JP2022073915A - Variable capacitor - Google Patents

Abstract

To provide a technique that can contribute to the operability about a change of electrostatic capacitance.SOLUTION: A variable capacitor includes a first electrode 1 and a second electrode 2 provided apart from each other at a predetermined distance, and a plurality of serial circuits SC1 to SC6 electrically connecting between the first electrode 1 and the second electrode 2. In the serial circuits SC1 to SC6, a dielectric body 3 and semiconductor switches SW1 to SW6 including one or more semiconductor chips provided facing the dielectric body 3 are connected in series. In a semiconductor chip 4 of each of the semiconductor switches SW1 to SW6, a drive circuit assigned and connected to each of the semiconductor switches SW1 to SW6 controls to turn on or off the current of each of the serial circuits SC1 to SC6.SELECTED DRAWING: Figure 1

Description

The present invention relates to a variable capacitor applicable as a capacitor for high voltage and high frequency, for example.

As an example of a variable capacitor applicable as a capacitor for high voltage and high frequency, a variable vacuum capacitor (hereinafter, simply referred to as a conventional capacitor) as shown in Patent Document 1 is known.

The conventional capacitor of Patent Document 1 is a fixed electrode formed by concentrically attaching a plurality of concentric cylindrical electrode plates having different diameters to a fixed electrode mounting conductor in a vacuum vessel (reference numeral 10 in Patent Document 1). (Reference 15 in Patent Document 1) and a plurality of cylindrical electrode plates having different diameters are concentrically attached to the movable electrode mounting conductor so that they can be inserted and removed in a non-contact state between the cylindrical electrode plates of the fixed electrode. A movable electrode (reference numeral 16 in Patent Document 1) and a movable lead (reference numeral 10 in Patent Document 1) for moving the movable electrode from the outside of the vacuum vessel in the axial direction of the cylindrical electrode plate. I have.

According to such a conventional capacitor, the fixed electrode and the movable electrode are moved by appropriately moving the movable electrode via the movable lead (in Patent Document 1, the operation unit of reference numeral 23 is manually or rotated by a motor to move). The facing area between the two changes. That is, it is possible to change the capacitance (capacitor capacity) generated between the two to various values.

Japanese Unexamined Patent Publication No. 8-008142

Conventionally, when the capacitance of a capacitor is changed, the movable electrode or the like is moved mechanically (physically), so that it is considered that the operation related to the change is affected by inertia. Further, since the volume of the vacuum portion (vacuum container) changes when the capacitance is changed, it is considered that the operation related to the change is also affected by the atmospheric pressure.

That is, the conventional capacitor has a configuration in which the capacitance is mechanically changed, and a predetermined torque and time are required for the operation related to the change. As a result, for example, it may be difficult to increase the speed and response in the operation related to the change.

The present invention has been made in view of such technical problems, and an object of the present invention is to provide a technique capable of contributing to operability related to a change in capacitance.

The variable capacitor according to the present invention can contribute to solving the above-mentioned problems, and one aspect thereof is a first electrode and a second electrode located at a predetermined distance from each other, and the first electrode and the first electrode. A plurality of series circuits in which both of the two electrodes are electrically connected to each other and are connected in parallel between the two electrodes are provided, and each of the series circuits is provided with a semiconductor and facing the semiconductor. A semiconductor switch having one or more semiconductor chips is connected in series, and the semiconductor chip of each of the semiconductor switches is turned on by the drive circuit connected to each of the semiconductor switches. It is characterized in that it is switched and controlled so as to be in a state or an off state.

Further, in at least two of the series circuits, the capacitance when the semiconductor switch is on may be a different value.

Further, in at least two of the series circuits, the semiconductor switch may be characterized in that a different number of semiconductor chips are provided.

Further, in at least two of the series circuits, the semiconductor switch may be characterized in that the area of the surface of the semiconductor chip facing the dielectric is different.

Further, at least two of the series circuits may be characterized by having dielectrics having different dielectric constants.

Further, in at least two of the series circuits, the dielectric may be characterized in that the distances in the directions of the dielectric facing the semiconductor chip are different.

