JP6213979B2 - Magnetic device - Google Patents

Description

  The present invention relates to a magnetic device such as a choke coil or a transformer, which includes a core made of a magnetic material and a substrate on which a coil pattern is formed.

  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 Documents 1 to 6 disclose a magnetic device including a coil pattern in which a coil winding is formed on a substrate.

  In patent documents 1-5, the convex part of the core is inserted in the opening part provided in the board | substrate. The substrate has a plurality of layers, and a coil pattern is formed on each layer so as to be wound around the core. Coil patterns of different layers are connected by through holes or the like.

  In Patent Document 6, the substrate is composed of a pair of insulating layers and a magnetic layer sandwiched between the insulating layers. A coil pattern is formed on the magnetic layer. The coil pattern is wound a plurality of times in the plate surface and thickness direction of the substrate.

  When a current flows through the coil pattern, heat is generated from the coil pattern, and the temperature of the substrate rises. As a heat dissipation measure, in Patent Document 1, the coil pattern is spread over almost the entire area of each layer of the substrate. A radiator is attached to the end of the substrate.

  In Patent Document 3, a part of the coil pattern of a predetermined layer of the substrate is widened to provide a heat radiation pattern portion. Further, the lower substrate is protruded from the upper substrate, and a heat radiation pattern portion is provided on the protruding portion so as to directly touch the outside air. Furthermore, the surface direction position of the heat radiation pattern part of each layer is varied.

  In Patent Document 6, a heat-transfer through conductor that penetrates the magnetic layer and the lower insulating layer is provided inside the coil pattern, and a heat-dissipating conductor layer connected to the heat-transfer through conductor is provided on the lower surface of the substrate. ing. The through conductor for heat transfer and the conductive layer for heat dissipation are not connected to the coil pattern.

JP 2008-205350 A Japanese Unexamined Patent Publication No. 7-38262 Japanese Patent Laid-Open No. 7-86755 Republished patent WO2010 / 026690 JP-A-8-69935 JP 2008-177516 A

  In order to achieve the predetermined performance of the coil, the number of turns of the coil can be increased by forming a coil pattern in a plurality of layers of a multilayer substrate of three or more layers. However, the greater the number of coil patterns, the greater the amount of heat generated, and the greater the number of layers of the substrate, the easier the heat is trapped on the substrate, and the temperature of the substrate rises.

  In particular, in a magnetic device used in a DC-DC converter through which a large current flows, a large amount of current flows through the coil pattern, so that the amount of heat generated in each coil pattern increases and the temperature of the substrate increases. As a result, the characteristics of the magnetic device may vary and the performance may deteriorate. In addition, when an electronic component such as another IC chip is mounted on the same substrate, there is a risk of malfunction or destruction of the electronic component.

  The subject of this invention is providing the magnetic device which can improve the thermal radiation performance of the multilayer board | substrate with which the coil pattern was provided in the several layer.

A magnetic device according to the present invention is provided in a multilayer substrate having a core, an opening into which the core is inserted, one layer on the surface and a plurality of other layers, and a plurality of layers of the substrate. A coil pattern wound on the substrate and a current-carrying connection portion that is provided on the substrate and connects the coil patterns in different layers. A plurality of other layers provided with a coil pattern are provided with a heat dissipating part wider than the coil pattern by extending a part of each coil pattern. When projected onto the plate surface from the plate thickness direction, the projection area is arranged so as not to overlap with a part or the whole of the projection region. Moreover, it is further provided with the connection part for thermal radiation provided in the board | substrate and connecting each thermal radiation part to one layer. One layer of the substrate is provided with a heat radiation pattern having a planar extension corresponding to the heat radiation portion in the other layer, and the heat radiation patterns are separated from each other. And the corresponding thermal radiation part and thermal radiation pattern are each connected by the connection part for thermal radiation. Note that a multi-layer substrate is a substrate having three or more layers.

  Thereby, in a plurality of other layers of the substrate, the heat generated by the coil pattern can be diffused to each heat dissipating portion arranged so as not to overlap on the plate surface of the substrate, and can be widely dispersed on the substrate. Then, the heat can be transferred from each heat radiating portion to one layer on the surface by each heat radiating connection portion to be radiated. Therefore, it is possible to improve the heat dissipation performance of a multilayer substrate in which a coil pattern is provided in a plurality of layers.

