JP2014063856A - Composite magnetic component and switching power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite magnetic component compounding a transformer for power transmission, and a resonance inductor connected in series equivalently with the primary coil or secondary coil of the transformer for power transmission.SOLUTION: The magnetic core of a composite magnetic component includes first and second external magnetic legs arranged at both ends, and first and second internal magnetic legs. A resonance inductor is formed by magnetic flux passing through the first internal magnetic leg, a power transmission transformer is formed by magnetic flux passing through the second internal magnetic leg, and the resonance inductor is connected in series equivalently with the primary coil or secondary coil of the transformer for power transmission. One of the primary coil or secondary coil of the transformer for power transmission forms an equivalently series connection circuit with the resonance inductor, by winding at least one turn of coil around both the first and second internal magnetic legs.

Description

  The present invention relates to a composite magnetic component in which a transformer and an inductor are combined.

  Attempts to construct a plurality of magnetic parts substantially by using a magnetic core formed by fitting a pair of magnetic materials and a coil wound around the magnetic core are aimed at reducing the component cost, mounting cost, and downsizing. The effect has been recognized and various proposals have already been made.

  FIG. 15 shows a composite magnetic component disclosed in Japanese Patent No. 2770750 which is a first conventional example. In the figure, reference numeral 1 denotes a coil body formed by laminating a plurality of thin-layer substrates 2 having the same shape. Each thin-layer substrate 2 has a pair of main leg through-holes 4, 4 a in the lateral direction of the central through-hole 3. Provided. In common with the thin-layer substrate 2, a plurality of plated through holes 5, 6, 7, and 8 serving as conductive connecting portions are provided in front of one main leg through hole 4, and the other side is correspondingly provided. A plurality of plated through holes 5a, 6a, 7a, 8a, which are conductive connection portions, are provided in front of the main leg through hole 4a. Further, a plurality of plated through holes 9 and 9a each serving as a connecting portion are provided behind each main leg through hole 4 and 4a, and a plated through hole 10 serving as a connecting portion is also provided behind the central through hole 3. These plated through holes 5 to 10 and 5a to 10a make electrical connection between the outside and the thin substrate 2. The coil body 1 includes a first coil part 11 and a second coil part 11a. That is, when viewed from the center of the central through hole 3, the first coil portion 11 is provided on one main leg through hole 4 side, and the second coil portion 11a is provided on the other main leg through hole 4a side. The first and second coil portions 11 and 11a are configured by forming a first conductive pattern 12 and a second conductive pattern 12a on a common thin layer substrate 2, respectively. The first conductive pattern 12 includes two systems, a primary circuit pattern 14 that finally becomes the primary winding of the first transformer 13 and a secondary circuit pattern 15 that becomes the secondary winding of the first transformer 13. These are formed on different thin layer substrates 2. The second conductive pattern 12a is also composed of two systems, a primary circuit pattern 14a that is a primary winding of the second transformer 13a and a secondary circuit pattern 15a that is a secondary winding of the second transformer 13a. These are also formed on different thin layer substrates 2.

  Next, the configuration of the magnetic core 41 attached to the coil body 1 will be described. The magnetic core 41 includes a first magnetic core 42 provided corresponding to the first coil portion 11 and a second magnetic core 42a provided corresponding to the second coil portion 11a. The first magnetic core 42 is configured by a pair of an upper magnetic material 43 and a lower magnetic material 44 each having an E-shaped side, and the second magnetic core 42a also has a side portion. Both are configured by abutting together a pair of upper magnetic material 43a and lower magnetic material 44a that form an E shape. Each of the upper magnetic member 43 and the lower magnetic member 44 is provided with a main leg 45 inserted into the main leg through hole 4 and side legs 46 and 47 located on both sides of the main leg 45. Similarly, the upper magnetic member 43a and the lower magnetic member 44a are also formed with a main leg 45a inserted into the main leg through hole 4a and side legs 46a and 47a located on both sides of the main leg 45a. The upper magnetic members 43 and 43a are integrally formed as the upper magnetic member 48 by connecting one of the side legs 46 and 46a. The lower magnetic members 44 and 44a are also integrally formed as a lower magnetic member 49 by connecting one of the side legs 46 and 46a. The side legs 46 and 46a of the integrated first and second magnetic cores 42 and 42a are inserted into the central through hole 3, and the plated cores 1 are attached to the plated through holes 5 with the magnetic core 41 attached to the coil body 1. ˜10, 5a˜10a are exposed from the magnetic core 41 for electrical connection between the external substrate and the thin layer substrate 2. In the first conventional example, the first and second coil portions 11 obtained by forming the first and second conductive patterns 12 and 12a on each common thin layer substrate 2 and laminating the thin layer substrates 2 are used. , 11a, a pair of magnetic cores 41 is mounted, so that two first and second transformers 13, 13a, in which the primary side and the secondary side are respectively connected in series, are manufactured.

  FIG. 16 shows a composite magnetic component disclosed in Japanese Unexamined Patent Application Publication No. 2009-189144, which is a second conventional example. A magnetic core provided with four magnetic legs as shown in FIG. 16 is provided, and a primary winding is wound around the two inner magnetic legs of the magnetic core, and around one of the inner magnetic legs. The first secondary winding is wound, and the second secondary winding is wound around the other inner magnetic leg to constitute a transformer. Four magnetic legs are provided in parallel at intervals on a bottom plate made of a magnetic material. The first secondary winding Ns1 is wound around one of the two magnetic legs provided on the inner side, and the second secondary winding Ns2 is wound around the other magnetic leg. Further, the primary winding Np is wound so as to cover the secondary windings Ns1 and Ns2 from the outside.

