KR101838227B1

KR101838227B1 - Common winding wire planar transformer

Info

Publication number: KR101838227B1
Application number: KR1020160089407A
Authority: KR
Inventors: 이주열
Original assignee: 이주열
Priority date: 2016-07-14
Filing date: 2016-07-14
Publication date: 2018-03-13
Also published as: KR20180007888A; WO2018012760A1

Abstract

A common winding plane transformer according to an embodiment of the present invention includes a core portion having a pair of cores magnetically coupled to each other; A substrate disposed between the pair of cores, the substrate having a first through hole and a second through hole; A first metal layer formed on a lower surface of the substrate to form a primary winding; And a second metal layer formed on the upper surface of the substrate to form a secondary winding and a secondary winding.

Description

{COMMON WINDING WIRE PLANAR TRANSFORMER}

FIELD OF THE INVENTION The present invention relates to planar transformers, and more particularly to a common winding plane transformer.

Although the miniaturization of the transformer is made possible by increasing the switching frequency, the loss is increased due to the reduction of the heat dissipation area due to the miniaturization. The 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 8 turns per layer, and the secondary winding is composed of two metal layers composed of two turns of 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 common winding plane transformer that can be downsized by reducing the number of substrates.

A common winding plane transformer according to an embodiment of the present invention is characterized in that at least one of the upper core and the lower core has two protrusions surrounded by a primary winding and a secondary winding of the transformer, A core portion formed by bonding; And a substrate having a first through hole and a second through hole through which the two protrusions penetrate, wherein a lower surface of the substrate is provided with a primary winding pattern having a double helix along the first through hole and around the second through hole, And a second metal layer, which is a secondary winding and an auxiliary winding pattern layer, is formed on the upper surface of the substrate along the first through holes and around the second through holes, Has a configuration in which two helical patterns having spools surrounding the respective projections at least twice are connected to each other on the substrate.

Also, in the common winding plane transformer according to an embodiment of the present invention, the secondary winding and the auxiliary winding may be disposed close to each other at regular intervals on the same plane.

Further, in the common winding plane transformer according to an embodiment of the present invention, the secondary winding and the auxiliary winding may be alternately arranged.

Also, in the common winding plane transformer according to an embodiment of the present invention, the first metal layer further includes a primary winding terminal connected to the primary winding, and the second metal layer is connected to the secondary winding to form a second winding A secondary winding terminal connected to the secondary winding and the secondary winding terminal may be further formed.

Further, in a common winding plane transformer according to an embodiment of the present invention, the primary winding is connected to the primary winding terminal through a first connecting line, and the secondary winding is connected to the secondary winding terminal And the auxiliary winding may be connected to the auxiliary winding terminal through a third connection line.

delete

Further, in the common winding plane transformer according to an embodiment of the present invention, the secondary winding and the auxiliary winding may have the same turns ratio.

delete

The secondary windings and the auxiliary windings may have different winding widths.

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 number of layers of the substrate and the thickness of the metal layer can be reduced by arranging the secondary winding and the auxiliary winding in the same layer.

According to the embodiment of the present invention, it is possible to arrange the secondary winding and the auxiliary winding in the same layer so that magnetic coupling can be smoothly performed with respect to the primary winding.

According to the embodiment of the present invention, the double-sided board can be used together with the primary winding by arranging the secondary winding and the auxiliary winding in the same layer.

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

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 common winding plane transformer in accordance with an 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 common winding plane transformer in accordance with one embodiment of the present invention.
6 compares a conventional planar transformer with a common winding plane transformer according to the present invention.
FIG. 7 shows a comparison of the magnetic flux density of a conventional plane transformer and a common winding plane 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 common winding plane 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 of a planar transformer as a whole, and FIG. 2 (b) is a perspective view showing a state in which the upper core 11 is removed. FIG. (c) is a perspective view showing a state in which the core portion 10 and the substrate 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 common winding plane transformer.

Referring to FIGS. 2 and 5, a planar transformer according to an embodiment of the present invention includes a core portion 10, a substrate 20, and a metal layer 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 substrate 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 ends of the lower core 12 can also be protruded, and contact with the upper core 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 is a double-sided substrate, and a metal layer 30 may be formed on the lower surface and the upper surface of the substrate, respectively. The substrate may have a first through hole H1 and a second through hole H2.

The metal layer 30 may include a first metal layer 31 formed on the lower surface of the substrate 20 and a second metal layer 32 formed on the upper surface of the substrate.

The first metal layer 31 may form a primary winding 310 and the second metal layer 32 may form a secondary winding 320 and an auxiliary winding 330.

The first metal layer 31 may further include a primary winding terminal L1 connected to the primary winding 310 and the second metal layer 32 may be electrically connected to the secondary winding 320. [ A secondary winding terminal L2 connected to the auxiliary winding 330 and an auxiliary winding terminal L3 electrically connected to the auxiliary winding 330 can be further formed.

