JP2014179402A - Magnetic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic device which can improve radiation performance of a multilayer substrate in which coil patterns are provided in a plurality of layers, respectively.SOLUTION: A magnetic device 1 comprises: a core 2a; openings 3m, 3L, 3r into which the core 2a is inserted; a multilayer substrate 3 having a surface layer L1, a rear face layer L3 and an inner layer L2 arranged between the layers L1, L3; coil patterns 4a-4c which are provided on the respective layers L1-L3 of the substrate 3 and wound around the core 2a; through holes 9a, 9b provided on the substrate 3, for connecting the coil patterns 4a-4c arranged on different layers L1-L3 with each other; and a plurality of terminals 6i, 6o provided through the substrate 3 so as to penetrate, for inputting/outputting power with respect to the coil patterns 4a-4c. The magnetic device 1 comprises radiation patterns 4 t, 4 t, 5 s, 4 t, 5 snear the terminals 6i, 6o of the surface layer L1 and the rear face layer L3, which spread in a board surface direction of the substrate 3.

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 core is inserted in the opening part provided in the board | substrate. A board | substrate consists of a multilayer substrate which has the surface layer provided in the surface and the back surface, and the inner layer provided among them. A coil pattern is formed on each layer so as to be wound around the core. In order to connect the coil patterns of different layers, a connection portion made of a through hole, a pin, or the like is provided on the substrate. Further, in order to input / output electric power to / from the coil pattern, a terminal portion including pins and through holes is provided on the substrate. These energization pins and through holes penetrate the substrate.

  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.

  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 a coil pattern of a predetermined layer of a substrate is expanded 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 Reissue WO2010 / 026690 JP-A-8-69935 JP 2008-177516 A

  If the coil pattern is made thin in order to achieve the predetermined performance of the coil, the number of turns of the coil can be increased by winding the coil pattern many times on each layer without enlarging the substrate. Even if the number of layers of the substrate is increased, the number of turns of the coil can be increased. However, when the coil pattern is thinned, the amount of heat generated in the coil pattern is increased. When the number of layers of the substrate is increased, heat is easily trapped on the substrate, and the temperature of the substrate is easily increased in all cases.

  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 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 includes a core, an opening into which the core is inserted, a surface layer provided on the front surface, a back surface layer provided on the back surface, and a multilayer substrate having an inner layer provided between these layers. A coil pattern provided in a plurality of layers of the substrate and wound around the core; a connection portion provided in the substrate for connecting the coil patterns in different layers; and provided so as to penetrate the substrate; And a plurality of terminal portions for inputting / outputting electric power to / from the coil pattern. And the heat dissipation pattern which spreads in the board surface direction of a board | substrate is provided in the vicinity of the terminal part of the surface layer of a board | substrate, and a back surface layer.

  As a result, the heat of the multilayer substrate having the coil pattern provided on the plurality of layers is transmitted to the heat radiation pattern provided on the front surface layer and the back surface layer of the substrate by the terminal portion penetrating the substrate, and diffused to the heat radiation pattern. The heat can be dissipated from the surface of the heat radiation pattern. That is, the power input / output terminal portion can also be used as a heat dissipation path to facilitate heat dissipation of the substrate, and the heat dissipation performance of the substrate can be improved.

  According to the present invention, in the magnetic device, the coil pattern is formed in a strip shape, wound around each layer of the substrate a plurality of times, and the terminal portion is connected to the coil pattern in the surface layer and the first terminal portion. And a second terminal portion connected to the coil pattern on the back surface layer.

  In the present invention, in the magnetic device, the heat radiation pattern provided in the vicinity of the first terminal portion of the back surface layer is connected to the first terminal portion, and the coil pattern and the second terminal provided in the back surface layer. It may be insulated from the part.

  In the present invention, in the magnetic device, the heat radiation pattern provided in the vicinity of the second terminal portion of the back surface layer may be connected to the coil pattern and the second terminal portion provided in the back surface layer.

  In the present invention, in the above magnetic device, the terminal portion may be made of a copper pin having a diameter larger than that of the connection portion.

  Furthermore, in this invention, you may provide a heat radiator in the back surface layer side in the said magnetic device.

  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 XX sectional drawing 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 inputting / outputting electric power 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 to 6 are cross-sectional views of the magnetic device 1, in which FIG. 4 shows a cross section taken along line XX of FIG. 3, FIG. 5 shows a cross section taken along line YY of FIG. -Z section is shown.

