JPH0523503U - Surge absorber with built-in resistor - Google Patents

Abstract

(57) [Summary] [Purpose] In a surge absorber with a built-in varistor element and resistance element, the resistors of many parts can be formed at once, and the resistance value after resistance formation can be adjusted easily.
An object of the present invention is to provide a surge absorber capable of obtaining a constant resistance value. [Structure] A plurality of varistor green sheets having internal electrodes 9 and 10 formed thereon are pressure-bonded and fired to form a laminated body, and the internal electrodes 9 and 1 are formed.
Varistor component 5 formed with external electrodes 6 and 8 that conduct with 0
And a pair of electrodes 2 and 3 connected to both ends of the resistor 4 are formed on the surface of the insulating substrate 1. This is a surge absorber with a built-in resistor in which the external electrodes 6 and 7 of the varistor component 5 are electrically connected.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention consists of a resistor built-in surge absorber that absorbs and removes voltage surges and current surges that enter the line, and more specifically, a varistor element that suppresses voltage surges and a resistor element that suppresses current surges are composed of a single chip component. It is related to the formation of resistors in the surge absorber.

[0002]

[Prior Art]

 For example, a circuit combining a varistor element that suppresses a voltage surge and a resistor element that suppresses a current surge is employed as surge protection for a portion where the element is easily destroyed by an external surge, such as an IC input terminal.

By the way, if a circuit is configured by using separate parts for a varistor element and a resistance element, it takes time and labor to mount them on a printed circuit board, the work cost is high, and a large area is required in terms of space. Therefore, a surge absorber with a built-in resistor has been devised, which consists of a varistor element and a resistance element in one chip component.

The chip-shaped resistor built-in surge absorber shown in FIG. 5 is obtained by stacking a plurality of varistor green sheets provided with internal electrodes and press-bonding and firing to form a chip-shaped laminated body 11. The external electrodes 6, 7, 8 are formed on the outer surfaces of both ends and the intermediate portion, and the resistor 12 is formed by printing a resistance paste between the external electrodes 6, 7 on the upper end surface of the laminated body 11.

The external electrodes 6 and 7 at both ends are electrically connected to the resistor 12, one external electrode 6 is electrically connected to one side of an internal electrode which constitutes a varistor element, and the intermediate external electrode 8 is an internal part. Conduction is established with the other side of the electrode, a varistor element is formed at the laminated portion of the plurality of internal electrodes, and a resistive element is formed by the resistive element 12 coated and baked on the laminated body 11, whereby a single element is formed. As shown in the equivalent circuit of FIG. 7, a surge absorber with a built-in resistor including a varistor element Z and a resistance element R can be obtained in one chip-shaped laminated body 11.

Next, the surge absorber with a built-in resistor shown in FIG. 6 is one in which a resistance element is incorporated as a part of the internal electrode of the chip-shaped laminated body and integrally fired, and the resistor 13 is formed on the surface at both ends. A ceramic green sheet (which may be a varistor green sheet) formed by coating so as to reach is added to the varistor green sheet formed by coating the internal electrodes 9 and 10, and the sheets are vertically stacked to form a laminated body 11a. By forming 6, 7, and 8, it is possible to obtain a resistance built-in surge absorber of the equivalent circuit shown in FIG. 7 in which the varistor element Z and the resistance element R are built in the chip-shaped laminated body 11a.

[0007]

[Problems to be solved by the device]

 By the way, in the above surge absorbers with built-in resistors shown in FIGS. 5 and 6, the resistance elements 12 and 13 are formed by screen printing or the like to obtain resistance elements. Therefore, the resistance value of the resistance element is , 13 depending on the thickness and shape.

Therefore, in order to stably supply the resistance value of the product, it is necessary to control the thickness of the film during the formation of the resistor, the protrusion, the bleeding at the resistor interface during firing, and the like. Very difficult to manage.

Further, the laminated body of the chip varistor for forming the resistor is very small, and the work of directly printing on this element is very difficult.

The present invention has been made to solve the above problems, and resistors of a large number of components can be formed at one time, and the resistance value can be easily adjusted after the resistors are formed. It is an object of the present invention to provide a surge absorber with a built-in resistor that can obtain a constant resistance value.

[0011]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention proposes a varistor component that forms an external electrode that is electrically connected to the internal electrode in a laminated body obtained by pressure-bonding and firing a plurality of varistor green sheets having internal electrodes, and a resistor on the surface. A surge absorber with a built-in resistor, which is composed of a body and an insulating substrate on which a pair of electrodes connected to both ends of the resistor is formed, and which connects and conducts an electrode on the insulating substrate and an external electrode of the varistor component.

[0012]

[Action]

 The resistor is formed on the surface of the insulating substrate that is different from the varistor component, and the electrode connected to this resistor and the external electrode of the varistor component are electrically connected to form a surge absorber containing the resistor and varistor components. Therefore, the resistor can be formed on an insulating substrate that is different from the varistor part, and the resistor can be easily formed.In addition, the resistance value can be checked and corrected after the resistor is formed quickly and easily. it can.

