WO2005109455A1

WO2005109455A1 - Pulse transformer for communication

Info

Publication number: WO2005109455A1
Application number: PCT/JP2004/006606
Authority: WO
Inventors: Akio Konemori
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2004-05-11
Filing date: 2004-05-11
Publication date: 2005-11-17
Also published as: JPWO2005109455A1

Abstract

A two-layer conductor in the shape of a coaxial cable is wound around a spectacle-like core (1) by a plurality of turns. A central conductor (2) of the two-layer conductor is utilized as a primary winding while one end of the outer braided conductor (3) around the central wire (2) is grounded.

Description

Description Communication pulse transformer Technical field

The present invention relates to, for example, a communication pulse transformer for insulating a modulation / demodulation circuit from a power line. Background art

In a conventional pulse transformer, one turn of a linear conductor forms the primary winding, and a secondary winding is wound around the transformer core multiple times.

Then, a plurality of electrostatic shielding conductors (shield conductors) are arranged around the primary winding, and the plurality of electrostatic shielding conductors are alternately divided into two groups and connected to the potential fixing point.

This prevents electrostatic transfer surge (unnecessary noise) generated on the primary winding from entering the secondary winding, and causes malfunction of the gate pulse generation circuit connected to the secondary winding. Is prevented (for example, see Patent Document 1).

Here, for example, if a pulse transformer is installed between the modulation and demodulation circuit and the power line in order to use the power line as a signal communication line, the pulse transformer converts the modulated signal output from the modulation and demodulation circuit into a differential signal (differential signal). ) Is superimposed on the power line, but since the power line has a double reciprocating structure, the electric fields of the differential signals are canceled out with mutually opposite characteristics.

Therefore, even if the differential signal is superimposed on the power line, unnecessary radiation does not leak to the outside of the power line, and does not interfere with the reception of surrounding ordinary broadcast waves.

However, the capacitance between the primary and secondary windings of the pulse transformer Due to such coupling, the modulated signal output from the modulation / demodulation circuit may be transmitted directly to the secondary power line as a common mode signal.

The electric field of the common mode signal is not canceled out each other like the electric field of the differential signal, so that unnecessary radiation leaks out of the power line (in this case, the power line functions as an antenna for transmitting the common mode signal). May interfere with the reception of normal broadcast waves.

If the degree of coupling between the primary and secondary sides is increased to increase the transmission efficiency of the pulse transformer, the coupling capacity between the primary and secondary windings increases, and it is unnecessary to leak out of the power line. Radiation increases.

[Patent Document 1]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-270430 (Pages 4 to 6, FIG. 1) Since the conventional pulse transformer is configured as described above, the static pulse generated on the primary winding side is generated. The power transfer surge (unnecessary noise) is prevented from entering the secondary winding. For example, if the power supply is installed between a modulation / demodulation circuit and a power line, the modulation signal output from the modulation / demodulation circuit will be a common mode signal. However, since it is transmitted directly to the power line on the secondary side, unnecessary radiation may leak to the outside of the power line.

The present invention has been made to solve the above problems, and has as its object to provide a communication pulse transformer capable of suppressing transmission of a common mode signal from a primary side to a secondary side. Disclosure of the invention

In the communication pulse transformer according to the present invention, a coaxial cable-shaped double-layered wire is wound around a core a plurality of times, and a center wire of the double-layered wire is used as a primary winding, while one end of an outer braided wire of the center wire is used. Is grounded. As a result, transmission of a common mode signal from the primary side to the secondary side can be suppressed. Brief Description of Drawings

FIG. 1 is a perspective view showing a communication pulse transformer according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a two-layered conductor of the communication pulse transformer according to Embodiment 1 of the present invention.

FIG. 3 is a circuit diagram showing an application example of the communication pulse transformer according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing a communication pulse transformer according to Embodiment 2 of the present invention.

FIG. 5 is a perspective view showing a communication pulse transformer according to Embodiment 3 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1

FIG. 1 is a perspective view showing a communication pulse transformer according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view showing a two-layer conductor of the communication pulse transformer according to Embodiment 1 of the present invention. .

In the figure, an eyeglass-shaped core 1 is made of a magnetic material such as iron, for example, and has through holes la and lb.

The coaxial cable-shaped double-layered wire is wound around the eyeglass-shaped core 1 several times, and the center wire 2 constitutes the secondary winding, while the outer wire of the center wire 2 is formed. One end of the assembled wire 3 is grounded. One end of the ground wire 4 is connected to the outer braided wire 3 forming a two-layer wire, and the other end is connected to the ground.

