JPH089072A - Module resistor for high voltage protection - Google Patents

Abstract

PURPOSE:To promote miniaturization and economy of a subscriber circuit to the utmost with respect to the high voltage protection module resistor provided to the subscriber circuit of a digital exchange. CONSTITUTION:A module resistor 100 formed on a ceramic board is adopted for a high voltage protection resistor used to protect a subscriber circuit from a high voltage over a permissible voltage produced in a subscriber line. When a high voltage is applied to the module resistor 100, a heating part 200 at which a temperature rises rapidly is arranged in the middle of the module resistor 100, and a high voltage conduction path 300 is arranged to break the high voltage conduction path 300 in the module resistor 100 through which a high voltage is conducted by a crack 400 estimated to be produced in the module resistor 100 as a result of a temperature rise in the heating part 200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage protection module resistor provided in a subscriber circuit of a digital exchange.

[0002]

2. Description of the Related Art FIG. 6 is a diagram showing an example of a conventional subscriber circuit. It should be noted that FIG. 6 shows only the portion of the subscriber circuit of the digital exchange that is related to high voltage protection.

In FIG. 6, 1 is a fuse, 2 is a resistor,
3 is a varistor (VR), 4 is a diode, 5 is a relay contact, and 6 is an external terminal. External terminals (6 ₁ ) and (6
The _2), is connected subscriber line accommodated in the subscriber circuit, also the external terminal (6 _3), calling signal source sent to the subscriber line coming from the digital switching system is connected.

On the subscriber line (not shown), an unacceptably high voltage is generated in the subscriber circuit due to a lightning strike, a contact with the power line, or the like, and is applied to the external terminals (6 ₁ ) and (6 ₂ ). May be done.

Inside the subscriber circuit, there is provided means for preventing the destruction of the subscriber circuit, especially the semiconductor element, when the above-mentioned high voltage is applied to the external terminals (6 ₁ ) and (6 ₂ ). There is.

The fuses (1 ₁ ) and (1 ₂ ) serve to block large currents flowing into the subscriber circuit as a result of high voltage being applied to the external terminals (6 ₁ ) and (6 ₂ ). . The fuses (1 ₁ ) and (1 ₂ ) of the varistors (VR) (3 ₁ ) to (3 ₄ ) and the diodes (4 ₁ ) to (4 ₄ ) are blown after the high voltage is applied. By the time it does, it plays the role of suppressing the voltage applied to the power supply section in the subscriber circuit to be below the allowable level.

The varistor (VR) (3 ₁ ) and (3
₂ ) and diodes (4 ₁ ) and (4 ₂ ) protect the communication line to the power supply and also varistor (VR) (3
₁ ) and (3 ₂ ) and diodes (4 ₁ ) and (4 ₂ ) protect the speech current monitoring path to the power supply.

The fuses (1 ₁ ) and (1 ₂ ) are blown to the resistors (2 ₁₁ ) and (2 ₇₁ ) and (2 ₁₂ ) and (2 ₇₂ ) after the above-mentioned high voltage is applied. By the way, it plays a role of suppressing the current flowing into the power feeding unit via the above-mentioned communication line to be below the allowable level.

Further, the resistors (2 ₃₁ ) and (2 ₃₂ ) pass through the above-mentioned call current monitoring path after the above-mentioned high voltage is applied and before the fuses (1 ₁ ) and (1 ₂ ) are blown. Then, it plays the role of suppressing the current flowing into the power supply unit to be less than the allowable value.

From the above, the fuses (1 ₁ ) and (1
₂ ), resistance (2 ₁₁ ), (2 ₇₁ ), (2 ₁₂ ), (2 ₇₂ ),
(2 ₃₁ ) and (2 ₃₂ ), varistor (VR) (3 ₁ ) to (3 ₄ ) and diodes (4 ₁ ) to (4 ₄ )
Form a high voltage protection unit.

In the high voltage protection section, the resistance (2 ₁₁ ),
The resistance values of (2 ₁₂ ), (2 ₇₁ ) and (2 ₇₂ ) are relatively small [for example, the resistances (2 ₁₁ ) and (2 ₁₂ ) are 47 ohms, and the resistances (2 ₇₁ ) and (2 ₇₂ ) are 10 ohms. Ohm], a large current flows even when a high voltage is applied, and energy consumption increases, resulting in a large amount of heat generation.

As a result, the resistances (2 ₁₁ ), (2 ₁₂ ), (2
₇₁ ) and (2 ₇₂ ) are composed of winding resistors. On the other hand, relay contacts (5 ₁ ), (5 ₂ ) and resistance (2 ₆ )
Constitutes a ringing signal sending section and a ring trip section. When the relay contacts (5 ₁ ) and (5 ₂ ) operate, the ringing signal supplied from the external terminal (6 ₃ ) is transferred to the external terminal ( 6 ₁ ) and (6 ₂ ).

