Abstract:
The present disclosure provides an electronic component, including, a coil, and a circuit portion having a grounding terminal and a hot terminal and connected to the coil, wherein the grounding terminal of the circuit portion is connected to one end side of the coil, and the hot terminal of the circuit portion is connected to the other end side of the coil, thereby integrating the circuit portion with the coil.

Description:
BACKGROUND 
     The present disclosure relates to an electronic component in which a coil (inductor) and a circuit portion connected to the coil are integrated with each other, a power feeding apparatus for feeding an electric power in a non-contact (wireless) manner by using a wireless power feeding system, a power receiving apparatus for receiving an electric power in the wireless manner by using the wireless power feeding system, and a wireless power feeding system. 
     An electromagnetic induction system is known as a system for carrying out supply of an electric power in a non-contact (wireless) manner. 
     In addition, in recent years, a wireless power feeding and charging system using either a system called a magnetic field sympathetic resonance system utilizing an electromagnetic sympathetic resonance phenomenon, or a system called an electric wave type has attracted attention. 
     In the non-contact power feeding system as the electromagnetic induction system which has already been generally used at present, a power feeding source and a power feeding destination (electric power receiving side) need to hold a magnetic flux in common. Thus, for the purpose of efficiently feeding the electric power, the power feeding source and the power feeding destination need to be disposed in close proximity to each other. Also, axis alignment for the coupling between the power feeding source and the power feeding destination is also important. 
     On the other hand, the non-contact power feeding system using the electromagnetic sympathetic resonance phenomenon has advantages that it can feed the electric power at a distance as compared with the case of the electromagnetic induction system because of the principles of the electromagnetic sympathetic resonance phenomenon, and even when the axis adjustment is poor a little, the feeding efficiency is not reduced so much. 
     It is noted that an electric field sympathetic resonance system using the electromagnetic sympathetic resonance phenomenon is known in addition to the magnetic field sympathetic resonance system using the electromagnetic sympathetic resonance phenomenon. 
     In the wireless power feeding system of the magnetic field sympathetic resonance type, the axis alignment is unnecessary, and it is possible to lengthen the power feeding distance. 
     Now, not only in the non-contact power feeding system, but also in an electronic apparatus including a coil, a capacitor, a composite electronic component, and the like, an integrated combination of a coil and a circuit portion is carried out. 
     Japanese Patent Nos. 3,377,756 and 3,377,787 disclose a technique with which in order to reduce a parasitic capacitance between an analog circuit portion and a coil when a circuit portion and a coil for communication are disposed close to each other, the circuit portion and the coil for communication are disposed so as not to overlap each other. 
     In addition, Japanese Patent Laid-Open No. Hei 6-124850 discloses a method of integrating a circuit, a multi-layer capacitor, and a coil with one another. With this method, a laminated body element and a circuit board which were manufactured separately from each other are joined to each other by using an adhesive agent, thereby realizing a multi-layer composite electronic component which is excellent in temperature characteristics. 
     SUMMARY 
     However, in the case of the technique disclosed in Japanese Patent Nos. 3,377,756 and 3,377,787, since the circuit portion and the coil for communication exist separately from each other, it becomes important that for the purpose of reducing an influence of the floating capacitance, the circuit portion and the coil for communication are physically disposed away from each other. 
     That is to say, the reduction of the influence described above causes a problem that the entire size becomes large. 
     In addition, in the case of the technique as well described in Japanese Patent Laid-Open No. Hei 6-124850, the coil, the capacitor portion, and the circuit portion are basically manufactured separately from one another, and are disposed close to one another by using the adhesive agent. 
     In a word, the technique described in Japanese Patent Laid-Open No. Hei 6-124850 dose not also solve the problem that the interference between the circuit and the coil which is set forth as the problem in Japanese Patent Nos. 3,377,756 and 3,377,787. 
     The present disclosure has been made in order to solve the problems described above, and it is therefore desirable to provide an electronic component, a power feeding apparatus, a power receiving apparatus, and a wireless power feeding system in each of which an entire size can be reduced because characteristics deterioration due to a floating capacitance, an eddy-current loss, and the like can be prevented from being caused when a circuit portion and a coil are disposed close to each other and thus the circuit portion and the coil can be integrated with each other. 
