JP2007317838A - Circuit apparatus, and surface mounting coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturized circuit apparatus where quality is stabilized, and to provide a surface mounting coil. <P>SOLUTION: The circuit apparatus 10A has a multilayered wiring layer. A coil wiring formed of the wiring layer patterned in a C shape forms winding of a coil. A coil 12 formed of a first wiring layer 13 and the like is formed in a part of the wiring board 11. An insulating layer whose thickness is several 50 μm to 200 μm is located between coil wiring parts. Relative positions in a thickness direction of the coil wiring parts are fixed by the insulating layer and they do not move. Thus, performance of the coil 12 formed of the coil wiring parts is stable as the coil since the coil wiring parts equivalent to winding of the coil do not move. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a circuit device in which a coil is incorporated in a substrate, and a thin surface-mounted coil.

  The configuration of the conventional circuit device 100 will be described with reference to FIG. 7A is a cross-sectional view of the circuit device 100, and FIG. 7B is a perspective view of the coil 105 mounted on the substrate.

  Referring to FIG. 7A, a conventional circuit device 100 includes a substrate 101, a conductive pattern 102 patterned on the surface of the substrate 101, and circuit elements such as a semiconductor element 103 connected to the conductive pattern 102. Consists of.

  The substrate 101 is made of a material that can mechanically support an electric circuit incorporated on the surface. For example, a resin material such as glass epoxy, a ceramic, a metal substrate, or the like is employed. As a circuit element electrically connected to the conductive pattern 102 on the upper surface of the substrate 101, a semiconductor element 103, a chip element 104, a coil 105, etc. are employed as shown in the figure. By incorporating an electric circuit composed of the conductive pattern 102 and circuit elements on the upper surface of the substrate 101 made of a material having excellent heat dissipation, heat generated by driving the electric circuit can be satisfactorily transmitted to the outside through the substrate 101. The heat can be dissipated (see, for example, Patent Document 1). One application field of the circuit device 100 having such a configuration is, for example, an audio amplifier module.

With reference to FIG. 7B, a structure of the coil 105 which is one of the circuit elements mounted on the upper surface of the substrate 101 will be described. The coil 105 has a conducting wire 106 housed inside a housing 107 made of an insulating material such as a plus chip. Here, the conductive 106 is formed by winding a copper thin wire having a linear shape of about 0.5 mm in a substantially circular shape in the vertical direction. Also, two electrodes are provided on the bottom surface of the coil 105, and the coil 105 can be surface-mounted through these electrodes. Further, a magnetic core made of ferrite or the like may be accommodated inside the conductive wire 106. Further, the housing 107 may be made of a magnetic material.
JP 2000-12987 (page 4, FIG. 1)

  However, in the coil 105 described above, the position of the conductive wire 106 wound in a spiral shape is not fixed. For this reason, when an impact is applied to the coil 105 under use conditions, there is a problem in that the conductive wire 106 is partially deformed, causing variations in the winding method, and the characteristics of the coil 105 are deteriorated.

  Furthermore, the size of the coil 105 is, for example, a cube whose length of one side is about 1 cm, and is larger than other circuit elements mounted on the upper surface of the substrate 101. Therefore, there is a problem that the circuit device 100 is increased in size by adopting the coil 105 as a circuit element mounted on the substrate 101.

  Furthermore, the circuit device 100 as described above has a problem that noise generated from the coil 105 mounted on the substrate 101 is large. Specifically, when the coil 105 was mounted directly on the surface of the substrate 101 made of resin or the like, electromagnetic waves (noise) generated from the coil 105 were leaked outside without being shielded. Therefore, this noise induces a deterioration in function and malfunction of other electronic devices mounted on the substrate 101. Furthermore, since the noise generated from the coil 105 is extremely large, this noise leaks to the outside from the set in which the coil 105 is built, and there is a risk of adversely affecting other sets.

  The present invention has been made in view of the above problems. Accordingly, a main object of the present invention is to provide a circuit device and a surface mount coil which are stabilized in quality and miniaturized.

