JP6261032B2 - Multilayer printed circuit boards, magnetic devices - Google Patents

Description

  The present invention relates to a multilayer printed board in which wiring patterns in different layers are electrically connected by through holes, and a magnetic device provided with the multilayer printed board.

  Switching power supply devices such as DC-DC converters (DC-DC converters) that switch high-voltage direct current to alternating current after switching to low-voltage direct current include magnetic devices such as choke coils and transformers. Is used.

  For example, Patent Document 1 and Patent Document 2 disclose a printed circuit board in which a coil pattern made of a conductor is formed in a plurality of layers, and a magnetic device including the circuit board. The coil pattern is made of a conductive metal foil such as a copper foil, similarly to other wiring patterns and conductors such as lands. In addition, coil patterns in different layers are electrically connected by a through hole penetrating the substrate, a copper pin, or the like. In Patent Document 2, coil patterns in different layers are electrically connected through a plurality of through holes. Inside the through hole, conductor plating such as copper is applied.

  Further, in Patent Document 3, after inserting a hooked connection pin into a through hole for electrically connecting wiring patterns in different layers of a substrate, soldering or filling with solder is performed. Thus, a technique for reducing electrical resistance is disclosed.

  Further, in Patent Document 4, a U-shaped terminal is inserted into a pair of grooves formed at the end of the substrate, the substrate and the terminal are soldered, and then the lower portion of the terminal is cut. The technique which makes the insertion operation of a terminal and the soldering operation | work of a terminal and a lead wire easy by making a terminal into two independent is disclosed.

JP 2010-109309 A JP 2002-280230 A JP 2002-111159 A Japanese Patent Laid-Open No. 11-121051

  For example, in a magnetic device used in a DC-DC converter, a large current flows through a coil. If the coil winding is composed of coil patterns formed on a plurality of layers of the substrate, in order to flow a large current, each coil pattern or an interlayer connection means for electrically connecting coil patterns in different layers is used. The electrical resistance must be reduced.

  As the interlayer connection means, for example, when a through hole in which a pin-like terminal is installed is adopted, in order to facilitate insertion of the terminal into the through hole, the outer diameter of the terminal is made smaller than the inner diameter of the through hole, It is necessary to increase the clearance between the through hole and the terminal to some extent. However, when it does so, since it will become easy to drop a terminal from a through hole, the operation | work which solders a terminal to a through hole will become difficult.

  An object of the present invention is to provide a multilayer printed board capable of easily forming an interlayer connecting means while reducing the electrical resistance of the interlayer connecting means for electrically connecting wiring patterns in different layers, and the multilayer printed board It is providing the magnetic device provided with.

In the multilayer printed board of the present invention, a wiring pattern is formed in a plurality of layers, a plurality of through holes with conductor plating applied to the inside are formed, and a wiring pattern of one layer and a wiring pattern of another layer are a plurality of A multi-layer printed circuit board electrically connected by through holes, a conductive terminal having a plurality of projecting portions projecting downward, and a connecting portion coupling the upper portions of these projecting portions, and a core made of a magnetic material Through-holes . The plurality of protruding portions of the conductive terminal are inserted into the plurality of through holes, respectively, and the protruding portions and the conductor plating of the through holes are soldered. In addition, the wiring pattern is composed of a coil pattern formed around the through hole so as to be wound around the core in a plurality of layers, and a coil pattern of one layer and a coil pattern of another layer are The plurality of through holes are electrically connected to each other by soldered conductive terminals after being inserted into the through holes.

  According to the above configuration, the interlayer connection means for electrically connecting the wiring patterns in different layers of the multilayer printed board is composed of a plurality of through holes, conductive terminals, and solder. Then, after the plurality of projecting portions of the conductive terminals are inserted into the plurality of through holes and soldered, the upper connecting portions of the projecting portions are left on the multilayer printed board without being cut. For this reason, the conductive volume of the interlayer connection means is increased, and the electrical resistance can be reduced.

