JP3083882B2 - Multi-line surge protection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-line surge protection method.

[0002]

2. Description of the Related Art In recent years, integrated circuits and digital circuits of communication equipment and information equipment have tended to reduce the resistance to surges entering through input / output lines and increase the risk of damage to equipment. . So the case of a multi-output line for example output line number 3 wire, between lines (L _1, L ₂₎ as shown in FIG. 7 (a), the a (L _2, L ₃₎ and between (L ₃ L
₁ ) meanwhile, the bidirectional thyristors ZD ₁ , ZD ₂ ,
ZD ₃ or the input / output lines L ₁ ,
L between _2, L ₃ and the neutral point N, each connected to two-way thyristor ZD _1, ZD _2, ZD _3, positive invaded the input and output lines, the negative surge S _1, S _2, bidirectional thyristor ZD
When the voltage exceeds the breakdown voltage V _BO , a current flows through the thyristor ZD to protect the protected circuit G from surge. This method is a two-way thyristor Z
Since D is small , can be manufactured at low cost, and operates at high speed, it has begun to be widely used for protection of communication equipment.

[0003]

However, in the conventional method of connecting a bidirectional thyristor for each line of each input / output line as described above, the number of bidirectional thyristors must be increased with an increase in the number of input / output lines. Not only that, but the number increases in proportion to the number of input / output lines, not at a ratio of 1: 1. For example, as shown in FIG. 7C, when the number of input / output lines is five, the number of bidirectional thyristors ZD that must be inserted between the lines is ten, which is slightly more than three times that of the case where the number of input / output lines is three. In general, the number N of the bidirectional thyristors Z required when the number of lines is n is N = n! / 2! (N-2)! Given by (1). Therefore, as the number of input / output lines increases, the cost required for protection increases at an accelerating rate. In addition to this, in the conventional method using a plurality of bidirectional thyristors,
Since it is required that the surge protection capability and the breaking capability are the same, it is required that the withstand voltage _{VBO and} other characteristics of the bidirectional thyristor be uniform. However, there are many technical difficulties in satisfying this requirement, and even if it is possible, for example, thyristors having the same characteristics are selected from a large number of manufactured thyristors. Disadvantageous.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a protection means which can economically protect a protected circuit having a multi-input / output line and which can be easily achieved technically. .

[0005]

The object of the present invention is achieved by the following means. That is, as shown in the circuit diagram of FIG. 1, one reverse conducting thyristor T and two diodes D connected in series in the same direction, having a positive terminal connected to the cathode and a negative terminal connected to the anode. _11, D _{21,
D 12, D 22 ... D 1n} , diode circuit D of the input and output line number N to each set of D _{2n 1,} D _2, ... using a circuit consisting of D _N, the respective diode circuit D _1, D _2, .., D _N are connected to connection terminals T ₁ , T _{2 ,.}
Means to connect to the input / output lines L ₁ , L ₂ ... L _N.

[0006]

If this arrangement is adopted [action], for example, when a positive surge has entered between lines L ₁ and L ₂ in FIG. 1, [line L ₁ → T ₁ →
Diode D ₁₁ → reverse conducting thyristor T → diode D
_{When a} surge current I flows on the path of ₂₂ → T ₂ → line L ₂ ] and a negative surge enters between L ₁ and L ₂ , [line L ₂ → T ₂ → diode D ₁₂ → reverse conduction thyristor T →
A surge current I flows on the path of the diode D ₂₁ → T ₁ → line L ₁ ]. When a positive surge enters between the lines L ₃ and L ₄ [line L ₃ → T ₃ → diode D ₁₃ → reverse conduction
When a surge current I flows on the path of the type thyristor T → diode D ₂₄ → T ₄ → line L ₄ ] and a negative surge enters, [line L ₄ → T ₄ → diode D ₁₄ → reverse conducting type
A current flows through a path of the lister T → diode D ₂₃ → T ₃ → line L ₃ ]. This operation is performed in the same manner for a surge that has entered between other lines, so that the same function as that of the above-described conventional method can be obtained, and the following effects that cannot be obtained by the conventional method are obtained. The object of the invention can be achieved.

[0007]

According to the conventional method, as shown in FIG. 2, the number of thyristors, the number of diodes, and the number of input / output lines, a bidirectional thyristor equal to or more than the number of input / output lines is required. As it increases, the number of bidirectional thyristors increases dramatically. In contrast, in the present invention, only one reverse conducting thyristor and twice as many diodes as input / output lines are required. Moreover, the reverse conduction in the present invention
Type thyristors have a chip area 1/2 that of bidirectional thyristors.
Therefore, it can be manufactured at low cost . In addition, diodes are significantly less expensive than bidirectional thyristors. Therefore, according to the present invention, surge protection of multiple input / output lines can be economically performed as compared with the conventional method, and this economic effect increases as the number of input / output lines increases. One reverse
Since the surge protection of the multi-input / output line is performed by using the common thyristor in common, it is not necessary to make the characteristics such as the withstand voltage _VBO uniform as in the case of using a large number of bidirectional thyristors. Therefore, implementation is technically easy. In the present invention, the reverse conduction type thyristor is different from the reverse conduction type thyristor.
Two diodes always in series in the opposite direction to the lister
Because it is connected, a reverse conducting thyristor
Since a circuit can be formed by using the protection element, the degree of freedom in designing the protection element can be increased.