Further, it is also characterized in that two first electrodes are provided, the first electrodes are located at a predetermined distance from each other, and the second electrode is interposed between the first electrodes. good.

Further, the first electrode may have a structure separated into a plurality of electrode portions, and each semiconductor switch may be characterized in that it is connected to any of the electrode portions.

As shown above, according to the present invention, it is possible to contribute to the operability related to the change of the capacitance.

Schematic configuration diagram for explaining the variable capacitor 10A according to the first embodiment ((A) is a separated perspective view, (B) is a schematic view facing between both the first electrode 1 and the second electrode 2 from the side of (A). ). A schematic configuration diagram for explaining an example of a semiconductor chip 4 provided in a semiconductor switch SW ((A) is a circuit diagram of a semiconductor switch SW, and (B) is an example of parallel connection of elements 4a and 4b composed of reverse blocking IGBTs. Circuit diagram to explain). The schematic block diagram explaining an example of parallel connection of elements 4a, 4b. A schematic configuration diagram illustrating an example of the series circuit SC ((A) corresponds to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1 (A), and (B) is (B). A) Equivalent circuit diagram). Equivalent circuit diagram of a part of the series circuit SC (four series circuits SC1 to SC4) of the variable capacitor 10A. Schematic configuration diagram illustrating the variable capacitor 10B according to the second embodiment (corresponding to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1A). Schematic configuration diagram illustrating another example of the variable capacitor 10B according to the second embodiment (corresponding to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1A). The schematic block diagram explaining an example of parallel connection of elements 4a, 4b. Schematic configuration diagram illustrating the variable capacitor 10C according to the third embodiment (corresponding to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1A). Schematic configuration diagram illustrating the variable capacitor 10D according to the fourth embodiment (corresponding to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1A). Schematic configuration diagram illustrating the variable capacitor 10E according to the fifth embodiment (corresponding to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1A). Schematic configuration diagram illustrating the variable capacitor 10F according to the sixth embodiment (corresponding to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1A). Schematic configuration diagram illustrating the variable capacitor 10G according to the sixth embodiment (corresponding to a schematic diagram facing between both the first electrode 1 and the second electrode 2 from the side of FIG. 1A).

The variable capacitor according to the embodiment of the present invention is completely different from the conventional capacitor in which a movable electrode or the like is mechanically moved to change the capacitance.

That is, the variable capacitor of the present embodiment has a plurality of series in which the first electrode and the second electrode located at a predetermined distance from each other and the first electrode and the second electrode are electrically connected to each other. It is equipped with a circuit. Further, in each of the series circuits, it is assumed that the dielectric and the semiconductor switch provided with one or more semiconductor chips electrically opposed to the dielectric are connected in series. Then, in the semiconductor chip of each semiconductor switch, switching control is performed so that the current of each series circuit is turned on or off by the drive circuit connected to each semiconductor switch (hereinafter, simply referred to as on / off control). It is a configuration (referred to as appropriate).

According to such a configuration, the drive circuit connected to each of the semiconductor switches can control the on / off of the semiconductor chip of each semiconductor switch to change the capacitance (capacitor capacity) to various values. It will be possible. That is, the variable capacitor of the present embodiment has a configuration in which the capacitance can be changed electrically (digitally), and does not require a predetermined torque or time unlike the conventional capacitor. Therefore, as compared with the conventional capacitor, there is a possibility that it can contribute to the operability related to the change of the capacitance (for example, speeding up of the operation of changing the capacitance, high response, etc.).

The variable capacitor of the present embodiment may have a configuration in which the capacitance can be electrically changed as described above, and may be in various fields (for example, variable capacitor field, semiconductor switch field, dielectric field, drive circuit field, etc.). It is possible to appropriately apply the technical common knowledge of the above and appropriately refer to the prior art documents and the like as necessary to modify the design, and examples 1 to 6 below are given as an example thereof. In the following Examples 1 to 6, detailed description will be omitted as appropriate, for example, by applying the same reference numerals to overlapping contents. Further, the dielectric in the figure is colored by shading for convenience.

