JP2010098024A - Circuit protecting component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit protecting component capable of protecting an electronic apparatus even if not only an excessive voltage but also an excessive current is applied to it. <P>SOLUTION: The circuit protecting component has a fuse element 3 to connect end electrodes 2 at one side 1a of an insulating substrate 1, first and second external electrodes 4a, 4b provided at both ends of the insulating substrate 1 and connected to the end electrodes 2, first, second, and third extraction electrodes 5a, 5b, 5c formed at the other side 1b facing the one side 1a of the insulting substrate 1, and an excessive voltage protecting material layer 6 formed so as to at least cover spaces between the first extraction electrode 5a and the second extraction electrode 5b and between the second extraction electrode 5b and the third extraction electrode 5c, and formed of metal powder and resin. The first extraction electrode 5a and the third extraction electrode 5c are connected to the first external electrode 4a and the second external electrode 4b, respectively, and the second extraction electrode 5b is connected to the third external electrode 4c formed at the side of the insulating substrate 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit protection component for protecting an electronic device.

  This type of conventional circuit protection component is integrated by connecting an overcurrent protection unit that opens when an overcurrent is applied and an overvoltage protection unit that flows when an overvoltage due to static electricity or the like is applied in series. Had become.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 2007-82302 A

  Since the conventional circuit protection component described above is provided between the signal line and the ground, when an overvoltage is applied, the overvoltage can be released to the ground to protect the electronic device. If an electronic device is to be protected when a current is applied, it is necessary to form an overcurrent protection unit separately on the signal line. Therefore, in the conventional circuit protection component, when an overcurrent is applied Had the problem of not being able to protect electronic devices.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a circuit protection component that can protect an electronic device even when an overcurrent is applied as well as an overvoltage.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, there are provided end electrodes formed at both ends of one surface of the insulating substrate, a fuse element for connecting the end electrodes on one surface of the insulating substrate, and the insulating substrate. First and second external electrodes provided on both ends and connected to the end electrodes, and first, second and third lead electrodes formed on the other surface facing one surface of the insulating substrate And overvoltage protection comprising at least a portion between the first extraction electrode and the second extraction electrode and between the second extraction electrode and the third extraction electrode, and comprising metal powder and resin And connecting the first extraction electrode and the third extraction electrode to the first external electrode and the second external electrode, respectively, and connecting the second extraction electrode to the insulating substrate. This is connected to the third external electrode formed on the side. According to the above, by connecting the first and second external electrodes to the signal line and connecting the third external electrode to the ground, when an overvoltage is applied, the overvoltage is applied via the overvoltage protection material layer. It can escape to the ground to protect the electronic equipment, and if overcurrent is applied, the fuse element can be opened to protect the electronic equipment, so that not only overvoltage but also overcurrent was applied Even in this case, the electronic device can be protected.

  According to the second aspect of the present invention, in particular, the third external electrode is formed on one side of the insulating substrate and one on the other side, and the third external electrode is formed on the circuit protection component from the top. This is provided at a point-symmetrical position as seen, and according to this configuration, there is an effect that the directionality during mounting can be eliminated.

  In the invention according to claim 3 of the present invention, in particular, the current path flowing through the fuse element is made to meander, and according to this configuration, the inductance value of the fuse element can be increased. The overvoltage that could not be released to the ground via the overvoltage protection material layer can be removed by the fuse element, and this has the effect that the electronic device can be more reliably protected against the overvoltage.

  As described above, the circuit protection component of the present invention includes end electrodes formed at both ends of one surface of the insulating substrate, a fuse element that connects the end electrodes on one surface of the insulating substrate, and the insulating substrate. First and second external electrodes provided on both ends and connected to the end electrodes, and first, second and third lead electrodes formed on the other surface facing one surface of the insulating substrate And overvoltage protection comprising at least a portion between the first extraction electrode and the second extraction electrode and between the second extraction electrode and the third extraction electrode, and comprising metal powder and resin And connecting the first extraction electrode and the third extraction electrode to the first external electrode and the second external electrode, respectively, and connecting the second extraction electrode to the insulating substrate. Since it is connected to the third external electrode formed on the side surface, 1. By connecting the second external electrode to the signal line and connecting the third external electrode to the ground, when an overvoltage is applied, the overvoltage is released to the ground via the overvoltage protection material layer. The device can be protected, and when an overcurrent is applied, the fuse element can be opened to protect the electronic device, so that not only the overvoltage but also the overcurrent is applied. It has an excellent effect that the device can be protected.

  Hereinafter, a circuit protection component according to an embodiment of the present invention will be described with reference to the drawings.

  1 is a top view of a main part of a circuit protection component according to an embodiment of the present invention, FIG. 2 is a back view of the main part of the circuit protection component, and FIG. 3 is a cross-sectional view taken along line AA in FIGS. It is.

