KR20180007177A - Double core planar transformer - Google Patents

Abstract

According to an embodiment of the present invention, there is provided a dual core planar transformer comprising: a core portion having a pair of cores magnetically coupled to each other; And a substrate portion disposed between the pair of cores, the substrate portion including a plurality of substrates formed with first through holes and second through holes, wherein the substrate is provided with first and second through holes A primary winding and a secondary winding formed in a double helix structure can be formed.

Description

{DOUBLE CORE PLANAR TRANSFORMER}

The present invention relates to a planar transformer, and more particularly to a dual core planar transformer.

Although the miniaturization of the transformer is made possible by increasing the switching frequency, the loss is increased due to a reduction in the heat dissipation area due to the miniaturization, and this loss increases proportionally with the increase of the switching frequency, and the winding- It is difficult to apply it to a power supply device having a high frequency switching frequency due to an increase in loss due to a skin effect and a proximity effect at a frequency. On the other hand, a planar transformer having a wide effective cross-sectional area can be used in a power supply device for a high frequency band by reducing a high frequency loss, thereby achieving miniaturization and high efficiency at the same time.

Conventionally, a conventional planar transformer implements a primary winding and a secondary winding on a laminated PCB to have the same characteristics as a wound-type transformer. However, if the number of windings increases, the number of stacked PCBs will increase in order to arrange them. This feature is the only disadvantage of a wound-type transformer.

FIG. 1 is a perspective view showing a planar transformer according to the prior art. FIG. 1 (a) is a perspective view showing the entire planar transformer, FIG. 1 (b) is a perspective view showing a state in which the core 1 is removed, (D) is a perspective view showing the primary winding and the secondary winding separated from each other.

Referring to FIG. 1, a substrate 2 is formed between a ferrite core 1 composed of an upper core and a lower core, and a metallic pattern layer 3 is wound on the substrate 2. The windings are plane windings.

The primary winding is composed of a primary winding 3-1 and a secondary winding 3-2. The primary winding 3-1 is connected to the primary winding terminal L1 and the secondary winding 3-2 Is connected to the secondary winding terminal L2.

The turn of the primary winding is 32 turns and the turn of the secondary winding is 4 turns. In this case, the primary winding is composed of four metal layers composed of eight turns in the layer, and the secondary winding is composed of two metal layers composed of two turns in the layer.

Thus, to place both the primary and secondary windings, six metal layers and five PCB dielectric layers are required. When the auxiliary winding is added, the number of stacks of the PCB substrate is further increased. Therefore, the manufacturing cost of the planar transformer increases, and the total transformer size becomes larger as the thickness of the PCB substrate layer becomes thicker.

Therefore, it is necessary to reduce the number of substrates stacked for miniaturization.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dual-core planar transformer that can be downsized by reducing the number of substrates.

According to an embodiment of the present invention, there is provided a dual core planar transformer comprising: a core portion having a pair of cores magnetically coupled to each other; And a substrate portion disposed between the pair of cores, the substrate portion including a plurality of substrates formed with first through holes and second through holes, wherein the substrate is provided with first and second through holes A primary winding and a secondary winding formed in a double helix structure can be formed.

In addition, in the dual core planar transformer according to an embodiment of the present invention, the substrate includes a first substrate and a second substrate on which the primary winding is formed; And a third substrate on which the secondary winding is formed.

Also, in a dual core planar transformer according to an embodiment of the present invention, the primary winding may be wound in the same ratio on the first substrate and the second substrate.

In addition, in the dual core planar transformer according to an embodiment of the present invention, the secondary winding may be wound at an unequal ratio to the first substrate and the second substrate.

In a dual core planar transformer according to an embodiment of the present invention, a first primary winding is formed on the first substrate, a second primary winding is formed on the second substrate, And the second primary winding may have opposite winding directions.

In addition, in the dual core planar transformer according to an embodiment of the present invention, the first primary winding and the second primary winding may be connected to the primary winding terminal through a via hole.

Further, in a dual core planar transformer according to an embodiment of the present invention, the secondary winding is connected to a winding terminal through a via hole.

According to the embodiment of the present invention, the energy efficiency is superior to that of a conventional planar transformer.

According to the embodiment of the present invention, it is possible to constitute a smaller number of substrates than a conventional planar transformer, and the thickness of the transformer can be reduced.

According to an embodiment of the present invention, it is lighter than a conventional planar transformer.

According to the embodiment of the present invention, the upper end face of the ferrite core can be made into a thin planar shape, thereby reducing the cost.

According to the embodiment of the present invention, the metal thickness of the secondary winding can be reduced by improving the efficiency due to the double spiral structure.

According to the embodiment of the present invention, the on-board system can be realized with fewer PCB stacking than the conventional planar transformer.