  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 in a line 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. 5, 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 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 surface layer L1 as shown in FIG. 3A is provided on the surface of the substrate 3 (upper surface in FIGS. 2 and 4 to 6). A back surface layer L3 as shown in FIG. 3C is provided on the back surface of the substrate 3 (the bottom surface in FIGS. 2 and 4 to 6). As shown in FIGS. 4 to 6, an inner layer L2 as shown in FIG. 3B is provided between the front surface layer L1 and the back surface 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 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, 3, and 5, the central protrusion 2m of the core 2a is inserted into one opening 3m at the center, and the core 2a is inserted into the left and right openings 3L and 3r. Left and right convex portions 2L, 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 back surface 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 surface side of the substrate 3 and screwed into the screw holes 10 a of the heat sink 10. Thereby, as shown in FIGS. 4-6, the heat sink 10 is fixed to the back surface layer L3 side of the board | substrate 3 in the proximity | contact 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. The through holes 8a, 8d, 9a, 9b, the terminals 6i, 6o, and the pins 7a-7d are provided so as to penetrate the substrate 3 (see FIGS. 4 and 6).

  Of the pair of through holes 8a, the terminal 6i is embedded in one through hole 8a, and the terminal 6o is embedded in the other through hole 8a. The pair of terminals 6i and 6o are made of copper pins. Around the terminals 6i and 6o of the front surface layer L1 and the back surface layer L3, pads 8b of through holes 8a are provided. 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, as shown in FIG. The terminals 6i and 6o are examples of the “terminal portion” in the present invention.

Each layer L1~L3 substrate 3, the coil pattern 4a~4c and the heat dissipation pattern _{4t 0 ~4t 6, 5s 0 ~5s} 9 is provided. Each pattern _{4a~4d, 4t 0 ~4t 6, 5s} 0 ~5s 9 is made of a copper foil. Each pattern _4a of the surface layer L1, the _{4t 0 ~4t 2, 5s 0 ~5s} 2 of surface, insulating treatment is applied.

  The coil patterns 4 a to 4 c are formed in a strip shape parallel to the plate surface direction of the substrate 3. The width, thickness, and cross-sectional area of the coil patterns 4a to 4c suppresses 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 surface layer L1 and one end of the coil pattern 4b of the inner layer L2 are connected by a plurality of through holes 9a. The other end of the coil pattern 4b in the inner layer L2 and one end of the coil pattern 4c in the back layer L3 are connected by a plurality of through holes 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 diameters of the terminals 6i and 6o are larger than the diameters of the through holes 9a and 9b. The through holes 9a and 9b are an example of the “connecting portion” in the present invention.

  Small patterns 4d are provided around the through hole 9b in the surface layer L1 and around the through hole 9a in the back surface 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 surface layer L1 is subjected to insulation processing.

  As shown in FIG. 3A, the other end of the coil pattern 4a of the surface 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 back surface layer L3 is connected to the terminal 6i through the pad 8b and the through hole 8a. The terminal 6o is an example of the “first terminal portion” in the present invention, and the terminal 6i is an example of the “second terminal portion” in the present invention.

  As described above, the coil patterns 4a to 4c of the substrate 3 are the back surface layer L3, and after the first and second times are wound around the convex portion 2m from the terminal 6i which is the starting point, via the through hole 9b, Connected to the inner layer L2. Next, the coil patterns 4a to 4c are the inner 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 surface layer L1 via the through holes 9a. And the coil patterns 4a-4c are the surface 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 is also input from the terminal 6i, flows in the order of the coil pattern 4c, the through hole 9b, the coil pattern 4b, the through hole 9a, and the coil pattern 4a, and then is output from the terminal 6o. Is done.

As shown in FIG. 3, heat radiation patterns 4 t _{0 to} 4 t ₆ and 5 s _{0 to} 5 s ₉ are provided in the empty areas of the layers L _{1 to} L 3 of the substrate 3. Among them, the heat radiation patterns 4 t _{0 to} 4 t ₆ are provided integrally with the coil patterns 4 a to 4 c by spreading a part of the coil patterns 4 a to 4 c in the plate surface direction of the substrate 3. That is, each layer L1 to L3, the heat radiation pattern _4t 0 _{~4t 6} is connected to the coil patterns 4 a to 4 c.