  FIG. 17 shows a composite magnetic component disclosed in Japanese Patent Laid-Open No. 2000-260639, which is a third conventional example. A, B, C, and D in FIG. 17 are plan views of the stacked double-sided boards, and printed coils are drawn on the respective layers in the pattern of the board. A magnetic core 6 is inserted into a magnetic core insertion hole provided in the multilayer substrate. The magnetic core 6 includes a total of three magnetic legs: a first external magnetic leg 6a, a second external magnetic leg 6c, and an internal magnetic leg 6b. The first transformer is constructed by winding a primary coil and a secondary coil around the inner magnetic leg 6b in a spiral shape, whereas the second transformer is constituted by a first outer magnetic leg 6a and a second outer coil. A primary coil and a secondary coil are configured by connecting in series a coil with the same number of turns to the magnetic leg 6c. With this configuration, the induced voltage due to the first transformer is not output to the second transformer, and the induced voltage due to the second transformer is not output to the first transformer. The first and second transformers can be apparently operated as mutually independent transformers.

Japanese Patent No. 2770750 JP2009-189144 JP2000-260639

  The magnetic core used in the composite magnetic parts of the first conventional example and the second conventional example has five legs in the first conventional example and four legs in the second conventional example between both end surfaces of the bottom plate made of a magnetic material. If the design is made so that the total of the iron loss and the copper loss is minimized, the magnetic leg is inevitably elongated. On the other hand, since a typical ferrite as a soft magnetic material used for a magnetic core contracts during firing, the dimensional error of the magnetic core in the longitudinal direction becomes large if the shape is elongated. For example, when using a printed coil that draws a coil in the pattern of the board, the magnetic leg insertion hole of the magnetic core provided on the board requires a design that can be inserted without any problem with either the maximum core or the minimum core. If the dimensional error of the magnetic core is large, an extra space is required, which is a problem in terms of miniaturization and high efficiency. Also, the elongated magnetic core has a problem that it is easily broken by impact.

  In the composite magnetic parts of the first conventional example and the second conventional example, the magnetic flux passing through each magnetic leg is not uniform in the operating state of the switching power supply. For example, in the second conventional example, the magnetic legs are arranged in a line in the order of the first external magnetic leg, the first internal magnetic leg, the second internal magnetic leg, and the second external magnetic leg. The distance from the first internal magnetic leg to the first and second external magnetic legs is not uniform, and similarly the distance from the second internal magnetic leg to the first and second external magnetic legs is not uniform. . Furthermore, since the currents flowing through the coils wound around the first and second internal magnetic legs are different, the magnetic flux density becomes non-uniform as a result. For this reason, it is assumed that only one of the external magnetic legs has a large magnetic core loss, and only one of the external magnetic legs is magnetically saturated, which is difficult to design. Further, since the magnetic paths between the first internal magnetic leg and the second external magnetic leg and between the second internal magnetic leg and the first external magnetic leg are long, the iron loss is increased correspondingly.

  Further, if the magnetic flux passing through the first and second external magnetic legs is uniform, the first and second external magnetic legs are turned in the opposite direction in the same direction as shown in Japanese Patent Laid-Open No. 2000-260639 of the third conventional example. If a wound coil is connected in series to form a primary coil and a secondary coil, a transformer that can be regarded as independent of the power transmission transformer can be configured, and used for signal transmission between the primary and secondary, for example. It cannot be constituted by the composite magnetic parts of the first and second conventional examples in which the magnetic flux passing through each magnetic leg is not uniform.

  The composite magnetic parts of the first conventional example and the second conventional example have switching power supply topologies suitable for each, and are applied to a two-transactive clamp converter in the first conventional example and a boost half-bridge converter in the second conventional example. Is introduced, but may not be suitable. For example, in an LLC resonant converter known as a high-efficiency topology, the ratio Lm / Lr between the transformer exciting inductance Lm and the resonant inductor inductance Lr is generally set to about 3 to 10. In the first conventional example and the second conventional example, the cross-sectional areas of the two internal magnetic legs are equal, and the number of windings of the coil wound around each internal magnetic leg is also drawn equally. The inductance ratio can only be 1.

  The composite magnetic component according to the present invention is a magnetic core formed by fitting a pair of magnetic materials, a pair of bottom plates positioned substantially parallel to each other, and a first external member disposed at both ends of the bottom plate. A magnetic leg, a second external magnetic leg, and a first internal magnetic leg and a second internal magnetic leg arranged at substantially equal distances from the first external magnetic leg and the second external magnetic leg, A resonance inductor is formed by the magnetic flux passing through the first internal magnetic leg, and a power transmission transformer is formed by the magnetic flux passing through the second internal magnetic leg. In a composite magnetic component in which a resonant inductor is connected in series with a primary coil or a secondary coil of a power transmission transformer, one of the primary coil or the secondary coil of the power transmission transformer is a multi-turn coil. Of the coils of each turn connected in series to form the coil, at least one coil is wound around both the first internal magnetic leg and the second internal magnetic leg so as to be equivalent to the resonant inductor. A series connection circuit is formed, and the other of the primary coil and the secondary coil of the power transmission transformer is wound around only the second internal magnetic leg.