<< Example 1 >>
1 to 5 show the variable capacitor 10A according to the first embodiment. The variable capacitor 10A is located between the first electrode 1 and the second electrode 2 which are flat plates and are located at a predetermined distance from each other, and the first electrode 1 and the second electrode 2, respectively, of the second electrode 2. A plurality of flat plate-shaped dielectrics 3 laminated on one end surface 2a and a plurality of the first electrodes 1 and the dielectrics 3 installed on the surface 3a of the dielectric 3 at a distance from each other. The semiconductor switch SW (six semiconductor switches SW1 to SW6 in FIG. 1A) is provided.

<Semiconductor switch SW configuration example>
Each semiconductor switch SW includes a semiconductor chip 4 having a semiconductor element such as a reverse blocking IGBT or a diode, so that the current flowing through the semiconductor switch SW is turned on or off by the semiconductor chip 4. It is configured to switch.

Various aspects of the semiconductor chip 4 can be applied, and the semiconductor chip 4 is not particularly limited. For example, when the variable capacitor 10A is used for alternating current, a current (current flowing in the direction of the first electrode 1 side and a current flowing in the direction of the second electrode 2 side) can flow in both directions in the semiconductor chip 4. In this case, as in the semiconductor chip 4 shown in FIG. 2, for example, elements 4a and 4b made of reverse blocking IGBTs are connected in parallel so that the bidirectional current is switched to an on state or an off state. Can be mentioned.

Various aspects can be applied to the parallel connection configuration of the elements 4a and 4b, and one example thereof is to configure the semiconductor chip 4 as shown in FIG. In the semiconductor chip 4 of FIG. 3, a connection substrate 41 incorporating a first connection line and a second connection line (not shown) is interposed between the elements 4a and 4b and the dielectric 3. Then, the emitter of the element a and the collector of the element b are connected by the first connection line, and the collector of the element a and the emitter of the element b are connected by the second connection line. Further, in the second connection line, the connection wiring (wire or the like) W extending between the first electrode 1 and the connection substrate 41 is connected so as to have the same potential as the first electrode 1. ing.

The semiconductor chip 4 is provided so as to face the dielectric 3 so that the capacitor c described later can be formed between the semiconductor chip 4 and the dielectric 3. For example, in a semiconductor chip 4 as shown in FIG. 3, when the bottom surface 40 of the connection substrate 41 functions as a terminal or the like and a capacitor c described later can be formed between the semiconductor chip 4 and the dielectric material 3, the bottom surface 40 is dielectric. It may be provided in contact with the surface 3a of the body 3. In this case, the bottom surface 40 is a surface facing the dielectric 3 (hereinafter, simply referred to as an facing surface).

By providing the semiconductor chip 4 in this way, in each semiconductor switch SW, the capacitor is connected in series to the dielectric 3 and is connected to the second electrode 2 as shown in the equivalent circuit of FIG. 4 (B). c is formed (in FIG. 5, capacitors c1 to c4 are formed in the semiconductor switches SW1 to SW4), and a series circuit SC is configured (in FIG. 1, the semiconductor switches SW1 to SW6 form the series circuits SC1 to SC6). Become. That is, a plurality of series circuits SC are connected in parallel between both the first electrode 1 and the second electrode 2.

A drive circuit D assigned to each series circuit SC is connected to the semiconductor switch SW of each series circuit SC (in FIG. 1B, drive circuits D1 to D3 are connected to each of the semiconductor switches SW1 to SW3). Has been done. As a result, control signals for on / off control can be transmitted to the semiconductor chip 4 of each semiconductor switch SW.

According to such a configuration, by appropriately driving the drive circuit D of each series circuit SC, the current of each series circuit SC (bidirectional current in the case of the AC application in FIG. 2) is controlled on and off. It becomes possible to do.

<Constituent example of dielectric 3>
In the dielectric 3 between both the first electrode 1 and the second electrode 2 (further between both the second electrode 2 and the third electrode 5 in Example 5 described later), the two are insulated from each other in FIG. 4. , Various embodiments can be applied as long as the capacitor c as shown in FIG. 5 can be formed, and one example thereof is a dielectric 3 made of a dielectric material such as ceramics. Be done.

