JP2007088131A - Transformer having flat structure and inductance element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transformer having a flat structure capable of being incorporated into a printed-circuit board, and to easily design a desired transformation ratio. <P>SOLUTION: In the transformer, recesses 1a to 1d for arranging one or a plurality of cores are formed to the printed-circuit board 1 while printed wirings for primary winding Pa to Pd and the printed wirings for secondary windings Sa to Sd are formed mutually around the recesses under an insulated state. Magnetic substances 3a to 3d formed on a magnetic-substance plate 3e are arranged in each recess. A plurality of the primary windings wired around each recess are connected in parallel or connected in series, and a plurality of the secondary windings wired around each recess are connected in series or connected in parallel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a transformer having a flat structure that can be incorporated into a printed circuit board, and further relates to an inductance element such as a reactor.

The conventionally known transformer has a configuration in which the primary and secondary windings are three-dimensionally wound around the magnetic core, and thus there is a limit to downsizing. In particular, it cannot be incorporated into a printed circuit board and becomes an external component. Therefore, it has become a bottleneck when promoting miniaturization in various electronic and electrical devices. For example, this problem cannot be solved even if it is made compact as shown in Patent Document 1 below.
JP 11-317314 A

On the other hand, the existence of a flat coil formed by printing the coil itself is known. However, since the number of turns of the printed coil is limited, it is difficult to design the printed coil so as to obtain a desired inductance.

The present invention has been made in view of the above points, and an object of the present invention is to provide a transformer having a flat structure that can be incorporated into a printed circuit board. It is another object of the present invention to provide a flat structure transformer that can be easily designed to obtain a desired transformation ratio. It is another object of the present invention to provide an inductance element having a flat structure that can be easily designed to obtain a desired inductance.

In the transformer according to the present invention, one or a plurality of core placement recesses are formed, and the primary winding printed wiring and the secondary winding printed wiring are provided in an insulated state around the recess. And a magnetic core disposed in each of the recesses. Thereby, a transformer having a flat structure that can be incorporated into a printed circuit board can be provided. Therefore, since the transformer can be incorporated into the printed circuit board without using external parts, the circuit configuration in various electronic and electrical devices can be reduced in size.

In a preferred embodiment of the transformer according to the present invention, a plurality of primary windings wired around a plurality of the recesses are connected in parallel to a primary voltage source, and a wiring around the plurality of the depressions is provided. The plurality of secondary windings connected in series are connected in series to output a secondary voltage. This facilitates the design to obtain the desired boosted transformation ratio.
In another preferred embodiment, a plurality of the primary windings wired around a plurality of the recesses are connected in series to a primary voltage source, and a plurality of the wirings wound around the plurality of the depressions are provided. Secondary windings are connected in parallel to output secondary voltage. This facilitates the design to obtain the desired reduced transformer ratio.

The inductance element of the flat structure according to the present invention is formed with a plurality of recesses for arranging the cores, and winding wirings are provided around each of the recesses, and the windings are connected in series or in parallel. A printed circuit board configured to be configured as one inductance element by being connected, and a magnetic core disposed in each of the recesses. This makes it easy to design a flat structure inductance element so as to obtain a desired inductance by the number of windings in each core and the combination of each winding in series connection or parallel connection.

FIG. 1 is a diagram conceptually showing one embodiment of the present invention, and is a plan view partially showing a portion where a transformer is arranged in a printed circuit board 1. In order to facilitate understanding, FIG. 1A shows only the printed wiring P for the primary winding, and FIG. 1B shows only the printed wiring S for the secondary winding. These show the same planar portion of the printed circuit board. Further, for the sake of simplification of illustration, the printed wirings P and S are drawn as simple diagrams, but the actual state is a known printed wiring form having an appropriate line width. Further, in the figure, the connection portions of the printed wiring are shown with dots. Accordingly, in the figure, if the wiring is crossed and no dot is attached, it is a non-connected part, and the printed wiring crosses insulatively by a known method such as a bridge.

In the printed circuit board 1, the recesses 2a, 2b, 2c, and 2d for arranging the magnetic cores of the transformer are provided by the number of cores in the transformer. In the illustrated example, four dents 2a to 2d are provided, but more dents may be provided depending on the design of the transformer, or only one may be provided in the smallest case. In the most preferred embodiment, the recesses 2 a to 2 d are formed of through holes penetrating the substrate 1. However, it is not limited to the through hole, and any recess that can properly accommodate the core may be used.

