JP2015079778A - Coil-integrated printed circuit board and magnetic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil-integrated printed circuit board that can be easily manufactured even though the winding number of the coil is increased and can suppress temperature from rising even though heat is generated from the coil, and a magnetic device comprising the same.SOLUTION: A coil-integrated printed circuit board 3 comprises coil patterns 4a and 4b in inner layers L2 and L3 and comprises an outer coil 11 in a surface layer L1, thereof. A magnetic device 1 comprises the coil-integrated printed circuit board 3 and a core 2a penetrating through the board 3. The core 2a is a common core for the coil patterns 4a and 4b and the outer coil 11. The coil patterns 4a and 4b are formed in the coil-integrated printed circuit board 3 by printing to be wound around a protruding part 2m of the core 2a. The outer coil 11 is surface-mounted on the coil-integrated printed circuit board 3 to be wound around the protruding part 2m of the core 2a. One ends pf the coil patterns 4a and 4b are electrically connected to one end of the outer coil 11.

Description

  The present invention relates to a coil-integrated printed board on which a coil pattern is formed, and a magnetic device including the board.

  For example, there is a switching power supply device such as a DC-DC converter (DC-DC converter) that converts a high-voltage direct current into a alternating current after switching to a low-voltage direct current. The switching power supply device uses a magnetic device such as a choke coil or a transformer.

  For example, Patent Literature 1 and Patent Literature 2 disclose a coil-integrated printed board on which a coil pattern is formed by printing as a coil winding, and a magnetic device including the board. Specifically, a core made of a magnetic material passes through the substrate. A coil pattern is formed on the surface layer of the substrate and the inner layer that is not exposed to the outside so as to be wound around the core. In each layer, the coil pattern is wound a plurality of times. Coil patterns of different layers are connected by through holes that penetrate the substrate. A surface electrode for inputting / outputting electric power to / from the coil pattern is provided on the surface layer of the substrate. The end portion of the coil pattern in a different layer from the surface electrode is connected by a through hole.

Further, for example, Patent Document 3 discloses a surface mount type coil component in which a winding coil is incorporated, and a substrate on which the coil component is surface mounted. Specifically, external electrodes formed on both ends of the coil protrude from the side surface of the coil component, bend to the bottom of the bottom surface, and are soldered to the surface of the substrate.

Japanese Unexamined Patent Publication No. 7-38262 Japanese Patent Laid-Open No. 7-86755 JP 2004-207355 A

  In a magnetic device used in a DC-DC converter, a large current flows through a coil. When the coil winding is configured with a coil pattern formed on the surface layer or inner layer of the substrate, in order to allow a large current to flow normally, the width and thickness of the coil pattern must be increased and the cross-sectional area of the coil pattern should be increased to some extent. It needs to be large. However, if the width of the coil pattern is widened, it becomes difficult to increase the number of turns of the coil pattern in a limited area of the substrate, and it becomes difficult to increase the number of turns of the coil.

  In addition, in the DC-DC converter, there is a demand for providing a magnetic device and other electronic components and electric circuits on the same substrate in order to reduce the size, and increasing the mounting density of the substrate. However, for example, as shown in FIG. 12, in the printed circuit board B, the bases of the conductors Da and Db increase as the thicknesses ta and tb of the conductors (metal foils such as copper) Da and Db such as patterns increase (ta> tb). Since the widths Wa and Wb of the portion Ds are increased (Wa> Wb), the mounting density is decreased. Therefore, in the substrate of the DC-DC converter, it is conceivable to increase the thickness of the conductor where the coil pattern is to be disposed and to decrease the thickness of the conductor where the other electronic components are disposed. However, if the thickness of the conductor is different in the same layer, the manufacturing process of the layer increases, and the manufacture of the substrate becomes difficult.

  Further, when a large current is passed through the coil pattern, heat is generated from the coil pattern and the temperature of the substrate rises. When the temperature of the substrate becomes high, there is a risk that the characteristics of the magnetic device will vary and the performance will deteriorate. There is also a risk of malfunction or destruction of electronic components such as IC chips mounted on the same substrate.

  An object of the present invention is to provide a coil-integrated printed circuit board that can be easily manufactured even if the number of turns of the coil is increased, and that can suppress a temperature rise even if heat is generated from the coil, and a magnetic circuit including the circuit board. Is to provide a device.

  The coil-integrated printed board of the present invention is a printed board in which a coil pattern is formed on one or more layers by printing, and includes an external coil that is surface-mounted on the coil-integrated printed board. The coil pattern and the external coil are wound around a common core that penetrates the coil-integrated printed board, and one end of the coil pattern and one end of the external coil are electrically connected.

  The magnetic device of the present invention includes the coil-integrated printed board and a core made of a magnetic material and penetrating the coil-integrated printed board. A coil pattern is formed on the coil-integrated printed board so as to be wound around the core, and the external coil is surface-mounted.

  According to the above, a series of coils is constituted by the coil pattern formed on the coil-integrated printed board and the external coil surface-mounted on the coil-integrated printed board. For this reason, even if it is difficult to secure a large number of turns of the coil pattern in a limited area of the coil-integrated printed board, the number of turns of the coil can be increased by connecting the external coil to the coil pattern. . Further, the external coil can be easily attached to the coil-integrated printed board by surface mounting. Therefore, even if the number of turns of the coil is increased, the coil-integrated printed board can be easily manufactured.