Further, for example, in the case of the variable capacitor 10A shown in FIG. 1, one dielectric 3 is shared in each series circuit SC (the common dielectric 30 is shared in Examples 3 and 4 described later). An individual dielectric 3 may be provided for each series circuit SC.

As a specific example, first, the flat-plate-shaped dielectric 3 as shown in FIG. 1 is processed into a shape (cutting process, etc.) that matches the semiconductor switch SW of each series circuit SC, so that each of the series circuit SCs has its own shape. A dielectric piece (for example, a dielectric 3 having a shape as shown in FIG. 4A) is formed. Then, each dielectric piece is dispersedly arranged on one end surface 2a of the second electrode 2, and a semiconductor switch SW is provided for each of the dielectric pieces.

In addition, for example, in each series circuit SC, a vacuum state gap portion (not shown) is formed between both the semiconductor switch SW and the second electrode 2, and this gap portion is used as the dielectric 3 as a substitute, or together with the dielectric 3. It is also possible to use them together.

<Capacitance of variable capacitor 10A>
The capacitance of the variable capacitor 10A can be calculated by applying the following equation (1). In the equation (1), C is the capacitance (unit F) of the variable capacitor 10A, ε is the dielectric constant of the dielectric 3 (unit F / m), and S is the semiconductor in the semiconductor switch SW in the ON state. The total area (unit: m ² ) of the area of the chip 4 due to the facing surfaces (electrical area; hereinafter simply referred to as simply the electrical facing area), d is the direction of the dielectric 3 facing the semiconductor chip 4 (hereinafter, hereinafter). , Simply referred to as the opposite direction) (unit: m).

C = ε × S / d …… (1)
For example, assuming that the electrically opposed areas of the semiconductor chips 4 in each semiconductor switch SW are Sw (unit: m), when the three semiconductor switch SWs (for example, semiconductor switches SW1 to SW3) are in the ON state, the equation (1) ) S is 3Sw.

Therefore, if the semiconductor switch SW of each series circuit SC is selectively turned on and off in the variable capacitor 10A, the total area S of the equation (1) can be appropriately changed. That is, it is possible to change the capacitance C of the variable capacitor 10A to various values.

For example, in the semiconductor switch SW of each series circuit SC, when the electrically opposed areas have the same value (for example, the same value in Sw), the change width (variable value) of the capacitance C by the on / off control of each semiconductor switch SW. Can be evenly distributed.

Further, according to such a configuration, when all of the semiconductor switch SWs (all of the semiconductor switches SW1 to SW6 in FIG. 1) are in the ON state, the electric charge for the dielectric 3 is the charge for all the semiconductors of the semiconductor switch SWs. It is evenly distributed through the facing surfaces of the chips 4. By distributing the electric charge in this way, it becomes easy to suppress the temperature rise due to heat concentration that may occur in the dielectric 3 when the variable capacitor 10A is used.

<Others>
In each series circuit SC, various modes can be applied to the electrical connection to the first electrode 1 and the second electrode 2 (further, in the fifth embodiment described later, the second electrode 2 and the third electrode 5). However, it is necessary to connect so as to reduce the stray capacitance. As a specific example, as shown in FIG. 1, the semiconductor switch SW side of the series circuit SC and the first electrode 1 are arranged so as to be sufficiently separated from each other (for example, arranged so as to provide a gap). It is mentioned that both are connected by the connection wiring W.

Although stray capacitance may exist in the semiconductor switch SW or the like, if the stray capacitance is relatively small, it may be ignored as appropriate.

As described above, according to the configuration such as the variable capacitor 10A of the first embodiment, the capacitance of the variable capacitor 10A can be electrically changed to various values, so that a predetermined torque and time are required as in the conventional capacitor. There is no such thing. As a result, it becomes easier to contribute to speeding up the operation of changing the capacitance, increasing the response, etc., as compared with the conventional capacitor.

<< Example 2 >>
In the variable capacitor 10A of the first embodiment, when the types and numbers of the semiconductor chips 4 provided in the semiconductor switch SW in each series circuit SC are the same (the electrical facing areas are the same), the following can be said.

That is, in the variable capacitor 10A, the change width of the capacitance of each series circuit SC is constant (the change width of the capacitance by each semiconductor switch SW is constant).