The heat radiation patterns 5s _{0 to} 5s ₉ are provided separately from the coil patterns 4a to 4c in the respective layers L1 to L3 so as to spread in the plate surface direction of the substrate 3. Further, the heat radiation patterns 5s _{0 to} 5s ₉ are also separated. That is, each layer L1 to L3, the heat radiation pattern _5s 0 _{~5s 9} are insulated from each other, and are insulated against the coil pattern 4a~4c in the same layer.

Further, the patterns 4 a to 4 d, 4 t _{0 to} 4 t ₆ , and 5 s _{0 to} 5 s ₉ are insulated from the screw 11. As shown in FIGS. 3B and 3C, the shortest insulating region around the through hole 3a in the surface layer L1 is larger than the shortest insulating region around the through hole 3a in the inner layer L2 and the back surface layer L3. ing. This is because the head portion 11a having a diameter larger than that of the shaft portion 11b of the screw 11 is disposed on the surface layer L1 side of the substrate 3, so that the head layer 11a and the patterns 4a, 4d, 5s _{2 in the} vicinity of the head portion 11a and the heat dissipation This is to insulate the parts 4t _{0 to} 4t ₂ .

As shown in FIG. 3 (a), in the surface layer L1, in the vicinity of the terminal 6i, it is provided radiating pattern 4t _0. Through-holes 8a and pad 8b of the surrounding terminal 6i is insulated against heat radiation pattern 4t _0. Heat dissipation patterns 4t ₂ and 5s ₀ are provided in the vicinity of the terminal 6o. Through-holes 8a and pad 8b of the surrounding terminal 6o is connected to the heat radiation pattern 4t _2, it is insulated against heat radiation pattern 5s _0.

Further, in the surface layer L1, in the vicinity of the heat radiation pattern _4t 2, 5s _0, the heat radiation pattern 5s ₁ is provided. The heat radiation pattern 5s ₁ is insulated from the heat radiation patterns 4t ₂ and 5s ₀ . Heat dissipation patterns 4t ₁ and 5s ₂ are provided on the opposite side of the core 2a from the terminals 6i and 6o.

As shown in FIG. 3 (b), in the inner layer L2, in the vicinity of the terminal 6i, it is provided radiating pattern 5s _3. Through hole 8a of the peripheral and terminal 6i it is insulated against heat radiation pattern 5s _3. In the vicinity of the terminal 6o, it is provided radiating pattern 4t _3. Through hole 8a of the peripheral and terminal 6o it is insulated against heat radiation pattern 4t _3. Terminal 6i to the core 2a, and on the opposite side 6o, the heat radiation pattern _5s 4, 4t ₄ is provided.

As shown in FIG. 3 (c), the rear surface layer L3, in the vicinity of the terminal 6i, are provided radiating pattern 4t _5. Through-holes 8a and pad 8b of the surrounding terminal 6i is connected to the heat radiation pattern 4t _5. Heat dissipation patterns 5s ₉ and 4t ₆ are provided in the vicinity of the terminal 6o. Through-holes 8a and pad 8b of the surrounding terminal 6o is connected to the heat radiation pattern 5s _9, it is insulated against heat radiation pattern _4t 6, 4t ₅ and terminal 6i.

Further, the rear surface layer L3, in the vicinity of the heat radiation pattern 4t _5, are provided radiating pattern 5s _5. Radiating pattern 5s ₅ is insulated against heat radiation pattern 4t _5. In the vicinity of the heat radiation pattern 4t _6, the heat radiation pattern 5s ₇ is provided. Radiating pattern 5s ₇ is insulated from the heat radiation pattern 4t _6. On the opposite side to the terminals 6i and 6o of the core 2a, heat radiation patterns 5s ₆ and 5s ₈ are provided.

  Heat dissipation pins 7a to 7d are embedded in the plurality of through holes 8d, respectively. The heat radiation pins 7a to 7d are made of copper pins. The diameters of the heat radiation pins 7a to 7d are larger than the diameters of the terminals 6i and 6o and the through holes 9a and 9b.

  A pad 8c of a through hole 8d is provided around the heat radiation pins 7a to 7d of the surface layer L1 and the back surface 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. 6).

