JP2009193977A - Integrated device, and llc resonant converter mounting it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an integrated device which integrates other passive elements together with a transformer, and to provide an LLC resonant converter with the integrated device. <P>SOLUTION: On the premise that passive elements are integrated, an integrated device comprises a first flexible substrate (30) wound around a magnetic core (10) and having a copper layer on the surface, a second flexible substrate (20) wound around the magnetic core (10) to surround the most outer circumferential surface of the first flexible substrate (30) and having a copper layer on the surface, and a layer (40) of a magnetic material interposed between the first flexible substrate (30) and the second flexible substrate (20). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an integrated device that integrates passive elements, and more particularly, to an integrated device that integrates other passive elements together with a transformer, and an LLC resonant converter constituted by the integrated device.

  In recent years, the trend toward development of “light, thin, and small” in consumer electronic products has been demanding higher power density for electronic power converters. In order to achieve high power density, the key is how to reduce the volume of the passive element. This is because the passive elements in the electronic power converter account for most of the total volume. Higher frequency is one important direction for reducing the volume of passive elements.

Another direction is the integration of passive elements. For this, a small inductor-capacitor processor made of metal foil is disclosed to realize integration of inductors and capacitors (see Patent Documents 1 to 3).
Chinese patent ZL02801543.6 International Application Publication WO02 / 093593 Special table 2004-529574

Electronic power converters, especially electronic power converters applied in consumer electronic products, usually need to be insulated with a transformer from the viewpoint of safety.
If integration of transformers, inductors, and capacitors can be realized in the power converter, a wider range of passive elements can be integrated, which is more meaningful. However, until now, no other passive element has been integrated with the transformer. Therefore, there has been a problem that integration in the power conversion device does not progress.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an integrated device that integrates other passive elements together with a transformer, and an LLC resonant converter equipped with the integrated device.

In order to solve the above problems, the present invention is configured as follows.
One aspect of the integrated device of the present invention is to integrate passive elements, and includes a first flexible substrate wound around a magnetic core and having a copper layer on the surface, and the first flexible substrate. A second flexible substrate having a copper layer on the surface wound around the magnetic core so as to surround the outermost peripheral surface, and the magnetic material interposed between the first flexible substrate and the second flexible substrate. And a layer of material.

The first flexible substrate may be configured to have two or more copper layers insulated from each other.
Moreover, it is preferable that the said magnetic core is provided in the passage path of the magnetic flux which crosses perpendicularly to the winding surface of said 1st flexible substrate and a 2nd flexible substrate.

Moreover, it is preferable to have an air gap for adjusting an exciting inductance value in a part of the magnetic core.
The magnetic core may be composed of a combination of a first magnetic core having an E shape and a second magnetic core having an E shape, and a first magnetic core having a U shape and a U shape. It may be comprised with the coupling body of the 2nd magnetic core which makes | forms. In the former case, the first flexible substrate and the second flexible substrate are wound around the central magnetic core column among the three magnetic core columns, and in the latter case, the first flexible substrate and the second flexible substrate are wound around one of the magnetic core columns. Be dressed.

  Moreover, it is preferable that a polyimide film is used for the first flexible substrate and / or the second flexible substrate, and the magnetic material interposed between the first flexible substrate and the second flexible substrate is used. Ferrite polymers may be used.

  In the integrated device of the present invention, the first flexible substrate, the second flexible substrate, and the magnetic core constitute a transformer. And since there is a magnetic material layer between the first flexible substrate and the second flexible substrate, the first flexible substrate operates as a coil to constitute an inductor. The first flexible substrate constitutes a capacitor when the copper layer includes two or more copper layers insulated from each other.