  The circuit device according to the present invention is a circuit device including a wiring board in which a multilayer wiring layer laminated via an insulating layer is provided, and includes at least two coil wiring portions formed of a part of the wiring layer. A coil winding is formed by the coil wiring portion provided in the wiring layer and electrically connected through the insulating layer.

  Furthermore, in the circuit device of the present invention, a magnetic core is arranged on the wiring board inside the coil wiring portion.

  Furthermore, the circuit device of the present invention is characterized in that it includes a shield pattern that is formed of a part of the wiring layer and is provided so as to overlap the coil wiring portion.

  Furthermore, in the circuit device of the present invention, the shield pattern is connected to a fixed potential.

  Furthermore, the circuit device of the present invention is characterized in that the shield pattern is provided on the uppermost wiring layer and / or the lowermost wiring layer.

  Furthermore, in the circuit device of the present invention, the wiring layer is formed on a surface of a circuit board made of metal.

  The surface mount coil of the present invention includes a plurality of coil wiring portions that are stacked apart in the thickness direction, a connection portion that electrically connects the coil wiring portions to each other, and the coil wiring portion and the connection portion that are integrated with each other. The sealing body to coat | cover and the connection electrode connected with the said coil wiring part and provided in the main surface of the said sealing body are comprised, It is characterized by the above-mentioned.

  Furthermore, in the surface mount coil of the present invention, the sealing body inside the coil wiring part is partially removed in the thickness direction to provide a hole, and a magnetic core is disposed in the hole. To do.

  According to the circuit device of the present invention, a coil wiring portion serving as a coil winding is configured by using a part of a wiring layer formed in multiple layers on a wiring board. Therefore, the winding of the coil can be configured with the positional accuracy between the wiring layers configured on the wiring board, and the quality of the coil can be improved. Furthermore, since the position of the coil wiring portion is fixed inside the substrate, the characteristics of the coil do not change even when an impact or the like is applied from the outside.

  Furthermore, according to the circuit device of the present invention, the coil wiring portion, which is a coil winding, is housed in the wiring board, so that the above-described problem that the circuit device has become larger due to the mounting of the coil can be solved. .

  Further, according to the surface mount coil of the present invention, the multi-layered coil wiring portions constituting the coil winding are connected to each other by the connecting portion and are integrally sealed by the sealing body. Thereby, since the positions of the coil wiring portions are fixed by the sealing body, the relative positions of the coil wiring portions do not fluctuate even under use conditions. Accordingly, a coil with improved quality is provided.

  With reference to FIG. 1, the configuration of the circuit device 10A of the present embodiment will be described. 1A is a perspective view of the circuit device 10A, FIG. 1B is a cross-sectional view thereof, and FIG. 1C is a perspective view showing each wiring layer of the wiring board 11. FIG.

  Referring to FIGS. 1A and 1B, a circuit device 10A of the present invention has a multilayer wiring layer, and a coil wiring portion in which a part of the wiring layer is patterned in a C-shape, and It is made up. That is, the coil portion 12 including the first wiring layer 13 and the like is formed on a part of the wiring substrate 11.

  Referring to FIG. 1B, the wiring substrate 11 includes four wiring layers. From the upper layer, the first wiring layer 13, the second wiring layer 14, the third wiring layer 15, and the fourth wiring layer 16 are formed. Is formed. The width of these wiring layers can be finely formed, for example, about 20 μm to 100 μm, and the distance between patterns included in one layer can be shortened to about 50 μm to 100 μm. The thickness of each wiring layer is, for example, about 50 μm to 100 μm. Here, as a material of each wiring layer, copper, iron, aluminum, or an alloy containing these metals is employed. Each wiring layer is laminated via an insulating layer 37 made of a resin material such as glass epoxy resin or ceramic. Here, the thickness of the insulating layer 37 is, for example, about 50 μm to 200 μm.

  In this embodiment, each wiring layer is patterned in a C shape to form the coil wiring portion 17 and the like. The coil wiring portion is a wiring layer functioning as a part of the coil winding. Here, the coil wiring portion is a wiring that exhibits a shape of the alphabet “C” in a plan view, in other words, a shape obtained by partially cutting a circularly formed wiring. Further, the planar shape of the coil wiring portion may be a polygonal shape such as a substantially circular shape, an elliptical shape, or a quadrangle. The diameter of the coil wiring portion is in the range of about 1 mm to 5 cm and follows the required coil capacity. Moreover, the thickness of the wiring which comprises a coil wiring part is based on the magnitude | size of the electric current which passes in the range of tens of micrometers-several mm, for example.

