JP2004087970A - Ptc composite chip component and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a surge protective circuit of a communication circuit by consolidating five components, which are the constituents in conventional methods, into one chip component. <P>SOLUTION: PTC thermistors 31 and 32, provided to one layer of the PTC composite chip component, are held between varistors 36, 39 provided to the upper layer thereof and varistors 37, 38 provided to a lower layer. Both ends of the PTC thermistors 31, 32 are each connected to external electrodes 61 to 64, provided radially facing side surfaces (side surfaces parallel to the page) of the PTC composite chip component. The varistors 36, 39 are connected by nickel 45, formed in the upper layer, the varistors 37, 38 are each connected to nickels 43, 44 formed in the lower layer, and the nickels 43, 44 are connected to external electrodes 65, 66 provided to radially facing side surfaces (side surfaces vertical to the page) of the PTC composite chip component. In the external electrodes 61 to 66, a PTC thermistor layer 67 is formed in a surface of an inner element, and a plated layer, such as silver, is formed thereon. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a PTC composite chip component, a method for manufacturing the same, and a surge protection circuit for a communication circuit using the PTC composite chip component, and more particularly to a PTC thermistor and a varistor for protecting the communication circuit from surges received via signal lines. The present invention relates to a PTC composite chip component, a method for manufacturing the same, and a surge protection circuit for a communication circuit.
[0002]
[Prior art]
In recent years, communication devices such as cellular phones and exchanges transmit and receive data in a wired or wireless manner or in a combination of both, in accordance with a standardized signal system by a communication LSI. An abnormal voltage (hereinafter, referred to as a surge) may be applied from the outside world, and the applied surge may enter a control board of a communication device through an electric wire and break an expensive LSI or the like. Since this communication LSI is an expensive and multi-pin QFP and cannot be easily replaced, it is necessary to protect against surges in the preceding stage, and a surge protection circuit is provided as a measure for this.
[0003]
FIG. 1 is a diagram showing a surge protection circuit of such a communication circuit.
[0004]
In FIG. 1, connector terminals 6 and 7 are connected to signal lines for transmitting and receiving signals to and from an external communication device. The connector terminals 6 and 7 are connected to a communication IC 9 via a transformer 8, and PTC thermistors 4 and 5 are provided between the connector terminals 6 and 7 and the transformer 8 respectively. Further, between the PTC thermistors 4 and 5, and the transformer 8, a circuit of the varistor 1 alone and a circuit composed of the varistors 2 and 3 in series are provided in parallel with the transformer 8, and the middle of the varistors 2 and 3 is grounded.
[0005]
A signal line connected to the connector terminals 6 and 7 is activated when the varistor 1 exceeds a preset varistor voltage with respect to a case where a surge causing a different voltage between the connector terminals 6 and 7 is applied. By reducing the potential difference between the two, the intrusion of a surge into the communication LSI 9 via the transformer 8 is prevented, and the destruction of the communication LSI 9 is prevented by reducing the surge potential to a level at which the communication LSI 9 is not destroyed. .
[0006]
Further, when a surge is applied and the connector terminals 6 and 7 greatly rise at the same potential, the varistors 2 and 3 act respectively to flow a large current to the ground when the voltage exceeds the varistor voltage. The potential of the signal line connected to 7 is lowered to prevent the transformer 8 from being destroyed. Further, an excessive current is prevented from being generated by the PTC thermistors 4 and 5. The line interface including the surge protection circuit is provided on the control board 50 together with other circuits.
[0007]
In the surge protection circuit of the conventional communication circuit, the varistors 1, 2, and 3 and the PTC thermistors 4 and 5 use individual components, and the printed wiring on the control board 50 connects these components to each other. Was composed.
[0008]
[Problems to be solved by the invention]
With the recent miniaturization of devices, the mounting of a plurality of communication lines on the same substrate has progressed, and the proportion occupied by the line interface has increased, so that the demand for miniaturization of the surge protection circuit described above has been increasing.