Therefore, the type of changeable capacitance of the variable capacitor 10A is determined according to the number of series circuits SC. For example, assuming that the change width of the capacitance of each of the semiconductor switches SW1 to SW4 of the four series circuits SC1 to SC4 shown in FIG. 5 is "1", each drive circuit D turns each of the semiconductor switches SW1 to SW4 on and off. When controlling, there are five types of capacitance that can be changed: "0, 1, 2, 3, 4". In the case of FIG. 5, the semiconductor switches SW3 and SW4 are depicted as being turned on, and the capacitance is “2”.

As a result, in the variable capacitor 10A, for example, when setting the capacitance with an accuracy of about 3% with respect to the maximum capacitance, 100/3 ≈ 32 series circuits SC (semiconductor switch SW) are required. Further, if one drive circuit D is assigned to one semiconductor switch SW, 32 drive circuits D are required.

Therefore, in the second embodiment, the semiconductor switch SW of each series circuit SC to which each has a different number of semiconductor chips 4 is applied, and the change width of the capacitance by each series circuit SC is different. .. Then, in the drive circuit D assigned to each series circuit SC, the types of changeable capacitance can be increased by selectively turning on and off.

6 to 8 are for explaining the variable capacitor 10B according to the second embodiment. In the variable capacitor 10B, the semiconductor switch SW of each series circuit SC has a configuration having a different number of semiconductor chips 4.

The number of semiconductor chips 4 included in each semiconductor switch SW can be appropriately set, and one example thereof is the configuration as shown in FIGS. 6 and 7.

In the case of the variable capacitor 10B of FIG. 6, the semiconductor switches SW1, SW2, and SW3 are provided with one, two, and four semiconductor chips 4, respectively. That is, the variable capacitor 10B according to FIG. 6 has a configuration in which the semiconductor switch SW has 2 ^N -1 semiconductor chips 4 with respect to N semiconductor switches (N is a natural number of 2 or more; the same applies hereinafter). In this case, assuming that the types of the semiconductor chips 4 and the electrically opposed areas are the same, the ratio of the sizes of the electrically opposed areas in the respective semiconductor switch SWs is 1: 2: 4: ...: (2). ^N-1 -1): (2 ^N -1).

In the case of the variable capacitor 10B of FIG. 7, the semiconductor switches SW1, SW2, and SW3 are provided with one, two, and three semiconductor chips 4, respectively. In this case, assuming that the types of the semiconductor chips 4 and the electrically opposed areas are the same, the ratio of the sizes of the electrically opposed areas in the semiconductor switches SW1 to SW3 is 1: 2: 3.

In the semiconductor switch SW provided with a plurality of semiconductor chips 4 as described above, various aspects can be applied to the parallel connection configurations of the elements 4a and 4b of each semiconductor chip 4, and the figure is an example thereof. The configuration as shown in 8 can be mentioned.

In the case of the semiconductor switch SW of FIG. 8, the first connection line and the second connection line are built-in (not shown) between the elements 4a and 4b of each semiconductor chip 4 and the dielectric 3 as in FIG. The substrate 41 is interposed. Then, in each semiconductor chip 4, the emitter of the element a and the collector of the element b are connected by the first connection line, and the collector of the element a and the emitter of the element b are connected by the second connection line. Further, in the second connection line, the connection wiring W (wire or the like) extending between the first electrode 1 and the connection substrate 41 is connected so as to have the same potential as the first electrode 1. ing.

Here, in the variable capacitor 10B of FIG. 6, the drive circuits D1 to D3 assigned to the series circuits SC1 to SC3 can be selectively turned on and off as shown in Table 1. The change width of the capacitance of each semiconductor chip 4 of the variable capacitor 10B is set to "1".

According to this Table 1, it can be read that the types of capacitance that can be changed by the on / off control of the drive circuits D1 to D3 are eight types of "0,1,2,3,4,5,6,7". .. That is, it can be said that the variable capacitor 10B of FIG. 6 can be changed to 2 ^N types of capacitance for N series circuits SC (semiconductor switch SW).