  In addition, since the external coil is surface-mounted on the coil-integrated printed board, the surface layer of the coil-integrated printed board can increase the cross-sectional area of the external coil 11 without increasing the thickness of the conductor. Current can flow normally. Further, by reducing the thickness of the conductor of the surface layer, other electronic components and electric circuits can be mounted with high density. Therefore, it is possible to easily manufacture a coil integrated type printed circuit board by making the thickness of the conductor the same in each part of the surface layer, reducing the manufacturing process of the surface layer. Furthermore, when the current flows through the coil, the heat generated from the external coil is dissipated to the surroundings, so that the temperature increase of the coil-integrated printed board due to the heat generated from the coil can be suppressed.

  In the present invention, the coil-integrated printed circuit board further includes a pair of surface electrodes for inputting and outputting power, and one of the pair of surface electrodes is electrically connected to the other end of the external coil. The other surface electrode may be electrically connected to the other end of the coil pattern.

  In the present invention, the following configuration may be adopted in the coil-integrated printed board. The coil pattern is formed on an inner layer that is not exposed to the outside, and the outer coil and the pair of surface electrodes are provided on the same surface layer. Also, the first connection means for electrically connecting one surface electrode and the other end of the external coil, and the coil integrated printed circuit board are penetrated, and one end of the external coil and one end of the coil pattern are electrically connected. Second connection means that connects to the coil-integrated printed circuit board, and electrically connects the other surface electrode and the other end of the coil pattern. And each connection means is arrange | positioned so that it may not each overlap in the board surface of the said coil integrated type printed circuit board.

  In the present invention, in the coil-integrated printed board, the external coil may be surface-mounted so as not to overlap the other surface electrode and the third connecting means on the plate surface of the coil-integrated printed board. Good.

  In the present invention, in the coil integrated printed circuit board, the coil patterns are formed in a plurality of layers, and the coil patterns in different layers are electrically connected to each other through the coil integrated printed circuit board. You may further provide the 4th connection means. In this case, the fourth connecting means may be arranged so as not to overlap the first connecting means, the second connecting means, and the third connecting means on the plate surface of the coil-integrated printed board.

  In the present invention, in the coil-integrated printed board, the external coil may be formed in a cylindrical shape by bending a metal plate.

  Furthermore, in this invention, you may provide an unevenness | corrugation on the periphery of an external coil in the said coil integrated type printed circuit board.

  According to the present invention, a coil-integrated printed circuit board that can be easily manufactured even when the number of turns of the coil is increased and that can suppress a temperature rise even when heat is generated from the coil, and a magnetic circuit including the substrate A device can be provided.

It is a block diagram of a switching power supply device. It is a disassembled perspective view of the magnetic device by embodiment of this invention. It is the perspective view which showed the state which assembled | attached the external coil and the core to the coil integrated type printed circuit board of FIGS. It is a top view of the surface layer and inner layer of the A section of the coil integrated type printed circuit board of FIG. 2-1. It is a top view of the back surface layer of the A section of the coil integrated type printed circuit board of FIGS. It is XX sectional drawing of FIGS. 3-1 and FIGS. 3-2. It is YY sectional drawing of FIGS. 3-1 and FIGS. 3-2. It is ZZ sectional drawing of FIGS. 3-1 and FIGS. 3-2. It is VV sectional drawing of FIGS. 3-1 and FIGS. 3-2. It is the figure which showed the detail of the external coil of FIGS. It is the figure which showed a part of manufacturing process of the external coil of FIGS. It is a perspective view of the external coil by other embodiment. It is the figure which showed a part of manufacturing process of the external coil by a comparative example. It is the figure which showed an example of the conductor on a printed circuit board.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a configuration diagram of the switching power supply apparatus 100. The switching power supply device 100 is a DC-DC converter for an electric vehicle (or a hybrid car), which switches a high-voltage direct current to an alternating current and then converts it to a low-voltage direct current. This will be described in detail below.

  A high voltage battery 50 is connected to the input terminals T <b> 1 and T <b> 2 of the switching power supply device 100. The voltage of the high voltage battery 50 is, for example, DC 220V to DC 400V. The DC voltage Vi of the high-voltage battery 50 input to the input terminals T1 and T2 is applied to the switching circuit 52 after noise is removed by the filter circuit 51.

  The switching circuit 52 is formed of a known circuit having, for example, an FET (Field Effect Transistor). In the switching circuit 52, the FET is turned on / off based on a PWM (Pulse Width Modulation) signal from the PWM drive unit 58, and a switching operation is performed on the DC voltage. As a result, the DC voltage is converted into a high-frequency pulse voltage.

  The pulse voltage is given to the rectifier circuit 54 via the transformer 53. The rectifier circuit 54 rectifies the pulse voltage by a pair of diodes D1 and D2. The voltage rectified by the rectifier circuit 54 is input to the smoothing circuit 55. The smoothing circuit 55 smoothes the rectified voltage by the filtering action of the choke coil L and the capacitor C, and outputs the smoothed voltage to the output terminals T3 and T4 as a low DC voltage. With this DC voltage, the low voltage battery 60 connected to the output terminals T3 and T4 is charged to, for example, DC12V. The DC voltage of the low-voltage battery 60 is supplied to various on-vehicle electrical components (not shown).

  The output voltage Vo of the smoothing circuit 55 is detected by the output voltage detection circuit 59 and then output to the PWM drive unit 58. The PWM drive unit 58 calculates the duty ratio of the PWM signal based on the output voltage Vo, generates a PWM signal corresponding to the duty ratio, and outputs the PWM signal to the gate of the FET of the switching circuit 52. As a result, feedback control is performed to keep the output voltage constant.