  In this embodiment, a coil wiring portion is provided in each of the wiring layers formed in multiple layers. Specifically, coil wiring portions 17, 18, 19, and 20 are formed in each of the first wiring layer 13, the second wiring layer 14, the third wiring layer 15, and the fourth wiring layer 16 described above. Each coil wiring portion is connected by a connection portion made of a conductive material that penetrates the insulating layer 37.

  An insulating layer having a thickness of about several 50 μm to 200 μm is located between the coil wiring portions described above. Accordingly, the relative positions of the coil wiring portions in the thickness direction are fixed by the insulating layer and do not move. From this, the coil part 12 including the coil wiring part has a stable performance as a coil because the coil wiring part corresponding to the winding of the coil does not move.

  Furthermore, in this embodiment, the coil portion 12 is housed in the thickness portion of the wiring board 11 and does not protrude in the thickness direction of the wiring board 11. Therefore, the circuit device 10A including the coil can be thinned.

  Referring to FIG. 1C, the coil wiring portions of each layer are connected to each other through a connection portion that penetrates the insulating layer 37. In this figure, in order to explain the shape of the coil wiring portion, the first wiring layer 13, the second wiring layer 14, the third wiring layer 15 and the fourth wiring layer 16 are shown separated in the thickness direction. Specifically, the uppermost coil wiring part 17 and the coil wiring part 18 thereunder are connected by a connection part 21. The coil wiring portion 18 and the coil wiring portion 19 below the coil wiring portion 18 are connected via a connection portion 22. Furthermore, the coil wiring part 19 and the lowermost coil wiring part 20 are connected via a connection part 23. In the figure, the flow of current flowing through the coil portion 12 is indicated by arrows, and a magnetic field is generated by the current flowing in this way, and the coil portion 12 functions as a coil.

  In the above-described embodiment, the coil wiring part is formed in each of the four wiring layers and the coil part 12 wound four times is formed. However, the number of wiring layers is arbitrary and may be three or less. However, five or more layers may be used. Furthermore, it is not necessary to form the coil wiring part in all the wiring layers stacked in multiple layers, and it is sufficient that the coil wiring part constituting the coil is formed in at least two wiring layers.

  Although not shown here, a circuit element other than the coil portion 12 may be mounted on the upper surface of the wiring board 11. For example, active elements such as LSIs and transistors, and other passive elements such as capacitors and resistors may be mounted on the upper surface of the wiring board 11.

  Furthermore, you may arrange | position an annular | circular magnetic body so that the coil part 12 may be enclosed. This annular magnetic body is made of ferrite or the like, and may be housed in the thickness portion of the wiring board 11 or may be disposed on the upper surface of the wiring board 11. Thus, by arrange | positioning a cyclic | annular magnetic body, the inductance of the coil part 12 can further be enlarged.

  Next, a configuration of another form of circuit device 10B will be described with reference to FIG. 2A is a perspective view of the circuit device 10B, and FIG. 2B is a cross-sectional view thereof.

  2A and 2B, the basic configuration of the circuit device 10B is the same as that of the circuit device 10A described above, and the difference is that the magnetic core body 24 is employed. Here, a hole 26 is provided near the center of the coil portion 12, and the magnetic core body 24 is inserted into the hole 26. The magnetic core body 24 has an effect of increasing the inductance of the coil portion 12. Therefore, when the coil portion 12 having the same inductance is formed, the coil portion 12 can be reduced in size by adopting the magnetic core body 24. Moreover, if the size of the coil part 12 is the same, the inductance can be increased by adopting the magnetic core body 24.

  The hole portion 26 is a portion provided by partially removing the wiring board 11 inside the coil portion 12. Referring to FIG. 2B, the hole 26 is provided through the wiring substrate 11. Here, the hole 26 does not necessarily have to be provided through the wiring substrate 11, and may be a concave shape that can accommodate the magnetic core body 24.

