JPS62194746A - Protection circuit for wire telecommunication equipment using commercial power supply - Google Patents

Abstract

PURPOSE:To prevent a fault due to a voltage difference from being imposed onto a device main body without power disconnection at the power line side by providing a bypass protection circuit to the electronic equipment main body having a power line and a communication line. CONSTITUTION: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 10 consists of a parallel circuit comprising a surge absorbing element 13, a capacitor 11 and a resistor 12. When a surge voltage rapid in rising is invaded onto the communication lines L1, L2 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

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to OA type equipment such as facsimiles, computers, television cameras, cable broadcasting, button telephones, etc. that are connected to communication lines such as communication lines and commercial power lines. Concerning safety circuits for electronic equipment.

(Prior art) Overhead communication lines outdoors are connected to various types of equipment in control lines, cable broadcasting lines, telephone communication lines, etc. of various plants, and these various types of equipment are connected to power lines such as commercial power sources. The connected OA equipment, such as a facsimile, a computer terminal, and an electronic button telephone, are connected to a communication line and a commercial power line.

Existing telephone communication lines are ungrounded, have large line impedance and line-to-line impedance, and have a structure that easily generates high voltages.

Therefore, in existing telephone communication lines, a protector is installed at the boundary between the outdoor line and the subscriber line, as shown in the conventionally known part of FIG.
needed to be established. The protector 2 is connected to the subscriber line C line Ll.
, L2 and the ground El, for example, a gas lightning arrester element 3 for communication is connected, and the gas lightning arrester element 3 is connected by applying a high voltage.
The device body 1 was protected by discharging the voltage, consuming the voltage, and discharging it to the earth E1.

On the other hand, the majority of single-product power supplies employ a single-phase, two-wire system with a neutral ground, and generally have a structure in which one line is grounded to the earth E2 at the pole transformer 4. For that reason,
The power supply impedance and line impedance were extremely low, and there was little risk of high voltage. Therefore, it was not mandatory to install protectors on the commercial power lines 01 and 02.

In this case, a type in which a gas lightning arrester for power supply is connected between the commercial power line Ill, the port 2 and the large #AE2, although not shown, is also provided.

In any case, for communication lines and commercial power lines.

In view of the above circumstances, each case was handled individually.

(Problem to be solved by the invention) In the above-mentioned current situation, high voltage such as lightning surge is applied to the communication line Ll,
When applied from L2, the gas is discharged to the ground El by the discharge of the gas lightning arrester 3, but the potential of the ground E1 rises. As a result, the commercial power line DI is 02 and 11!
! Due to the potential difference between E2 and E2, a differential voltage flows into the device main body l.

Also, even if it is assumed that high voltage is applied to both lines at the same time, a voltage difference is unavoidable due to the difference in the impedance between each line and the line.Therefore, the voltage difference especially from the 1 communication line side can be applied to the main body of the device! There is a drawback that it flows into

However, the present invention has been developed in view of the above-mentioned circumstances, and aims to balance the voltage between the communication line side and the power line side of the main body of electronic equipment, reduce the voltage at the same time, and at the same time reduce the voltage from the commercial power source. That-L made it possible to prevent the descent.
[1]

(Structure of the Invention) A security circuit for wired communication equipment using a commercial power supply according to the present invention to achieve the above object is used in a wired communication equipment using a commercial power supply line to connect the commercial power supply line and the communication line. This is a safety circuit for bypassing abnormal voltage that occurs between surge absorbing elements, and is characterized by a configuration in which a capacitor and a resistor connected in parallel to a surge absorbing element are connected in series.

(Operation of the Invention) When a high voltage such as a lightning surge enters from either or both of the communication line and the power supply line and a differential voltage is generated, the differential voltage flows into the safety circuit used in the main body of the device. In this case, the voltage difference is discharged by the surge absorption element and becomes large jllBE2.
is released into the river. In this case.

The differential voltage, which rises quickly, is protected by a capacitor, and a resistive element prevents the power from dropping against the commercial power supply.

(Embodiment of the Invention) Figures 1 and 2 show an embodiment of the safety circuit of a wired communication device using a commercial power line according to the present invention. is a curve diagram explaining the operation.
Descriptions of conventionally known parts in the drawings will be omitted due to redundancy.

Therefore, the communication lines Ll, L2 of the device body l and the power line Il
A safety circuit 10.10 is connected in parallel to the device body l and [12. The protector 1181Q has a parallel circuit such as a capacitor 11 and a resistor 12 connected in series to a gas lightning protection element 13 as a surge absorbing element.The capacitor 11 is an element with large static capacity and low impedance. Further, as the resistor 12, an element 1 having a low initial resistance value, such as a positive temperature coefficient thermistor, is selected.