[0009]
However, in a conventional surge protection circuit of a communication circuit using individual components for each of the varistors 1, 2, and 3 and the PTC thermistors 4 and 5, there is a limit to miniaturization. This is because, when disposing single components at high density, it is necessary to provide a component interval of about 1 mm in order to avoid air discharge of surge, and there is a limit in reducing the mounting area.
[0010]
In view of the above, the present invention applies the multilayer technology used in multilayer ceramic capacitors and the like, and further provides a structure in which a PTC thermistor layer is provided on an external electrode, thereby satisfying the functions required in the past, while providing a conventional configuration. By combining the five parts that were used as parts into one chip part, the size of the surge protection circuit was reduced.
[0011]
[Means for Solving the Problems]
The PTC composite chip component according to the present invention includes first and second PTC thermistors (32, 31 in FIG. 2) provided so as to be insulated from each other in a first layer, so as to sandwich the first layer. The second and third layers provided, the first and second varistors (36 and 39 in FIG. 2) provided so as to be insulated from each other in the second layer, and the first varistor A third varistor (37 in FIG. 2) provided in the third layer so as to sandwich the first PTC thermistor, and the second varistor so as to sandwich the second PTC thermistor. A fourth varistor (38 in FIG. 2) provided so as to be insulated from the third varistor in the third layer, and a fourth varistor adjacent to the second layer opposite to the first layer; The first and second varistors provided in a fourth layer A first conductor (45 in FIG. 2) for conducting air and the third and fourth varistors provided on a fifth layer adjacent to the third layer on the opposite side of the first layer; Second and third conductors (43 and 44 in FIG. 2) that are electrically connected to a first external electrode (61 in FIG. 9) that is electrically connected to one end of the first PTC thermistor; A second external electrode (62 in FIG. 9) electrically connected to the other end of the first PTC thermistor and a third external electrode (FIG. 9) electrically connected to one end of the second PTC thermistor 63), a fourth external electrode (64 in FIG. 9) electrically connected to the other end of the second PTC thermistor, and a fifth external electrode (64 in FIG. 9) connected to the second conductor. 65) and a sixth external electrode (66 in FIG. 9) connected to the third conductor.
[0012]
The PTC composite chip component according to the present invention includes first and second PTC thermistors (32, 31 in FIG. 2) provided so as to be insulated from each other in a first layer, so as to sandwich the first layer. The second and third layers provided, the first and second varistors (36 and 39 in FIG. 2) provided so as to be insulated from each other in the second layer, and the first varistor A third varistor (37 in FIG. 2) provided in the third layer so as to sandwich the first PTC thermistor, and the second varistor so as to sandwich the second PTC thermistor. A fourth varistor (38 in FIG. 2) provided so as to be insulated from the third varistor in the third layer, and a fourth varistor adjacent to the second layer opposite to the first layer; The first and second varistors provided in a fourth layer A first conductor (45 in FIG. 2) for conducting air and the third and fourth varistors provided on a fifth layer adjacent to the third layer on the opposite side of the first layer; A plurality of composite layers having second and third conductors (43 and 44 in FIG. 2) electrically conductive to each other with an insulating layer interposed therebetween;
A first external electrode (61 in FIG. 9) electrically connected to one end of the first PTC thermistor and a second external electrode (FIG. 9) electrically connected to the other end of the first PTC thermistor 62), a third external electrode (63 in FIG. 9) electrically connected to one end of the second PTC thermistor, and a fourth external electrode electrically connected to the other end of the second PTC thermistor. An external electrode (64 in FIG. 9), a fifth external electrode (65 in FIG. 9) connected to the second conductor, and a sixth external electrode (66 in FIG. 9) connected to the third conductor. And characterized in that:
[0013]
In the above-mentioned PTC composite chip component, the planar shape of each layer including the first to fifth layers is rectangular, and these layers are stacked to form a rectangular parallelepiped as a whole, and the first and second PTC thermistors are provided. One end of each of the first and second PTC thermistors is located on a first side of the rectangular parallelepiped, and the other end of each of the first and second PTC thermistors is located on a second side opposite to the first side of the rectangular parallelepiped. The second conductor has an end on a third side between the first and second sides of the rectangular parallelepiped having the outer shape, and the third conductor has the third rectangular shape having the outer shape. An end is provided on a fourth side opposite to the side, at least a part of the first and third external electrodes is provided on the first side, and at least one of the second and fourth external electrodes is provided. Part is provided on the second side, and the fifth external part is provided. Provided at least partially the third aspect of the pole, at least part of the sixth external electrodes may be as provided in the fourth aspect.