  In addition, it is possible to easily insert the conductive terminal into the through hole by holding the connecting portion of the conductive terminal and inserting the plurality of protruding portions into the plurality of through holes at once. Furthermore, in order to facilitate the insertion of the plurality of protruding portions of the conductive terminal into the plurality of through holes, the outer diameter of the protruding portion is made smaller than the inner diameter of the through hole, and the gap between the through hole and the protruding portion is increased. Since the upper part of the protruding part is connected by the connecting part, the conductive terminal does not fall out of the through hole. For this reason, the soldering operation | work of the protrusion part of the conductive terminal with respect to a through hole can be made easy. Therefore, it is easy to form the interlayer connection means in the multilayer printed board.

  In the present invention, in the multilayer printed board, the conductive terminal may be formed in an inverted U shape.

  In the present invention, in the multilayer printed board, fins may be formed at the connecting portions of the conductive terminals.

  Furthermore, the magnetic device of the present invention includes the multilayer printed circuit board and a core penetrating the multilayer printed circuit board.

  Accordingly, it is possible to provide a magnetic device including a multilayer printed board that allows easy formation of interlayer connection means while reducing the electrical resistance of the interlayer connection means that electrically connects coil patterns in different layers. .

  According to the present invention, a multilayer printed board capable of easily forming an interlayer connecting means while reducing the electrical resistance of the interlayer connecting means for electrically connecting wiring patterns in different layers, and the multilayer printed board It becomes possible to provide the magnetic device provided with.

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 the surface layer of the A section in the multilayer printed circuit board of FIG. It is a top view of the 1st inner layer of the A section in the multilayer printed circuit board of FIG. It is a top view of the 2nd inner layer of the A section in the multilayer printed circuit board of FIG. It is a top view of the back surface layer of the A section in the multilayer printed circuit board of FIG. It is XX sectional drawing of FIGS. 3-6. It is YY sectional drawing of FIGS. It is ZZ sectional drawing of FIGS. FIG. 10 is a perspective view of the conductive terminal, the through hole, and the coil pattern of FIGS. 3 to 9. It is a perspective view of a conductive terminal, a through hole, and a wiring pattern according to another embodiment of the present invention. It is a perspective view of a conductive terminal, a through hole, and a wiring pattern according to another embodiment of the present invention. FIG. 6 is a perspective view of a conductive terminal according to another embodiment of the present invention. It is a perspective view of a through hole and a coil pattern as conventional interlayer connection means.

  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. An input electrode Ti for inputting power is provided on one end side of the choke coil L, and an output electrode To for outputting power is provided on the other end side.

  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. 3 to 6 are plan views of the respective layers L1 to L4 in part A of the multilayer printed board 3 (hereinafter simply referred to as "substrate 3") in FIG. Specifically, FIG. 3 is a plan view of the surface layer L1, FIG. 4 is a plan view of the first inner layer L2, FIG. 5 is a plan view of the second inner layer L3, and FIG. It is a top view of L4.

  7 to 9 are cross-sectional views of the magnetic device 1. Specifically, FIG. 7A shows the XX cross section of FIGS. 3 to 6, FIG. 8A shows the YY cross section, and FIG. ). Moreover, the ZZ cross section of FIGS. 3-6 is shown to Fig.9 (a), and the V section enlarged view of Fig.9 (a) is shown to FIG.9 (b). FIG. 10 is a perspective view of the conductive terminal, the through hole, and the coil pattern of FIGS.

  As shown in FIGS. 2 and 7, the cores 2 a and 2 b are configured by a pair of an upper core 2 a having an E-shaped cross section and a lower core 2 b 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. As shown in FIGS. 2 and 7, the left and right convex portions 2L and 2r have a larger amount of protrusion than the central convex portion 2m.

  As shown in FIG. 7, 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 7 k (FIG. 2) provided on the upper side of the heat sink 7. On the lower side of the heat sink 7, fins 7f are provided. The heat sink 7 is made of metal such as aluminum.

  The substrate 3 is composed of a printed circuit board in which a wiring pattern made of a conductive metal foil such as copper or a conductor such as a pad or a land is formed by etching on each layer of a thin base material made of an insulator. Yes. In FIG. 2, illustration of electronic components and electric circuits of the switching power supply device 100 of FIG. 1 is omitted on the substrate 3.

