WO2011045279A1

WO2011045279A1 - Electrical component

Info

Publication number: WO2011045279A1
Application number: PCT/EP2010/065213
Authority: WO
Inventors: Thomas Feichtinger; Klaus Reichmann
Original assignee: Epcos Ag
Priority date: 2009-10-12
Filing date: 2010-10-11
Publication date: 2011-04-21
Also published as: DE102009049076A1

Abstract

The invention relates to an electrical component comprising at least two varistor ranges (2a, 2b). Each of the varistor ranges (2a, 2b) comprises at least one first electrode (4a, 4b), wherein at least two varistor ranges (2a, 2b) comprise at least one common second electrode (5). The electrical component comprises at least one conductive segment (3) integrated in the electrical component (1) and disposed between the at least two varistor ranges (2a, 2b). The conductive segment (3) protects the electrical component (1) from damage.

Description

Description Electrical component From the document US 5,982,597 is an electrical

Component is known in which a fuse is integrated to protect the device.

An object to be solved is to provide an electric component which can be produced in a simple manner, in which a protection against damage by electrical load is provided.

The task is followed by an electrical component

Claim 1 solved. Advantageous embodiments of the electrical component are the subject of dependent claims.

An electrical component is specified which has at least two varistor regions. Each of the varistor regions has in each case at least one first electrode. The at least two varistor regions have at least one common second electrode. The electrical component has at least one electrically conductive portion which is arranged between the at least two varistor regions. The electrically conductive portion is disposed in the electrical component ^¬ rule. The conductive portion is formed so that the electrical component is protected from Beschädigun ^¬ gene, which may occur at a longer lasting load of the electrical component.

In one embodiment, the conductive portion has the function of a fuse for the electrical

Component on. The fuse is preferably integrated in the electrical component and is arranged between the at least two varistor regions. In one embodiment, the conductive portion is designed as a conductive web.

In one embodiment, the conductive portion comprises a material that melts at high temperatures. Preferably, the melting range of the conductive portion is below the temperature range at which the electrical component is located

permanent damage. In a further embodiment, the electrically conductive portion is designed as a resistor between the first electrodes of the varistor regions. The resistor have preferably ^¬ as a temperature-dependent resistance. This is preferably a resistor with a positive temperature coefficient. The resistance is thus increasingly high impedance with increasing temperature and reduces the current flow accordingly, which avoids further increase in temperature. From a certain temperature, the electrical component is protected by the resistor from destruction by a too high temperature.

As a conductive bridge is an area between the first

To understand electrodes, which preferably has a reduced cross-section with respect to the first electrodes. The conductive web can be understood, for example, as an incision in the electrode layer.

Preferably, a varistor ceramic is arranged between at least two first electrodes and at least one second electrode. The varistor ceramic has a variable resistance.

When a permissible maximum current intensity is exceeded, a varistor changes from the low-impedance state to the high-impedance state. The conductive web of fusible material connects the two varistor areas and has one Function similar to a fuse, which is destroyed at a correspondingly high temperature.

In one embodiment, at least two of the first electrodes each have an external contact via which the first electrodes can be electrically contacted from the outside.

At least one second electrode of the electrical component has an external contact via which the second

Electrode can be contacted electrically from the outside.

In one embodiment, the varistor ceramic of the electrical component comprises, for example, zinc oxide bismuth (ZnO-Bi), zinc oxide praseodymium (ZnO-Pr), strontium titanate (SrTiO 3) or silicon carbonate (SiC).

In one embodiment, the varistor ceramic of the electrical component has a disk-like contour. In this embodiment, the electrical component thus has a disc-shaped body.

In a further embodiment, the body of the

electrical component, for example, a round, oval or another shape.

In one embodiment, the first and second

Electrodes as well as the electrical contact surfaces as well

Through-holes silver (Ag), silver palladium (AgPd), palladium (Pd), silver platinum (AgPt), platinum (Pt) or copper (Cu) on.

In a further embodiment, for example, a plurality of electrical components as described above may be arranged in a multilayer component. In one embodiment, the multilayer component has a plurality of electrode stacks with internal electrodes. The

Electrode stacks each form at least one

Varistor area.

In one embodiment, groups of internal electrodes are electrically conductively connected to associated external contact surfaces. In one embodiment, at least two outer contact surfaces ^{¬ are} connected by means of an electrically conductive web. The conductive land is used in this embodiment as

Fuse. At least one third external contact surface is electrically connected to ground.

In one embodiment, the multilayer component has at least two varistor regions, each through

Stack of first internal electrodes are formed. Between the first internal electrodes are each second more

Internal electrodes arranged, which are preferably connected to ground. Layers of varistor ceramic are arranged between the electrode layers.

In a further embodiment, a plurality of these multilayer arrangements are arranged in a single component. The individual electrical components of the multilayer component are preferably arranged next to one another.

