JP2003086428A - Pulse transformer - Google Patents

Abstract

To provide a pulse transformer having a good longitudinal current balance. SOLUTION: A first primary winding P1 connecting between a first terminal 1 and a second terminal 2, and a second primary connecting between a third terminal 3 and a fourth terminal 4. Side winding P2 and fifth terminal 5
A first secondary winding S1 connecting between the first terminal 6 and the sixth terminal 6;
A second secondary winding S <b> 2 connecting the seventh terminal 7 and the eighth terminal 8 is provided. The secondary windings S1 and S2 are wound by an even layer so that the winding start end and the winding end end are close to the same flange 12 by bi-directional winding, and the first primary winding P1 and the second primary winding are wound. Each winding start end and winding end end of the winding P2 are wound so as to be close to the same flange 12, and the second primary winding is wound with respect to the winding direction of the first primary winding P1. The winding turning direction of the line P2 is the reverse direction.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, ADS.
The present invention relates to a pulse transformer applicable to L (Asymmetrical Digital Subscriber Line) and the like.

[0002]

2. Description of the Related Art As shown in FIG. 7, in an ADSL, a pulse transformer PT1 is arranged in parallel with a circuit formed by a capacitor C1 and a coil L1 for passing a bell signal of 16 Hz to a general telephone line 101. A device or the like is connected. In addition, general telephone line 101
On the other hand, an insulating pulse transformer PT2 is connected via a capacitor C2, and a data communication transmitting / receiving circuit is connected to this pulse transformer PT2.

In the above, the pulse transformer PT2 transmits a signal having a frequency higher than the voice frequency band to the general telephone line 101.
It is provided to perform data communication by superimposing it on, and the frequency handled is 30 KHz or more. Thus, since the frequency band of data communication is outside the main band of the general telephone line 101, the transmission loss is large and the level of the signal handled is low.

In the pulse transformer PT2,
Longitudinal Balance characteristics are required. Here, the vertical currents are the currents Ia and Ib that flow in the same direction in the balanced two-conductor wire that uses the ground as a return path by using each electric wire of the general telephone line 101 as shown in FIG.

As shown in FIG. 8, a general telephone line 101
Is a balanced line that extends around the air and extends to homes and the like, so that unnecessary broadcast radio waves N1 and city noise N2 may be superimposed on the pair wires in common mode.

[0006]

Therefore, in the pulse transformer PT2 used on the above-mentioned data communication side,
When the vertical current balance is poor, the pulse transformer PT2
The undesired wave component of the common mode appears on the secondary side of, and causes deterioration of data communication quality.

On the other hand, in the pulse transformer PT1, the frequency to be handled is as low as 0.3 to 3.4 KHz, and the influence of noise superimposed in the common mode is not great. Further, the frequency range is the main band, the signal level handled is large, and the accuracy of the pulse transformer PT2 is not required.

The problem in the pulse transformer PT2 will be described in detail. As shown in FIG. 9, if a common-mode signal SIG is generated between the two wires on the input side with the ground, currents I1 and I2 flow in the primary coil, and a solid line is drawn by the first primary coil P1. And a magnetic flux F1 indicated by a broken line is generated by the second primary side coil P2.
2 occurs. Here, the first primary coil P1 and the second primary coil P1
If there is any difference in the primary coil P2 (DCR (resistance value when a direct current is applied), number of turns, stray (stray capacitance between windings), degree of coupling with the secondary coil S, etc.) , A difference occurs between the magnetic fluxes F1 and F2.

If there is no difference between the magnetic fluxes F1 and F2, the directions are opposite to each other and cancel each other, but if there is a difference, an induced voltage is generated in the secondary coil S according to the difference.
In this case, the higher the frequency is, the more common mode signal S
IG is likely to occur and it is difficult to balance.

Conventionally, a pulse transformer PT2 as shown in FIG.
In order to sufficiently secure the coupling between the primary side and the secondary side, the first secondary winding S1 and the second secondary winding S2 are bifara windings and balanced. The first secondary side winding S1 and the second secondary side winding S1 wound by the above bi-fara
2 is sandwiched between the first primary winding P1 and the second primary winding P1. FIG. 10 shows a cross-sectional view of one side of the bobbin 100. The actual bobbin 100 and the windings P1, P2, S1 and S2 are 3 with the center line shown in the figure as the center.
It has been rotated by 60 degrees.