  Moreover, in this invention, you may provide a heat radiator in the one layer side of a board | substrate in the said magnetic device.

  According to the present invention, in the magnetic device, the core has a plurality of convex portions arranged on a straight line parallel to the plate surface direction of the substrate, and is parallel to the plate surface direction of the substrate and perpendicular to the straight line. The connection part for electricity supply may be provided in the one side of the board | substrate in a direction, and the thermal radiation part may be provided in the other side.

  In the present invention, the magnetic device further includes a terminal portion for inputting / outputting electric power to / from the coil pattern, and the terminal portion may be provided on the one side of the substrate (on the energizing connection portion side). Good.

  Further, according to the present invention, in the above magnetic device, the core has three convex portions, and the opening of the substrate includes a through hole into which at least the central convex portion of the three convex portions is inserted, and the coil The pattern may be wound a plurality of times around the central convex portion in each layer of the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the magnetic device which can improve the thermal radiation performance of the multilayer board | substrate with which the coil pattern was provided in the several layer.

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 a top view of each layer of the board | substrate of FIG. It is YY sectional drawing of FIG. It is ZZ sectional drawing of FIG.

  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.

  In the switching power supply device 100 described above, the 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, terminals 6i and 6o for power input / output are provided.

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

  FIG. 2 is an exploded perspective view of the magnetic device 1. FIG. 3 is a plan view of each layer of the substrate 3 of the magnetic device 1. 4 and 5 are cross-sectional views of the magnetic device 1. FIG. 4 shows a YY cross section of FIG. 3, and FIG. 5 shows a ZZ cross section of FIG.

  As shown in FIG. 2, the cores 2 a and 2 b are configured by a pair of an E-shaped upper core 2 a and an I-shaped lower core 2 b. 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 on a straight line Q as shown in FIG. As shown in FIG. 2, the left and right protrusions 2L and 2r have a larger amount of protrusion than the center protrusion 2m.

  As shown in FIG. 4, the lower ends of the left and right convex portions 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 2 b is fitted into a recess 10 k (FIG. 2) 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 and is an example of the “heat radiator” of the present invention.

  The board | substrate 3 is comprised from the thick copper foil board | substrate with which the pattern was formed in each layer of the thin-plate-shaped base material which consists of an insulator with thick copper foil (conductor). In the present embodiment, other electronic components and circuits are not provided on the substrate 3, but when the magnetic device 1 is actually used in the switching power supply device 100 of FIG. 1, the magnetic device 1 and the switching power supply device are provided on the same substrate. 100 other electronic components and circuits are provided.

  A first layer L1 as shown in FIG. 3A is provided on the upper surface of the substrate 3 (the upper surface in FIGS. 2, 4 and 5). On the lower surface of the substrate 3 (the lower surface in FIGS. 2, 4 and 5), a third layer L3 as shown in FIG. 3C is provided. As shown in FIGS. 4 and 5, a second layer L2 as shown in FIG. 3B is provided between the first layer L1 and the third layer L3.

  That is, the substrate 3 is a multilayer substrate having a total of three layers L1, L2, and L3, that is, two surface layers L1 and L3 capable of forming a circuit and one inner layer L2. Note that a multi-layer substrate is a substrate having three or more layers. The third layer L3 is an example of “one layer” in the present invention, and the first layer L1 and the second layer L2 are examples of “other layer” in the present invention.

  The substrate 3 is provided with a plurality of openings 3m, 3L, and 3r. The opening 3m is formed of a large-diameter circular through hole, and the openings 3L and 3r are formed of notches. As shown in FIGS. 2 to 4, the central protrusion 2 m of the core 2 a is inserted into one opening 3 m at the center, and the left and right protrusions of the core 2 a are inserted into the openings 3 L and 3 r on the left and right. The parts 2L and 2r are respectively inserted.

