WO2018008884A1

WO2018008884A1 - Double helical planar transformer

Info

Publication number: WO2018008884A1
Application number: PCT/KR2017/006770
Authority: WO
Inventors: 이주열
Original assignee: 이주열
Priority date: 2016-07-07
Filing date: 2017-06-27
Publication date: 2018-01-11
Also published as: KR20180005800A; KR101838223B1

Abstract

A double helical planar transformer according to one embodiment of the present invention can comprise: a core unit having a pair of cores electromagnetically coupled to each other; a substrate unit disposed between the pair of cores and comprising a plurality of substrates stacked on each other; and a pattern unit including a metal pattern of a double helical structure and formed on the substrates.

Description

【Specification】

[Name of invention]

Double spiral flat transformer

Technical Field

FIELD OF THE INVENTION The present invention relates to planar transformers and, more particularly, to double helical planar transformers.

Background Art

Planar transformers are used in a variety of applications such as flyback converters and Ethernet communications.

Wired Ethernet is increasing in speed with standards such as LOObased-T, 1000Based-T and LOGBased-T. The transmission cable of Ethernet has a differential resistance between the positive and negative ends of a cable in which a pair of cables cross each other (twisted pair, or twisted pair).

The structure of Ethernet cable can be divided into UTP Jnshi elded twisted pair and STP (Shi elded twisted pair).

1 is a basic equivalent model of an Ethernet transformer, and has a structure that separates a system from a line side. It passes the signal and removes only the noise to protect it from the noise of a twisted pair cable that is vulnerable to noise.

It is expressed as CMRR (Co 隱 on Mode Reject ion Rat io) and can be calculated as “C 匪 R = 20 log V2 / V1”.

FIG. 2 is a side-outer shape of a 100Based-T transformer using a common two-pair cable, each composed of an isolated transformer and a common mode choke per pair. In some cases, common mode choke may be omitted.

Here, the insulating transformer has a structure in which an enamel coated copper wire is wound around a ferrite i toroidal, and four enamel coated copper wires are manually wound at the same time. Two system-side copper terminations per pair are connected to TX + / RX + and TX- / RX-, and the remaining two ends of each pair are connected together to ground through a 100nF capacitor. One copper wire end per pair is pin 1/3 of connector (1),

Connected to pins 2/6, the remaining two ends of each pair are connected together and reconnected together through 75Ω each to ground through a 100nF capacitor.

3 shows the actual structure of the ferrite toroidal (2).

Due to the flux density of the ferrite toroidal due to the flow of the Ethernet signal, signal transmission occurs. In this toroidal structure, it is necessary to wind four copper wires (3) by hand, which is difficult because of the small size of the toroidal. In general, the diameter of the toroidal (2) is about 2.4-4.5 mm and the inner diameter is very small, 1.0 2.5 kPa. If the diameter of the toroidal is larger, it is possible to wind the copper wire by automation equipment. However, in general network equipment, since it is small, a manually produced transformer is used.

By manual labor, the mass production rate is slow, but the defect rate reaches 30%. In addition, the addition of a common mode choke (co 瞧 on mode choke) is a more complicated structure that is increasing the failure rate.

Figure 4 (a) shows a separate transformer, Figure 4 (b) shows a case in which the common mode choke is added.

4, it can be seen that the structure is complicated when the common mode choke is added.

Therefore, even in such a complicated structure, it is necessary to develop a structure of a transformer capable of improving the defect rate and automatically mass-producing.

Attempts have been made to break the manual process of winding copper wire in ferrite toroidals. Representatively "US8, 203, 418 B2" FR4 multilayer ferrite toroidal

It has the effect of winding the copper wire by using a lot of via holes as if it is inserted into the PCB and sewn, but it uses too many via holes, and many intersections of the tracks increase the price of the product. "IEEE Transactions on Power Electronics, Vol. 28, No. 9, pp. 4182-4201, Sept." is also implemented on semiconductor wafers. Alternatively, wind the enamelled copper wire around a ferrite bobbin as shown in TDK application note, "The New Reference LAN Pulse Transformer," and then use the ferrite cover to cl osed l oop method for forming magnetic flux density. Similarly, there is a method such as "10-2006-7020659 / 10-2009-7004433 / 10-2013-7024946" which implements a binary inductor coil on a semiconductor wafer, but similarly, a structure in which many intersections and via holes occur. "Electronics Packaging

Manufacturing, IEEE Transactions, vol. 23, pp. In 48-55, the rectangular ferrite layer is implemented on the wafer to form a pattern around the top and bottom. Similarly, many via holes and intersections occur. Patent "US 7, 915, 992 B2, CN, which mentions a double helix winding or" 8 "shaped winding, although with a different application.