The arrow in FIG. 10 indicates the winding advance direction of the winding. Then, the first primary winding P1 is wound around the shaft 103 from the fourth terminal 4 side close to the first flange 101 to the third terminal 3 side close to the second flange 102, The secondary winding P2 of 2 is the first flange 10
From the second terminal 2 side close to 1 to the second flange 102
Is wound up toward the side of the first terminal 1 which is close to. Also,
A fifth secondary side winding S1 and a second secondary side winding S2 are formed by a bi-fara winding so as to be close to the second flange 102.
From the side of the terminal 5 and the side of the seventh terminal 7 to the side of the sixth terminal 6 and the side of the eighth terminal 8 which are close to the second flange 102.

Therefore, when the first primary winding P1 and the second primary winding P2 are compared, the corresponding terminals, that is, the first terminal 1 and the fourth terminal 4 are located at the first position. The secondary side winding S1 and the second secondary side winding S2 are arranged under different electrical and magnetic conditions, and the positions of the corresponding second terminal 2 and third terminal 3 are also The first secondary winding S1 and the second secondary winding S2 are arranged under different electrical and magnetic conditions. In other words, the arrangement was not such that vertical current balance could be achieved.

The present invention has been made in view of the above circumstances, and an object thereof is to improve vertical current balance and reduce leakage inductance in a pulse transformer used on the circuit side of data communication in ADSL, for example.
In other words, it is to provide a product having a good degree of coupling.

[0014]

A pulse transformer according to claim 1 of the present invention comprises a first primary side winding connecting a first terminal which is not grounded and a second terminal which is grounded, and a ground. A second primary winding that connects between a third terminal that is grounded and a fourth terminal that is not grounded, and a first second wire that connects between a fifth terminal that is not grounded and a sixth terminal that is grounded. A secondary winding, and a second secondary winding connecting between a grounded seventh terminal and an ungrounded eighth terminal, each winding comprising a first and a second flange. In a pulse transformer wound around the bobbin, the first and second secondary windings are wound by even-numbered layers by bi-fara winding so that the winding start end and the winding end end are close to the same flange. The winding start ends of the first primary winding and the second primary winding are close to the same flange. And the first primary side winding and the second primary side winding are wound so that respective winding end ends of the first primary side winding and the second primary side winding are close to the same flange. The winding turning direction of the second primary side winding is opposite to the winding turning direction.

In a pulse transformer according to a second aspect of the present invention, the first and second secondary windings are sandwiched by the first primary winding and the second primary winding. Wound so as to be laminated in a state, between the first and second secondary windings and the first primary winding, and between the first and second secondary windings and The insulating tape having a required number of turns is wound between the second primary winding and the second primary winding, respectively.

A pulse transformer according to a third aspect of the present invention is a first and second primary side windings connected in parallel so as to connect a first terminal which is not grounded and a second terminal which is grounded. A third and fourth primary windings connected in parallel so as to connect between a grounded third terminal and a non-grounded fourth terminal, and a fifth grounded terminal and a fifth grounded terminal. 6
And a second secondary winding connected between the second terminal and a seventh terminal that is grounded and an eighth terminal that is not grounded. In a pulse transformer in which each winding is wound around a bobbin having first and second flanges, the first and second secondary windings are bi-fara winding, and the winding start end and the winding end end have the same flange. The first and third primary side windings are wound by even-numbered layers so that the winding start end and the winding end end are close to the same flange by the bi-fara winding.
And the fourth primary side winding is wound by biphasic winding so that the winding start end and the winding end end are close to the same flange, and the first and third primary side windings are wound in the turning direction. On the other hand, the winding directions of the second and fourth primary side windings are opposite to each other.

