JP4679006B2 - Pulse transformer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulse transformer applicable to, for example, ADSL (Asymmetrical Digital Subscriber Line).
[0002]
[Prior art]
As shown in FIG. 7, in ADSL, a pulse transformer PT1 is arranged in parallel with a circuit formed by a capacitor C1 and a coil L1 for passing a 16 Hz bell signal to a general telephone line 101, and a telephone, a facsimile machine or the like is connected thereto. The In addition, an insulating pulse transformer PT2 is connected to the general telephone line 101 via a capacitor C2, and a data communication transmission / reception circuit is connected to the pulse transformer PT2.
[0003]
In the above, the pulse transformer PT2 is provided to perform data communication by superimposing a signal having a frequency higher than the voice frequency band on the general telephone line 101, and the frequency handled is 30 KHz or more. As described above, 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 signal level to be handled is also low.
[0004]
The pulse transformer PT2 is required to have a longitudinal current balance characteristic. Here, the vertical currents are currents Ia and Ib that flow in the same direction in the balanced two conductors using the ground as a return path using the electric wires of the general telephone line 101 as shown in FIG.
[0005]
As shown in FIG. 8, the general telephone line 101 is a balanced line that extends around the air to homes and the like, so unnecessary broadcast radio waves N1, urban noise N2, and the like are pair-wired in common mode. May overlap.
[0006]
[Problems to be solved by the invention]
Therefore, in the pulse transformer PT2 used on the data communication side, when the longitudinal current balance is poor, the common-mode unnecessary wave component appears on the secondary side of the pulse transformer PT2, and the data communication quality deteriorates. Invite
[0007]
On the other hand, in the pulse transformer PT1, the frequency handled is as low as about 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 as high as that of the pulse transformer PT2 is not required.
[0008]
A 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 and the ground, currents I1 and I2 flow to the primary side coil, and the first primary side coil P1 causes a solid line. A magnetic flux F1 indicated by a broken line is generated by the second primary coil P2. Here, something (DCR (resistance value when a direct current is passed), number of turns, stray (floating capacitance between windings), secondary side in the first primary coil P1 and the second primary coil P2 If there is a difference in the degree of coupling with the coil S, etc., a difference occurs in the magnetic fluxes F1 and F2.
[0009]
If there is no difference between the magnetic fluxes F1 and F2, the directions are opposite to each other and cancel each other. However, when there is a difference, an induced voltage is generated in the secondary coil S according to the difference. In this case, as the frequency is higher, the common mode signal SIG is more likely to be generated, making it difficult to achieve a balance.
[0010]
Conventionally, in the pulse transformer PT2 as shown in FIG. 9, in order to ensure sufficient coupling between the primary side and the secondary side, the first secondary winding S1 and the second secondary winding S2 are provided. Make a bifara roll and balance. A structure is employed in which the first secondary winding S1 and the second secondary winding S2 wound by the above-described bi-directional are sandwiched between the first primary winding P1 and the second primary winding. . FIG. 10 shows a cross-sectional side view of the bobbin 100. The actual bobbin 100 and the windings P1, P2, S1, and S2 are in a state of being rotated 360 degrees around the center line shown in the drawing.
[0011]
The arrows in FIG. 10 indicate 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, 2 primary windings P <b> 2 are wound from the second terminal 2 side close to the first flange 101 to the first terminal 1 side close to the second flange 102. In addition, the first secondary winding S1 and the second secondary winding S2 are second from the fifth terminal 5 and the seventh terminal 7 side close to the second flange 102 by bi-directional winding. The sixth terminal 6 and the eighth terminal 8 that are close to the flange 102 are wound around.
[0012]
Therefore, when the first primary winding P1 and the second primary winding P2 are compared, the positions of the first terminal 1 and the fourth terminal 4, which are corresponding terminals, are the first secondary winding. The side winding S1 and the second secondary 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. The secondary winding S1 and the second secondary winding S2 are arranged under different electrical and magnetic conditions. That is, it was not an arrangement in which the longitudinal current balance could be taken.