1674173A, CN 102403096 "s ingle-ended windings connected by a single line and can be applied to differential winding structures in which CMRR Co 隱 on Mode Rej ect i on Rat io, such as Ethernet transformers, are of importance. none.

[Detailed Description of the Invention]

[Technical problem]

The problem to be solved by the present invention is a double spiral plane capable of mass production To provide a transformer. Technical Solution

A dual helical planar transformer according to an embodiment of the present invention includes a core part having a pair of cores electromagnetically coupled to each other; A substrate portion comprising a plurality of substrates disposed between the pair of cores and stacked on each other; And a pattern portion including a metal pattern of a binary spiral structure formed on the substrate.

In addition, in the double helical planar transformer according to an embodiment of the present invention, the substrate portion includes a first through hole and a second through hole, and the metal pattern includes a first spiral and the first spiral hole formed in an area around the first through hole. And a second helix formed in a region around a second through hole, wherein the first helix and the second helix are integrally connected to form a double helix.

In addition, in a double-sided spiral planar transformer according to an embodiment of the present invention, the substrate portion may include a first substrate, a second substrate, a third substrate, a fourth substrate, and a fifth substrate sequentially stacked with a plurality of via holes. A first double helix is formed on the first substrate, a second double helix is formed on the second substrate, a third double helix is formed on the third substrate, and a fourth double helix is formed on the fourth substrate. And a connecting terminal and a ground terminal connected to the first double helix to the fourth double helix and the via hole in the crab 5 substrate, and the connecting terminal is formed in an area around the first through hole. The ground terminal may be formed in an area around the second through hole.

In addition, in a double helical planar transformer according to an embodiment of the present invention, the connection terminal includes Τχ +, Τχ—, Rx +, Rx- terminals, and the first double helix is connected to the Tx + terminal through a first via hole. The second double helix is connected to the Τχ-terminal through a second via hole, the third double helix is connected to the Rx + terminal through a giant 13 via hole, and the fourth double helix is connected to the fourth via hole. It can be connected to the Rx terminal.

In addition, in the double helical planar transformer according to an embodiment of the present invention, the first double helix to the fourth double helix may be formed in a counterclockwise direction.

Further, in a double-sided spiral flat transformer according to an embodiment of the present invention, the first double helix is formed counterclockwise, the second double helix is formed clockwise, and the third double helix is clockwise. The fourth double helix may be formed in a counterclockwise direction.

Further, in the double helical planar transformer according to an embodiment of the present invention, the first double helix is formed in a clockwise direction, the second double helix is formed in a counterclockwise direction, and the third double helix is formed in a clockwise direction. The fourth double helix may be formed in a counterclockwise direction.

Further, in a double-sided spiral flat transformer according to an embodiment of the present invention, the first double helix is formed in a clockwise direction, the second double helix is formed in a clockwise direction, and the third double helix is made in a counterclockwise direction. Formed, the fourth double helix It may be formed counterclockwise.

In addition, in the double helical planar transformer according to an embodiment of the present invention, the ground terminal includes a first ground terminal and a second ground terminal, the giant U double helix and the second double helix is the first ground terminal The third double helix and the fourth double helix may be connected through a fraudulent second ground terminal.

【Effects of the Invention】

According to an embodiment of the present invention, the manual winding of the toroidal embedded in the Ethernet transformer can be automated.

In addition, according to the present invention, it is possible to improve the defective rate of the Ethernet transformer due to the manual winding of the toroidal.

In addition, according to the present invention, since it is composed only of the pattern of the PCB, the yield is excellent.