It is preferable to select a lightning arrester that starts firing later than the gas lightning arrester 3 of the subscriber protector 2 or the gas lightning arrester installed in the power source.

According to the above circuit configuration, when an impact voltage that rises quickly enters the communication lines Ll and L2, the gas lightning arrester element 3 is discharged, so that a differential voltage as shown in FIG. 2 is generated. The sudden rise portion (A) of the voltage difference is cut off by the low impedance capacitor 11, and at the same time, the voltage difference between the lines is absorbed by the discharge of the lightning element 13.

Further, as shown in part CB) of FIG. 2, the resistance element 12 blocks the inflow of the power source, thereby preventing the power source from decreasing.

In the above embodiment, if a three-pole structure is selected as the gas-input lightning arrester 13, it is sufficient to install one between the lines. It can be used even if the direction is not constant.

Figure rtS3 shows another embodiment, in which a gas lightning arrester 14 is used and its electrodes 14a, 14b, 14d are
, 14e to the communication lines Ll, L2 and the above capacitor 11.1
1 and resistor 12.12, and electrode 14c.
is connected to the ground E1 to form a safety circuit 15. According to this embodiment, one gas lightning arrester element 14
It is possible to absorb or reduce the voltage between each line at the same time.

FIG. 4 shows another embodiment in which each protector 20 is provided for each line of a large number of outside line side communication lines L'l - L'n.
．． Each safety device 28. A collective protector 8 is constructed by connecting the two with one common ground line 5. In this case, the common ground wire 5 is used to connect the safety circuit 10.10. To the safety circuit IO, the communication lines Ll and L2 on the extension side are connected to the electrodes 18a and 18c of the gas-filled three-pole lightning arrester 1B, and the commercial 'itt source line [+1] and the intermediate electrode 1 are connected to the D2.
8b are connected in series, and this intermediate electrode tab is connected to the common ground line 8. In this case, each commercial power drop ~ [l
n are commonly connected to the outlet C of the lead-in line, and as the gas lightning arrester 16, one that starts discharge later than the discharge start of the gas lightning arrester of the protector 2 is selected.

According to this embodiment, a potential difference is generated by the start of discharge of the gas lightning arrester element of one of the protectors 2 in response to a high voltage, and the gas-filled three-pole lightning arrester 16 connected to the safety circuit 10
The difference voltage is absorbed or reduced by discharging in whichever line.Since the communication line side and the commercial core line side are respectively connected in common, the gas-filled three-pole a lightning element 1B
and safety circuits can be shared in one set.

In the embodiment shown in FIG. 4 above, if it is not possible to connect the common ground wire 5 to the ground due to space constraints, etc., a gas-filled three-pole a lightning element 160. It is only necessary to add an attachment 17 that combines the safety circuit lO0 and the safety circuit lO0.The attachment 17 can be implemented with a screw terminal or a modular terminal connection structure.

(Effects of the Invention) As explained above, according to Suekan II, by providing a bypass safety circuit in the main body of an electronic device having a power line and a communication line, the main body of the device can be operated without shutting off the power on the power line side as in the past. The purpose was to absorb or reduce disturbances caused by voltage differences between the two. In particular, in the initial stage, we were able to provide an extremely simple safety circuit in which the capacitor and the gas lightning arrester were used to protect the subsequent drop in commercial power supply with a resistor, and also to cut off the follow-on current from the commercial power supply side.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of a security circuit for wired communication equipment using a commercial power supply according to the present invention.
FIG. 2 is an explanatory diagram of the same circuit, FIG. 2 is an operation explanatory curve diagram, FIG. 3 is an open circuit explanatory diagram showing another embodiment, and FIGS. 4 and 5 are explanations of the same circuit showing another embodiment. It is a diagram. 100 equipment body, 20. Joined Nagisa Safety Device. 10.15, ,Security circuit, 11. , capacitor, 120. Resistor, 13,1f3, Gas lightning protection element, L1-Ln, Communication line, 0l-On, Power line. Patent applicant: 001 Hakusan Seisakusho Co., Ltd. Agent
00. Patent Attorney Yoshi 11 Yoshiharu Figure 1

Claims (1)

[Claims] A safety circuit used in wired communication equipment that uses commercial power lines to bypass abnormal voltages that occur between commercial power lines and communication lines, and includes a capacitor and a resistor connected in parallel to a surge absorption element. A safety circuit for wired communication equipment that uses commercial power in a series-connected configuration.