  In addition, since the cross-sectional areas of the first internal magnetic leg and the second internal magnetic leg are designed according to the inductance value and the operating magnetic flux density required for the resonant inductor and the power transmission transformer, they do not necessarily have to be equal. Further, if the gap length of the gap provided in the magnetic path passing through the first internal magnetic leg is equal to the gap length provided in the magnetic path passing through the second internal magnetic leg, the gap can be processed in one process, thereby reducing the processing cost. it can. Furthermore, if a coil in which a series connection circuit with an inductor is equivalently formed of the primary coil or the secondary coil of the power transmission transformer is formed by a printed coil based on the pattern of the board, a complicated winding structure can be obtained. However, the bobbin structure and the winding process are not complicated, and the cost can be reduced.

  Further, when a 0.5-turn coil is required for the power transmission transformer in order to secure an optimum voltage used in the control circuit and the switch driving circuit with low loss, the following configuration is provided. As a first method, the second internal magnetic leg is divided into two substantially in the same cross-sectional area with a gap, and the coil is wound once around one of the two divided magnetic legs. Form a 5-turn transformer coil. Another method is to divide the first internal magnetic leg into two substantially the same cross-sectional area with a gap, and either one of the divided first internal magnetic legs or the second external magnetic legs. The coil is wound once around one side to form a substantially 0.5 turn coil.

  When it is necessary to transmit any signal across the primary-secondary insulation barrier, the same number of coils wound around the first external magnetic leg and the first external magnetic leg in the opposite direction. Are connected in series to form a primary coil and a secondary coil, respectively, so that it is possible to obtain a power transmission transformer and a signal transmission transformer that can be regarded as substantially independent from the resonant inductor.

  The magnetic core of the composite magnetic component has a first opening surface on the first internal magnetic leg side to connect the primary coil and primary circuit of the power transmission transformer, and the secondary coil and secondary circuit of the power transmission transformer, A second opening surface is provided on the second internal magnetic leg side. When the resonant inductor is equivalently connected in series with the primary coil of the power transmission transformer, the composite magnetic component is arranged with the first opening surface facing the primary circuit side and the second opening surface facing the secondary circuit side. Thus, the primary coil and the primary circuit of the power transmission transformer are connected via the first opening surface, and the secondary coil and the secondary circuit of the power transmission transformer are connected via the second opening surface. On the contrary, when the resonant inductor is connected in series with the secondary coil of the power transmission transformer, the first opening surface is disposed on the secondary circuit side and the second opening surface is disposed on the primary circuit side. The secondary coil and the secondary circuit of the power transmission transformer are connected through the first opening surface, and the primary coil and the primary circuit of the power transmission transformer are connected through the second opening surface. With this arrangement, the input / output wiring of the composite magnetic component can be shortened, so that conduction loss can be reduced.

  The composite magnetic component of the present invention is applied to a switching power supply apparatus, and zero voltage switching is performed on a switching element of a primary or secondary circuit by LC resonance operation using a resonant inductor constituted by a magnetic flux passing through a first internal magnetic leg. Or, zero current switching is used to reduce switching loss and reduce noise.

(1) In the present invention, since a magnetic component in which an inductor is connected in series with a primary coil or a secondary coil of a power transmission transformer can be composed of a pair of magnetic materials and a plurality of coils, the component cost is reduced. This is effective in reducing mounting costs and downsizing of magnetic components.
(2) Since the composite magnetic component of the present invention can be formed in a shape closer to the vertical and horizontal dimensions than the composite magnetic components of the first and second conventional examples in which the magnetic legs are arranged in a row, the first and second (2) The dimensional error of the ferrite core is smaller than that of the conventional example, and it can be designed to be hard to break, and there are few restrictions on mounting.
(3) The cross-sectional area of the first and second internal magnetic legs, the number of turns of the coil wound around the first and second internal magnetic legs, and the magnetic path via the first and second internal magnetic legs Depending on the gap provided, the inductance of the resonant inductor, the excitation inductance of the power transmission transformer, and the operating magnetic flux density between the resonant inductor and the power transmission transformer can be optimally designed.
(4) Since the distance from the first and second internal magnetic legs to the first and second external magnetic legs is short and uniform, the iron loss is small, the design relating to the core loss and magnetic saturation is easy, and the first A primary coil and a secondary coil are formed by connecting in series the same number of coils wound in the opposite direction around the external magnetic leg and the second external magnetic leg, thereby substantially independent of the power transmission transformer and the inductor. It is possible to obtain a signal transmission transformer that can be regarded as “a”.
(5) Input / output of composite magnetic parts by placing the first internal magnetic leg close to the side where the inductor is connected in series with the coil of the power transmission transformer in the primary and secondary circuits of the isolated switching power supply Therefore, the conduction loss can be reduced.
(6) The LC resonance operation using the inductor constituted by the present invention as a resonant inductor reduces the switching loss and noise by switching the primary or secondary circuit switch element to zero voltage or zero current. realizable.