In addition, according to the present invention, because the PCB design technique is used, the performance is superior to the conventional Ethernet transformer.

In addition, according to the present invention, it is possible to mass-produce due to a simple manufacturing process compared to the existing planar Ethernet transformer, and mass production is excellent.

In addition, the present invention has fewer PCB via holes and fewer line pattern intersections than conventional planar Ethernet transformers.

In addition, according to the present invention, since no closed loop ferrite such as toroidal is used, mass productivity is excellent.

In addition, according to the present invention, the performance of the transformer is superior to the conventional s ingle-ended double helix winding or "8-shaped" winding.

In addition, according to the present invention, it is possible to miniaturize smaller according to the effective dielectric constant characteristics of the PCB, it can be applied to the semiconductor process.

[Brief Description of Drawings]

1 shows an equivalent model of an Ethernet transformer according to the prior art. 2 shows a circuit diagram of a 100 Base T Ethernet transformer according to the prior art.

Figure 3 shows the structure of a ferrite toroidal in a conventional Ethernet transformer.

4 shows a ferrite toroidal structure to which common mode chokes have been added. Figure 5 shows a rectangular toroidal structure for explaining the present invention. 6 is an exploded perspective view of a double helical transformer according to an embodiment of the present invention.

7 is a view illustrating a shape in which a substrate is removed from a double helical planar transformer according to an exemplary embodiment of the present invention. 8 to 11 show various embodiments of various winding methods.

12 shows the magnetic flux density of a planar transformer having a double helix structure. Figure 13 shows the magnetic field distribution of a planar transformer of a double helix structure. FIG. 14 shows the effective permeability distribution for the ferrite cores of a double helical planar transformer.

[Best form for implementation of the invention]

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In the drawings, the embodiments of the present invention are not limited to the specific forms shown, and are exaggerated for clarity. Although specific terms have been used herein, they are used for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or the claims.

The expression 'and / or' is used herein to mean at least one of the components listed before and after. In addition, the expression 'connected / coupled' is used to mean that it is connected directly to other components or indirectly through other components. As used herein, the singular forms "a", "an" and "the" include plural unless the context clearly dictates otherwise.

Components, steps, operations and elements referred to as 'comprising' means the presence or addition of one or more other components, steps, operations and elements.

Also, expressions such as 'first' and 'second' are used only for distinguishing a plurality of components, and do not limit the order or other features between the components.

In the description of the embodiments, each layer (region), region, pattern or structures may be "under" or "under" the substrate, each layer (film), region, pad or pattern. "Formed in" includes both those formed directly (di rect ly) or through other layers. The criteria for up / down or down / down of each layer will be described with reference to the drawings. Hereinafter, with reference to the accompanying drawings will be described in detail the double spiral planar transformer and the determination method according to an embodiment of the present invention.

Figure 5 shows a rectangular toroidal structure for implementing a double helical planar transformer.

Referring to Figure 5, the conventional toroidal is deformed in the form of a fire You can see that.

If the windings are evenly gathered, a double spiral or "8" shape can be seen. All double helixes are basic toroidal structures.

However, there have been no cases where the differential helix structure is implemented as a differential structure and there is no case applied to the Ethernet transformer.

6 is an exploded perspective view of a double helical planar transformer according to an exemplary embodiment of the present invention, and implements a rectangular ferrite structure as shown in FIG. 6 in a planar form.

7 illustrates a shape in which a substrate is removed from a double helical planar transformer according to the present invention, and FIGS. 8 to 11 illustrate various winding methods.

6 and 7, 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 electromagnetically coupled to each other. That is, the upper core 11 and the lower core 12 are combined. Each of the upper core 11 and the lower core 12 has protrusions 13 and 14 protruding from both ends thereof, and the protrusions 13 and 14 may have a circular shape.

The protrusions 13 and 14 penetrate through the through holes HI and H2 formed in the substrate 20, respectively, and a spiral pattern is formed around the through holes HI and H2.

The substrate unit 20 may include a first substrate 21 to a fifth substrate 25. Each of the substrates 21, 22, 23, 24, and 25 may be sequentially stacked, and each of the substrates may include a first through hole HI and a second through hole H2.