One aspect of the LLC resonant converter of the present invention is configured to mount the integrated device according to any one of the above-described integrated devices.
In the LLC resonant converter of the present invention, each copper layer of the first flexible board and the second flexible board is connected to a circuit through bonding pads or the like, so that the transformer and passive elements in the LLC resonant converter are connected. Can be integrated. In particular, when the first flexible substrate is a first flexible substrate having two or more copper layers insulated from each other, each of the copper layers is connected to a circuit through a bonding pad or the like. Thus, a resonant capacitor or a resonant inductor can be integrated as a passive element together with the transformer in the LLC resonant converter.

  The present invention makes it possible to integrate other passive elements with the transformer. Moreover, since the passive element of the LLC resonant converter can be integrated in the transformer, the output density per physique increases.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
As the best mode for carrying out the present invention, a passive element integration method and a configuration of an integrated device in an LLC resonant converter will be described here.

  The integrated device is configured using a flexible substrate such as a double-sided flexible substrate and a single-sided flexible substrate described later. This "flexible board" is a Japanese translation of "Flexible Printed Circuit" and is classified as a type of printed circuit board formed by metal wiring on an insulating plate. A particularly characteristic point of the flexible substrate is that it is so flexible that it can be bent and wound, such as a thin and flexible polyimide film used for a substrate of an amorphous solar cell film. That is, it is used instead of the insulating plate. Hereinafter, a polyimide film or the like used in place of the insulating plate is simply referred to as a “flexible substrate” to be distinguished from the insulating plate. In addition, the entire structure constituted by a flexible substrate is also referred to as a “flexible substrate” as appropriate. Various metal wiring patterns for realizing electrical connection can be manufactured on the flexible substrate. However, in the application of the inventors, a copper layer is laid on both sides or the entire surface. A copper pad is provided with a bonding pad for connection to an external circuit.

  The double-sided flexible substrate is a flexible substrate having a structure having a copper layer on the surface. If two or more copper layers insulated from each other are provided on the surface of the flexible substrate as the copper layer, a polyimide film or the like interposed between the two copper layers acts as an insulating medium. Therefore, a resonant capacitor in the LLC resonant converter is configured by providing bonding pads on each copper layer and connecting them to an external circuit of the LLC resonant converter (such as a circuit composed of electronic components that are not integrated).

  Further, by winding the double-sided flexible substrate around the magnetic core, the copper layer portion becomes a primary winding of a transformer described later, and a parallel-connected inductor (excitation inductor) in the LLC resonant converter is configured.

  The single-sided flexible substrate is a flexible substrate having a structure having one copper layer on the surface. The single-sided flexible board is wound around the magnetic core so as to surround the outermost peripheral surface of the double-sided flexible board, and further, bonding pads are provided at both ends of the single-sided flexible board to connect to the external circuit of the LLC resonant converter. By doing so, the copper layer portion on the surface of the single-sided flexible substrate becomes a secondary winding for the primary winding, and a transformer in the LLC resonant converter is configured.

  The magnetic core is made of a magnetic material that easily allows the magnetic flux generated around the copper layers to pass therethrough, and provides a magnetic path having a lower resistance than air. Here, the primary winding and the secondary winding are combined to form the transformer. If an air gap is provided in the magnetic core, the size of the exciting inductor can be adjusted.

  If a magnetic material layer is further arranged between the double-sided flexible substrate and the single-sided flexible substrate, the leakage inductance in the transformer is increased and can be used as a series-connected inductor (resonant inductor) in the LLC resonant converter. . The size of the resonant inductor can be adjusted by changing the thickness of the magnetic material layer, the length in the height direction, the number of turns, and the like.

The manufacturing of the integrated device includes a step of manufacturing a double-sided flexible substrate and a single-sided flexible substrate, a step of winding and fixing a double-sided flexible substrate and a single-sided flexible substrate around a magnetic core, and a magnetic material layer as necessary, The step of connecting the copper layer of the flexible substrate and the copper layer of the single-sided flexible substrate to an external circuit through bonding pads is performed.
(Example 1)
FIG. 1 is a structural diagram of the integrated device according to the first embodiment. 1A shows the overall structure of the integrated device, and FIG. 1B shows the structure of the portion corresponding to the lower half of the magnetic core.

