EP3769323A1

EP3769323A1 - Inductive component and high-frequency filter device

Info

Publication number: EP3769323A1
Application number: EP19708835.4A
Authority: EP
Inventors: Johann W. Kolar; Dominik Bortis; Jannik Robin SCHAEFER
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-03-22
Filing date: 2019-03-01
Publication date: 2021-01-27
Anticipated expiration: 2039-03-01
Also published as: DE102018204366A1; CN111886661B; US20200411222A1; EP3769323B1; US11817243B2; CN111886661A; WO2019179749A1

Abstract

The invention relates to an inductive component having a planar conductive track structure. The planar conductive track structure is surrounded along a predetermined section by a ferromagnetic core. For targeted control of the current flow inside the planar conductive track structure and, in particular, of the current density in the cross-section of the planar conductive track structure, gaps are provided in a targeted manner in the ferromagnetic core. The gaps in the ferromagnetic core are arranged in regions above and/or below the planar conductive track structure.

Description

description

title

Inductive component and high-frequency filter device

The present invention relates to an inductive component. Furthermore, the present invention relates to a high-frequency filter device with such an inductive component.

State of the art

In electronic circuits inductors, which are designed for high currents and high frequencies, often realized as discrete components and then soldered to a circuit board. As part of an optimization, it is desirable to integrate the windings in the form of copper tracks directly on a printed circuit board for inductive components.

WO 2004/030001 A1 discloses a high-frequency choke for printed circuit boards with an inductance and a parallel-connected ohmic resistance. In this case, the inductance can be realized from a meander-like conductor track.

In applications with high frequencies, due to the so-called skin effect, the electric current flows with increasing frequency only in an edge region of the electrical conductor. Therefore, especially in printed electrical circuits for higher-frequency applications, only the edge region of the conductor tracks is available for an electric current flow.

Disclosure of the invention The present invention discloses an inductive component with the

Features of claim 1, and a high-frequency filter device with the features of claim 10.

Accordingly, it is provided:

An inductive component with a planar track structure and a ferromagnetic core. The planar conductor track structure has an upper side and a lower side opposite the upper side. Of the

Ferromagnetic core is around the planar interconnect structure around

arranged. In particular, the ferromagnetic core comprises at least one gap in the region of the top side and / or the underside of the planar conductor track structure.

Preferably, the planar conductor track structure has a longitudinal extent, which in the direction of a desired current flow through the planar

Track structure is aligned. Preferably, the planar

Conductor structure has a transverse extent, which is aligned perpendicular to the direction of the desired current flow through the planar conductor track structure. A diagonal of the cross section of the ferromagnetic core is oriented perpendicular to the direction of the desired current flow. Thus, the ferromagnetic core, which is preferably configured tubular or annular, at least partially disposed along the longitudinal extent of the planar conductor track structure around the planar conductor track structure around. The term tubular or annular includes in this description preferably in addition to rectangular or polygonal cross-sections also round or oval cross-sections with a.

Furthermore, it is provided:

A high-frequency filter device with an inductive component according to the invention.

Advantages of the invention The present invention is based on the finding that at

High-frequency electrical currents through an electrical conductor due to the skin effect of the current flow increasingly takes place only in the outer region of the electrical conductor. In addition, the present invention is based on the finding that by magnetic cores with an air gap, due to the inhomogeneous distribution of a magnetic field due to the air gap, also a partial current displacement within an electrical conductor can be caused.

The present invention is therefore based on the idea to take this finding into account and to provide an arrangement for an inductive component, which also for high-frequency electrical currents a high

Current carrying capacity. For this purpose, an arrangement of a planar electrical conductor and a surrounding the electrical conductor

ferromagnetic core, wherein the Stromverdrängängungseffekte due to a gap in the ferromagnetic core the

Counteract current displacement effects due to the skin effect.

This makes it possible to distribute the electrical current flow over a large area of the cross section of the electrical conductor, especially in the case of planar printed conductor structures. In this way, the current carrying capacity of the planar electrical conductor can be increased.

As a planar conductor track structure can initially be any kind of

Track structure to be understood, which has a cross-sectional area perpendicular to the intended current flow direction in which the expansion in one direction is significantly greater than the extension in a direction perpendicular thereto extending further direction. In particular, the difference between the two dimensions may be at least one order of magnitude or more. As a planar conductor structures, for example, printed

Track structures are understood on a printed circuit substrate.