As shown in FIG. 3, the through-holes 8d and pads 8c of the ambient and the heat dissipation pins 7a, the heat radiation pattern 4t ₀ of the surface layer L1, the heat radiation pattern 5s ₃ of the inner layer L2, and the heat radiation pattern 5s ₅ is connected backside layer L3 Has been. A heat radiation pattern 5s ₁ of the surface layer L1, a heat radiation pattern 4t ₃ of the inner layer L2, and a heat radiation pattern 5s ₇ of the back surface layer L3 are connected by the heat radiation pins 7b and the surrounding through holes 8d and pads 8c.

The through-holes 8d and pads 8c of the ambient and the heat dissipation pins 7c, the heat radiation pattern 4t ₁ of the surface layer L1, the heat radiation pattern 5s ₆ of the heat dissipation pattern 5s _4, and the back surface layer L3 of the inner layer L2 is connected. The heat radiation pattern 7 s ₂ of the surface layer L 1, the heat radiation pattern 4 t ₄ of the inner layer L ₂ , and the heat radiation pattern 5 s ₈ of the back surface layer L 3 are connected by the heat radiation pins 7 d and the surrounding through holes 8 d and pads 8 c.

  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 surface layer L1, the heat of the substrate 3, for example, are spread to a conductor of heat dissipation patterns _{4t 0 ~4t 2, 5s 0 ~5s} 2, is radiated from the surface of the conductor. Further, the heat of the substrate 3 is transmitted through conductors penetrating the substrate 3 such as the radiation pins 7a to 7d, the terminals 6i and 6o, and the through holes 8d, 8a, 9a, and 9b, and the heat sink 10 via the insulating sheet 12. The heat is dissipated. The through holes 9a and 9b also function as thermal vias.

In particular, heat generated by the coil patterns 4a of the surface layer L1 is liable to be diffused to the heat radiation pattern _4t 0 _{~4t 2,} these patterns _4a, and is radiated from the surface of 4t 0 ~4t _2. The heat generated in the coil pattern 4a 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 ₆ and 5s of the other layers L2 and L3. ₉ is diffused. Then, the diffused heat is transmitted to the heat sink 10 through the insulating sheet 12 from the surfaces of the heat radiation patterns 5s ₅ , 5s ₆ , 5s ₉ of the back surface layer L3, the lower surfaces of the heat radiation pins 7a and 7c, and the lower surfaces of the terminals 6o. The heat sink 10 radiates heat.

In the inner layer L2, for example, the heat of the substrate 3 is diffused into conductors such as heat radiation patterns 4t ₃ , 4t ₄ , 5s ₃ , 5s _4, and the heat radiation pins 7a to 7d, terminals 6i and 6o, and through holes 8d, 8a and 9a. , along the conductor through the substrate 3, such as 9b, it is diffused to the heat radiation pattern _{4t 0 ~4t 2, 4t 5,} 4t 6, 5s 0 ~5s 2, 5s 5 ~5s 9 of the surface layer L1 and the back layer L3 The Then, the diffused heat, etc. or is radiated from the heat radiation pattern _{4t 0 ~4t 2, 5s 0 ~5s} 2 of the surface of the surface layer L1, the heat radiation pattern _4t 5 backside layer _L3, 4t _6, 5s 5 ~5s ₉ is transmitted to the heat sink 10 via the insulating sheet 12 and is radiated by the heat sink 10.

In particular, heat generated in the coil pattern 4b of the inner layer L2 is, the heat radiation pattern _4t 3, liable to be diffused to 4t _4, the pattern _4t 3, 4t ₄ from cooling fins 7b, 7d and down along these around the through-hole 8d The heat dissipation patterns 5s ₁ , 5s ₂ , 5s ₇ and 5s ₈ of the other layers L1 and L3 are diffused. The diffused heat is radiated from the surfaces of the heat radiation patterns 5s ₁ and 5s ₂ of the surface layer L1, or insulated from the surfaces of the heat radiation patterns 5s ₇ and 5s ₈ of the back layer L3 and the lower surfaces of the heat radiation pins 7b and 7d. The heat is transmitted to the heat sink 10 via the sheet 12 and is radiated by the heat sink 10.

In the backside layer L3, the heat of the substrate 3, for example, are spread to a conductor of heat dissipation patterns _{4t 5, 4t 6, 5s 5} ~5s 9, transmitted to the heat sink 10 from the conductor through the insulating sheet 12, the heat sink 10 The heat is dissipated. The heat of the substrate 3, for example, heat radiating fins 7a~7d and terminals 6i, down along 6o and the through hole 8d, 8a, 9a, the conductors passing through the substrate 3, such as 9b, the heat radiation pattern 4t ₀ of the surface layer L1 diffused into ~4t _{2, 5s} 0 ~5s _2, are radiated from such heat radiation pattern _{4t 0 ~4t 2, 5s 0 ~5s} 2 of surface.

