alternating magnetic field generated by a current flowing through the power supply coil of the power supply stand, and generate a receiving current. In this case, the magnitude of the receiving current generated by power receiving coil 211, power receiving coil 221, power receiving coil 231, and power receiving coil 241 varies depending on the position of the device relative to the power supply stand.

[0026] At this time, the resonant frequencies of the power receiver resonant circuit 210, the power receiver resonant circuit 220, the power receiver resonant circuit 230, and the power receiver resonant circuit 240 are adjusted to the frequency of the alternating magnetic field (in other words, the drive frequency for generating the power feeding current of the power feeding device). As a result, an electromagnetic resonant field is formed between the power feeding coil and the power receiving coils coupled to the alternating magnetic fields of the power receiving coil 211, the power receiving coil 221, the power receiving coil 231, and the power receiving coil 241. As a result, low-loss power reception is possible. The frequency of the alternating magnetic field is, for example, 6.78 MHz or 13.56 MHz. This makes it possible to use the ISM band for wireless power feeding.

[0027] The power receiving resonant circuit 210 outputs a resonant current based on the power receiving current of the power receiving coil 211. The power receiving resonant circuit 220 outputs a resonant current based on the power receiving current of the power receiving coil 221. The power receiving resonant circuit 230 outputs a resonant current based on the power receiving current of the power receiving coil 231. The power receiving resonant circuit 240 outputs a resonant current based on the power receiving current of the power receiving coil 241.

[0028] The rectifier circuit 31 rectifies the resonant current of the power receiving resonant circuit 210 and outputs a first DC current. The rectifier circuit 32 rectifies the resonant current of the power receiving resonant circuit 220 and outputs a second DC current. The rectifier circuit 33 rectifies the resonant current of the power receiving resonant circuit 230 and outputs a third DC current. The rectifier circuit 34 rectifies the resonant current of the power receiving resonant circuit 240 and outputs a third DC current.

[0029] The power adder circuit 40 is configured by an OR circuit. The power adder circuit 40 adds the first DC current, the second DC current, the third DC current, and the fourth DC current, and outputs an added combined current. The DC power resulting from this added combined current is supplied to the secondary battery 71 and the load 72 via the voltage conversion circuit 61 and the like.

[0030] As a more specific circuit configuration, the power adder circuit 40 includes diodes D41, D42, D43, D44, and a resistor R40. The anode of diode D41 is connected to the Hi-side output terminal of rectifier circuit 31. The anode of diode D42 is connected to the Hi-side output terminal of rectifier circuit 32. The anode of diode D43 is connected to the Hi-side output terminal of rectifier circuit 33. The anode of diode D44 is connected to the Hi-side output terminal of rectifier circuit 34. The cathodes of diodes D41, D42, D43, and D44 are connected to one another and to the Hi-side output terminal of the power adder circuit 40. Resistor R40 is connected between the Hi-side output terminal and the Low-side output terminal of the power adder circuit 40.

[0031] The control circuit 50 is driven by receiving the output power of the power adding circuit 40 and controls the operation of the voltage conversion circuit 61 and the charge / discharge control circuit 62 .

[0032] Under control of the control circuit 50, the voltage conversion circuit 61 converts the input voltage from the power adding circuit 40 to a predetermined voltage value and outputs it to the charge / discharge control circuit 62. Under control of the control circuit 50, the charge / discharge control circuit 62 outputs a charging current to charge the secondary battery 71 using the power supplied from the voltage conversion circuit 61. The charge / discharge control circuit 62 also outputs the current input from the secondary battery 71 to the load 72. In other words, power is supplied from the secondary battery 71 to the load 72. Note that, although the embodiment shown here has the charge / discharge control circuit 62, secondary battery 71, and load 72 provided separately, the charge / discharge control circuit 62 and secondary battery 71 may also be included as part of the load 72.