     In order to attain the desire described above, according to an embodiment of the present disclosure, there is provided an electronic component including: a coil; and a circuit portion having a grounding terminal and a hot terminal and connected to the coil, in which the grounding terminal of the circuit portion is connected to one end side of the coil, and the hot terminal of the circuit portion is connected to the other end side of the coil, thereby integrating the circuit portion with the coil. 
     According to another embodiment of the present disclosure, there is provided a power feeding apparatus including: a power transmitting side coil portion having a coil adapted to transmit an electric power in a wireless manner; a converter converting an AC electric power into a DC electric power; and a power transmitting circuit receiving the DC electric power obtained through the conversion in the converter, and generating a high-frequency electric power for wireless power transmission, thereby supplying the resulting high-frequency electric power to the power transmitting side coil portion, in which a circuit portion having a grounding terminal and a hot terminal, connected to the coil, and having sympathetic the power transmitting circuit and sympathetic the converter is formed; and the grounding terminal of the circuit portion is connected to one end side of the coil, and the hot terminal of the circuit portion is connected to the other end side of the coil, thereby integrating the circuit portion with the coil. 
     According to still another embodiment of the present disclosure, there is provided a power receiving apparatus including: a power receiving side coil portion having a coil receiving an electric power transmitted in a wireless manner; a rectifying circuit rectifying the electric power received by the power receiving side coil portion; and a power source circuit stabilizing the electric power obtained through rectification in the rectifier circuit, and supplying the electric power thus stabilized to a load, in which a circuit portion having a grounding terminal and a hot terminal, connected to the coil, and having at least the rectifying circuit and the power source circuit is formed; and the grounding terminal of the circuit portion is connected to one end side of the coil, and the hot terminal of the circuit portion is connected to the other end side of the coil, thereby integrating the circuit portion with the coil. 
     According to yet another embodiment of the present disclosure, there is provided a wireless power feeding system including: a power feeding apparatus; and a power receiving apparatus receiving an electric power transmitted from the power feeding apparatus with a magnetic field sympathetic resonance relationship, in which the power feeding apparatus includes: a power transmitting side coil having a coil adapted to transmit an electric power in a wireless manner; a converter converting an AC electric power into a DC electric power; and a power transmitting circuit receiving the DC electric power obtained through the conversion in the converter, and generating a high-frequency electric power for wireless power transmission, thereby supplying the resulting high-frequency electric power to the power transmitting side coil portion; the power receiving apparatus includes: a power receiving side coil portion having a coil receiving an electric power transmitted in a wireless manner; a rectifying circuit rectifying the electric power received by the power receiving side coil portion; and a power source circuit stabilizing the electric power obtained through the rectification in the rectifier circuit, and supplying the electric power thus stabilized to a load, in which at least one of the power feeding apparatus and the power receiving apparatus includes a circuit portion having a grounding terminal and a hot terminal, the grounding terminal is connected to one end side of the coil and the hot terminal is connected to the other end side of the coil, thereby integrating the circuit portion with the coil. 
     As set forth hereinabove, according to the present disclosure, since the characteristics deterioration due to the floating capacitance, the eddy-current loss, and the like can be prevented from being caused when the circuit portion and the coil are disposed close to each other, and the circuit portion and the coil can be integrated with each other, the entire size can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing an entire configuration of a wireless power feeding system according to an embodiment of the present disclosure; 
         FIG. 2  is a view schematically showing a basic relationship between a power transmitting side coil and a power receiving side coil of the wireless power feeding system according to the embodiment of the present disclosure; 
         FIG. 3  is a view schematically showing an example of a configuration of an integrated combination of the power transmitting side coil and a power transmitting system circuit portion in the embodiment of the present disclosure; 
         FIG. 4  is a view schematically showing a connection state between a coil pattern and the power transmitting system circuit portion of a power feeding apparatus of the wireless power feeding system according to the embodiment of the present disclosure; 