[0014]
Further, in the above-described PTC composite chip component, all or a part of the first to sixth external electrodes may include a PTC thermistor layer (67 in FIG. 3). All or some of the external electrodes may include a PTC thermistor layer (67 in FIG. 3). In this case, the resistance value between the first external electrode and the second external electrode is such that the resistance value between the third external electrode and the fourth external electrode is equal. The thickness of the PTC thermistor layer can be adjusted in each of the first to fourth external electrodes provided with the thermistor layer. Further, the width of any one of the first to fourth external electrodes may be made different from the width of the other external electrodes so as to have a polar appearance.
[0015]
The method of manufacturing a PTC composite chip component described above includes forming an insulating layer by a green sheet forming technique, forming the first conductor on the insulating layer, and forming the first and second conductors on the first conductor. After the varistors are formed separately from each other, the first and second PTC thermistors are formed so as to overlap with the first and second varistors respectively, and the other parts than the first and second PTC thermistors are insulated. Forming a third body and a second PTC thermistor to form the third and fourth varistors on the first and second PTC thermistors; Manufactures
An insulating layer is interposed between the plurality of composite layers, and an insulating layer is also added to the entire upper surface, laminated and baked under pressure. An electrode is formed.
[0016]
The method of manufacturing the above-mentioned PTC composite chip component in which at least a part of the first to sixth external electrodes includes a PTC thermistor layer includes forming an insulating layer by a green sheet forming technique, and forming the insulating layer on the insulating layer. The first conductor is formed, and the first and second varistors are formed on the first conductor separately from each other, and the first and second varistors are respectively superimposed on the first and second varistors. A second PTC thermistor is formed, and an insulator is formed on a portion other than the first and second PTC thermistors to make an upper surface flat, and further, the third and the third PTC thermistors are superimposed on the third and second PTC thermistors. Forming a fourth varistor and forming the second and third conductors to produce a composite layer,
An insulating layer is interposed between the plurality of composite layers, and an insulating layer is also added to the entire upper surface, laminated and baked under pressure. At least a part of the electrode is formed including a PTC thermistor layer obtained by sputtering PTC ceramics containing barium titanate as a main component.
[0017]
In the method of manufacturing a PTC composite chip component described above, wherein at least a part of the first to sixth external electrodes includes a PTC thermistor layer, an insulating layer is formed by a green sheet forming technique. Forming the first conductor on a layer, forming the first and second varistors on the first conductor separately from each other, and superimposing the first and second varistors respectively on the first and second varistors; The first and second PTC thermistors are formed, and an insulator is formed on a portion other than the first and second PTC thermistors to make the upper surface flat, and the first and second PTC thermistors are further superimposed on the first and second PTC thermistors. Forming a third and fourth varistors and forming the second and third conductors to form a composite layer,
An insulating layer is interposed between the plurality of composite layers, and an insulating layer is also added to the entire upper surface, laminated and baked under pressure. At least a part of the electrode is formed including a PTC thermistor layer coated with a conductive polymer having PTC characteristics.
[0018]
A method of manufacturing the above-mentioned PTC composite chip component, wherein at least a part of the first to sixth external electrodes includes a PTC thermistor layer, an insulating layer is interposed between the plurality of composite layers, In addition, at the stage where the insulating layer is also added to the entire upper surface, baked under pressure, and the side surface is polished, the first PTC is formed without forming the first to sixth external electrodes on the side surface. The resistance between one end and the other end of the thermistor and the resistance between one end and the other end of the second PTC thermistor are measured. From the measurement result, the resistance between the first and second external electrodes is obtained. The PTC thermistor layers of the first to fourth external electrodes may be formed so as to have a thickness equal to the resistance value between the third and fourth external electrodes.