  The magnetic core body 24 is made of a material having a high magnetic permeability such as ferrite and is accommodated in the hole 26. The shape of the hole 26 may be a cylindrical shape or a prismatic shape as illustrated. The vicinity of the upper end portion of the magnetic core body 24 is partially formed with a diameter larger than that of the hole portion 26. Thus, when the magnetic core body 24 is inserted into the hole 26 penetrating the wiring board 11, the upper end portion of the wide magnetic core body 24 comes into contact with the upper surface of the wiring board 11, thereby preventing the magnetic core body 24 from being detached. can do. Further, the magnetic core body 24 is bonded to the wiring board 11 using an insulating adhesive such as an epoxy resin.

  With reference to FIG. 3, the configuration of still another form of circuit device will be described. 3A and 3B are cross-sectional views of the circuit devices 10C and 10D, respectively.

  The basic configuration of the circuit device 10 </ b> C shown in FIG. 3A is the same as the circuit device 10 </ b> A described above, and the difference is that a shield pattern 25 is provided. Specifically, the wiring board 11 is provided with coil wiring portions 17 to 19 in each of the first wiring layer 13 to the third wiring layer 15. The lowermost fourth wiring layer 16 is not provided with a coil wiring portion, and a shield pattern 25 is formed on the fourth wiring layer 16 at a location corresponding to the coil portion 12. Here, the shield pattern 25 is an unpatterned solid wiring layer provided at a location where the coil portion 12 is formed, and has a function of reducing leakage of magnetism generated from the coil portion 12 to the outside. . Here, when the shield pattern 25 is connected to a fixed potential (for example, a ground potential or a power supply potential), the function of the shield pattern 25 can be improved.

  Here, the shield pattern 25 is not necessarily provided in the lowermost fourth wiring layer 16, and may be provided in the uppermost first wiring layer 13 of the coil portion 12, or the second wiring layer 14 or the like. It may be provided in the intermediate layer. Furthermore, a shield pattern 25 may be provided on both the first wiring layer 13 and the fourth wiring layer 16 corresponding to the coil portion 12.

  The basic configuration of the circuit device 10D shown in FIG. 3B is the same as that of the circuit device 10B described above, and the difference is that a shield pattern 25 is provided. Here, a hole 26 is formed halfway in the thickness direction of the wiring substrate 11, and the magnetic core body 24 is accommodated in the hole 26. Further, a shield pattern 25 made of the fourth wiring layer 16 is provided at a location where the coil portion 12 is provided.

  With reference to FIG. 4, the structure of the hybrid integrated circuit device 30 to which the structure of the coil section 12 described above is applied will be described. 4A is a perspective view showing the appearance of the hybrid integrated circuit device 30, and FIG. 4B is a cross-sectional view taken along line XX ′ in FIG. 4A. C) is an enlarged sectional view.

  Referring to FIGS. 4A and 4B, hybrid integrated circuit device 30 includes a circuit board 31 having an insulating layer 32 provided on the surface, and a wiring layer 33 patterned on the upper surface of insulating layer 32. A circuit element 35 electrically connected to the wiring layer 33, a lead 36 connected to a pad made of the wiring layer 33 and functioning as an input / output terminal to the outside, and an upper surface, a side surface and a lower surface of the circuit board 31 are covered. Sealing resin 34 to be provided. Further, a coil portion 12 composed of wiring layers 33 stacked in multiple layers is formed on the upper surface of the circuit board 31.

  As the material of the circuit board 31, aluminum, copper, alloy or the like is adopted. When a metal board made of aluminum is adopted, both surfaces thereof are alumite treated. The insulating layer 32 is formed over the entire upper surface of the circuit board 31 and has a function of insulating the wiring layer 33 and the circuit board 31. Further, in order to positively transmit the heat generated from the circuit element to the circuit board 31, the insulating layer 32 is made of a resin highly filled with an inorganic filler such as alumina.

  The wiring layer 33 is a multilayer wiring layer laminated via an insulating layer, and is composed of, for example, four wiring layers. Here, the wiring layer 33 connects the circuit elements 35 to form a predetermined electric circuit, and also functions as a coil in the coil portion 12.

