Short-range wireless communication device

Abstract

The short-distance wireless communication device (101) comprises: a communication antenna (11) for short-distance wireless communication, formed along a plane; an interface circuit (12) connected to the communication antenna (11) to pass the short-distance wireless communication signal; a wireless communication IC (NFC-IC (16)) connected to the interface circuit (12) to process the short-distance wireless communication signal; a power receiving coil (21L) arranged to surround the communication antenna (11) along the plane; a resonant capacitor (21C) forming a power receiving resonant circuit (21) together with the power receiving coil (21L); and a rectifying and smoothing circuit (22) connected to the power receiving resonant circuit (21). The power receiving resonant circuit (21) resonates at a frequency of short-distance wireless communication, and a magnetic flux generated near the power receiving coil (21L) by a resonant current flowing through the power receiving resonant circuit (21) interlinks with the communication antenna (11).

Description

Technical Field

[0001] The present invention relates to a short-distance wireless communication device with a wireless power receiving function. Background Art

[0002] Patent document 1 discloses a small non-contact charging module, which is a module having a non-contact charging coil, an NFC antenna, and a magnetic sheet, and is capable of communication and power transmission. Patent document 1 shows a non-contact charging module, which is provided with: a charging coil; an NFC coil arranged to surround the charging coil; a first magnetic sheet supporting the charging coil; and a second magnetic sheet placed on the first magnetic sheet and supporting the NFC coil.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 5013019 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The non-contact charging module described in Patent Document 1 is a module in which a coil for non-contact charging, a magnetic body for non-contact charging, a coil for NFC, and a magnetic body for NFC are integrated, and therefore it is easy to reduce the size when incorporated into a portable terminal.

[0008] However, in the contactless charging module described in Patent Document 1, the coil and magnetic body used for contactless charging and the coil and magnetic body used for NFC communication are substantially independent, and apart from the miniaturization of the structure, there is no organic connection in electrical and magnetic properties.

[0009] An object of the present invention is to provide a short-distance wireless communication device having a wireless power receiving function and having improved characteristics of short-distance wireless communication.

[0010] Technical solutions to solve problems

[0011] As an example of the present disclosure, a short-distance wireless communication device comprises: a communication antenna for short-distance wireless communication, arranged on a plane; an interface circuit, connected to the communication antenna, allowing the signal of the short-distance wireless communication to pass; a wireless communication IC, connected to the interface circuit, processing the signal of the short-distance wireless communication; a power receiving coil, arranged to surround the communication antenna along the plane; a resonant capacitor, which together with the power receiving coil constitutes a power receiving resonant circuit; and a rectifying and smoothing circuit, connected to the power receiving resonant circuit. Moreover, the power receiving resonant circuit resonates at the frequency of the short-distance wireless communication, and the magnetic flux generated near the power receiving coil by the resonant current flowing through the power receiving resonant circuit interlinks with the communication antenna.

[0012] According to the above configuration, the power receiving resonance circuit resonates at the frequency of the short-range wireless communication, and the magnetic flux generated in the vicinity of the power receiving coil by the resonance current flowing through the power receiving resonance circuit interlinks with the communication antenna, so that the power receiving coil can receive and receive the magnetic flux for transmitting the signal for the short-range wireless communication generated by the communication antenna on the other side, or can generate and send the magnetic flux for transmitting the signal for the short-range wireless communication in the vicinity of the power receiving coil.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to obtain a short-distance wireless communication device capable of increasing both the communication distance and the power transmission distance by using a power receiving resonance circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a plan view showing the structure of a communication antenna and a power receiving coil included in the short-distance wireless communication device according to the first embodiment.

[0016] Figure 2 It is a block diagram showing the configuration of a short-distance wireless communication system including the short-distance wireless communication device 101 according to the first embodiment.

[0017] Figure 3 It is a block diagram showing the configuration of a short-distance wireless communication system including the short-distance wireless communication device 101 according to the first embodiment.

[0018] Figure 4 1 is a diagram showing an example of a circuit configuration from the NFC-IC 16 of the short-range wireless communication device 101 to the communication antenna 11 .

[0019] Figure 5 It is shown Figure 3 FIG. 2 is a diagram showing an example of a configuration of a power transmission circuit 50 shown in FIG.