In a pulse transformer according to a fourth aspect of the present invention, the first and second secondary windings are the first and third primary windings and the second and fourth primary windings. It is wound so as to be laminated while being sandwiched by windings, and is wound between the first and second secondary windings and the first and third primary windings, and the first and second windings. It is characterized in that an insulating tape having a required number of turns is wound between each of the two secondary windings and the second and fourth primary windings.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a pulse transformer according to the present invention will be described below with reference to the accompanying drawings. In each of the drawings, the same constituents are designated by the same reference numerals, and overlapping description will be omitted. Each pulse transformer according to the present invention is also provided at the position of the pulse transformer PT2 shown in FIG.

The pulse transformer according to the first embodiment shown in FIG. 1 has a circuit configuration as shown in FIG. In other words, this pulse transformer is the first
Of the first primary winding P2 connecting between the terminal 1 of the above and the second terminal 2 which is grounded, and the second connecting between the third terminal 3 which is grounded and the fourth terminal 4 which is not grounded Primary winding P1
And a first secondary winding S1 connecting between a fifth terminal 5 which is not grounded and a sixth terminal 6 which is grounded, a seventh terminal 7 which is grounded and an eighth terminal 8 which is not grounded And a second secondary winding S2 that connects between and. Note that, in FIG. 2, black circle marks represent the polarities of the windings.

The windings P1, P2, S1 and S2 are
It is wound on a bobbin 10 having a first flange 11 and a second flange 12 shown in FIG. FIG. 1 is a cross-sectional view of one side of the bobbin 10, showing the actual bobbin 1
0 and each of the windings P1, P2, S1 and S2 are in a state of being rotated 360 degrees about the illustrated center line. Also,
The arrow indicates the winding direction of the winding.

A first primary winding P1 is wound around the shaft 13 of the bobbin 10, and the terminal 4 is located close to the first flange 11.
The side is the winding start end, and the side of the terminal 3 close to the second flange 12 is the winding end end. Here, the first primary winding P1 is wound in only one layer, but the number of layers is not particularly limited.

On the upper layer of the primary winding P1, the first secondary winding S1 and the second secondary winding S2 are bi-fara winding, and the winding start end and the winding end end have the same flange. Even number layers (two layers in the present embodiment) are wound so as to be close to (here, the second flange 12). Here, bi-fara winding means that two paired wires are aligned and wound.

The first secondary winding S wound in a bi-fara manner
In the upper layers of the first and second secondary windings S2, the same flange (here, the first flange 11) side as the winding start end of the first primary winding P1 is set as the winding start end, and The same flange (here, the second flange 12) side as the winding end of the primary winding P1 is set as the winding end, and the second primary winding P
2 is wound by the same number of layers as the first primary winding P1.

Further, the winding direction of the second primary side winding P2 with respect to the winding direction of the first primary side winding P1 (the direction away from the plane of the paper, as indicated by the X mark on the core of the wire). Is the opposite direction (the direction toward the paper surface, as indicated by the mark on the core of the line). When viewed from the side of the second flange 12, the winding direction of the first primary winding P1 is clockwise, whereas the winding direction of the second primary winding P2 is counterclockwise.

With the above construction, the winding directions of the first primary winding P1 and the second primary winding P2 are opposite, and the polarities are as shown in FIG. Moreover, the first
The winding start end (terminal 4) of the primary winding P1 and the winding start end (terminal 1) of the second primary winding P2 are the secondary windings S1 and S.
The winding end (terminal 3) end of the first primary side winding P1 and the winding end end (terminal 2) of the second primary side winding P2 are located near the midpoint of the secondary side winding S1. , S2 are located near the winding start end (or winding end end) of the first primary winding P.
The 1st and 2nd primary winding P2 will be arrange | positioned in the position which is electrically and magnetically equivalent (or symmetrical) with respect to the secondary winding S1 and S2. That is, the vertical current balance is good, the leakage inductance is small, that is, the coupling degree is good.

FIG. 3 shows a modification of the first embodiment.
In this pulse transformer, the insulating tape TP1 is wound between the first secondary winding S1 and the second secondary winding S2, and the first primary winding P1 to form the first secondary winding S1. The insulating tape TP2 is wound between the secondary winding S1 and the second secondary winding S2, and the second primary winding P2, and the required number of windings of the insulating tape TP2 are respectively wound. It is characterized by

According to the above modification, the insulating tape TP1,
By TP2, the insulation between the windings becomes more appropriate, and the number of turns of the insulating tapes TP1 and TP2 can be adjusted appropriately to reduce the degree of capacitive coupling and improve the vertical current balance.