For example, assuming that the capacitance is set with an accuracy of about 3% with respect to the maximum capacitance, according to the variable capacitor 10B of FIG. 6, the five semiconductor switch SWs are appropriately selectively turned on / off (5). By controlling with a bit), it is possible to change to 32 types of capacitance. That is, it can be seen that the number of drive circuits D can be reduced (reduced from 32 to 5) as compared with the variable capacitor 10A of the first embodiment.

As described above, according to the configuration such as the variable capacitor 10B of the second embodiment, in addition to the same operation and effect as that of the first embodiment, the following can be said. That is, as compared with the first embodiment, it is possible to change to various types of capacitances with a smaller number of drive circuits D, which may contribute to miniaturization and higher resolution of the variable capacitor.

The variable capacitor 10B does not need to be set so that the number of semiconductor chips 4 in the semiconductor switch SW is different in all of the series circuits SC, and may be set as appropriate. For example, if at least two semiconductor switch SWs in each series circuit SC are provided with different numbers of semiconductor chips 4, the drive circuit D can appropriately selectively turn on and off the semiconductor switches 4 to the second embodiment. It is possible to achieve the same effect.

<< Example 3 >>
In the third embodiment, the dielectric 3 of each series circuit SC is configured to have a different dielectric constant, and the change width of the capacitance by each series circuit SC is different. Then, in the drive circuit D assigned to each series circuit SC, the types of changeable capacitance can be increased by selectively turning on and off.

FIG. 9 is for explaining the variable capacitor 10C according to the third embodiment. The dielectric 3 of each series circuit SC of the variable capacitor 10C (three series circuits SC1, SC2, SC3 are depicted in FIG. 9) has a different dielectric constant from the common dielectric 30 shared by each series circuit SC. 31 (in FIG. 9, dielectrics 31a, 31b, 31c having different dielectric constants) are laminated. As a result, each series circuit SC has a configuration in which the dielectrics 3 having different dielectric constants are provided.

In the case of the variable capacitor 10C of FIG. 9, for example, if the change width of the capacitance of each of the series circuits SC1, SC2, SC3 is "α", "β", and "γ", the drive circuits D1 to D3 are controlled on and off. The types of capacitance that can be changed are "0, α, β, γ, α + β, α + γ, β + γ, α + β + γ", and there are eight types as in the variable capacitor 10B of FIG.

As described above, according to the configuration such as the variable capacitor 10C of the third embodiment, in addition to the same operation and effect as that of the second embodiment, the following can be said. That is, as compared with the second embodiment, the number of semiconductor chips 4 of the semiconductor switch SW can be suppressed, which may contribute to further miniaturization and cost reduction of the variable capacitor.

The variable capacitor 10C does not need to be set so that the dielectric constant of the dielectric 3 is different in all of the series circuits SC, and may be set as appropriate. For example, if the dielectrics 3 of at least two series circuits SC of each series circuit SC are set to have different dielectric constants, the drive circuit D appropriately selectively turns on and off the dielectrics 3 of the present embodiment. It is possible to exert the same action and effect as in 3.

<< Example 4 >>
In the fourth embodiment, the dielectric 3 of each series circuit SC is configured to have a different dielectric constant as in the third embodiment, and the change width of the capacitance by each series circuit SC is different. .. Then, in the drive circuit D assigned to each series circuit SC, the types of changeable capacitance can be increased by selectively turning on and off.

FIG. 10 is for explaining the variable capacitor 10D according to the fourth embodiment. In the dielectric 3 of each series circuit SC of the variable capacitor 10D (three series circuits SC1, SC2, SC3 are depicted in FIG. 10), the common dielectric 30 shared by each series circuit SC and the second electrode 2 Dielectrics 32 having different sizes in the surface direction of one end surface 2a (in FIG. 9, dielectrics 32a and 32b having different sizes in the surface direction of one end surface 2a) are laminated to form a stepped shape. ing.

In the semiconductor switch SW of each series circuit SC, it is provided on any of the surfaces 3a to 3c of each layer of the dielectric 3. As a result, in each series circuit SC, the distance (distance between the second electrode 2 and the semiconductor switch SW (semiconductor chip 4)) in the opposite direction of the dielectric 3 is different from each other. ..