Although the present invention has been described above, when the surge protection method of the present invention is realized as a surge protection element, FIG.
Can be sold with the required diode circuit D ₁ number of input and output lines are, D ₂ ... D _N, one reverse conducting thyristor T as a component integrally molded with resin M as. However, it is also possible to improve the flexibility in mounting to a device, the flexibility in changing the number of input / output lines, and the like by performing the following. For example, FIG. 4A showing the case of three lines.
, The reverse conducting thyristor T and the diode circuit D ₁ ,
D _2, D ₃ respectively or separately molded resin M, reverse conducting thyristor T and a diode D as shown in FIG. 4 (b)
₁ ... divided D ₃ into two groups, or a resin mold M, even a reverse conducting thyristor T and a diode circuit D ₁ one group as shown in FIG. 4 (c), the remaining diode circuit D ₂ ... D ₃ As a group so as to easily cope with the increase in the number of input / output lines,
Flexibility in mounting can be provided. In FIG. 1, the connection terminal T ₁ is connected to ground, and the connection terminals T ₂ , T ₃
... connect the T _N to the line L ₂ ... L _N, it may consider the protection against surges entering the ground from the line L ₂ ... L _N. In this case, the reverse conducting thyristor T through which the current of each diode circuit flows in common and the diode circuits D ₁ and D ₂
It is economical to increase only the current capacity of the power supply. Further, the case of the multi-input / output line single-stage protection method has been described above, but the present invention can also be used for multi-stage protection. For example, in the multi-stage protection method, a plurality of impedances Z ₁ , Z ₂ , Z ₃ are connected in series with the input / output line L ₁ as shown in a two-line circuit shown in FIG. 5, and the characteristics differ between the lines L ₁ , L _2. The multi-stage protection is performed by connecting the bidirectional thyristors ZD ₁ , ZD ₂ , and ZD _3. For example, by applying the present invention as shown in the circuit diagrams of FIGS. Can be used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the present invention.

FIG. 2 is a diagram showing the relationship between the number of thyristors and the number of diodes used in the conventional method and the present invention, and the number of input / output lines.

FIG. 3 is an explanatory diagram of a configuration example when the present invention is realized as a surge protection element.

FIG. 4 is an explanatory diagram of another configuration example when the present invention is realized as a surge protection element.

FIG. 5 is an explanatory diagram of a multi-stage surge protection circuit.

FIG. 6 is an explanatory diagram of an application example of the present invention to a multi-stage surge protection circuit.

FIG. 7 is an explanatory diagram of a conventional surge protection method for a multi-input / output line.

[Explanation of symbols]

L _1, L ₂ ... L _N output line S _1, S ₂ positive, negative surge ZD ₁ ... ZD _N, ZD bidirectional thyristor G the protected circuit T reverse conducting thyristor _{D 11, D 21 ... D 1N} , D 2N diode D ₁ … D _N diode circuit T ₁ … T _N connection terminal M resin mold Z ₁ , Z ₂ , Z ₃ , Z Impedance

Claims (4)

(57) [Claims] A protected circuit to which a plurality of input / output lines are connected.
In a multi-line surge protection method for roads, one reverse conducting type
A first diode having a positive terminal connected to the cathode of the iristor
And the anode of the reverse conducting thyristor has a negative terminal.
The connected second diode is connected in series in the same direction.
A diode circuit that sets the two diodes thus obtained as one set,
The reverse conduction type corresponding to the number of input / output lines of the protected circuit
Two diodes connected in series to the thyristor and connected in series
Connected to the input / output line of the protected circuit.
A multi-line surge protection method characterized by performing surge protection. 2. The reverse conducting thyristor is connected to a first resin module.
And a plurality of input / output lines
The number of diode circuits corresponding to the paths is formed by the second resin mold.
Formed as a part, the first resin mold part and the
Connecting the second resin mold part to the input / output line
2. The multi-line surge protection method according to claim 1, wherein surge protection is performed . 3. The method according to claim 1, wherein the reverse conducting thyristor is a first resin module.
And the diode circuit
One or more sets are formed as resin mold parts
Then, the first resin molded part and the protected circuit are not inserted.
The plurality of resin modes combined according to the number of output lines
Connected to the input / output line for surge protection.
2. The multi-line surge protection method according to claim 1, wherein: 4. The reverse conducting thyristor is provided with a diode.
One or more sets of circuit circuits are connected in parallel to form the first resin mode.
Of the diode circuit.
Form one or more sets as a second resin mold part
The first resin mold part and the second resin mold
Connected to the input / output line for surge protection.
2. The multi-line surge protection method according to claim 1, wherein: