Transient voltage protection component and mounting structure for the transient voltage protection component

Abstract

To provide a transient voltage protection component that can enhance transient voltage protection characteristics.SOLUTION: A transient voltage protection component 1 includes coil components 9, varistor components 10, a first terminal electrode 3, and a second terminal electrode 4. The coil components 9 and the varistor components 10 are connected in parallel between the first terminal electrode 3 and the second terminal electrode 4. The coil component 9 is configured to magnetically saturate when a voltage higher than a predetermined voltage is applied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to transient voltage protection components. [Background technology]

[0002] BACKGROUND ART In electronic circuits including semiconductors and the like, varistors are used to protect elements from various surges (transient voltages) such as electrostatic discharge (ESD) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-267713 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of one aspect of the present invention is to provide a transient voltage protection component and a mounting structure for the transient voltage protection component that can improve transient voltage protection characteristics. [Means for solving the problem]

[0005] A transient voltage protection component according to one aspect of the present invention comprises a coil portion, a first transient voltage protection portion, a first electrode, and a second electrode, the coil portion and the first transient voltage protection portion being connected in parallel between the first electrode and the second electrode, and the coil portion being configured to become magnetically saturated when a voltage higher than a predetermined voltage is applied.

[0006] A transient voltage protection component according to one aspect of the present invention includes a coil configured to be magnetically saturated when a voltage higher than a predetermined voltage is applied. The coil has high resistance (impedance) to signals with high frequency components, but becomes magnetically saturated when subjected to a large voltage (load) such as ESD. When magnetic saturation occurs in the coil, the resistance becomes low, allowing current to flow. Therefore, the transient voltage protection circuit can release large voltages such as ESD to ground. This reduces the clamp voltage in the transient voltage protection component. Furthermore, since the transient voltage protection circuit includes a coil and a first transient voltage protection unit, energy due to ESD or the like can be distributed between the coil and the first transient voltage protection unit. Therefore, the transient voltage protection circuit can improve its tolerance to transient voltages. As a result, the transient voltage protection circuit can improve its transient voltage protection characteristics.

[0007] In one embodiment, the predetermined voltage may be equal to or lower than the operating voltage at which the first transient voltage protection unit operates. In this configuration, magnetic saturation can be generated in the coil unit before the first transient voltage protection unit operates.

[0008] In one embodiment, each of the coil portion and the first transient voltage protection portion is a chip component, and includes a base portion on which the first electrode and the second electrode are arranged, a first land electrode arranged on the base and connected to the first electrode, a second land electrode arranged on the base and connected to the second electrode, and a sealing portion that seals the coil portion and the first transient voltage protection portion, and the coil portion and the first transient voltage protection portion may be connected to the first land electrode and the second land electrode, respectively. With this configuration, the transient voltage protection component can be configured as a single component.

[0009] In one embodiment, the distance between the coil section and the transient voltage protection section may be smaller than the distance between the first land electrode and the second land electrode. This configuration can reduce the parasitic inductance generated between the coil section and the transient voltage protection section, thereby improving the characteristics (S parameters).

[0010] In one embodiment, the coil portion and the first transient voltage protection portion may each be a chip component, and the coil portion and the first transient voltage protection portion may be joined by a joint made of resin. In this configuration, the linear expansion of the coil portion and the varistor component 22 can be absorbed by the joint. This can improve the thermal characteristics.

[0011] In one embodiment, the transient voltage protection component may include an element body on which the first electrode and the second electrode are respectively disposed, and the coil portion and the first transient voltage protection portion are disposed within the element body. In this configuration, the transient voltage protection component can be configured as a single component.

[0012] In one embodiment, the current-voltage characteristic may switch at a first threshold voltage and also switch at a second threshold voltage that is lower than the first threshold voltage.

[0013] In one embodiment, a second transient voltage protection unit is provided, and the first transient voltage protection unit, the coil unit, and the second transient voltage protection unit are connected in parallel between the first electrode and the second electrode, and the coil unit and the second transient voltage protection unit may be connected in series in this order from the first electrode side. This configuration further improves resistance to transient voltages.

[0014] In one embodiment, the magnetic saturation voltage at which the coil section is magnetically saturated may be lower than the operating voltage at which the first transient voltage protection section operates. In this configuration, magnetic saturation can be generated in the coil section before the first transient voltage protection section operates.

[0015] A mounting structure for a transient voltage protection component according to one aspect of the present invention is the mounting structure for the transient voltage protection circuit described above, in which the first electrode is connected to a signal line and the second electrode is connected to ground.

[0016] In a mounting structure for a transient voltage protection component according to one aspect of the present invention, the transient voltage protection component includes a coil. The coil has high resistance (impedance) to signals with high frequency components, but undergoes magnetic saturation when subjected to a large voltage (load) such as ESD. When magnetic saturation occurs in the coil, the resistance becomes low, allowing current to flow. Therefore, the mounting structure for the transient voltage protection component can dissipate large voltages, such as ESD, input to the signal line to ground. This reduces the clamp voltage. Furthermore, since the transient voltage protection component includes a coil and a first transient voltage protection unit, energy due to ESD or the like can be distributed between the coil and the first transient voltage protection unit. Therefore, the mounting structure for the transient voltage protection component improves resistance to transient voltages. As a result, the mounting structure for the transient voltage protection component improves transient voltage protection characteristics. [Effects of the Invention]

[0017] According to one aspect of the present invention, transient voltage protection characteristics can be improved. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view of a transient voltage protection component according to a first embodiment. [Figure 2] 2(a) is a cross-sectional view taken along line aa in FIG. 1, and FIG. 2(b) is a cross-sectional view taken along line bb in FIG. [Figure 3] FIG. 3 is a circuit diagram of the transient voltage protection component shown in FIG. [Figure 4] FIG. 4 is a diagram showing an example of the current-voltage characteristics of a coil and a varistor. [Figure 5] FIG. 5 is a diagram showing the current-voltage characteristics of the transient voltage protection circuit shown in FIG. [Figure 6] FIG. 6 is a diagram showing a clamp waveform. [Figure 7] FIG. 7 is a perspective view of a transient voltage protection component according to the second embodiment. [Figure 8]FIG. 8 is a cross-sectional view of the transient voltage protection component shown in FIG. [Figure 9] FIG. 9 is a circuit diagram of the transient voltage protection component shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view of a transient voltage protection component according to the third embodiment. [Figure 11] FIG. 11 is a circuit diagram of the transient voltage protection component shown in FIG. [Figure 12] FIG. 12 is a diagram showing the current-voltage characteristics of the transient voltage protection circuit shown in FIG. [Figure 13] FIG. 13 is a perspective view of a transient voltage protection component according to the fourth embodiment. [Figure 14] FIG. 14 is an exploded perspective view of the transient voltage protection component shown in FIG. [Figure 15] FIG. 15 is a circuit diagram of the transient voltage protection component shown in FIG. [Figure 16] FIG. 16 is a perspective view of a transient voltage protection component according to the fifth embodiment. [Figure 17] FIG. 17 is a side view of the transient voltage protection component shown in FIG. [Figure 18] FIG. 18 is a top view of the transient voltage protection component shown in FIG. [Figure 19] FIG. 19 is an end view of the transient voltage protection component shown in FIG. [Figure 20] FIG. 20 is a circuit diagram of the transient voltage protection component shown in FIG. [Figure 21] FIG. 21 is a diagram showing current-voltage characteristics of the transient voltage protection circuit according to the modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and redundant description will be omitted.