Even in the case of the variable capacitor 10D of FIG. 10, for example, assuming that the change widths of the capacitances of the series circuits SC1, SC2, and SC3 are "α", "β", and "γ", α is according to the equation (1). ≠ β ≠ γ. Further, the types of capacitance that can be changed by on / off control of the drive circuits D1 to D3 are "0, α, β, γ, α + β, α + γ, β + γ, α + β + γ", which is 8 as in the variable capacitor 10B of FIG. It becomes a kind.

As described above, according to the configuration such as the variable capacitor 10D of the fourth embodiment, in addition to the same operation and effect as that of the third embodiment, the following can be said. That is, as compared with Example 3, for example, the types of dielectric materials applied to the dielectric 3 can be reduced or unified, which may contribute to further cost reduction.

The variable capacitor 10D does not need to be set differently at the distances of all the dielectrics 3 of each series circuit SC in the opposite direction, and may be set as appropriate. For example, if the distances of the dielectrics 3 of at least two series circuits SC in the opposite direction of each series circuit SC are set to be different from each other, the drive circuit D may appropriately selectively control the on / off. Therefore, it is possible to obtain the same action and effect as in the fourth embodiment.

<< Example 5 >>
FIG. 11 shows the variable capacitor 10E according to the fifth embodiment, and the number is increased by interposing the second electrode 2 between the two first electrodes 1 located at a predetermined distance from each other. It is possible to configure the series circuit SC of. In the following description, for convenience, one of the two first electrodes 1 will be referred to as the "first electrode 1" and the other will be referred to as the "third electrode 5".

In the variable capacitor 10E, the third electrode 5 is provided at a position separated from the second electrode 2 by a predetermined distance on the opposite side of the first electrode 1 sandwiching the second electrode 2.

Between both the second electrode 2 and the third electrode 5, a flat plate-shaped dielectric 3 is laminated on the other end surface 2b of the second electrode 2, as in the case of both the first electrode 1 and the second electrode. A plurality of semiconductor switches SW (three semiconductor switches SW4 to SW6 are depicted in FIG. 11) are installed at a distance from each other with respect to the dielectric 3.

As a result, between both the second electrode 2 and the third electrode 5, a plurality of series circuits SC (series circuits SC4 to SC6 in FIG. 11) are similarly formed between the first electrode 1 and the second electrode 2. Is connected in parallel. Further, a conductor 51 that electrically connects the first electrode 1 and the third electrode 5 is interposed between the first electrode 1 and the third electrode 5.

As described above, according to the configuration such as the variable capacitor 10E of the fifth embodiment, in addition to exhibiting the same effects as those of the first to fourth embodiments, the following can be said. That is, as compared with Examples 1 to 4, for example, the second electrode 2 is effectively utilized (in FIG. 11, for example, one end surface 2a and the other end surface 2b of the second electrode 2 are utilized) to form a plurality of series circuits SC. Since it can be configured, it may contribute to further cost reduction and miniaturization.

In the variable capacitor 10E of FIG. 11, the same number is used between both the first electrode 1 and the second electrode 2 and between the second electrode 2 and the third electrode 5 (three in FIG. 11). ) Is configured, but the number thereof can be appropriately set and is not particularly limited. For example, one or more series circuits SC may be provided between both the first electrode 1 and the second electrode 2 and between both the second electrode 2 and the third electrode 5.

<< Example 6 >>
The first electrode 1 (in the case of the variable capacitor 10E, the first electrode 1 and the third electrode 5) of the variable capacitors 10A to 10E of Examples 1 to 5 is limited to the one having an integrated structure as described in each figure. For example, as shown in FIGS. 12 and 13, it is possible to apply a separated structure to a plurality of electrode portions 1 _SW .

12 and 13 show the variable capacitors 10F and 10G according to the sixth embodiment, respectively, and the first electrode 1 corresponds to a plurality of electrode portions 1 _SW (corresponding to the series circuits SC1 to SC3 in FIG. 12). It is configured to have the electrode portions 1 _SW1 to 1 _SW3 ).

