JP2006165050A - Transformer integrated circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board integrally provided with a transformer that is easy in assembling work and satisfactory performance. <P>SOLUTION: The circuit board comprises a transformer coil pattern; a coil pattern for tertiary coil coil pattern disposed respectively on opposite sides of the transformer coil pattern; a middle slit 26 extending up to an internal region of the transformer coil pattern traversing the transformer coil pattern; transverse slits 27, 28 extending up to the internal region of the coil pattern traversing the tertiary coil pattern; a closed magnetic path core 29, disposed by inserting a central magnetic path leg 40 and outside magnetic path legs 41a, 41b, respectively through the middle slit 26 and the transverse slits 27, 28; and coil pattern conduction connection means 30 to 32 for conducting opposite coil pattern parts of divided parts of the respective coil patterns divided by the slits 26 to 28, in such a manner that it cross links the opposite coil pattern parts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transformer-integrated circuit board in which a coil pattern constituting a transformer is directly formed on a circuit board.

  FIG. 7A shows an example of the coil device in an exploded state, and FIG. 7B shows a cross-sectional view of the AA portion of the coil device shown in FIG. 7A. The coil device 1 shown in FIGS. 7A and 7B includes a circuit board 2, a coil pattern portion 3 formed on the circuit board 2, a pair of core members 4 (4a and 4b), and a core. The combination member 5 is included.

  The circuit board 2 is mounted with electronic components constituting the circuit and a circuit pattern is formed. In this example, the circuit board 2 is a multilayer board in which a plurality of boards are laminated. For example, the coil patterns 7 are arranged and formed on the plurality of boards constituting the circuit board 2 with the central axis being coaxial. The coil pattern portion 3 is constituted by the plurality of coil patterns 7. When the coil device 1 is a transformer device, at least one of the plurality of coil patterns 7 constitutes a primary coil, and the remaining constitutes a secondary coil.

  The core members 4a and 4b forming a pair are both produced by pressing and sintering a magnetic material powder such as ferrite, and a flat top plate portion 8 and a central portion of the top plate portion 8 and A cross section having core legs 9 (9a, 9b, 9c) erected on both right and left ends is an E-shaped core member having an E shape.

  The circuit board 2 is provided with core foot insertion through holes 10 (10 a, 10 b, 10 c) in the board part located at the center of the coil pattern part 3 and the board parts on both sides of the coil pattern part 3. The core feet 9 (9a, 9b, 9c) of the core members 4a, 4b are respectively inserted into the core foot insertion through holes 10a, 10b, 10c from the front and back sides of the circuit board 2, respectively. The core foot 9 of the core member 4a and the core foot 9 of the core member 4b on the back surface side are abutted.

  The core combination member 5 is formed by fitting a pair of core members 4a and 4b and is formed by bending a metal plate to form a base surface portion 12, a foot portion 13, and a claw portion. That is, the left and right ends of the base surface portion 12 covering the top plate portion 8 of the core member 4 are bent in the standing direction along the core feet 9 of the core member 4 to form the foot portions 13. Further, the claw portion 14 is formed by bending the distal end side of the foot portion 13 inward.

  The distance between the base surface portion 12 and the claw portion 14 is such that the core foot 9 of the core member 4a on the front surface side and the core foot 9 of the core member 4b on the back surface surface are in contact with each other. It is substantially equal to the distance h from the top surface 8a to the top surface 8a of the top plate portion 8 of the core member 4b. Therefore, by fitting the core combination member 5 and the core members 4a and 4b in the butted state, the base surface portion 12 and the claw portion 14 sandwich the left and right ends of the core members 4a and 4b in the butted state from both front and back sides. . At this time, the core members 4a and 4b are relatively movable in the front-rear direction (α direction shown in FIG. 7A). The length W in the front-rear direction of each core foot insertion through-hole 10 is longer than the width of the core foot 9 of the core member 4 so that the core member 4 can move in the front-rear direction.

  Such a coil device 1 is assembled as follows. For example, first, the core member 4a is disposed on the front surface side of the circuit board 2 on which the coil pattern portion 3 and the core leg insertion through hole 10 are formed, and the core member 4b is disposed on the back surface side. Then, each core foot 9 of the core member 4a on the front surface side is inserted through the corresponding core foot insertion through hole 10 from the front surface side of the circuit board 2. Similarly, each core foot 9 of the core member 4b on the back surface side is inserted into the corresponding core foot insertion through hole 10 from the back surface side of the circuit board 2. Thereby, the core foot 9 of the core member 4a on the front surface side and the core foot 9 of the core member 4b on the back surface side are abutted.