  As shown in FIGS. 1 to 3, the circuit protection component according to one embodiment of the present invention includes end electrodes 2 formed on both ends of the upper surface 1 a of the insulating substrate 1, and the upper surface 1 a of the insulating substrate 1. A fuse element 3 for connecting the end electrodes 2; first and second external electrodes 4a and 4b provided at both ends of the insulating substrate 1 and connected to the end electrode 2; Between the first, second, and third extraction electrodes 5a, 5b, and 5c formed on the back surface 1b facing the top surface 1a of the substrate 1, and between the first and second extraction electrodes 5a and 5b; An overvoltage protection material layer 6 made of metal powder and resin is provided so as to cover at least the space between the second extraction electrode 5b and the third extraction electrode 5c. The first extraction electrode 5a and the third extraction electrode 5c are connected to the first external electrode 4a and the second external electrode 4b, respectively, and the second extraction electrode 5b is connected to the insulating substrate 1. It is connected to the third external electrode 4c formed on the side surface.

  In the above configuration, the insulating substrate 1 has a square shape and is made of an insulating material such as ceramic.

  The end electrodes 2 are provided at both ends of the upper surface 1a, which is one surface of the insulating substrate 1, and are formed by printing Ag or the like.

  The fuse element 3 is formed by printing Ag or the like simultaneously with the end electrode 2 on the upper surface 1 a of the insulating substrate 1, and is provided in a straight line so as to connect the end electrodes 2. The fuse element 3 may be formed by a method such as plating or sputtering a metal such as Cu, Ni, or Ag separately from the end electrode 2.

  Also, the fuse element 3 is formed with a plurality of cuts 3 a, and the cuts 3 a are alternately provided from opposite side surfaces of the fuse element 3. Thereby, the current path flowing through the fuse element 3 can be meandered. With this configuration, since the inductance value of the fuse element 3 can be increased, the overvoltage that could not be released to the ground via the overvoltage protection material layer 6 can be removed by the fuse element 3, and thus the electronic device against the overvoltage can be removed. Can be more reliably protected. The shape of the fuse element 3 itself may be serpentine.

  Furthermore, a base layer having a lower thermal conductivity than the insulating substrate 1 may be provided between the fuse element 3 and the insulating substrate 1. And this fuse element 3 becomes an overcurrent protection part.

  The fuse element 3 (overcurrent protection unit) generates heat when an overcurrent is applied, and is melted and opened by the heat, thereby preventing further current from flowing.

  The first and second external electrodes 4 a and 4 b are provided at both ends of the insulating substrate 1 and are connected to the end electrodes 2, respectively. The third external electrode 4c is provided on one side of the insulating substrate 1 and one on the other side, and is connected to the second extraction electrode 5b. The first to third external electrodes 4a to 4c are made of a silver-based material, and a plating film (not shown) is formed on the surface thereof.

  The first, second, and third lead electrodes 5a, 5b, and 5c are made of metal such as Ni, Cu, Ag, Au, and Al on the back surface 1b that is the mounting surface facing the top surface 1a of the insulating substrate 1. It is formed by sputtering, vapor deposition or the like. Further, a gap 7 of 50 μm or less is formed between the first extraction electrode 5a and the second extraction electrode 5b and between the second extraction electrode 5b and the third extraction electrode 5c by etching, laser irradiation, etc. It is provided by the method.

  The first extraction electrode 5a is connected to the first external electrode 4a, and the third extraction electrode 5c is connected to the second external electrode 4b. Further, a part of the second extraction electrode 5b is exposed on both side surfaces of the insulating substrate 1 and connected to the third external electrode 4c.

  The overvoltage protection material layer 6 covers the gap 7 between the first extraction electrode 5a and the second extraction electrode 5b and the gap 7 between the second extraction electrode 5b and the third extraction electrode 5c. In addition, it is formed on a part of the first, second and third extraction electrodes 5a, 5b and 5c. The overvoltage protective material layer 6 has an average particle size of 0.3 to 10 μm, spherical metal powder made of Ni, Al, Ag, Pd, Cu or the like, a silicone resin such as methyl silicone, and a suitable organic solvent. The overvoltage protection material paste produced from the mixture with the above is formed by printing by a screen printing method. The overvoltage protection material layer 6 and the first, second, and third lead electrodes 5a, 5b, and 5c covered with the overvoltage protection material layer 6 are overvoltage protection portions.

  The overvoltage protection material layer 6 (overvoltage protection unit) normally has a high insulation resistance, so that no current flows. However, when an overvoltage is applied, the current flows and is bypassed to the ground.

  A protective film 8 made of epoxy resin, phenol resin or the like is formed so as to cover at least the fuse element 3 and the overvoltage protective material layer 6.