  The circuit element 35 is mounted on a predetermined portion of the wiring layer 33 located on the uppermost layer via a bonding material such as solder or conductive paste. As the circuit element 35, a passive element, an active element, a circuit device, or the like can be generally employed. As the passive element, a resistor, a capacitor, a coil, or the like is adopted. As the active element, a transistor, a diode, an IC, an LSI, or the like is adopted. Also, a resin packaged IC may be fixed as a circuit element.

  The lead 36 is fixed to a pad made of the wiring layer 33 through a bonding material such as solder, and serves as a connection means for performing electrical input / output with the outside. The sealing resin 34 covers the wiring layer 33 and the circuit element 35 formed on the surface of the circuit board 31.

  With reference to FIG. 4C, the coil portion 12 is constituted by a part of the first wiring layer 13 to the fourth wiring layer 16 on the upper surface of the circuit board 31. Specifically, similarly to the circuit device 10A described above, a coil using the coil wiring portions 17, 18, 19, and 20 as windings is configured. By incorporating the coil unit 12 on the upper surface of the circuit board 31, it is not necessary to mount a coil as the circuit element 35, so that the number of parts can be reduced and the entire apparatus can be made thinner. Further, the first wiring layer 13 having a normal wiring shape may be formed on the coil portion 12 without providing the coil wiring portion on the first wiring layer 13 of the uppermost layer. Further, a pad made of the first wiring layer 13 may be provided in the area of the coil portion 12 and a circuit element may be mounted on this pad.

  Since the circuit board 31 is made of a metal material such as aluminum, the circuit board 31 blocks the spread of the magnetic field generated from the coil portion 12 to the outside. Further, when the circuit board 31 is electrically connected to the wiring layer through the insulating layer 32 and connected to a fixed potential (ground potential or power supply potential) or the like, the above-described blocking effect can be further increased. .

  Here, the configurations of all the coil units 12 shown in the circuit devices 10 </ b> A to 10 </ b> D can be applied to the hybrid integrated circuit device 30. That is, the magnetic core body 24 shown in FIG. 2 may be applied to the coil portion 12. Furthermore, as shown in FIG. 3, a part of the wiring layer located in the coil portion 12 may be a shield pattern.

  Next, the configuration of the surface mount coil 40 of this embodiment will be described with reference to FIG. FIG. 5A is a perspective view showing a state where the surface mount coil 40 is mounted, FIG. 5B is a cross-sectional view of the surface mount coil 40, and FIG. 5C shows the structure of the surface mount coil. It is a perspective view shown in more detail.

  Referring to FIG. 5A, the surface mount coil 40 has a configuration in which the wirings constituting the coil winding are integrally sealed by a sealing body 41. In addition, a hole 43 is formed near the center of the sealing body 41 by removing the sealing body in the thickness direction, and the magnetic core body 42 is accommodated in the hole 43. Here, the surface mount coil 40 may be configured by removing the magnetic core body 42.

  The planar shape of the sealing body 41 may be other than a circle, and may be a polygon such as a quadrangle. The diameter of the sealing body 41 is, for example, about 5 mm to 5 cm, and the thickness is about 1 mm to 5 mm. Further, the material of the sealing body 41 may be a material mainly made of a resin such as a glass epoxy resin, or may be ceramic.

  Referring to FIG. 5A, the surface mount coil 40 having the above configuration is surface mounted on the surface of the wiring substrate 60 via a conductive adhesive such as solder. Here, two pads 62 and 63 made of a wiring layer 61 are formed on the surface of the wiring board 60, and an electrode (not shown) located on the back surface of the surface mount coil 40 is connected to the pad.

  Referring to FIGS. 5B and 5C, three layers of coil wiring portions 44, 45, and 46 each including a wiring layer are formed inside sealing body 41. The size of the coil wiring portion 44 and the like may be the same as that described above with reference to FIG.