  In the integrated device 1 shown in FIG. 1A, an EE-shaped magnetic core 10 made of a ferromagnetic material is used as the magnetic core. The magnetic core 10 is a combination of a first magnetic core (“upper core 10-1”) and a second magnetic core (“lower core 10-2”), both of which have an E shape and are made of a ferromagnetic material. It is comprised, and it couple | bonds by the arrangement | positioning in which a through-hole is formed in the left-right position symmetrically. By coupling in this way, in the magnetic core 10 of FIG. 1 (A), three magnetic core pillars extending in the vertical direction, that is, the central pillar 10-5, the side pillar 10-6R, and the side Forming the column 10-6L, and between the center column 10-5 and the side column 10-6R and between the center column 10-5 and the side column 10-6L, respectively; An opening 10-7R and an opening 10-7L are formed as the through hole.

  And here, as a first flexible substrate having a copper layer on its surface, a double-sided flexible substrate 30 having two copper layers insulated from each other (also referred to as a first copper layer and a second copper layer), As a second flexible substrate having a copper layer on the surface, a single-sided flexible substrate 20 having a copper layer on the entire surface, with a magnetic material layer 40 such as a ferrite polymer (Ferrite Polymer Composite) interposed between the substrates. The single-sided flexible substrate 20 is wound around the central column 10-5 through the opening 10-7R and the opening 10-7L so as to surround the outermost peripheral surface of the double-sided flexible substrate 30.

  As apparent from FIG. 1 (B), the double-sided flexible board 30 is wound twice around the central column 10-5 with one side facing the outer peripheral surface of the central column 10-5. Provided. The single-sided flexible substrate 20 is provided so that one side is along the outermost peripheral surface of the double-sided flexible substrate 30 and is wound once around the central column 10-5, that is, surrounding the outermost peripheral surface. The magnetic material layer 40 is provided around the central column 10-5 between the outermost peripheral surface of the double-sided flexible substrate 30 and the innermost peripheral surface of the single-sided flexible substrate 20.

  It is desirable that the magnetic core 10 and the various flexible substrates 20 and 30 and the magnetic material layer 40 are firmly fixed with an adhesive tape or the like so as to withstand vibrations or not change physical properties.

FIG. 2 is a structural diagram in the thickness direction of the double-sided flexible substrate 30 when viewed from the upper side of FIG.
As shown in FIG. 2, the double-sided flexible board 30 includes a copper layer 300U and a copper layer 300D that are parallel to each other indicated by blank rectangular frames and an interlayer (between 300U and 300D) indicated by hatching in the thickness direction. Insulating layer 302 and the exposed surfaces of copper layer 300U and copper layer 300D, which are also indicated by hatched portions (in the figure, the upper boundary line of copper layer 300U and the lower boundary line of copper layer 300D are It has a structure composed of an insulating material 304U and an insulating material 304D that cover (shown as part of each exposed surface). This structure is configured by, for example, laying copper foil and an insulating material in order on both sides of a flexible substrate made of polyimide or the like, that is, on the front side surface and the back side surface orthogonal to the thickness direction. Is done.

Thus, here, as the double-sided flexible board 30, one provided with two copper layers insulated from each other on both sides is used.
The thickness of the flexible substrate can be realized with various thicknesses by the current manufacturing technology, but considering the flexibility as the design requirements of the inventors, the thickness of the flexible substrate is as thin as, for example, 1 mm order. Things are good.

  FIG. 3 shows a state in which the double-sided flexible board 30 of FIG. 1 (B) is viewed from above in FIG. 1 (B). In the drawing, both end portions of each of the copper layers 300U and 300D are indicated by an end portion 38, an end portion 36, an end portion 37, and an end portion 35. The connection between the double-sided flexible substrate 30 and an external circuit (not shown) of the LLC resonant converter is performed by connecting one end 38 of the one-side copper layer 300U and one end of the other-side copper layer 300D as shown in FIG. For example, bonding pads (not shown) are connected to 35 and bonding wires (not shown) are connected.