  The substrate 3 is provided with two circular through holes 3a having a small diameter. As shown in FIG. 2, each screw 11 is inserted into each through hole 3a. The third layer L3 side of the substrate 3 is opposed to the upper surface of the heat sink 10 (the surface opposite to the fin 10f). Then, the screws 11 are passed through the through holes 3 a from the first layer L 1 side of the substrate 3 and screwed into the screw holes 10 a of the heat sink 10. Thereby, as shown in FIG. 4, the heat sink 10 is fixed to the third layer L3 side of the substrate 3 in the proximity state.

  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 FIG. 3, the substrate 3, through holes 8a, 8d, 9a, 9b, pads 8b, 8c, terminal 6i, 6o, pattern _{4a~4d, 4t 0 ~4t 6, 5s} 0 ~5s 9, and Conductors such as pins 7a to 7d are provided.

  Of the pair of large-diameter through holes 8a, one through hole 8a has a terminal 6i embedded therein, and the other through hole 8a has a terminal 6o embedded therein. The pair of terminals 6i and 6o are made of copper pins. A pad 8b of a through hole 8a is provided around the terminals 6i and 6o of the first layer L1 and the third layer L3. The pad 8b is made of copper foil. Copper plating is applied to the surfaces of the terminals 6i and 6o and the pad 8b. The lower ends of the terminals 6i and 6o are in contact with the insulating sheet 12 (not shown). The terminals 6i and 6o are examples of the “terminal portion” in the present invention.

Coil patterns 4 a to 4 c and heat radiation patterns 5 s _{0 to} 5 s ₉ are provided on each layer L _{1 to} L 3 of the substrate 3. Each pattern _4a~4d, 5s 0 ~5s ₉ is made of a copper foil. The surface of each pattern 4a, 5s _{0 to} 5s ₂ of the first layer L1 is subjected to insulation processing. The widths, thicknesses, and cross-sectional areas of the coil patterns 4a to 4c suppress the amount of heat generated in the coil patterns 4a to 4c 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 to 4c.

  As shown in FIG. 3, each of the coil patterns 4 a to 4 c is wound twice around the central convex portion 2 m in each layer L <b> 1 to L <b> 3. One end of the coil pattern 4a of the first layer L1 and one end of the coil pattern 4b of the second layer L2 are connected by a through hole 9a. The other end of the coil pattern 4b of the second layer L2 and one end of the coil pattern 4c of the third layer L3 are connected by a through hole 9b.

  That is, the through holes 9a and 9b connect the coil patterns 4a to 4c in the different layers L1, L2, and L3. Copper plating is applied to the surface of each through hole 9a, 9b. The inside of each through hole 9a, 9b may be filled with copper or the like. The through holes 9a and 9b are an example of the “connection portion for energization” in the present invention.

  Small patterns 4d are provided around the through holes 9b of the first layer L1 and around the through holes 9a of the third layer L3 in order to facilitate the formation of the through holes 9a and 9b. Each through-hole 9a, 9b and the small pattern 4d are connected. The small pattern 4d is made of copper foil. The surface of the small pattern 4d of the first layer L1 is subjected to insulation processing.

  As shown in FIG. 3A, the other end of the coil pattern 4a of the first layer L1 is connected to a terminal 6o through a pad 8b and a through hole 8a. As shown in FIG. 3C, the other end of the coil pattern 4c of the third layer L3 is connected to the terminal 6i through the pad 8b and the through hole 8a.

  The terminals 6i, 6o, the through holes 8a, 9a, 9b, and the small pattern 4d are parallel to the plate surface direction of the substrate 3 and perpendicular to the straight line Q in which the convex portions 2L, 2m, 2r of the core 2a are arranged. And provided on one side of the substrate 3 (above the straight line Q in FIG. 3).

  As described above, the coil patterns 4a to 4c of the substrate 3 are the third layer L3, and the first and second times are wound around the convex portion 2m from the starting terminal 6i, and then through the through hole 9b. , Connected to the second layer L2. Next, the coil patterns 4a to 4c are the second layer L2, and after the third and fourth turns are wound around the convex portion 2m, the coil patterns 4a to 4c are connected to the first layer L1 via the through hole 9a. And the coil patterns 4a-4c are the 1st layer L1, and after the 5th time and the 6th time are wound around the convex part 2m, they are connected to the terminal 6o which is an end point.