  Thereafter, the core combination member 5 is fitted onto the core members 4a and 4b in the butted state from above. At this time, the left foot portion 13a of the core combination member 5 is inserted into the left core foot insertion through hole 10a at a position outside the core foot 9 (9a) of the core member 4, and the right side of the core combination member 5 The leg portion 13b is inserted into the right core foot insertion through hole 10c at a position outside the core foot 9 (9c) of the core member 4.

  Accordingly, the pair of core members 4 a and 4 b are combined by the core combination member 5 and incorporated into the circuit board 2.

  Thereafter, the paired core members 4a and 4b are slid relative to each other in the front-rear direction, so that the contact portions of the core members 4a and 4b, that is, the end surfaces of the core feet 9 that are abutted with each other. Rub together. By thus rubbing the tip surfaces of the core feet 9 (core rubbing), the tip surfaces of the core feet 9 are polished and the tip surfaces of the core feet 9 are smoothed. Moreover, the dust which has entered between the front end surfaces of the core feet 9 is removed. By smoothing the tip surface of the core foot 9 by rubbing the core and removing dust between the tip surfaces of the core foot 9, the adhesion between the tip surfaces of the core feet 9 can be improved. The generation of problems due to the gaps between the end surfaces of the core feet 9 is suppressed by rubbing.

JP 2002-25827 A JP-A-5-47567

  However, although the gap between the tip surfaces of the core feet 9 can be reduced by rubbing the cores, the gap cannot be eliminated. It is said that the coil inductance value is reduced due to the core gap in the road), and that magnetic flux leaks from the gap between the tip surfaces of the core feet 9 and causes noise in the signals of the surrounding circuits. A problem will occur.

  Also, since the core members 4a and 4b are divided, as described above, in order to attach the core members 4a and 4b to the circuit board 2, the core member 4a is disposed on the surface side of the circuit board 2, and the circuit board The core member 4b is arranged on the back surface side of 2 and the core members 4a and 4b are combined using the core foot insertion through hole 10, and then the combined state of the core members 4a and 4b is combined with the core combination member 5. It is very troublesome work to use and hold.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a transformer-integrated circuit board in which the core can be easily attached to the circuit board and the performance of the transformer can be improved. It is in.

  In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. That is, according to the present invention, the circuit board includes a transformer coil pattern for the primary coil and the secondary coil, a coil pattern for the tertiary coil respectively disposed on both sides of the transformer coil pattern, and the outside of the transformer coil pattern forming portion. A middle slit extending from the position across the coil pattern for the primary coil and the coil pattern for the secondary coil to the inner region surrounded by these coil patterns, and for the tertiary coil respectively arranged in parallel on both sides of the middle slit There is a lateral slit that extends across the coil pattern to the inner region surrounded by the coil pattern for the tertiary coil, and is arranged on the central magnetic path leg and on both sides with a gap between each. The central magnetic path foot of the closed magnetic path core with the outer magnetic path legs In addition, the outer magnetic path legs on both sides of the central magnetic path leg of the closed magnetic path core are inserted into the lateral slits, respectively, and each magnetic path leg of the closed magnetic path core is positioned in the inner region surrounded by the corresponding coil pattern. The closed magnetic circuit core is disposed on the circuit board, and is electrically connected in such a manner that the coil pattern portions on both sides of the divided coil coil pattern and the secondary coil coil pattern divided by the middle slit are bridged. And a coil pattern conduction connecting means for conducting electricity in such a manner that the coil pattern portions on both sides of the divided part of the coil pattern for the tertiary coil divided by the lateral slit are surface-mounted on the circuit board. The coil pattern conduction connecting means is also used as a retaining means for the closed magnetic circuit core.

  According to this invention, since a closed magnetic path core is used, there is no gap (gap) between the core members in the magnetic path as seen when, for example, a pair of core members are combined to constitute the core of the coil, Thereby, it is possible to prevent occurrence of problems such as a decrease in the inductance value of the coil and leakage of magnetic flux due to the gap.