It is a figure for demonstrating the magnetic core 61 in 1st Example of this invention. 1A1 is a front view of the E-type magnetic material E1, and FIG. 1A2 is a plan view of the E-type magnetic material E1. 1B1 is a front view of the I-type magnetic material I1, and FIG. 1B2 is a plan view of the I-type magnetic material I1. FIG. 1C is a front view of the magnetic core 61. It is the multilayer substrate 71 in 1st Example of this invention. 2A is a plan view of the multilayer substrate 71, and FIG. 2B is a front view showing the multilayer substrate 71 in an exploded manner. It is the figure which showed the direction of the electric current in each layer, and the direction of a magnetic field while showing the coil pattern formed in each layer of A, B, C, D of the multilayer board | substrate 71. FIG. It is an equivalent circuit diagram of the transformer T1 in the first embodiment of the present invention. It is the figure which showed the LLC resonance half bridge converter which comprises the power converter circuit in 1st Example of this invention. It is a figure for demonstrating the magnetic core 62 in 2nd Example of this invention. 6A1 is a front view of the first E-type magnetic material E2A, and FIG. 6A2 is a plan view of the first E-type magnetic material E2A. 6B1 is a front view of the second E-type magnetic material E2B, and FIG. 6B2 is a plan view of the second E-type magnetic material E2B. FIG. 6C is a front view of the magnetic core 62. It is the multilayer substrate 72 in 2nd Example of this invention. FIG. 7A is a plan view of the multilayer substrate 72, and FIG. 7B is an exploded front view of the multilayer substrate 72. FIG. It is the figure which showed the direction of the electric current and magnetic field in each layer while showing the coil pattern formed in each layer of A, B, C, D of the multilayer substrate 72. It is an equivalent circuit diagram of the transformer T1 in the second embodiment of the present invention. It is the figure which showed the active clamp voltage doubler rectifier converter which comprises the power converter circuit in 2nd Example of this invention. It is a figure for demonstrating the 1st magnetic core 63A in 3rd Example of this invention. FIG. 11A1 is a front view of the E-type magnetic material E3A, and FIG. 11A2 is a plan view of the E-type magnetic material E3A. FIG. 11B1 is a front view of the I-type magnetic material I3, and FIG. 11B2 is a plan view of the I-type magnetic material I3. FIG. 11C is a front view of the magnetic core 63A. It is the figure which showed the coil pattern wound around the magnetic core 63A in 3rd Example of this invention. It is a figure for demonstrating the magnetic core 63B in the modification of 3rd Example of this invention. FIG. 13A1 is a front view of the E-type magnetic material E3B, and FIG. 13A2 is a plan view of the E-type magnetic material E3B. FIG. 13B1 is a front view of the I-type magnetic material I3, and FIG. 13B2 is a plan view of the I-type magnetic material I3. FIG. 13C is a front view of the magnetic core 63B. It is the figure which showed the coil pattern wound around the magnetic core 63B in the modification of 3rd Example of this invention. It is the figure which showed the 1st prior art example. It is the figure which showed the 2nd prior art example. It is the figure which showed the 3rd prior art example.

<< First Example >>
FIG. 1 is a view for explaining a magnetic core 61 in the first embodiment of the present invention. It is formed by fitting the E-type magnetic material E1 of FIGS. 1 (a1) and 1 (a2) with the I-type magnetic material I1 of FIGS. 1 (b1) and 1 (b2) and fixing them with an adhesive or the like. In the magnetic core 61 shown in FIG. 1 (c), a pair of bottom plates BSP1 and BSP2 positioned substantially parallel to each other, a first external magnetic leg OL1 disposed at both ends of the bottom plate BSP1, and a second external plate The magnetic leg OL2 is provided with a first internal magnetic leg IL1 and a second internal magnetic leg IL2 arranged at substantially equal distances from the first external magnetic leg OL1 and the second external magnetic leg OL2.

  FIG. 2 shows a multilayer substrate 71 according to the first embodiment of the present invention, and the multilayer substrate 71 includes a plurality of magnetic leg through holes. The first and second external magnetic legs OL1 and OL2 of the E-type magnetic material E1 are the first and second magnetic leg through holes HOLE1 and HOLE2, and the first and second internal magnetic legs IL1 and IL2 are the third and fourth. Are passed through the magnetic leg through holes HOLE3 and HOLE4 and fitted with the I-type magnetic material I1. The fitted magnetic core 61 includes a first opening surface OF1 on the first internal magnetic leg IL1 side and a second opening surface OF2 on the second internal magnetic leg IL2 side. In the multilayer substrate 71, the conductor pattern layer is composed of four layers A, B, C, and D. The B layer and the C layer are formed on both sides of the thin plate substrate, and the prepreg PP is sandwiched between the A layer-B layer and the C layer-D layer, and the thin plate substrate, the substrate on which the A layer is formed, and the D layer are formed. A substrate is laminated. The pattern of each layer is electrically connected by the inner via hole IVH penetrating the B layer-C layer and the through hole TH penetrating all the layers. A composite magnetic component IMAG1 is formed by the coil pattern formed in each layer and the magnetic core 61 fitted together. In addition to forming the composite magnetic component IMAG1, the multilayer substrate 71 includes an input terminal and an output terminal, and a large number of electronic components are mounted on the front and back surfaces to constitute the switching power supply 81 as a whole. The primary circuit is arranged on the input terminal side, and the secondary circuit is arranged on the output terminal side, and the composite magnetic component IMAG1 is arranged with the first opening surface OF1 facing the primary circuit side and the second opening surface OF2 facing the secondary circuit side. Is done.

