KR900002717B1 - Protection circuit for wire telecommunication equipment using commercial power supply - Google Patents

Abstract

The circuit is for preventing the fault due to voltage difference without power disconnection. The protection circuit (10) is connected in parallel with communication lines (L1,L2) and power lines (D1,D2) of the equipment main body (1). The protection circuit consists of a parallel circuit comprising a surge absorbing element (13), a capacitor (11), and a resistor (12). When a surge voltage rapid is invaded onto the communication lines, an arrester (3) is operated to generate a difference voltage. The steep rise of the voltage difference is cut off by a capacitor (11) and the voltage difference between the lines is absorbed by the arrester (13).

Description

Security circuit for wired communication equipment using commercial power

1 is a circuit diagram of the present invention.

2 is a curve diagram for explaining the operation of the present invention.

3 is a circuit diagram showing another example of the present invention.

4 and 5 are circuit diagrams showing yet another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: device body 2: subscriber security device

10, 15: security circuit 11: condenser

12 resistance 13, 16 gas-sealed lightning arrester

L ₁ -L _n : Communication line D ₁ -D _n : Power line

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to security circuits for electronic devices such as facsimile machines, computers, automatic office work (OA) devices, television camera cable broadcasting, and button telephones connected to communication lines and commercial power lines.

Control lines of various equipments, wired broadcasting lines, telephone communication lines, and the like are connected to various outdoor equipments, and these various devices are connected to power lines such as commercial power supplies.

That is, for example, OA devices such as facsimile machines, computer terminal devices, and electronic button phones are connected to communication lines and commercial power lines.

In addition to the non-grounding method, the conventional telephony communication line has a structure in which both the line impedance and the line impedance are large and tend to generate high voltage.

Therefore, the existing telephone communication line, as shown in Figure 1, it was necessary to install the security device (2) at the boundary between the outdoor line and the subscription line.

The security device 2 is connected to the subscriber communication lines L ₁ and L ₂ and the ground E ₁ , for example, by the communication gas enclosed lightning arrester 3, and discharges the gas enclosed lightning arrester 3 upon application of a high voltage. The device body 1 was protected by discharging a high voltage to earth E ₁ .

On the other hand, the commercial power source adopts the single-phase three-wire system of most of the weighted grounds. In general, in the columnar transformer 4, the secondary shaft one-side line is grounded to the ground E ₂ . As a result, power and line impedance were very low and the risk of high voltage was low.

Therefore, it is not mandatory to install a security _{device on the} commercial power lines (D ₁ , D ₂ ). In this case, although not shown between the commercial power lines (D ₁ , D ₂ ) and the ground (E ₂ ), there is also shown that a gas-enclosed lightning rod for power supply is connected. Either way, the communication line and the commercial power line were treated separately in view of the above circumstances.

In this state, when a high voltage such as a lightning surge voltage is applied to the communication lines L ₂ and L ₂ , the high voltage is discharged to the large magnetic field E _{1 due} to the discharge of the gas encapsulated lightning protection element 3, but at this time, the ground E ₁ The potential of goes up.

As a result, a differential voltage flows into the apparatus body 1 due to the potential difference between the commercial power lines D ₁ and D ₂ and the ground E ₂ .

Moreover, even if it is assumed that high voltage is simultaneously applied to both the communication line and the commercial power line, the difference voltage cannot be avoided due to the difference between the respective lines and the line impedance. Therefore, in particular, there is a drawback that the difference voltage from the communication line shaft flows into the device body 1.

The present invention has been developed in view of the above situation, and its main purpose is to achieve voltage balance with the communication line side of the body of the electronic device and to reduce the voltage and prevent the power supply drop from the commercial power source.

In order to achieve the object of the present invention, a security circuit for a telecommunication line device using a commercial power supply to which the present invention is applied is used in a wired communication device using a commercial power line to bypass an abnormal voltage generated between a commercial power line and a communication line. The circuit structure of the capacitor connected in parallel with the surge absorption element and the resistor connected in series is characterized by the above-mentioned.

When a high voltage such as a lightning surge enters from either the communication line or the power line, or a voltage difference occurs, the difference voltage flows into the security circuit used in the device body.

In this case, the differential voltage is discharged by the surge absorption element and discharged to the ground E ₂ . At the same time, the sudden rise of the differential voltage is protected by a capacitor, which prevents the power supply from falling off as a resistor for commercial power.