  As described above, the current flowing through the magnetic device 1 also flows in the order of the terminal 6i, the coil pattern 4c, the through hole 9b, the coil pattern 4b, the through hole 9a, the coil pattern 4a, and the terminal 6o.

As shown in FIG. 3, in the empty regions of the layers L1 to L3 of the substrate 3, a part of each of the coil patterns 4a to 4c is expanded to the outside of the winding circumference, so that it is wider than the coil patterns 4a to 4c. The heat radiating portions 4t _{0 to} 4t ₆ are provided. Each radiating portion _4t 0 _{~4t 6,} like the coil pattern 4a~4c made of copper foil. The surface of the heat radiating portion _4t 0 _{~4t 2} of the first layer L1, insulation processing is given.

As shown in FIG. 3 (a), in the first layer L1, the heat radiating portion _4t 0 _{~4t 2} is disposed within the plate surface of the substrate 3, respectively. As shown in FIG. 3B, in the second layer L2, the heat radiating portions 4t ₃ and 4t ₄ are arranged in the plate surface of the substrate 3, respectively. As shown in FIG. 3C, in the third layer L <b> 3, the heat radiating portions 4 t ₅ and 4 t ₆ are respectively arranged in the plate surface of the substrate 3.

Further, on the upper side than the core 2a in FIG. 3, the heat radiating portion 4t ₀ of the first layer L1 and the heat radiating portion 4t ₃ of the second layer L2, when projected from a thickness direction of the substrate 3 to the plate surface, the projection Arranged so as not to overlap in the entire area.

Further, on the upper side than the core 2a in FIG. 3, the heat radiating portion 4t ₂ of the first layer L1 and the heat radiating portion 4t ₆ of the third layer L3, if projected from a thickness direction of the substrate 3 to the plate surface, the projection It is arranged so that it does not overlap in part of the area. The heat radiating part 4t ₃ of the second layer L2 and the heat radiating part 4t ₅ of the third layer L3 are arranged so as not to overlap in the entire projection area when projected onto the plate surface from the thickness direction of the substrate 3. .

Further, on the lower side than the core 2a in FIG. 3, the heat radiating portion of the first layer L1 4t ₁ and the heat radiating portion 4t ₄ of the second layer L2, when projected from a thickness direction of the substrate 3 to the plate surface, Arranged so as not to overlap in the entire projection area.

The heat radiating portions 4t ₁ and 4t ₄ are provided on the opposite side of the straight line Q from the terminals 6i and 6o, the through holes 8a, 9a, and 9b. That is, the heat radiating portions 4t ₁ and 4t ₄ are provided on the other side of the substrate 3 (below the straight line Q in FIG. 3) in a direction perpendicular to the straight line Q.

Further, in each layer L1~L3 substrate 3, the free space in the periphery of the coil pattern 4a~4d and the heat radiating portion _4t 0 _{~4t 6,} the heat radiation pattern _5s 0 ~ having a planar spread these separately from 5s ₉ are provided. The heat radiation patterns 5s _{0 to} 5s ₉ are also separate bodies.

The heat radiation patterns 5s _{5 to} 5s _{9 in} the third layer L3 are provided corresponding to the heat radiation parts 4t _{0 to} 4t ₄ in the other layers L1 and L2. Specifically, the heat radiation pattern 5s ₅ of the third layer L3 corresponds to the heat radiating portion 4t ₀ of the first layer L1, the heat radiation pattern 5s ₆ of the third layer L3 corresponds to the heat radiating portion 4t ₁ of the first layer L1 , the heat radiation pattern 5s ₉ of the third layer L3 corresponds to the heat radiating portion 4t ₂ of the first layer L1. Further, the heat radiation pattern 5s ₇ of the third layer L3 corresponds to the heat radiating portion 4t ₃ of the second layer L2, the heat radiation pattern 5s ₈ of the third layer L3, corresponding to the heat radiation portion 4t ₄ of the second layer L2 Yes.

