TWI785760B - variable capacitor - Google Patents

Abstract

It has a first electrode (1) and a second electrode (2) located at a predetermined distance from each other, and a plurality of electrodes electrically connected between the first electrode (1) and the second electrode (2) respectively. A series circuit (SC1~SC6). Also, in each of the above-mentioned series circuits (SC1-SC6), the dielectric body (3) is connected in series with the semiconductor switches (SW1-SW6) having more than one semiconductor chip opposite to the dielectric body (3). connect. Then, the semiconductor chips (4) of the above-mentioned semiconductor switches (SW1-SW6) are connected to the driving circuits of the respective semiconductor switches (SW1-SW6) by distribution, so that the currents of the above-mentioned series circuits (SC1-SC6) become Open-circuit state or closed-circuit state switching control.

Description

variable capacitor

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

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

The previous capacitor of this Patent Document 1 is provided in a vacuum container (reference numeral 10 in Patent Document 1), and a plurality of concentric cylindrical electrode plates with different diameters are concentrically attached to the fixed electrode mounting conductor. The formed fixed electrode (referred to as 15 in Patent Document 1) is a plurality of cylindrical electrode plates with different diameters that can be inserted and drawn out between the cylindrical electrode plates of the fixed electrode in a non-contact state. A movable electrode (referred to as 16 in Patent Document 1) formed by concentrically attaching to the movable electrode mounting conductor, and a movable lead ( In Patent Document 1, it is coded 10).

According to such a conventional capacitor, by passing through the movable wire, the movable electrode is appropriately moved (in Patent Document 1, the operation part of the symbol 23 is rotated manually or by a motor), so that the fixed electrode and the movable electrode are opposite to each other. area changes. That is, the capacitance (capacitance) generated between the two can be changed to various values. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 8-008142

When changing the electrostatic capacity of the conventional capacitor, the movable electrodes etc. are moved mechanically (physically), so the changing operation is affected by inertia. When the electrostatic capacity is changed, the volume of the vacuum part (vacuum container) will change, so the change operation is also affected by the atmospheric pressure.

That is to say, the conventional capacitor has a mechanically more electrostatic capacitance structure, and a predetermined torque and time are required for the modified operation. From this, it can be estimated that, for example, it is difficult to achieve high speed and high response in the above-mentioned modified operation.

The present invention is made in view of the aforementioned problems, and provides a technology that can contribute to the operability of changing the electrostatic capacity.

The variable capacitor of the present invention contributes to solving the above-mentioned problems, and its one state is provided with: the first electrode and the second electrode are located at positions separated from each other by a predetermined distance; and a plurality of series circuits are respectively Electrically connecting the two of the first electrode and the second electrode, and connecting them in parallel; each of the above-mentioned series circuits is a dielectric body, and has one or more facing the dielectric body. The semiconductor switches of the semiconductor chips are connected in series; the semiconductor chips of the aforementioned semiconductor switches are switched and controlled in such a way that the current of the aforementioned series circuits becomes an open circuit state or a closed circuit state respectively by a driving circuit connected to the respective semiconductor switches.

In addition, in at least two of the above-mentioned series circuits, the electrostatic capacitances of the above-mentioned semiconductor switches in an open state may be different values respectively.

In addition, at least two semiconductor switches may have different numbers of semiconductor chips in each of the aforementioned series circuits.

In addition, in at least two of the aforementioned series circuits, the semiconductor switches may have different areas due to the surface of the semiconductor chip facing the dielectric.

In addition, at least two of the aforementioned series circuits may have dielectrics having different dielectric constants.

In addition, in at least two of the above-mentioned series circuits, the distances of the dielectric bodies in the dielectric system to the direction of the semiconductor wafer may be different from each other.

Moreover, two said 1st electrodes are provided, and said 1st electrodes are located in the position mutually spaced apart by predetermined distance, and said 2nd electrodes may be interposed between said 1st electrodes.