A plurality of via holes may be formed in a region around the through holes formed in each of the substrates.

First to fourth via holes (vl, v2, v3, and v4) are formed around the U through hole, and crab 5 to 8 via holes (v5, v6, v7, and v8) are formed around the second through hole. Can be. The substrate portion 20 is rectangular in shape and long in one direction, and a plurality of grooves may be formed at the edge of the rectangular length.

Each of the substrates may have a double spiral pattern formed around the through hole. That is, the pattern portion 30 includes the first pattern 31 to the fourth pattern 34, and each pattern is formed in a double spiral structure on the first substrate 21 to the fourth substrate 24. Can be. Each pattern may be a metal pattern.

In addition, connecting terminals 251, 252, 253, 254 and ground terminals 255, 256, which are connected to the respective patterns 31, 32, 33, and 34, are formed on the substrate 5. Solder masks 257 are formed in regions other than the formed portions to protect the circuits.

Reference numeral 251 may be a Tx + terminal of the transmitting end, and reference numeral 252 may be a Τχ- terminal of the transmitting end.

Reference numeral 253 may be an Rx + terminal of the receiving end, and reference numeral 254 may be an Rx- terminal of the receiving end. Reference numeral 255 may be a ground terminal (Tx GND) of the transmitter, and reference numeral 256 may be a ground terminal (Rx GND) of the receiver.

Referring to the pattern structure again, the first pattern 31 may be formed in the first substrate 21 and connected to the Tx + terminal 251 through the first via hole vl.

The second pattern 32 may be formed in the second substrate 22 and may be connected to the Tx terminal 252 through the second via hole ν2.

The third pattern 33 may be formed on the third substrate 23 and may be connected to the Rx + terminal 253 through the third via hole v3.

The fourth pattern 34 may be formed in the fourth substrate 24 and connected to the Rx terminal 254 through the fourth via hole _v 4.

That is, the first pattern 31 is a Tx + double helix winding, the second pattern 32 is a Tx− double helix winding, the third pattern 33 is an Rx + double helix winding, and the fourth pattern 34 is Rx -Can be a double helix winding. That is, according to the structure as described above, the Tx + double helix winding 31 formed on the first substrate 21 and the Tx- double spiral winding 32 formed on the second substrate 22 are formed by the fifth, six via holes v5, v5) and Tx ground terminal (255).

The Rx + dual helix winding 34 formed on the fourth substrate 24 and the Rx double helix winding 35 formed on the fifth substrate 25 connect the seventh, eight via holes 07, v8 and the Rx ground terminal 256. Connected through.

Each transmitting end and receiving end winding is combined with the upper and lower ends of the ferrite core to form a magnetic flux density to transmit signals. That is, when the Ethernet differential signal is applied to the Tx + and Tx- terminals, the magnetic field due to the Tx winding current generates a magnetic field by the magnetic flux density of the ferrite core and receives the Ethernet signal by flowing a current through the Rx winding. At this time, since the noise signal induced by Tx + and Tx- is in phase, the signal exits to ground through the Tx ground terminal and cancels out. At this time, the upper and lower ferrite core should be in close contact with each other.

Each pattern constituting the pattern portion 30 is a double helix structure, but it appears that there are two patterns, but one pattern is connected. This can be easily confirmed with reference to FIG. 7.

Referring to FIG. 7, the pattern 30 surrounds both edges of the ferrite core part 10 in a double spiral structure, and the patterns are connected to one. Such a structure can realize a planar transformer of a binary helical structure having a minimum intersection point (X).

Both ends of the pattern of FIGS. 7 to 11 are different from the terminals 251, 252, 253, 254, 255, and 256 formed on the first substrate 21, but both ends of the pattern are the terminals. Since the same reference numerals are used.

8 to 11, FIG. 8 is an embodiment of a double-helical planar transformer having a minimum intersection point, in which both Tx + and Tx- of the transmitting end are windings in a counterclockwise direction and TX Are connected to each other at GND. Also, Rx + and Rx 'at the receiving end are also counterclockwise windings and are connected to each other at RX GND.