For example, an electrically conductive material, such as copper or the like, can be applied to the printed circuit board substrate, which runs according to a desired printed conductor structure. In addition, however, planar planar structures are also any other planar ones

Track structures to understand. In particular, the planar must Conductor structures are not applied to a full-surface carrier substrate. In principle, it is also possible for the planar conductor track structures to be supported only partially, for example at support points.

In a simple case, the planar printed conductor structure can consist, for example, of a linearly extending planar electrically conductive element. In addition, however, the planar wiring pattern may also be formed by a coil-like wiring pattern having any number of two or more turns. The individual turns can in this case, as will be described in more detail below, for example, side by side or one above the other. A combination of these is possible.

In this case, in particular those sides of the printed conductor structure are to be understood as the top side and underside of the planar printed conductor structure, which are perpendicular to the desired electric current flow, the larger

in particular have the largest extent. The top of the

Conductor structure is arranged opposite the underside of the conductor track structure. The upper side and the lower side of the conductor track structure can be connected to one another in each case by means of two side surfaces in the case of a, for example, rectangular cross-section of the conductor track structure.

The planar printed conductor structure is surrounded along a predetermined section with the ferromagnetic core. The ferromagnetic core can at least approximately completely enclose the planar conductor track structure. However, the ferromagnetic core has one or more gaps in its circulation. This gap or these gaps are arranged in particular in the region of the upper side and / or the lower side of the planar conductor track structure. The term "in the region" of the upper side or the lower side is to be understood as meaning that a virtual line, which can run perpendicular to the upper side or the lower side, also runs through such a gap. Thus, such a gap in the region of the upper side or the lower side of the planar printed conductor structure clearly differs from columns which are arranged laterally on a planar printed conductor structure. A ferromagnetic core of an inductive component according to the present invention comprises preferably no such lateral column in the region of the side surfaces of the planar conductor track structure.

The ferromagnetic core may be formed of any ferromagnetic material. Such ferromagnetic materials are known and are therefore not explained here.

As will be explained in more detail below, the gap in the ferromagnetic core may be an air gap or a gap at least partially filled with a dielectric material.

The ferromagnetic core may in this case have gaps both in the region of the upper side and in the region of the lower side of the planar printed conductor structure. In particular, the arrangement of one or more gaps in the region of the upper side of the planar printed conductor structure and in the region of the underside of the printed conductor structure can be identical or at least approximately equal. In addition, however, fundamentally different designs with one or more gaps in the region of the upper side or the lower side of the planar printed conductor structure are also possible.

According to one embodiment, the ferromagnetic core comprises a plurality of gaps. In particular, a plurality of gaps can be provided both in the region of the upper side and in the region of the lower side. For example, the individual gaps can each have an identical gap width. In addition, the gap width of individual column can also be varied depending on further requirements. By arranging a plurality of gaps, in particular a magnetic flux can be set which further improves the homogeneous distribution of the current flow within the planar printed conductor structure.

According to one embodiment, the planar conductor track structure may comprise a plurality of parallel conductor tracks. Each of these individual parallel conductor tracks can also have a planar structure, wherein the cross section of such a track structure in a spatial direction is significantly greater than the cross section in a perpendicular thereto Spatial direction. In particular, an increased inductance of the inductive component can be achieved by using a plurality of strip conductors.

According to one embodiment, the planar conductor track structure comprises a plurality of conductor tracks arranged one above the other. In this case, the term "one above the other" is to be understood as meaning that in each case the underside of a conductor track and the upper side of an adjacent conductor track are located opposite one another. The individual conductor tracks can be spaced apart, for example, by means of an electrically insulating substrate. In this way, a multi-turn coil arrangement can be realized. According to one embodiment, the planar conductor track structure may comprise a plurality of coplanar conductor tracks. In such a coplanar arrangement several, in particular a plurality of parallel conductor tracks are arranged in a common plane. For example, the individual

Conductor tracks may be arranged on a common carrier substrate. It is understood that the arrangement of several komplanar arranged

Tracks and the arrangement of several stacked

Tracks as previously described, can also be combined with each other.

According to one embodiment, in particular in a coplanar

Arrangement of a plurality of conductor tracks in the region of the top and / or the bottom of each conductor track arranged at least one gap. In this way, the most homogeneous possible current distribution within the respective conductor track can be achieved for each conductor track of the conductor track structure.