[0033] (Structure of wireless power receiving device 10) Figures 2(A), 2(B), 2(C), and 2(D) are diagrams showing the schematic structure of a wireless power receiving device according to an embodiment of the present invention. Figures 2(A), 2(B), 2(C), and 2(D) are diagrams showing the wireless power receiving device viewed from different directions. Figure 3 is a perspective view of the appearance of a wireless power receiving device according to an embodiment of the present invention. Note that, in the following, to make the shape easier to understand, the x-axis, y-axis, and z-axis directions will be used for explanation, but the x-axis, y-axis, and z-axis simply refer to three axes that are perpendicular to each other.

[0034] 2(A), 2(B), 2(C), 2(D), and 3, the wireless power receiving device 10 includes a housing 100. The housing 100 includes a surface 101, a surface 102, a surface 103, a surface 104, a surface 105, and a surface 106. The housing 100 of the wireless power receiving device 10 is shaped to fit the shape of the auricle, but the following description will focus on the parts related to the key points of the invention.

[0035] Surfaces 101 and 102 are substantially parallel to the x-axis and z-axis directions and are spaced a predetermined distance apart in the y-axis direction. Surfaces 101 and 102 are substantially parallel and face each other. Surface 103 is connected to one end edge of surfaces 101 and 102 in the z-axis direction. Surface 104 is connected to the other end edge of surfaces 101 and 102 in the z-axis direction. Surface 105 is connected to one end edge of surfaces 101 and 102 in the x-axis direction. Surface 106 is connected to the other end edge of surfaces 101 and 102 in the x-axis direction.

[0036] Here, in surfaces 101 and 102, the length in the z-axis direction on one end side in the x-axis direction is longer than the length in the z-axis direction on the other end side in the x-axis direction. That is, in surfaces 101 and 102, region 110 on the side adjacent to surface 105 is wider than region 120 on the side adjacent to surface 106.

[0037] The circuit elements that realize the above-described circuit configuration are built into the housing 100 having such a shape. Generally, these circuit elements are mounted on a circuit board, and the circuit board on which these circuit elements are mounted is built into the housing 100. The circuit board may be a solid board or a flexible board.

[0038] (Receiving coil structure) In such a configuration, power receiving coil 211, power receiving coil 221, power receiving coil 231, and power receiving coil 241 are arranged in housing 100 in the following shapes and as described below.

[0039] Power receiving coil 211 and power receiving coil 221 are planar spiral coils. Fig. 4(A) is a plan view showing an example of a planar spiral coil, and Fig. 4(B) is an E-E cross-sectional view of Fig. 4(A). Note that although Fig. 4(A) and Fig. 4(B) show power receiving coil 211 as an example, power receiving coil 221 also has a similar configuration.

[0040] The power receiving coil 211 includes a wound linear conductor 2110, an insulating support film 2111, and a magnetic sheet 2112. The linear conductor 2110 is formed on a first surface of the insulating support film 2111. The magnetic sheet 2112 is disposed on a second surface of the insulating support film 2111. The linear conductor 2110 and the magnetic sheet 2112 are disposed in parallel.

[0041] With this configuration, power receiving coil 211 is highly coupled to magnetic flux in a direction perpendicular to the plane on which linear conductor 2110 is formed.

[0042] Power receiving coil 231 and power receiving coil 241 are tubular (e.g., cylindrical) solenoid coils. Fig. 5(A) is a side view of the solenoid coil, and Fig. 5(B) is an end view of the solenoid coil. Note that although Fig. 5(A) and Fig. 5(B) illustrate power receiving coil 231 as an example, power receiving coil 241 also has a similar configuration.

[0043] Power receiving coil 231 includes cylindrical spiral linear conductor 2310 and cylindrical magnetic core 2311. Magnetic core 2311 is disposed in the space inside the spiral of linear conductor 2310.

[0044] With this configuration, the power receiving coil 231 is highly coupled to the magnetic flux in the axial direction of the spiral.

[0045] (Arrangement of each receiving coil in the housing) 2(A), 2(B), 2(C), 2(D), and 3, power receiving coil 211 is disposed inside housing 100 at a position close to surface 101. In this case, power receiving coil 211 is disposed so that a plane formed by wound linear conductor 2110 and surface 101 are substantially parallel (so that the x-axis of housing 100 and the x1-axis of power receiving coil 211 are substantially parallel). Furthermore, power receiving coil 211 is disposed in housing 100 so that linear conductor 2110 is disposed closer to surface 101 than magnetic sheet 2112.