According to the embodiment of the present invention, the winding capacitance generated in the line pattern of the upper / lower layer due to the reduction of the stacked substrate can be reduced and the efficiency can be improved.

Figure 1 shows a transformer according to the prior art.
Figure 2 illustrates a dual core planar transformer in accordance with one embodiment of the present invention.
FIG. 3 is an enlarged view of FIG. 2 (b).
Fig. 4 is an enlarged view of Fig. 2 (c).
5 is an exploded perspective view of the dual core planar transformer according to an embodiment of the present invention.
Figure 6 compares a conventional planar transformer with a dual core planar transformer according to the present invention.
FIG. 7 shows a comparison of the magnetic flux density of a conventional planar transformer and a dual-core planar transformer according to the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the drawings, embodiments of the present invention are not limited to the specific forms shown and are exaggerated for clarity. Although specific terms are used herein, It is to be understood that the same is by way of illustration and example only and is not to be taken by way of limitation of the scope of the appended claims.

The expression " and / or " is used herein to mean including at least one of the elements listed before and after. Also, the expression " coupled / connected " is used to mean either directly connected to another component or indirectly connected through another component. The singular forms herein include plural forms unless the context clearly dictates otherwise. Also, as used herein, "comprising" or "comprising" means to refer to the presence or addition of one or more other components, steps, operations and elements.

Also, the expressions such as 'first, second', etc. are used only to distinguish between plural configurations, and do not limit the order or other features among the configurations.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under / under" Quot; includes all that is formed directly or through another layer. The criteria for top / bottom or bottom / bottom of each layer are described with reference to the drawings.

Hereinafter, a dual core planar transformer according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a perspective view illustrating a dual-core planar transformer according to an embodiment of the present invention. FIG. 2 (a) is a perspective view showing the entire planar transformer, FIG. (c) is a perspective view showing a state that the core portion 10 and the substrate portion 20 are removed, and FIG. 10 (d) shows the primary winding and the secondary winding separately.

FIG. 3 is an enlarged view of FIG. 2 (b), FIG. 4 is an enlarged view of FIG. 2 (c), and FIG. 5 is an exploded perspective view of the dual core planar transformer.

2 and 5, a planar transformer according to an embodiment of the present invention includes a core portion 10, a substrate portion 20, and a pattern portion 30.

The core portion 10 may be composed of a pair of ferrite cores 11 and 12 which are magnetically coupled to each other. That is, the upper core 11 and the lower core 12 are combined. The upper core 11 and the lower core 12 may have protrusions 13 and 14 protruded at both ends thereof and the protrusions 13 and 14 may have a rectangular shape.

The protrusions 13 and 14 pass through the through holes H1 and H2 formed in the base portion 20 and spiral windings are formed around the through holes H1 and H2. The protrusions 13 and 14 contact the upper core 11 to form a contact surface. Both edges of the lower core 12 can also be protruded, and contact with the upper substrate 11 forms a contact surface. That is, four contact surfaces are formed to contribute to the formation of the magnetic flux. The formation of the magnetic flux will be described later.

The substrate 20 may include a first substrate 21 to a third substrate 23. Each of the substrates 21, 22, and 23 may be sequentially stacked, and each substrate may have a first through hole H1 and a second through hole H2.

Each of the substrates may have a hole for connecting a winding terminal. That is, the primary winding terminal L1 of the base unit 20 can be connected, and the secondary winding terminal L2 can be connected to the other side.

A winding having a double helix structure may be formed around the through holes (L1, L2). That is, the pattern unit 30 may include a primary winding pattern (hereinafter referred to as a primary winding) and a secondary winding pattern (hereinafter referred to as a secondary winding).

The primary winding may be formed along the perimeter of the through hole formed in the substrate. One spiral 311 is formed around the first through hole H1 and another spiral 312 is formed around the second through hole H2 and these spirals are connected to each other through a connection 313 So that a single winding can be formed. The secondary winding also has a structure in which two spirals formed around the through holes H1 and H2 are connected together as in the case of the primary winding.

A via hole (v) may be formed in each substrate, and each of the windings is electrically connected to the winding terminal through the via hole. That is, the primary winding may be connected to the primary winding terminal L1 via the via hole, and the secondary winding may be connected to the secondary winding terminal L2 through the via hole. A plurality of via holes may be formed, a first one of the primary windings is connected through a first via hole, a second primary winding is connected through a second via hole, and the secondary winding is connected to a third via hole Lt; / RTI >

4, the primary winding includes a first primary winding 31 and a second primary winding 32. The first primary winding 31 and the second primary winding 32 are connected to each other, .

The first primary winding 31 is connected to the left side planar winding 312 and the right side planar winding 312 through a connection part 313. The second primary winding 32 is also connected to the left side planar winding and the right side planar winding through the connection portion 323. In this case, the first primary winding and the second primary winding may have opposite winding directions. This is because the connection portion 313 and the connection portion 323 intersect each other.