         FIG. 5  is a view showing a situation in which an image current when a metallic plate is located in the vicinity of a coil is caused to flow; 
         FIG. 6  is a view showing a configuration of an actual wireless charging (power feeding) system; 
         FIG. 7  is a view explaining an example of a calculation of an inductance value described in a design guide; 
         FIG. 8  is a circuit diagram showing a basic configuration of a resonance circuit composed of an inductor and a capacitor; 
         FIG. 9  is a view showing a situation of a distribution of a high-frequency current when the power feeding apparatus of the wireless power feeding system according to the embodiment of the present disclosure is driven; 
         FIG. 10  is a block diagram showing a configuration in which an insulated DC/DC converter is inserted into a circuit portion in the wireless power feeding system according to the embodiment of the present disclosure; 
         FIG. 11  is a block diagram, partly in circuit, showing a configuration of the insulated DC/DC converter; 
         FIG. 12  is a block diagram showing a configuration in which an insulated AC/DC converter is inserted into a circuit portion in the wireless power feeding system according to the embodiment of the present disclosure; 
         FIG. 13  is a block diagram showing a connection relationship between a shield case and a coil of a primary side circuit portion when the configuration shown in  FIG. 10  is adopted; 
         FIG. 14  is a block diagram concretely showing a connection relationship between the shield case and the coil of a primary side circuit portion shown in  FIG. 13 ; 
         FIG. 15  is a block diagram schematically showing a configuration of an integrated combination of a power receiving side coil and a power receiving system circuit portion in the embodiment of the present disclosure; 
         FIG. 16  is a perspective view schematically showing a connection state between a coil pattern and a circuit portion of a power receiving apparatus of the wireless power feeding system according to the embodiment of the present disclosure; 
         FIG. 17  is a circuit diagram, partly in block, showing a connection relationship between a shield case and a coil of a secondary side circuit portion when the configuration shown in  FIG. 15  is adopted; and 
         FIG. 18  is a circuit diagram, partly in block, concretely showing the connection relationship between the shield case and the coil of the secondary side circuit portion shown in  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present disclosure will be described in detail hereinafter with reference to the accompanying drawings. 
     It is noted that the description will be given below in accordance with the following order: 
     1. Basic Configuration of Wireless Power Feeding System; 
     2. Integrated Configuration of Power Transmitting Side Coil and Power Transmitting System Circuit Portion; and 
     3. Integrated Configuration of Power Receiving Side Coil and Power Receiving System Circuit Portion. 
     1. Basic Configuration of Wireless Power Feeding System 
       FIG. 1  is a block diagram showing an entire configuration of a wireless power feeding system according to an embodiment of the present disclosure. 
       FIG. 2  is a view schematically showing a basic relationship between a power transmitting side coil and a power receiving side coil of the wireless power feeding system according to the embodiment of the present disclosure. 
     The wireless power feeding system  10  includes a power feeding apparatus  20  as a primary side apparatus, and a power receiving apparatus  30  as a secondary side apparatus. 
     The power feeding apparatus  20  includes a power transmitting side coil portion  21  which can transmit (feed) an electric power in a wireless manner, a power transmitting circuit  22 , a converter  23 , and an AC cable portion  24 . 
     It is noted that in the embodiment of the present disclosure, as will be described later, a power transmitting system circuit portion  25  is composed of the power transmitting circuit  22  and the converter  23 , and has a configuration of being integrated with a coil of the power transmitting side coil portion  21 . 
     The power transmitting side coil portion  21  includes a sympathetic resonance coil  211  as a sympathetic resonance element. Although the sympathetic resonance coil is referred to as the resonance coil as well, in the embodiment, the term of the sympathetic resonance coil is adopted. 
     In addition, the power transmitting side coil portion  21  is provided with a power feeding coil as a power feeding element in some cases. 
     A high-frequency electric power for wireless electric power transmission is supplied from the power transmitting circuit  22  to the sympathetic resonance coil  211 . 
     When the sympathetic resonance coil  211  agrees in self-resonant frequency with a sympathetic resonance coil  311  of the power receiving apparatus  30 , the sympathetic resonance coil  211 , and the sympathetic resonance coil  311  show a magnetic field sympathetic resonance relationship. As a result, the electric power is efficiently transmitted. 
     The power transmitting circuit  22  generates a high-frequency electric power for wireless electric power transmission. 