  A surface layer L1 as shown in FIG. 3 is provided on the surface of the substrate 3 (upper surface in FIGS. 2 and 7 to 9). A back surface layer L4 as shown in FIG. 6 is provided on the back surface of the substrate 3 (the bottom surface in FIGS. 2 and 7 to 9). As shown in FIGS. 7 to 9, inner layers L2 and L3 shown in FIGS. 4 and 5 are provided between the front surface layer L1 and the back surface layer L4. Among these, the one on the surface layer L1 side is called a first inner layer L2, and the one on the back layer L4 side is called a second inner layer L3. As described above, the substrate 3 has a total of four layers L1 to L4, which are the two outer layers L1 and L4 exposed to the outside and the two inner layers L2 and L3 that are not exposed to the outside.

  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 FIGS. 3 to 7, the central protrusion 2m of the core 2a is inserted into one opening 3m at the center, and the left and right protrusions of the core 2a are inserted into the openings 3L and 3r on the left and right. The parts 2L and 2r are respectively inserted. As shown in FIGS. 7-9, the heat sink 7 is being fixed to the back surface layer L4 side of the board | substrate 3 by fixing means, such as a screw which is not shown in figure. An insulating sheet 8 having heat conductivity is sandwiched between the substrate 3 and the heat sink 7. Since the insulating sheet 8 has flexibility, it is in close contact with the substrate 3 and the heat sink 7 without a gap.

  As shown in FIGS. 3 to 9, coil patterns 4 a to 4 d and lands 4 e to 4 j are formed on the plurality of layers L <b> 1 to L <b> 4 of the substrate 3 by using a thick metal foil. The coil patterns 4 a to 4 d 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 4d suppress the amount of heat generated in the coil patterns 4a to 4d 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 it is easy to radiate heat. The coil patterns 4a to 4d are a kind of wiring pattern.

  Further, a plurality of through holes 5a to 5c (see FIGS. 8 and 9) are formed in the substrate 3 as conductors that penetrate the substrate 3 in the thickness direction. Conductive plating 5p such as copper (see FIGS. 8B and 9B) is applied to the front side, the back side, and the inside of each through hole 5a to 5c. The diameters of the through holes 5a to 5c are the same.

  As shown in FIG. 3, the coil pattern 4a and the lands 4e, 4f formed on the surface layer L1 of the substrate 3 are separate from each other and are electrically insulated. Insulation is applied to the surfaces of the coil pattern 4a and the lands 4e, 4f. The coil pattern 4a is wound once around the through hole 3m and the convex portion 2m of the core 2a. One end of the coil pattern 4a is provided with a pair of through holes 5a. The other end (not shown) of the coil pattern 4a is connected to the input electrode Ti shown in FIG. The land 4e is provided with a pair of two through holes 5b. The land 4f is provided with a pair of through holes 5c.

  As shown in FIG. 4, the coil pattern 4b and the land 4g formed on the first inner layer L2 of the substrate 3 are separate from each other and are electrically insulated. The coil pattern 4b is wound once around the through hole 3m and the convex portion 2m of the core 2a. A through hole 5a is provided at one end of the coil pattern 4b, and a through hole 5b is provided at the other end. A through hole 5c is provided in the land 4g.

  As shown in FIG. 5, the coil pattern 4c and the land 4h formed in the second inner layer L3 of the substrate 3 are separate and electrically insulated. The coil pattern 4c is wound once around the through hole 3m and the convex portion 2m of the core 2a. A through hole 5b is provided at one end of the coil pattern 4c, and a through hole 5c is provided at the other end. A through hole 5a is provided in the land 4h.

  As shown in FIG. 6, the coil pattern 4d and the lands 4i and 4j formed on the back surface layer L4 of the substrate 3 are separate from each other and electrically insulated. The coil pattern 4d is wound once around the through hole 3m and the convex portion 2m of the core 2a. A through hole 5c is provided at one end of the coil pattern 4d. The other end (not shown) of the coil pattern 4d is connected to the output electrode To shown in FIG. A through hole 5a is provided in the land 4i. A through hole 5b is provided in the land 4j.