[0020] Figure 6 It is shown Figure 5FIG. 2 is a diagram showing an example of a circuit configuration of a power conversion circuit 52 and a rectifying and smoothing circuit 22.

[0021] Figure 7 2 is a diagram showing another configuration example of the rectifying and smoothing circuit 22 .

[0022] Figure 8 1 is a diagram showing the relationship between the coupling coefficients among the other-side communication antenna 41 , the communication antenna 11 , and the power receiving coil 21L.

[0023] Fig. 9 (A) Fig. 9 (B) is a diagram showing the configurations of the power receiving coil 21L and the communication antenna 11 for simulating the positional relationship between the power receiving coil 21L and the communication antenna 11 and the relationship between the coupling coefficient k12 therebetween.

[0024] Fig.10 It is shown that the communication antenna 11 is Fig. 9 As shown in (A), from the center of the power receiving coil 21L, Fig. 9 (B) is a diagram showing a change in the coupling coefficient k12 when moving along the diagonal line to the corner of the power receiving coil 21L.

[0025] Fig.11 It is a plan view showing the structure of a communication antenna and a power receiving coil included in the short-distance wireless communication device according to the second embodiment.

[0026] Fig.12 It is a plan view showing the structure of a communication antenna and a power receiving coil included in another short-distance wireless communication device according to the second embodiment.

[0027] Fig.13 It is a perspective view showing the structure of a communication antenna and a power receiving coil included in a short-distance wireless communication device according to a third embodiment.

[0028] Fig.14 It is shown Fig.13 A cross-sectional view of the structure of the communication antenna and the power receiving coil shown.

[0029] Fig.15 It is a perspective view showing the structure of a communication antenna and a power receiving coil included in another short-distance wireless communication device according to the third embodiment.

[0030] Fig.16 It is shown Fig.15 A cross-sectional view of the structure of the communication antenna and the power receiving coil shown. DETAILED DESCRIPTION

[0031] Hereinafter, a plurality of methods for implementing the present invention are illustrated with reference to the drawings and by enumerating several specific examples. In each figure, the same reference numerals are used to mark the same parts. In consideration of the ease of explanation or understanding of the key points, the embodiments are shown separately for convenience, but partial replacement or combination of the structures shown in different embodiments is possible. After the second embodiment, the description of matters common to the first embodiment is omitted, and only the differences are described. In particular, the same effects based on the same structure will not be mentioned one by one in each embodiment.

[0032] 《First Implementation Method》

[0033] Figure 1 FIG. 1 is a plan view showing the structure of a communication antenna and a power receiving coil included in the short-distance wireless communication device according to the first embodiment. Figure 1 In the embodiment, the communication antenna 11 is a communication antenna of NFC, and the power receiving coil 21L is a power receiving coil for wireless power receiving. The communication antenna 11 is arranged along a plane. In addition, the power receiving coil 21L is arranged to surround the communication antenna 11 along a plane. The communication antenna 11 is composed of a square spiral coil conductor wound with multiple turns. The power receiving coil 21L is also composed of a square spiral coil conductor wound with multiple turns.

[0034] The short-distance wireless communication device may include a magnetic body close to the communication antenna 11 and the power receiving coil 21L. The magnetic body forms a part of the magnetic path of the magnetic flux interlinked with the communication antenna 11 and the power receiving coil 21L. The magnetic body will be exemplified later.

[0035] Figure 1 The communication antenna 11 and the power receiving coil 21L shown are provided in a card-type electronic device of the size of a credit card, for example. That is, the short-range wireless communication device is configured as a card-type electronic device. In this case, Figure 1 The power receiving coil 21L shown is arranged along the outer shape of the card-type electronic device. When using the card-type electronic device, as shown later, NFC communication is performed by covering the communication antenna (communication antenna on the other side) of the NFC communication device. In addition, wireless power reception is performed by covering the power transmission coil of the power transmission device.

[0036] Figure 2 1 is a block diagram showing the structure of a short-distance wireless communication system including the short-distance wireless communication device 101 according to the first embodiment. Figure 2 In the state shown, the short-range wireless communication system includes a short-range wireless communication device 101 , a counterpart communication antenna 41 , and an NFC communication circuit 42 .