FIG. 4 is a structural diagram in the thickness direction of the single-sided flexible board 20 when viewed from the upper side of FIG.
As shown in FIG. 4, the single-sided flexible substrate 20 includes a copper layer 200 indicated by a blank rectangular frame and an exposed surface of the copper layer 200 indicated by a hatched portion (in FIG. 4, the upper boundary line of the copper layer 200 in the figure). And a lower boundary line is shown as a part of each exposed surface), and has a structure composed of an insulating material 204U and an insulating material 204D.

This structure is configured, for example, by covering the entire surface of a flexible substrate made of polyimide or the like with a copper foil and laying insulating materials 204U and 204D on both sides from the top.
Thus, here, as the single-sided flexible substrate 20, the one having a single copper layer on the entire surface of the flexible substrate is used.

The thickness of the flexible substrate is preferably as thin as, for example, the order of 1 mm as in the case of the double-sided flexible substrate 30.
FIG. 5 shows a state in which the single-sided flexible board 20 of FIG. 1 (B) is viewed from above in FIG. 1 (B). In the figure, both end portions in the length direction of the copper layer 200 are indicated by an end portion 23 and an end portion 24. The connection between the single-sided flexible substrate 20 and an external circuit (not shown) of the LLC resonant converter is provided with bonding pads on one end 23 and the other end 24 of the copper layer 200 as shown in the figure as an example, This is done by connecting a bonding wire (not shown).

  The equivalent circuit of the lumped parameter when the end portion 35 and the end portion 38 of the double-sided flexible substrate 30 are connected to an external circuit is as follows. That is, as shown in FIG. 6, a capacitor (corresponding to a resonant capacitor 71 in the circuit diagram of FIG. 7 described later) and an inductor (corresponding to a resonant inductor 72 in the circuit diagram of FIG. 7 described later) are connected in series. Become a thing.

  FIG. 7 is a circuit diagram of an LLC resonant converter configured as one of power converters using the integrated device described above. Here, as an example, a half bridge is applied to the primary circuit of the converter, and full bridge rectification is applied to the secondary rectifier circuit. That is, in the figure, the power device 61 and its body diode 63 and the power device 62 and its body diode 64 form a half-bridge inverter circuit. The rectifier diodes 65-68 and the capacitor 69 form a full bridge inverter circuit. Note that the present invention can be implemented even if the half bridge applied to the primary circuit of the converter is changed to a full bridge or the like. In addition, it can be implemented even if full-bridge rectification applied to the secondary-side rectifier circuit is changed to full-wave rectification.

  In the present embodiment, each passive element shown in a broken line C in FIG. The passive element shown here includes a transformer composed of a primary winding 74 and a secondary winding 75 surrounded by a rectangular broken line 76, a resonant capacitor 71 and a resonant inductor 72 connected in series on the primary winding 74 side, and There is an exciting inductor 73 connected in parallel on the primary winding 74 side. 3 and 5 are connected to the external circuit (here, a broken line) with the corresponding relationship shown in FIG. 7 through the bonding pads and the like. By connecting to the terminal of the circuit shown outside the frame of C, it is integrated into the integrated device as follows.

The resonant capacitor 71 includes two copper layers 300U and 300D provided on the double-sided flexible substrate 30 and an insulating medium 302 between them.
The primary winding 74 of the transformer is formed by the copper layer portions 300U and 300D of the double-sided flexible board 30 wound around the magnetic core 10. The first copper layer, the second copper layer, the first magnetic core, and the second magnetic core in the double-sided flexible board constitute a parallel inductor 73 in the LLC resonant converter, and the first copper in the double-sided flexible board. The layer and the second copper layer simultaneously form the primary winding 74 of the transformer 76.