  Further, as shown in FIG. 4, one third external electrode 4c is formed on each of the two side surfaces of the circuit protection component body 9 obtained as described above, that is, the side surface of the insulating substrate 1, and The circuit protection component is provided at a position that is point-symmetric when viewed from above, and with such a configuration, the directionality during mounting is lost.

  As described above, in the embodiment of the present invention, the first extraction electrode 5a and the third extraction electrode 5c are connected to the first external electrode 4a and the second external electrode 4b, and the second extraction electrode is connected. Since the electrode 5b is connected to the third external electrode 4c formed on the side surface of the insulating substrate 1, the first and second external electrodes 4a and 4b are connected to the signal line, and the third external electrode 4c. By connecting to the ground, when an overvoltage is applied, the overvoltage can be released to the ground via the overvoltage protection material layer 6 to protect the electronic device, and when an overcurrent is applied, a fuse can be protected. The element 3 is opened and the electronic device can be protected, whereby the electronic device can be protected not only when an overvoltage but also an overcurrent is applied.

  That is, the circuit protection component according to the embodiment of the present invention is an equivalent circuit as shown in FIG. 5. In this circuit protection component, the first external electrode 4a and the second external electrode 4a both connected to the signal line are used. When an overcurrent is applied between the external electrode 4b and the fuse element 3, the fuse element 3 generates heat, blows and opens to protect the electronic device connected to the circuit protection component and the signal line. Yes.

  When an overvoltage is applied from the first external electrode 4a or the second external electrode 4b connected to the signal line, a discharge current flows between metal particles scattered in the overvoltage protection material layer 6, and this current Is bypassed to the ground via the third external electrode 4c, thereby protecting the electronic device connected to the circuit protection component and the signal line.

  Further, since two overvoltage protection units are formed, it is possible to suppress bidirectional overvoltage (overvoltage entering from the first external electrode 4a, overvoltage entering from the second external electrode 4b). For example, the circuit protection component of the present invention can suppress both an abnormal voltage that has entered from the outside and an electrostatic pulse that occurs when the human body and the terminal of the electronic device come in contact from the opposite direction. It becomes.

  In the circuit protection component according to the embodiment of the present invention, the fuse element 3 is formed on the upper surface (one surface) of the insulating substrate 1, and the overvoltage protection material layer 6 is formed on the rear surface (other surface) of the insulating substrate 1. However, the fuse element 3 may be formed on the back surface (other surface) of the insulating substrate 1 and the overvoltage protection material layer 6 may be formed on the upper surface (one surface) of the insulating substrate 1. The lower surface of the fuse element 3 is covered with the mounting board, and the gap between the mounting element and the mounting board is reduced. Furthermore, while heat has a property of escaping upward, the fuse element 3 is positioned downward, so that the escape path of heat generated in the fuse element 3 is reduced. As a result, since the heat dissipation of the heat generated in the fuse element 3 is deteriorated, the fuse element 3 can be blown quickly, and thus the electronic device can be more reliably protected.

  The circuit protection component according to the present invention has an effect that it is possible to protect an electronic device even when an overcurrent is applied as well as an overvoltage, and is particularly useful in a circuit protection component that protects an electronic device. It will be.

The top view of the principal part of the circuit protection component in one embodiment of this invention Rear view of the main part of the circuit protection component A-A line sectional view in FIGS. 1 and 2 Perspective view of the circuit protection component Equivalent circuit diagram of protective circuit parts

Explanation of symbols

1 Insulating substrate 1a One side (upper surface) of insulating substrate
1b The other side (back side) of the insulating substrate
2 end electrode 3 fuse element 4a-4c 1st-3rd external electrode 5a-5c 1st-3rd extraction electrode 6 overvoltage protection material layer

Claims (3)

End electrodes formed on both ends of one surface of the insulating substrate, fuse elements connecting the end electrodes on one surface of the insulating substrate, provided on both ends of the insulating substrate, and the end electrodes The connected first and second external electrodes, first, second and third extraction electrodes formed on the other surface opposite to one surface of the insulating substrate, the first extraction electrode and the second An overvoltage protection material layer made of metal powder and resin, and provided to cover at least between the extraction electrodes and between the second extraction electrode and the third extraction electrode, and the first An extraction electrode and a third extraction electrode are connected to the first external electrode and the second external electrode, respectively, and the second extraction electrode is connected to a third external electrode formed on a side surface of the insulating substrate. Circuit protection parts. A third external electrode is formed on one side of the insulating substrate and one on the other side, and the third external electrode is provided at a point-symmetrical position when the circuit protection component is viewed from above. The circuit protection component according to 1. 2. The circuit protection component according to claim 1, wherein a current path flowing through the fuse element is meandering.

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