  Also, since a closed magnetic path core is used, there is no core gap in the magnetic path. For example, when a core of a coil is configured by combining a pair of core members (when there is a core gap in the magnetic path) In comparison, the magnetic resistance can be reduced. As a result, the core can be reduced in size, so that the entire transformer can be reduced in size, the area occupied by the transformer in the transformer-integrated circuit board can be reduced, and the mounting area of the components can be increased. be able to.

  Further, for example, when a core of a coil is configured by combining a pair of E-shaped core members, a core gap is generated in the magnetic path on both sides of the core. The gap between the core gap in the magnetic path on one side and the core gap in the magnetic path on the other side, for example, is different due to the magnetic material constituting the core. For this reason, there is a problem that the inductance value of the tertiary coil formed around the magnetic path on one side and the inductance value of the tertiary coil formed around the magnetic path on the other side are likely to vary. appear. On the other hand, in this invention, since the closed magnetic path core is used, there is no core gap in the magnetic path on both sides of the closed magnetic path core, so that the magnetic path on one side is formed around the center. The inductance value of the tertiary coil and the inductance value of the tertiary coil formed with the magnetic path on the other side as the center are substantially equal to each other, so that the balance can be maintained.

  Furthermore, since the closed magnetic path core is used, the troublesome assembly work of the core member is unnecessary.

  Furthermore, in this invention, since the closed magnetic circuit core is used, in order to attach the closed magnetic circuit core to the circuit board, a slit that crosses the transformer coil pattern and the coil pattern for the tertiary coil is formed on the circuit board. Has been. The coil pattern portions on both sides of the divided portion of the coil pattern divided by the slits are connected by coil pattern conduction connecting means provided in a manner that bridges the coil pattern portions on both sides. In this invention, the coil pattern conduction connecting means is configured to be surface-mounted on the circuit board, and the coil pattern conduction connecting means is also surface-mounted on the circuit board at the same time in the process of surface mounting other components on the circuit board. Therefore, the coil pattern conduction connecting means can be fixed to the circuit board very easily and without increasing the number of manufacturing steps.

  Further, by surface-mounting the coil pattern conduction connecting means on the circuit board, it is possible to suppress an increase in resistance value and an increase in power loss at a connection portion between the coil pattern conduction connecting means and the coil pattern. Furthermore, since the coil pattern conduction connecting means and the circuit board can be firmly bonded by surface-mounting the coil pattern conduction connecting means on the circuit board, the reliability of the connection between the coil pattern conduction connecting means and the circuit board is improved. Can be improved. Furthermore, it is possible to produce an effect that the area occupied by the joint portion required for joining the coil pattern conduction connecting means to the circuit board can be kept small.

  Further, since the coil pattern conduction connecting means is also used as a retaining means for the closed magnetic circuit core, it is possible to prevent the problem that the closed magnetic circuit core is detached from the circuit board without providing a dedicated part for retaining the coil pattern. Can do.

  Furthermore, by providing a structure in which the core locking portion is provided in the slit, the closed magnetic path core is brought into a predetermined set position only by locking the magnetic path foot of the closed magnetic path core to the core locking portion of the slit. It can be positioned and arranged easily.

  Even if the circuit board is constituted by a multilayer board, a coil pattern is formed on the inner layer of the circuit board, and the coil pattern of the inner layer is divided by a slit, a through hole formed in the circuit board, By utilizing the coil pattern conduction connecting means, the coil pattern portions on both sides of the divided portion of the inner layer coil pattern can be conducted.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 (a) shows a typical component part of the transformer-integrated circuit board of this embodiment in a schematic perspective view, and FIG. 1 (b) schematically shows an exploded view of that part. Further, FIG. 2 shows a schematic exploded view of only the circuit board portion shown in FIGS. 1 (a) and 1 (b).

The transformer integrated circuit board 20 of this embodiment is configured by a multilayer board in which a plurality of insulating boards 21 a and 21 b are stacked with an insulating layer 22 interposed therebetween. The transformer-integrated circuit board 20 is formed with a transformer coil pattern 23 as described below, transformer coil patterns 24 and 25, a middle slit 26, and side slits 27 and 28. The closed magnetic circuit core 29 and coil pattern conduction connecting means 30 (30a, 30b), 31 (31a, 31b), 32 (32a, 32b) are mounted, and the circuit board 20 has the equivalent of FIG. A transformer T having a primary coil N1, a secondary coil N2, and tertiary coils N3 ₁ and N3 ₂ as shown in the circuit diagram is integrally provided.