  FIGS. 3A to 3D are views of coil patterns formed on the layers A, B, C, and D as viewed from the plane direction for each layer, and are intermediately connected by the inner via hole IVH. The coil patterns of the B layer and the C layer form the primary coil Np, and the coil patterns of the A layer and the D layer in which the intermediate tap is formed by the through hole TH form the first and second secondary coils Ns1, Ns2. .

  In the composite transformer of the present invention, for example, the number of turns of the primary coil Np is counted as follows. The primary coil Np passes through the B layer twice between the first external magnetic leg OL1 and the first internal magnetic leg IL1, and between the second external magnetic leg OL2 and the first internal magnetic leg IL1, B It passes twice in total, once in the layer and once in the C layer. For this reason, the primary coil Np is wound around the first internal magnetic leg IL1 by two turns. Similarly, the primary coil Np passes between the first external magnetic leg OL1 and the second internal magnetic leg IL2 for a total of 6 times, 3 times for the B layer and 3 times for the C layer. The second external magnetic leg OL2 And the second internal magnetic leg IL2 pass through the B layer three times and the C layer three times in total, six times in the opposite direction. Therefore, the primary coil Np is wound around the second internal magnetic leg IL1 for 6 turns.

  The primary coil Np is a 6-turn coil connected in series, and a 2-turn coil is wound around both the first internal magnetic leg IL1 and the second internal magnetic leg IL2, and is equivalent to the primary coil Np. A series connection circuit with a resonant inductor is formed. On the other hand, the first and second secondary coils Ns1, Ns2 are wound around only the second internal magnetic leg IL2. When a current in the direction indicated by the arrow starts to flow through the primary coil Np, a magnetic field in a direction corresponding to the right-handed screw law is generated. Since the first and second secondary coils Ns1 and Ns2 flow current in a direction that prevents a change in the magnetic field generated in the second internal magnetic leg IL2, the second internal magnetic leg IL2 acts as a transformer.

  By configuring the coils as shown in FIGS. 3A to 3D, the equivalent circuit of the composite magnetic component IMAG1 becomes as shown in FIG. 4, and the resonant inductor is connected in series with the primary coil of the transformer having the exciting inductance Lm. Lr is connected. Since the leakage inductance of the transformer exists in series with the resonant inductor Lr, the transformer leakage inductance is substantially included in the operation.

  FIG. 5 is a circuit diagram of the power conversion circuit of the first embodiment using the topology of the LLC resonant half-bridge converter, where Vin is a DC input power source, Cf1 and Cf2 are smoothing capacitors, Q1 and Q2 are switch elements, and Cr1 is a resonance. Capacitor, Lr is a resonant inductor, T1 is a first transformer, Np is a primary coil, Ns1, Ns2 are first and second secondary coils, and IMAG1 is a composite of a resonant inductor Lr and a first transformer T1 Composite magnetic component. SR1 and SR2 are synchronous rectifiers, and Load is a load device that outputs an output voltage Vout. R1 and R2 are resistors, AMP1 is an error amplifier, Vref1 is a reference voltage, and ISO is an isolated signal transmission element formed of a photocoupler or the like to form a feedback loop. CNTP and CNTS are primary and secondary control circuits. Although the description of the power conversion operation is omitted, the LLC resonant converter requires a resonant inductor Lr in series with the primary coil Np of the transformer for highly efficient power conversion. In the present invention, the transformer and the resonant inductor can be configured as one composite magnetic component IMAG1. In the LLC resonant converter, the ratio Lm / Lr of the exciting inductance Lm of the transformer and the inductance Lr of the resonant inductor is generally set to about 3 to 10, but in the present invention, the first and second internal magnetic legs are set. , The number of turns of the coil wound around the first and second internal magnetic legs, and the gap provided in the magnetic path passing through the first and second internal magnetic legs, the inductance Lr of the resonant inductor, The excitation inductance Lm of the power transmission transformer and the operating magnetic flux density between the resonant inductor and the power transmission transformer can be optimally designed. In the first embodiment, the first internal magnetic leg IL1 and the second internal magnetic leg IL2 of the E-type magnetic material E1 are processed to be shorter than the first external magnetic leg OL1 and the second external magnetic leg OL2. A gap is formed at the junction between the type magnetic material E1 and the type I magnetic material I1.

<< Second Embodiment >>
FIG. 6 is a view for explaining the magnetic core 62 in the second embodiment of the present invention. The first E-type magnetic material E2A shown in FIGS. 6 (a1) and 6 (a2) and the second E-type magnetic material E2B shown in FIGS. 6 (b1) and 6 (b2) are fitted together to form an adhesive or the like. In the magnetic core 62 shown in FIG. 6C, which is fixed by the first plate, a pair of bottom plates BSP1 and BSP2 positioned substantially parallel to each other, and first outer portions disposed at both ends of the bottom plates BSP1 and BSP2 The first internal magnetic leg IL1 and the second internal magnetic leg arranged at substantially equal distances from the magnetic leg OL1, the second external magnetic leg OL2, and the first external magnetic leg OL1 and the second external magnetic leg OL2. Leg IL2 is provided. Unlike the first embodiment, the second internal magnetic leg IL2 is formed in a columnar shape, and the first external magnetic leg OL1 and the second external magnetic leg OL2 are curved along the second internal magnetic leg IL2. This is a process for shortening the length of the circulating coil with respect to the cross-sectional area of the second internal magnetic leg IL2. Further, since both magnetic materials have the same E-shape, there is an advantage that only one type of mold for manufacturing the magnetic material is required.