The single-layer wire 5 is wound around the eyeglass-shaped core 1 multiple times to form a secondary winding.

FIG. 3 is a circuit diagram showing an application example of the communication pulse transformer according to the first embodiment of the present invention. In the figure, a modulation / demodulation circuit 11 is connected to a center conductor 2 which is a primary winding of a communication pulse transformer. Then, the communication data to be transmitted is modulated, and the modulated signal is output to the center conductor 2 of the communication pulse transformer, while the modulation signal to be received is input from the center conductor 2 of the communication pulse transformer and demodulated.

The single-layer conductor 5, which is the secondary winding of the communication pulse transformer, is connected to the power line 13 via the insulating capacitor 12.

Next, the operation will be described.

First, how to wrap the conductor around the eyeglass-shaped core 1 of the communication pulse transformer will be described.

First, a coaxial cable-shaped two-layered wire composed of the center wire 2 and the outer braided wire 3 is inserted from the near side of the through hole 1 a of the eyeglass-shaped core 1, taken out from the back side, and By being inserted from the back side of the through hole 1 b of the core 1 and taken out from the near side, it is wound around the eyeglass-shaped core 1.

The coaxial cable-shaped two-layer conductor is wound around the eyeglass-shaped core 1 several times, so that the center conductor 2 forms the primary winding. At this time, the outer braided wire 3 surrounding the center wire 2 is grounded to the ground via the ground wire 4.

In addition, the single-layer conductor 5 is, for example, located at the back of the through hole 1 a of the eyeglass-shaped core 1. Is inserted from the near side, is taken out from the near side, is further inserted from the near side of the through hole 1 b of the glasses-shaped core 1, is taken out from the back side, and is wound around the glasses-shaped core 1.

The single-layer wire 5 is wound around the eyeglass-shaped core 1 a plurality of times to form a secondary winding.

As shown in Fig. 3, when the power line 13 is used as a signal communication line, the modulation / demodulation circuit 11 and the power line 13 must be insulated. Installed between 11 and power line 13. .

Since the modulation / demodulation circuit 11 is connected to the center conductor 2 which is the primary winding of the communication pulse transformer, when modulating the communication data to be transmitted, the modulation signal is output to the center conductor 2 of the communication pulse transformer. I do.

Thus, when the modulation signal is output to the center conductor 2 of the communication pulse transformer, a current flows through the center conductor 2 so as to pass through the glasses-shaped core 1 of the communication pulse transformer. The voltage of the modulation signal is induced on the secondary side.

As a result, the modulated signal is output to single-layer conductor 5 which is the secondary winding of the pulse transformer for communication, and transmitted to a communication partner (not shown) via power line 13.

On the other hand, when a communication partner (not shown) outputs a modulated signal to power line 13, the modulated signal reaches single-layer conductor 5, which is the secondary winding of the pulse transformer for communication.

Thus, when the modulated signal reaches the single-layer conductor 5 of the communication pulse transformer, a current flows through the single-layer conductor 5 so as to pass through the glasses-shaped core 1 of the communication pulse transformer. The voltage of the modulation signal is induced on the primary side of. As a result, the modulated signal is output to the center conductor 2 which is the primary winding of the communication pulse transformer, and is input to the modulation / demodulation circuit 11.

Upon receiving a modulation signal output from a communication partner (not shown), the modulation / demodulation circuit 11 demodulates the modulation signal.

Here, when the modulation signal is output from the modulation / demodulation circuit 11 to the primary winding of the communication pulse transformer, the primary winding is not a coaxial cable-like two-layer conductor as shown in Fig. 2, but a simple single-layer conductor. In this case, the modulated signal on the primary side is directly transmitted to the secondary side as a common mode signal due to the capacitive coupling between the primary and secondary windings of the communication pulse transformer.

However, in the first embodiment, the primary winding of the communication pulse transformer is a coaxial cable-like two-layer conductor as shown in FIG. 2, and the center conductor 2 of the two-layer conductor is grounded at one end to ground. The common mode signal transmitted via the capacitive coupling between the primary winding and the secondary winding, which is wrapped by the outer braided conductor 3 It does not flow to the single-layer conductor 5, which is the next winding.