     Since the power transmitting circuit  22  preferably generates the high-frequency electric power with high efficiency, a switching amplifier or the like is used as the power transmitting circuit  22 . 
     The high-frequency electric power generated in the power transmitting circuit  22  is fed (applied) to the sympathetic resonance coil  211  of the power transmitting coil portion  21  through an impedance detector, a matching circuit and the like (not shown). 
     The converter  23  converts an AC electric power into a DC electric power, and supplies the resulting DC electric power to the power transmitting circuit  22 . 
     As will be described later, the converter  23  is configured so as to include an AC/DC converter and a DC/DC converter. 
     The power receiving apparatus  30  is configured so as to include a power receiving side coil portion  31 , a rectifying circuit  32 , a power source circuit (voltage stabilizing circuit)  33 , and a battery (secondary battery)  34  as a load. 
     The power receiving apparatus  30  is equipped with the secondary battery  34  as the load such as a mobile phone. 
     It is noted that in the embodiment, as will be described later, a power receiving system circuit portion  35  is composed of the rectifying circuit  32  and the power source circuit  33 , and has a configuration of being integrated with a coil of the power receiving side coil portion  31 . 
     The power receiving side coil portion  31  includes a resonance (sympathetic resonance) coil  311  as a sympathetic resonance element. 
     In addition, the power receiving side coil portion  31  is provided with a power feeding coil to which an AC is fed from the sympathetic resonance coil  311  by the electromagnetic induction in some cases. 
     When the sympathetic resonance coil  311  agrees in self-resonant frequency with the sympathetic resonance coil  211  of the power feeding apparatus  20 , the sympathetic resonance coil  311  and the sympathetic resonance coil  211  show a magnetic field sympathetic resonance relationship. As a result, the electric power is received with high efficiency. 
     The rectifying circuit  32  rectifies the AC electric power received into a DC electric power and supplies the resulting DC electric power to the power source circuit  33 . 
     The power source circuit  33  converts the DC electric power supplied thereto from the rectifying circuit  32  into a stabilized DC voltage complying with a specification of an electronic apparatus as an electric power supply destination, and supplies the resulting stabilized DC voltage to the secondary battery  34  as the load as the electronic apparatus. 
     2. Integrated Configuration of Power Transmitting Side Coil and Power Transmitting System Circuit Portion 
       FIG. 3  is a view schematically showing an example of a configuration of an integrated combination of a power transmitting side coil and a power transmitting system circuit portion in the wireless power feeding system according to the embodiment of the present disclosure. 
       FIG. 4  is a view schematically showing a connection state between a coil pattern and the power transmitting system circuit portion of a power feeding apparatus of the wireless power feeding system according to the embodiment of the present disclosure. 
     As will be described below, in the embodiment, the coil  211  of the power feeding apparatus  20 , and the power transmitting system circuit portion  25  including the power transmitting circuit  22  and the converter  23  are formed integrally with each other. 
     Basically, a portion at a grounding (GND) potential of the power transmitting system circuit portion  25  is electrically connected to a pattern of the coil  211 . Thus, the power transmitting system circuit portion  25  functions as one element for determining an inductance value of the coil  211 . 
     The power transmitting system circuit portion  25  is shielded and thus a shield structure functions as one element for determining the inductance value of the coil  211 . 
     The coil  211  has a structure of making resonance at a desired resonant frequency fo, and thus either the circuit portion or the shield structure functions as one element for determining the resonant frequency fo. 
     A floating capacitance component of the coil, the capacitance of the capacitor element, or the like is used as a capacitance composing this resonance at this time. 
     In addition, the shield case also plays a role of a function as a radiator. 
     As has been described, in the embodiment, the coil  211  of the power feeding apparatus  20 , and the power transmitting system circuit portion  25  including the power transmitting circuit  22  and the converter  23  are formed integrally with each other. Here, the reason why this configuration of the integrated combination is adopted will be described below. 
     In the electromagnetic induction or magnetic field sympathetic resonance type wireless power feeding system, the magnetic field mainly carries out the exchange of the electric power. The coil is generally used in order to carry out transmission/reception of the electric power through the magnetic field. An electric power transmission efficiency η between coils is expressed by Expression (1):
 