[0037] The short-range wireless communication device 101 includes a communication antenna 11 , an interface circuit 12 connected to the communication antenna 11 and allowing NFC communication signals to pass therethrough, and an NFC-IC 16 connected to the interface circuit 12 and processing the NFC communication signals.

[0038] The short-distance wireless communication device 101 also includes a power receiving coil 21L, a resonant capacitor 21C that forms a power receiving resonant circuit 21 together with the power receiving coil 21L, and a rectifying and smoothing circuit 22 connected to the power receiving resonant circuit 21 .

[0039] The short-distance wireless communication device 101 also includes a voltage conversion circuit 23 connected to the output portion of the rectifying and smoothing circuit 22 , a charging circuit 24 , a secondary battery 30 , a charging control circuit 25 , a discharge control circuit 14 , and a voltage conversion circuit 15 .

[0040] The voltage conversion circuit 23 is composed of, for example, a DC-DC converter, and converts the output voltage of the rectifying and smoothing circuit 22 into a voltage required by the charging circuit 24. The charging circuit 24 charges the secondary battery 30 using the output voltage of the voltage conversion circuit 23. The voltage conversion circuit 15 converts the electromotive force of the secondary battery 30 into a given voltage and supplies it to the NFC-IC 16 as a power supply voltage.

[0041] The charging control circuit 25 controls the validity / invalidity of the operation of the charging circuit 24 based on the control signal output from the NFC-IC 16. For example, the charging is stopped when the NFC communication is performed, and the charging is performed when the NFC communication is not performed.

[0042] The discharge control circuit 14 controls the validity / invalidity of the operation of the voltage conversion circuit 15 according to the control signal output from the NFC-IC 16. For example, the operation of the voltage conversion circuit 15 is enabled when NFC communication is performed, and the voltage conversion circuit 15 is disabled to stop the discharge when NFC communication is not performed.

[0043] exist Figure 2 In the state shown, the other party's communication antenna 41 and the communication antenna 11 for NFC communication are magnetically coupled, and NFC communication is performed through the NFC communication circuit 42 and the NFC-IC16. In addition, the other party's communication antenna 41 is also magnetically coupled with the power receiving coil 21L. The resonant frequency of the power receiving resonance circuit 21 is the frequency of the NFC communication signal, that is, the 13.56MHz frequency band. In addition, the impedance of the power receiving resonance circuit 21 at the frequency of the NFC communication signal is less than 1 / 2 of the impedance of the interface circuit 12 at the frequency of the NFC communication signal. Therefore, the power of the NFC communication signal can be received with high efficiency.

[0044] Figure 3 1 is a block diagram showing the structure of a short-distance wireless communication system including the short-distance wireless communication device 101 according to the first embodiment. Figure 3 In the state shown, the short-distance wireless communication system includes a short-distance wireless communication device 101, a power transmission circuit 50, and a power transmission resonance circuit 51. The power transmission resonance circuit 51 includes a power transmission coil 51L and a resonance capacitor 51C. The structure of the short-distance wireless communication device 101 is similar to Figure 2 The short-range wireless communication device 101 shown is the same. That is, Figure 3 The example shown is a state where the NFC device 101 is placed close to the power transmission coil 51L. In this state, the power transmission coil 51L and the power receiving coil 21L are magnetically coupled. The power receiving resonant circuit 21 is coupled with the power transmission resonant circuit 51 to perform magnetic resonance, and power is received from the power transmission circuit 50 to the power receiving circuit including the rectifying and smoothing circuit 22, the voltage conversion circuit 23, and the charging circuit 24.

[0045] exist Figure 3 In the state shown, the power transmission coil 51L is still magnetically coupled with the communication antenna 11, but the NFC-IC 16 does not perform NFC communication. In addition, in this state, the charging control circuit 25 does not receive a control signal from the NFC-IC 16, and the charging circuit becomes "valid". As a result, the secondary battery 30 is charged with the power wirelessly received from the power transmission circuit 50. Furthermore, the discharge control circuit 14 does not receive a control signal from the NFC-IC 16, and the voltage conversion circuit 15 becomes "invalid". As a result, useless discharge from the secondary battery 30 can be suppressed.