  The through hole 5a electrically connects the coil patterns 4a and 4b passing through different layers L1 to L4, and the coil patterns 4a and 4b and the lands 4h and 4i. The through hole 5b electrically connects the coil patterns 4b and 4c passing through different layers L1 to L4, and the coil patterns 4b and 4c and the lands 4e and 4j. The through hole 5c electrically connects the coil patterns 4c and 4d passing through different layers L1 to L4, and the coil patterns 4c and 4d and the lands 4f and 4g.

  Conductive terminals 6a, 6b, 6c made of copper or the like are installed in the through holes 5a, 5b, 5c, respectively. As shown in FIGS. 8 and 10A, each conductive terminal 6a, 6b, 6c is formed in an inverted U shape, and has two protruding portions 6t protruding downward, and upper portions of these protruding portions 6t. And a connecting portion 6u for connecting the two. The protruding part 6t and the connecting part 6u are integrally formed. The shapes of the conductive terminals 6a, 6b, and 6c are the same.

  Holding the connecting portion 6u of the conductive terminal 6a, from the upper side (surface layer L1 side) of the substrate 3, as shown in FIG. 10B, each protruding portion 6t of the conductive terminal 6a is respectively inserted into the pair of through holes 5a. insert. Then, as shown in FIG. 8 (b), each protrusion 6 t of the conductive terminal 6 a and the conductor plating 5 p of each through hole 5 a are joined by solder 9. Thereby, each protrusion 6t of the conductive terminal 6a is installed in each through hole 5a, and one end of the coil pattern 4a of the surface layer L1 and one end of the coil pattern 4b of the first inner layer L2 are electrically connected. (See FIG. 8 and FIG. 9A).

  Similarly, after gripping the connecting portion 6u of the conductive terminal 6b and inserting the protrusions 6t of the conductive terminal 6b into the pair of through holes 5b from above the substrate 3, the protrusions 6t and the The conductor plating 5p of the through hole 5b is joined with the solder 9. Thereby, each protrusion 6t of the conductive terminal 6b is installed in each through hole 5b, and the other end of the coil pattern 4b of the first inner layer L2 and one end of the coil pattern 4c of the second inner layer L3 are electrically connected. (See FIG. 9A).

  Similarly, after gripping the connecting portion 6u of the conductive terminal 6c and inserting the protrusions 6t of the conductive terminal 6c into the pair of through holes 5c from above the substrate 3, the protrusions 6t and the The conductor plating 5p of the through hole 5c is joined with the solder 9. Thereby, each protrusion 6t of the conductive terminal 6c is installed in each through hole 5c, and the other end of the coil pattern 4c of the second inner layer L3 and one end of the coil pattern 4d of the back surface layer L4 are electrically connected. (See FIGS. 9A and 9B).

  The through holes 5a, 5b, 5c, the conductive terminals 6a, 6b, 6c and the solder 9 constitute an interlayer connection means for electrically connecting the coil patterns 4a-4d in different layers L1-L4 of the substrate 3. Yes. The connecting portion 6u of each conductive terminal 6a, 6b, 6c functions as a part of the current-carrying path of the coil of the magnetic device 1 by leaving it on the surface side of the substrate 3 without cutting, and from the coil. It functions as a heat radiating part.

  As described above, the first coil of the magnetic device 1 is wound around the convex portion 2m by the coil pattern 4a of the surface layer L1 from the input electrode Ti of FIG. 1 as the starting point, as indicated by an arrow in FIG. Then, it is connected to the first inner layer L2 via the through hole 5a and the conductive terminal 6a. Next, in the first inner layer L2, as shown by an arrow in FIG. 4, the coil is wound around the convex portion 2m by the coil pattern 4b for the second time, and then passes through the through hole 5b and the conductive terminal 6b. , Connected to the second inner layer L3. Next, in the second inner layer L3, as shown by the arrow in FIG. 5, the coil is wound around the convex portion 2m by the coil pattern 4c for the third time, and then passes through the through hole 5c and the conductive terminal 6c. , Connected to the back layer L4. In the back surface layer L4, as shown by the arrow in FIG. 6, the coil is connected to the output electrode To in FIG. 1 as the end point after the coil pattern 4d is wound around the convex portion 2m for the fourth time. .