  The transformer coil pattern 23 includes a coil pattern 33 for a primary coil and a coil pattern 34 for a secondary coil. In the example shown in FIG. 2, the coil pattern 33 for the primary coil includes conductor patterns 33a, 33b, 33c, 33d, and 33e formed on the surface side of the insulating substrate 21a of the circuit board 20, and the back surface side of the insulating substrate 21a. The conductor patterns 33f and 33g are formed. The through hole 35a formed in the insulating substrate 21a electrically connects one end side of the conductor pattern 33c on the front surface side and the conductor pattern 33f on the back surface side of the insulating substrate 21a, and the through hole formed in the insulating substrate 21a. The other end side of the conductor pattern 33e on the front surface side and the conductor pattern 33f on the back surface side of the insulating substrate 21a is electrically connected by the hole 35b, and further, the through hole 35c formed in the insulating substrate 21a allows the insulating substrate 21a to The conductor pattern 33d on the front surface side and the conductor pattern 33g on the back surface side are electrically connected.

  The coil pattern 34 for the secondary coil includes conductor patterns 34a and 34b formed on the front surface side of the insulating substrate 21b of the circuit board 20, and conductor patterns 34c, 34d, 34e, 34f, and 34g formed on the back surface of the insulating substrate 21b. And is configured. Through the through hole 36a formed in the insulating substrate 21b, the conductor pattern 34a on the front surface side and the conductor pattern 34f on the back surface side of the insulating substrate 21b are electrically connected, and the through hole 36b formed in the insulating substrate 21b. Thus, one end side of the conductor pattern 34b on the front surface side of the insulating substrate 21b and the conductor pattern 34g on the back surface side are electrically connected, and further, the conductor on the front surface side of the insulating substrate 21b is formed by a through hole 36c formed in the insulating substrate 21b. The conductor pattern 34c on the other end side and the back surface side of the pattern 34b is electrically connected.

  Further, the coil pattern 24 for the tertiary coil is arranged on the left side of the transformer coil pattern 23 in the example shown in FIG. 2, and the coil pattern 24 for the tertiary coil is a conductor formed on the surface side of the insulating substrate 21a. It has patterns 24a and 24b and coil patterns 24c and 24d formed on the back side of the insulating substrate 21b. The conductor pattern 24b formed on the front surface side of the insulating substrate 21a and the conductor pattern 24c formed on the back surface side of the insulating substrate 21b are the back surface of the insulating substrate 21b through the insulating layer 22 from the front surface side of the insulating substrate 21a. It is electrically connected by a through hole 37 reaching the side.

  In the example of FIG. 2, the coil pattern 25 for the tertiary coil is disposed on the right side of the transformer coil pattern 23 and has the same configuration as the coil pattern 24 for the tertiary coil. That is, the coil pattern 25 for the tertiary coil includes the conductor patterns 25a and 25b formed on the front surface side of the insulating substrate 21a and the coil patterns 25c and 25d formed on the back surface side of the insulating substrate 21b. Has been. The conductor pattern 25b formed on the front surface side of the insulating substrate 21a and the conductor pattern 25c formed on the back surface side of the insulating substrate 21b are the back surface of the insulating substrate 21b through the insulating layer 22 from the front surface side of the insulating substrate 21a. It is electrically connected by a through hole 38 extending to the side.

  The middle slit 26 extends from the outer position of the formation part of the transformer coil pattern 23 (in this embodiment, the edge of the circuit board 20) to the inner region surrounded by the transformer coil pattern 23 across the transformer coil pattern 23. Elongated. Further, the lateral slit 27 is juxtaposed to the left of the middle slit 26, and the lateral slit 27 is positioned outside the formation portion of the coil pattern 24 for the tertiary coil (in this embodiment, the circuit board 20). From the end edge) to the inner region surrounded by the coil pattern 24 for the third coil across the coil pattern 24 for the third coil. Further, the lateral slit 28 is juxtaposed on the right side of the middle slit 26, and the lateral slit 28 is located outside the formation part of the coil pattern 25 for the tertiary coil (this implementation) like the lateral slit 27. In the embodiment, it extends from the edge of the circuit board 20 to the internal region surrounded by the coil pattern 25 for the tertiary coil across the coil pattern 25 for the tertiary coil.