[0046] Power receiving coil 221 is disposed inside housing 100 at a position close to surface 102. In this case, power receiving coil 221 is disposed so that the plane formed by the wound linear conductor is approximately parallel to surface 102 (so that the x-axis of housing 100 and the x1-axis of power receiving coil 221 are approximately parallel). Furthermore, power receiving coil 221 is disposed in housing 100 so that the linear conductor is disposed closer to surface 102 than the magnetic sheet.

[0047] The power receiving coil 211 and the power receiving coil 221 are arranged in an area 110 in the housing 100. As a result, even if the housing 100 is small, the power receiving coil 211 and the power receiving coil 221 are arranged in a position in the housing 100 that has a large area. Therefore, the planar area of ​​the power receiving coil 211 and the power receiving coil 221 can be increased, and the received current can be increased.

[0048] The receiving coil 231 is arranged in the housing 100 so that the axial direction (z2 axis direction) of the spiral linear conductor 2310 is parallel to the z axis direction of the housing 100 (the direction in which the surfaces 103 and 104 are arranged at a distance from each other).

[0049] In this case, power receiving coil 231 is placed in region 110 in housing 100. In region 110, the distance between surface 103 and surface 104 is long. Therefore, power receiving coil 231, whose length in the axial direction (z2 axis direction) is longer than in other directions (x2 axis direction and y2 axis direction), can be placed between surface 103 and surface 104, i.e., inside housing 100.

[0050] The receiving coil 241 is arranged in the housing 100 so that the axial direction (z2 axis direction) of the spiral linear conductor is parallel to the x axis direction of the housing 100 (the direction in which the surfaces 105 and 106 are arranged at a distance from each other).

[0051] In this case, power receiving coil 241 is placed in region 120 in housing 100. In region 120, the distance between surface 103 and surface 104 is short, but the distance in the direction in which surfaces 105 and 106 are spaced apart is long. Therefore, power receiving coil 241, whose length in the axial direction (z2-axis direction) is longer than in other directions (x2-axis direction and y2-axis direction), can be placed between surfaces 105 and 106, i.e., inside housing 100. Furthermore, power receiving coil 241 can be placed in a position in the x-axis direction of housing 100 where it does not overlap with power receiving coil 231 and power receiving coils 211 and 221.

[0052] With this arrangement, the planar spiral coils (receiving coil 211, receiving coil 221) are arranged in housing 100 with the direction perpendicular to the plane of the planar spiral coils and the axial direction of the solenoid coils (receiving coil 231, receiving coil 241) non-parallel.

[0053] With this configuration, power receiving coil 211 and power receiving coil 221 are highly coupled to magnetic flux parallel to the y-axis direction of casing 100. Power receiving coil 231 is highly coupled to magnetic flux parallel to the z-axis direction of casing 100. Power receiving coil 241 is highly coupled to magnetic flux parallel to the x-axis direction of casing 100. That is, the planar spiral coils (power receiving coil 211, power receiving coil 221) are highly coupled to magnetic flux parallel to the y-axis direction, and the solenoid coils (power receiving coil 231, power receiving coil 241) are highly coupled to magnetic flux parallel to the x-axis and z-axis directions, respectively.

[0054] As a result, in the wireless power receiver 10, any one of the power receiver coils 211, 221, 231, and 241 is coupled with a high degree of coupling to magnetic flux in any direction.

[0055] Furthermore, by appropriately arranging planar spiral coils (receiving coil 211, receiving coil 221) and solenoid coils (receiving coil 231, receiving coil 241), each of which has a different shape, according to the shape of the housing 100, the wireless power receiving device 10 can incorporate these receiving coils into the housing 100 even if the housing 100 is small.

[0056] (Placement on power supply stand 190 and power receiving mode) 6(A), 6(B), and 6(C) are diagrams showing a case where a wireless power receiving device is placed on a power supply stand and power is supplied.