[0020] [First embodiment] Fig. 1 is a diagram showing a transient voltage protection component 1 according to a first embodiment. As shown in Fig. 1, the transient voltage protection component 1 includes a base 2, a first terminal electrode (first electrode) 3, a second terminal electrode (second electrode) 4, a first land electrode 5, a second land electrode 6, a third land electrode (first land electrode) 7, a fourth land electrode (second land electrode) 8, a coil component (coil portion) 9, a varistor component (first transient voltage protection portion) 10, and a sealing portion 11. For ease of explanation, an X direction and a Y direction are defined in Fig. 1.

[0021] The base 2 has a substantially rectangular parallelepiped shape. The base 2 is, for example, a PCB (Printed Circuit Board). The base 2 has a first main surface 2a, a second main surface 2b facing the first main surface 2a, and a side surface 2c connecting the first main surface 2a and the second main surface 2b.

[0022] The first terminal electrode 3 is disposed across the second main surface 2b of the base 2 and one side surface 2c in the X direction. As shown in FIGS. 2(a) and 2(b), the first terminal electrode 3 has an L-shape. The first terminal electrode 3 is made of a conductive material (for example, Ni or Cu). The first terminal electrode 3 may be disposed only on the second main surface 2b of the base 2.

[0023] The second terminal electrode 4 is disposed across the second main surface 2b of the base 2 and the other side surface 2c in the X direction. The second terminal electrode 4 is disposed spaced apart from the first terminal electrode 3 in the X direction. The second terminal electrode 4 is L-shaped and made of a conductive material (for example, Ni or Cu). The second terminal electrode 4 may be disposed only on the second main surface 2b of the base 2.

[0024] The first land electrode 5 is disposed on the first main surface 2a of the base 2. The first land electrode 5 is electrically connected to the first terminal electrode 3 by a connecting conductor 12. The second land electrode 6 is disposed on the first main surface 2a of the base 2. The second land electrode 6 is electrically connected to the second terminal electrode 4 by a connecting conductor 13. The first land electrode 5 and the second land electrode 6 are disposed at a predetermined interval in the X direction.

[0025] The third land electrode 7 is disposed on the first main surface 2a of the base 2. The third land electrode 7 is electrically connected to the first terminal electrode 3 by a connecting conductor 14. The fourth land electrode 8 is disposed on the first main surface 2a of the base 2. The fourth land electrode 8 is electrically connected to the second terminal electrode 4 by a connecting conductor 15. The third land electrode 7 and the fourth land electrode 8 are disposed at a predetermined interval in the X direction. The first land electrode 5 and the third land electrode 7 are disposed at a predetermined interval in the Y direction. The second land electrode 6 and the fourth land electrode 8 are disposed at a predetermined interval in the Y direction.

[0026] Fig. 2(b) is a cross-sectional view taken along line bb in Fig. 1. As shown in Fig. 2(b), the coil component 9 includes an element body 9a, a first external electrode 9b, a second external electrode 9c, and a coil 9d. The coil component 9 is a chip component.

[0027] The element body 9a has a rectangular parallelepiped shape. The element body 9a is configured by stacking multiple dielectric layers. Each dielectric layer is configured, for example, from a magnetic material. The magnetic material includes, for example, at least one selected from a Ni-Cu-Zn ferrite material, a Ni-Cu-Zn-Mg ferrite material, and a Ni-Cu ferrite material. The magnetic material configuring the element body 9a may include an Fe alloy or the like. The element body 9a may be configured from a non-magnetic material. The non-magnetic material includes, for example, at least one selected from a glass ceramic material and a dielectric material.

[0028] The first external electrode 9b is disposed on one end surface of the element body 9a. The second external electrode 9c is disposed on the other end surface of the element body 9a. The first external electrode 9b and the second external electrode 9c are made of a conductive material (such as Ni or Cu).

[0029] Coil 9d is disposed within element body 9a. Coil 9d is configured by connecting multiple coil conductors. The multiple coil conductors are made of a conductive material (such as Ni or Cu) that is typically used as a coil conductor.

[0030] The coil component 9 is disposed on the third land electrode 7 and the fourth land electrode 8. Specifically, the first external electrode 9b of the coil component 9 is disposed on the third land electrode 7, and the second external electrode 9c of the coil component 9 is disposed on the fourth land electrode 8. The first external electrode 9b and the third land electrode 7 are joined by solder H. As a result, the first external electrode 9b is electrically connected to the first terminal electrode 3. The second external electrode 9c and the fourth land electrode 8 are joined by solder H. As a result, the second external electrode 9c is electrically connected to the second terminal electrode 4.

[0031] Fig. 2(a) is a cross-sectional view taken along line aa in Fig. 1. As shown in Fig. 2(a), the varistor component 10 comprises an element body 10a, a first external electrode 10b, a second external electrode 10c, and an internal electrode 10d. The varistor component 10 is a chip component.

[0032] The element body 10a has a rectangular parallelepiped shape. The element body 10a is configured by stacking multiple dielectric layers. Each dielectric layer may contain, for example, zinc oxide (ZnO) as a main component, and may also contain, as secondary components, elemental metals such as Co, rare earth metal elements, group IIIb elements (B, Al, Ga, In), Si, Cr, Mo, alkali metal elements (K, Rb, Cs), and alkaline earth metal elements (Mg, Ca, Sr, Ba), as well as oxides of these metals.

[0033] The first external electrode 10b is disposed on one end surface of the element body 10a. The second external electrode 10c is disposed on the other end surface of the element body 10a. The first external electrode 10b and the second external electrode 10c are made of a conductive material (such as Ni or Cu).

[0034] The internal electrode 10d is disposed within the element body 10a. Two internal electrodes 10d are disposed. One internal electrode 10d is connected to the first external electrode 10b. The other internal electrode 10d is connected to the second external electrode 10c. The internal electrodes 10d are made of a conductive material (for example, Ni or Cu).

[0035] The varistor component 10 is arranged on the first land electrode 5 and the second land electrode 6. Specifically, the first external electrode 10b of the varistor component 10 is arranged on the first land electrode 5, and the second external electrode 10c of the varistor component 10 is arranged on the second land electrode 6. The first external electrode 10b and the first land electrode 5 are joined by solder H. As a result, the first external electrode 10b is electrically connected to the first terminal electrode 3. The second external electrode 10c and the second land electrode 6 are joined by solder H. As a result, the second external electrode 10c is electrically connected to the second terminal electrode 4.