[0046] Figure 4 1 is a diagram showing an example of a circuit configuration from the NFC-IC 16 of the short-range wireless communication device 101 to the communication antenna 11. Figure 4 In the embodiment, the interface circuit 12 includes a matching circuit 12M, a transmission filter 12TF, and a reception filter 12RF. The NFC-IC 16 includes transmission signal terminals Tx1, Tx2, reception signal terminals Rx1, Rx2, and a ground terminal TVSS. The NFC-IC 16 performs modulation and demodulation between baseband signals and high-frequency signals. In addition, the NFC-IC 16 also performs input and output of data including communication data.

[0047] The transmission filter 12TF is an EMI removal filter including an inductor L0 and a capacitor C0, suppresses the release of noise generated by the NFC-IC 16 and the intrusion of noise into the NFC-IC 16, and passes the frequency band of the NFC transmission signal. The reception filter 12RF includes a capacitor C2b, which passes the NFC reception signal. The matching circuit 12M is a matching circuit including capacitors C1 and C2a, which matches the impedance of the NFC-IC 16 through the transmission filter 12TF and the impedance of the communication antenna 11.

[0048] Although in Figure 4 Although not shown in the figure, if a resistance component is provided in the circuit structure from NFC-IC16 to the communication antenna 11, the input impedance can be increased, and the release of noise generated by NFC-IC16 and the intrusion of noise into NFC-IC16 can be suppressed. On the other hand, the electric energy converted from the magnetic energy obtained by passing through the communication antenna 11 will be consumed as Joule heat due to the aforementioned resistance component. In contrast, for the power receiving resonance circuit connected to the power receiving coil, the resistance component is small enough, and the consumption of electric energy and magnetic energy is small. Therefore, the communication distance can be increased by the power receiving resonance circuit.

[0049] Figure 5 It is shown Figure 3 1 is a diagram showing a configuration example of a power transmission circuit 50. The power transmission circuit 50 includes a DC power supply 55, a voltage conversion circuit 53, a power conversion circuit 52, and a power control circuit 54. The voltage conversion circuit 53 converts the voltage of the DC power supply 55 into a voltage suitable for the power conversion circuit 52. The power conversion circuit 52 is controlled by the power control circuit 54 and supplies transmission power to the power transmission resonance circuit 51.

[0050] exist Figure 5 In the embodiment, the power transmission resonance circuit 51 includes a power transmission coil 51L and a resonance adjustment circuit 51A. The resonance adjustment circuit 51A is Figure 3 The resonance capacitor 51C shown in the figure. The resonance adjustment circuit 51A and the power transmission coil 51L constitute a resonance circuit, and the power reception coil 21L and the resonance adjustment circuit 21A constitute a power reception resonance circuit 21. The resonance adjustment circuit 21A is Figure 3 The resonant capacitor 21C etc. shown.

[0051] The above-mentioned power transmission resonance circuit 51 and the power receiving resonance circuit 21 resonate to perform electromagnetic field resonance. In this way, wireless power transmission is performed by the so-called DC resonance method. The resonance adjustment circuit 21A and the power receiving resonance circuit 21 connected to the power receiving coil 21L are not for communication purposes, so there is no need to suppress the resistance component of noise release and noise invasion, and the resistance component in the circuit structure can be fully reduced to reduce the input impedance. Therefore, the consumption of electric energy and magnetic energy is small. The electric energy converted from the magnetic energy obtained by passing through the power receiving coil 21L can be stored in the power receiving resonance circuit, which can increase the communication distance.

[0052] Figure 6 It is shown Figure 5 FIG. 5 is a diagram showing an example of a circuit configuration of a power conversion circuit 52 and a rectifying and smoothing circuit 22. The power conversion circuit 52 includes a switching element Q1, a diode D ds1 and capacitor C ds1 The first switch circuit S1 is composed of a parallel connection circuit of the switching element Q2 and the diode D ds2 and capacitor C ds2 The second switch circuit S2 is composed of a parallel connection circuit.

[0053] The switching elements Q1 and Q2 are controlled by the power control circuit 54 ( Figure 5 ) is switched. The switching element Q1 of the first switching circuit S1 and the switching element Q2 of the second switching circuit S2 are alternately turned on / off.