  The value of the exciting inductor 73 (exciting inductance value) is such that an air gap (gap) is provided in the central column body 10-5 and the side column bodies 10-6R and 10-6L of the magnetic core 10 and the size thereof is changed. To adjust. For example, the upper core 10-1 of the EE core 10 and the central column body 10-5 of the lower core 10-2 are selected to be shorter than the side column bodies 10-6R, 10-6L, or joined to each other, or the upper core 10 -1 and the lower core 10-2 are appropriately separated. The position where the air gap is provided may be anywhere as long as the sum of the distances of the air gaps on the passage path of the magnetic flux flowing in the magnetic core 10 is the same. Therefore, on the passage path of the magnetic flux flowing through the magnetic core 10, for example, only the central column 10-5 is divided into positions other than the central column 10-5, or various positions including the central column 10-5. An air gap may be provided.

  The secondary winding 75 of the transformer is formed by the copper layer portion 200 of the single-sided flexible board 20 wound around the magnetic core 10. In the present embodiment, the magnetic core 10 includes a primary winding 74 made of the double-sided flexible substrate 30 and a single-sided flexible substrate 20 that vertically intersect the coil surface (winding surface) of the double-sided flexible substrate 30 in FIG. The secondary winding 75 is provided in the magnetic flux passage path. For this reason, the primary winding 74 and the secondary winding 75 are coupled by the magnetic flux in the magnetic core 10, thereby forming a transformer.

The resonant inductor 72 is formed by disposing the magnetic material layer 40 between the double-sided flexible substrate 30 and the single-sided flexible substrate 20.
That is, the leakage inductance of the transformer formed by the double-sided flexible substrate, the single-sided flexible substrate, and the upper and lower magnetic cores becomes the resonant inductor 72 in the LLC resonant converter, and the LLC resonant converter is adjusted by adjusting the thickness of the magnetic material layer. The inductance of the resonance inductor 72 can be adjusted. The magnetic material layer 40 returns the magnetic flux as the primary winding from the double-sided flexible substrate 30 to the single-sided flexible substrate 20 as the secondary winding without intermingling, and the leakage inductance in the transformer increases. Thereby, the double-sided flexible substrate 30 operates as a coil, and an inductance of a level that can be used as an inductor can be obtained. The value of the resonance inductor 72 (resonance inductance value) is adjusted by changing the thickness of the magnetic material layer 40, the length in the height direction, the number of turns, and the like.

  In the figure, reference numerals 35 and 38 are external circuit connection pads welded to the tip of the first copper layer and the tail end of the second copper layer in the double-sided flexible board, respectively, and 23 and 24 are the single-sided flexible board, respectively. It is a pad for connecting an external circuit welded to both ends of the copper layer.

  In the present embodiment, the EE shape is shown as the magnetic core 10, but not limited to this shape, any suitable shape may be used. For example, shapes such as EI, EQ, ETD, PQ, RM, or POT can be used. Alternatively, as shown in FIG. 8, the magnetic core can be formed of a first magnetic core 60-1 and a second magnetic core 60-2 both having a U shape and having two magnetic core pillars, The double-sided flexible substrate 30, the magnetic material layer 40, and the single-sided flexible substrate 20 are wound around one of the magnetic core pillars. Here, the magnetic material layer 40 may be a ferrite polymer. For the configurations of the double-sided flexible substrate 30, the magnetic material layer 40, and the single-sided flexible substrate 20 and a method of winding them around one of the magnetic core pillars, refer to the example of the EE shape described above.

  Further, the relationship between the widths of the double-sided flexible substrate 30 and the single-sided flexible substrate 20 (the vertical width in FIG. 1A) and the heights of the openings 10-7R and 10-7L formed in the magnetic core 10 is as follows. It is only necessary that the width of each of the flexible substrates 20 and 30 be within the height of the openings 10-7R and 10-7L.

  In this embodiment, each flexible board 20 and 30 is directly wound around the central pillar 10-5 of the magnetic core 10, but it is wound around a frame in order to increase the convenience of winding. Anyway.