[0019]
The surge protection circuit of the communication circuit using the above-described PTC composite chip component connects first and second signal lines for transmitting and receiving signals to and from the outside to the first and third external electrodes, respectively. The transmission and reception first and second terminals of the circuit are connected to the second and fourth external electrodes, respectively, and the fifth and sixth external electrodes are grounded.
[0020]
The multilayer ceramic capacitor of the present invention is characterized in that the external electrode includes a PTC thermistor layer.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0022]
FIG. 2 is a cross-sectional view of the PTC composite chip component according to the embodiment of the present invention.
[0023]
In this PTC composite chip component, ceramics forming PTC thermistors 31 and 32 are formed in the same inner layer, ceramics forming varistors 36 (ZnO2) and 39 are formed on the upper layer, and varistors 37 and 38 are formed on the lower layer. The PTC thermistor 31 is sandwiched between varistors 38 and 39, and the PTC thermistor 32 is sandwiched between varistors 36 and 37. In these layers, portions other than the PTC thermistors 31 and 32 and the varistors 36 to 39 are filled with titanium oxide (TiO2) 46 as an insulator. Although not shown in FIG. 2, both ends of the PTC thermistors 31 and 32 reach opposite side surfaces of the PTC composite chip component (side surfaces parallel to the paper surface of FIG. 2, see FIG. 9).
[0024]
Further, the varistors 36 and 39 are electrically connected by a conductor made of nickel (Ni) 45 formed on the upper layer, and the varistors 37 and 38 are respectively connected to conductors made of nickel 43 and 44 formed on the lower layer. The ends of the nickels 43 and 44 are made to reach opposite side surfaces (side surfaces perpendicular to the plane of FIG. 2) of the PTC composite chip component. The nickels 43 and 44 are insulated from each other.
[0025]
PTC thermistors 31 and 32, varistors 36 to 39, and a plurality of composite layers composed of layers having nickels 43, 44 and 45 are laminated with a dummy ceramic layer composed of titanium oxide 48 interposed therebetween. Dummy ceramic layers made of titanium oxides 47 and 34 are formed in the lower layer, and external electrodes 61 to 66 (see FIG. 9) connected to both ends of the PTC thermistor 31 and both ends of the PTC thermistor 32 and nickels 43 and 44 are formed on side surfaces. are doing.
[0026]
The external electrodes 61 to 66 are formed by first forming a PTC thermistor layer 67 on the surface of the internal element and plating silver (Ag) or copper (Cu) and nickel thereon, as shown in a detailed partial sectional view in FIG. A layer 68 is formed, and a solder plating layer (Ni plating or Sn plating) 69 is formed on the outermost layer thereon.
[0027]
Next, a method for manufacturing the PTC composite chip component shown in FIGS. 2 and 3 will be described with reference to FIGS.
[0028]
This manufacturing method uses a green sheet forming technique for a multilayer ceramic capacitor. First, in order to form a titanium oxide 47 or 48 as a dummy layer, a plurality of titanium oxide green sheets are stacked as shown in FIG.
[0029]
Next, as shown in FIG. 5, a layer of nickel 45 is formed by screen printing on a portion of the laminated green sheet as titanium oxide 47 or 48 except for the peripheral portion, and varistors 36 and 39 are formed on the upper surface of the nickel 45. It is formed by screen printing separately from each other.
[0030]
Next, as shown in FIG. 6, PTC thermistors 32 and 31 are provided separately from each other on the laminate 80 shown in FIG. 5, and titanium oxide 46 is formed by screen printing on portions other than the PTC thermistors 32 and 31. In addition, the PTC thermistors 32 and 31 are formed so that both ends reach opposing edges of the laminate 80 so that the center portion is located on the varistors 36 and 39.
[0031]
Next, as shown in FIG. 7, the varistors 37 and 38 are separated from each other on the laminate 81 shown in FIG. 6 so as to be located on the PTC thermistors 32 and 31, but both ends of the laminate 80 are opposed to each other. It is formed so as not to reach the edge. Further, the nickels 43 and 44 are separated from each other, located on the varistors 37 and 38, and formed by protruding a part of the opposite side to the side of the laminate 81.