  The control unit 57 controls the operation of the PWM drive unit 58. A power source 56 is connected to the output side of the filter circuit 51. The power supply 56 steps down the voltage of the high voltage battery 50 and supplies a power supply voltage (for example, DC 12 V) to the control unit 57.

  Each part of the switching power supply device 100 is mounted on a substrate 3 to be described later. A magnetic device 1 described later is used as the choke coil L of the smoothing circuit 55. A large current of, for example, DC 150A flows through the choke coil L. At both ends of the choke coil L, a pair of electrodes 8i and 8o for inputting and outputting electric power are provided as will be described later.

  Next, the structure of the magnetic device 1 will be described with reference to FIGS.

  FIG. 2A is an exploded perspective view of the magnetic device 1. FIG. 2-2 is a perspective view showing a state in which the external coil 11 and the core 2a are assembled to the coil-integrated printed board 3 (hereinafter simply referred to as “substrate 3”) of FIG. FIG. 3A is a plan view of the surface layer L1 and the inner layers L2 and L3 of part A of the substrate 3 in FIG. 3-2 is a plan view of the back layer L4 of the A part of the substrate 3 of FIG. 2-1. 4 to 7 are cross-sectional views of the magnetic device 1. Specifically, in FIGS. 3A and 3B, the XX cross section is shown in FIG. 4, the YY cross section is shown in FIG. 5, the ZZ cross section is shown in FIG. 6, and the VV cross section is shown. 7 shows.

  As shown in FIGS. 2A and 2B, the cores 2a and 2b are configured by a pair of an upper core 2a having an E-shaped cross section and a lower core 2b having an I-shaped cross section. The cores 2a and 2b are made of a magnetic material such as ferrite or amorphous metal.

  The upper core 2a has three convex portions 2m, 2L, and 2r so as to protrude downward. The convex portions 2m, 2L, and 2r are arranged in a line as shown in FIGS. 3-1, 3-2, and FIG. As shown in FIG. 5, the left and right convex portions 2L and 2r have a larger amount of protrusion than the central convex portion 2m.

  The lower ends of the left and right projections 2L, 2r of the upper core 2a are brought into close contact with the upper surface of the lower core 2b, and the cores 2a, 2b are combined. In this state, a gap of a predetermined size is provided on the upper surface of the convex portion 2m of the upper core 2a and the upper surface of the lower core 2b in order to improve the DC superimposition characteristics. Thereby, even when a large current is passed through the magnetic device 1 (choke coil L), a predetermined inductance can be realized. The cores 2a and 2b are fixed by fixing means such as screws and metal fittings (not shown). The lower core 2b is fitted into a recess 10k (FIG. 2-1) provided on the upper side of the heat sink 10. A fin 10 f is provided on the lower side of the heat sink 10. The heat sink 10 is made of metal such as aluminum.

  The substrate 3 is composed of a printed circuit board in which conductors such as patterns, pads, and lands are formed by printing a conductive metal foil such as copper on each layer of a thin base material made of an insulator. ing. In the present embodiment, on the substrate 3, illustration of electronic components and electric circuits other than the magnetic device 1 of the switching power supply apparatus 100 of FIG. 1 is omitted.

  A surface layer L1 as shown in FIG. 3-1 (a) is provided on the surface of the substrate 3 (upper surface in FIGS. 2-1, 2-2, and FIGS. 4 to 7). A back surface layer L4 as shown in FIG. 3-2 is provided on the back surface of the substrate 3 (the bottom surface in FIGS. 2-1, 2-2, and 4 to 7). As shown in FIGS. 4 to 7, inner layers L2 and L3 as shown in FIGS. 3B and 3C are provided between the surface layer L1 and the back surface layer L4. That is, the substrate 3 is a multilayer substrate having a total of four layers L1 to L4, two outer surface layers L1 and L4 exposed to the outside and two inner layers L2 and L3 not exposed to the outside. Note that a multi-layer substrate is a substrate having two or more layers. Further, the layer L4 on the back surface of the substrate 3 is also a surface layer in a broad sense, but in the present embodiment, it is referred to as a back surface layer L4 in order to distinguish it from the surface layer L1.

  The substrate 3 is provided with a plurality of openings 3m, 3L, and 3r. The opening 3m is a large-diameter circular through hole, and the openings 3L and 3r are substantially concave through-holes. As shown in FIG. 2-1, FIG. 3-1, FIG. 3-2, FIG. 5 and FIG. 7, the center convex portion 2m of the core 2a is inserted into one opening 3m at the center, The left and right projections 2L and 2r of the core 2a are inserted into the openings 3L and 3r, respectively. As shown in FIGS. 4 to 7, the heat sink 10 is fixed to the back surface layer L4 side of the substrate 3 by fixing means such as screws (not shown). An insulating sheet 12 having heat conductivity is sandwiched between the substrate 3 and the heat sink 10. Since the insulating sheet 12 has flexibility, it is in close contact with the substrate 3 and the heat sink 10 without a gap.

As shown in FIGS. 3A and 3B, the substrate 3 includes through holes 8a, 8b, and 8d, through hole groups 9a and 9b, surface electrodes 8i and 8o, lands 8c, patterns 4a to 4h, and 4t _1. ~4t _{4, 5t} 1 ~5t _8, pad 8e, 8f, 8g, and pin 6i, 6o, conductors are provided such 7a to 7d. The through holes 8a, 8b, 8d, the through hole groups 9a, 9b, and the pins 6i, 6o, 7a-7d are provided so as to penetrate the substrate 3 (see FIGS. 4, 6, and 7).