  In this embodiment, the number of turns of the primary side and secondary side windings, that is, the double-sided flexible board 30 and the single-sided flexible board 20 is set to 2 turns and 1 turn, respectively. Alternatively, the integrated device may be configured by appropriately selecting a plurality of turns and winding the double-sided flexible substrate 30 and the single-sided flexible substrate 20 on the same axis.

In the present embodiment, one set of primary winding and secondary winding is shown, but a plurality of sets may be used according to needs.
In the present embodiment, the magnetic material layer 40 is provided between the double-sided flexible substrate 30 and the single-sided flexible substrate 20 in order to increase the leakage inductance, but the mutual distance between the double-sided flexible substrate 30 and the single-sided flexible substrate 20 is separated. Thus, the leakage inductance may be increased.

  As described above, in the integrated device of this embodiment, the resonant inductor, the resonant capacitor, and the exciting inductor can be integrated in the transformer in the LLC resonant converter. Therefore, the output density per physique in the LLC resonant converter is increased.

1 is a structural diagram of an integrated device according to Embodiment 1. FIG. FIG. 2 is a structural diagram in the thickness direction of a double-sided flexible board 30 when viewed from the upper side of FIG. FIG. 1B shows the double-sided flexible board 30 as viewed from above in FIG. FIG. 2 is a structural diagram in the thickness direction of a single-sided flexible board 20 when viewed from the upper side of FIG. FIG. 1B shows the single-sided flexible substrate 20 as viewed from above in FIG. 3 is an equivalent circuit of a lumped parameter of the double-sided flexible substrate 30. FIG. 1 is a circuit diagram of an LLC resonant converter configured using an integrated device according to Embodiment 1. FIG. FIG. 5 is a structural diagram of an integrated device in which another embodiment of the integrated device is shown and a magnetic core is formed in a U shape.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Integrated device 10 Magnetic core 10-1 Upper core 10-2 Lower core 10-5 Central pillar 10-6R, 10-6L Side pillar 10-7R, 10-7L Opening part 20 Single-sided flexible board 30 Double-sided flexible board 40 Magnetic material layer

Claims (10)

An integrated device for integrating passive elements,
A first flexible substrate wound around a magnetic core and having a copper layer on the surface;
Between the first flexible substrate and the second flexible substrate, a second flexible substrate wound around the magnetic core so as to surround the outermost peripheral surface of the first flexible substrate and having a copper layer on the surface A layer of the magnetic material interposed between
An integrated device comprising: The first flexible substrate has two or more copper layers insulated from each other.
The integrated device according to claim 1. The magnetic core is provided in a path of magnetic flux that intersects perpendicularly to the winding surfaces of the first flexible substrate and the second flexible substrate,
The integrated device according to claim 1, wherein A part of the magnetic core has an air gap for adjusting the excitation inductance value.
The integrated device according to claim 1, wherein the integrated device is a device. The magnetic core is composed of a combination of a first magnetic core and a second magnetic core both having an E shape,
The first flexible substrate, the magnetic material layer, and the second flexible substrate are all wound around a central magnetic core column among the three magnetic core columns included in the combined body. Yes,
The integrated device according to claim 1, wherein the integrated device is a device. The magnetic core is composed of a combination of a first magnetic core and a second magnetic core, both of which are U-shaped,
The first flexible substrate, the magnetic material layer, and the second flexible substrate are all wound around one of two magnetic core pillars included in the combined body,
The integrated device according to claim 1, wherein the integrated device is a device. Each of the first flexible substrate and the second flexible substrate is wound on the same axis by one turn or multiple turns,
The integrated device according to claim 5, wherein the integrated device is any one of the following. Polyimide film is used for the first flexible substrate and / or the second flexible substrate,
The integrated device according to claim 1, wherein the integrated device is a device. Ferrite polymer is used for the magnetic material interposed between the first flexible substrate and the second flexible substrate,
The integrated device according to claim 1, wherein the integrated device is a device.   An LLC resonant converter having the integrated device according to any one of claims 1 to 9.