The resistors (2 ₈₁ ) and (2 ₈₂ ) serve to guide the voltage generated across the resistor (2 ₆ ) to a ring trip portion (not shown).

[0014]

As is apparent from the above description, in the conventional subscriber circuit, the resistors (2 ₁₁ ), (2 ₁₂ ), (2 ₇₁ ), and (2 ₇₁ ) which constitute the high voltage protection unit are used. _{Since 72} ) consisted of winding resistors, the dimensions of individual resistors also increased.

Further, the resistors (2 ₁₁ ), (2 ₁₂ ), (2 ₇₁ )
Since the above-mentioned high voltage is applied to the conductors on the printed circuit board constituting the subscriber circuit connected to (2 ₇₂ ) and (2 ₇₂ ), there is a risk of discharge if the conductors are brought too close to each other,
Since it is necessary to keep the distance between the conductors above a certain level,
It is not possible to improve the packing density of the components on the subscriber circuit, and there is a problem that the miniaturization and economy of the subscriber circuit are impaired.

It is an object of the present invention to realize a high voltage protection unit that promotes miniaturization and economy of subscriber circuits.

[0017]

FIG. 1 is a diagram showing the principle of the present invention. FIG. 1 (a) shows the principle of the present invention [claim 1], and FIG. 1 (b) shows the present invention. The principle of claim 4] will be shown.

In FIG. 1, 100 is a module resistance,
Reference numeral 200 is a heat generating portion, 300 is a high-voltage conduction path, 400 is a crack, and 500 is a weight part. In the present invention, the high-voltage protection resistor for protecting the subscriber circuit from the unacceptably high voltage coming from the subscriber line is formed by the module resistor (100) formed on the ceramic substrate.

[0019]

According to the present invention (Claim 1), when the high voltage is applied to the module resistor (100), the heating portion (200) whose temperature rises most is changed to the module resistor (10).
It is placed in the central part of 0).

Further, as a result of the temperature rise of the heat generating part (200),
A crack (400) expected to occur in the module resistance (100) cuts the high voltage conduction path (300) through which the high voltage is conducted in the module resistance (100). Deploy.

The heat generating part (200) is disposed only on one surface of the module resistor (100), and the temperature of the surface opposite to the module resistance (100) is higher than that of the heat generating part (200). It is considered to arrange a low heat section.

It is also envisaged that the high voltage conduction path (300) be arranged so that it will be cut simultaneously at at least two or more locations by the crack (400). Furthermore, as mentioned above,
When a crack (400) occurs in the module resistor (100), a weight part (500) having the largest weight among the components mounted in the module resistor (100) is supposed to be easily removed. Deploy.

Therefore, as a result of realizing the high-voltage protection resistance and the high-voltage conduction path by the module resistance, miniaturization and economy of the subscriber circuit are promoted, and high voltage is generated when a high voltage is generated on the subscriber line. The voltage conduction path is cut off quickly, and the role of high voltage protection is enhanced.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 2 is a diagram showing a subscriber circuit according to an embodiment of the present invention, FIG. 3 is a diagram showing a module resistor according to an embodiment of the present invention, and FIG. 4 is an example of a mounted state of the module resistor in FIG. FIG. 5 is a diagram showing an example of the high voltage interruption state in FIG. 3. The same reference numerals indicate the same objects throughout the drawings.

Also in FIG. 2, as in FIG.
Related to high voltage protection in subscriber circuit of digital exchange
Only the part to do is shown. Subscriber times shown in Figure 2
6 is different from the subscriber circuit shown in FIG.
All of the resistors (2₁₁),
(2₁₂), (2₇₁) And (2₇₂) And shown in FIG.
All other resistances (2_{twenty one}), (2_{twenty two}),
(2₃₁), (2₃₂), (2₄₁), (2₄₂), (2₆),
(2₈₁) And (2₈₂), But in FIG.
As shown in FIG. 3, a thick film resistor is formed on the ceramic substrate.
Two module resistors made (10) [individual module
Resistance (10 _A) And (10_B), Below
The same applies to the subscriber circuit as shown in FIG.
On the printed circuit board (20) of₁) Or
(11₁₁) Is installed.

The resistance (2₁₁),
(2₇₁), (2_{twenty one}), (2₃₁), (2₄₁), (2₈₁)
Is the resistance (2_1A), (2_7A), (2_2A), (2_3A),
(2_4A), (2 _8A) As module resistance (10_A)so
Composed of resistors (2_1B), (2_7B), (2_2B),
(2_3B), (2_4B), (2_8B) Is the resistance (2_1B), (2
_7B), (2 _2B), (2_3B), (2_4B), (2_8B) As
Module resistance (10_B) And further shown in FIG.
One resistor (2₆) Is two resistors in FIG.
(2 _6A) And (2_6B) And each module
Resistance (10_A) And (10_B).