[0036] The first land electrode 5 and the third land electrode 7 may be one member. That is, the first external electrode 9b of the coil component 9 and the first external electrode 10b of the varistor component 10 may be arranged on one land electrode. The second land electrode 6 and the fourth land electrode 8 may be one member. That is, the second external electrode 9c of the coil component 9 and the second external electrode 10c of the varistor component 10 may be arranged on one land electrode.

[0037] As shown in Fig. 1, the sealing portion 11 covers the coil component 9 and the varistor component 10. The sealing portion 11 has a rectangular parallelepiped shape. The sealing portion 11 is made of resin. The sealing portion 11 is provided to protect the coil component 9 and the varistor component 10. The sealing portion 11 has the functions of suppressing the application of external forces to the coil component 9 and the varistor component 10, electrically insulating the coil component 9 and the varistor component 10 from the outside, and protecting the coil component 9 and the varistor component 10 from dust, dirt, etc.

[0038] In the transient voltage protection component 1, the varistor component 10 and the coil component 9 are electrically connected in parallel between the first terminal electrode 3 and the second terminal electrode 4. In the transient voltage protection component 1, the distance G1 (see FIG. 1) between the coil component 9 and the varistor component 10 in the Y direction is smaller than the distance G2 (see FIG. 2(a)) between the first land electrode 5 (third land electrode 7) and the second land electrode 6 (fourth land electrode 8) in the X direction.

[0039] FIG. 3 is a circuit diagram of the transient voltage protection component 1 shown in FIG. 1. As shown in FIG. 3, the transient voltage protection component 1 is connected between a signal line L1 and a ground line L2. The transient voltage protection component 1 has a first terminal electrode 3 connected to the signal line L1 and a second terminal electrode 4 connected to the ground line L2. That is, the transient voltage protection component 1 is mounted so that the first terminal electrode 3 is connected to the signal line L1 and the second terminal electrode 4 is connected to the ground line L2. That is, FIG. 3 shows the mounting structure of the transient voltage protection component 1. The transient voltage protection component 1 is a circuit for protecting a device to be protected (e.g., an integrated circuit (IC)) when a large voltage (surge voltage) flows into the signal line L1 due to ESD or the like. The signal line L1 is connected to the device to be protected. The ground line L2 is connected to ground G.

[0040] The coil component 9 and the varistor component 10 of the transient voltage protection component 1 are electrically connected in parallel between the signal line L1 and the ground line L2.

[0041] The coil component 9 is configured to be magnetically saturated when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is a magnetic saturation voltage, which is a voltage higher than the maximum value of the signal voltage flowing through the signal line L1. The signal voltage is the voltage of a control signal or the like flowing through the signal line L1.

[0042] The varistor component 10 is configured to operate when a predetermined voltage or higher is applied. The predetermined voltage is the varistor voltage (operating voltage). The varistor voltage can also be said to be the breakdown voltage.

[0043] In the transient voltage protection component 1, the magnetic saturation voltage at which the coil component 9 becomes magnetically saturated is equal to or lower than the varistor voltage at which the varistor component 10 operates (magnetic saturation voltage≦varistor voltage). In this embodiment, the magnetic saturation voltage is lower than the varistor voltage. In this configuration, in the transient voltage protection component 1, magnetic saturation of the coil component 9 occurs before operation of the varistor component 10.

[0044] FIG. 4 is a diagram showing an example of the current-voltage characteristics of the coil component 9 and the varistor component 10. In FIG. 4, the horizontal axis represents voltage (V) and the vertical axis represents current (A). In FIG. 4, the characteristics of the coil component 9 are shown by a solid line, and the characteristics of the varistor component 10 are shown by a dashed line. As shown in FIG. 4, the coil component 9 undergoes snapback operation (the snapback phenomenon occurs) at a magnetic saturation voltage (snapback voltage), resulting in magnetic saturation. In other words, it can be said that the coil component 9 exhibits snapback operation. When magnetic saturation occurs in the coil component 9, the resistance becomes low and current flows. The varistor component 10 breaks down when the voltage exceeds the varistor voltage. When the voltage exceeds the varistor voltage, the resistance becomes low and current flows in the varistor component 10.

[0045] Fig. 5 is a diagram showing the current-voltage characteristics of the transient voltage protection component 1. In Fig. 5, the horizontal axis represents voltage (V) and the vertical axis represents current (A). Fig. 5 shows the results of TLP (Transmission Line Pulse) measurement.

[0046] As shown in FIG. 5, the current-voltage characteristics (current-voltage characteristics) of the transient voltage protection component 1 have two switching points (hereinafter referred to as "switching points") where the characteristic (impedance) switches. The switching points are the starting points for major changes in the graph of the current-voltage characteristics. In the transient voltage protection component 1, a first switching point occurs at a first threshold voltage V1, and current flows. After the first switching point, the current flows more than before. The slope of the graph after the first switching point is steeper than the slope up to the first switching point. Next, in the transient voltage protection component 1, a second switching point occurs at a second threshold voltage V2. As a result, the transient voltage protection component 1 becomes low-resistance, and further current flows. The slope of the graph after the second switching point is steeper than the slope from the first switching point to the second switching point. Between the first switching point (first threshold voltage V1) and the second switching point (second threshold voltage V2), the resistance gradually decreases over a certain time period (current gradually flows). The first threshold voltage V1 is greater than the second threshold voltage V2. The first threshold voltage V1 is greater than the signal voltage. The first threshold voltage V1 can also be said to be a magnetic saturation voltage.

[0047] As described above, the transient voltage protection component 1 according to this embodiment includes the coil component 9. The coil component 9 has high resistance (impedance) to signals with high frequency components, but undergoes magnetic saturation when subjected to a large voltage (load) such as ESD. When magnetic saturation occurs in the coil component 9, the resistance becomes low, allowing current to flow. Therefore, the transient voltage protection component 1 can release a large voltage such as ESD input to the signal line L1 to the ground line L2 (ground G). This allows the transient voltage protection component 1 to reduce the clamping voltage.

[0048] Fig. 6 is a diagram showing clamp characteristics. In Fig. 6, the horizontal axis represents time (ns) and the vertical axis represents voltage (V). In Fig. 6, the measurement results for the coil component 9 are shown by a dashed line, the measurement results for the varistor component 10 are shown by a broken line, and the measurement results for the transient voltage protection component 1 are shown by a solid line. Fig. 6 shows the measurement results (waveform) when a predetermined ESD waveform is applied using an ESD gun.

[0049] As shown in FIG. 6, when a voltage is applied to the coil component 9, the peak voltage value (for example, about 1800 V) is high immediately after application, but the voltage drops immediately after the peak. The average voltage value over time is low for the coil component 9. When a voltage is applied to the varistor component 10, the peak voltage value (for example, about 800 V) immediately after application is lower than that of the coil component 9, but the voltage remains high even after the peak. The average voltage value over time for the coil component 9 is higher than that of the coil component 9. When a voltage is applied to the transient voltage protection component 1, the peak voltage value can be suppressed immediately after application, while the average voltage value over time can be lowered. The transient voltage protection component 1 has clamping characteristics that make use of the advantages of the clamping characteristics of the coil component 9 and the varistor component 10.