  The closed magnetic path core 29 includes a central magnetic path leg 40 and outer magnetic path legs 41a and 41b arranged on both sides with a gap therebetween. In this embodiment, the slit width d1 of the middle slit 26 is slightly larger than the width D1 of the central magnetic path leg 40 of the closed magnetic path core 29, and the slit widths d2, d3 is slightly wider than the widths D2 and D3 of the outer magnetic path legs 41a and 41b of the closed magnetic path core 29.

  The closed magnetic path core 29 has the central magnetic path leg 40 inserted into the middle slit 26, the outer magnetic path leg 41a inserted into the lateral slit 27, and the outer magnetic path leg 41b inserted into the lateral slit 28, respectively. The central magnetic path leg 40 is attached to the circuit board 20 in such a manner that the central magnetic path leg 40 is arranged at the center of the transformer coil pattern 23 and the outer magnetic path legs 41a and 41b are arranged at the central parts of the coil patterns 24 and 25 for the tertiary coil. It is done. In this embodiment, a protruding portion K that protrudes to the left as shown in FIG. 1 (b) is formed on the extending tip side of the middle slit 26 and the lateral slits 27 and 28, respectively. The overhanging portion K of the middle slit 26 has such a size that a part of the central magnetic path leg 40 of the closed magnetic path core 29 is fitted, and the overhanging portion K of the lateral slits 27 and 28 is the outer magnetic field of the closed magnetic path core 29. The road legs 41a and 41b have a size that allows a part of the road legs 41a and 41b to be fitted, the side surface of the central magnetic path leg 40 is locked to the side wall surface of the protruding portion K of the middle slit 26, and the side slits 27 and 28 are engaged. By positioning the side surfaces of the outer magnetic path legs 41a and 41b on the side wall surface of the overhang portion K, the position of the closed magnetic path core 29 can be positioned. That is, each overhanging portion K of the middle slit 26 and the side slits 27 and 28 is a core locking portion.

  The coil pattern conduction connecting means 30, 31 and 32 are provided on both sides of the divided portions of the transformer coil pattern 23 (33, 34) and the tertiary coil coil patterns 24 and 25 divided by the middle slit 26 and the side slits 27 and 28, respectively. The coil pattern portion is made to conduct in a manner of being bridged, and the coil pattern conduction connecting means 30, 31, 32 are surface-mounted on the circuit board 20. In this embodiment, the coil pattern conduction connecting means 30, 31, 32 include a board piece 43 as shown in the model diagram of FIG. 4 and one or more conductor patterns 44 formed on the board piece 43. It has the form which has.

  That is, three conductor patterns 44 are formed in the coil pattern conduction connecting means 30a, and one of the three conductor patterns 44 is included in the conductor patterns 33a and 33b of the coil pattern 33 for the primary coil. The ends facing each other through the slit 26 are electrically connected to each other, and another conductor pattern 44 is electrically connected to the conductor patterns 33d and 33e, and another conductor pattern 44 is a conductor pattern. 33c and 33b are electrically connected. In addition, three conductor patterns 44 are also formed in the coil pattern conduction connecting means 30b, and one of the three conductor patterns 44 is the conductor pattern 34d, 34e of the secondary coil coil pattern 34. The ends facing each other through the middle slit 26 are electrically connected, another conductor pattern 44 is electrically connected to the conductor patterns 34f and 34g, and another conductor pattern 44 is further connected to the conductor patterns 34c, 34c, 34d is electrically connected.

  One conductive pattern 44 is formed in the coil pattern conduction connecting means 31a, and this conductive pattern 44 is an end portion facing each other through the lateral slits 27 of the conductive patterns 24a and 24b of the coil pattern 24 for the tertiary coil. They are electrically connected to each other. Similarly, a single conductor pattern 44 is also formed on the coil pattern conduction connecting means 31b. The conductor pattern 44 is opposed to the conductor patterns 24c and 24d of the coil pattern 24 for the tertiary coil via the lateral slits 27. The end portions that meet each other are electrically connected to each other.

  One conductive pattern 44 is formed in the coil pattern conduction connecting means 32a, and this conductive pattern 44 is an end portion facing each other through the lateral slits 28 of the conductive patterns 25a and 25b of the coil pattern 25 for the tertiary coil. They are electrically connected to each other. Similarly, a single conductor pattern 44 is also formed on the coil pattern conduction connecting means 32b, and this conductor pattern 44 is opposed to the conductor pattern 25c, 25d of the coil pattern 25 for the tertiary coil via the lateral slit 28. The end portions that meet each other are electrically connected to each other.