  FIG. 7 shows a multilayer substrate 72 according to the second embodiment of the present invention, and the multilayer substrate 72 has a plurality of magnetic leg through holes. The first and second external magnetic legs OL1 and OL2 of the first and second E-type magnetic materials E2A and E2B penetrate through the first and second magnetic leg through holes HOLE1 and HOLE2, respectively. The internal magnetic legs IL1 and IL2 pass through the third and fourth magnetic leg through holes HOLE3 and HOLE4 and are fitted together. The fitted magnetic core 62 includes a first opening surface OF1 on the first internal magnetic leg IL1 side and a second opening surface OF2 on the second internal magnetic leg IL2 side. The multilayer substrate 72 is composed of four layers A, B, C, and D. The B layer and the C layer are formed on both surfaces of the thin plate substrate, and the prepreg PP is sandwiched between the A layer-B layer and the C layer-D layer. Laminated. The pattern of each layer is electrically connected by the inner via hole IVH penetrating the B layer-C layer and the through hole TH penetrating all the layers. A composite magnetic component IMAG2 is formed by the coil pattern formed in each layer and the magnetic core 62 fitted together. In addition to forming the composite magnetic component IMAG2, the multilayer substrate 72 includes an input terminal and an output terminal, and a large number of electronic components are mounted on the front and back surfaces to form the switching power supply 82 as a whole. A primary circuit is arranged on the side, and a secondary circuit is arranged on the output terminal side. Since the resonant inductor is connected in series with the secondary coil of the transformer, the composite magnetic component IMAG2 has the first opening surface OF1 on the primary circuit side and the second opening surface OF2 contrary to the first embodiment. Are arranged toward the secondary circuit side to shorten the input / output wiring.

  FIG. 8A to FIG. 8D are views of the coil patterns formed in the layers A, B, C, and D as seen from the plane direction for each layer, and A connected by the through hole TH. The coil pattern of the layer and the D layer forms the primary coil Np1 of the first transformer, and the coil pattern of the B layer and the C layer intermediately connected by the inner via hole IVH forms the secondary coil Ns1 of the first transformer. . The primary coil Np1 of the first transformer is wound four turns around only the second internal magnetic leg IL2. The secondary coil Ns1 of the first transformer is wound around both the first internal magnetic leg IL1 and the second internal magnetic leg IL2 among the 4-turn coils connected in series. Equivalently, a series connection circuit with a resonant inductor is formed. When a current in the direction indicated by the arrow begins to flow through the primary coil Np of the first transformer, a magnetic field in a direction corresponding to the right-handed screw law is generated. Since the secondary coil Ns1 of the first transformer passes a current in a direction that prevents a change in the magnetic field generated in the second internal magnetic leg IL2, the second internal magnetic leg IL2 acts as a transformer.

  Further, the composite magnetic component IMAG2 of the second embodiment includes a second transformer T2 that transmits a signal between the primary and the secondary in addition to the first transformer T1 that transmits the power between the primary and the secondary. And both operate substantially independently. The primary coil Np2 and the secondary coil Ns2 of the second transformer T2 are configured by connecting in series a coil having the same number of turns in the reverse direction to the first external magnetic leg OL1 and the second external magnetic leg OL2, Since the electromotive force generated by the first transformer T1 is canceled, it is not output to the second transformer T2. The second transformer T2 can be regarded as using a U-shaped magnetic core composed of the first and second external magnetic legs OL1, OL2 and the first and second bottom plates BSP1, BSP2. The primary coil Np2 of the second transformer T2 is drawn in the A layer, and forms a wiring portion that intersects with the jumper chip resistor JP1. The secondary coil Ns2 of the second transformer T2 is drawn in the B layer, and the wiring portion intersecting with the inner via hole IVH is formed in the C layer.

By configuring the coils as shown in FIGS. 8A to 8D, the equivalent circuit of the composite magnetic component IMAG2 is as shown in FIG. 9, and the resonant inductor is connected in series with the secondary coil of the transformer having the exciting inductance Lm. Will be connected. In the equivalent circuit, the secondary resonance inductor Lr is multiplied by a coefficient (Np / Ns) ² in order to convert it to the primary side. The transformer leakage inductance present in series with the resonant inductor is substantially contained in the resonant inductor.

  FIG. 10 is a circuit diagram of the power conversion circuit of the second embodiment using an active clamp on the primary side and a voltage doubler rectification on the secondary side, Vin is a DC input power source, Cac is a clamp capacitor, Cf2, Cf3, Cf4 Is a smoothing capacitor, Q1 and Q2 are switch elements, Lr is a resonant inductor, T1 is a first transformer, Np1 is a primary coil, and Ns1 is a secondary coil. T2 is a second transformer, Np2 is a primary coil, and Ns2 is a secondary coil. SR1 and SR2 are synchronous rectifiers, Lf1 is an output filter inductor, and Load is a load device that outputs an output voltage Vout. R1 and R2 are resistors and have a feedback loop (not shown). CNTP and CNTS are primary and secondary control circuits. Although description of the power conversion operation is omitted, in this topology, a resonant inductor Lr is required in series with the primary coil Np1 or the secondary coil Ns1 of the first transformer T1 in order to realize zero voltage switching. In the second embodiment, the secondary coil Ns1 is connected in series. In the present invention, the first transformer T1, the second transformer T2, and the resonant inductor can be configured as one composite magnetic component IMAG2. The second transformer T2 configured using a common magnetic core with the first transformer T1 is used for signal transmission between the primary control circuit CNTP and the secondary control circuit CNTS. For example, the synchronous rectifier elements SR1 and SR2 Can be used for transmission of drive timing.