A printed wiring of primary windings Pa, Pb, Pc, Pd is provided around each of the recesses 2a to 2d as shown in FIG. 1 (a), and a secondary wiring is provided as shown in FIG. 1 (b). Printed wiring of the windings Sa, Sb, Sc, Sd is provided. Accordingly, the primary windings Pa to Pd and the secondary windings Sa to Sd provided around the same recesses 2a to 2d are disposed on the substrate 1 so as to overlap each other. Printed wiring so as to maintain the insulation state. For this purpose, a known multilayer substrate manufacturing technique may be used. Alternatively, the primary windings Pa to Pd and the secondary windings Sa to Sd may be separately printed on the front and back surfaces of the circuit board 1 without being limited to the multilayer board. Alternatively, the primary windings Pa to Pd and the corresponding secondary windings Sa to Sd may be alternately arranged on one surface of the circuit board 1, that is, printed wiring like bifilar winding. In that case, the insulation state is maintained by the jump wiring at the point where the two wirings intersect. Of course, the printed circuit board 1 is also provided with other printed wiring, but details thereof are omitted. FIG. 1 shows an example in which a DC voltage + V is input to the printed circuit board 1, a predetermined AC signal is oscillated by an oscillator provided on the printed circuit board 1, and the oscillating AC voltage is transformed. . However, the present invention is not limited to this, and an arbitrary AC voltage may be directly input.

FIG. 2 shows an embodiment of the magnetic core 3 used in this transformer, (a) is a plan view, and (b) is a side view. The magnetic core portion 3 projects a plurality of cores 3a, 3b, 3c, 3d at a given height on the core base plate 3e in an arrangement corresponding to the recesses 2a to 2d provided on the printed circuit board 1. It is formed by. In the assembled state, the respective cores 3a to 3d on the core base plate 3e are fitted into the respective recesses 2a to 2d of the circuit board 1, and the corresponding primary windings Pa to Pd and the respective secondary windings Sa to Guarantees magnetic coupling of Sd.

FIG. 3 is a side sectional view showing a state where the magnetic core portion 3 is assembled to the printed circuit board 1. In this example, two magnetic core portions 3 as shown in FIG. 2 are used, and sandwiched between the two magnetic core portions 3 and 3 from both sides of the printed circuit board 1. In this case, the height of each of the cores 3 a to 3 d on the core base plate 3 e is substantially half of the thickness of the printed circuit board 1. However, the present invention is not limited thereto, and only one magnetic core portion 3 may be used so that the cores 3a to 3d are fitted into the recesses 2a to 2d from one side of the printed circuit board 1. Moreover, each core 3a-3d may be provided independently, and you may make it each fit in each dent 2a-2d individually. In the magnetic core portion 3, the cores 3a to 3d and the core base plate 3e are not integrally formed, and the cores 3a to 3d are attached and fixed to the core base plate 3e made of a magnetic material sheet. Good. Moreover, although the formation function of a magnetic circuit is inferior, as a modification, the core base plate 3e may be a nonmagnetic material.

FIG. 4 shows an equivalent circuit of the transformer shown in FIG. In this example, a plurality of primary windings Pa to Pd printed and wired around the plurality of recesses 2a to 2d are connected in parallel to the primary voltage source and wired around the plurality of recesses 2a to 2d. A plurality of secondary windings Sa to Sd are connected in series to output a secondary voltage. In this case, if the number of turns of each of the primary windings Pa to Pd and the secondary windings Sa to Sd is the same (turn ratio 1: 1), the transformer increases the voltage with a transformation ratio of 1: 4. Further, in combination with this, if the primary and secondary turns ratios are set appropriately, the transformation ratio (pressure increase ratio) can be further set and changed.

Contrary to the above example, a plurality of primary windings Pa to Pd are connected in series to a primary voltage source, and a plurality of secondary windings Sa to Sd are connected in parallel to output a secondary voltage. May be. In that case, it becomes a transformer that reduces the voltage at a transformation ratio of 4: 1. For example, an AC-DC converter (DC adapter) that obtains a desired DC voltage by reducing the commercial AC voltage and then performing AC-DC conversion, etc. Suitable for any use. Also in this case, if the primary and secondary turns ratios are appropriately set in combination with this, the transformation ratio (reduction ratio) can be further set / changed.

Furthermore, as a modified example, among a plurality of primary windings (or secondary windings) on the same primary side (or secondary side), some are connected in parallel and the rest are connected in series. Various combinations are possible. Such a combination is suitable for obtaining a non-integer transformation ratio, for example.