  In this embodiment, the primary coil N1 of the transformer T includes a primary coil coil pattern 33 (conductor patterns 33a to 33g), through holes 35 (35a to 35c), and coil pattern conduction connection means 30a. It is configured. For example, the energization current of the primary coil N1 is as follows: the conductor pattern 33a → the conductor pattern 44 of the coil pattern conduction connecting means 30a → the conductor pattern 33b → the conductor pattern 44 of the coil pattern conduction connecting means 30a → the conductor pattern 33c → the through hole 35a → the conductor pattern. The primary coil N1 is energized through a path 33f → through hole 35b → conductor pattern 33e → conductor pattern 44 of the coil pattern conduction connecting means 30a → conductor pattern 33d → through hole 35c → conductor pattern 33g.

  The secondary coil N2 of the transformer T includes a secondary coil coil pattern 34 (conductor patterns 34a to 34g), through holes 36a to 36c, and coil pattern conduction connecting means 30b. For example, the energizing current of the secondary coil N2 is as follows: conductor pattern 34e → conductor pattern 44 of coil pattern conduction connecting means 30b → conductor pattern 34d → conductor pattern 44 of coil pattern conduction connecting means 30b → conductor pattern 34c → through hole 36c → conductor The secondary coil N2 is energized along the path of pattern 34b → through hole 36b → conductor pattern 34g → conductor pattern 44 of coil pattern conduction connecting means 30b → conductor pattern 34f → through hole 36a → conductor pattern 34a.

The tertiary coil N3 ₁ of the transformer T includes, for example, a coil pattern 24 (conductor patterns 24a to 24d) for a tertiary coil, a through hole 37, and coil pattern conduction connecting means 31 (31a, 31b). . For example, the energizing current of the tertiary coil N3 ₁ is as follows: conductor pattern 24a → conductor pattern 44 of coil pattern conduction connecting means 31a → conductor pattern 24b → through hole 37 → conductor pattern 24c → conductor pattern 44 of coil pattern conduction connecting means 31b → conductor The tertiary coil N3 ₁ is energized along the path of the pattern 24d.

The tertiary coil N3 ₂ of the transformer T includes, for example, a coil pattern 25 for the third coil (conductor patterns 25a to 25d), a through hole 38, and coil pattern conduction connection means 32 (32a, 32b). . For example, the energizing current of the tertiary coil N3 ₂ is as follows: conductor pattern 25a → conductor pattern 44 of coil pattern conduction connecting means 32a → conductor pattern 25b → through hole 38 → conductor pattern 25c → conductor pattern 44 of coil pattern conduction connecting means 32b → conductor The tertiary coil N3 ₂ is energized along the path of the pattern 25d.

The transformer T integrally provided on the circuit board 20 shown in this embodiment can be incorporated into various circuits. For example, the transformer T is an insulating switching type. It can be incorporated into a power supply circuit. For example, when the tertiary coil N3 ₁ is connected to the synchronous rectifier 46 as shown by the dotted line in FIG. 3 of the switching power supply circuit as drive control means, and the tertiary coil N3 ₂ is connected to the synchronous rectifier 47 as drive control means. The synchronous rectifier 47 is switched off when the synchronous rectifier 46 is switched on by the voltage generated in the tertiary coils N3 ₁ and N3 _2. On the contrary, when the synchronous rectifier 46 is switched off, the synchronous rectifier 47 is switched off. The switch is turned on, and the switching on / off timing of the synchronous rectifiers 46 and 47 is synchronized with the switching operation of the switch element Q connected to the primary coil N1.

In this embodiment, since the closed magnetic path core 29 is used, there is no gap in the outer magnetic path legs 41a and 41b of the closed magnetic path core 29, and the outer magnetic path legs 41a and 41b are the tertiary coils N3 ₁ and N3. Since it is disposed in the inner region of the _second coil patterns 24 and 25, variation in the inductance value of the tertiary coil N3 _{1 and} the inductance value of the tertiary coil N3 ₂ due to the gap of the core can be avoided. The inductance values of the tertiary coils N3 ₁ and N3 ₂ can be made the same. For this reason, since the change of the voltage generated in the tertiary coils N3 ₁ and N3 ₂ can be synchronized with high accuracy, the timing of the on / off operation of the synchronous rectifiers 46 and 47 can be adjusted with high accuracy.