[0032]
Next, as shown in FIG. 8, a plurality of the laminates 82 shown in FIG. 7 and the titanium oxide 34 are laminated on the uppermost surface, then hot pressed and fired, and the side surfaces are polished to form internal elements. In addition, the titanium oxide 34 is obtained by laminating a plurality of green sheets similarly to the titanium oxide 47 shown in FIG. FIG. 2 shows a cross section A in FIG.
[0033]
External electrodes 61 to 66 are formed on the outer surfaces of the stacked and polished internal elements as shown in FIG. The external electrodes 61 to 66 may be formed by forming PTC ceramics containing barium titanate (BaTiO3) as a main component by sputtering or forming a conductive polymer having PTC characteristics on an end surface for leading out external electrodes after forming the internal elements. The PTC thermistor layer 67 is formed by coating, and an intermediate electrode is formed on the PTC thermistor layer 67 with a copper or silver plating layer 68, and an outermost electrode layer is formed with a nickel or tin solder plating layer 69.
[0034]
Note that the resistance value of the PTC thermistor 31 and the resistance value of the PTC thermistor 32 are not always the same and may differ due to manufacturing variations, but the resistance value of the PTC thermistor layer 67 of the external electrodes 61 to 64 may be different. And the resistance value of the PTC thermistor 31 or 32, that is, the resistance value between the external electrodes 61 and 62 or the resistance value between the external electrodes 63 and 64 (the corrected resistance value of the PTC thermistor 31 or 32) ) Can be the same so that the relative resistance value accuracy is within a predetermined range.
[0035]
That is, the resistance values of the PTC thermistors 31 and 32 are measured in advance with only the internal elements in which the external electrodes 61 to 64 have not been formed yet. To calculate the resistance value of the combination of the PTC thermistor layers 67 with the external electrodes 61 and 62 and the resistance value of the combination of the PTC thermistor layers 67 with the external electrodes 63 and 64, and further obtain these resistance values The total thickness of the PTC thermistor layer 67 with the external electrodes 61 and 62 and the total thickness of the PTC thermistor layer 67 with the external electrodes 63 and 64 are calculated. A layer 67 is formed.
[0036]
In this case, the ratio of the calculated total film pressure to the PTC thermistor layer 67 in the external electrodes 61 and 63 and the external electrodes 62 and 64 is arbitrary. For example, the external electrodes 61 and 62 may have the same thickness of the PTC thermistor layer 67, the external electrodes 63 and 64 may have the same thickness of the PTC thermistor layer 67, or the external electrodes 61 and 63 may have the same PTC thermistor layer. The PTC thermistor layer 67 may be omitted from the external electrodes 62 and 64.
[0037]
If the PTC composite chip parts shown in FIGS. 2 and 9 are applied to the surge protection circuit of the communication circuit shown in FIG. 1, the external electrodes 61 and 63 are connected to the connector terminals 6 and 7, respectively, and the external electrodes 62 and 64 are connected to the transformer. The external electrodes 65 and 66 are connected to two terminals for transmitting and receiving external signals. 1 and 2 by this connection, PTC thermistors 32 and 31 operate as PTC thermistors 4 and 5, varistors 37 and 38 operate as varistors 2 and 3, respectively, and varistors 36 and 39 operate as varistor 1 respectively. Relationship.
[0038]
FIG. 2 shows emission paths 40, 41 and 42 of the surge current. When a surge voltage is applied between the connector terminals 6 and 7 and a voltage exceeding the varistor voltage of the varistors 39 and 36 is applied between the PTC thermistors 31 and 32, a current flows as indicated by a path 42 and the potential between the PTC thermistors 31 and 32. Lower. On the other hand, when the surge is applied and the PTC thermistors 36 and 39 are overvoltage with respect to the ground at the same potential, the current from each is discharged to the ground through the paths 40 and 41, and the PTC thermistors 31 and 32 Lower the potential to ground.
[0039]
Further, when these two types of surge states continue for a long time, current also flows for a long time in the varistors 36 and 39 or the varistors 37 and 38 to generate heat. However, in the present embodiment, the PTC thermistors 31 and 32 are connected to the varistors 36 to 39. Since the trip temperature of the PTC thermistors 31 and 32 is set to a safe temperature, surge is applied before abnormal heat generation of the varistors 36 to 39 from the connector terminals 6 and 7 to the varistors 36 to 39. 39 can be shut off, and the communication IC 9 can also be shut off.