Each electrode portion 1 _SW of the variable capacitors 10F and 10G is separately arranged in the arrangement direction of each series circuit SC (arranged so as to face the semiconductor switch SW in FIGS. 12 and 13), and the series circuit SC is arranged. The semiconductor switch SW side of the above is connected by the connection wiring W.

Each electrode portion 1 _SW may be electrically connected via, for example, a conductor (common conductor or the like; not shown) arranged on the outer peripheral side of the variable capacitor 10F (or 10G).

Further, the number of semiconductor switch SWs connected to each electrode portion 1 _SW is not particularly limited and can be appropriately set. For example, although one semiconductor switch SW is simply connected to each of the electrode portions 1 _SW of the variable capacitor 10F in FIG. 12, a plurality of semiconductor switches are connected as in the electrode portion 1 _SW23 of the variable capacitor 10G in FIG. SW may be connected (semiconductor switches SW2 and SW3 are connected in FIG. 13). That is, the semiconductor switch SW side of each series circuit SC may be connected to any one of the electrode portions 1 _SW .

As described above, according to the configuration of the variable capacitors 10F and 10G of the sixth embodiment, in addition to the same effects as those of the first to fifth embodiments, the following can be said. That is, as compared with Examples 1 to 5, for example, the degree of freedom in designing the first electrode 1 is widened, and the components of the variable capacitors 10F and 10G can be easily assembled, resulting in further cost reduction and miniaturization. May contribute to.

Although the above description has been made in detail only for the specific examples described in the present invention, it is clear to those skilled in the art that various changes and the like can be made within the scope of the technical idea of the present invention. It goes without saying that such changes belong to the scope of claims. For example, Examples 1 to 6 may be combined as appropriate.

10A to 10G ... Variable capacitor 1, 2, 5 ... 1st, 2nd, 3rd electrode 1 _SW ... Electrode part 3, 30, 31, 32 ... Dielectric 4 ... Semiconductor chip 4a, 4b ... Semiconductor element 51 ... Conductor SW … Semiconductor switch SC… Series circuit W… Connection wiring c… Capacitor

FIG. 10 is for explaining the variable capacitor 10D according to the fourth embodiment. In the dielectric 3 of each series circuit SC of the variable capacitor 10D (three series circuits SC1, SC2, SC3 are depicted in FIG. 10), the common dielectric 30 shared by each series circuit SC and the second electrode 2 Dielectrics 32 having different sizes in the surface direction of one end surface 2a (in FIG. 10 , dielectrics 32a and 32b having different sizes in the surface direction of one end surface 2a) are laminated to form a stepped shape. ing.

Claims (8)

The first electrode and the second electrode, which are located at a predetermined distance from each other,
A plurality of series circuits in which both the first electrode and the second electrode are electrically connected and connected in parallel between the two, respectively.
Equipped with
Each of the series circuits is
Dielectric and
A semiconductor switch having one or more semiconductor chips provided facing the dielectric and a semiconductor switch.
Are connected in series,
The semiconductor chip of each semiconductor switch is a variable capacitor characterized by being switched and controlled so that the current of the series circuit is turned on or off by a drive circuit connected to each of the semiconductor switches. The variable capacitor according to claim 1, wherein in at least two of the series circuits, the capacitances when the semiconductor switches are on are different values. The variable capacitor according to claim 1 or 2, wherein in at least two of the series circuits, the semiconductor switch is provided with a different number of semiconductor chips. The variable capacitor according to any one of claims 1 to 3, wherein in at least two of the series circuits, the semiconductor switch has a different area depending on the surface of the semiconductor chip facing the dielectric. The variable capacitor according to any one of claims 1 to 4, wherein at least two of the series circuits have different dielectric constants. The variable capacitor according to any one of claims 1 to 5, wherein in at least two of the series circuits, the dielectric has a different distance in the direction facing the semiconductor chip in the dielectric. .. Two first electrodes are provided, and each of the first electrodes is located at a predetermined distance from each other.
The variable capacitor according to any one of claims 1 to 6, wherein the second electrode is interposed between the first electrodes. The first electrode has a structure separated into a plurality of electrode portions.
The variable capacitor according to any one of claims 1 to 7, wherein each semiconductor switch is connected to any of the electrode portions.

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