The purpose of separating the resistor (2 ₆ ) into two resistors (2 _6A ) and (2 _6B ) is to separate each module resistor (1
This is to equalize the mounting area of each resistor (2) in 0 _A ) and (10 _B ).

However, the subscriber circuit shown in FIG.
There is no difference in circuit function from the subscriber circuit shown in FIG. Further, fuses (1 ₁ ) and (1 ₂ ) are also mounted as fuses (1 _A ) and (1 _B ) on the module resistors (10 _A ) and (10 _B ), respectively.

In FIGS. 3 (a) and 3 (b), the front surface and the back surface are displayed in a state in which _{one of} the terminal pins (11 ₁ ) to (11 ₁₁ ) is projected on a mirror surface so that they are in the same arrangement. ing.

When a high voltage is generated on the subscriber line connected to the external terminals (6 ₁ ) and (6 ₂ ) shown in FIG. 2, the high voltage is generated by the terminal pin (11 ₁₀ ) of each module resistor (10). ), And the lead wire (9
₄ ), the fuse (1) and the lead wire (9 ₉ ) to be output to the terminal pin (11 ₅ ), and the lead pin (1) via the lead wire (not shown) on the printed circuit board (20) of the subscriber circuit.
It is output to the terminal pin (11 ₂ ) via the conductor (9 ₁ ), the resistance (2 ₁ ), (2 ₇ ) and the conductor (9 ₃ ) which are connected to the surface ₁₁ 1) and are mounted on the surface, and the subscriber. It is transmitted to a power supply unit (not shown) in the circuit.

Further high voltage applied to the terminal pin (11 _10), the back surface of the conductor (9 _4), the fuse (1), lead (9
₉ ) and resistor (2 ₃ ) via terminal pin (1
It is also output to 1 ₁ ) and is transmitted to the above-mentioned power feeding unit.

Therefore, in FIG. 3, the shaded path corresponds to the high voltage conduction path (300) in FIG. 1, and most of the wiring related to the high voltage is the module resistance (1).
0), the wiring on the printed circuit board (20) on which the module resistor (10) is mounted need not be widened in consideration of high voltage.

As described above, when the high voltage is applied to the terminal pin (11 ₁₀ ), the resistor (2 ₁ ) which consumes the most power and has the highest temperature rise is the heating unit (20) in FIG.
0) is mounted at the center of the front surface of the module resistor (10) together with the resistor (2 ₇ ) directly connected to the resistor (2 ₁ ), while the resistor (2 ₇ ) is mounted on the back surface of the module resistor (10). Resistors (2 ₂ ) to (2 ₆ ) and (2 ₈ ) with less power consumption and less temperature rise than (2 ₁ )
And have been implemented.

Therefore, when a high voltage is applied to the terminal pin (11 ₁₀ ), the surface side of the module resistor (10) expands due to the temperature rise of the resistor (2 ₁ ), but the back surface of the module resistor (10). The side does not expand as much as the surface side.

As a result, the module resistance (10) is curved to the surface side, and a crack (400) is generated along the dotted line shown in FIGS. 5 (a) and 5 (c) [the present invention (claims 1 and 2)]. Example of].

As shown in FIGS. 5 (a) and 5 (c), the crack (400) replaces the resistors (2 ₁ ) and (2 ₇ ) forming the high voltage conduction path (300) with the module resistance ( 10) Cut at the surface of the high voltage conduction path (30
0) constituting the conductors (9 ₄ ), (9 ₉ ) and resistance (2
₃ ) is cut at the back surface of the module resistor (10), and it is possible to prevent the high voltage from being transmitted to a power supply unit (not shown) or the like, like the fuse (1).

By cutting the high-voltage conduction path (300) at two or more places, it is possible to prevent the occurrence of discharge at the cracked portion, and to quickly cut off the high voltage [in the present invention (claim 3)]. Example〕.

Further, the module resistor (10) has a relatively large weight among the parts constituting the high voltage protection part along the back surface, particularly along the edge opposite to the terminal pins (11 ₁ ) to (11 ₁₁ ). By mounting the fuse (1), the portion surrounded by the crack (400) of the module resistor (10) falls, and the high-voltage cutoff effect is further ensured [implementation of the present invention (claim 3)]. Example].

As is clear from the above description, according to the present embodiment, the fuses (1 _A ) and (1 _B ) forming the high voltage protection circuit of the subscriber circuit, and the various resistors (2 _1A ) to (2). _8A ) and (2 _1B ) to (2 _8B ) are distributedly mounted on two sets of module resistors (10 _A ) and (10 _B ),
Only the surface of each module resistor (10) has a heating part (20
By mounting a resistor (2 ₁ ) that becomes 0), when a high voltage is generated in the subscriber line accommodated in the subscriber circuit,
A crack (400) occurs in each module resistor (10) and a part of it drops, cutting the high-voltage conduction path (300) at two or more places, so that high voltage is quickly applied to the subscriber circuit. It will be cut off.

It is to be noted that FIGS. 2 to 5 are merely embodiments of the present invention, and the subscriber circuit to which the present invention is applied is not limited to that shown in the drawings, and many other circuits are possible. Modifications are considered, but in any case, the effect of the present invention does not change. Further, the configuration of the module resistor (100) is not limited to the module resistor (10) shown in the figure, and various modifications can be considered, but in any case, the effect of the present invention does not change. Further, the heat generating portion (2
00) is not limited to the illustrated resistance (2 ₁ ), and many other modifications can be considered, but the effect of the present invention does not change in any case. Also, the high voltage conduction path (30
0) is not limited to what is shown in the figure, and many other modifications can be considered, but the effect of the present invention does not change in any case. Further, the location where the crack (400) is generated is not limited to that shown in the figure, and many other deformations may be considered, but in any case, the effect of the present invention does not change. Also, the weight part (500) is the fuse (1) shown.
The present invention is not limited to the above, and many other modifications can be considered, but in any case, the effect of the present invention does not change.

[0041]

As described above, according to the present invention, in the subscriber circuit, the high-voltage protection resistance and the high-voltage conduction path are realized by the module resistance, and as a result, the miniaturization and economicization of the subscriber circuit are promoted, Further, when a high voltage is generated on the subscriber line, the high-voltage conduction path is quickly cut off, and the role of high-voltage protection is enhanced.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a diagram showing a subscriber circuit according to an embodiment of the present invention.

FIG. 3 is a diagram showing module resistance according to an embodiment of the present invention.

FIG. 4 is a diagram showing an example of a mounted state of the module resistors in FIG.

5 is a diagram showing an example of a high voltage interruption state in FIG.

FIG. 6 is a diagram showing an example of a conventional subscriber circuit.

[Explanation of symbols]

 1 Fuse 2 Resistor 3 Varistor (VR) 4 Diode 5 Relay Contact 6 External Terminal 9 Conductor 10, 100 Module Resistor 11 Terminal Pin 20 Printed Circuit Board 200 Heat-generating part 300 High Voltage Conduction Path 400 Crack 500 Weight part

Claims (4)

[Claims] 1. A subscriber circuit for accommodating a subscriber line in a digital exchange, wherein a high-voltage protection resistor for protecting the subscriber circuit from a high voltage exceeding an allowable voltage generated in the subscriber line is provided on a ceramic substrate. The module resistor (100) formed in the above, and when the high voltage is applied to the module resistor (100), the heat generating part (200) with the highest temperature rise,
The crack (40) is disposed in the central portion of the module resistor (100) and is assumed to be generated in the module resistor (100) as a result of the temperature rise of the heat generating unit (200).
0) arranging said high voltage conduction path (300) so as to disconnect said high voltage conduction path (300) through which said high voltage is conducted in said module resistor (100). Module resistance for. 2. The heat generating part (200) is disposed only on one surface of the module resistor (100), and the heat generating part (2) is disposed on the opposite surface of the module resistor (100).
2. The high-voltage protection module resistor according to claim 1, wherein a low-heat portion having a smaller temperature rise than that of (00) is arranged. 3. The high voltage protection module resistor according to claim 1, wherein the high voltage conduction path (300) is arranged so as to be simultaneously cut at at least two places by the crack (400). 4. In a subscriber circuit for accommodating a subscriber line in a digital exchange, a high-voltage protection resistor for protecting the subscriber circuit from a high voltage exceeding the allowable voltage generated in the subscriber line is provided on a ceramic substrate. The module resistor (100) formed in the above, and when the high voltage is applied to the module resistor (100), the heat generating part (200) with the highest temperature rise,
The crack (40) is disposed in the central portion of the module resistor (100) and is assumed to be generated in the module resistor (100) as a result of the temperature rise of the heat generating unit (200).
0) arranges the high-voltage conduction path (300) so as to disconnect the high-voltage conduction path (300) through which the high voltage is conducted in the module resistance (100), , The crack (400)
High-voltage protection characterized by disposing the weight part (500) having the largest possible weight among the components mounted on the module resistor (100) in a portion that is likely to be dropped when the above occurs. Module resistance for.