The primary winding 310 and the primary winding terminal L1 are connected to each other through a first connecting line 41. The secondary winding 320 and the secondary winding terminal L2 are connected to a second connecting line 42, And the auxiliary winding 330 and the auxiliary winding terminal L3 may be connected through the third connecting line 43. [

Each of the winding terminals L1, L2 and L3 is constituted by a + terminal and a terminal, and the connecting lines 41, 42 and 43 are constituted by a + terminal connecting line and a - terminal connecting line, have.

The primary winding 310, the secondary winding 320 and the auxiliary winding 330 may have a double helix winding around the through holes H1 and H2.

At this time, the secondary winding 320 and the auxiliary winding 330 may be arranged at regular intervals on the same plane. That is, the secondary winding and the auxiliary winding are constituted by a common winding method and are alternately arranged to form a double helix.

Therefore, the number of windings of the secondary winding 320 and the auxiliary winding 330 is the same. However, the widths of the windings may be different from each other. In this embodiment, the width of the secondary winding 320 is formed wider than the width of the auxiliary winding 330.

The primary winding 310 has one spiral 311 formed around the first through hole H1 and one spiral 312 formed around the second through hole H2, The spirals can be connected to each other through the connection part 313 to form one winding.

The secondary winding 320 also has a single helix 321 along the first through hole H1 and a single helix 322 along the second through hole H2. And these spirals can be connected to each other through the connecting portion 323 to form a single winding.

Likewise, the auxiliary winding 330 has one spiral 331 formed around the first through hole H1 and another spiral 332 formed around the second through hole H2. The spirals can be connected to each other through the connecting portion 333 to form one winding.

The windings of the windings can be variously set according to the output voltage of the transformer. In one embodiment, the primary winding 310 may be 40 turns and the secondary winding 320 and the auxiliary winding 330 may be 4 turns.

As described above, by forming the windings in a double spiral structure, the number of substrates can be reduced by half in comparison with a conventional planar transformer, and the thickness can be further reduced by forming the secondary windings and the auxiliary windings on the same plane.

Conventionally, in order to form 40 turns on the primary winding, a flat winding of eight turns requires five layers of metal layers, and accordingly, the number of the substrates increases, so that the total thickness of the transformer is inevitably thick.

However, in the present invention, it is possible to achieve the same effect as the conventional one using only one layer of the substrate by forming the winding wire with a double helix and using the secondary winding and the auxiliary winding as a common winding.

6 shows a conventional planar transformer and a common winding plane transformer according to the present invention. FIG. 6 (a) shows a conventional planar transformer, and FIG. 6 (b) shows a common winding plane 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 common winding plane transformer according to the present invention will be described.

The double helical winding wire formed on the substrate 20 closely contacts the upper core 11 of the core portion 10 and the protrusions 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 magnetic flux densities. 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 common winding plane 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: substrate
30: metal layer
31: First metal layer
32: second metal layer
310: primary winding
320: Secondary winding
330: Secondary winding
41, 42, 43: connection line

Claims

A core portion having at least one of an upper core and a lower core formed with two protrusions which are surrounded by a primary winding and a secondary winding of a transformer and which are formed by the combination of the upper core and the lower core;
A substrate having a first through hole and a second through hole through which the two protrusions pass;
/ RTI >
Wherein a first metal layer, which is a primary winding pattern layer of a double helix, is formed on the lower end surface of the substrate along the first through holes and the second through holes,
A second metal layer, which is a secondary winding of a double helix and an auxiliary winding pattern layer, is formed on an upper surface of the substrate along a circumference of the first through hole and a second through hole,
Wherein the auxiliary windings are arranged at regular intervals along the shape of the secondary windings,
Wherein the double helix is connected to two spiral patterns on the substrate, each spiral pattern having a winding around at least two turns around each of the protrusions.

delete

The method according to claim 1,
Wherein the secondary winding and the auxiliary winding are alternately arranged in the same plane.

The method according to claim 1,
Wherein the first metal layer further includes a primary winding terminal connected to the primary winding,
Wherein the second metal layer further comprises an auxiliary winding terminal connected to the secondary winding and connected to the secondary winding terminal and the auxiliary winding.

delete

5. The method of claim 4,
The primary winding is connected to the primary winding terminal through a first connection line,
The secondary winding is connected to the secondary winding terminal through a second connection line,
And the auxiliary winding is connected to the auxiliary winding terminal through a third connecting line.

The method according to claim 1,
Wherein the secondary winding and the auxiliary winding have the same turns ratio.

The method according to claim 1,
Wherein the secondary winding and the auxiliary winding have different winding widths from each other.