  In this embodiment example, as shown in FIG. 1, the coil pattern conduction connecting means 30, 31, 32 are arranged in a manner extending over both sides of the middle slit 26 and the lateral slits 27, 28. The coil pattern conduction connecting means 30, 31, 32 can prevent the closed magnetic circuit core 29 from being detached from the circuit board 20. That is, the coil pattern conduction connecting means 30, 31, 32 are also used as means for preventing the closed magnetic circuit core 29 from coming off.

  In this embodiment, the closed magnetic path core 29 that is prevented from coming off by the coil pattern conduction connecting means 30, 31, 32 and positioned by the core locking portion K of the slits 26 to 28 is made of a thermosetting resin or the like. It is fixed to the circuit board 20 with an adhesive material. By using a thermosetting resin as an adhesive material for fixing the closed magnetic circuit core 29 to the circuit board 20, the thermosetting resin is simultaneously melted when the components are surface-mounted on the circuit board 20 in the reflow process, thereby closing the closed magnetic circuit. The core 29 can be bonded and fixed to the circuit board 20.

  In addition, this invention is not limited to the form of this embodiment, Various embodiment can be taken. For example, in this embodiment, the coil pattern conduction connecting means 30 to 32 have a form in which the conductor pattern 44 is formed on the substrate piece 43, but the coil pattern conduction connecting means is divided by a slit. The form is not particularly limited as long as the coil pattern portions on both sides of the divided part of the coil pattern can be electrically connected. For example, the zero Ω resistance component 48 as shown in FIG. Or the form like the jumper metal fitting 49 as shown in FIG.5 (b) may be sufficient. Even when the coil pattern conduction connecting means is constituted by the zero Ω resistance component 48 and the jumper fitting 49, the coil pattern conduction connection means (the zero Ω resistance component 48 and the jumper fitting 49) is surface-mounted on the circuit board 20. .

  When the jumper fitting 49 is used, the jumper fitting 49 can be applied to the closed magnetic circuit core 29 from the jumper fitting 49 when the jumper fitting 49 is surface-mounted on the set position of the circuit board 20. It is good also as a structure which gives elasticity to. With such a configuration, the closed magnetic path core 29 can be fixed with an elastic force by the jumper fitting 49.

  In this embodiment, the middle slit 26 and the lateral slits 27 and 28 are formed to extend from the edge of the circuit board 20, respectively. For example, the middle slit 26 and the lateral slits 27 and 28 are For example, as shown in FIGS. 6A and 6B, a distance from the edge of the circuit board 20 is formed. You may form in the position interposed. In the case of the configuration shown in FIGS. 6A and 6B, the central magnetic path leg 40 and the outer magnetic path legs 41a and 41b of the closed magnetic path core 29 are provided in the middle slit 26 and the lateral slits 27 and 28, respectively. For insertion, a core dropping hole 50 is formed in which the closed magnetic path core 29 is dropped and arranged on the circuit board 20.

  Furthermore, in this embodiment, the core locking portion K is provided in all of the middle slit 26 and the lateral slits 27, 28. For example, the core locking portion K is provided only in the lateral slits 27, 28. It is good also as a structure by which the core latching | locking part K is provided only in the inside slit 26. For example, when the core locking portion K having the form shown in FIG. 1 is provided only in the middle slit 26, the lateral slits 27 and 28 on which the core locking portion K is not provided are provided on the middle slit 26. The slit width is formed so as to be wider than the width of the outer magnetic path leg of the closed magnetic path core 29 in accordance with the protruding portion of the core locking portion K. The same applies to the case where the core locking portion K having the form shown in FIG. 1 is provided only in the lateral slits 27 and 28, and the middle slit 26 in which the core locking portion K is not provided is the lateral slit 27. , 28 is formed so that the slit width is wider than the width of the central magnetic path leg of the closed magnetic path core 29 in accordance with the overhang of the core locking portion K of the closed magnetic path core 29. Moreover, it is good also as a structure by which the core latching | locking part K is not provided in all of the inside slit 26 and the side slits 27 and 28.

  Further, in this embodiment, the coil patterns 24 and 25 for the tertiary coil are formed on both sides of the transformer coil pattern 23. However, depending on the circuit configuration in which the transformer T is incorporated, It is good also as a structure in which only one side is formed. Thus, when only one side of the coil patterns 24, 25 for the tertiary coil is formed, one of the coil pattern conduction connection means 31, 32 is selected according to the coil pattern for the tertiary coil on the omitted side. The side may be omitted.