The heat radiation patterns 5s _{1 to} 5s ₄ in the first layer L1 and the second layer L2 are provided corresponding to the heat radiation parts 4t ₀ , 4t ₁ , 4t ₃ and 4t ₄ in the different layers L1 to L3. . Specifically, the heat radiation pattern 5s ₁ of the first layer L1 corresponds to the heat radiating portion 4t ₃ of the second layer L2, the heat radiation pattern 5s ₂ of the first layer L1 corresponds to the heat radiating portion 4t ₄ of the second layer L2 ing. Further, the heat radiation pattern 5s ₃ of the second layer L2 corresponds to the heat radiating portion 4t ₀ of the first layer L1, the heat radiation pattern 5s ₄ of the second layer L2, corresponding to the heat radiating portion 4t ₁ of the first layer L1 Yes.

  Heat dissipation pins 7a to 7d are embedded in the plurality of large-diameter through holes 8d, respectively. The heat radiation pins 7a to 7d are made of copper pins. A pad 8c of a through hole 8d is provided around the heat dissipation pins 7a to 7d of the first layer L1 and the third layer L3. The pad 8c is made of copper foil. Copper plating is applied to the surfaces of the heat radiation pins 7a to 7d and the pad 8c. The lower ends of the heat radiation pins 7a to 7d are in contact with the insulating sheet 12 (see FIG. 5). The heat radiation pins 7a to 7d and the through hole 8d are examples of the “heat radiation connection portion” in the present invention.

Through holes 8d of the ambient and the heat dissipation pins 7a penetrates the heat radiating portion 4t ₀ of the first layer L1, the heat radiation pattern 5s ₃ of the second layer L2, and the heat radiation pattern 5s ₅ of the third layer L3. Radiating portion 4t ₀ and the heat dissipation pattern _5s 3, 5s ₅ are connected by through holes 8d and pads 8c of the ambient and the heat dissipation pins 7a.

Through holes 8d of the ambient and the heat dissipation pins 7b extends through the heat radiation pattern 5s ₇ of the heat radiation pattern 5s _1, the heat radiation portion 4t ₃ of the second layer L2, and a third layer L3 of the first layer L1. The heat dissipating part 4t ₃ and the heat dissipating patterns 5s ₁ and 5s ₇ are connected by the heat dissipating pins 7b and the surrounding through holes 8d and pads 8c.

Through holes 8d of the ambient and the heat dissipation pins 7c penetrates the heat dissipating portion 4t ₁ of the first layer L1, the heat radiation pattern 5s ₄ of the second layer L2, and the heat radiation pattern 5s ₆ of the third layer L3. The heat dissipating part 4t ₁ and the heat dissipating patterns 5s ₄ and 5s ₆ are connected by the heat dissipating pins 7c and the surrounding through holes 8d and pads 8c.

The heat radiation pin 7d and the surrounding through hole 8d penetrate the heat radiation pattern 5s ₂ of the first layer L1, the heat radiation part 4t ₄ of the second layer L2, and the heat radiation pattern 5s ₈ of the third layer L3. The heat dissipating part 4t ₄ and the heat dissipating patterns 5s ₂ and 5s ₈ are connected by the heat dissipating pins 7d, the surrounding through holes 8d and the pads 8c.

And the heat radiating portion 4t ₂ of the first layer L1, and the heat radiation pattern 5s ₉ of the third layer L3, are connected by a through-hole 8a and the pad 8b of the surrounding terminal 6o. Through-holes 8a and pad 8b of the surrounding terminal 6o is other are insulated against heat radiation portion _{4t 0, 4t 1, 4t 3} ~4t 6 and the heat radiation pattern _5s 0 _{~5s 8.} Through-holes 8a and pad 8b of the surrounding terminal 6i, to the third layer is connected to the heat radiating portion 4t ₅ of L3, other heat radiating portion _4t 0 _~4t 4, _{4t 6} and the heat radiation pattern _5s 0 _{~5s 9} Insulated.

The screw 11 is insulated from the patterns 4 a to 4 d, 5 s _{0 to} 5 s ₉ and the heat radiating portions 4 t _{0 to} 4 t ₆ . As shown in FIGS. 3B and 3C, the shortest insulating region around the through hole 3a in the first layer L1 is shorter than the shortest insulating region around the through hole 3a in the second layer L2 and the third layer L3. Is getting bigger. This is because the head portion 11a having a larger diameter than the shaft portion 11b of the screw 11 is disposed on the first layer L1 side of the substrate 3, so that the head portion 11a and the patterns 4a, 4d, 5s _{2 in the} vicinity thereof in the first layer L1. the or radiating portion _4t 0 _{~4t 2} in order to insulate.