According to one embodiment, at least one gap of the

ferromagnetic core at least partially with a dielectric

Fill filled. In particular, all the gaps of the ferromagnetic core may be filled with the same filler material. But also different filling materials for each column are possible.

By using a suitable filling material, the magnetic flux can be influenced and thereby the current distribution within the planar conductor track structure can be controlled. In addition, through the Use of a filling material and the arrangement, in particular the magnetic core are mechanically stabilized.

According to one embodiment, the ferromagnetic core comprises rounded edges in the transition to the gap. By rounding the edges in the ferromagnetic core, in particular by the use of rounded edges in the region of the column can also influence the

magnetic field and thus influencing the power distribution can be achieved within the planar interconnect structure.

According to one embodiment, the magnetic core in the region of the top side and / or the underside of the planar printed conductor structure comprises a material with ferromagnetic powder particles. The partial use of such ferromagnetic powder particles can also influence the magnetic flux. In particular, magnetic cores having such ferromagnetic particles are also known as powder cores or cores having a so-called distributed air gap.

According to one embodiment, the inductive component comprises a

Carrier substrate. In particular, the planar printed conductor structure can be connected to the underside and / or the upper side with a dielectric carrier substrate. For example, it may be in the dielectric

Carrier substrate to act around a printed circuit board substrate. As a result, for example, a planar can be particularly simple

Track structure can be realized. In particular, multi-layered structures with a plurality of carrier substrates and / or a plurality of planar

Track structures possible.

The above embodiments and developments can, as far as appropriate, combine arbitrarily. Further refinements, further developments and implementations of the invention also include combinations of previously or below that are not explicitly mentioned with respect to FIG

Embodiments described features of the invention. In particular, the person skilled in the art will also consider individual aspects as improvements or

Add supplements to the respective basic forms of the invention. Brief description of the drawings

The present invention will be explained in more detail with reference to the embodiments given in the schematic figures of the drawings. Showing:

Figure 1: a schematic representation of a cross section through a

inductive component according to an embodiment;

Figure 2 is a schematic representation of a cross section through a

inductive component according to another embodiment;

Figure 3: a schematic representation of a cross section through a

inductive component according to yet another embodiment;

Figure 4: a schematic representation of a cross section through a

Part of an inductive component according to a

embodiment;

5a, 5b: a perspective view of an inductive component according to another embodiment; and

Figure 6: a schematic representation of a cross section through a

conventional component.

Description of the embodiments

In the following description, the same or similar elements will be denoted by like reference numerals. In addition, the

Embodiments described below, as far as appropriate, are arbitrarily combined.

Figure 6 shows a cross section through an arrangement for an inductive

Component. On a carrier substrate 130 is an electrically conductive Printed wiring pattern 110 applied. For example, it may be a printed conductor on a printed circuit board substrate. The height h of the conductor track structure 110 is significantly less than the width b of the

Printed Circuit Structure 110. The conductive pattern 110 is surrounded by two half-shells 120 which are to form a magnetic core. Due to the continuous carrier substrate 130, the core formed by the two half shells 120 is interrupted at the positions 121. Therefore, the

magnetic core at the positions 121 each have a gap, which increases the magnetic field strength in this area.

In an arrangement shown in FIG. 6, the course of the magnetic field lines due to the position of the gaps 121 in the magnetic core leads to a current displacement in the conductor track 110 towards the edges of the conductor track structure 110.

If, in addition, the electrical conductor 110 is traversed by a high-frequency electrical current, the current flow also shifts into the edge regions of the electrical conductor 110. In this way, the maximum current carrying capacity is significantly reduced.

FIG. 1 shows a schematic illustration of a cross section through an inductive component 1 according to an embodiment. The inductive

Component 1 comprises a planar conductor track structure 10 and a

ferromagnetic core 20. The cross section of the planar conductor track structure 10 has a height h which is significantly smaller than the width b of the planar conductor track structure. The width b points in the direction of

Transverse extension of the planar conductor track structure 10. In particular, the width b may be greater than the height h by more than an order of magnitude, that is to say the factor 10. Along a predetermined section in the direction of the longitudinal extent of the printed conductor structure 10, the planar printed conductor structure 10 is surrounded by a ferromagnetic core 20. The ferromagnetic core 20 may be formed of any ferromagnetic material.