  Furthermore, in this embodiment, the circuit board 20 is a multilayer board. However, for example, the circuit board 20 may be a single-layer board that is not a multilayer board. In this case, naturally, the coil pattern 33 for the primary coil and the coil pattern 34 for the secondary coil in the transformer coil pattern 23 have a shape for a single-layer circuit board.

  Furthermore, the form of the closed magnetic path core 29 is not limited to the form shown in FIG. 1. For example, the central magnetic path legs 40 and the outer magnetic path legs 41 a and 41 b of the closed magnetic path core 29 are cylindrical. As described above, the closed magnetic path core 29 may have other forms. Of course, the pattern shapes of the coil pattern 33 for the primary coil, the coil pattern 34 for the secondary coil, and the coil patterns 24 and 25 for the tertiary coil are also limited to the example illustrated in FIG. is not.

It is a figure for demonstrating the example of one Embodiment of a transformer integrated circuit board. FIG. 2 is a schematic exploded view of components unique to the embodiment of the transformer-integrated circuit board shown in FIG. 1. It is an equivalent circuit diagram of the transformer provided on the transformer integrated circuit board of the embodiment. It is a model figure which shows one example of a coil pattern conduction | electrical_connection connection means. It is a model figure showing the other example of a coil pattern conduction | electrical_connection connection means. It is a model figure showing the other example of a form of a slit. It is a figure for demonstrating one example of the coil apparatus provided integrally with the circuit board.

Explanation of symbols

20 Transformer integrated circuit board 23 Transformer coil pattern 24, 25 Coil pattern for tertiary coil 26 Middle slit 27, 28 Side slit 29 Closed magnetic circuit core 30, 31, 32 Coil pattern conduction connecting means 33 Coil pattern for primary coil 34 Secondary Coil pattern for coil 40 Central magnetic path foot 41a, 41b Outer magnetic path foot

Claims (4)

  The circuit board includes a transformer coil pattern for the primary coil and the secondary coil, a coil pattern for the tertiary coil respectively disposed on both sides of the transformer coil pattern, and a coil for the primary coil from the outer position of the transformer coil pattern forming portion. A middle slit that extends across the pattern and the coil pattern for the secondary coil to the inner region surrounded by the coil pattern, and a coil that is arranged in parallel on both sides of the middle slit and across the coil pattern for the tertiary coil A lateral slit extending to the inner region surrounded by the coil pattern for the tertiary coil is provided, and a central magnetic path leg and outer magnetic path legs respectively disposed on both sides with a gap therebetween The central magnetic path foot of the closed magnetic circuit core with the middle slit, and the center of the closed magnetic circuit core The outer magnetic path legs on both sides of the path legs are respectively inserted into the lateral slits, and the closed magnetic path cores are positioned on the inner regions surrounded by the corresponding coil patterns. A coil pattern conduction connecting means for conducting in a manner of bridging the coil pattern portions on both sides of each divided portion of the coil pattern for the primary coil and the coil pattern for the secondary coil divided by the middle slit. The coil pattern conduction connecting means for conducting the coil pattern portions on both sides of the divided part of the coil pattern for the tertiary coil divided by the side slit is surface-mounted on the circuit board, and the coil pattern conduction connecting means Is a circuit board integrated with a transformer, which is also used as a retaining means for the closed magnetic circuit core.   At least one of the middle slit and the lateral slit is provided with a core locking portion for locking and closing the closed magnetic path core by locking the magnetic path foot of the closed magnetic path core. The transformer-integrated circuit board according to claim 1.   The circuit board is a multilayer board formed by laminating a plurality of boards, and the coil pattern on at least one of the coil pattern for the primary coil and the coil pattern for the secondary coil is formed on the circuit board in the transformer coil pattern forming portion. The coil pattern portions on both sides of the split portion of the inner layer coil pattern divided by the middle slit are through holes extending from the respective coil pattern portions on both sides to the circuit board surface, and these through holes. 3. The transformer-integrated circuit board according to claim 1, wherein the transformer integrated circuit board is electrically connected using a coil pattern conduction connecting means for electrically connecting the two.   3. The coil pattern for the tertiary coil is provided only on one side of the transformer coil pattern, instead of forming the coil pattern for the tertiary coil on both sides of the transformer coil pattern, respectively. Alternatively, the transformer-integrated circuit board according to claim 3.

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