[0057] As shown in FIGS. 6(A), 6(B), and 6(C), power is supplied to the wireless power receiver 10 by being placed on a power supply stand 190. The power supply stand 190 has a power supply surface 191. The power supply coil 199 is a planar spiral coil. The power supply coil 199 is disposed near the power supply surface 191 and is disposed parallel to the power supply surface 191. As a result, the magnetic flux generated by the current flowing through the power supply coil 199 is oriented in a direction substantially perpendicular to the power supply surface 191 near the power supply surface 191.

[0058] 6(A), the wireless power receiver 10 is placed on the power feeding surface 191 of the power feeding stand 190 so that the surface 101 is close to (or in contact with) the power feeding surface 191. In this case, the magnetic flux is oriented perpendicular to the plane of the power receiving coil 211, and the power receiving coil 211 is highly coupled to the magnetic flux. As a result, a high receiving current is output from the power receiving coil 211.

[0059] Although not shown, when the surface 102 is close to the power feeding surface 191, the power receiving coil 221 is highly coupled to the magnetic flux, and a high receiving current is output from the power receiving coil 221.

[0060] 6(B), the wireless power receiver 10 is placed on the power feeding surface 191 of the power feeding stand 190 so that the surface 104 is close to (or in contact with) the power feeding surface 191. In this case, the magnetic flux is approximately parallel to the axial direction of the power receiving coil 231, and the power receiving coil 231 is highly coupled to the magnetic flux. This causes a high receiving current to be output from the power receiving coil 231.

[0061] Although not shown, when the surface 103 is close to the power feeding surface 191, the power receiving coil 231 is also highly coupled to the magnetic flux, and a high power receiving current is output from the power receiving coil 231.

[0062] 6(C), the wireless power receiver 10 is placed on the power feeding surface 191 of the power feeding stand 190 so that the surface 106 is close to (or in contact with) the power feeding surface 191. In this case, the magnetic flux is approximately parallel to the axial direction of the power receiving coil 241, and the power receiving coil 241 is highly coupled to the magnetic flux. This causes a high receiving current to be output from the power receiving coil 241.

[0063] Although not shown, when the surface 105 is close to the power feeding surface 191, the power receiving coil 241 is also highly coupled to the magnetic flux, and a high power receiving current is output from the power receiving coil 241.

[0064] As described above, depending on the placement state of the wireless power receiving device 10 on the power supply stand 190, one of the receiving coils 211, 221, 231, and 241 is highly coupled to the magnetic flux generated by the current in the power supply coil 199, and a high receiving current can be output.

[0065] Then, the wireless power receiver 10 converts the output currents of the power receiving coil 211, the power receiving coil 221, the power receiving coil 231, and the power receiving coil 241 into direct currents, adds them together, and supplies them to the secondary battery 71 and the load 72. Therefore, the wireless power receiver 10 can efficiently receive power and supply power to the secondary battery 71 and the load 72 regardless of the position of the wireless power receiver 10 on the power feeding stand 190 (power feeding coil 199).

[0066] (Example of derivative) In the above description, a hearing aid is used as the device to which the wireless power receiving device 10 is applied, but the device can also be applied to other devices. Figures 7(A) and 7(B) are diagrams showing the schematic structure of a wireless power receiving device according to a variation of an embodiment of the present invention. Figures 7(A) and 7(B) are diagrams showing the wireless power receiving device as viewed from different directions.

[0067] As shown in Figures 7(A) and 7(B), the device to which the wireless power receiving device 10A is applied is a wristwatch. The wireless power receiving device 10A has a housing 100A. The housing 100A has a front surface 101A, a back surface 102A, and a side surface 103A. The front surface 101A has an area on which a dial or the like can be placed. The back surface 102A is positioned parallel to and facing the front surface 101A at a predetermined distance. The side surface 103A is perpendicular to the front surface 101A and the back surface 102A and is connected to the outer peripheries of the front surface 101A and the back surface 102A.

[0068] Housing 100A has a large surface area of ​​surface 101A and a small thickness (low side surface 103A).