[0013]
The present invention has been made in view of the circumstances as described above, and its purpose is, for example, to improve the longitudinal current balance in a pulse transformer used on the data communication circuit side in ADSL, reduce leakage inductance, that is, improve the coupling degree. It is to provide what you did.
[0014]
[Means for Solving the Problems]
A pulse transformer according to claim 1 of the present invention has first and second flanges, a bobbin around which each winding is wound between the first flange and the second flange, and a winding start end. third terminal is grounded is the first primary winding and the winding finish end connecting between the second terminal grounded is the first terminal and the winding finish end not grounded is the grounded and the second primary winding connecting between the fourth terminal which is not grounded is wound starting end, with a fifth terminal and the winding finish end not grounded is wound starting end A second secondary winding connecting between the first and second terminals, a seventh terminal that is grounded and grounded, and an eighth terminal that is grounded and not grounded. 2 secondary windings, and the first and second secondary windings are bi-directional by winding, The start end and the winding finish end are an even layer wound so as to be close to the same second flange, the first primary winding and the second primary coil winding start end is the same first respective The first primary side winding and the second primary side winding of each of the first primary side winding and the second primary side winding are wound so as to be close to the same second flange, The winding direction of the second primary winding is opposite to the winding direction of the first primary winding.
[0015]
The pulse transformer according to claim 2 of the present invention is a laminate in which the first and second secondary windings are sandwiched between the first primary winding and the second primary winding. Wound between the first and second secondary windings and the first primary winding, the first and second secondary windings and the second winding. The insulating tape having a required number of turns is wound between the primary side windings.
[0016]
A pulse transformer according to a third aspect of the present invention has a first and a second flange, a bobbin around which each winding is wound between the first flange and the second flange, and a winding end end a first primary winding connecting between the second terminal grounded is the first terminal and the winding start end which is not grounded is, a first terminal that is not grounded is wound starting end A second primary winding that is connected to the second terminal that is the winding end and grounded, and a third terminal that is the winding end and grounded , and a winding start end that is not grounded And a fourth primary terminal winding between the third terminal and the fourth terminal which is the winding start end and is grounded and a fourth terminal which is the winding end end and which is not grounded . co-primary winding of, as a fifth terminal and the winding finish end not grounded is wound starting end A first secondary winding connecting between the sixth terminal is grounded, the eighth terminal is not grounded to a seventh terminal and the winding finish end of which is grounded is wound starting end A second secondary winding that connects the first primary winding and the second primary winding between the first terminal and the second terminal. The third primary winding and the fourth primary winding are connected in parallel between the third terminal and the fourth terminal, and are connected in parallel . The secondary winding of the second winding is wound by an even layer so that the winding start end and the winding end end are close to the same second flange, and the first and third primary windings are bi-directional. Accordingly, the even-layer winding so that the winding start end and the winding finish end are close to the same first flange, the second and fourth primary-side winding Bipha The winding is the even layers wound as the winding start end and the winding finish end are close to the same first flange relative to the first and third winding turning direction of the primary winding, the second and 4 is characterized in that the winding direction of the primary winding is opposite.
[0017]
In the pulse transformer according to claim 4 of the present invention, the first and second secondary windings are constituted by the first and third primary windings and the second and fourth primary windings. It is wound so as to be stacked in a sandwiched state, between the first and second secondary windings and the first and third primary windings, and between the first and second second windings. A required number of insulating tapes are wound between the secondary winding and the second and fourth primary windings, respectively.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a pulse transformer according to the present invention will be described below with reference to the accompanying drawings. In each figure, the same components are denoted by the same reference numerals, and redundant description is omitted. Each pulse transformer according to the present invention is also provided at the position of the pulse transformer PT2 shown in FIG.
