Patent Description:
Capacitors are currently used in electric circuits, for instance to filter out noise on signal and power lines. Many other applications are of course possible, including decoupling integrated circuits (sink) from their power supply (source). In this case, capacitors act as a local source of charge, making a (temporary) decoupling from the main source (power supply) possible. In this application, a big capacitance is required to hold more charge.

In some applications however, the use of a plurality of capacitors is required (often in parallel arrangement), for instance when it is sought to form a filter having a broad frequency range (e.g. to filter noise in this broad frequency range).

However, using several capacitors generally result in bulky electric circuits and generate unwanted resonances due to high equivalent series resistance and inductance. Prior art is disclosed in documents <CIT>, <CIT>, <CIT>, <CIT> or <CIT>.

In this context, the invention provides a capacitor assembly according to claim <NUM> comprising:.

wherein the first distance is different from the second distance.

Thus, a capacitor having a first capacitance value is obtained between the first terminal and the second terminal, and another capacitor having a second capacitance value, different from the first capacitance value, is obtained between the first terminal and the third terminal.

In addition, as the same conductive structure (called "main conductive structure" in the following description) is used to form both capacitors, the capacitor assembly is compact and provides low equivalent series resistance and inductance. Since this conductive structure forms a primary plate for the various capacitors of the capacitor assembly, it results in a very low equivalent series inductance value when mounted, and thus in broad band characteristics.

According to possible optional features:.

Other features and advantages of the embodiments of the present invention will be better understood upon reading of preferred embodiments thereof with reference to the appended drawings.

An exemplary embodiment of a capacitor assembly according to the invention as set forth in the appended claims is now described referring in particular to <FIG>.

In the present description, "conductive" should be understood as "electrically conductive".

As clearly visible in <FIG>, this capacitor assembly comprises a main conductive structure <NUM> and a plurality of (here: four) secondary conductive structures <NUM>, <NUM>, <NUM>, <NUM>.

Each conductive structure <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is made of one or several conductive material(s), as further described below.

The main conductive structure <NUM> comprises a wall <NUM> (made of conductive material) from which several sets <NUM>, <NUM>, <NUM>, <NUM> of parallel conductive plates <NUM>; <NUM>; <NUM>; <NUM> extend.

Precisely, each such set <NUM>; <NUM>; <NUM>; <NUM> comprises a plurality of parallel conductive plates <NUM>; <NUM>; <NUM>; <NUM> extending parallel to one another and perpendicular to the wall <NUM>. As visible in <FIG>, each conductive plate <NUM>; <NUM>; <NUM>; <NUM> of these sets <NUM>; <NUM>; <NUM>; <NUM> is affixed to the wall <NUM> along an edge of the concerned conductive plate <NUM>, <NUM>, <NUM>; <NUM>. In the present embodiment, each conductive plate <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM> is thus in electrical contact with (i.e. electrically connected to) the wall <NUM>.

In the present case, some conductive plates <NUM>, <NUM> (here conductive plates <NUM>, <NUM> of sets <NUM>, <NUM>) extend from a first side of the wall <NUM>, while other conductive plates <NUM>, <NUM> (here conductive plates <NUM>, <NUM> of sets <NUM>, <NUM>) extend from a second side of the wall <NUM> (opposite the first side of the wall <NUM>).

According to a possible embodiment, the main conductive structure <NUM> is entirely made of copper. According to another possible embodiment, the wall <NUM> is made of copper and the conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM> are made of nickel.

Neighbouring (parallel) conductive plates <NUM>; <NUM>; <NUM>; <NUM> within a given set <NUM>; <NUM>; <NUM>; <NUM> are separated by the same distance, but this distance varies from one set to another set, as further explained below.

The main conductive structure <NUM> is electrically connected to a terminal <NUM>. For instance, an edge portion <NUM> of the wall <NUM> (protruding here from two sets of parallel conductive plates) is electrically connected to the terminal <NUM>.

The conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the various sets <NUM>, <NUM>, <NUM>, <NUM> are thus in electrical connection with the terminal <NUM>. Said differently, conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the various sets <NUM>, <NUM>, <NUM>, <NUM> are thus conductively connected (within the capacitor assembly) to the terminal <NUM>.

Each secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> comprises a wall <NUM>; <NUM>; <NUM>; <NUM> (made of conductive material) and a set of parallel conductive plates <NUM>; <NUM>; <NUM>; <NUM> extending from this wall <NUM>; <NUM>; <NUM>; <NUM>.