[0050] Furthermore, since the transient voltage protection component 1 includes the coil component 9 and the varistor component 10, energy from ESD and the like can be distributed between the coil component 9 and the varistor component 10. This improves the transient voltage resistance of the transient voltage protection component 1. This improves the transient voltage protection characteristics of the transient voltage protection component 1.

[0051] In the transient voltage protection component 1 according to this embodiment, the coil component 9 and the varistor component 10 are each chip components. The transient voltage protection component 1 includes a base portion 2 on which a first terminal electrode 3 and a second terminal electrode 4 are arranged, a first land electrode 5 and a third land electrode 7 arranged on the base portion 2 and connected to the first terminal electrode 3, a second land electrode 6 and a fourth land electrode 8 arranged on the base portion 2 and connected to the second terminal electrode 4, and a sealing portion 11 that seals the coil component 9 and the varistor component 10. The coil component 9 is connected to the third land electrode 7 and the fourth land electrode 8, respectively, and the varistor component 10 is connected to the first land electrode 5 and the second land electrode 6, respectively. This configuration allows the transient voltage protection component 1 to be configured as a single component. Therefore, the transient voltage protection component 1 can be miniaturized while improving its transient voltage protection characteristics.

[0052] In the transient voltage protection component 1 according to this embodiment, the coil component 9 becomes magnetically saturated when a voltage higher than the signal voltage of the signal line L1 is applied. The magnetic saturation voltage at which the coil component 9 becomes magnetically saturated is lower than the varistor voltage of the varistor component 10. In this configuration, magnetic saturation can be generated in the coil component 9 before the varistor component 10 operates.

[0053] In the transient voltage protection component 1 according to this embodiment, the S parameter can be controlled by matching the inductance of the coil component 9 with the capacitance of the varistor component 10. Therefore, in the transient voltage protection component 1, desired impedance characteristics can be obtained by appropriately matching the inductance of the coil component 9 with the capacitance of the varistor component 10. This allows the transient voltage protection component 1 to have a low capacitance.

[0054] As shown in FIG. 5, the transient voltage protection component 1 according to this embodiment has a switching portion at the first threshold voltage V1 and a switching portion at the second threshold voltage V2 in the current-voltage characteristic. Between the first threshold voltage V1 and the second threshold voltage V2, the waveform continues to gradually decrease in resistance. Therefore, a sudden current does not flow to ground G between the first threshold voltage V1 and the second threshold voltage V2. This prevents deviations in the reference potential of ground G.

[0055] In the transient voltage protection component 1 according to this embodiment, the distance G1 (see FIG. 1) between the coil component 9 and the varistor component 10 is smaller than the distance G2 (see FIG. 2(a)) between the first land electrode 5 (third land electrode 7) and the second land electrode 6 (fourth land electrode 8). With this configuration, the parasitic inductance generated between the coil component 9 and the varistor component 10 can be reduced, thereby improving the characteristics (S parameters).

[0056] [Second embodiment] Next, a second embodiment will be described. Fig. 7 is a diagram showing a transient voltage protection component according to the second embodiment. As shown in Fig. 7, a transient voltage protection component 20 includes a coil component (coil portion) 21, a varistor component (first transient voltage protection portion) 22, a first external electrode (first electrode) 23, and a second external electrode (second electrode) 24.

[0057] Fig. 8 is a cross-sectional view of the transient voltage protection component 20 shown in Fig. 7. As shown in Fig. 8, the coil component 21 includes an element body 21a, a first external electrode 21b, a second external electrode 21c, and a coil 21d. The coil component 21 is a ferrite bead.

[0058] The element body 21a has a rectangular parallelepiped shape. The element body 21a is configured by stacking a plurality of dielectric layers. Each dielectric layer is configured, for example, from a magnetic material. The magnetic material includes, for example, at least one selected from a Ni-Cu-Zn ferrite material, a Ni-Cu-Zn-Mg ferrite material, and a Ni-Cu ferrite material. The magnetic material configuring the element body 21a may include an Fe alloy or the like. The element body 21a may be configured from a non-magnetic material. The non-magnetic material includes, for example, at least one selected from a glass ceramic material and a dielectric material.

[0059] The first external electrode 21b is disposed on one end surface of the element body 21a. The second external electrode 21c is disposed on the other end surface of the element body 21a. The first external electrode 21b and the second external electrode 21c are fired electrodes and made of a conductive material (for example, Ni or Cu).

[0060] Coil 21d is disposed within element body 21a. Coil 21d is configured by connecting multiple coil conductors. The multiple coil conductors are made of a conductive material (such as Ni or Cu) that is typically used as a coil conductor.

[0061] The varistor component 22 comprises an element body 22a, a first external electrode 22b, a second external electrode 22c, and an internal electrode 22d.

[0062] The element body 22a has a rectangular parallelepiped shape. The element body 22a is configured by laminating multiple dielectric layers. Each dielectric layer may contain, for example, zinc oxide (ZnO) as a main component, and may also contain, as secondary components, elemental metals such as Co, rare earth metal elements, group IIIb elements (B, Al, Ga, In), Si, Cr, Mo, alkali metal elements (K, Rb, Cs), and alkaline earth metal elements (Mg, Ca, Sr, Ba), as well as oxides of these metals.

[0063] The first external electrode 22b is disposed on one end surface of the element body 22a. The second external electrode 22c is disposed on the other end surface of the element body 22a. The first external electrode 22b and the second external electrode 22c are fired electrodes and made of a conductive material (for example, Ni or Cu).

[0064] The internal electrode 22d is disposed within the element body 22a. Two internal electrodes 22d are disposed. One of the internal electrodes 22d is connected to the first external electrode 22b. The other internal electrode 22d is connected to the second external electrode 22c. The two internal electrodes 22d are disposed opposite each other. The internal electrodes 22d are made of a conductive material (for example, Ni or Cu).

[0065] The first external electrode 23 is connected to the first external electrode 21b of the coil component 21 and the first external electrode 22b of the varistor component 22. The first external electrode 21b and the first external electrode 22b are in contact with each other, and the first external electrode 23 is formed so as to cover the first external electrode 21b and the first external electrode 22b.

[0066] The second external electrode 24 is connected to the second external electrode 21c of the coil component 21 and the second external electrode 22c of the varistor component 22. The second external electrode 21c and the second external electrode 22c are in contact with each other, and the second external electrode 24 is formed so as to cover the second external electrodes 21c and 22c. The first external electrode 23 and the second external electrode 24 are platings (plating layers) formed by, for example, electrolytic plating or electroless plating, and made of a conductive material (for example, Ni or Cu).