[0013]

【Example】

 Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4 of the accompanying drawings. The same parts as those in the conventional example will be described with the same reference numerals.

In FIG. 1, reference numeral 1 denotes an insulating substrate made of alumina, which is in a state of a mother substrate before cutting each component. A plurality of pairs of electrodes 2 and 3 are formed on the insulating substrate side by side by means of printing, baking or the like, and the resistor 4 reaching both of the electrodes 2 and 3 is also formed by printing or baking. Formed by means.

After that, on the insulating substrate 1, the shape of the electrode of the resistor 4 is adjusted by laser trimming to adjust the resistance value so that a constant resistance value can be obtained.

Next, the chip varistor 5 is mounted on the insulating substrate 1 as shown in FIG. The chip varistor 5 is formed by pressure-bonding and firing a plurality of laminated varistor green sheets having internal electrodes formed thereon, and has external electrodes 6 and 8 that are electrically connected to the internal electrodes and external electrodes 7 that are not electrically connected to the internal electrodes. In this case, the external electrodes 6 and 7 of the chip varistor 5 are arranged so as to be connected to the electrodes 2 and 3 on the insulating substrate 1, respectively.

As a mounting method, an adhesive is first applied to the resistor 4 on the insulating substrate 1 and the chip varistor 5 is adhered thereto, and then flow soldering is performed to form the external electrodes 6, 7 of the chip varistor 5. The electrodes 2 and 3 on the insulating substrate 1 may be soldered.

As another method, after arranging the chip varistor 5 on the insulating substrate 1, each electrode may be soldered by reflow soldering.

After connecting the chip varistor 5 on the insulating substrate 1, the mother substrate of the insulating substrate 1 is divided for each chip varistor 5, and the insulation having the chip varistor 5 and the resistor 4 as shown in FIG. A surge absorber component with a built-in resistor is obtained by stacking it with the board 1.

FIG. 4 is a cross-sectional view of the surge absorber with a built-in resistor. The chip varistor 5 includes a varistor green sheet having internal electrodes 9 reaching the ends and a varistor green sheet having internal electrodes 10 reaching both sides. An external electrode 6 which is electrically connected to one of the internal electrodes 9 of the chip varistor 5 is connected and electrically connected to the electrode 2 of the insulating substrate 1. The other inner electrode 10 is electrically connected to the outer electrode 8. Further, the external electrode 7 is electrically connected to the electrode 3 of the insulating substrate 1.

The surge absorber with a built-in resistor according to the present invention thus forms an equivalent circuit shown in FIG. The external electrode 6 is connected to the surge input side, the external electrode 7 is connected to an IC or the like to be protected from the surge, and 8 serves as a ground terminal. The voltage surge invading from the power supply side is suppressed by the varistor element Z, and the current surge is suppressed. Is suppressed by the resistance element R.

The surge absorber with a built-in resistor according to the present invention is not limited to the one in the above embodiment, but may be implemented by appropriately modifying the number of laminated internal electrodes and the number of sheets of the chip varistor.

[0023]

[Effect of the device]

 As described above, according to the present invention, the resistor of the surge absorber with a built-in resistor is formed on the insulating substrate that is connected to the external electrode of the chip varistor, so that the resistor can be formed on the insulating substrate and the chip varistor It can be created in a short period because it can be performed in a process different from the process of forming. Further, the shape of the resistor can be adjusted on the insulating substrate by means such as laser trimming, and a constant resistance value can be easily obtained.

Further, if a plurality of resistors are simultaneously formed on the insulating substrate in the mother substrate state as in the embodiment, it is possible to collectively perform resistance formation, adjustment, and soldering with the chip varistor. Therefore, there is also an effect that workability before the division is improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a resistor formed on an insulating substrate.

FIG. 2 is a perspective view in which a chip varistor is arranged on an insulating substrate.

FIG. 3 is a perspective view of a surge absorber according to the present invention.

FIG. 4 is a sectional view of a surge absorber according to the present invention.

FIG. 5 is a perspective view of a conventional surge absorber.

FIG. 6 is a cross-sectional view of another example of a conventional surge absorber.

FIG. 7 is a circuit diagram of a surge absorber with a built-in resistor.

[Explanation of symbols]

 1 Insulating substrate 2,3 Electrode 4 Resistor 5 Chip varistor 6,7,8 External electrode 9,10 Internal electrode

Claims (1)

[Scope of utility model registration request] 1. A varistor component in which an external electrode is formed on a laminated body obtained by pressure-bonding and firing a plurality of varistor green sheets having internal electrodes formed thereon, a resistor on the surface, and a pair connected to both ends of the resistor. A surge absorber with a built-in resistor in which the electrodes on the insulating substrate are connected to the external electrodes of the varistor component for electrical connection.