[0069] Power receiving coil 211, power receiving coil 231, and power receiving coil 241 are disposed inside housing 100A.

[0070] The power receiving coil 211 is placed in the housing 100A so that the plane of the power receiving coil 211 is approximately parallel to the surface 101A. With this configuration, the area of ​​the power receiving coil 211 can be increased.

[0071] Power receiving coil 231 and power receiving coil 241 are arranged in housing 100A so that their axial directions are parallel to surface 101A. With this configuration, power receiving coil 231 and power receiving coil 241 can be arranged even if housing 100A is thin.

[0072] In this configuration, the direction perpendicular to the plane of receiving coil 211, which is a flat spiral coil, the axial direction of receiving coil 231, which is a cylindrical solenoid coil, and the axial direction of receiving coil 241, which is a cylindrical solenoid coil, are all perpendicular to each other.

[0073] This allows the wireless power receiver 10A to suppress a decrease in power receiving efficiency due to the placement posture on the power feed stand (power feeding coil), similar to the wireless power receiver 10. In this case, as described above, the power receiving coils 211, 231, and 241 are appropriately placed according to the shape of the housing 100A of the wireless power receiver 10A, and therefore the housing 100A of the wireless power receiver 10A can be made smaller without a decrease in power receiving efficiency.

[0074] In the above-described embodiment, a plurality of planar spiral coils and / or cylindrical solenoid coils are arranged, but it is also possible to have only one of each. However, it is better to include both planar spiral coils and cylindrical solenoid coils, totaling three or more, since this allows for high coupling to magnetic flux on any of the three orthogonal axes.

[0075] In the above-described embodiment, the direction perpendicular to the plane of the planar spiral coil and the axial direction of the cylindrical solenoid coil are perpendicular to each other. However, the direction perpendicular to the plane of the planar spiral coil and the axial direction of the cylindrical solenoid coil may be non-parallel. In this case, the arrangement of the planar spiral coil and the cylindrical solenoid coil may be determined based on the shape of the housing and the possible mounting configurations on the power supply stand.

[0076] Furthermore, while the above-described embodiments have been given with examples of hearing aids and wristwatches, the shape of the housing of the wireless power receiving device is not limited to these, and the above-described configuration can be more effectively applied to shapes that are not simple three-dimensional shapes but that combine multiple three-dimensional shapes, and can achieve the above-described effects.

[0077] <1> a first receiving coil and a second receiving coil that generate a receiving current by coupling with an external magnetic field; a load driven by power based on the received current; a first power receiving resonant circuit including the first power receiving coil and a first resonant capacitor; a second power receiving resonant circuit including the second power receiving coil and a second resonant capacitor; a first rectifier circuit connected to the first power receiving resonant circuit, rectifying a resonant current of the first power receiving resonant circuit and supplying power to the load; a second rectifier circuit connected to the second power receiving resonant circuit, rectifying a resonant current of the second power receiving resonant circuit and supplying power to the load; Equipped with the first power receiving coil is a planar spiral coil, the second power receiving coil is a cylindrical solenoid coil, the first receiving coil and the second receiving coil are arranged in a state in which a direction perpendicular to a plane of the spiral coil and an axis of a cylindrical shape of the solenoid coil are non-parallel to each other; a current adding circuit, at a downstream stage of each of the first rectifier circuit and the second rectifier circuit, that adds the rectified current of the first rectifier circuit and the rectified current of the second rectifier circuit and supplies power to the load.

[0078] <2> The current addition circuit constitutes a logical OR circuit. <1> The wireless power receiving device according to claim 1.

[0079] <3> The OR circuit is configured using a diode. <2> The wireless power receiving device according to claim 1.