  Since a large current flows through the coil patterns 4a to 4c, the coil patterns 4a to 4c serve as heat generation sources, and the temperature of the substrate 3 rises.

In the first layer L1, the heat of the substrate 3, for example, are spread to a conductor of heat dissipation portion _4t 0 _{~4t 2} and heat radiation pattern _5s 0 _{~5s 2,} is radiated from the surface of the conductor. The heat of the substrate 3 is radiated by the heat sink 10 through the insulating sheet 12 through conductors that penetrate the substrate 3 such as the heat radiation pins 7a to 7d and the through holes 8d, 8a, 9a, and 9b. The through holes 9a and 9b also function as thermal vias.

Further, the heat generation of the coil pattern 4a of the first layer L1 is transmitted through the heat radiation pins 7a and 7c, the terminal 6o, and the surrounding through holes 8d and 8a, and the heat radiation patterns 5s _{3 to} 5s of the other layers L2 and L3. ₆ , 5s ₉ is diffused. The diffused heat is transmitted to the heat sink 10 through the insulating sheet 12 from the surface of the heat radiation pattern 5s ₅ , 5s ₆ , 5s ₉ of the third layer L3 and the lower surface of the heat radiation pins 7a and 7c. Heat is dissipated.

In the second layer L2, the heat of the substrate 3, for example, are spread to a conductor of heat dissipation portion _4t 3, 4t ₄ and the heat radiation pattern _5s 3, 5s _4, heat radiating fins 7a~7d and the through hole 8d, 9a, 9b, etc. Heat is radiated by the heat sink 10 through the insulating sheet 12 through the conductor penetrating the substrate 3.

Further, heat generation of the coil pattern 4b of the second layer L2 is radiation fins 7b, 7d and down along these around the through-hole 8d, radiating pattern _5s 1 of the other layers _{L1, L3, 5s 2, 5s} 7, 5s ₈ is diffused. The diffused heat is radiated from the surfaces of the heat radiation patterns 5s ₁ and 5s ₂ of the first layer L1, or the surfaces of the heat radiation patterns 5s ₇ and 5s ₈ of the third layer L3 and the lower surfaces of the heat radiation pins 7b and 7d. Then, the heat is transmitted to the heat sink 10 through the insulating sheet 12 and is radiated by the heat sink 10.

In the third layer L3, the heat of the substrate 3, for example, are spread to a conductor of heat dissipation portion _4t 5, 4t ₆ and the heat radiation pattern _5s 5 _{~5s 9} and the heat-radiating fin 7a to 7d, along the insulating sheet 12 from the conductor The heat sink 10 radiates heat. Further, the heat of the substrate 3 is transmitted to the heat sink 10 from the surface of the coil pattern 4 c and the heat radiation portions 4 t ₅ and 4 t ₆ to the heat sink 10 through the insulating sheet 12, and is radiated by the heat sink 10.

According to the above-described embodiment, the heat radiation portions 4t ₀ arranged so that the heat generated in the coil patterns 4a and 4b in the first layer L1 and the second layer L2 of the substrate 3 does not overlap on the plate surface of the substrate 3. is diffused into ~4t _4, it can be widely dispersed in the substrate 3. Then, the heat can be transmitted from the heat radiation portions 4t _{0 to} 4t ₄ to the third layer L3 through the heat radiation pins 7a to 7d and the through holes 8d, and can be radiated through the heat sink 10 adjacent to the layer L3. Further, the heat generated in the coil pattern 4c of the third layer L3 can also be dissipated through the heat sink 10.

  Therefore, the heat dissipation performance of the multilayer substrate 3 in which the coil patterns 4a to 4c are provided on the plurality of layers L1 to L3 can be improved. In this example, it is possible to improve the heat dissipation performance of the substrate 3 having six coil patterns wound in three layers.