In one embodiment, the individual electrical components are arranged such that they are independent

can be connected from each other. The single ones

electrical components of the multilayer component are in this embodiment with each other by insulating

Separated areas.

In a further embodiment, the individual electrical components can also be electrically interconnected within the multilayer component.

By integrating a fuse in an electrical component, the electrical component is protected against thermal overload. Due to the properties of the varistor, the metallic structure of the fuse is protected against pulse degradation. At the same time, the fuse prevents a short circuit across the varistor areas in the event of overloading.

The electrical component described above, is used

Preferably, to protect an electrical circuit from short circuits due to overload, wherein in the electrical component, the two varistor regions are connected in parallel to each other and between the varistor regions a

Fuse are arranged. The varistor regions are connected to a first contact of a signal line

contacted protective circuit. About a second

electrical contact are the varistor regions against a reference line, e.g. Ground switched.

Thus, it is possible, for example, to arrange a plurality of electrical components with at least two varistor regions in a common component, wherein the individual electrical components of the arrangement can be connected separately from one another.

The above-described objects are described with reference to FIG

The following figures and embodiments explained in more detail.

The drawings described below are not to be considered as true to scale, but the representations enlarged, reduced or distorted in individual dimensions. Elements that are equal to each other or that perform the same function are denoted by the same reference numerals.

Figure 1 shows a schematic structure of a first

Embodiment in which two

Varistor areas of an electrical component by means of an electrically conductive web

connected to each other,

FIG. 2 shows the rear side of the component of FIG. 1,

Figure 3 shows schematically another

Embodiment of an electrical component in multilayer construction,

FIG. 4 shows a cross section

Embodiment,

Figure 5 shows schematically another

Embodiment in which a plurality of electrical components are arranged in a multilayer component,

FIG. 6 shows a cross section of a

Embodiment,

7a-c show a plan view and side views of a multilayer component in which a plurality of electrical components are arranged in a common multilayer component,

Figure 8 shows schematically a replacement circuit arrangement in which a

Embodiment of the electrical component and a circuit to be protected are shown.

1 shows a schematic structure of a first embodiment in which two first electrodes 4a, 4b of the varistor regions 2a, 2b of an electrical component 1 are connected to one another by means of an electrically conductive web 6. The conductive web 6 comprises an electrically conductive material which begins to melt at a certain temperature before the varistor regions 2a, 2b are damaged. The conductive web 6 has, for example, the function of an electrical fuse 3.

The first electrodes 4a, 4b of the two varistor regions 2a, 2b are applied to a varistor ceramic 7 through metallized regions. The metallized regions each form a first electrode 4a, 4b of a varistor region 2a, 2b. The second electrode of the varistor regions 2a, 2b is applied to the back of the varistor ceramic 7 and serves for the two varistor regions 2a, 2b together.

The varistor regions 2 a, 2 b each have an external electrical contact 8 a, 8 b, via which the varistor regions 2 a, 2 b can be electrically contacted from the outside. An electrical equivalent circuit diagram of an electrical component 1 is shown in FIG.

FIG. 2 shows the rear side of the exemplary embodiment according to FIG. 1, which shows a varistor ceramic 7 with an applied second electrode 5. The second

Electrode 5, together with the first electrodes on the front side of the varistor ceramic 7 and the varistor ceramic 7 arranged therebetween, forms the varistor regions 2a, 2b. The second electrode 5 covered in the illustrated embodiment ^¬ form the varistor ceramic 7 over its entire surface. However, it is also possible for the second electrode 5 to comprise only partial areas of the area as long as two varistor areas are formed.

The first electrodes 4a, 4b, which are shown in FIG. 1, together with the varistor ceramic 7 and the common second electrode 5, which is shown in FIG. 2, form two varistor regions 2a, 2b between which a fuse 3 is connected , The fuse is formed in the illustrated embodiment by a conductive metallic web. FIG. 3 shows schematically another ^exemplary embodiment of the electrical component, which shows a multilayer component in plan view. In the illustrated view of the multilayer component, the internal electrodes of the multilayer component are more than one overlapping one another

Layers shown.

The multilayer component has two varistor regions 20a, 20b, which are formed by first electrodes 21a, 21b and second electrodes 22. At least one electrically conductive web 23 is arranged between the varistor regions 20a, 20b and begins to melt at a specific temperature and is connected between the varistor regions 20a, 20b in accordance with the function of a fuse. The fuse protects the varistor regions 20a, 20b of the multilayer component against overloading.