[0054] The switching elements Q1 and Q2 are switching elements such as MOSFETs having parasitic output capacitance and parasitic diodes, and the switching circuits S1 and S2 are formed by the parasitic output capacitance and the parasitic diodes.

[0055] The switch control circuit switches the first switch element Q1 and the second switch element Q2 at a given operating frequency, thereby intermittently supplying a DC voltage to the power transmission resonance mechanism to generate a resonant current in the power transmission resonance mechanism. As a result, the voltage across the first switch circuit S1 and the second switch circuit S2 is set to a half-wave sine wave waveform every half cycle. Specifically, the switching operation is performed at 13.56 MHz used in NFC communication.

[0056] The power receiving circuit includes a power receiving resonance circuit 21 formed by a power receiving coil 21L and a resonance capacitor 21C, and a rectification and smoothing circuit 22. The rectification and smoothing circuit 22 includes a diode D3 and a capacitor C ds3 The third switch circuit S3 is composed of a parallel connection circuit of the diode D4 and the capacitor C ds4 The fourth switch circuit S4 is composed of a parallel connection circuit.

[0057] The third switch circuit S3 and the fourth switch circuit S4 rectify the voltage generated in the power receiving resonance circuit 21 formed by the power receiving coil 21L and the resonance capacitor 21C. o This voltage is smoothed. In this example, the power receiving coil 21L and the resonant capacitor 21C constitute a series resonant circuit.

[0058] Figure 7 2 is a diagram showing another configuration example of the rectifying and smoothing circuit 22. In this way, the input of the diode bridge circuit DB may be connected to the power receiving resonance circuit 21, and a smoothing capacitor C may be connected to the output of the diode bridge circuit DB. o .

[0059] Figure 8 The figure shows the relationship between the coupling coefficients of the other party's communication antenna 41, the communication antenna 11, and the power receiving coil 21L. Here, if k1 represents the coupling coefficient between the other party's communication antenna 41 and the communication antenna 11, k2 represents the coupling coefficient between the other party's communication antenna 41 and the power receiving coil 21L, and k12 represents the coupling coefficient between the communication antenna 11 and the power receiving coil 21L, then the relationship of k12>k1 is achieved.

[0060] According to the above relationship, the communication antenna 11 is not only coupled to the other party's communication antenna 41, but also strongly coupled to the power receiving coil 21L. The power receiving coil 21L is also coupled to the other party's communication antenna 41, so the communication antenna 11 can perform NFC communication via the power receiving coil 21L. Therefore, a large communication signal can be obtained through the power receiving resonance circuit 21. Alternatively, the communication distance can be increased.

[0061] Fig. 9 (A) Fig. 9 (B) is a diagram showing the configuration of the power receiving coil 21L and the communication antenna 11 for simulating the positional relationship between the power receiving coil 21L and the communication antenna 11 and the relationship between the coupling coefficient k12 therebetween. The specifications of the communication antenna 11 and the power receiving coil 21L are as follows.

[0062] [Communication antenna 11]

[0063] Appearance: 8.4mm×8.4mm

[0064] Wiring width: 0.15mm

[0065] Wiring spacing: 0.2mm

[0066] Number of turns: 13

[0067] [Power receiving coil 21L]

[0068] Dimensions: 46mm×77mm

[0069] Wiring width: 0.8mm

[0070] Wiring spacing: 1.2mm

[0071] Number of turns: 2

[0072] Fig.10 It is shown that the communication antenna 11 is Fig. 9 As shown in (A), from the center of the power receiving coil 21L, Fig. 9 (B) is a diagram showing a change in the coupling coefficient k12 when moving along the diagonal line to the corner of the power receiving coil 21L.

[0073] Compared with the case where the communication antenna 11 is located at the center of the power receiving coil 21L, the coupling coefficient k12 between the communication antenna 11 and the power receiving coil 21L is improved when the communication antenna 11 is located along the edge. In particular, if the communication antenna 11 is located along the corner of the power receiving coil 21L, the communication antenna 11 will be close to the two sides of the power receiving coil 21L, so that the communication antenna 11 is located at the corner of the power receiving coil 21L. Fig.10 As shown, the closer to the corner (side), the more rapidly the coupling coefficient k12 between the communication antenna 11 and the power receiving coil 21L increases. In order to satisfy the above relationship of k12>k1, the communication antenna 11 is preferably arranged close to the side of the power receiving coil 21L.