Precisely, each such set comprises a plurality of conductive plates <NUM>; <NUM>; <NUM>; <NUM> parallel to one another and perpendicular to the wall <NUM>; <NUM>; <NUM>; <NUM>. Conductive plates <NUM>; <NUM>; <NUM>; <NUM> of a secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> are affixed to the wall <NUM>; <NUM>; <NUM>; <NUM> of this secondary conductive structure <NUM>; <NUM>; <NUM> and therefore electrically connected to this wall <NUM>; <NUM>; <NUM>; <NUM>.

Within a secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>, the wall <NUM>; <NUM>; <NUM>; <NUM> and the conductive plates <NUM>; <NUM>; <NUM>; <NUM> may be made of the same conductive material, such as copper. However, according to possible embodiments, several conductive materials may be used. For instance, the wall <NUM>; <NUM>; <NUM>; <NUM> may be made of copper, while the conductive plates <NUM>; <NUM>; <NUM>; <NUM> may be made of nickel.

In each secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>, the neighbouring (parallel) conductive plates <NUM>; <NUM>; <NUM>; <NUM> are separated by the same distance, which is thus characteristic of the concerned secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>. The distance between conductive plates <NUM>; <NUM>; <NUM>; <NUM> however varies from one secondary conductive structure to another secondary conductive structure, as further explained below.

Each secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> is electrically connected to a corresponding terminal <NUM>; <NUM>; <NUM>; <NUM>.

In the embodiment shown in <FIG>, the terminals <NUM>, <NUM>, <NUM>, <NUM> are formed by respective conductive blocks (shown in dotted lines) in direct or indirect electrical contact with the wall <NUM>; <NUM>; <NUM>; <NUM> of the concerned secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>.

Such conductive blocks <NUM>; <NUM>; <NUM>; <NUM> are made of a conductive material, for instance copper.

According to a possible implementation (as shown in <FIG> for terminals <NUM>, <NUM>, <NUM>), the terminals (or conductive blocks) <NUM>; <NUM>; <NUM> may be in physical contact with the corresponding wall <NUM>; <NUM>; <NUM> and thus enable (direct) electrical connection between the concerned secondary conductive structure <NUM>; <NUM>; <NUM> and the corresponding terminal <NUM>; <NUM>; <NUM> (and as a consequence between conductive plates <NUM>; <NUM>; <NUM> of each secondary conductive structure <NUM>; <NUM>; <NUM> and the corresponding terminal <NUM>; <NUM>; <NUM>).

According to another possible implementation (as shown in <FIG> for terminal <NUM>), a resistive element <NUM> (such as a resistive block, e.g. made using carbon powder) is interposed between the secondary conductive structure <NUM> and the corresponding terminal <NUM>. In the embodiment shown in <FIG>, the resistive element <NUM> is arranged in physical contact with the wall <NUM> of the secondary conductive structure <NUM> (on one side of the resistive element <NUM>) and with the terminal <NUM> (on the other side of the resistive element <NUM>).

The secondary conductive structure <NUM> and thus the conductive plates <NUM> included in this secondary conductive structure <NUM> are in this case electrically connected to the terminal <NUM> via the resistive element <NUM>.

Conductive plates <NUM>; <NUM>; <NUM>; <NUM> in each secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> is thus conductively connected (within the capacitor assembly) to the corresponding terminal <NUM>; <NUM>; <NUM>; <NUM> within the capacitor assembly.

Each set <NUM>; <NUM>; <NUM>; <NUM> of conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM> interacts with a particular secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>, as now explained.

As visible in <FIG> for the secondary conductive structures <NUM>; <NUM>, conductive plates <NUM>; <NUM>; <NUM>; <NUM> of a given secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> are interleaved with conductive plates of a corresponding set <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM> (conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the concerned secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> being parallel to conductive plates of the corresponding set <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM>).

Thus, each conductive plate <NUM>; <NUM>; <NUM>; <NUM> of a secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> faces a conductive plate <NUM>; <NUM>; <NUM>; <NUM> of the corresponding set <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM>, thereby defining a gap therebetween, which gap is filled with dielectric material.

Although other solutions may be contemplated, a conductive plate <NUM>; <NUM>; <NUM>; <NUM> of a secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> is generally positioned in practice halfway between two conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the corresponding set <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM> (except possibly for conductive plates <NUM>; <NUM>; <NUM>; <NUM> situated at an end of the concerned series of conductive plates).

Correspondingly, a conductive plate <NUM>; <NUM>; <NUM>; <NUM> of a set <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM> is generally positioned in practice halfway between two conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the corresponding secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> (except possibly for conductive plates <NUM>; <NUM>; <NUM>; <NUM> situated at an end of the concerned series of conductive plates).