  Each coil wiring part is connected via the connection part which consists of electrically conductive materials. The uppermost coil wiring portion 44 is connected to the coil wiring portion 45 via the connection portion 47. The coil wiring part 45 is connected to the coil wiring part 46 via the connection part 48. Further, the coil wiring portion 46 is connected to the connection electrode 52 which is the lowermost wiring layer via the connection portion 49. Further, the uppermost coil wiring portion 44 and the lowermost connection electrode 51 are connected by a connection portion 50 that penetrates the sealing body 41 in the thickness direction. In FIG. 5C, the flow of current flowing from the connection electrode 51 is indicated by a thick arrow.

  In the surface mount coil 40 of this embodiment, each coil wiring portion is embedded in a sealing body 41 made of a resin material and the relative position is fixed. Therefore, the coil wiring portion is not deformed even under use conditions, and the deterioration of the coil characteristics is suppressed. Further, since the surface mount coil 40 is formed by integrally sealing a plurality of laminated coil wiring portions with resin or the like, the surface mount coil 40 is compared with the chip coil of the background art in which the winding is sealed with a case material. Then, miniaturization can be achieved.

  The surface mount coil having the above-described configuration may be mounted on a substrate made of a resin material or ceramic, or may be fixed to the upper surface of the circuit substrate 31 of the hybrid integrated circuit device 30 as shown in FIG. Furthermore, referring to FIG. 1, a surface mount coil 40 may be disposed on the upper portion of the coil portion 12 of the wiring board 11. In this case, a coil having a large inductance can be constituted by the coil wiring part built in the wiring board 11 and the coil wiring part built in the surface mount coil. Here, the magnetic core may be arranged so as to continuously penetrate the coil portion 12 provided on the substrate and the surface mount coil.

  Next, a method for manufacturing the circuit device 10A (wiring board 11) shown in FIG. 1 will be described with reference to FIG. Each drawing in FIG. 6 is a cross-sectional view showing a method for manufacturing the circuit device 10A.

  With reference to FIG. 6A, first, the upper surface and the lower surface of the first insulating layer 70 are covered with a first conductive film 71 and a second conductive film 72. The first insulating layer 70 is made of, for example, a glass epoxy substrate having a thickness of about 50 μm to several hundred μm. The first conductive film 71 and the second conductive film 72 are made of a metal material such as copper, and are formed so as to cover both main surfaces of the first insulating layer 70 by a rolling method or a plating method. In addition, the first conductive film 71 and the second conductive film 72 are connected via a connection portion 77 that penetrates the first insulating layer 70 at a predetermined location. Here, the connecting portion 77 uses a removing means such as a laser to provide a through hole in a predetermined portion of the first insulating layer 70, and then embeds a conductive material such as copper in the through hole by a plating method or the like. Formed with.

  Referring to FIG. 6B, next, first conductive film 71 and second conductive film 72 are selectively removed, and second wiring layer 14 and third wiring layer 15 are patterned into a predetermined shape. . When this step is performed by wet etching, the first conductive film 71 and the second conductive film 72 that are to remain are covered with an etching-resistant mask (not shown), and then the portion of the conductive film exposed from the mask is used with an etchant. Remove. By this step, the second wiring layer 14 and the third wiring layer 15 having a predetermined shape are formed. Here, the second wiring layer 14 includes a coil wiring portion 18, and the third wiring layer 15 includes a coil wiring portion 19.

  Next, referring to FIG. 6C, a conductive film is further stacked with an insulating layer interposed therebetween. Specifically, the third conductive film 75 is attached via the second insulating layer 73 that covers the second wiring layer 14. Further, a fourth conductive film 76 is attached via a third insulating layer 74 that covers the third wiring layer 15. Here, the details of each conductive film and insulating layer are the same as described above. Further, a connection portion 78 that connects the third conductive film 75 and the second wiring layer 14 through the second insulating layer 73 is formed. In addition, a connection portion 79 that penetrates the third insulating layer 74 and connects the fourth conductive film 76 and the third wiring layer 15 is also formed.

  Referring to FIG. 6D, next, the third conductive film 75 and the fourth conductive film 76 are selectively etched to form the first wiring layer 13 and the fourth wiring layer 16. The details of the etching may be the same as described above. Here, the first wiring layer 13 includes the coil wiring portion 17, and the fourth wiring layer 16 includes the coil wiring portion 20.