[0040]
Furthermore, a current blocking effect by the PTC thermistor layer 67 provided on the external electrodes 61 to 66 can be obtained, and the surge blocking performance can be improved.
[0041]
In addition, the external electrodes 61 to 66 having the PTC ceramic layer 67 can limit the current with respect to a short circuit caused by a micro crack or the like due to a mounting stress or a latent defect peculiar to the multilayer ceramic element. It is possible to prevent red heat ignition or the like of the PTC composite chip component due to electric current.
[0042]
Further, by adjusting the thickness of the PTC thermistor layer 67 of the external electrodes 61 to 64, the relative resistance value accuracy of the corrected resistance value of the PTC thermistors 31 and 32 can be kept within a predetermined range. The communication circuit provided with the protection circuit can be operated properly.
[0043]
Therefore, by using the PTC composite chip component of the present invention, there is obtained an effect that a surge protection circuit having a built-in varistor can be realized on a single chip without impairing the relative resistance value balance of the communication line.
[0044]
When it is necessary to change the thickness of the PTC thermistor layer 67 by the external electrodes 61 to 64 for the purpose of balancing the relative resistance value of the communication line, the external electrodes 61 to 64 are changed in width to change the external electrodes 61 to 64 in appearance. It can also be identified. For example, when the film thickness of the PTC thermistor layer 67 is changed between the external electrodes 61 and 62 in FIG. 9, the width of the external electrode 61 and the width of the external electrode 62 are set to 1: 2, and the polarity in appearance is changed. It is also possible to give.
[0045]
The resistance values of the PTC thermistor layers 31 and 32 can be changed by changing the frequency of overlapping the PTC thermistor layers 31 and 32 shown in FIG. 6, and the varistor voltage is changed by the varistors 36 to 36 shown in FIGS. This can be realized by changing the thickness of the 39 layers. The thickness of each layer and the repetition frequency of lamination shown in FIG. 2 may not be the same.
[0046]
As another embodiment of the present invention, by providing the PTC thermistor layer 67 as shown in FIG. 3 also on the external electrodes of the multilayer ceramic capacitor, it is possible to reduce the mounting stress of the multilayer ceramic capacitor and the micro-cracks due to potential defects. Even if a short circuit failure occurs, the PTC thermistor layer of the external electrode becomes a current limiting resistor, and it is possible to prevent a red heat ignition accident of the multilayer ceramic capacitor. In the multilayer ceramic capacitor, the PTC ceramic layers may be provided on both sides of the pair of external electrodes or only on one side. When the PTC thermistor layer is provided only on one side of the external electrode, the external electrodes provided with the PTC thermistor layer can be distinguished by giving a polarity in appearance by making the width of the two external electrodes 1: 2 or the like. it can.
[0047]
【The invention's effect】
The PTC composite chip component of the present invention can reduce the size of the surge protection circuit by integrating the first and second PTC thermistors and the first to fourth varistors constituting the surge protection circuit of the communication circuit in one chip. effective.
[0048]
Further, a PTC thermistor layer is provided on the external electrode, and the film thickness is adjusted to adjust the resistance of the first PTC thermistor and the first and second external electrodes connected to both ends of the first PTC thermistor and the second PTC thermistor. In addition, the third and fourth external electrodes connected to both ends thereof have the same resistance value and the relative resistance value accuracy is improved so that the PTC composite chip component is used for a surge protection circuit. The operation of the circuit can be properly maintained.
[0049]
In addition, by providing a PTC thermistor layer on an external electrode of a PTC composite chip component or a multilayer ceramic capacitor, current can be limited to a short circuit caused by a micro crack, and red heat ignition or the like can be prevented. .
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a surge protection circuit of a communication circuit.
FIG. 2 is a cross-sectional view of the PTC composite chip component according to the embodiment of the present invention.
FIG. 3 is a partially enlarged sectional view of an external electrode 65 in FIG.