η= k×Q   (1)
 
     where k is a coupling coefficient, and Q is a no-load Q of the coil. 
     One of the causes for reducing the coupling coefficient, k, and the no-load, Q, of the coil is characteristics deterioration due to a near metal. 
       FIG. 5  is a view showing a situation in which an image current when a metallic plate is located in the vicinity of a coil is caused to flow. 
     As shown in  FIG. 5 , when the metallic plate MP is disposed close to the coil CL, a circumferential electromagnetic field distribution acts like an image current IMI is equivalently caused to flow. The magnetic field formed by the image current IMI cancels a magnetic field formed by a current which is actually caused to flow through the coil CL, which reduces the Q value of the coil CL. In addition, at this time, since a large current (eddy-current) is caused to flow on the metallic plate MP, a conductor loss is caused to become a loss. 
     For example, when a wireless power feeding (charging) system is considered, a configuration thereof comes to be as shown in  FIG. 1 , and the power transmitting circuit  22 , and the converter  23  such as an AC/DC converter circuit are necessary for the power transmitting coil side. 
     The rectifying circuit  32 , the power source circuit  33 , the secondary battery (battery)  34 , and the like are necessary for the power receiving coil side as well. 
     Since these circuit portions are made of many metallic materials, the power feeding characteristics are largely deteriorated in some cases when these circuit portions are each disposed in the vicinity of the coil. 
       FIG. 6  is a view showing a configuration of an actual wireless charging (power feeding) system. 
     When the usability for a user is taken into consideration, preferably, the power feeding apparatus  20  as the primary side apparatus has a suitable area, and a portable electronic apparatus becoming the secondary side is freely placed on a planar surface of the power feeding apparatus  20 . In addition, since the secondary coil  311  is preferably disposed inside a projected area of the primary side coil, the primary side coil  211  is desirably wound around the entire surface of the primary side apparatus. 
     For the purpose of miniaturizing a size of the entire power feeding apparatus  20  as the primary side apparatus, it is expected that the power transmitting system circuit portion  25  is placed below the primary side coil. However, at this time, there is the possibility that since the metal of the power transmitting system circuit portion  25  is close to the coil  211 , the coil characteristics are reduced, and as a result, the power feeding characteristics are reduced. 
     In order to cope with such a situation, in the embodiment, in the power feeding apparatus  20 , as shown in  FIGS. 3 and 4 , the power transmitting system circuit portion  25  is configured so as to be integrated with the coil  211 . 
     For example, the coil  211  is formed into a spiral pattern PTN 1  on a board  26 , and the power transmitting system circuit portion  25  is also formed into a pattern PTN 2  on the same board  26  similarly to the case of the coil  211 . 
     The power transmitting system circuit portion  25  is accommodated in a shield case  251 . 
     Also, a portion at the grounding (GND) potential of the power transmitting system circuit portion  25  is provided in the form of the pattern PTN 2  so as to extend to the outside of the shield case  251 . Also, the pattern PTN 2  is electrically connected to one end side (inner circumference side end portion) of the spiral pattern PTN 1  of the coil  211 . In addition, a power feeding terminal (hot terminal)  252  of the power transmitting system circuit portion  25  is connected to the other end (outer circumference side end portion) of the spiral pattern PTN 1  of the coil  211 . 
     Since a large high-frequency current is caused to flow on the coil  211 , a loss needs to be reduced as much as possible. For this reason, the power transmitting system circuit portion  25  is preferably covered with the shield case  251 . The shield case  251  is made of a metallic member, such as aluminum, which functions as an electric field shielding portion. 
     In this case, a power feeding portion of the power feeding apparatus  20  comes to be as shown in  FIG. 4 . 
     In addition, since the power transmitting system circuit portion  25  is integrated with the coil  211 , a high-frequency current is caused to flow through the ground GND of the power transmitting system circuit portion  25 . 
     The high-frequency current is caused to flow through the shield case  251  as a shield portion which covers the power transmitting system circuit portion  25 . However, when a thickness of the shield metal is small, the high-frequency current leaks to the inside of the shield case  251  to cause the characteristics reduction. 
     A high-frequency current is mainly caused to flow through a surface of a metal. Thus, the high-frequency current is reduced as a depth of the metal the inside of which the high-frequency current enters is larger. A depth at which a current becomes 37/100 times smaller than that of a surface current is referred to as a skin depth. The skin depth δ is expressed by Expression (2): 
     Expression (2):
 