[0067] The coil component 21 and the varistor component 22 are joined by a joint 25. The joint 25 fills a space formed by the first external electrode 21b of the coil component 21 and the first external electrode 22b of the varistor component 22, the second external electrode 21c of the coil component 21 and the second external electrode 22c of the varistor component 22, and the main surfaces of the coil component 21 and the varistor component 22. The joint 25 mainly joins the main surfaces of the element body 21a of the coil component 21 and the main surfaces of the element body 22a of the varistor component 22. The joint 25 is, for example, a resin adhesive or the like.

[0068] In the transient voltage protection component 20, the coil component 21 and the varistor component 22 are electrically connected in parallel between the first external electrode 23 and the second external electrode 24.

[0069] When manufacturing the transient voltage protection component 20, the coil component 21 and the varistor component 22 are prepared, and the coil component 21 and the varistor component 22 are joined by a joint 25. Thereafter, a first external electrode 23 (plated) is formed so as to cover the first external electrodes 21b and 22b, and a second external electrode 24 (plated) is formed so as to cover the second external electrodes 21c and 22c. In this way, the transient voltage protection component 20 is manufactured as a single component including the coil component 21 and the varistor component 22.

[0070] 9 is a circuit diagram of the transient voltage protection component 20 shown in FIG. 7. As shown in FIG. 9, the transient voltage protection component 20 is connected between a signal line L1 and a ground line L2. The first external electrode 23 of the transient voltage protection component 20 is connected to the signal line L1, and the second external electrode 24 is connected to the ground line L2. That is, the transient voltage protection component 20 is mounted so that the first external electrode 23 is connected to the signal line L1, and the second external electrode 24 is connected to the ground line L2.

[0071] The coil component 21 and the varistor component 22 of the transient voltage protection component 20 are electrically connected in parallel between the signal line L1 and the ground line L2.

[0072] The coil component 21 is configured to be magnetically saturated when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is a magnetic saturation voltage, which is a voltage higher than the maximum value of the signal voltage flowing through the signal line L1. The signal voltage is the voltage of a control signal or the like flowing through the signal line L1.

[0073] The varistor component 22 is configured to operate when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is the varistor voltage (operating voltage). The varistor voltage can also be said to be the breakdown voltage.

[0074] In the transient voltage protection component 20, the magnetic saturation voltage at which the coil component 21 becomes magnetically saturated is equal to or lower than the varistor voltage at which the varistor component 22 operates (magnetic saturation voltage≦varistor voltage). In this embodiment, the magnetic saturation voltage is lower than the varistor voltage. In this configuration, in the transient voltage protection component 20, magnetic saturation of the coil component 21 occurs before operation of the varistor component 22.

[0075] As described above, the transient voltage protection component 20 according to this embodiment includes the coil component 21. The coil component 21 has high resistance (impedance) to signals with high frequency components, but undergoes magnetic saturation when subjected to a large voltage (load) such as ESD. Thus, when magnetic saturation occurs in the coil component 21, the resistance becomes low, allowing current to flow. Therefore, the transient voltage protection component 20 can release a large voltage, such as ESD, input to the signal line L1 to the ground line L2 (ground G). This reduces the clamp voltage. Furthermore, since the transient voltage protection component 20 includes the coil component 21 and the varistor component 22, the energy of ESD and the like can be distributed between the coil component 21 and the varistor component 22. Therefore, the transient voltage protection component 20 has improved resistance to transient voltages. Therefore, the transient voltage protection component 20 has improved transient voltage protection characteristics.

[0076] In the transient voltage protection component 20 according to this embodiment, the coil component 21 and the varistor component 22 are joined by a joint 25. The joint 25 is made of resin. Therefore, in the transient voltage protection component 20, the linear expansion of the coil component 21 and the varistor component 22 can be absorbed by the joint 25. As a result, the transient voltage protection component 20 can have improved thermal characteristics.

[0077] [Third embodiment] Next, a third embodiment will be described. Fig. 10 is a cross-sectional view of a transient voltage protection component according to the third embodiment. As shown in Fig. 10, a transient voltage protection component 20A includes a coil component (coil portion) 21, a first varistor component (first transient voltage protection portion) 22, a second varistor component (second transient voltage protection portion) 26, a first external electrode 23, and a second external electrode 24. The first varistor component 22 has the same configuration as the varistor component 22 of the second embodiment.

[0078] The second varistor component 26 comprises an element body 26a, a first external electrode 26b, a second external electrode 26c, and an internal electrode 26d.

[0079] The element body 26a has a rectangular parallelepiped shape. The element body 26a is configured by stacking multiple dielectric layers. Each dielectric layer may contain, for example, zinc oxide (ZnO) as a main component, and may also contain, as secondary components, elemental metals such as Co, rare earth metal elements, group IIIb elements (B, Al, Ga, In), Si, Cr, Mo, alkali metal elements (K, Rb, Cs), and alkaline earth metal elements (Mg, Ca, Sr, Ba), as well as oxides of these metals.

[0080] The first external electrode 26b is disposed on one end surface of the element body 26a. The second external electrode 26c is disposed on the other end surface of the element body 26a. The first external electrode 26b and the second external electrode 26c are fired electrodes and made of a conductive material (for example, Ni or Cu).

[0081] The internal electrodes 26d are disposed within the element body 26a. Six internal electrodes 26d are disposed. A plurality (three) of the internal electrodes 26d are connected to the first external electrode 26b. A plurality (three) of the internal electrodes 26d are connected to the second external electrode 26c. The internal electrodes 26d are disposed opposite each other. The internal electrodes 26d are made of a conductive material (for example, Ni or Cu).

[0082] The first external electrode 23 is connected to the second external electrode 22c of the first varistor component 22 and the second external electrode 26c of the second varistor component 26. The second external electrode 22c and the second external electrode 26c are in contact with each other, and the first external electrode 23 is formed so as to cover the second external electrode 22c and the second external electrode 26c.

[0083] The second external electrode 24 is connected to the first external electrode 21b of the coil component 21 and the first external electrode 22b of the first varistor component 22. The first external electrode 21b and the first external electrode 22b are in contact with each other, and the second external electrode 24 is formed so as to cover the first external electrode 22b and the first external electrode 22b. The first external electrode 23 and the second external electrode 24 are platings (plating layers) formed by, for example, electrolytic plating or electroless plating, and made of a conductive material (for example, Ni or Cu).

[0084] In the transient voltage protection component 20A, a connection electrode 22e is arranged on the main surface of the element body 22a of the first varistor component 22. In the transient voltage protection component 20A, the second external electrode 21c of the coil component 21 and the first external electrode 26b of the second varistor component 26 are arranged with their end faces facing each other and are arranged on the connection electrode 22e.

[0085] In the transient voltage protection component 20A, the first varistor component 22, the coil component 21, and the second varistor component 26 are electrically connected in parallel between the first external electrode 23 and the second external electrode 24. The coil component 21 and the second varistor component 26 are electrically connected in series between the first external electrode 23 and the second external electrode 24.