Thanks to the above construction, conductive plates <NUM>; <NUM>; <NUM>; <NUM> of sets <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM>; <NUM>; <NUM>; <NUM> and conductive plates <NUM>; <NUM>; <NUM>; <NUM> of secondary conductive structures <NUM>; <NUM>; <NUM>; <NUM> form gaps (filled with dielectric material) having a thickness which varies depending on the concerned set <NUM>; <NUM>; <NUM>; <NUM> and secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>.

In the example of <FIG>, conductive plates <NUM> of the secondary conductive structure <NUM> face conductive plates <NUM> of a first set <NUM> (or plurality) of conductive plates of the main conductive structure <NUM> at a fist distance (i.e. conductive plates <NUM> and conductive plates <NUM> are parallel to one another and interleaved, and neighbouring conductive plates <NUM>, <NUM> are separated by the first distance).

Gaps formed between conductive plates <NUM> and conductive plates <NUM> thus have a thickness equal to the first distance and are filled with a first dielectric material.

Conductive plates <NUM> of the secondary conductive structure <NUM> face conductive plates <NUM> of a second set <NUM> (or plurality) of conductive plates of the main conductive structure <NUM> at a second distance (i.e. conductive plates <NUM> and conductive plates <NUM> are parallel to one another and interleaved, and neighbouring conductive plates <NUM>, <NUM> are separated by the second distance).

Gaps formed between conductive plates <NUM> and conductive plates <NUM> thus have a thickness equal to the second distance and are filled with a second dielectric material.

Conductive plates <NUM> of the secondary conductive structure <NUM> face conductive plates <NUM> of a third set <NUM> (or plurality) of conductive plates of the main conductive structure <NUM> at a third distance (i.e. conductive plates <NUM> and conductive plates <NUM> are parallel to one another and interleaved, and neighbouring conductive plates <NUM>, <NUM> are separated by the third distance).

Gaps formed between conductive plates <NUM> and conductive plates <NUM> thus have a thickness equal to the third distance and are filled with a third dielectric material.

Conductive plates <NUM> of the secondary conductive structure <NUM> face conductive plates <NUM> of a fourth set <NUM> (or plurality) of conductive plates of the main conductive structure <NUM> at a fourth distance (i.e. conductive plates <NUM> and conductive plates <NUM> are parallel to one another and interleaved, and neighbouring conductive plates <NUM>, <NUM> are separated by the fourth distance).

Gaps formed between conductive plates <NUM> and conductive plates <NUM> thus have a thickness equal to the fourth distance and are filled with a fourth dielectric material.

In the present example, the same dielectric material is used for filling all the gaps formed between the main conductive structure <NUM> and each secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>. However, in other embodiments, distinct dielectric materials may be used for the gaps formed respectively by the various secondary conductive structures <NUM>; <NUM>; <NUM>; <NUM>.

The interaction between each secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM> and the corresponding set <NUM>; <NUM>; <NUM>; <NUM>; <NUM> of conductive plates <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM> produces a capacitor having a capacitance value C1; C2; C3; C4.

In order to obtain several values C1, C2, C3, C4 of capacitance with the capacitor assembly, gap thicknesses differ depending on the concerned secondary conductive structure - set pair.

Thus, in the example of <FIG>; the first distance, the second distance, the third distance and the fourth distance are not identical.

For instance, at least the first distance is different from the second distance (the difference between the first distance and the second distance being e.g. larger than <NUM>% of the first distance). The third distance is here also different from the first distance, and different from the second distance (the difference between the third distance and the first distance, and/or the difference between the third distance and the second distance being e.g. larger than <NUM>% of the third distance).

Specifically, in the present embodiment, the first distance, the second distance, the third distance and the fourth distance are different two by two (the difference between any two distances among the first, second, third and fourth distances being e.g. larger than <NUM>% of the smallest distance among the first, second, third and fourth distances).

Said differently, the thickness of gaps formed by interaction of a secondary conductive structure with the main conductive structure is different from the thickness of gaps formed by interaction of another secondary conductive structure with the main conductive structure.

Thus, as shown by the electric diagram of <FIG>, the capacitor assembly described above provides several capacitors with distinct respective capacitance values C1, C2, C3, C4. (<FIG> represents the case where no resistive element <NUM> is used.

Precisely, a first capacitance value C1 is obtained between terminal <NUM> and terminal <NUM>, a second capacitance value C2 is obtained between terminal <NUM> and terminal <NUM>, a third capacitance value C3 is obtained between terminal <NUM> and terminal <NUM>, and a fourth capacitance value C4 is obtained between terminal <NUM> and terminal <NUM>.

As the first distance and the second distance are different, the first capacitance value C1 and the second capacitance value C2 are different.