As is clear from the above, according to the first embodiment, the coaxial cable-shaped double-layered wire is wound around the eyeglass-shaped core 1 several times, and the center wire 2 of the double-layered wire is used as the primary winding. On the other hand, since one end of the outer braided conductor 3 of the center conductor 2 is grounded, transmission of the common mode signal from the primary side to the secondary side can be suppressed. This has the effect of suppressing unnecessary radiation leaking from the line 13. Embodiment 2

In Embodiment 1 described above, a case where a two-layer coaxial cable-like conductor and a single-layer conductor 5 are wound a plurality of times around an eyeglass-shaped core 1 provided with through holes la and 1b is described. 4 As shown in Fig. The communication pulse transformer may be configured by winding the coaxial cable-like two-layer conductor and the single-layer conductor 5 around the ring-shaped core 6 a plurality of times. The operation when the communication pulse transformer of FIG. 4 is applied to the circuit of FIG. 3 is the same as that of the communication pulse transformer of FIG.

The manner of winding the conductor around the ring-shaped core 6 of the communication pulse transformer shown in FIG. 4 is as follows.

First, a coaxial cable-shaped two-layered conductor consisting of a center conductor 2 and an outer braided conductor 3 is inserted, for example, from the near side of the through hole 6a of the left ring-shaped core 6 in the figure and taken out from the back side. Further, it is inserted into the through hole 6a of the right ring-shaped core 6 from the back side and taken out from the near side, so that it is wound around the two ring-shaped cores 6.

The coaxial cable-shaped two-layer conductor is wound around the two ring-shaped cores 6 a plurality of times, so that the center conductor 2 forms a primary winding. At this time, the outer braided wire 3 surrounding the center wire 2 is grounded to the ground via the ground wire 4.

In addition, the single-layer conductor 5 is inserted through the through hole 6 a of the ring-shaped core 6 on the left side in the figure, is taken out from the near side, and is further removed through the ring-shaped core 6 on the right side. By being inserted from the near side of the hole 6a and taken out from the back side, it is wound around the two ring-shaped cores 6.

The single-layer wire 5 is wound around the two ring-shaped cores 6 a plurality of times to form a secondary winding.

In the second embodiment, the coaxial cable-shaped two-layered conductor and the single-layered conductor 5 are wound around two ring-shaped cores 6, but the present invention is not limited to this. The coaxial cable-shaped two-layer wire and the single-layer wire 5 may be wound around the core 6, or the coaxial cable-shaped two-layer wire and the single-layer wire 5 may be wound around three or more ring-shaped cores 6. May be. Embodiment 3.

In Embodiment 1 described above, the coaxial cable-shaped two-layer conductor and the single-layer conductor 5 are wound around the eyeglass-shaped core 1 having the through holes la and 1b a plurality of times. As shown in FIG. 5, a coaxial cable-shaped two-layer conductor and a single-layer conductor 5 may be wound around the outer core 7 a plurality of times to form a communication pulse transformer.

The operation when the pulse transformer for communication of Fig. 5 is applied to the circuit of Fig. 3 is the same as that of the pulse transformer for communication of Fig. 1, but as shown in Fig. 5, When winding the two-layer coaxial cable and the single-layer conductor 5 around the core 7, the number of turns can be increased as compared with the case of winding around the eyeglass-shaped core 1 in Fig. 1 and the ring-shaped core 6 in Fig. 4. Therefore, there is an effect that it can be used in a lower frequency band than the first and second embodiments. Industrial applicability

As described above, the communication pulse transformer according to the present invention is, for example, provided between a modulation / demodulation circuit and a power line when a power line is used as a signal communication line, and insulates the modulation / demodulation circuit from the power line. It is suitable for use in modems for power communication.

Claims

1. The core wire is wound several times around the core to form a primary winding, while the outer braided wire of the center wire is grounded at one end of a coaxial cable, and the core wire is wound multiple times. And a single-layer conductor forming a secondary winding.

Contract

2. A coaxial cable-shaped cable is attached to the eyeglass-shaped core with two through holes.

2. The communication pulse transformer according to claim 1, wherein the double-layer conductor and the single-layer conductor are wound a plurality of times.

Enclosure

3. The communication pulse transformer according to claim 1, wherein a coaxial cable-shaped two-layer conductor and a single-layer conductor are wound a plurality of times around a ring-shaped core having a through hole. .

4. The communication pulse transformer according to claim 1, wherein a coaxial cable-like two-layer conductor and a single-layer conductor are wound a plurality of times around the outer core.