<< Third embodiment >>
In a switching power supply apparatus to which the composite magnetic component of the present invention is applied, a DC voltage of about 10 V is generally required for a control circuit or a drive circuit for a switching element, but depending on design conditions, the surroundings of the second internal magnetic leg IL2 In some cases, a DC voltage of more than 20V may be obtained simply by rectifying and smoothing a coil wound for one turn, and in order to obtain a more suitable DC voltage, an application example in which a coil of 0.5 turns is provided in a transformer can be considered. In the third embodiment, in order to obtain a DC power source for comparatively low power use, two examples of a method of providing a 0.5-turn coil in the transformer are shown.

  FIG. 11 is a view for explaining the magnetic core 63A in the third embodiment of the present invention. 11 (c) formed by fitting the E-type magnetic material E3A of FIGS. 11 (a1) and 11 (a2) with the I-type magnetic material I3 of FIGS. 11 (b1) and 11 (b2). In the illustrated magnetic core 63A, a pair of bottom plates BSP1 and BSP2 positioned substantially parallel to each other, a first external magnetic leg OL1 and a second external magnetic leg OL2 disposed at both ends of the bottom plate BSP1, and a first A first internal magnetic leg IL1 and a second internal magnetic leg IL2 arranged substantially equidistant from the external magnetic leg OL1 and the second external magnetic leg OL2 are provided. The magnetic legs IL2-1 and IL2-2 having substantially the same cross-sectional area with a gap are formed. In the third embodiment, the first internal magnetic leg IL1 and the second internal magnetic leg IL2 of the E-type magnetic material E3A are processed to be shorter than the first external magnetic leg OL1 and the second external magnetic leg OL2. A gap is formed at the junction between the type magnetic material E3A and the type I magnetic material I3.

  FIGS. 12A and 12B show a method of forming a 0.5-turn coil in the transformer using the magnetic core 63A in the third embodiment of FIG. While the coil is wound around the second internal magnetic leg IL2 composed of the legs IL2-1 and IL2-2, the 0.5-turn coil is wound around only the magnetic leg IL2-1. Since the amount of magnetic flux passing through is halved, a voltage corresponding to 0.5 turns can be obtained.

  FIG. 13 is a view for explaining a magnetic core 63B in a modification of the third embodiment of the present invention. FIG. 13 (c), which is formed by fitting the E-type magnetic material E3B of FIGS. 13 (a1) and 13 (a2) and the I-type magnetic material I3 of FIGS. 13 (b1) and 13 (b2). In the illustrated magnetic core 63B, a pair of bottom plates BSP1 and BSP2 positioned substantially parallel to each other, a first external magnetic leg OL1 and a second external magnetic leg OL2 disposed at both ends of the bottom plate BSP1, and a first A first internal magnetic leg IL1 and a second internal magnetic leg IL2 arranged at substantially equal distances from the external magnetic leg OL1 and the second external magnetic leg OL2 are provided. The magnetic legs IL1-1 and IL1-2 having substantially the same cross-sectional area with a gap are formed.

  14 (a) and 14 (b) show a method of forming a 0.5 turn coil in the transformer using the magnetic core 63B in the modification of the third embodiment of FIG. The coil is wound around the second internal magnetic leg IL2, whereas the 0.5-turn coil is wound once around the first external magnetic leg OL1 and the magnetic leg IL1-1. As a result, a magnetic flux amount ½ of the magnetic flux passing through the second internal magnetic leg IL2 is obtained, and a voltage corresponding to 0.5 turns is obtained.

  It should be noted that the present invention can be applied to many applications other than those described above. For example, the shape of the magnetic core may be designed in a shape other than that shown in each embodiment, and each coil of the composite magnetic component is not a printed coil formed by a substrate pattern, but a bobbin using a winding machine. Each coil may be formed by winding a copper wire. The present invention can be applied to an insulation type switching power supply having a topology other than that shown in each embodiment, for example, an inverter.