δ=√(2/σωμ)  (2)
 
     where σ is a conductivity, μ is a permeability, and ω is an angular frequency. 
     Therefore, preferably, the metal of each of the metallic shield and the circuit pattern has a thickness which is several times as large as the skin depth. 
     Also, in the embodiment, as described above, basically, the portion at the grounding (GND) potential of the power transmitting system circuit portion  25  is electrically connected to the pattern of the coil  211 . Thus, the power transmitting system circuit portion  25  functions as one element for determining an inductance value of the coil  211 . 
     A description will now be given with respect to the fact that the power transmitting system circuit portion  25  functions as one element for determining the inductance value of the coil  211  in the manner as described above. 
       FIG. 7  is a view explaining an example of a calculation of an inductance value described in a design guide. 
       FIG. 8  is a circuit diagram showing a basic configuration of a resonance circuit composed of an inductor and a capacitor. 
       FIG. 7  shows an example of a calculation for an inductance value described in a design guide presented by Microchip Technology Inc. 
     As expressed in Expression (3), an inductance value L depends on a long side lb, a short side la, and a line width a: 
     Expression (3) 
     
       
         
           
             
               
                 
                   L 
                   = 
                   
                     4 
                     ⁢ 
                     
                       { 
                       
                         
                           
                             l 
                             b 
                           
                           ⁢ 
                           
                             ln 
                             ⁡ 
                             
                               ( 
                               
                                 
                                   2 
                                   ⁢ 
                                   A 
                                 
                                 
                                   a 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       
                                         l 
                                         b 
                                       
                                       + 
                                       
                                         l 
                                         c 
                                       
                                     
                                     ) 
                                   
                                 
                               
                               ) 
                             
                           
                         
                         + 
                         
                           
                             l 
                             a 
                           
                           ⁢ 
                           
                             ln 
                             ⁡ 
                             
                               ( 
                               
                                 
                                   2 
                                   ⁢ 
                                   A 
                                 
                                 
                                   a 
                                   ⁡ 
                                   
                                     ( 
                                     
                                       
                                         l 
                                         a 
                                       
                                       + 
                                       
                                         l 
                                         c 
                                       
                                     
                                     ) 
                                   
                                 
                               
                               ) 
                             
                           
                         
                         + 
                         
                           2 
                           ⁡ 
                           
                             [ 
                             
                               a 
                               + 
                               
                                 l 
                                 c 
                               
                               - 
                               
                                 ( 
                                 
                                   
                                     l 
                                     a 
                                   
                                   + 
                                   
                                     l 
                                     b 
                                   
                                 
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                             ] 
                           
                         
                       
                       } 
                     
                     ⁢ 
                     
                       ( 
                       nH 
                       ) 
                     
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     Now, lc and A in Expression (3) are expressed by Expression (4): 
     Expression (4)
 
 lc= √{square root over (l a   2   +l   b   2 )}
 
 A=l   a   ×l   b   (4)
 