[0019]
The pulse transformer according to the first embodiment shown in FIG. 1 has a circuit configuration as shown in FIG. In other words, the pulse transformer has a first primary winding P2 connecting between the first terminal 1 that is not grounded and the second terminal 2 that is grounded, and the third terminal 3 that is grounded and the first terminal 1 that is not grounded. A first secondary winding S1 connecting the fourth primary winding P1 connecting between the fourth terminal 4 and the fifth terminal 5 not grounded and the sixth terminal 6 grounded; And a second secondary winding S2 connecting the seventh terminal 7 that is grounded and the eighth terminal 8 that is not grounded. In FIG. 2, the black circle mark represents the polarity of the winding.
[0020]
The windings P1, P2, S1 and S2 are wound around a bobbin 10 having a first flange 11 and a second flange 12 shown in FIG. FIG. 1 shows a one-side sectional view of the bobbin 10. The actual bobbin 10 and the windings P1, P2, S1, and S2 are in a state of being rotated 360 degrees around the center line shown in the drawing. . An arrow indicates a winding advance direction of the winding.
[0021]
The first primary winding P1 is wound around the shaft 13 of the bobbin 10, the terminal 4 side close to the first flange 11 is the winding start end, and the terminal 3 side close to the second flange 12 is the end of winding. It is considered as an end. Here, the first primary winding P1 is wound only by one layer, but there is no limit to the number of layers.
[0022]
On the upper layer of the primary winding P1, the first secondary winding S1 and the second secondary winding S2 are bifurcated so that the winding start end and the winding end end are the same flange (here, , The even number layer (in this embodiment, two layers) is wound so as to be close to the second flange 12). Here, bifara winding means that two pairs of wires are aligned and wound.
[0023]
On the upper layer of the first secondary side winding S1 and the second secondary side winding S2 wound by the bi-directional, the same flange as the winding start end of the first primary side winding P1 (here, the first The flange 11) side is the winding start end, and the same flange (here, the second flange 12) side as the winding end of the first primary winding P1 is the winding end, and the second primary winding P2 is wound by the same number of layers as the first primary winding P1.
[0024]
Furthermore, the winding direction of the second primary winding P2 is opposite to the winding direction of the first primary winding P1 (the direction away from the paper surface as indicated by a cross in the core of the wire). (As indicated by a mark at the core of the line, the direction toward the paper surface). When viewed from the second flange 12 side, the winding direction of the first primary winding P1 is clockwise, whereas the winding direction of the second primary winding P2 is counterclockwise.
[0025]
Since it is configured as described above, the turning 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 winding start end (terminal 4) of the first primary winding P1 and the winding start end (terminal 1) of the second primary winding P2 are near the midpoint of the secondary windings S1 and S2. The winding end (terminal 3) end of the first primary winding P1 and the winding end end (terminal 2) of the second primary winding P2 are located at the winding start ends of the secondary windings S1 and S2. The first primary winding P1 and the second primary winding P2 are electrically and magnetically equivalent to the secondary windings S1 and S2. It is arranged at a position (or target). That is, the longitudinal current balance is improved, the leakage inductance is reduced, that is, the degree of coupling is improved.
[0026]
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, and the first secondary winding S1 is wound around 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 insulating tape having a required number of turns is wound respectively. It is characterized by that.
[0027]
According to the above modification, the insulation between the windings becomes more appropriate by the insulating tapes TP1 and TP2, the number of turns of the insulating tapes TP1 and TP2 is appropriately reduced, the degree of capacitive coupling is reduced, and the longitudinal current balance is improved. can do.