FIG. 4 is a view showing the production of titanium oxide 47 of the PTC composite chip component shown in FIG.
FIG. 5 is a view showing the production of nickel 45 and varistors 36 and 39 of the PTC composite chip component shown in FIG. 2;
6 is a diagram showing the production of the PTC thermistors 32, 31 and titanium oxide 46 of the PTC composite chip component shown in FIG.
FIG. 7 is a view showing the production of varistors 37 and 38 and nickels 43 and 44 of the PTC composite chip component shown in FIG. 2;
FIG. 8 is a view showing the production of the PTC composite chip component shown in FIG. 2 in which a plurality of composite layers including the PTC thermistor layers 32 and 31 and varistors 36 to 39 shown in FIG. 7 are laminated.
FIG. 9 is a perspective view of the PTC composite chip component shown in FIG. 2;
[Explanation of symbols]
1 Varistor
2 Varistor
3 Varistor
4 PTC thermistor
5 PTC thermistor
6 Connector terminals
7 Connector terminal
8 transformer
9 Communication IC
31 PTC thermistor
32 PTC thermistor
34 Titanium oxide
36-39 Varistor
40-42 route
43-45 nickel
47 Titanium oxide
48 Titanium oxide
50 control board
61-66 External electrode
67 PTC thermistor layer
68 Plating layer
69 Solder plating layer
80-82 laminate

Claims (13)

First and second PTC thermistors provided so as to be insulated from each other in a first layer, second and third layers provided so as to sandwich the first layer, and the second layer A first and a second varistor provided so as to be insulated from each other, and a third varistor provided in the third layer so as to sandwich the first PTC thermistor with the first varistor. A fourth varistor provided so as to be insulated from the third varistor in the third layer so as to sandwich the second PTC thermistor between the second varistor and the second varistor; A first conductor provided on a fourth layer adjacent to the first layer opposite to the first layer and electrically connecting the first and second varistors; and a first conductor of the third layer. The fifth layer provided on the fifth layer adjacent to the opposite side of the layer. A second external conductor electrically connected to one end of the first PTC thermistor; a first external electrode electrically connected to one end of the first PTC thermistor; A second external electrode electrically connected to one end, a third external electrode electrically connected to one end of the second PTC thermistor, and an electrical connection to the other end of the second PTC thermistor A PTC composite chip component comprising: a fourth external electrode; a fifth external electrode connected to the second conductor; and a sixth external electrode connected to the third conductor. First and second PTC thermistors provided so as to be insulated from each other in a first layer, second and third layers provided so as to sandwich the first layer, and the second layer A first and a second varistor provided so as to be insulated from each other, and a third varistor provided in the third layer so as to sandwich the first PTC thermistor with the first varistor. A fourth varistor provided so as to be insulated from the third varistor in the third layer so as to sandwich the second PTC thermistor between the second varistor and the second varistor; A first conductor provided on a fourth layer adjacent to the first layer opposite to the first layer and electrically connecting the first and second varistors; and a first conductor of the third layer. The fifth layer provided on the fifth layer adjacent to the opposite side of the layer. And a plurality of composite layers superposed by an insulating layer interposed between them and a second and third conductor electrically connected to the respective fourth varistor,
A first external electrode electrically connected to one end of the first PTC thermistor; a second external electrode electrically connected to the other end of the first PTC thermistor; A third external electrode electrically connected to one end, a fourth external electrode electrically connected to the other end of the second PTC thermistor, and a fifth external electrode connected to the second conductor. And a sixth external electrode connected to the third conductor. The plane shape of each layer including the first to fifth layers is rectangular, and these layers are stacked to form a rectangular parallelepiped as a whole, and a rectangular parallelepiped in which one end of each of the first and second PTC thermistors forms a rectangular parallelepiped And the other end of each of the first and second PTC thermistors is located on a second side opposite to the first side of a rectangular parallelepiped having an outer shape, and the second conductor Has an end on a third side between the first and second sides of the cuboid having an outer shape, and the third conductor has a fourth side opposite to the third side of the cuboid having the outer shape. One end is provided on a side surface, at least a part of the first and third external electrodes is provided on the first side surface, and at least a part of the second and fourth external electrodes is provided on the second side surface. Wherein at least a part of the fifth external electrode is the third external electrode. Provided on the side, PTC composite chip component according to claim 1 or 2, at least a portion of said sixth external electrodes, characterized in that provided in the fourth aspect. 