The first electrodes 21a, 21b are metallized over

Contact surfaces 24a, 24b on the outside of the Multilayer component electrically contacted. The second electrodes 22 can likewise be electrically contacted from outside via metallized contact surfaces 24c. FIG. 4 shows a cross-section of a further exemplary embodiment of the multilayer component, the section corresponding to the section axis A - A 'in FIG. The electrical component is constructed in multilayer construction of several layers of a varistor 7 ceramic. The layers of the varistor ceramic comprise several metallized areas. The metallized regions form first and second internal electrodes 21a, 21b and 22, respectively, which can be contacted from outside via metallized contact surfaces 24a, 24b, 24c. The first electrodes 21a, 21b are stack-shaped arranged one above the other and together with common second electrodes 22 each form a first and a second varistor region 20a and 20b. Between the varistor regions 20a, 20b, an electrically conductive web 23 is arranged in the function of a fuse. In the illustrated

Embodiment, the conductive ridge 23 on the outside of the multilayer component between the outer contact ^¬ surfaces 24 a, 24 b of the two varistor regions 20 a, 20 b

arranged. As an alternative to the exemplary embodiment according to FIG. 4, the conductive web 23 may, for example, comprise a temperature-dependent resistor which is arranged between the outer contact surfaces 24a, 24b of the two varistor regions 20a, 20b. In a further possible embodiment, the conductive web 23 can be arranged within the multilayer component in the region of the first 21a, 21b and second 22 electrodes. FIG. 5 shows a further exemplary embodiment, in which a plurality of electrical components are arranged together in a multilayer component. In the illustrated embodiment, the multilayer component has four first electrodes 21a, 21b per layer, of which two first electrodes 21a, 21b are respectively arranged on opposite sides of the component. The first electrodes 21a, 21b are electrically insulated from each other and are external contact ^¬ surfaces 24a, 24b can be electrically contacted from the outside. The multilayer component has layers with second electrodes 22 between the first electrodes 21a, 21b. At least one layer of a varistor ceramic is arranged between the layers with the first and second electrodes 21a, 21b and 22, respectively. The second electrodes 22 are over outer

Contact surfaces 24c contacted from the outside. The second

Electrodes 22 overlap with the first electrodes 21a, 21b and form in each case a varistor region 20a, 20b in the overlap regions together with the varistor ceramic. The multilayer component has in the illustrated

Embodiment for protecting the varistor regions 20a, 20b on conductive webs 23, which begin to melt from a certain temperature and thereby protect a downstream not shown electrical circuit. The conductive webs 23 have the function of a fuse in the illustrated embodiment.

The conductive webs 23 are arranged in the figure 5 between the first electrodes 21a, 21b. The conductive webs 23 can be arranged both in the plane of the first electrodes 21a, 21b, as well as otherwise, for example on the top and / or bottom of the multilayer component. In the embodiment in which the conductive webs 23 are arranged on the top and / or bottom, the conductive webs 23 preferably have a direct electrical contact to the outer contact surfaces 24a, 24b of the first electrodes 21a, 21b. The conductive webs 23 are

preferably isolated from the second electrodes 22 and the outer contact surfaces 24c of the second electrodes 22.

FIG. 4 shows a cross-section of a further exemplary embodiment of the multilayer component, the section corresponding to the section axis B - B 'in FIG. 5. In the cross section, an embodiment of the multilayer component is shown, in which the conductive web 23, contrary to the embodiment in Figure 5, is arranged on the upper side of the multilayer component. The conductive land is disposed between the outer contact surfaces 24a, 24b of the first electrodes 21a, 21b.

The multilayer component has a plurality of internal electrodes, wherein first electrodes 21a, 21b are spaced apart from one another. The multilayer component has second electrodes 22, which form overlapping regions with the first electrodes 21a, 21b. The overlapping regions in combination with a varistor ceramic 7 between the first 21a, 21b, and second 22 electrodes form two varistor regions 20a, 20b, which are illustrated by a dashed line.

FIG. 7a shows a top view of a multilayer component, wherein a plurality of electrical components are arranged in a common multilayer component. The

Multi-layer component has a plurality of outer contact surfaces 24a, 24b, 24c. In each case two outer contact surfaces 24a, 24b are connected to a conductive web 23. The outer contact regions 24a, 24b are connected to first electrodes 21a, as shown in FIGS. 7b and 7c. The Further outer contact regions 24c are connected via through-connections 25 to second electrodes 22. Of the

conductive ridge 23 between the outer contact surfaces 24a, 24b serves as a fuse between two Varistorbereichen. The varistor regions are formed by the first and the second electrodes and varistor ceramic. A detailed view of the varistor regions is shown in dashed lines in FIG. 7b. The outer contact areas 24a, 24b, 4c are formed in the Darge ^¬ presented embodiment as so-called bumps. As a result, for example, a flip-chip mounting of

Multilayer component on a support with interconnects possible, which is not shown in this figure.