The pulse transformer according to the second embodiment shown in FIG. 4 has a circuit configuration as shown in FIG. In other words, this pulse transformer is the first
The first primary winding P1a and the second primary winding P1b connected in parallel so as to connect the terminal 1 and the second terminal 2 grounded, and the third terminal 3 grounded. And the third terminal connected in parallel so as to connect between the fourth terminal 4 which is not grounded and
A first secondary winding S1 that connects between the primary winding P2a and the fourth primary winding P2b, and a non-grounded fifth terminal 5 and a grounded sixth terminal 6; The second secondary winding S2 that connects between the seventh terminal 7 and the eighth terminal 8 that is not grounded. The black circle marks in FIG. 5 represent the polarities of the windings.

Each of the windings P1a, P1b, P2a, P2
b, S1 and S2 are the first flange 2 shown in FIG.
It is wound on a bobbin 20 having a first and a second flange 22. FIG. 4 is a cross-sectional view of one side of the bobbin 20, showing the actual bobbin 20 and the windings P1a, P1b, P2.
a, P2b, S1 and S2 are 3 with the center line shown in the center
It has been rotated by 60 degrees. The arrow indicates the winding advance direction of the winding.

On the shaft 23 of the bobbin 20, the first primary winding P1a and the third primary winding P2a are bifilarly wound so that the winding start end and the winding end end have the same flange (here, the winding start end). Are wound in even layers (here, two layers) so as to be close to the first flange 21).

The first primary winding P wound by bi-fara
1a and a layer of the third primary winding P2a
The secondary side winding S1 and the second secondary side winding S2 are bi-farar windings, so that the winding start end and the winding end end are close to the same flange (here, the winding start end is the second flange 22). Thus, even layers (here, two layers) are wound.

The first secondary winding S wound by bi-fara
The second primary winding P1b and the fourth primary winding P2b have the same winding start end and winding end as the upper layers of the layers of the first and second secondary windings S2 due to the bi-fara winding. Even layers (here, two layers) are wound so that the flange (here, the winding start end) is close to the first flange 21.

The first primary winding P1a and the third primary winding P1a
Of the second primary winding P1b and the fourth primary winding P2b with respect to the winding turning direction of the primary winding P2a (the direction away from the paper surface as indicated by the x mark on the core of the wire). The turning direction is the reverse direction (the direction toward the paper as indicated by the mark at the core of the line). The first primary winding P1a and the third primary winding P2a rotate clockwise when viewed from the second flange 22 side, whereas the second primary winding P1b and the third primary winding P1a rotate in the clockwise direction. The winding direction of the primary winding P2b of No. 4 is counterclockwise.

With the above-described structure, the winding direction of the first primary winding P1a and the third primary winding P2a, the second primary winding P1b, and the fourth primary winding P1a. Line P
The winding rotation direction of 2b is the opposite direction, and the polarities are as shown in FIG.

Moreover, the first primary winding P1a and the third primary winding P1a
A winding start end and a winding end end of the primary winding P2a (terminals 1 to 1
4) and the winding start end and winding end end (terminals 1 to 4) of the second primary winding P1b and the fourth primary winding P2b are both in the secondary windings S1 and S2. It is located in the vicinity of the point and is arranged at a position that is electrically and magnetically equivalent (or symmetrical) with respect to the secondary windings S1 and S2. That is, in this transformer, the vertical current balance is good, the leakage inductance is small, that is, the coupling degree is good.

FIG. 6 shows a modification of the second embodiment.
In this pulse transformer, the insulating tape TP3 is provided between the first secondary winding S1 and the second secondary winding S2, and the first primary winding P1a and the third primary winding P2a. The first secondary winding S1 and the second secondary winding S2 are wound.
And a second primary winding P2b and a fourth primary winding Pb
Insulating tape TP4 is wound between
3 and TP4 are each characterized in that a required number of turns is provided.

According to the above modification, the insulating tape TP3,
By TP4, the insulation between the windings becomes more appropriate, the number of windings of the insulating tapes TP3 and TP4 is adjusted appropriately, the degree of capacitive coupling can be reduced, and the vertical current balance can be improved.