As shown in FIGS. 4 to 7, the conductor (surface electrode 8i on the surface layer L1 and the back layer L4 of the substrate 3, 8o, land 8c, pattern _4c~4e, 5t 1 ~5t _4, and the pad 8e, 8f, 8g etc.) consists of a thin copper foil. In contrast, the inner layer L2, L3 to a conductor (pattern _{4a, 4b, 4f, 4t 1} ~4t 4, 5t 5 ~5t 8 , etc.) is composed of thick copper foil.

  As shown in FIGS. 3A and 3B, conductive pins 6i and 6o made of a metal having conductivity such as copper are embedded in the pair of through holes 8a and 8b, respectively, in order to increase conductivity. Has been. A pair of front surface electrodes 8i and 8o are provided around the through holes 8a and 8b of the front surface layer L1 and the back surface layer L4. The surface electrodes 8i and 8o are also lands of the through holes 8a and 8b. Copper plating is applied to the surfaces of the conductive pins 6i, 6o and the surface electrodes 8i, 8o. The lower ends of the conductive pins 6i and 6o are in contact with the insulating sheet 12, as shown in FIG.

  Further, as shown in FIGS. 3A and 3B, the four through holes 8d are respectively provided with heat radiation pins 7a to 7d formed of a conductive metal such as copper in order to increase thermal conductivity. Buried. Lands 8c are provided around the through holes 8d in the front surface layer L1 and the back surface layer L4. Copper plating is applied to the surfaces of the heat radiation pins 7a to 7d and the land 8c. As shown in FIG. 6, the lower ends of the heat radiation pins 7a to 7d are in contact with the insulating sheet 12 (the cross sections of the heat radiation pins 7a and 7b are not shown).

As shown in FIG. 3A, a wiring pattern 4c, a relay pattern 4d, a rectangular pattern 4e, heat radiation patterns 5t _{1 to} 5t ₄ , and pads 8e to 8g are formed on the surface layer L1 of the substrate 3. Yes. Pattern _4c~4e, 5t 1 ~5t ₄ is separately respectively, are insulated. The surfaces of the patterns 4c to 4e and 5t _{1 to} 5t ₄ are subjected to insulation processing.

  One end of the wiring pattern 4c is connected to the surface electrode 8i, the through hole 8a, and the conductive pin 6i. The other end of the wiring pattern 4c is connected to the pad 8f. A through hole group 9a is provided at one end of the relay pattern 4d. The other end of the relay pattern 4d is connected to the pad 8e. A through hole group 9b is provided in the rectangular pattern 4e.

Radiating pattern 5t ₁ is connected to the through-holes 8d and lands 8c surrounding and this heat-radiating fin 7a, are insulated surface electrode 8o in the vicinity of the through holes 8b, and conductive pins 6o and. Radiating pattern 5t ₂ is connected to the through hole 8d and lands 8c surrounding and this heat-radiating fin 7c. Radiating pattern 5t ₃ is connected to the through hole 8d and lands 8c surrounding and this heat-radiating fin 7d. Radiating pattern 5t ₄ is connected to the through-holes 8d and lands 8c surrounding and this heat-radiating fin 7b, are insulated surface electrode 8i in the vicinity of the through holes 8a, and the conductive pin 6i.

The pads 8 e to 8 g are separate from each other and are arranged around the central through hole 3 m of the substrate 3. Copper plating is applied to the surfaces of the pads 8e to 8g. Pad 8e is insulated pattern 4c except relay pattern 4d, _4e, with respect to 5t 1 ~5t _4. Pad 8f, the pattern 4d other than the wiring pattern 4c, _4e, are insulated against 5t 1 ~5t _4. Pad 8g is insulated pattern _4c~4e, 5t 1 ~5t _4.

  The external coil 11 is surface-mounted on the surface layer L1. 8A and 8B are diagrams showing details of the external coil 11, wherein FIG. 8A is a plan view of the external coil 11, and FIG. 8B is a side view of the external coil 11 of FIG. (C) has shown the side view which looked at the external coil 11 of (a) from the lower side. FIG. 9 is a diagram showing a part of the manufacturing process of the external coil 11.

  The external coil 11 is formed by punching a coil metal plate 11 ′ from a metal strip 13 made of copper or the like and bending the coil metal plate 11 ′ with a press machine or the like (not shown). As shown in FIG. 8, it is formed in a cylindrical shape (see also FIG. 2-1). That is, the radial direction and the plate thickness direction of the circumferential portion 11a (FIG. 8) of the external coil 11 are parallel to each other. The plate thickness t, plate width W, and cross-sectional area of the external coil 11 achieve a predetermined performance of the coil and suppress the amount of heat generated from the external coil 11 to some extent even when a predetermined large current (for example, DC 150A) is passed. And it is set so that heat can be radiated from the surface of the external coil 11.

  Input / output legs 11 e and 11 f for inputting and outputting electric power are formed at both ends of the external coil 11. A plurality of reinforcing legs 11 g for reinforcing attachment to the substrate 3 are formed on the circumferential portion 11 a of the external coil 11. Each leg part 11e-11g is formed in the L-shape so that it may extend once from the lower surface of the external coil 11, and may extend outside.