[0080] <4> The plane of the spiral coil and the cylindrical axis of the solenoid coil are perpendicular to each other. <1> ~ <3> 10. The wireless power receiving device according to claim 9, wherein

[0081] <5> The spiral coil includes a wound linear conductor and a magnetic sheet disposed parallel to the wound conductor. <1> ~ <4> 10. The wireless power receiving device according to claim 9, wherein

[0082] <6> The solenoid coil includes a spiral linear conductor and a magnetic core disposed inside the spiral linear conductor. <1> ~ <5> 10. The wireless power receiving device according to claim 9, wherein

[0083] <7> The frequency of the external magnetic field is 6.78 MHz or 13.56 MHz. <1> ~ <6> 10. The wireless power receiving device according to claim 9, wherein

[0084] <8> a first resonant frequency of the first power receiving resonant circuit and a second resonant frequency of the second power receiving resonant circuit are the same; <1> ~ <7> 10. The wireless power receiving device according to claim 9, wherein

[0085] <9> The load includes a secondary battery and a charge / discharge control circuit that controls charging of the secondary battery. <1> ~ <8> 10. The wireless power receiving device according to claim 9, wherein

[0086] <10> The secondary battery is a thin battery. <9> The wireless power receiving device according to claim 1. [Explanation of symbols]

[0087] D41, D42, D43, D44: Diodes R40:Resistor 10, 10A: Wireless power receiving device 31, 32, 33, 34: Rectifier circuit 40: Power addition circuit 50: Control circuit 61: Voltage conversion circuit 62: Charge / discharge control circuit 71: Secondary battery 72: Load 100, 100A: Housing 190: Power supply stand 191: Power supply surface 199: Power supply coil 210, 220, 230, 240: Receiving resonance circuit 211, 221, 231, 241: receiving coils 212, 222, 232, 242: Capacitors 2110: Linear conductor 2111: Insulating support film 2112: Magnetic sheet 2310: Linear conductor 2311:Magnetic core

Claims

1. a first receiving coil and a second receiving coil that generate a receiving current by being coupled to an external magnetic field; a load driven by power based on the received current; a first power receiving resonant circuit including the first power receiving coil and a first resonant capacitor; a second power receiving resonant circuit including the second power receiving coil and a second resonant capacitor; a first rectifier circuit connected to the first power receiving resonant circuit and configured to rectify a resonant current of the first power receiving resonant circuit and output a direct current; a second rectifier circuit connected to the second power receiving resonant circuit and configured to rectify a resonant current of the second power receiving resonant circuit and output a direct current; Equipped with the first power receiving coil is a planar spiral coil, the second power receiving coil is a cylindrical solenoid coil, the first receiving coil and the second receiving coil are arranged in a state in which a direction perpendicular to a plane of the spiral coil and an axis of a cylindrical shape of the solenoid coil are not parallel to each other; a current adding circuit, at a subsequent stage of each of the first rectifier circuit and the second rectifier circuit, for adding a rectified current of the first rectifier circuit and a rectified current of the second rectifier circuit and supplying power to the load; Even if the first power receiving coil and the second power receiving coil form electromagnetic resonance fields and magnetic fluxes interlink in different directions, the DC output of the first rectifier circuit and the DC output of the second rectifier circuit are added together to supply DC power to the load. Wireless power receiving device.

2. The current addition circuit constitutes a logical OR circuit. The wireless power receiving device according to claim 1 .

3. The OR circuit is configured using a diode. The wireless power receiving device according to claim 2 .

4. A direction perpendicular to the plane of the spiral coil and an axis of the cylindrical shape of the solenoid coil are perpendicular to each other. The wireless power receiving device according to claim 1 .

5. The spiral coil includes a wound linear conductor and a magnetic sheet disposed parallel to the wound conductor. The wireless power receiving device according to claim 1 .

6. The solenoid coil includes a spiral linear conductor and a magnetic core disposed inside the spiral linear conductor. The wireless power receiving device according to claim 1 .

7. The frequency of the external magnetic field is 6.78 MHz or 13.56 MHz. The wireless power receiving device according to claim 1 .

8. a first resonant frequency of the first power receiving resonant circuit and a second resonant frequency of the second power receiving resonant circuit are the same; The wireless power receiving device according to claim 1 .

9. The load includes a secondary battery and a charge / discharge control circuit that controls charging of the secondary battery. The wireless power receiving device according to claim 1 .

10. The secondary battery is a thin battery. The wireless power receiving device according to claim 9 .

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