In particular, heat generated in the coil pattern 4c of the back layer L3 is radiating pattern _4t 5, liable to be diffused to 4t _6, through the coil pattern 4c surface and heat radiation pattern _4t 5, 4t insulating sheet 12 from the surface of ₆ of the heat sink 10 and is radiated by the heat sink 10. Further, heat generated in the coil pattern 4c is along the terminal 6i and its surrounding through hole 8a, and is radiated from such as the surface of a surface or terminal 6i of the heat radiation pattern 4t ₀ of the surface layer L1.

According to the above embodiment, the heat of the substrate 3 provided with the coil patterns 4a to 4c on the layers L1 to L3 is transferred to the heat radiation pattern 4t provided on the surface layer L1 and the back surface layer L3 by the terminals 6i and 6o penetrating the substrate 3. _{0, 4t 2, 5s 0,} 4t 5, you can tell 4t 6, 5s _9. Then, heat is diffused to the heat radiation patterns 4t ₀ , 4t ₂ , 5s ₀ , 4t ₅ , 4t ₆ , 5s ₉ to dissipate heat from the surface of the heat radiation patterns 4t ₀ , 4t ₂ , 5s ₀ of the surface layer L1, or the back surface. Heat can be radiated from the surface of the heat dissipation pattern 4t ₅ , 4t ₆ , 5s ₉ of the layer L3 via the heat sink 10. That is, the power input / output terminals 6i and 6o can also be used as a heat dissipation path to facilitate heat dissipation of the substrate 3.

The coil patterns 4a, the heat generated in 4b, the heat-radiating fin 7a to 7d, tell radiating pattern _{4t 0, 4t 1, 5s 1} , 4t 2, 5s 5 ~5s 8 of the surface layer L1 and the back layer L3 Can be diffused. Then, heat can be radiated from the surface of the heat radiation patterns 4t ₀ , 4t ₁ , 5s ₁ , 4t ₂ of the surface layer L1, or can be radiated through the heat radiation patterns 5s _{5 to} 5s _{8 of} the back layer L3 or the heat sink 10. . Further, the heat generated in the coil pattern 4c of the back surface layer L3 can be radiated through the heat radiation patterns 4t ₅ , 4t ₆ , 5s _{5 to} 5s ₉ and the heat sink 10.

  Therefore, the heat dissipation performance of the multilayer substrate 3 can be improved. In this example, it is possible to improve the heat dissipation performance of the substrate 3 in which the coil pattern is wound six times on three layers.

  In addition, by widening the width of the strip-like coil patterns 4a to 4c, it is possible to easily dissipate heat from the surfaces of the coil patterns 4a to 4c while suppressing the amount of heat generated in the coil patterns 4a to 4c. Moreover, by winding the coil patterns 4a to 4c a plurality of times around the layers L1 to L3, the number of turns of the coil patterns 4a to 4c can be increased with the substrate 3 having a small number of layers.

Further, the heat radiation pattern 5s ₉ provided in the vicinity of the terminal 6o backside layer L3, connected to the terminal 6o, and insulates the coil pattern 4c and the terminal 6i backside layer L3. Therefore, the heat generated by the coil patterns 4a of the surface layer L1, not only dissipated from the surface of the heat dissipation patterns 4t ₀ ~4t ₂ of the surface or surface layer L1 of the coil pattern 4a, the rear surface layer by terminal 6o L3 The heat radiation pattern 5 s ₉ can be transmitted to the heat sink 10 to dissipate heat. It is also possible not to affect the current paths of the coil patterns 4a to 4c.

Further, the heat radiation pattern 4t ₅ provided in the vicinity of the terminal 6i of the back surface layer L3 is connected to the coil pattern 4c and the terminal 6i of the back surface layer L3. For this reason, the heat generated in the coil pattern 4c is not only radiated from the surface of the coil pattern 4c, but is also easily transmitted to the terminals 6i and the heat radiating pattern 4t ₅ and radiated from the surface of the heat radiating pattern 4t _5. Can do. Furthermore, heat transferred to the heat radiation pattern 4t ₀ of the surface layer L1 by the terminal 6i, it can also be radiated from the surface of the heat radiation pattern 4t _0.