The planar conductor track structure 10 has, in particular, an upper side 11 and an underside 12 opposite the upper side 11. The top 11 and the Bottom 12 are formed by those sides which have the larger dimensions, in this case consequently the width b, which is significantly greater than the height h. The conductor track structure 10 can be formed, for example, from any electrically conductive material, such as copper.

For example, the planar wiring pattern 10 may be realized as a wiring pattern of a printed circuit. In addition, however, any other planar interconnect structures are possible.

The ferromagnetic core 20, which encloses the planar conductor track structure 10 in a predetermined section, has at least one gap 21. The one or more gaps 21 are arranged in a region A of the upper side 11 and / or the lower side 12. By this is meant that, for example, a virtual imaginary line V, which is perpendicular to the upper side 11 or the lower side 12, passes through the corresponding gap 21.

For example, in FIG. 1, such a virtual line is shown as a dashed line V.

In contrast to FIG. 6, the inductive component 1 expressly has no gap in the region B of the side surfaces, that is to say in the region of the surfaces which connect the top side 11 and the underside 12 to one another.

By the column 21 in the region A of the top 11 and the bottom 12 of the planar conductor pattern 10 arise inhomogeneities in the course of the magnetic field, which the current flow through the planar

Can influence conductor track structure 10. In particular, due to these inhomogeneities in the magnetic field, the current flow is at least partially forced away from the edge in the direction of the middle of the planar conductor track structure 10. This counteracts a possibly occurring skin effect, especially with high-frequency signals, whereby the electric current flow would be forced to the outside. Thus, by targeted positioning and adjustment of the column 21 in the ferromagnetic core 20, an electrical current flow in the planar conductor track structure 10 can be achieved, which also takes place in the inner region of the planar conductor track structure 10. In particular, the electrical current flow away from the edge region into the interior region of the planar conductor track structure 10 be moved. In this way, the current carrying capacity of the planar wiring pattern 10 can be increased.

Optionally, the gap 21 of the ferromagnetic core 20 may be filled with a dielectric filling material 22. The choice of a suitable dielectric filling material 22 can also influence the course of the magnetic field lines and thus the current distribution within the planar conductor track structure 10. If there are a plurality of gaps 21 in the ferromagnetic core 20, the individual gaps 21 can either be filled with the same filling material 22 or, if appropriate, different dielectric filling materials 22 can also be used for the individual gaps 21.

Furthermore, the edges of the ferromagnetic core 20 in the region of the transition to the columns 21 may be rounded.

Figure 2 shows a schematic representation of a cross section through an inductive component 1 according to another embodiment. The embodiment shown in Figure 2 differs from the embodiment described above in particular in that instead of a single gap 21 in the region A of the top 11 and the bottom 12 of the planar

Track structure 10 now several columns 21 are provided. However, the number of four columns shown here is just one example.

In addition, any other number of columns 21 on the top and / or the bottom of the planar conductor track structure 10 is possible. In addition, it should also be noted that column 21, as shown here, both in the region of the top 11 and in the region of the bottom 12 can be attached. In principle, however, it is also possible to provide the column 21 only in the region of the upper side 11 or alternatively only in the region of the lower side 12.

Figure 3 shows a schematic representation of a cross section through an inductive component 1 according to yet another embodiment. The embodiment shown here differs from the previously

described embodiment in particular in that the planar Conductor structure 10 is disposed on an electrically insulating carrier substrate 30. In particular, one side of the planar conductor track structure 10, here in particular the underside 12 of the planar conductor track structure 10, is connected to one side of the carrier substrate 30.

In addition to the embodiment of a planar printed conductor structure 10 shown here, arrangements with a plurality of printed conductors are also possible. For example, planar conductor tracks may be arranged on two opposite sides of the carrier substrate 30. In addition, it is

For example, a layer structure with a plurality of carrier substrates 30 and optionally a plurality of planar conductor tracks possible. It is also possible, if appropriate, to arrange a plurality of conductor tracks as a planar printed conductor structure 10 next to one another on the carrier substrate 30.

Figure 4 shows a schematic representation of a part of an inductive

Component 1 according to another embodiment. As can be seen in the embodiment shown here, the planar

Track structure 10 comprise a plurality of individual tracks 10-i. These individual conductor tracks 10-i can be arranged one above the other, for example. On top of each other in this context, for example, that in each case the underside of a conductor track 10-1 to an upper side of a

adjacent conductor 10-1 points. In addition, the individual conductor tracks 10-i of the conductor track structure 10 may also have different dimensions. For example, the upper two conductor tracks 10-1 and 10-2 have a smaller width than the conductor tracks 10-3 and 10-4 arranged underneath. Furthermore, it is also possible, a plurality of interconnects 10-i in one

common plane next to each other. In this way, for example, a coplanar conductor arrangement 10 can be realized.