     In Expressions (3) and (4), each of units is cm. 
     When the power transmitting system circuit portion  25  is disposed on the coil  211  by using a method utilized in the embodiment of the present disclosure, it is understood that the short side, la, the long side, lb, and the line width, a, are influenced by the power transmitting system circuit portion  25 , that is, the physical structure of the power transmitting system circuit portion  25  becomes one element for determining the inductance value. 
     In this case, one winding of rectangular loop coil is given as an example. However, even in the case of plural windings of rectangular loop or circular loop, similarly, the power transmitting system circuit portion (circuit block)  25  is disposed on the coil, whereby the physical structure of the power transmitting system circuit portion  25  becomes one element for determining the inductance value L. 
     In addition, when a resonance circuit  40  is configured by using an inductance L and a capacitance C as shown in  FIG. 8 , the resonant frequency fo is obtained from ½π√LC. 
     That is to say, it can be said that the physical structure of the power transmitting system circuit portion  25  disposed on the coil  211  is one element for determining the inductance value L, and is also one element for determining the resonant frequency fo. 
     By the way, the floating capacitance component which the coil itself has, a capacitance of an external capacitor, or the like is used as the capacitance C. 
     Here, let us consider a distribution of the high-frequency current when the power feeding apparatus in the embodiment is driven. 
       FIG. 9  is a view showing a situation of a distribution of a high-frequency current when the power feeding apparatus of the wireless power feeding system according to the embodiment of the present disclosure is driven. 
     Ideally, as indicated by arrows X in  FIG. 9 , the high-frequency current is caused to flow only through the coil portion (including the circuit portion integrated with the coil portion). 
     However, a power source line  27  needs to be wired outside the power transmitting system circuit portion  25 . Thus, since the power source line  27  is electrically connected to the power transmitting system circuit portion  25 , as indicated by arrows Y in  FIG. 9 , an undesirable current is induced in the power source line  27  as well. 
     The undesirable high-frequency current generates an unintended radiation electromagnetic field. As a result, a problem about a bad influence exerted on the power feeding characteristics or the circumferential apparatus, or the like is feared. 
       FIG. 10  is a block diagram showing a configuration in which an insulated DC/DC converter is inserted into the power transmitting system circuit pattern in the wireless power feeding system according to the embodiment of the present disclosure. 
       FIG. 11  is a block diagram, partly in circuit, showing a configuration of the insulated DC/DC converter. 
     The insulated DC/DC converter  28  shown in  FIG. 11  includes an input filter  281 , an inverter  282 , an output transformer  283 , a rectifying circuit  284 , and a smoothing circuit  285 . In addition, the insulated DC/DC converter  28  includes a control portion  286 , a photocoupler  287 , and a drive circuit  288  as a feedback control system. 
     In this case, the insulated DC/DC converter  28  is included in a power transmitting system circuit portion  25 A and is connected to an AC/DC converter  29  in the outside of the power transmitting system circuit portion  25 A through the power source line  27 . 
     With regard to a method of improving the problem about the influence by the radiation electromagnetic field due to the undesirable high-frequency current, for example, as shown in  FIG. 10 , it is possible to adopt a method of inserting the insulated DC/DC converter  28  between the primary side apparatus and the power source line  27  extending from the primary side apparatus to the outside. 
     As shown in  FIG. 11 , the insulated DC/DC converter has an insulation configuration by interposing the output transformer  283  in the middle of the circuit of the insulated DC/DC converter. In a word, adoption of the insulation configuration prevents the high-frequency current from leaking to the external power source line  27 . 
       FIG. 12  is a block diagram showing a configuration in which an insulated AC/DC converter is inserted into a power transmitting system circuit portion in the wireless power feeding system according to the embodiment of the present disclosure. 
     As shown in  FIG. 12 , the insulated AC/DC converter  29 B can be adopted instead of adopting the insulated DC/DC converter  28 . 
     In such a manner, the AC/DC converter  29  is made to be of the insulation type, and the AC/DC converter  29 B is installed in a power transmitting system circuit portion  25 B provided inside the primary side apparatus. 
     In the case of the insulated AC/DC converter  29 B as well, since the insulation by the transformer is carried out inside the insulated AC/DC converter  29 B, the high-frequency current can be prevented from leaking to the outside. 
       FIG. 13  is a block diagram showing a connection relationship between a shield case and a coil of a primary side circuit portion when the configuration shown in  FIG. 10  is adopted. 
       FIG. 14  is a block diagram concretely showing a connection relationship between the shield case and the coil of the primary side circuit portion shown in  FIG. 13 . 
     In the case of  FIG. 14 , the power transmitting circuit  22  includes an electric power generating circuit  221 , and an impedance matching circuit  222 . In this case, the electric power generating circuit  221  receives a DC electric power from the insulated DC/DC converter  28 , and generates an electric power to be transmitted. Also, the impedance matching circuit  222  carries out impedance matching for the power feeding apparatus. 
     An output terminal of the power transmitting circuit  22  is connected as a hot terminal  252  to the outer circumference side end portion of the coil pattern PTN 1 , and a grounding GND terminal thereof is connected to the shield case  251 . 
     A portion at the grounding (GND) potential of the circuit portion  25  extends as the pattern PTN 2  to the outside of the shield case  251 . Also, the pattern PTN 2  is electrically connected to one end side (inner circumference side end portion) of the spiral pattern PTN 1  of the coil  211 . 