1 and 2 are one embodiment of a security circuit of a wired communication device using a commercial power line according to the present invention. FIG. 1 is a circuit diagram, and FIG. 2 is a curve diagram illustrating the operation. Description of the conventionally well-known part of the drawings is omitted because it overlaps.

Thus, the security circuits 10 and 10 'are connected in parallel with the device body 1 to the communication lines L ₁ and L ₂ and the power supply lines D ₁ and D ₂ of the device body 1.

In the security circuit 10, the parallel recall of the capacitor 11 and the resistor 12 is formed in series with the gas encapsulation lightning element 13 as a surge absorption element.

As the capacitor 11, a device having a large capacitance and a low impedance is selected. As the resistor 12, an element having a low initial resistance value, for example, a static thermistor is selected.

In addition, it is preferable to select the gas-sealed lightning arrester 3 having a later start of discharge than the gas-sealed lightning arrester for subscribers. According to the above circuit arrangement, when the rapid shock voltage rising suddenly is applied to the communication lines L ₁ and L ₂ , the gas-sealed lightning arrest element 3 discharges, so that the difference voltage as in FIG. 2 is generated.

As the differential voltage rises rapidly, (A) is cut off by the low-impedance condenser 11, the differential voltage between each line is absorbed by the discharge of the gas-sealed lightning arrest element 13.

In addition, as indicated by the portion B in FIG. 2, the inflow to the power supply side is prevented by the resistance element 12, thereby preventing the power supply from being lowered. In such an embodiment, if a three-pole structure is selected as the gas encapsulation lightning element 13, one may be provided between the lines. At this time, the grounding side of the commercial power supply line is unknown, and the plugging direction can be handled even if the insertion plug is not fixed. That is because there are security circuits on two commercial power lines.

FIG. 3 shows another example of the electrodes 14 _a , 14 _b , 14 _d , and 14 _e connected to the communication line L _1- L ₂ , the condenser 11, and the resistor by using the gas-sealed lightning arrester 14. at the same time connected to 12, but by connecting the electrode (14 _c) to the ground (E ₁₎ to form a security circuit (15).

According to this temporary embodiment, one gas-sealed lightning arrest element 14 can simultaneously absorb or reduce the mutual voltage between the respective lines.

4 shows another security device 2 installed at each line of a plurality of communication lines L ₁ '-L _n ' of a plurality of external shafts and connects each security device 2 to a common common wire 5. It consists of a collective security device (6).

In this case, the common circuit 5 is used to connect the security circuit 10. In the security circuit 10, the electrodes 16 _a , 16 _c of the gas-sealed tripole lightning arrester 16 are connected to the internal communication lines L ₁ , L ₂ , and at the same time, the middle of the commercial power lines D ₁ , D ₂ . The electrodes 16 _b are connected in series, and the intermediate electrode 16 _{b is} connected to the common lead 5.

In this case, the commercial power line (D ₁ -D _n ) was commonly connected to the outlet of the lead wire, etc. (C). Choose to be late.

According to this embodiment, a potential difference occurs due to the start of the discharge of the gas-sealed lightning arrester of either of the security devices 2 with respect to the high voltage, and the gas-sealed lightning arrester 16 to be connected to the security circuit 10 may be any line. By discharging, the difference voltage is absorbed or greatly reduced.

Since the common connection is made between the communication line side and the commercial power line side, the gas-encapsulated class 3 lightning protection element 16 and the security circuit can be shared in one pair.

In the embodiment of FIG. 4, when the ground connection 5 cannot be connected to the earth through common common ground 5, the gas-sealed tripole lightning element 16 and the security circuit 10 or the security circuit (as shown in FIG. What is necessary is just to add the connector 17 which combined 10).

The connector can be implemented with a screw terminal or a module terminal connection structure. As described above, according to the present invention, by installing a bypass security circuit on the body of the electronic device to which the power line and the communication line are connected at the same time, it is possible to prevent an obstacle due to the voltage difference on the body of the device without disconnecting power from the power line. To be resolved.

In particular, in the early period of overvoltage, the capacitor and the gas-sealed lightning arrestor could provide a very simple security circuit that can protect the subsequent commercial power supply drop with a resistance and also block the rapid breaking from the commercial power supply side.

Claims (1)

A security circuit for bypassing an abnormal voltage generated between a power supply line and a communication line used in a wired communication device using a commercial power supply line. The commercial power supply having a condenser connected in parallel with a surge absorber and a resistor connected in series is used. Security circuit for wired communication equipment to use.

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