  As shown in FIG. 3A, the leg portions 11e to 11g of the external coil 11 are respectively disposed on the pads 8e to 8g of the surface layer L1 of the substrate 3, and the leg portions 11e to 11g and the pads 8e to 8g. Is externally mounted on the substrate 3 (see also FIG. 2-2 (a)). Since the central convex portion 2m of the core 2a is inserted into the through hole 3m from the surface side of the substrate 3 through the inside of the circumferential portion 11a of the external coil 11 (see also FIG. 2-2 (b)), the external The coil 11 is wound around the convex portion 2m of the core 2a. Each leg portion 11e to 11g is formed with a notch 11k (FIG. 8) in order to increase the bonding area by solder.

  In order to form the plurality of leg portions 11e to 11f, the coil metal plate 11 'before bending is formed in a comb shape as shown in FIG. Then, two pairs of coil metal plates 11 ′ are punched from the same region in the length direction of the metal strip 13 so that the comb-shaped portions intersect each other. Thereby, the waste of the metal strip 13 can be reduced.

In Figures 4-7, the inner layer L2 that is closer to the surface layer L1 of the substrate 3, as shown in FIG. 3-1 (b), heat radiating coil pattern 4a pattern _5t 5, 5t ₆ is formed Yes. The coil pattern 4a has extended regions 4t ₁ and 4t ₂ formed by extending a part of the pattern 4a in the width direction. Extended coil pattern 4a region _4t 1, 4t ₂ is are integrated, the coil pattern 4a and the extended area _4t 1, 4t _2, the heat radiation pattern _5t 5, 5t ₆ are each have been separately Insulated.

  The coil pattern 4a is formed in a strip shape parallel to the plate surface direction of the substrate 3, and is wound around the convex portion 2m of the core 2a. Therefore, the coil pattern 4a and the external coil 11 are wound around the common core 2a. A through hole group 9a is provided at one end of the coil pattern 4a, and a through hole group 9b is provided at the other end.

Extended area 4t ₁ coil pattern 4a is connected to the heat dissipation pins 7b and which around the through hole 8d, is insulated from the through hole 8a and the conductive pin 6i. Extension region 4t ₂ is connected to the heat dissipation pins 7d therewith around the through hole 8d. Radiating pattern 5t ₅ is connected to the heat dissipation pins 7a and which around the through hole 8d, is insulated from the through hole 8b and the conductive pin 6o. Radiating pattern 5t ₆ is connected to the heat radiating fin 7c and which the surrounding of the through hole 8d.

In Figures 4-7, the inner layer L3 closer to the back surface layer L4 of the substrate 3, as shown in FIG. 3-1 (c), the coil pattern 4b, rectangular patterns 4f, and the heat radiation pattern _5t 7, 5t ₈ is formed. The coil pattern 4b is formed with expanded regions 4t ₃ and 4t ₄ by extending a part of the pattern 4b in the width direction. The coil pattern 4b and the extended regions 4t ₃ and 4t ₄ are integrated. For extended area _4t 3, 4t ₄ and the coil pattern 4b, rectangular patterns 4f and the heat dissipation patterns _5t 7, 5t ₈ They become separately respectively, are insulated.

  The coil pattern 4b is formed in a strip shape parallel to the plate surface direction of the substrate 3, and is wound around the convex portion 2m of the core 2a. Therefore, the coil pattern 4b and the external coil 11 are wound around the common core 2a. A through hole group 9b is provided at one end of the coil pattern 4b, and the other end is connected to the through hole 8b and the conductive pin 6o. A through hole group 9a is provided in the rectangular pattern 4f.

Extended area 4t of the coil pattern 4b ₃ is connected to the heat dissipation pins 7a and which around the through hole 8d and the conductive pin 6o therewith around the through-hole 8b,. Extension area 4t ₄ is connected to the heat radiating fin 7c and which the surrounding of the through hole 8d. Radiating pattern 5t ₇ is connected to the heat dissipation pins 7b and which around the through hole 8d, is insulated from the through hole 8a and the conductive pin 6i. Radiating pattern 5t ₈ is connected to the heat dissipation pins 7d therewith around the through hole 8d.

  The width, thickness, and cross-sectional area of the coil patterns 4a and 4b suppress the amount of heat generated in the coil patterns 4a and 4b to some extent even when a predetermined large current (for example, DC150A) is passed while achieving the predetermined performance of the coil. And it is set so that heat can be radiated from the surfaces of the coil patterns 4a and 4b.

  As shown in FIG. 3B, two rectangular patterns 4g and 4h are formed on the back surface layer L4 of the substrate 3. The rectangular patterns 4g and 4h are separated and insulated. The rectangular patterns 4g and 4h are electrically insulated from the conductive pins 6i and 6o and their surrounding through holes 8a and 8b and the surface electrodes 8i and 8o, and the radiating pins 7a to 7d and their surrounding through holes 8d and lands 8c. Has been. One rectangular pattern 4g is provided with a through hole group 9a, and the other rectangular pattern 4h is provided with a through hole group 9b.

  The through-hole groups 9a and 9b are smaller in diameter than the through-holes 8a, 8b, and 8d, and as shown in FIG. 7, a plurality of through-holes that penetrate the substrate 3 are gathered at a predetermined interval. Copper plating is applied to the surface of each small-diameter through-hole constituting the through-hole groups 9a and 9b, and the inside of the through-hole is filled with copper or the like. The through-hole group 9a electrically connects the patterns 4d, 4a, 4f, and 4g of the different layers L1 to L4 that penetrate therethrough. The through-hole group 9b also electrically connects the patterns 4e, 4a, 4b, and 4h of the different layers L1 to L4 that penetrate therethrough.