Furthermore, in the present embodiment, as the first distance, the second distance, the third distance and the fourth distance are different two by two, the first capacitance value C1, the second capacitance value C2, the third capacitance value C3 and the fourth capacitance value C4 are also different two by two.

In addition, the capacitance values may also differ from one another due to the use of distinct dielectric materials, as noted above.

As shown in <FIG>, another terminal <NUM> may be provided in electrical connection with the main conductive structure <NUM> (terminal <NUM> being for instance connected to an opposite end of wall <NUM> compared to the connecting point of terminal <NUM> to the wall <NUM>).

<FIG> shows a possible application of the capacitor assembly described above.

In this application, the capacitor assembly is used to damp noise by filtering a voltage signal V carried by a conductive line between a first electronic circuit E1 and a second electronic circuit E2.

In this goal, terminal <NUM> of the capacitor assembly is connected to a pin of the first electronic circuit E1 and terminal <NUM> of the capacitor assembly is connected to a pin of the second electronic circuit E2.

In this application, all terminals <NUM>, <NUM>, <NUM>, <NUM> (electrically connected to the secondary conductive structures <NUM>; <NUM>; <NUM>; <NUM> within the capacitor assembly) are connected to a ground potential (whereto the first electronic circuit E1 and the second electronic circuit E2 are also connected).

This construction makes it possible to filter out noise in a wide range of frequencies, obtained by the concatenation of several frequency ranges respectively corresponding to the various capacitance values C1, C2, C3, C4. The capacitor assembly may thus be used instead of a plurality of capacitors.

This construction is thus particularly compact, which enables in addition to reduce equivalent series resistance (ESR) and equivalent series inductance (ESL).

The invention is not limited to the embodiments described above. In particular, the capacitor assembly may use only <NUM> or <NUM> secondary conductive structures (and corresponding sets of conductive plates in the main conductive structure), or more than <NUM> secondary conductive structures (and corresponding sets of conductive plates in the main conductive structure).

Similarly, the secondary conductive structures may be arranged in a different manner (with respect to the main conductive structure, for instance). In a possible embodiment, the various secondary conductive structures may be arranged in circular fashion around the centre of the main conductive structure, for instance in a star arrangement as shown in <FIG> and <FIG>.

Precisely, in the embodiment shown in <FIG> and <FIG>, the main conductive structure <NUM> includes a plurality of sets <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of (here triangular) conductive plates, these sets <NUM>, <NUM>, <NUM>, <NUM>, <NUM> being arranged around a central connection portion <NUM>.

The central connection portion <NUM> is here in physical contact with (and thus conductively connected to) each of the sets of conductive plates <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The central connection portion <NUM> is also connected to a first terminal <NUM> of the capacitor assembly.

As shown in <FIG>, corresponding secondary conductive structures <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are provided, each conductive structure <NUM>; <NUM>; <NUM>; <NUM>; <NUM> being connected to a terminal <NUM>; <NUM>; <NUM>; <NUM>; <NUM>.

Each secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>; <NUM> includes a plurality of conductive plates (having here a trapezoidal shape in order to cooperate with the triangular conductive plates of the main conductive structure <NUM>).

As in the embodiment of <FIG>, conductive plates of a given secondary conductive structure <NUM>; <NUM>; <NUM>; <NUM>; <NUM> are interleaved with conductive plates of a corresponding set <NUM>; <NUM>; <NUM>; <NUM>; <NUM> of the main conductive structure <NUM>.

The distance between conductive plates is variable from one set of the main conductive structure to another set of the main conductive structure, and, in a similar fashion, from one secondary conductive structure to another secondary conductive structure.

Thus, different gap thicknesses (and hence different capacitances) are obtained for the various secondary conductive structure - set pairs.

Claim 1:
Capacitor assembly comprising:
- a set of terminals comprising at least a first terminal (<NUM>; <NUM>), a second terminal (<NUM>; <NUM>) and a third terminal (<NUM>; <NUM>);
- a conductive structure (<NUM>; <NUM>) comprising a first conductive plate (<NUM>) and a second conductive plate (<NUM>), the first conductive plate (<NUM>) and the second conductive plate (<NUM>) being electrically connected to the first terminal (<NUM>; <NUM>);
- a third conductive plate (<NUM>) electrically connected to the second terminal (<NUM>; <NUM>) and facing the first conductive plate (<NUM>) at a first distance, thereby forming a first gap filled with a first dielectric material; and
- a fourth conductive plate (<NUM>) electrically connected to the third terminal (<NUM>; <NUM>) and facing the second conductive plate (<NUM>) at a second distance, thereby forming a second gap filled with a second dielectric material,
wherein the first distance is different from the second distance.