     A terminal (+) and a terminal (−) of the insulated DC/DC converter  28  are connected to the AC/DC converter  29  provided outside the power transmitting system circuit portion  25 A through the power source line  27 . 
     3. Integrated Configuration of Power Receiving Side Coil and Power Receiving System Circuit Portion 
       FIG. 15  is a block diagram schematically showing a configuration of an integrated combination of a power receiving side coil and a power receiving system circuit portion in the embodiment of the present disclosure. 
       FIG. 16  is a perspective view schematically showing a connection state between a coil pattern of a circuit portion of a power receiving apparatus of the wireless power feeding system according to the embodiment of the present disclosure. 
     As described above, there was shown the configuration in which the primary side coil  211  of the wireless power feeding (charging) system was integrated with the primary side power transmitting system circuit portion  25 . Likewise, there is shown a configuration in which the secondary side coil  311  is integrated with the secondary side circuit portion  35 . 
     In the embodiment, in the power receiving apparatus  30 C, as shown in  FIGS. 15 and 16 , a configuration is adopted in which a circuit portion  35  is integrated with a coil  311 . 
     For example, the coil  311  is formed into a spiral pattern PTN 11  on a board, and the circuit portion  35  is also formed into a pattern PTN 12  on the same board similarly to the case of the coil  311 . 
     The circuit portion  35  is accommodated in a shield case  351 . 
     Also, a portion at the grounding (GND) potential of the circuit portion  35  is provided in the form of the pattern PTN 12  so as to extend to the outside of the shield case  351 . Also, the pattern PTN 12  is electrically connected to one end side (inner circumference side end portion) of the spiral pattern PTN 11  of the coil  311 . In addition, a power feeding terminal (hot terminal) of the circuit portion  35  is connected to the other end (outer circumference side end portion) of the spiral pattern PTN 11  of the coil  311 . 
       FIG. 17  is a circuit diagram, partly in block, showing a connection relationship between the shield case and the coil of the secondary side circuit portion when the configuration shown in  FIG. 15  is adopted. 
       FIG. 18  is a circuit diagram, partly in block, concretely showing the connection relationship between the shield case and the coil of the secondary side circuit portion shown in  FIG. 17 . 
     In the cases of  FIGS. 17 and 18 , a matching circuit  36  is connected between the coil  311  and the rectifying circuit  32 . 
     As described above, in the power receiving apparatus  30  as well, a configuration is adopted in which the power receiving side circuit portion  30  is also integrated with the coil  311 . 
     Since a portable electronic apparatus is supposed in the case of the secondary side apparatus shown here, the power source line or the like is not basically wired to the outside of the secondary side apparatus. Therefore, for example, the influence due to leakage of the high-frequency current to the outside of the secondary side apparatus needs not to be taken into consideration. 
     One terminal of the matching circuit  32  of the power receiving circuit is connected as a hot terminal  352  to an outer circumference side end portion of the coil pattern PTN 11 , and a grounding GND terminal thereof is connected to the shield case  351 . 
     A portion at the grounding (GND) potential of the circuit portion  35  is provided in the form of the pattern PTN 12  so as to extend to the outside of the shield case  351 . Also, the pattern PTN 12  is electrically connected to one end side (inner circumference side end portion) of the spiral pattern PTN 11  of the coil  311 . 
     A terminal (+) and a terminal (−) of the power source circuit  33  are connected to a main board  37  to which a power source control circuit and the like of a receiving apparatus (power receiving apparatus)  30  are mounted. 
     As has been described, in the power receiving apparatus  30  as well, the coil  311  and the shield case  351  are connected to each other. Since each of drawing lines  38  from the secondary side circuit portion  35  is different in electric potential from the shield case  351 , these drawing lines  38  are insulated from the shield case  351 . 
     As has been described, according to the embodiment, the coils of the power feeding apparatus  20  and the power receiving apparatus  30  are formed so as to be integrated with the circuit portion. 
     Basically, the portion at the grounding (GND) potential of the circuit portion is electrically connected to the pattern of the coil, and thus the circuit portion functions as one element for determining the inductance value of the coil. 
     The circuit portion is shielded, and thus the shield structure functions as one element for determining the inductance value of the coil. 
     The coil is structured so as to resonate with the capacitance at the desired resonant frequency fo, and thus either the circuit portion or the shield structure functions as one element for determining the resonant frequency. 
     The floating capacitance component of the coil, the capacitance of the capacitor element, or the like is used as the capacitance composing the resonance at this time. 
     Also, according to the embodiment of the present disclosure, the following effects can be obtained. 
     In the embodiment, the circuit portion is configured inside the coil shape, the circuit portion has the shield structure composed of the metallic box except for a part thereof composing the interface portion with the outside, and thus the circuit portion is configured as a part of the coil. As a result, when the circuit portion and the coil are disposed adjacent to each other (disposed close to each other), it is possible to prevent the characteristics deterioration due to the floating capacitance, the eddy-current loss and the like from being caused. 
     In addition, since the circuit portion and the coil can be integrated with each other, it is possible to reduce the entire size. 
     The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2010-192088 filed in the Japan Patent Office on Aug. 30, 2010, the entire content of which is hereby incorporated by reference. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.