4. The PTC composite chip component according to claim 1, wherein all or a part of the first to sixth external electrodes includes a PTC thermistor layer. 5. 4. The PTC composite chip component according to claim 1, wherein all or a part of the first to fourth external electrodes includes a PTC thermistor layer. The thermistor layer is provided such that a resistance value between the first external electrode and the second external electrode is equal to a resistance value between the third external electrode and the fourth external electrode. 6. The PTC composite chip component according to claim 4, wherein a thickness of the PTC thermistor layer is adjusted in each of the first to fourth external electrodes. 7. The PTC composite chip component according to claim 6, wherein the width of any one of the first to fourth external electrodes is made different from the width of the other external electrodes so as to have polarities in appearance. Forming an insulating layer by a green sheet forming technique, forming the first conductor on the insulating layer, and forming the first and second varistors on the first conductor separately from each other, The first and second PTC thermistors are formed so as to overlap the first and second varistors, respectively, and an insulator is formed in a portion other than the first and second PTC thermistors to form a flat upper surface, and Forming a composite layer by forming the second and third conductors on the third and fourth varistors on the first and second PTC thermistors;
An insulating layer is interposed between the plurality of composite layers, and an insulating layer is also added to the entire upper surface, laminated and baked under pressure. The method for manufacturing a PTC composite chip component according to claim 1, wherein an electrode is formed. Forming an insulating layer by a green sheet forming technique, forming the first conductor on the insulating layer, and forming the first and second varistors on the first conductor separately from each other, The first and second PTC thermistors are formed so as to overlap the first and second varistors, respectively, and an insulator is formed in a portion other than the first and second PTC thermistors to form a flat upper surface, and Forming a composite layer by forming the second and third conductors on the third and fourth varistors on the first and second PTC thermistors;
An insulating layer is interposed between the plurality of composite layers, and an insulating layer is also added to the entire upper surface, laminated and baked under pressure. The PTC composite chip component according to any one of claims 4 to 7, wherein the electrode is formed at least partially including a PTC thermistor layer obtained by sputtering PTC ceramics containing barium titanate as a main component. Method. Forming an insulating layer by a green sheet forming technique, forming the first conductor on the insulating layer, and forming the first and second varistors on the first conductor separately from each other, The first and second PTC thermistors are formed so as to overlap the first and second varistors, respectively, and an insulator is formed in a portion other than the first and second PTC thermistors to form a flat upper surface, and Forming a composite layer by forming the second and third conductors on the third and fourth varistors on the first and second PTC thermistors;
An insulating layer is interposed between the plurality of composite layers, and an insulating layer is also added to the entire upper surface, laminated and baked under pressure. The method for manufacturing a PTC composite chip component according to any one of claims 4 to 7, wherein at least a part of the electrode is formed including a PTC thermistor layer coated with a conductive polymer having PTC characteristics. An insulating layer is interposed between the plurality of composite layers, and an insulating layer is also added to the entire upper surface, laminated and baked under pressure. The resistance between one end and the other end of the first PTC thermistor and the resistance between one end and the other end of the second PTC thermistor are measured in a state where no external electrode is formed. As a result, the PTC thermistor layer of the first to fourth external electrodes has a thickness such that the resistance between the first and second external electrodes is equal to the resistance between the third and fourth external electrodes. The method of manufacturing a PTC composite chip component according to claim 9, wherein: First and second signal lines for transmitting and receiving signals to the outside are respectively connected to the first and third external electrodes, and first and second terminals for transmission and reception of a communication circuit are respectively connected to the second terminal. 8. A surge protection circuit for a communication circuit using a PTC composite chip component according to claim 1, wherein said surge protection circuit is connected to said first and fourth external electrodes, and said fifth and sixth external electrodes are grounded. A multilayer ceramic capacitor comprising a PTC thermistor layer in an external electrode.

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