[0086] When manufacturing the transient voltage protection component 20A, the coil component 21, the first varistor component 22, and the second varistor component 26 are prepared, and the coil component 21 and the first varistor component 22 are joined by the joint 25, and the second varistor component 26 and the first varistor component 22 are joined by the joint 25. Thereafter, the first external electrode 23 is formed so as to cover the first external electrode 21b and the first external electrode 22b, and the second external electrode 24 is formed so as to cover the second external electrode 26c and the second external electrode 22c.

[0087] Fig. 11 is a circuit diagram of the transient voltage protection component shown in Fig. 10. As shown in Fig. 11, the transient voltage protection component 20A is connected between the signal line L1 and the ground line L2. The transient voltage protection component 20A has a first external electrode 23 connected to the signal line L1 and a second external electrode 24 connected to the ground line L2. That is, the transient voltage protection component 20A is mounted so that the first external electrode 23 is connected to the signal line L1 and the second external electrode 24 is connected to the ground line L2.

[0088] The coil component 21 is configured to be magnetically saturated when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is lower than the operating voltage (varistor voltage) at which the first varistor component 22 operates and the operating voltage (varistor voltage) at which the second varistor component 26 operates. The predetermined voltage may be lower than the signal voltage.

[0089] The first varistor component 22 is configured to operate when a predetermined voltage or higher is applied. The predetermined voltage is the varistor voltage (operating voltage). The varistor voltage can also be said to be the breakdown voltage.

[0090] The second varistor component 26 is configured to operate when a voltage equal to or greater than a predetermined voltage is applied. The varistor voltage at which the second varistor component 26 operates is higher than the signal voltage of the signal line L1. The sum of the varistor voltage of the second varistor component 26 and the magnetic saturation voltage of the coil component 21 is lower than the varistor voltage of the first varistor component 22.

[0091] In the transient voltage protection component 20A, the first varistor component 22, the second varistor component 26, and the coil component 21 are electrically connected in parallel between the signal line L1 and the ground line L2. The second varistor component 26 and the coil component 21 are electrically connected in series between the signal line L1 and the ground line L2, in this order: the second varistor component 26 and the coil component 21.

[0092] Fig. 12 is a diagram showing the current-voltage characteristics of the transient voltage protection component 20A. In Fig. 12, the horizontal axis represents voltage (V) and the vertical axis represents current (A). Fig. 12 shows the results of TLP (Transmission Line Pulse) measurement. As shown in Fig. 12, in the transient voltage protection component 20A, the current increases nonlinearly with respect to the voltage. In the transient voltage protection component 20A, the coil component 21 and the second varistor component 26 are connected in series, and therefore the characteristics of a varistor are apparent.

[0093] As described above, the transient voltage protection component 20A according to this embodiment includes the coil component 21. The coil component 21 has high resistance (impedance) to signals with high frequency components, but undergoes magnetic saturation when subjected to a large voltage (load) such as ESD. Thus, when magnetic saturation occurs in the coil component 21, the resistance becomes low, allowing current to flow. Therefore, the transient voltage protection component 20A can dissipate a large voltage, such as ESD, input to the signal line L1 to the ground line L2 (ground G). This reduces the clamp voltage. Furthermore, since the transient voltage protection component 20A includes the coil component 21, the first varistor component 22, and the second varistor component 26, energy from ESD and the like can be distributed to the coil component 21, the first varistor component 22, and the second varistor component 26. Therefore, the transient voltage protection component 20A has improved resistance to transient voltages. Therefore, the transient voltage protection component 20A has improved transient voltage protection characteristics.

[0094] In the transient voltage protection component 20A according to this embodiment, the second varistor component 26 and the coil component 21 are connected in series, in this order from the signal line L1 side. With this configuration, when a voltage higher than the sum of the varistor voltage of the second varistor component 26 and the magnetic saturation voltage of the coil component 21 is applied, the resistance is low and current flows. For example, as shown in FIG. 12 , if the transient voltage protection component 20A is operated at a voltage of several tens of volts and only the coil component 21 is used, a coil component 21 capable of handling several tens of volts would be required. In this case, the coil component 21 would be large, making it difficult to miniaturize the transient voltage protection component 20A. In the transient voltage protection component 20A, the second varistor component 26 and the coil component 21 are connected in series, so the magnetic saturation voltage of the coil component 21 may be small. Therefore, a small coil component 21 can be used, thereby miniaturizing the component.

[0095] In the above embodiment, the coil component 21 and the second varistor component 26 are electrically connected in series between the first external electrode 23 and the second external electrode 24, and the second varistor component 26 and the coil component 21 are electrically connected in series between the signal line L1 and the ground line L2 in the order of the second varistor component 26 and the coil component 21. However, the coil component 21 and the second varistor component 26 may also be electrically connected in series in this order between the signal line L1 and the ground line L2.

[0096] [Fourth embodiment] Next, a fourth embodiment will be described. Fig. 13 is a perspective view of a transient voltage protection component according to the fourth embodiment. Fig. 14 is an exploded perspective view of the transient voltage protection component shown in Fig. 13. As shown in Fig. 13 or 14, a transient voltage protection component 30 includes an element body 31, a first external electrode (first electrode) 32, a second external electrode (second electrode) 33, a coil portion 34, and a varistor portion (first transient voltage protection portion) 35.

[0097] The element body 31 is configured by stacking multiple dielectric layers 36. In the element body 31, each dielectric layer 36 configuring the coil portion 34 is configured, for example, from a magnetic material. The magnetic material includes, for example, at least one selected from a Ni-Cu-Zn ferrite material, a Ni-Cu-Zn-Mg ferrite material, and a Ni-Cu ferrite material. The magnetic material of each dielectric layer 36 configuring the coil portion 34 may include an Fe alloy or the like. Each dielectric layer 36 configuring the coil portion 34 may be configured from a non-magnetic material. The non-magnetic material includes, for example, at least one selected from a glass ceramic material and a dielectric material.

[0098] In the element body 31, each dielectric layer 36 constituting the varistor section 35 contains, for example, ZnO (zinc oxide) as a main component, and may contain, as secondary components, elemental metals such as Co, rare earth metal elements, IIIb group elements (B, Al, Ga, In), Si, Cr, Mo, alkali metal elements (K, Rb, Cs) and alkaline earth metal elements (Mg, Ca, Sr, Ba), and oxides of these.

[0099] The first external electrode 32 is disposed on one end surface of the element body 31. The second external electrode 33 is disposed on the other end surface of the element body 31. The first external electrode 32 and the second external electrode 33 are made of a conductive material (for example, Ni or Cu).

[0100] The coil portion 34 is provided on one main surface side of the element body 31. The coil portion 34 is composed of a first coil conductor 37, a second coil conductor 38, and a third coil conductor 39. The first coil conductor 37, the second coil conductor 38, and the third coil conductor 39 are arranged inside the element body 31 and form a coil. The first coil conductor 37, the second coil conductor 38, and the third coil conductor 39 are electrically connected to one another. One end of the first coil conductor 37 is connected to the first external electrode 32. One end of the third coil conductor 39 is connected to the second external electrode 33.