[0074] <<Second Implementation Method>>

[0075] In the second embodiment, a short-distance wireless communication device including a magnetic body close to the communication antenna 11 and the power receiving coil 21L is shown.

[0076] Fig.11 FIG. 1 is a plan view showing the structure of a communication antenna and a power receiving coil included in a short-distance wireless communication device according to a second embodiment. Fig.11 In the embodiment, the communication antenna 11 is an NFC communication antenna, and the power receiving coil 21L is a power receiving coil for wireless power receiving. The communication antenna 11 is formed along a plane, and the power receiving coil 21L is arranged to surround the communication antenna 11 along the plane. Figure 1 Unlike the example shown in the figure, in this example, a power receiving coil magnetic sheet 62 is provided along the winding direction of the power receiving coil 21L. Fig.11 In the figure, the surface in the +Z direction is the side of the other party communication antenna 41 or the power transmission coil 51L. The power reception coil magnetic sheet 62 is formed by, for example, forming magnetic ferrite into a flexible sheet.

[0077] According to this configuration, the power receiving coil magnetic sheet 62 functions as a part of the magnetic path of the magnetic flux interlinking the power receiving coil 21L, so that the power receiving coil 21L and the counterpart communication antenna 41 ( Figure 2 ) of the coupling coefficient k2( Figure 8) or the power receiving coil 21L and the power transmitting coil 51L ( Figure 3 In addition, since the communication antenna 11 is close to the power receiving coil 21L, the power receiving coil magnetic sheet 62 functions as a part of the magnetic path of the magnetic flux that interlinks the power receiving coil 21L and the communication antenna 11, and thus the coupling coefficient k12 between the communication antenna 11 and the power receiving coil 21L is also improved.

[0078] Fig.12 FIG. 1 is a plan view showing the structure of a communication antenna and a power receiving coil included in another short-distance wireless communication device according to the second embodiment. Fig.12 In the embodiment, the communication antenna 11 is an NFC communication antenna, and the power receiving coil 21L is a power receiving coil for wireless power receiving. The communication antenna 11 is formed along a plane, and the power receiving coil 21L is arranged to surround the communication antenna 11 along the plane. Fig.11 The example shown is further different in that a communication antenna magnetic sheet 61 is provided at a position overlapping with the communication antenna 11. Fig.11 The surface in the +Z direction is the other party communication antenna 41 or the power transmission coil 51L side. The communication antenna magnetic sheet 61 is also formed by forming magnetic ferrite into a flexible sheet, for example, similarly to the power reception coil magnetic sheet 62.

[0079] According to this structure, in addition to Fig.11 In addition to the effects of the structure shown, the following effects are also achieved. First, the communication antenna magnetic sheet 61 functions as a part of the magnetic circuit of the magnetic flux that links the communication antenna 11, so that the communication antenna 11 and the other party's communication antenna 41 ( Figure 2 ) of the coupling coefficient k1( Figure 8 ) is improved. In addition, since the communication antenna magnetic sheet 61 and the power receiving coil magnetic sheet 62 are close to each other, the communication antenna magnetic sheet 61 and the power receiving coil magnetic sheet 62 function as a part of the magnetic path of the magnetic flux that interlinks the power receiving coil 21L and the communication antenna 11. As a result, the coupling coefficient k12 between the communication antenna 11 and the power receiving coil 21L is further improved.

[0080] Alternatively, the communication antenna magnetic sheet 61 and the power receiving coil magnetic sheet 62 may be formed as an integral body.

[0081] 《Third Implementation Method》

[0082] In the third embodiment, a short-distance wireless communication device is shown in which the structure of a magnetic body is different from the example shown in the second embodiment.

[0083] Fig.13 : is a perspective view showing the structure of a communication antenna and a power receiving coil included in a short-distance wireless communication device according to a third embodiment. Fig.142 is a cross-sectional view showing the structure of the communication antenna and the power receiving coil. In this example, there are a power receiving coil substrate 72 on which the power receiving coil 21L is formed, a magnetic sheet 62, a communication antenna substrate 71 on which the communication antenna 11 is formed, and a magnetic sheet 61. The power receiving coil magnetic sheet 62 overlaps with almost the entire surface of the power receiving coil substrate 72. In addition, the communication antenna magnetic sheet 61 overlaps with almost the entire surface of the communication antenna substrate 71. Moreover, the group of the communication antenna substrate 71 and the magnetic sheet 61 overlaps with the group of the power receiving coil substrate 72 and the power receiving coil magnetic sheet 62. The power receiving coil 21L is configured to surround the communication antenna 11 along the plane.