  That is, the input electrode Ti, the coil pattern 4a, the through hole 5a and the conductive terminal 6a, the coil pattern 4b, the through hole 5b and the conductive terminal 6b, the coil pattern 4c, the through hole 5c and the conductive terminal 6c, the coil pattern 4d, and the output electrode To A series of coil current paths connected in series in this order are formed in the substrate 3.

  According to the above embodiment, the interlayer connection means for electrically connecting the coil patterns 4a to 4d in the different layers L1 to L4 of the substrate 3 has two pairs of through holes 5a, 5b, and 5c, and an inverted U-shape. It comprises conductive terminals 6a, 6b, 6c and solder 9. Then, after the two projecting portions 6t of the respective conductive terminals 6a, 6b, 6c are inserted into the respective through holes 5a, 5b, 5c and soldered, the connecting portions 6u of the projecting portions 6t are cut off. And remains on the surface layer L1 side of the substrate 3. For this reason, the conductive volume of the interlayer connection means is increased, and the electrical resistance can be reduced.

  Specifically, as shown in FIG. 10, an interlayer connection means is constituted by a pair of through holes 5a, conductive terminals 6a, and solder 9 (FIG. 8B), so that the conventional example shown in FIG. Thus, the electrical resistance can be reduced to the same extent as in the case where the interlayer connection means is constituted by the five through holes 5a.

  Further, in the conventional example of FIG. 14, since the number of through holes 5a is large and the occupied area of the through holes 5a is large, it is difficult to route the coil pattern 4a 'and dispose the lands (not shown). There is a risk of increasing the size. However, in the said embodiment, the number of through-holes 5a-5c can be decreased, and the occupied area of the through-holes 5a-5c and the conductive terminals 6a-6c can be restrained small. Therefore, it is possible to facilitate the routing of the coil patterns 4a to 4c and the arrangement of the lands 4e to 4j and to reduce the size of the substrate 3.

  Further, in the above embodiment, the through holes 5a can be obtained by holding the connecting portions 6u of the conductive terminals 6a, 6b, 6c and inserting the two protruding portions 6t into the pair of through holes 5a, 5b, 5c, respectively. The work of inserting the conductive terminals 6a, 6b, 6c into 5b, 5c can be facilitated. Furthermore, in order to make it easier to insert the protruding portions 6t of the conductive terminals 6a, 6b, 6c into the pair of through holes 5a, 5b, 5c, the outer diameter of the protruding portion 6t is made smaller than the inner diameter of the through holes 5a, 5b, 5c. Even if the clearance between the through holes 5a, 5b, and 5c and the protruding portion 6t is increased, the conductive terminals 6a, 6b, and 6c are connected to the through holes 5a, 5b because the upper portions of the protruding portions 6t are connected by the connecting portions 6u. 5c will not fall out. For this reason, the soldering operation | work of the protrusion part 6t of the conductive terminals 6a, 6b, 6c with respect to the through holes 5a, 5b, 5c can be made easy. Therefore, it is easy to form interlayer connection means on the substrate 3 in which the coils of the magnetic device 1 are integrated.

  Furthermore, in the said embodiment, the connection part 6u of the electroconductive terminals 6a, 6b, 6c is left in the state exposed to the surface layer L1 side of the board | substrate 3 without cutting off. Further, the tips of the protruding portions 6 t of the conductive terminals 6 a, 6 b, 6 c protrude below the substrate 3. For this reason, the heat generated in the coil patterns 4a to 4d and the interlayer connection means during energization is dissipated from the connecting portions 6u of the conductive terminals 6a, 6b, and 6c and the tips of the protruding portions 6t, so that the temperature of the substrate 3 is increased. The rise can be suppressed.