  The through hole 8b and the conductive pin 6o electrically connect the surface electrode 8o of the different layers L1, L3, and L4 penetrating with the coil pattern 4b. The through hole 8a and the conductive pin 6i electrically connect the surface electrodes 8i of the different layers L1 and L4 that pass therethrough.

  As described above, the surface electrode 8i on the surface layer L1 and the input / output leg 11f of the external coil 11 are electrically connected to the wiring pattern 4c, the pad 8f, and the solder. The input / output leg 11e of the external coil 11 on the surface layer L1 and one end of the coil pattern 4a on the inner layer L2 are electrically connected by solder, the relay pattern 4d, and the through hole group 9a. The other end of the coil pattern 4a and one end of the coil pattern 4b in the inner layer L3 are electrically connected by a through hole group 9b. Furthermore, the other end of the coil pattern 4b and the surface electrode 8o in the surface layer L1 are electrically connected by a through hole 8b and a conductive pin 6o.

  In other words, the coil integrated with the substrate 3 is the surface layer L1, and the first time around the convex portion 2m of the core 2a by the external coil 11 via the wiring pattern 4c and the pad 8f from the starting surface electrode 8i. After being wound, it is connected to the inner layer L2 via the pad 8e, the relay pattern 4d, and the through hole group 9a. Next, the coil is connected to the inner layer L3 via the through-hole group 9b after the coil layer 4 is wound a second time around the convex portion 2m by the coil pattern 4a. The coil is the inner layer L3, and the coil pattern 4b is wound around the convex portion 2m for the third time, and then passes through the through hole 8b and the conductive pin 6o to the surface electrode 8o of the surface layer L1 that is the end point. Connected.

  Thus, surface electrode 8i, wiring pattern 4c, pad 8f, external coil 11, pad 8e, relay pattern 4d, through hole group 9a, coil pattern 4a, through hole group 9b, coil pattern 4b, and through hole with conductive pin 6o. A series of coil current paths connected in series in the order of 8b and the surface electrode 8o are formed. In addition, the wiring pattern 4c, the pads 8f and 8e, the relay pattern 4d, the through hole groups 9a and 9b, and the through hole 8b are arranged so as not to overlap each other on the plate surface of the substrate 3. The external coil 11 is surface-mounted so as not to overlap the surface electrode 8o, the conductive pin 6o, and the through hole 8b on the plate surface of the substrate 3.

  The wiring pattern 4c, the pad 8f, and the solder are examples of the “first connecting means” in the present invention. The pad 8e, the relay pattern 4d, the solder, and the through hole group 9a are an example of the “second connecting means” in the present invention. The conductive pin 6o and the through hole 8b are an example of the “third connection means” in the present invention. The through-hole group 9b is an example of the “fourth connection means” in the present invention.

Cooling fins 7b, 7d and the through-hole 8d and the land 8c of the surrounding, and the extended area _4t 1, 4t ₂ coil patterns 4a of the inner layer L2, the heat radiation pattern _5t 4 of the surface layer L1 and the inner layer _L3, 5t 3, 5t ₇ , 5t ₈ and the back surface layer L4 are thermally connected. Radiation fins 7a, 7c and a through hole 8d and the land 8c of the surrounding, and the extended area _4t 3, 4t ₄ of the coil pattern 4b of the inner layer L3, the heat radiation pattern _5t 1 of the surface layer L1 and the inner layer _L2, 5t 2, 5t ₅ , 5t ₆ and the back surface layer L4 are thermally connected. The conductive pin 6i, the surrounding through hole 8a, and the surface electrode 8i thermally connect the wiring pattern 4c of the surface layer L1 and the back surface layer L4.

  For this reason, when a large current flows through the coil through the above-described current path, heat from the wiring pattern 4c and the like in the surface layer L1 is dissipated around the surface layer L1, and the surface electrode 8i and the through hole 8a. , And through the conductive pin 6i, the heat sink 10 dissipates heat through the insulating sheet 12 on the back layer L4 side. Further, the heat generated from the external coil 11 is radiated from the surface of the external coil 11 itself.

Heat generated from the coil patterns 4a and 4b in the inner layers L2 and L3 is transmitted through the heat radiation pins 7a to 7d, the through holes 8d, the lands 8c, the through hole groups 9a and 9b, and the rectangular patterns 4e, 4g, and 4h, and the surface layer. Guided to L1 and back layer L4. The heat is radiated from the surfaces of the heat radiation patterns 5t _{1 to} 5t _{4 in} the surface layer L1, and is radiated by the heat sink 10 via the insulating sheet 12 on the back layer L4 side. The through hole groups 9a and 9b also function as thermal vias.

  A heat radiation pattern is formed on the back surface layer L4 so as to correspond to the coil patterns 4a and 4b of the inner layers L2 and L3. The coil patterns 4a and 4b and the heat radiation pattern are connected to the heat radiation pins 7a to 7d, the through holes 8d, and the lands 8c. May be thermally connected. Thereby, the heat generated from the coil patterns 4a and 4b is diffused widely to the heat radiation pattern of the back surface layer L4 via the heat radiation pins 7a to 7d, and the efficiency is transferred from the surface of the heat radiation pattern to the heat sink 10 via the insulating sheet 12. It can be communicated well to further dissipate heat.