61, 62, 63A, 63B ... magnetic core
71, 72 ... multilayer PCB
81, 82 ... switching power supply apparatus
E1, E2A, E2B, E3A, E3B ... E type core member
I1, I3 ... I type core member
BSP1 ... First base plate of the magnetic core
BSP2 ... second base plate of the magnetic core
OL1 ... first outer leg of the magnetic core
OL2 ... second outer leg of the magnetic core
IL1 ... 1st inner leg of the magnetic material (the first inner leg of the magnetic core)
IL1-1, IL1-2 ... The first inner legs of the magnetic core which are separated into 2 portions with a spacing)
IL2: second inner leg of the magnetic core (second inner leg of the magnetic core)
IL2-1, IL2-2 ... second inner legs of the magnetic core which are separated into 2 portions with a spacing)
HOLE1... First through-hole for the magnetic core (first through-hole for the magnetic core)
HOLE2 ... second through-hole for the magnetic core (second through-hole for the magnetic core)
HOLE3... Third through-hole for the magnetic core (third through-hole for the magnetic core)
HOLE4: Fourth through-hole for the magnetic core (fourth through-hole for the magnetic core)
A layer, B layer, C layer, D layer ... each conductor layer of multilayer board (layer-A, layer-B, layer-C, layer-D)
PP ... prepreg
IVH ... Inner via hole (through only thin double-sided board)
TH ... through-hole (through-hole)
JP1 ... Jumper chip resistor (jumper-wire-resistor)
OF1... First aperture surface OF2 facing the first internal magnetic leg IL1 side of the composite magnetic component... Second aperture surface Lr facing the second internal magnetic leg IL2 side of the composite magnetic component. Resonant inductor
Lf1 ... output-filter inductor
T1: First transformer (for power transmission) (first transformer)
IMAG1, IMAG2 ... Integrated magnetic component
Lm ... magnetizing inductance of the first transformer
T2 ... Second transformer (for signal transmission) (second transformer)
Np, Np1, Np2 ... Primary coil
Ns, Ns1, Ns2 ... secondary coil
Vin: DC input power supply, DC-input power supply
Vout ・ ・ ・ DC-output voltage
Cf1, Cf2, Cf3, Cf4: Smoothing capacitor Cr: Resonant capacitor
Cac ・ ・ ・ Clamp capacitor
Q1, Q2 ... switching element
SR1, SR2 ... Synchronous rectifier
Load ... load apparatus
R1, R2 ... resistors
AMP1... Error amplifier
Vref1 ... reference voltage source
ISO ・ ・ ・ Insulated signal transmission element (photocoupler, etc.)
CNTP ... Primary control circuit
CNTS ... secondary control circuit

Claims (9)

A magnetic core formed by fitting a pair of magnetic materials, a pair of bottom plates positioned substantially parallel to each other, a first external magnetic leg disposed at both ends of the bottom plate, and a second external magnet A first internal magnetic leg and a second internal magnetic leg arranged substantially equidistant from the first external magnetic leg and the second external magnetic leg;
A resonance inductor is formed by the magnetic flux passing through the first internal magnetic leg, and a power transmission transformer is formed by the magnetic flux passing through the second internal magnetic leg,
In the composite magnetic component comprising the resonance inductor connected in series with the primary coil or the secondary coil of the power transmission transformer,
One of the primary coil and the secondary coil of the power transmission transformer is a coil of at least one turn among the coils of each turn connected in series to form a coil of a plurality of turns. Wound around both of the second internal magnetic legs to equivalently form a series connection circuit with the resonant inductor;
The other of the primary coil and the secondary coil of the power transmission transformer is a composite magnetic component in which the coil is wound around only the second internal magnetic leg.   2. The composite magnetic component according to claim 1, wherein the first internal magnetic leg and the second internal magnetic leg have different cross-sectional areas.   A first gap is provided in the magnetic path passing through the first internal magnetic leg, and a second gap is provided in the magnetic path passing through the second internal magnetic leg, and the gap lengths of the first gap and the second gap are substantially equal. The composite magnetic component according to claim 1, wherein the composite magnetic component is equal to   The coil in which the series connection circuit with the resonant inductor is equivalently formed of the primary coil or the secondary coil of the power transmission transformer is a printed coil formed by a substrate pattern. The composite magnetic component according to any one of claims 1 to 3.   The magnetic core is formed by dividing the second internal magnetic leg into two substantially the same cross-sectional area with a gap therebetween, and around the magnetic leg of one of the two divided second internal magnetic legs. 5. The composite magnetic component according to claim 1, wherein the coil is wound once to form a substantially 0.5-turn coil in the power transmission transformer.   The magnetic core is formed by dividing the first internal magnetic leg into two substantially the same cross-sectional area with a gap, and either one of the first external magnetic leg or the second external magnetic leg; The coil is wound once around one of the magnetic legs of the first inner magnetic leg divided into two to form a substantially 0.5 turn coil in the power transmission transformer. The composite magnetic component according to any one of claims 1 to 4.   A primary coil and a secondary coil are configured by connecting in series the same number of coils wound in the opposite direction around the first external magnetic leg and the second external magnetic leg, respectively. The power transmission transformer and the resonant inductor are substantially included. 7. The composite magnetic component according to claim 1, wherein a signal transmission transformer that can be regarded as being independent is configured. A composite magnetic component according to any one of claims 1 to 7,
The magnetic core includes a first opening surface on the first internal magnetic leg side to connect the primary coil and the primary circuit of the power transmission transformer, the secondary coil and the secondary circuit of the power transmission transformer, and the second A second opening surface is provided on the inner magnetic leg side,
In the composite magnetic component, when a resonant inductor is connected in series with the primary coil of the power transmission transformer, the first opening surface is on the primary circuit side, and the second opening surface is on the secondary circuit side. And the primary coil of the power transmission transformer and the primary circuit are connected via the first opening surface, and the secondary coil and 2 of the power transmission transformer are connected via the second opening surface. The next circuit is connected,
On the other hand, when a resonant inductor is connected in series with the secondary coil of the power transmission transformer, the first opening surface is disposed on the secondary circuit side and the second opening surface is disposed on the primary circuit side. The secondary coil and the secondary circuit of the power transmission transformer are connected through the first opening surface, and the primary coil and the primary circuit of the power transmission transformer are connected through the second opening surface. Switching power supply device characterized by that. A composite magnetic component according to any one of claims 1 to 7,
A switching power supply device characterized in that a switching element of a primary circuit or a secondary circuit is subjected to zero voltage switching or zero current switching by an LC resonance operation in which the resonant inductor acts.

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