Further, when the heat radiation portions 4t ₁ and 4t ₄ in the first layer L1 and the second layer L2 are projected onto the plate surface from the plate thickness direction of the substrate 3, they are arranged so as not to overlap in the entire projection region. Thus, the coil patterns 4a, the heat generated in 4b, is diffused to the heat radiating portion 4t _1, 4t _4, heat can be more widely dispersed on the substrate 3. Then, the heat can be transferred from the heat radiating portions 4t ₁ and 4t ₄ to the third layer L3 by the heat radiating pins 7c and 7d to be radiated. That is, the heat radiation paths of the coil patterns 4a and 4b of the first layer L1 and the second layer L2 can be divided to efficiently dissipate heat.

Further, through holes 9a, 9b and terminals 6i on one side of the substrate 3, which are parallel to the plate surface direction of the substrate 3 and perpendicular to the straight line Q in which the convex portions 2L, 2m, 2r of the core 2a are arranged, 6o is provided, and the heat radiating portions 4t ₁ and 4t ₄ are provided on the other side. Therefore, the heat radiating portions 4t ₁ and 4t ₄ can be easily provided on the other side of the substrate 3 so as to be widened so as not to overlap each other on the plate surface.

Further, since the through holes 9a and 9b and the terminals 6i and 6o transmit heat together with power to the different layers L1 to L3, heat easily accumulates in the region of the substrate 3 on the opposite side. However, by providing the heat radiating portions 4t ₁ and 4t ₄ and the heat radiating pins 7c and 7d there, the heat is diffused to the heat radiating portions 4t ₁ and 4t ₄ and transmitted to the third layer L3 by the heat radiating pins 7c and 7d. The heat can be dissipated through the heat sink 10.

Further, the third layer L3, provided the heat radiation pattern _5s 5 _{~5s 9} separately to correspond to the heat radiating portion _4t 1 _{~4t 4} in the other layers L1, L2, corresponding radiating portion _4t 1 _{~4t 4} And the heat radiation patterns 5s _{5 to} 5s ₉ are connected to the heat radiation pins 7a to 7d and the through holes 8d, respectively. Thus, each coil patterns 4a of the first layer L1 and the second layer L2, heat generated in 4b, is diffused by the heat radiating portion _4t 1 _{~4t 4} radiating pattern _5s 5 _{~5s 9,} the heat radiation pattern _5s 5 ~ Heat can be efficiently radiated from 5s ₉ through the heat sink 10 or the like.

In the present invention, various embodiments other than those described above can be adopted. For example, in the above embodiment, the coil patterns 4a to 4c, the heat radiating portions 4t _{0 to} 4t ₆ and the heat radiating patterns 5s _{0 to} 5s ₉ are provided on all the layers L1 to L3 of the substrate 3. The invention is not limited to this. In a multi-layer substrate having a plurality of layers, a heat dissipation pattern may be provided in at least one layer on the surface, and a coil pattern or a heat dissipation portion may be provided in at least two other layers. Further, the coil pattern is not limited to being wound around only the central convex portion 2m of the core 2a, but may be wound around a plurality of convex portions of the core.

  Moreover, although the opening part 3m of the board | substrate 3 consists of a through-hole, and the opening parts 3L and 3r showed the notch in the above embodiment, the present invention is not limited only to this. In addition to this, all the openings of the substrate may be constituted by through holes, or may be constituted by grooves or depressions. Further, only one opening may be provided in the substrate.

  Moreover, in the above embodiment, although the example which connected the coil patterns 4a-4c of the different layers L1-L3 by the through holes 9a and 9b was shown, this invention is not limited only to this. In addition to this, for example, other energization connection portions such as terminals and pins may be provided on the substrate to connect the coil patterns of different layers.

Further, in the above embodiment, the heat radiation portions 4t _{0 to} 4t ₆ and the heat radiation patterns 5s _{1 to} 5s ₉ of the different layers L1 to L3 are formed by the heat radiation pins 7a to 7d and the through holes 8d or the terminals 6i and 6o and the through holes 8a. Although an example of connection is shown, the present invention is not limited to this. In addition to this, for example, at least one of terminals, pins, and through-holes is provided on the substrate, and a heat radiation part of a different layer is connected to the surface layer, or a heat radiation part and a heat radiation pattern of different layers are connected. Also good.