  According to the above embodiment, a series of coils of the magnetic device 1 and the substrate 3 are constituted by the coil patterns 4 a and 4 b formed on the substrate 3 and the external coil 11 surface-mounted on the substrate 3. For this reason, even if it is difficult to secure a large number of turns for reasons such as increasing the width of the coil patterns 4a and 4b in a limited area of the substrate 3 (around the convex portion 2m of the core 2a), the external By connecting the coil 11 to the coil patterns 4a and 4b, the number of turns of the coil can be easily increased. Further, the external coil 11 can be easily attached to the substrate 3 by surface mounting. Therefore, the substrate 3 can be easily manufactured even if the number of turns of the coil is increased.

  In addition, since the external coil 11 is surface-mounted on the substrate 3, the surface layer L1 of the substrate 3 can normalize a large current by increasing the cross-sectional area of the external coil 11 without increasing the thickness of the conductor. Can be shed. Further, by reducing the thickness of the conductor of the surface layer L1, other electronic components and electric circuits of the switching power supply device 100 can be mounted with high density. Therefore, the thickness of the conductor is the same in each part of the surface layer L1, the number of manufacturing steps of the surface layer L1 can be reduced, and the manufacture of the substrate 3 can be facilitated.

  Further, when a large current flows through the coil, the heat generated from the external coil 11 can be dissipated to the surroundings. Further, the heat generated from the coil patterns 4a and 4b can be transmitted to the front surface layer L1 and the back surface layer L4 by the heat radiating pins 7a to 7d and can be radiated to the surroundings. Therefore, it is possible to suppress an increase in temperature of the substrate 3 due to heat generated from the coils of the magnetic device 1 and the substrate 3.

  Moreover, in the said embodiment, the thickness of the conductor of the inner layers L2 and L3 of the board | substrate 3 is thickened, and coil pattern 4a, 4b is formed in this inner layer L2, L3. For this reason, it is possible to increase the thickness of the coil patterns 4a and 4b, ensure a cross-sectional area to some extent, and allow a large current to flow normally.

  Moreover, in the said embodiment, in the board | substrate 3, the surface electrode 8i, the wiring pattern 4c, the pad 8f, the external coil 11, the pad 8e, the relay pattern 4d, the through hole group 9a, the coil pattern 4a, the through hole group 9b, and the coil pattern 4b The through hole 8o with the conductive pin 6o and the surface electrode 8o are connected in series in this order. The patterns 4c and 4d, the pads 8f and 8e, the through-hole groups 9a and 9b, and the through-hole 8b are arranged so as not to overlap each other on the plate surface of the substrate 3. The external coil 11 is surface-mounted so as not to overlap the surface electrode 8o, the conductive pin 6o, the through hole 8b, and the through hole group 9b on the plate surface of the substrate 3. For this reason, a series of coil current paths are reliably formed, and a large current can be normally passed from the one surface electrode 8i to the other surface electrode 8o through the external coil 11 and the carp patterns 4a and 4b.

  In the above embodiment, the external coil 11 and the coil patterns 4a and 4b and the surface electrode 8o in the different layers L1 to L3 are connected to each other by the through-hole groups 9a and 9b penetrating the substrate 3 and the through-holes 8o with the conductive pins 6o. Since it is connected, the reliability of electrical connection can be improved. Further, since the connection means that penetrates the substrate 3 is easier to be provided on the substrate 3 than the connection means that does not penetrate the substrate 3, the production of the substrate 3 can be made easier.

  Further, for example, as shown in FIG. 11, when the annular external coil 18 is formed from the metal strip 19 so that the plate surface direction of the metal strip 19 and the radial direction of the circumferential portion 18a are parallel to each other, It is difficult to punch a plurality of external coils 18 from the same region in the length direction of the material 19. Further, when punched as shown in FIG. 11, the waste of the metal strip 19 increases.

  However, in the above embodiment, the coil metal plate 11 'is bent to form the external coil 11 in a cylindrical shape. For this reason, it is possible to form a plurality of external coils 11 by punching a plurality of coil metal plates 11 ′ from the same region in the length direction of the metal strip 13 and bending each coil metal plate 11 ′. it can. Therefore, waste of the metal strip 13 can be reduced and the external coil 11 can be efficiently manufactured.

  In the present invention, various embodiments other than those described above can be adopted. For example, in the above embodiment, an example in which one turn of the external coil 11 is surface-mounted on the surface layer L1 of the substrate 3 and one turn of the coil patterns 4a and 4b is formed on the inner layers L2 and L3, respectively. The invention is not limited to this. The number of turns of the external coil or coil pattern may be one or two or more. Further, the number of turns may be different between the external coil and the coil pattern of each layer. The coil pattern may be formed on at least one layer of the substrate.

  In addition, an external coil may be surface-mounted on the back layer of the substrate, or a coil pattern may be formed. Furthermore, you may provide both an external coil and a coil pattern in the surface layer or back surface layer of a board | substrate. In this case, for example, the thickness of the conductor on the front surface layer or the back surface layer is reduced to form a thin coil pattern, and an external coil having a predetermined cross-sectional area is connected in parallel to the coil pattern. It is good to implement. Thereby, a predetermined large current can be normally passed through the external coil and the coil pattern while facilitating the manufacture of the substrate. Also, other electronic components and electric circuits can be mounted at a high density on the surface layer or the back surface layer where the conductor is thin.

  In the above embodiment, an example has been shown in which one surface electrode 8i on the surface layer L1 of the substrate 3 is the starting point of the coil current path, and the other surface electrode 8o is the end point of the coil current path. The present invention is not limited to this. Any one of the surface electrodes 8i in the surface layer L1 and the back surface layer L4 is used as a starting point or an end point of the current path of the coil, and any one of the surface electrodes 8o in the surface layer L1 and the back surface layer L4. May be the end point or starting point of the current path of the coil.