The secondary winding 33 is also the same as the primary winding, and the left and right side planar windings are connected to each other via the connecting portion 333. [ However, the secondary winding consists of one layer.

The primary winding 31 constitutes one spiral of the eight turns whereas the secondary winding 32 constitutes one spiral of the two turns of the plane winding so that the secondary winding 32 is connected to the primary winding The width of the winding can be wider than that of the coil.

By forming the primary winding and the secondary winding in a double spiral structure as described above, the number of boards can be reduced by half in comparison with a conventional planar transformer, and the total thickness of the transformer can be reduced.

Conventionally, in the primary winding, eight turn turns of the planar winding are formed into four layers to constitute 32 turns. In the present invention, however, eight turn turns form a single helix and two helices per layer So that 16 turns of plane windings can be formed in one layer. Therefore, it is possible to realize 32 turns with only two layers. That is, the number of turns of the primary winding is 32 turns, which is the same as the conventional one, but can be implemented with only two layers, so that the number of substrates can be reduced.

Similarly, the secondary winding is conventionally formed of two layers of two turns of plane windings, but in the present invention, it can be formed in one layer.

That is, by forming the core into a dual structure, conventionally, the five-layer PCB substrate layer can be reduced to three substrate layers.

6 illustrates a conventional planar transformer and a dual-core planar transformer according to the present invention. FIG. 6 (a) shows a conventional planar transformer, and FIG. 6 (b) shows a dual-core planar transformer according to the present invention .

Referring to FIG. 6, it can be seen that the thickness t1 of the conventional planar transformer is larger than the thickness t2 of the planar transformer according to the present invention.

Hereinafter, the operation of the dual core planar transformer according to the present invention will be described.

The double helical winding wire formed on the substrates 21, 22 and 23 closely contacts the upper core 11 of the core portion 10 and the protruding portions 13 and 14 of the lower core 12. The magnetic field generated in the primary winding is applied to the left protruding portion 13 of the lower core 12 and the right protruding portion 14 of the lower core 12 Since a closed loop is formed, a magnetic flux flows.

This magnetic flux is induced in the secondary winding and a magnetic field is generated. At this time, the current set by the winding ratio flows through the secondary winding terminal.

FIG. 7 shows a comparison of the magnetic flux density. FIG. 7 (a) shows the magnetic flux density of the planar transformer according to the prior art, and FIG. 7 (b) shows the magnetic flux density of the dual core planar transformer according to the present invention.

Referring to FIG. 7, a conventional planar transformer is provided with a single central protrusion of the upper / lower ferrite core. In addition, ferrite core contact surfaces are provided on both sides of the center portion to form three contact surfaces. At this time, a first magnetic flux 71 and a second magnetic flux 72 are formed to constitute the magnetic flux density of the planar transformer.

However, the dual-core planar transformer has two contact surfaces formed on both sides of the ferrite core and on both sides of the center protrusion so that four contact surfaces are formed. In this case, a magnetic flux 73 and a magnetic flux 74 are formed, and a magnetic flux, which is a main magnetic flux in a closed loop in which a first center contact surface and a second center contact surface are formed, 75 are formed to configure the magnetic flux density of the dual core planar transformer.

The magnetic flux density of a dual core planar transformer is higher than the flux density of a planar transformer, thereby transferring energy (power) more efficiently.

It can be seen that the dual core planar transformer is more energy efficient than the conventional planar transformer.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, the true scope of the present invention should be determined by the following claims.

10: core part
20:
30:
21 to 23: First to third substrates
31 ~ 32: Primary winding
33: Secondary winding
313, 323, 333:

Claims (7)

A core portion having a pair of cores magnetically coupled to each other; And
And a substrate portion disposed between the pair of cores, the substrate portion including a plurality of substrates formed with first through holes and second through holes,
Wherein the substrate has a primary winding and a secondary winding formed in a double helix structure around the first through holes and the second through holes.
The substrate processing apparatus according to claim 1,
A first substrate and a second substrate on which the primary winding is formed; And
And a third substrate on which the secondary winding is formed.
3. The method of claim 2,
Wherein the primary winding is wound in the same ratio on the first substrate and the second substrate.
3. The method of claim 2,
Wherein the primary winding is wound on the first substrate and the second substrate at a non-uniform rate.
3. The method of claim 2,
A first primary winding is formed on the first substrate,
A second primary winding is formed on the second substrate,
Wherein the first primary winding and the second primary winding have opposite winding directions to each other.
6. The method of claim 5,
Wherein the first primary winding and the second primary winding are connected to the primary winding terminal via a via hole.
3. The method of claim 2,
Wherein the secondary winding is connected to the secondary winding terminal via a via hole.

Images