[0101] The varistor section 35 is provided on the other main surface side of the element body 31. The varistor section 35 is composed of a first internal electrode 40 and a second internal electrode 41. The first internal electrode 40 and the second internal electrode 41 are arranged inside the element body 31. The first internal electrode 40 is connected to the first external electrode 32. The second internal electrode 41 is connected to the second external electrode 33.

[0102] In the transient voltage protection component 30 , the coil section 34 and the varistor section 35 are electrically connected in parallel between the first external electrode 32 and the second external electrode 33 .

[0103] Fig. 15 is a circuit diagram of the transient voltage protection component shown in Fig. 13. As shown in Fig. 15, the transient voltage protection component 30 is connected between the signal line L1 and the ground line L2. The first external electrode 32 of the transient voltage protection component 30 is connected to the signal line L1, and the second external electrode 33 is connected to the ground line L2. That is, the transient voltage protection component 30 is mounted so that the first external electrode 32 is connected to the signal line L1, and the second external electrode 33 is connected to the ground line L2.

[0104] The coil section 34 and the varistor section 35 of the transient voltage protection component 30 are electrically connected in parallel between the signal line L1 and the ground line L2.

[0105] The coil portion 34 is configured to be magnetically saturated when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is a magnetic saturation voltage, which is a voltage higher than the maximum value of the signal voltage flowing through the signal line L1. The signal voltage is the voltage of a control signal or the like flowing through the signal line L1.

[0106] The varistor section 35 is configured to operate when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is the varistor voltage (operating voltage). The varistor voltage can also be said to be the breakdown voltage.

[0107] In the transient voltage protection component 30, the magnetic saturation voltage at which the coil section 34 becomes magnetically saturated is equal to or lower than the varistor voltage at which the varistor section 35 operates (magnetic saturation voltage≦varistor voltage). In this embodiment, the magnetic saturation voltage is lower than the varistor voltage. In this configuration, in the transient voltage protection component 30, magnetic saturation of the coil section 34 occurs before the varistor section 35 operates.

[0108] As described above, the transient voltage protection component 30 according to this embodiment includes the coil 34. The coil 34 has high resistance (impedance) to signals with high frequency components, but undergoes magnetic saturation when subjected to a large voltage (load) such as ESD. Thus, when magnetic saturation occurs in the coil 34, the resistance becomes low, allowing current to flow. Therefore, the transient voltage protection component 30 can dissipate a large voltage, such as ESD, input to the signal line L1 to the ground line L2 (ground G). This reduces the clamp voltage. Furthermore, since the transient voltage protection component 30 includes the coil 34 and the varistor 35, the energy of ESD and the like can be distributed between the coil 34 and the varistor 35. Therefore, the transient voltage protection component 30 has improved resistance to transient voltages. Therefore, the transient voltage protection component 30 has improved transient voltage protection characteristics.

[0109] The transient voltage protection component 30 according to this embodiment includes an element body 31 on which a first external electrode 32 and a second external electrode 33 are respectively arranged. The coil portion 34 and the varistor portion 35 are arranged within the element body 31. With this configuration, the transient voltage protection component 30 can be configured as a single component. Therefore, the transient voltage protection component 30 can be made smaller while improving its transient voltage protection characteristics.

[0110] [Fifth embodiment] Next, a fifth embodiment will be described. Fig. 16 is a perspective view of a transient voltage protection component according to the fifth embodiment. Fig. 17 is a side view of the transient voltage protection component shown in Fig. 16. Fig. 18 is a top view of the transient voltage protection component shown in Fig. 16. Fig. 19 is an end view of the transient voltage protection component shown in Fig. 16. As shown in any of Figs. 16 to 19, a transient voltage protection component 50 includes an element body 51, a first external electrode (first electrode) 52, a second external electrode (second electrode) 53, a connection electrode 54, a coil portion 55, a first varistor portion (first transient voltage protection portion) 56, and a second varistor portion (second transient voltage protection portion) 57.

[0111] The element body 51 is configured by laminating multiple dielectric layers. In the element body 51, each dielectric layer configuring the coil portion 55 is configured, for example, from a magnetic material. The magnetic material includes, for example, at least one selected from a Ni-Cu-Zn ferrite material, a Ni-Cu-Zn-Mg ferrite material, and a Ni-Cu ferrite material. The magnetic material of each dielectric layer configuring the coil portion 55 may include an Fe alloy or the like. Each dielectric layer configuring the coil portion 55 may be configured from a non-magnetic material. The non-magnetic material includes, for example, at least one selected from a glass ceramic material and a dielectric material.

[0112] In the element body 51, each of the dielectric layers constituting the first varistor section 56 and the second varistor section 57 may contain, for example, ZnO (zinc oxide) as a main component, and may also contain, as secondary components, elemental metals such as Co, rare earth metal elements, IIIb group elements (B, Al, Ga, In), Si, Cr, Mo, alkali metal elements (K, Rb, Cs), and alkaline earth metal elements (Mg, Ca, Sr, Ba), and oxides of these metals.

[0113] The first external electrode 52 is disposed on one end face of the element body 51. The second external electrode 53 is disposed on the other end face of the element body 51. The connection electrode 54 is disposed on a side face of the element body 51. The first external electrode 52, the second external electrode 53, and the connection electrode 54 are made of a conductive material (for example, Ni or Cu).

[0114] The coil portion 55 is provided in the center of the element body 51. The coil portion 55 is composed of a first coil conductor 55a, a second coil conductor 55b, and a third coil conductor 55c. The first coil conductor 55a, the second coil conductor 55b, and the third coil conductor 55c are arranged inside the element body 51 and form a coil. The first coil conductor 55a, the second coil conductor 55b, and the third coil conductor 55c are electrically connected to one another. One end of the first coil conductor 55a is connected to the connection electrode 54. One end of the third coil conductor 55c is connected to the second external electrode 53.

[0115] The first varistor section 56 is provided on the other main surface side of the element body 51. The first varistor section 56 is composed of a first internal electrode 56a and a second internal electrode 56b. The first internal electrode 56a and the second internal electrode 56b are arranged inside the element body 51. The first internal electrode 56a is connected to the first external electrode 52. The second internal electrode 56b is connected to the second external electrode 53.

[0116] The second varistor portion 57 is provided on one main surface side of the element body 51. The second varistor portion 57 is composed of two first internal electrodes 57a and two second internal electrodes 57b. The first internal electrodes 57a and the second internal electrodes 57b are arranged inside the element body 51. The first internal electrode 57a is connected to the connection electrode 54. The second internal electrode 57b is connected to the first external electrode 52.

[0117] In the transient voltage protection component 50, the first varistor section 56, the coil section 55, and the second varistor section 57 are electrically connected in parallel between the first external electrode 52 and the second external electrode 53. The coil section 55 and the second varistor section 57 are electrically connected in series between the first external electrode 52 and the second external electrode 53.