  Alternatively, the surface electrode 8i, the conductive pin 6i, and the wiring pattern 4c may be omitted, and the pad 8f on the surface layer L1 may be used as an input surface electrode. In this case, wiring may be provided as appropriate so as to be connected from the pad (surface electrode) 8f to the diodes D1 and D2 in FIG. Further, the relay pattern 4d may be omitted, and a through hole group for connecting the external coil 11 and the coil pattern 4a may be provided in the pad 8e.

  Moreover, although the example which electrically connected the patterns 4d-4f, 4a, and 4b in different layers L1-L3 by the through-hole groups 9a and 9b was shown in the above embodiment, this invention is limited only to this. Not what you want. In addition to this, patterns of different layers may be connected to each other by other connecting means such as a single through hole, a pin, or a terminal.

  In the above embodiment, the coil pattern 4b of the inner layer L3 and the surface electrode 8o of the surface layer L1 are electrically connected by the through hole 8b and the conductive pin 6o. However, the present invention is not limited thereto. It is not limited. In addition to this, for example, the conductive pin may be omitted, and the coil pattern of the inner layer and the output surface electrode may be electrically connected by a single or a plurality of through holes.

  Moreover, in the above embodiment, as shown in FIG. 8, the example which used the external coil 11 with a flat upper surface was shown, However, This invention is not limited only to this. In addition to this, for example, as shown in FIG. 10, an external coil 14 having irregularities on the circumference may be used. Thereby, since the surface area of the external coil 14 becomes large, the heat generated from the external coil 14 can be more easily radiated. As another example, unevenness may be provided on the lower surface (surface on the substrate side) of the external coil, or unevenness may be provided on both the lower surface and the upper surface (surface opposite to the substrate) of the external coil. Furthermore, unevenness may be provided on the circumferential surface of the external coil so as to deviate from the current path of the external coil.

  Moreover, although the example which combined the I-shaped lower core 2b with the E-shaped upper core 2a was shown in the above embodiment, this invention is applicable also to the magnetic device which combined two E-shaped cores. it can.

  Furthermore, in the above embodiment, the present invention is applied to the magnetic device 1 used as the choke coil L of the smoothing circuit 55 in the vehicle switching power supply device 100 and the substrate 3 on which each part of the switching power supply device 100 is mounted. An example was given. However, the present invention can be applied to, for example, a magnetic device used as the transformer 53 (FIG. 1) or a substrate on which a part of the switching power supply device 100 is mounted. Further, the present invention can also be applied to a magnetic device used in a switching power supply device for electronic equipment other than a vehicle, and a substrate for the magnetic device.

DESCRIPTION OF SYMBOLS 1 Magnetic device 2a Upper core 2b Lower core 3 Coil integrated printed board 4a, 4b Coil pattern 4c Wiring pattern 4d Relay pattern 6o Conductive pin 8b Through hole 8e, 8f Pad 8i, 8o Surface electrode 9a, 9b Through hole group 11, 14 External coil L1 Surface layer L2, L3 Inner layer L4 Back layer

Claims (8)

In a coil-integrated printed board in which a coil pattern is formed by printing on one or more layers,
An external coil surface-mounted on the coil-integrated printed circuit board;
The coil pattern and the external coil are wound around a common core that penetrates the coil-integrated printed board.
One end of the said coil pattern and one end of the said external coil are electrically connected, The coil integrated type printed circuit board characterized by the above-mentioned. In the coil integrated type printed circuit board according to claim 1,
A pair of surface electrodes for inputting and outputting power;
One coil of the pair of surface electrodes is electrically connected to the other end of the external coil, and the other surface electrode is electrically connected to the other end of the coil pattern. Integrated printed circuit board. The coil-integrated printed circuit board according to claim 2,
The coil pattern is formed in an inner layer that is not exposed to the outside,
The external coil and the pair of surface electrodes are provided on the same surface layer,
First connection means for electrically connecting the one surface electrode and the other end of the external coil;
A second connecting means penetrating the coil-integrated printed board and electrically connecting one end of the external coil and one end of the coil pattern;
A third connecting means that penetrates through the coil-integrated printed board and electrically connects the other surface electrode and the other end of the coil pattern;
Each of the connection means is arranged so as not to overlap each other on the plate surface of the coil-integrated printed board. The coil-integrated printed circuit board according to claim 3,
The external coil is surface-mounted so that it does not overlap the other surface electrode and the third connecting means on the plate surface of the coil-integrated printed board. In the coil integrated type printed circuit board according to claim 3 or 4,
The coil pattern is formed in a plurality of layers,
A fourth connecting means that penetrates the coil-integrated printed board and electrically connects the coil patterns in different layers;
The fourth connection means is arranged so as not to overlap the first connection means, the second connection means, and the third connection means on the plate surface of the coil-integrated printed board. Coil-integrated printed circuit board. The coil-integrated printed circuit board according to any one of claims 1 to 5,
The coil according to claim 1, wherein the external coil is formed in a cylindrical shape by bending a metal plate. The coil-integrated printed circuit board according to any one of claims 1 to 6,
A coil-integrated printed circuit board, wherein irregularities are provided on the circumference of the external coil. A coil-integrated printed circuit board according to any one of claims 1 to 7,
A core made of a magnetic material and penetrating the coil-integrated printed board,
The magnetic device, wherein the coil pattern is formed on the coil-integrated printed board and the external coil is surface-mounted so as to be wound around the core.

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