[0028]
The pulse transformer according to the second embodiment shown in FIG. 4 has a circuit configuration as shown in FIG. That is, the pulse transformer includes a first primary winding P1a and a second primary winding that are connected in parallel so as to connect the first terminal 1 that is not grounded and the second terminal 2 that is grounded. A third primary winding P2a and a fourth primary winding P2b connected in parallel so as to connect P1b to the third terminal 3 that is grounded and the fourth terminal 4 that is not grounded; Between the first secondary winding S1 that connects the fifth terminal 5 that is not grounded and the sixth terminal 6 that is grounded, and the seventh terminal 7 that is grounded and the eighth terminal 8 that is not grounded And a second secondary winding S2. In FIG. 5, the black circle mark represents the polarity of the winding.
[0029]
Each of the windings P1a, P1b, P2a, P2b, S1 and S2 is wound around a bobbin 20 having a first flange 21 and a second flange 22 shown in FIG. FIG. 4 shows a cross-sectional side view of the bobbin 20. The actual bobbin 20 and the windings P1a, P1b, P2a, P2b, S1 and S2 are rotated 360 degrees around the center line shown in the figure. It has become. Moreover, the arrow has shown the winding advance direction of a coil | winding.
[0030]
The first primary winding P1a and the third primary winding P2a are biaxially wound on the shaft 23 of the bobbin 20 so that the winding start end and the winding end end are the same flange (here, the winding start end is the first winding end). Are evenly wound (two layers here) so as to be close to the flange 21).
[0031]
On the upper layer of the first primary side winding P1a and the third primary side winding P2a wound by bi-directional, the first secondary side winding S1 and the second secondary side winding S2 are bi-directional. Thus, the even-numbered layer (here, two layers) is wound 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).
[0032]
On the upper layer of the first secondary side winding S1 and the second secondary side winding S2 wound by bi-directional, the second primary side winding P1b and the fourth primary side winding P2b are bi-directional. Thus, the winding start end and the winding end end are wound in an even number layer (here, two layers) so as to be close to the same flange (here, the winding start end is the first flange 21).
[0033]
Then, the second primary side winding P1a and the third primary side winding P2a are wound in the winding direction (the direction away from the paper surface as indicated by an X mark at the core of the wire). The winding direction of the wire P1b and the fourth primary winding P2b is the reverse direction (the direction toward the paper surface as indicated by the mark at the core of the wire). When viewed from the second flange 22 side, the winding direction of the first primary winding P1a and the third primary winding P2a is clockwise, whereas the second primary winding P1b and the third primary winding P1a 4 of the primary winding P2b is counterclockwise.
[0034]
Since it is configured as described above, the winding direction of the first primary winding P1a and the third primary winding P2a and the second primary winding P1b and the fourth primary winding P2b The winding direction is the reverse direction, and the polarity is as shown in FIG.
[0035]
Moreover, the winding start ends and winding end ends (terminals 1 to 4) of the first primary winding P1a and the third primary winding P2a, the second primary winding P1b, and the fourth primary winding. The winding start end and the winding end end (terminals 1 to 4) of the line P2b are both located near the midpoint of the secondary windings S1 and S2, and are electrically connected to the secondary windings S1 and S2. It is arranged at a magnetically equivalent (or target) position. That is, in this transformer, the longitudinal current balance is good, the leakage inductance is reduced, that is, the degree of coupling is good.
[0036]
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 insulating tape TP4 is wound between the first secondary winding S1 and the second secondary winding S2, and the second primary winding P2b and the fourth primary winding Pb. Each of the insulating tapes TP3 and TP4 is wound with a required number of turns.
[0037]
According to the above modification, the insulation between the windings becomes more appropriate by the insulating tapes TP3 and TP4, the number of turns of the insulating tapes TP3 and TP4 is appropriately reduced, the degree of capacitive coupling is reduced, and the longitudinal current balance is improved. can do.
[0038]
【The invention's effect】
As described above, according to the present invention, the primary windings that are coupled in two groups with the grounded terminal as the center are the first secondary winding and the second secondary winding. Since the winding is wound in a target positional relationship, the position is equivalent (or target) in terms of electromagnetics, the longitudinal current balance is good, the leakage inductance is low, that is, the degree of coupling Is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of main parts of a pulse transformer according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram of the pulse transformer according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view of a main part of a pulse transformer according to a modification of the first embodiment of the present invention.