  The circuit device 10A shown in FIG. 1 is manufactured by the above-described steps. When the circuit device 10B as shown in FIG. 2 is configured, a step of manufacturing the hole 26 and a step of inserting the magnetic core body 24 into the hole 26 are added to the above-described steps. Further, when the surface mount coil 40 shown in FIG. 5 is manufactured, the sealing body 41 is manufactured by punching the wiring board according to a predetermined shape.

  An audio amplifier composed of a class D amplifier and a low-pass filter can be considered as an application field of the circuit device and the surface mount coil of the present embodiment. This type of audio amplifier includes a class D amplifier that amplifies an input digital signal and a low-pass filter that generates an analog signal from the amplified digital signal. By using the circuit device or surface mount coil of this embodiment, the coil is small even if the switching device that constitutes the class D amplifier and the coil that constitutes the low-pass filter are mounted on the same mounting board. Therefore, an increase in the size of the circuit element including the coil can be suppressed.

It is a figure which shows the circuit apparatus of this invention, (A) is a perspective view, (B) It is sectional drawing, (C) is a perspective view. It is a figure which shows the circuit apparatus of this invention, (A) is a perspective view, (B) is sectional drawing. It is a figure which shows the circuit apparatus of this invention, (A) is sectional drawing, (B) is sectional drawing. It is a figure which shows the circuit apparatus of this invention, (A) is a perspective view, (B) is sectional drawing, (C) is sectional drawing. It is a figure which shows the surface mount coil of this invention, (A) is a perspective view, (B) is sectional drawing, (C) is a perspective view. It is a figure which shows the manufacturing method of the circuit apparatus of this invention, (A) to (D) is sectional drawing. It is a figure which shows the conventional circuit device, (A) is sectional drawing, (B) is a perspective view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10A, 10B, 10C Circuit apparatus 11 Wiring board 12 Coil part 13 1st wiring layer 14 2nd wiring layer 15 3rd wiring layer 16 4th wiring layer 17, 18, 19, 20 Coil wiring part 21, 22, 23 Connection part 24 Magnetic Core 25 Shield Pattern 26 Hole 30 Hybrid Integrated Circuit Device 31 Circuit Board 32 Insulating Layer 33 Wiring Layer 34 Sealing Resin 35 Circuit Element 36 Lead 37 Insulating Layer 40 Surface Mount Coil 41 Sealing Body 42 Magnetic Core 43 Hole Part 44, 45, 46 coil wiring part 47, 48, 49, 50 connection part 51, 52 connection electrode 60 wiring board 61 wiring layer 62, 63 pad 70 first insulating layer 71 first conductive film 72 second conductive film 73 second 2 insulating layer 74 3rd insulating layer 75 3rd conductive film 76 4th conductive film 77, 78, 79 Connection part

Claims (8)

In a circuit device comprising a wiring board in which a multilayer wiring layer laminated via an insulating layer is incorporated,
A coil wiring portion comprising a part of the wiring layer is provided in at least two or more of the wiring layers, and a coil winding is constituted by the coil wiring portion that is electrically connected through the insulating layer. A circuit device characterized.   The circuit device according to claim 1, wherein a magnetic core is arranged on the wiring board inside the coil wiring portion.   The circuit device according to claim 1, further comprising a shield pattern that is formed of a part of the wiring layer and is provided so as to overlap the coil wiring portion.   4. The circuit device according to claim 3, wherein the shield pattern is connected to a fixed potential.   4. The circuit device according to claim 3, wherein the shield pattern is provided on the uppermost wiring layer and / or the lowermost wiring layer.   The circuit device according to claim 1, wherein the wiring layer is formed on a surface of a circuit board made of metal. A plurality of coil wiring portions stacked apart in the thickness direction;
A connecting portion for electrically connecting the coil wiring portions to each other;
A sealing body that integrally covers the coil wiring portion and the connection portion;
A surface mount coil comprising a connection electrode connected to the coil wiring portion and provided on a main surface of the sealing body. The sealing body inside the coil wiring part is partially removed in the thickness direction to provide a hole,
The surface mount coil according to claim 7, wherein a magnetic core is disposed in the hole.

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