As described above, the number of cores, that is, the number of the recesses 2a to 2d is arbitrary, and the number of turns (turn ratio) of the primary winding and / or the secondary windings Sa to Sd corresponding to each core (depression) is also respectively set. It is optional and may be set appropriately in design. Further, the form of serial connection or parallel connection of the primary side and the secondary side, and combinations thereof are also arbitrary, and these may be set as appropriate in design. Thus, the turns ratio of each primary winding and each secondary winding that make a pair, and the series connection (or parallel connection) that makes a pair with the primary side connected in parallel (or connected in series) ) A desired transformation ratio can be realized by appropriately setting the number of secondary windings (number of cores).

Further, the primary windings Pa to Pd and the secondary windings Sa to Sd forming a pair are not limited to the example in which the primary windings Pa to Pd and the secondary windings Sa to Sd are provided around the common recesses 2a to 2d, respectively. The primary winding may be printed around and the secondary winding printed around the other recess.

The idea shown in the above embodiment can also be applied to an inductance element such as a reactor. That is, windings are formed with flat printed wiring around a plurality of recesses formed on the printed circuit board, and these windings are connected in series connection or parallel connection or a combination of series and parallel, and each recess is connected. By arranging the magnetic core, an inductance element such as a reactor having a desired inductance can be provided in a flat structure.

  That is, when the inductance element of such a flat structure is summarized and described with reference to the reference numerals in the above-described embodiments, the inductance element of the flat structure includes a plurality of recesses (2a to 2d) for core arrangement. Is formed, and a printed wiring of windings (Pa to Pd or Sa to Sd) is provided around each recess, and each winding is configured as one inductance element by being connected in series or in parallel. The printed circuit board (1) configured as described above and the magnetic cores (3a to 3d) disposed in the recesses are provided, and the magnetic cores (3a to 3d) are connected to the magnetic core base plate (3e). ) Through magnetic coupling. This makes it easy to design a flat structure inductance element so as to obtain a desired inductance by the number of windings in each core (3a to 3d) and the combination of each winding in series connection or parallel connection. .

The top view which shows one Example of this invention notionally. One Example of the magnetic body core part used with the transformer of the Example is shown, (a) is a top view, (b) is a side view. Side surface sectional drawing which shows the state which assembled the magnetic body core part to the printed circuit board of the Example. The equivalent circuit of the transformer shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed circuit board P Printed wiring S for primary windings Printed wiring 2a, 2b, 2c, 2d for secondary windings Indentation Pa, Pb, Pc, Pd Primary windings Sa, Sb, Sc, Sd Secondary Winding

Claims (11)

A printed circuit board in which one or a plurality of core placement recesses are formed, and a printed wiring of a primary winding and a printed wiring of a secondary winding are provided around each of the recesses in an insulated state;
A flat transformer having a magnetic core disposed in each of the recesses. A plurality of primary windings wired around a plurality of the recesses are connected in parallel to a primary voltage source, and a plurality of secondary windings wired around the plurality of the depressions are connected in series. The transformer according to claim 1, which outputs a secondary voltage. A plurality of primary windings wired around a plurality of the recesses are connected in series to a primary voltage source, and a plurality of secondary windings wired around the plurality of the depressions are connected in parallel. The transformer according to claim 1, which outputs a secondary voltage. The transformer according to claim 1, wherein the plurality of magnetic cores are formed on a common core base plate. The transformer according to claim 1, wherein the recess is a through hole formed in the printed circuit board. The transformer according to claim 1, wherein the printed circuit board is a multilayer printed circuit board. The transformer according to any one of claims 1 to 6, wherein the primary winding and the secondary winding forming a pair are formed around the same recess. A pair of primary winding and secondary winding are respectively formed around adjacent recesses, and magnetic cores disposed in the adjacent recesses are connected via a magnetic body. The transformer in any one of 6. The plurality of magnetic cores arranged in the depression of the printed circuit board and the surrounding portions of the printed circuit board are sandwiched by magnetic plates from both sides of the printed circuit board. The transformer in any one of 1 thru | or 8. A plurality of core placement recesses are formed, and a printed wiring of a winding is provided around each recess, and each winding is configured as one inductance element by being connected in series or in parallel. A printed circuit board,
A flat structure inductance element comprising a magnetic core disposed in each of the recesses. The inductance element according to claim 10, wherein each of the magnetic cores is magnetically coupled via a magnetic core base plate.

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