FIG. 4 is a cross-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 an 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 for ADSL.
FIG. 10 is a cross-sectional view of a main part of a conventional pulse transformer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st terminal 2 2nd terminal 3 3rd terminal 4 4th terminal 5 5th terminal 6 6th terminal 7 7th terminal 8 8th terminal 10, 20 Bobbin 11, 21 1st Flange 12, 22 Second flange 13, 23 Shaft P1, P1a First primary winding P2, P1b Second primary winding P2a Third primary winding P2b Fourth primary winding S1 First 1 secondary winding S2 second secondary winding

Claims (4)

A bobbin having first and second flanges, each winding being wound between the first flange and the second flange;
A first primary winding that connects between a first terminal that is a winding start end and is not grounded and a second terminal that is a winding end end and is grounded;
A second primary winding that connects between a third terminal that is the end of winding and is grounded and a fourth terminal that is the start of winding and is not grounded;
A first secondary winding that connects between a fifth terminal that is a winding start end and is not grounded and a sixth terminal that is a winding end end and is grounded;
A second secondary winding that connects between a seventh terminal that is a winding start end and is grounded and an eighth terminal that is a winding end end and is not grounded;
Comprising
The first and second secondary windings are wound by an even layer so that the winding start end and the winding end end are close to the same second flange by bi-directional winding,
The winding start ends of the first primary winding and the second primary winding are wound so as to be close to the same first flange,
The winding ends of the first primary winding and the second primary winding of the second primary winding are wound so as to be close to the same second flange,
The pulse transformer, wherein the winding direction of the second primary winding is opposite to the winding direction of the first primary winding.   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, and the first and second windings are wound. Between the second secondary winding and the first primary winding, and between the first and second secondary windings and the second primary winding, respectively. The pulse transformer according to claim 1, wherein a number of windings of the insulating tape is wound. A bobbin having first and second flanges, each winding being wound between the first flange and the second flange;
A first primary winding connecting between the second terminal grounded is the first terminal and the winding start end which is not grounded is wound termination end,
A second primary winding that connects between a first terminal that is a winding start end and is not grounded and a second terminal that is a winding end end and is grounded;
A third primary winding that connects between a third terminal that is the end of winding and is grounded and a fourth terminal that is the start of winding and is not grounded;
A fourth primary winding that connects between a third terminal that is a winding start end and is grounded and a fourth terminal that is a winding end end and is not grounded;
A first secondary winding that connects between a fifth terminal that is a winding start end and is not grounded and a sixth terminal that is a winding end end and is grounded;
A second secondary winding that connects between a seventh terminal that is a winding start end and is grounded and an eighth terminal that is a winding end end and is not grounded;
Comprising
The first primary winding and the second primary winding are connected in parallel between the first terminal and the second terminal;
The third primary winding and the fourth primary winding are connected in parallel between the third terminal and the fourth terminal;
The first and second secondary windings are wound by an even layer so that the winding start end and the winding end end are close to the same second flange by bi-directional winding,
The first and third primary side windings are wound by an even layer so that the winding start end and the winding end end are close to the same first flange by bi-directional winding,
The second and fourth primary windings are wound by an even layer so that the winding start end and the winding end end are close to the same first flange by bi-directional winding,
A pulse transformer characterized in that the winding direction of the second and fourth primary windings is opposite to the winding direction of the first and third primary windings.   The first and second secondary windings are wound so as to be stacked in a state sandwiched between the first and third primary windings and the second and fourth primary windings. , Between the first and second secondary windings and the first and third primary windings, the first and second secondary windings and the second and fourth 4. The pulse transformer according to claim 3, wherein an insulating tape having a required number of turns is wound between the primary side windings.

Images