Furthermore, the terminals 6i and 6o are comprised from the large diameter copper pin from the through holes 9a and 9b which connect coil pattern 4a-4c. Therefore, heat terminal 6i generated at each coil patterns 4 a to 4 c, the 6o, terminal 6i of the surface layer L1 and the back layer L3 of the substrate 3, the heat radiation pattern _4t 0 in the vicinity of _6o, 4t 2, _5s 0, 4t ₅ , 5s ₉ can be easily transmitted, and the heat dissipation performance can be further enhanced.

In the present invention, various embodiments other than those described above can be adopted. For example, in the above embodiment, the example in which the coil patterns 4a to 4c and the heat radiation patterns 4t _{0 to} 4t ₆ and 5s _{0 to} 5s ₉ are provided on all the layers L1 to L3 of the substrate 3 is shown. It is not limited to only. In a multilayer substrate, a coil pattern may be provided in a plurality of layers, and a heat radiation pattern may be provided so as to spread in the plate surface direction of the substrate 3 at least in the vicinity of the terminals 6i and 6o of the front surface layer and the back surface layer. Moreover, the coil pattern is not limited to the one wound around the central convex portion 2m of the core 2a, but may be one wound around a plurality of convex portions of the core. Further, the number of turns of the coil pattern in one layer may be one time or three times or more. However, it is preferable to set the number of turns of the coil pattern of each layer in consideration of the size of the substrate. Moreover, it is preferable to widen the width of the coil pattern in order to suppress the amount of heat generated in the coil pattern and to facilitate heat dissipation from the surface of the coil pattern.

  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.

  In the above embodiment, the example in which the through holes 9a and 9b are provided in the substrate 3 as connection portions has been described. However, the present invention is not limited to this. In addition to this, other connection parts such as terminals and pins may be provided on the substrate to connect the coil patterns of different layers.

  Moreover, although the example which provided the terminal 6i and 6o which consist of a copper pin as a terminal part in the board | substrate 3 was shown in the above embodiment, this invention is not limited only to this. In addition to this, for example, the terminals 6i and 6o may be omitted, and the through holes 8a and the pads 8b may be provided as terminal portions. And you may connect an electronic component and a circuit directly to these terminal parts. 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 the core 3 substrate 3m, 3L, 3r opening 4a~4c coil pattern _{4t 0,} 4t 2, 4t ₅ radiating pattern 5s _0, 5s ₉ radiating pattern 6i, 6o terminals 9a, 9b through hole 10 Heat sink L1 Surface layer L2 Inner layer L3 Back layer

Claims (6)

The core,
A multilayer substrate having an opening into which the core is inserted, a surface layer provided on the front surface, a back surface layer provided on the back surface, and an inner layer provided between these layers;
A coil pattern provided on a plurality of layers of the substrate and wound around the core;
A connecting portion provided on the substrate and connecting the coil patterns in different layers;
In a magnetic device comprising a plurality of terminal portions that are provided so as to penetrate through the substrate and that input and output power to the coil pattern,
A magnetic device, wherein a heat radiation pattern extending in the plate surface direction of the substrate is provided in the vicinity of the terminal portion of the front surface layer and the back surface layer of the substrate. The magnetic device according to claim 1.
The coil pattern is formed in a strip shape and wound around each layer of the substrate a plurality of times,
The terminal portion includes a first terminal portion connected to the coil pattern on the front surface layer and a second terminal portion connected to the coil pattern on the back surface layer. device. The magnetic device according to claim 2, wherein
The heat dissipation pattern provided in the vicinity of the first terminal portion of the back surface layer is connected to the first terminal portion, and the coil pattern and the second terminal portion provided in the back surface layer. A magnetic device characterized by being insulated. The magnetic device according to claim 2 or claim 3,
The magnetic device, wherein the heat radiation pattern provided in the vicinity of the second terminal portion of the back surface layer is connected to the coil pattern and the second terminal portion provided in the back surface layer. The magnetic device according to any one of claims 1 to 4,
The said terminal part consists of a copper pin larger diameter than the said connection part, The magnetic device characterized by the above-mentioned. The magnetic device according to any one of claims 1 to 5,
A magnetic device, wherein a heat radiator is provided on the back layer side.

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