As can also be seen in the example according to FIG. 4, the width d 1, d 2 of the column 21 can vary. For example, the width d 1, d 2 of the column 21 can be adapted as a function of the respective interconnect structure 10.

For example, for a larger number of printed conductors 10-i or printed conductors 10-i, for which a higher current density is to be expected, a larger gap width d 1 can be selected, while for a smaller number of Conductor tracks 10-i or a lower expected current density a smaller gap width d2 can be adjusted. In addition, for example, the number of gaps 21 may be varied across the width according to the configuration of the wiring pattern 10. In this way, depending on the characteristics of the planar printed conductor structure 10, the density of the gaps 21 in the ferromagnetic core 20 can be varied.

FIGS. 5a and 5b show a perspective view of an inductive component 1 according to an embodiment. In the partial image 5a, the planar conductor track structure 10 is shown. The planar conductor track structure 10 in this case has several turns. In addition, the partial image 5b shows how the planar printed conductor structure 10 can be enclosed by a ferromagnetic core 20. This ferromagnetic core 20 can

For example, according to the course of the planar conductor track structure 10 have one or more column 21. In this way, the course of the current flow within the planar conductor track structure 10 can be influenced in a targeted manner. Corresponding to the annular course of the strip conductor structure 10 in this embodiment, therefore, the gap 21 of the ferromagnetic core 20 is also designed annular.

The inductive component 1 described above can be used, for example, as an inductive filter element for a high-frequency filter device. Optionally, the inductive component 1 described above for this purpose with other components, such as an ohmic

Resistor and / or a capacitive component can be combined.

In summary, the present invention relates to an inductive component with a planar conductor track structure. The planar track structure is along a given section with a ferromagnetic core

enclosed. For targeted control of the current flow within the planar conductor track structure and in particular the current density in the cross section of the planar conductor track structure, gaps are provided in the ferromagnetic core in a targeted manner. The gaps in the ferromagnetic core are arranged in regions above and / or below the planar conductor track structure.

Claims

claims

An inductive component (1) comprising: a planar wiring pattern (10) comprising a top surface (11) and a bottom surface (12), the top surface (11) being opposite to the bottom surface (12), and a ferromagnetic core (20), which is around the planar

Conductor structure (10) is arranged around, wherein the ferromagnetic core (20) in a region (A) of the

Top (11) and / or the bottom (12) of the planar

Track structure (10) comprises at least one gap (21).

2. Inductive component (1) according to claim 1, wherein the

ferromagnetic core (20) comprises a plurality of gaps (21) which are arranged in the region (A) of the upper side (11) and / or the lower side (12) of the planar printed conductor structure (10).

3. Inductive component (1) according to claim 1 or 2, wherein the planar conductor track structure (10) comprises a plurality of parallel conductor tracks (10-i).

4. Inductive component (1) according to one of claims 1 to 3, wherein the planar conductor track structure (10) comprises a plurality of superposed conductor tracks (10-i).

5. Inductive component (1) according to one of claims 1 to 4, wherein the planar conductor track structure (10) has a plurality of coplanar conductor tracks (10-i). comprises, and wherein in the region (A) of the upper side (11) and / of the underside (12) of each conductor tracks (10-i) at least one gap (21) is arranged.

6. The inductive component according to claim 1, wherein the at least one gap of the ferromagnetic core is filled at least partially with a dielectric filling material.

7. Inductive component (1) according to one of claims 1 to 6, wherein the ferromagnetic core (20) at the transition to the gap (21).

includes rounded edges.

8. Inductive component (1) according to one of claims 1 to 5, wherein the magnetic core (20) in the region of the upper side (11) and / or the underside (12) of the planar conductor track structure (10) comprises a material with ferromagnetic powder particles.

9. Inductive component (1) according to one of claims 1 to 8, with

a carrier substrate (30), wherein the underside (11) and / or the upper side (12) of the planar conductor track structure (10) is arranged on the carrier substrate (30).

10. High-frequency filter device with an inductive component (1) according to one of claims 1 to 9.