[0038]

As described above, according to the present invention, each winding of the primary winding, which is divided into two groups with the grounded terminal as the center, is coupled to the first secondary winding and the first winding. Since it is wound in a symmetrical positional relationship with the secondary winding of No. 2, it becomes an electromagnetically equivalent (or symmetrical) position, the longitudinal current balance becomes good, and the leakage inductance is reduced. The effect is small, that is, the degree of bonding is good.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a pulse transformer according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a pulse transformer according to the first embodiment of the invention.

FIG. 3 is a main-portion cross-sectional view of a pulse transformer according to a modification of the first embodiment of the invention.

FIG. 4 is a sectional view of a main part of a pulse transformer according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of a pulse transformer according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a main part of a pulse transformer according to a modification of the second embodiment of the present invention.

FIG. 7 is a diagram showing the arrangement of pulse transformers in ADSL.

FIG. 8 is a diagram showing a part related to a pulse transformer used in a circuit for data communication, among pulse transformers in ADSL.

FIG. 9 is a circuit diagram illustrating the operation of a pulse transformer used in ADSL.

FIG. 10 is a sectional view of a main part of a conventional pulse transformer.

[Explanation of symbols]

1 first terminal 2 Second terminal 3 Third terminal 4th terminal 5 Fifth terminal 6th terminal 7 7th terminal 8th terminal 10, 20 bobbins 11, 21 First flange 12,22 Second flange 13, 23 axis P1, P1a First primary winding P2, P1b Second primary winding P2a Third primary winding P2b Fourth primary winding S1 First secondary winding S2 Second secondary winding

Claims (4)

[Claims] 1. A first primary winding connecting a first terminal which is not grounded and a second terminal which is grounded, and a third terminal which is grounded and a fourth terminal which is not grounded. Second tying
Primary winding, a first secondary winding connecting between a non-grounded fifth terminal and a grounded sixth terminal, a grounded seventh terminal, and a non-grounded eighth terminal A second secondary winding connecting between the first winding and the second winding.
In a pulse transformer wound on a bobbin having a flange, the first and second secondary windings are bi-fara winding, and even-numbered layers are wound such that a winding start end and a winding end end are close to the same flange. And the first primary winding and the second primary winding are wound so that the winding start ends of the first primary winding and the second primary winding are close to the same flange, and the first primary winding and the second winding are wound. And a winding end of each of the primary windings of the second primary winding is wound so that the winding ends thereof are close to the same flange. A pulse transformer characterized in that the directions are opposite. 2. The first and second secondary windings are wound so as to be stacked while being sandwiched between the first primary winding and the second primary winding, Between the first and second secondary windings and the first primary winding, and between the first and second secondary windings and the second primary winding The pulse transformer according to claim 1, wherein the insulating tape is wound in a required number of turns. 3. A first and a second primary side windings connected in parallel so as to connect a first terminal which is not grounded and a second terminal which is grounded, and a third terminal which is grounded. A first and a third primary windings, which are connected in parallel so as to connect with a non-grounded fourth terminal, and a non-grounded fifth terminal and a grounded sixth terminal. Secondary side winding, and a second secondary side winding connecting between a grounded seventh terminal and an ungrounded eighth terminal, each of the first and second windings In a pulse transformer wound around a bobbin having a flange, the first and second secondary windings are wound by an even number of layers by bifarar winding so that a winding start end and a winding end end are close to the same flange. Since the first and third primary windings are bi-fara winding, the winding start end and the winding end end are the same. The even-numbered layers are wound so that the winding start end and the winding end end are close to the same flange by bi-fara winding, 2. A pulse transformer characterized in that winding directions of the second and fourth primary windings are opposite to winding directions of the first and third primary windings. 4. The first and second secondary windings are stacked in a state of being sandwiched between the first and third primary windings and the second and fourth primary windings. The first and second secondary windings and the first and third primary windings, and the first and second secondary windings and the first and second secondary windings. The pulse transformer according to claim 3, wherein the insulating tape having a required number of turns is wound between the second and fourth primary windings, respectively.