[0084] exist Fig.13 , Fig.14 In the example shown, the power receiving coil magnetic sheet 62 is present on the entire surface of the coil opening of the power receiving coil 21L, so that the power receiving coil 21L and the other party communication antenna 41 ( Figure 2 ) of the coupling coefficient k2( Figure 8 ) or the power receiving coil 21L and the power transmitting coil 51L ( Figure 3 ) is further improved. In addition, since there are more magnetic bodies between the power receiving coil 21L and the communication antenna 11, the coupling coefficient k12 between the communication antenna 11 and the power receiving coil 21L is further improved. In other words, even if the communication antenna 11 is located closer to the center than along the side or corner of the power receiving coil 21L, the coupling coefficient k12 between the communication antenna 11 and the power receiving coil 21L is effectively improved.

[0085] Fig.15 : is a perspective view showing the structure of a communication antenna and a power receiving coil included in another short-range wireless communication device according to the third embodiment. Fig.16 2 is a cross-sectional view showing the structure of the communication antenna and the power receiving coil. In this example, a substrate 70 and a magnetic sheet 60 are provided on which a power receiving coil 21L and a communication antenna 11 are formed. The magnetic sheet 60 overlaps almost the entire surface of the substrate 70. The power receiving coil 21L is formed to surround the communication antenna 11 along a plane.

[0086] exist Fig.15 , Fig.16 In the example shown, the magnetic sheet 60 is present on the entire surface of the coil opening of the power receiving coil 21L, so that the power receiving coil 21L and the other party communication antenna 41 ( Figure 2 ) of the coupling coefficient k2( Figure 8 ) or the power receiving coil 21L and the power transmitting coil 51L ( Figure 3 ) is further improved. In addition, since the magnetic body existing between the power receiving coil 21L and the communication antenna 11 increases, the coupling coefficient k12 between the communication antenna 11 and the power receiving coil 21L is also effectively improved.

[0087] Finally, the description of the above-mentioned embodiments is illustrative in all aspects and is not restrictive. For those skilled in the art, deformation and changes can be appropriately made. The scope of the present invention is not shown by the above-mentioned embodiments, but by the claims. Furthermore, the scope of the present invention includes changes made from the embodiments within the scope equivalent to the claims.

[0088] For example, the present invention is not limited to card-type electronic devices, but can be applied to various electronic devices such as portable telephone terminals such as smart phones and feature phones, wearable terminals such as smart watches and smart glasses, portable PCs such as notebook PCs and tablet PCs, information devices such as cameras, game consoles, toys, and information media such as IC tags and IC cards.

[0089] Description of Reference Numerals

[0090] C ds1 , C ds2 , C ds3 , C ds4 , C o : capacitor;

[0091] D3, D4, D ds1 , D ds2 :diode;

[0092] DB: diode bridge circuit;

[0093] Q1: 1st switch element;

[0094] Q2: the second switching element;

[0095] Rx1, Rx2: receiving signal terminals;

[0096] S1: 1st switch circuit;

[0097] S2: 2nd switch circuit;

[0098] S3: the third switch circuit;

[0099] S4: 4th switch circuit;

[0100] TVSS: ground terminal;

[0101] Tx1, Tx2: sending signal terminals;

[0102] 11: Communication antenna;

[0103] 12: Interface circuit;

[0104] 12M: matching circuit;

[0105] 12RF: receiving filter;

[0106] 12TF: transmit filter;

[0107] 14: Discharge control circuit;

[0108] 15: voltage conversion circuit;

[0109] 16: NFC-IC (wireless communication IC);

[0110] 21: Power receiving resonant circuit;

[0111] 21A: resonance adjustment circuit;

[0112] 21C: resonant capacitor;

[0113] 21L: receiving coil;

[0114] 22: Rectification and smoothing circuit;