  In the present invention, various embodiments other than those described above can be adopted. For example, in the above embodiment, two protruding portions 6t are formed in the conductive terminals 6a to 6c, and a pair of through holes 5a to 5c are formed so as to penetrate the plurality of coil patterns 4a to 4d to be connected. However, the present invention is not limited to this example. In addition to this, for example, as shown in FIG. 11 (a) and FIG. 12 (a), three or more protruding portions 6t are formed on the conductive terminals 6, 6 ′, and a plurality of wiring patterns 4, 4 ′ to be connected are formed. Three or more through holes 5, 5 ′ may be formed so as to penetrate. In that case, as shown in FIG. 11 (b) and FIG. 12 (b), after inserting the protruding portions 6t of the conductive terminals 6, 6 ′ into the through holes 5, 5 ′, respectively, What is necessary is just to solder the inner side conductor plating and the protrusion 6t.

  In the above embodiment, an example is shown in which one conductive terminal is used to electrically connect two coil patterns formed on different layers of the substrate. However, the present invention is limited to this. It is not a thing. In addition to this, for example, two or more conductive terminals may be used to electrically connect two coil patterns.

  Moreover, in the above embodiment, although the example which formed flat the connection part 6u of the conductive terminals 6a, 6b, 6c, 6, 6 'was shown, this invention is not limited only to this. In addition to this, for example, as shown in FIG. 13, fins 6s may be formed on the connecting portion 6u of the conductive terminal 6 ″. This increases the surface area of the connecting portion 6u of the conductive terminal 6 ″, so that The heat generated from the conductive terminal 6 ″ and the wiring pattern to be connected can be easily radiated.

  Moreover, although the example which formed each coil pattern 4a-4d in each layer L1-L4 of the 4-layer board | substrate 3 was shown in the above embodiment, this invention is not limited only to this. In addition to this, in a multilayer printed board, a coil pattern of one turn or two turns or more may be formed in a predetermined plurality of layers. In addition to the coil pattern, other wiring patterns may be formed in a plurality of layers, and the wiring patterns may be electrically connected by through holes, conductive terminals, and solder.

  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. In addition, the present invention can be applied to a magnetic device used in a switching power supply device for an electronic device other than a vehicle, a substrate for the magnetic device, or another substrate.

DESCRIPTION OF SYMBOLS 1 Magnetic device 2a Upper core 2b Lower core 3 Multilayer printed circuit board 3m 3L, 3r Through-hole 4, 4 'Wiring pattern 4a, 4b, 4c, 4d Coil pattern 5, 5' Through hole 5a, 5b, 5c Through hole 5p Conductor plating 6, 6 ', 6 "Conductive terminal 6a, 6b, 6c Conductive terminal 6t Protruding part 6s Fin 6u Connecting part 9 Solder L1 Surface layer L2 First inner layer L3 Second inner layer L4 Back surface layer

Claims (4)

The wiring pattern is formed in multiple layers,
Multiple through holes with conductor plating on the inside are formed,
In a multilayer printed board in which the wiring pattern of a certain layer and the wiring pattern of another layer are electrically connected by a plurality of the through holes,
A conductive terminal having a plurality of projecting portions projecting downward, and a connecting portion connecting the upper portions of these projecting portions ;
A through-hole through which a core made of a magnetic material passes ,
Wherein the plurality of protrusions of the conductive terminal is respectively inserted into the plurality of through-holes, and the protruding portion and the conductor plating of the through holes are soldered,
The wiring pattern is composed of a coil pattern formed around the through hole so as to be wound around the core in a plurality of layers.
The coil pattern of a layer and the coil pattern of another layer are electrically connected by the plurality of through holes and the conductive terminals soldered after being inserted into the through holes . A multilayer printed circuit board characterized by that. The multilayer printed circuit board according to claim 1,
The multilayer printed circuit board, wherein the conductive terminal is formed in an inverted U shape. In the multilayer printed circuit board according to claim 1 or 2,
A multi-layer printed circuit board, wherein fins are formed at the connecting portions of the conductive terminals. A multilayer printed board according to any one of claims 1 to 3 ,
A magnetic device comprising: the core penetrating the multilayer printed board.

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