  Moreover, although the example which provided the terminals 6i and 6o in the board | substrate 3 as a terminal part was shown in the above embodiment, the terminals 6i and 6o may be abbreviate | omitted and the through hole 8a and the pad 8b may be used as a terminal part. And you may connect an electronic component and a circuit directly to these terminal parts 8a and 8b. For example, in the case of the switching power supply device 100 shown in FIG. 1, the cathodes of the diodes D1 and D2 of the rectifier circuit 54 are connected to the terminal portions 8a and 8b (input side) of the coil pattern 4a by soldering. One end of the capacitor C of the smoothing circuit 55 and one end of a line connected to the output voltage detection circuit 59 and the output terminal T3 may be connected to the terminal portions 8a and 8b (output side) by soldering.

  Moreover, although the example which used the heat sink 10 was shown as a heat radiator in the above embodiment, this invention is not limited only to this, Other air-cooled type or water-cooled type heat radiators, or refrigerant | coolants You may use the radiator etc. which used. Moreover, you may use not only a metal radiator but the radiator formed, for example with resin with high heat conductivity. In this case, it is not necessary to provide the insulating sheet 12 between the radiator and the substrate, and the insulating sheet 12 can be omitted. Further, the radiator may be provided on both sides of the substrate or may be omitted.

  Moreover, although the example using a thick copper foil board | substrate was shown in the above embodiment, this invention is not limited only to this, A general resin-made printed boards, metal boards, etc. Other substrates may be used. In the case of a metal substrate, an insulator may be provided between the base material and the coil pattern.

  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, although the example which applied this invention to the magnetic device 1 used as the choke coil L of the smoothing circuit 55 in the switching power supply device 100 for vehicles in the above embodiment was given, as the transformer 53 (FIG. 1) The present invention can be applied to a magnetic device to be used. Further, the present invention can be applied to a magnetic device other than a vehicle, for example, used in a switching power supply device for electronic equipment.

1 magnetic device 2a on the core 2b under core 2m, 2L, 2r projections 3 substrate 3m, 3L, 3r opening 4a~4c coil pattern 4t ₀ ~4t ₆ radiating portion 5s ₀ ~5s ₉ radiating pattern 6i, 6o terminal 7a~ 7d Radiation pin 8d Through hole 9a, 9b Through hole 10 Heat sink L1 1st layer L2 2nd layer L3 3rd layer Q Straight line in which convex parts are arranged

Claims (5)

The core,
A multilayer substrate having an opening into which the core is inserted, and one layer on the surface and a plurality of other layers;
A coil pattern provided on a plurality of layers of the substrate and wound around the core;
A connection portion for energization provided on the substrate and connecting the coil patterns in different layers;
A plurality of the other layers provided with the coil pattern is provided with a heat dissipating part wider than the coil pattern by extending a part of each coil pattern,
Among the heat radiating portions, the predetermined heat radiating portions are arranged so as not to overlap in a part or the whole of the projection region when projected onto the plate surface from the thickness direction of the substrate,
In the magnetic device further provided with a connection part for heat dissipation provided on the substrate and connecting each heat dissipation part to the one layer ,
The one layer of the substrate is provided with a heat spread pattern having a planar spread, corresponding to the heat dissipating part in the other layer, and the heat dissipating patterns are separated from each other,
The corresponding heat dissipation part and the heat dissipation pattern are respectively connected by the heat dissipation connection part. The magnetic device according to claim 1 .
A magnetic device comprising a radiator on the one layer side of the substrate. The magnetic device according to claim 1 or 2 ,
The core has a plurality of protrusions arranged on a straight line parallel to the plate surface direction of the substrate,
The current-carrying connection portion is provided on one side of the substrate and the heat dissipation portion is provided on the other side, which is parallel to the plate surface direction of the substrate and perpendicular to the straight line. Magnetic device. The magnetic device according to claim 3 .
A terminal portion for inputting / outputting electric power to / from the coil pattern;
The magnetic device, wherein the terminal portion is provided on the one side of the substrate. The magnetic device according to claim 3 or claim 4 ,
The core has three convex portions,
The opening of the substrate includes a through hole into which a convex portion at least in the center of the three convex portions is inserted,
The magnetic device, wherein the coil pattern is wound a plurality of times around the central convex portion in each layer of the substrate.

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