FIG. 7b shows a cross section of the exemplary embodiment according to FIG. 7a along the section axis A-A '. The multilayer component comprises a plurality of stacks of Innenelek ^¬ trodes, wherein the inner electrodes in the first 21a, 21b and second electrodes 22 are distinguished. The first electrodes 21a, 21b are spaced apart from each other. The second electrode 22 overlap with the first electrodes 21a, 21b so forming the overlapping areas together with a varistor ceramic ^¬ 7 Varistorbereiche 20a, 20b. In FIG. 7b, only the first varistor regions 20a are shown. The further varistor regions 20b are behind the cutting plane.

FIG. 7c shows a cross section of the embodiment according to FIG. 7a along the section axis B - B '. The view of Figure 7c shows the first electrodes 21a, 21b, which are spaced apart in the horizontal direction and in the vertical direction with the same kind of first electrodes 21a, 21b each form a stack of internal electrodes. The The first electrodes 21a, 21b are electrically conductively connected via plated-through holes 25 to the outer contact surfaces 24a, 24b on the upper side of the multilayer component. By means of the plated-through holes 25, it is possible to electrically connect internal electrodes of different layers of a multilayer component with one another. In the illustrated embodiment, is on top of the Vielschichtbauele ^¬ ment between the outer contact surfaces 24a, 24b of the first electrodes 21a, 21b of the electrically conductive web 23

arranged.

In a further embodiment, it is also possible that, be arranged in place of a fusible conductive fin temperaturab a ^¬-dependent resistor, such as a PTC.

FIG. 8 schematically shows a replacement circuit ^arrangement with an electrical component 1 as described above and an electrical circuit 30 to be protected. The electrical component 1 has two

Varistor regions 2a, 2b, which are connected in parallel between the supply line to be protected electrical circuit 30 and ground. Between the varistor regions 2a, 2b a fuse 3 is arranged. By an integration of a fuse 3 in an electrical

Component is protected against thermal overload. Due to the properties of a varistor, the metallic structure of the fuse 3 is subject to pulse degradation

protected. At the same time, it is prevented by the fuse 3 that, in the event of a thermal overload, a short circuit occurs across the varistor regions 2 a, 2 b. Although only a limited number of possible developments of the invention could be described in the embodiments, the invention is not limited to these. It is in principle possible for the electrical component to have a plurality of varistor regions connected in series, between which one or more fuses are respectively arranged.

The description of the subject matters herein is not limited to the particular specific embodiments; Rather, the features of the individual embodiments, as far as technically feasible, can be combined with each other.

Reference sign list

1 electrical component

2a, 2b varistor region

3 fuse

4a, 4b first electrode

5 second electrode

6 conductive footbridge

7 varistor ceramics

8a, 8b, 8c external contact

9 internal electrodes

20a, 20b varistor area

21a, 21b first electrode

22 second electrode

23 conductive footbridge

24a, 24b, outer contact surface

25 via 30 electrical circuit

Claims

claims

1. having electrical component,

at least two varistor regions (2a, 2b),

wherein each of the varistor regions (2a, 2b) has at least one first electrode (4a, 4b), wherein the at least two varistor regions (2a, 2b) have at least one common second electrode (5),

at least one conductive section (3) integrated in the electrical component (1) and between the at least two varistor sections (2a, 2b)

is arranged, and the

is formed to protect the electrical component (1) from damage.

2. Electrical component according to claim 1, wherein the

conductive portion (3) in the form of a conductive web (6).

3. Electrical component according to one of the preceding claims, wherein between the at least two first electrodes (4a, 4b) and the at least one second electrode (5) a varistor ceramic (7) is arranged.

4. Electrical component according to one of the preceding claims, wherein the at least two first electrodes (4a, 4b) and the second electrodes (5) each have an external contact (8a, 8b).

5. Electrical component according to one of the preceding claims, wherein the varistor ceramic (7) ZnO-Bi, ZnO-Pr, SrTi03 or SiC comprises.

6. The electrical component according to one of the preceding claims, wherein the first (4a, 4b) and the second (5) electrodes Ag, AgPd, Pd, AgPt, Pt or Cu have.

7. multilayer component, comprising at least two

Electric components (1) according to one of claims 1 to 6.

8. multilayer component according to claim 7, the plurality

Electrode stack of first (21 a, 21 b) and second (22) electrodes, which together with a

Varistor ceramic (7) each at least one

Varistor region (20a, 20b) form.

9. multilayer component according to claim 8, wherein the

Internal electrodes (21a, 21b, 22) via vias (25) are electrically connected to outer contact surfaces (24a, 24b, 24c).

10. A multilayer component according to claim 9, wherein at least two outer contact surfaces (24a, 24b) by means of a conductive web (25) are connected.

11. A multilayer component according to claim 10, wherein at least a third outer contact surface (24c) is electrically connected to a reference potential.