9 is another embodiment of a double helix planar transformer having a minimum cross point, where Tx + of the transmitting end is a counterclockwise direction, Τχ— is a clockwise winding and is connected to each other at TX GND. Also, Rx + in the receiver is clockwise, Rx- is the counterclockwise winding and connected to each other at RX GND.

10 is another embodiment of a double helix planar transformer having a minimum cross point, where Tx + of the transmitter is clockwise and Τχ- is a winding in a counterclockwise direction and is connected to each other at TX GND. Also, Rx + at the receiving end is clockwise and Rx- is the counterclockwise winding and is connected to each other at RX GND.

11 is another embodiment of a double helix planar transformer with a minimum cross point, where Tx + of the transmit end is clockwise and Τχ- is a winding in the clockwise direction and connected to each other at TX GND. In addition, Rx + at the receiving end is counterclockwise, Rx- is the counterclockwise winding and connected at RX GND.

12 to 14 show simulation results of a double helical transformer according to an embodiment of the present invention, FIG. 12 shows the magnetic flux density of a planar transformer of a double helix structure, and FIG. 13 shows a magnetic field of a planar transformer of a double helix structure. FIG. 14 shows the effective permeability distribution for the ferrite core of the double-helix planar transformer.

12 and 13, ferrite cores are densely packed with arrows corresponding to magnetic fluxes and magnetic fields, and thus, the ferrite cores work well.

In FIG. 14, the higher the red color, the higher the permeability. Although embodiments according to the present invention have been described above, these are merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments of the present invention are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the following claims.

Claims

[Claim]

[Claim 1]

A core part having a pair of cores electromagnetically coupled to each other;

A substrate portion comprising a plurality of substrates disposed between the pair of cores and stacked on each other; A double helical planar transformer comprising a pattern portion including a metal pattern of a double helix structure formed on the substrate.

[Claim 2]

The method of claim 1,

The substrate portion includes a first through hole and a second through hole,

The metal pattern includes a first helix formed in an area around the first through hole and a second helix formed in an area around the second through hole, and the first helix and the second helix are integrally connected to form a double helix. Double spiral flat transformer.

[Claim 3]

The method of claim 2,

The substrate part may include a first substrate, a second substrate, a third substrate, a fourth substrate, and a fifth substrate on which a plurality of via holes are formed, sequentially stacked.

A first binary helix is formed on the first substrate

Two double helixes are formed on the second substrate.

A third triple helix is formed on the third substrate,

A fourth double helix is formed on the fourth substrate,

The crab 5 substrate is formed with a connection terminal and a ground terminal connected to the first double helix through the fourth double helix and the via hole,

The connection terminal is formed in a region around the first through hole, the ground terminal is a double helical planar transformer formed in the region around the second through hole.

[Claim 4]

The method of claim 3, wherein

The connection terminal includes a Τχ +, Τχ-, Rx +, Rx- terminal,

The first double helix is connected to the Tx + terminal through a first via hole, the second double helix is connected to the Τχ- terminal through a second via hole, and the third double helix is connected to the Rx + through a third via hole. A double helical planar transformer connected to the terminal and the fourth double helix connected to the Rx terminal through a fourth via hole.

[Claim 5]

The method of claim 3, Wherein the first to fourth double helixes are formed in a counterclockwise direction.

[Claim 6]

Tax in Clause 3

The first double helix is formed in a counterclockwise direction;

The second double helix is formed in a clockwise direction;

The third double helix is formed in a clockwise direction,

Wherein said fourth double helix is formed counterclockwise.

[Claim 7]

The method of claim 3,

The first double helix is formed in a clockwise direction;

The second double helix is formed counterclockwise;

The third double helix is formed clockwise;

The double helix is a double spiral planar transformer formed in the counterclockwise direction.

[Claim 8]

The method of claim 3,

The first double helix is formed in a clockwise direction;

The second double helix is formed in a clockwise direction;

The third double helix is formed counterclockwise;

Wherein said fourth double helix is formed counterclockwise.

[Claim 9]

The method of claim 3,

The ground terminal includes a first ground terminal and a second ground terminal,

Wherein the first double helix and the second double helix are connected through the first ground terminal, and the third double helix and the fourth double helix are connected via a second ground terminal.