[0118] Fig. 20 is a circuit diagram of the transient voltage protection component shown in Fig. 16. As shown in Fig. 20, a transient voltage protection component 50 is connected between a signal line L1 and a ground line L2. The transient voltage protection component 50 has a first external electrode 52 connected to the signal line L1 and a second external electrode 53 connected to the ground line L2. That is, the transient voltage protection component 50 is mounted so that the first external electrode 52 is connected to the signal line L1 and the second external electrode 53 is connected to the ground line L2.

[0119] The coil section 55 is configured to be magnetically saturated when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is lower than the operating voltage (varistor voltage) at which the first varistor section 56 operates and the operating voltage (varistor voltage) at which the second varistor section 57 operates. The predetermined voltage may be lower than the signal voltage.

[0120] The first varistor section 56 is configured to operate when a voltage equal to or greater than a predetermined voltage is applied. The predetermined voltage is the varistor voltage (operating voltage). The varistor voltage can also be said to be the breakdown voltage.

[0121] The second varistor section 57 is configured to operate when a voltage equal to or higher than a predetermined voltage is applied. The varistor voltage at which the second varistor section 57 operates is higher than the signal voltage of the signal line L1. The sum of the varistor voltage of the second varistor section 57 and the magnetic saturation voltage of the coil section 55 is lower than the varistor voltage of the first varistor section 56.

[0122] In the transient voltage protection component 50, the first varistor section 56, the second varistor section 57, and the coil section 55 are electrically connected in parallel between the signal line L1 and the ground line L2. The second varistor section 57 and the coil section 55 are electrically connected in series between the signal line L1 and the ground line L2, in this order: second varistor section 57, coil section 55.

[0123] As described above, the transient voltage protection component 50 according to this embodiment includes the coil 55. The coil 55 has high resistance (impedance) to signals with high frequency components, but undergoes magnetic saturation when subjected to a large voltage (load) such as ESD. Thus, when magnetic saturation occurs in the coil 55, the resistance becomes low, allowing current to flow. Therefore, the transient voltage protection component 50 can dissipate a large voltage, such as ESD, input to the signal line L1 to the ground line L2 (ground G). This reduces the clamp voltage. Furthermore, since the transient voltage protection component 50 includes the coil 55, the first varistor 56, and the second varistor 57, energy from ESD and the like can be distributed to the coil 55, the first varistor 56, and the second varistor 57. Therefore, the transient voltage protection component 50 has improved resistance to transient voltages. Therefore, the transient voltage protection component 50 has improved transient voltage protection characteristics.

[0124] In the transient voltage protection component 50 according to this embodiment, the second varistor section 57 and the coil section 55 are connected in series in this order from the signal line L1 side. With this configuration, when a voltage higher than the sum of the varistor voltage of the second varistor section 57 and the magnetic saturation voltage of the coil section 55 is applied, the resistance becomes low and current flows. For example, if the transient voltage protection component 50 is operated at a voltage of several tens of volts and only the coil section 55 is used, a coil section 55 capable of handling several tens of volts must be provided. In this case, the coil section 55 may become large, making it difficult to miniaturize the transient voltage protection component 50. In the transient voltage protection component 50, the second varistor section 57 and the coil section 55 are connected in series, so the magnetic saturation voltage of the coil section 55 may be small. Therefore, a small coil section 55 can be used, thereby miniaturizing the component.

[0125] Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0126] In the above embodiment, the varistor component 10 is used as the transient voltage protection unit. However, the transient voltage protection unit may be, for example, a diode.

[0127] In the above embodiment, as shown in FIG. 3, a configuration in which current flows continuously between the first switching point (first threshold voltage V1) and the second switching point (second threshold voltage V2) has been described as an example. However, as shown in FIG. 21, in the transient voltage protection circuit, the waveform may be discontinuous between the first switching point (first threshold voltage V1) and the second switching point (second threshold voltage V2). In this configuration, the resistance becomes low immediately after the first switching point, allowing current to flow. This improves the clamping characteristics. [Explanation of symbols]

[0128] 1, 20, 20A, 30, 50... transient voltage protection component, 2... base, 3... first terminal electrode (first electrode), 4... second terminal electrode (second electrode), 5... first land electrode, 6... second land electrode, 7... third land electrode (first land electrode), 8... fourth land electrode (second land electrode), 9, 21... coil component (coil portion), 10, 22... varistor component (first transient voltage protection portion), 11... sealing portion, 23, 32 ,52...first external electrode (first electrode), 24,33,53...second external electrode (second electrode), 25...junction, 26...second varistor component (second transient voltage protection section), 34,55...coil section, 35...varistor section (first transient voltage protection section), 56...first varistor section (first transient voltage protection section), 57...second varistor section (second transient voltage protection section), G...ground, V1...first threshold voltage, V2...second threshold voltage.

Claims

1. A coil portion; a first transient voltage protector; a second transient voltage protection unit; a first electrode and a second electrode, the coil unit and the first transient voltage protection unit are connected in parallel between the first electrode and the second electrode; the first transient voltage protection unit, the coil unit, and the second transient voltage protection unit are connected in parallel between the first electrode and the second electrode; the coil unit and the second transient voltage protection unit are connected in series in this order from the first electrode side, the coil portion is configured to be magnetically saturated when a voltage higher than a predetermined voltage is applied thereto; A transient voltage protection component, wherein a magnetic saturation voltage at which the coil portion is magnetically saturated is lower than an operating voltage at which the first transient voltage protection portion operates.

2. The transient voltage protection component according to claim 1 , wherein the predetermined voltage is equal to or lower than an operating voltage at which the first transient voltage protection unit operates.

3. each of the coil unit and the first transient voltage protection unit is a chip component; a base on which the first electrode and the second electrode are disposed; a first land electrode disposed on the base and connected to the first electrode; a second land electrode disposed on the base and connected to the second electrode; a sealing portion that seals the coil portion and the first transient voltage protection portion, The transient voltage protection component according to claim 1 or 2, wherein the coil portion and the first transient voltage protection portion are connected to the first land electrode and the second land electrode, respectively.

4. The transient voltage protection component according to claim 3 , wherein a distance between the coil portion and the transient voltage protection portion is smaller than a distance between the first land electrode and the second land electrode.

5. each of the coil unit and the first transient voltage protection unit is a chip component; The transient voltage protection component according to claim 1 or 2, wherein the coil portion and the first transient voltage protection portion are joined by a joining portion made of resin.

6. an element body on which the first electrode and the second electrode are respectively disposed, The transient voltage protection component according to claim 1 or 2, wherein the coil portion and the first transient voltage protection portion are disposed within the element body.

7. 7. The transient voltage protection component according to claim 1, wherein the current-voltage characteristic switches at a first threshold voltage and also switches at a second threshold voltage that is lower than the first threshold voltage.

8. The mounting structure of the transient voltage protection component according to any one of claims 1 to 7, The first electrode is connected to a signal line, and the second electrode is connected to ground.

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