[0115] 23: voltage conversion circuit;

[0116] 24: Charging circuit;

[0117] 25: Charging control circuit;

[0118] 30: Secondary battery;

[0119] 41: Communication antenna on the other side;

[0120] 42: NFC communication circuit;

[0121] 50: power transmission circuit;

[0122] 51: power transmission resonance circuit;

[0123] 51A: resonance adjustment circuit;

[0124] 51C: resonant capacitor;

[0125] 51L: power transmission coil;

[0126] 52: Power conversion circuit;

[0127] 53: voltage conversion circuit;

[0128] 54: power control circuit;

[0129] 55: DC power supply;

[0130] 60: Magnetic sheet;

[0131] 61: Communication antenna magnetic sheet;

[0132] 62: Magnetic sheet of receiving coil;

[0133] 70: substrate;

[0134] 71: Communication antenna substrate;

[0135] 72: receiving coil substrate;

[0136] 101: Short-range wireless communication device.

Claims

1. A short-range wireless communication device, characterized in that: have: A communication antenna for short-range wireless communication, arranged on a plane; An interface circuit connected to the communication antenna to allow the short-range wireless communication signal to pass through; A wireless communication IC, connected to the interface circuit, for processing the signal of the short-range wireless communication; a power receiving coil configured to surround the communication antenna along the plane; a resonant capacitor, which together with the power receiving coil forms a power receiving resonant circuit; as well as A rectifying and smoothing circuit is connected to the power receiving resonance circuit. The power receiving resonance circuit resonates at the frequency of the short-range wireless communication. The magnetic flux generated in the vicinity of the power receiving coil by the resonant current flowing through the power receiving resonant circuit interlinks with the communication antenna. The communication antenna performs the short-range wireless communication with a communication antenna on the other side with which the communication antenna communicates, via the power receiving coil.

2. The short-range wireless communication device according to claim 1, characterized in that: The impedance of the power receiving resonance circuit at the frequency of the near-field wireless communication is equal to or less than 1 / 2 of the impedance of the interface circuit at the frequency of the near-field wireless communication.

3. The short-range wireless communication device according to claim 1 or 2, characterized in that: The communication antenna and the power receiving coil each have a plurality of sides, and the communication antenna is arranged so that the sides are parallel to the power receiving coil.

4. The short-range wireless communication device according to claim 1 or 2, characterized in that: The communication antenna and the power receiving coil are arranged on the same plane.

5. The short-range wireless communication device according to claim 1 or 2, characterized in that: The communication antenna and the power receiving coil are stacked and arranged on different planes.

6. The short-range wireless communication device according to claim 5, characterized in that: The communication antenna is formed on a communication antenna substrate, and the power receiving coil is formed on a power receiving coil substrate. The communication antenna substrate and the power receiving coil substrate are stacked.

7. The short-range wireless communication device according to claim 6, characterized in that: The invention comprises a magnetic sheet which is laminated on the communication antenna substrate and the power receiving coil substrate and forms a part of a magnetic path of a magnetic flux interlinked with the communication antenna and the power receiving coil.

8. The short-range wireless communication device according to claim 7, characterized in that: The magnetic sheet is stacked between the communication antenna substrate and the power receiving coil substrate.

9. The short-range wireless communication device according to claim 1 or 2, characterized in that: The invention comprises a communication antenna magnetic sheet arranged close to the communication antenna and forming a part of a magnetic circuit for interlinking a magnetic flux generated by a current flowing through the power receiving coil with the communication antenna.

10. The short-range wireless communication device according to claim 1 or 2, characterized in that: The invention comprises a power receiving coil magnetic sheet arranged close to the power receiving coil and forming a part of a magnetic circuit for interlinking a magnetic flux generated by an external counterpart communication antenna with the power receiving coil.

11. The short-range wireless communication device according to claim 1 or 2, characterized in that: have: a secondary battery that functions as a power source for the wireless communication IC; and A charging circuit charges the secondary battery through the voltage of the rectifying and smoothing circuit.

12. The short-range wireless communication device according to claim 1 or 2, characterized in that: The coupling coefficient between the power receiving coil and the communication antenna is larger than the coupling coefficient between the power receiving coil and a power transmitting coil coupled to the power receiving coil.

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