Also, the first electrode may be divided into a plurality of electrode parts, and each of the semiconductor switches may be connected to any one of the electrode parts.

According to the present invention described above, it is possible to contribute to the operability of changing the capacitance.

The variable capacitor according to the embodiment of the present invention is completely different from the conventional capacitor in which the static capacitance is changed by mechanically moving the movable electrodes.

That is, the variable capacitor of the present embodiment includes a first electrode and a second electrode positioned at a predetermined distance from each other, and a plurality of capacitors electrically connected between the first electrode and the second electrode, respectively. series circuit. Also, in each of the aforementioned series circuits, the dielectric body is connected in series to semiconductor switches including one or more semiconductor chips provided to face the dielectric body. Then, in the semiconductor chip of each of the aforementioned semiconductor switches, as a drive circuit connected to each of the semiconductor switches, the current of the aforementioned series circuit is switched and controlled in an open state or a closed state (hereinafter only appropriately referred to as switching control). ) structure.

According to such a structure, the capacitance (capacitance) can be changed to various values by switching and controlling the semiconductor chip of each semiconductor switch by the driving circuit connected to each semiconductor switch. That is to say, the variable capacitor of this embodiment has a structure in which the static capacitance can be changed electrically (digitally), and does not require a predetermined torque and time like previous capacitors. Therefore, compared with conventional capacitors, it is possible to contribute to the operability of changing the electrostatic capacity (for example, speeding up and improving the response of the changing operation of the electrostatic capacity, etc.).

The variable capacitor of this embodiment is suitable for various fields (for example, the field of variable capacitors, the field of semiconductor switches, the field of dielectrics, the field of drive circuits, etc.) etc.), design modifications can be made by appropriately referring to prior art documents, etc. as necessary, and the following Examples 1 to 6 can be cited as one example. In addition, in the following Examples 1 to 6, for example, the same symbols are used for overlapping contents, and detailed descriptions are appropriately omitted. In addition, in the dielectric body in the figure, for the sake of convenience of explanation, the color according to the shade is added.

"Example 1" 1 to 5 illustrate the variable capacitor 10A according to the first embodiment. This variable capacitor 10A is provided with a first electrode 1 and a second electrode 2 which are each in a flat plate shape and are located at a predetermined distance from each other, and are arranged in layers between the first electrode 1 and the second electrode 2 . A plurality of plate-shaped dielectric bodies 3 on one end surface 2a of the second electrode 2 are provided on the surface 3a of the dielectric body 3 at a distance from each other between the first electrode 1 and the dielectric body 3. Semiconductor switches SW (six semiconductor switches SW1 to SW6 in FIG. 1(A) ).

<Structure example of semiconductor switch SW> Then, each semiconductor switch SW is provided with a semiconductor chip 4 including, for example, a semiconductor element including a reverse blocking IGBT and a diode, and the current flowing through the semiconductor switch SW is opened by this semiconductor chip 4. The structure of switching between states or closed-circuit states.

Various aspects are applicable to this semiconductor wafer 4, and it is not specifically limited. For example, when the variable capacitor 10A is used for AC, current can flow in both directions (the current flowing in the direction of the first electrode 1 side and the current flowing in the direction of the second electrode 2 side) in the semiconductor chip 4 . In this case, like the semiconductor wafer 4 shown in FIG. 2 , elements 4 a and 4 b made of, for example, reverse blocking IGBTs are connected in parallel, and the bidirectional current is switched to an open state or a closed state.

Various aspects can be applied to the parallel connection structure of the elements 4a, 4b, and as an example, the structure of the semiconductor wafer 4 as shown in FIG. 3 can be mentioned. In the semiconductor wafer 4 of FIG. 3 , a connection substrate 41 incorporating (not shown in the figure) first and second connection lines is interposed between the elements 4 a and 4 b and the dielectric body 3 . Then, the emitter of element a and the collector of element b are connected by the first connection line, and the collector of element a and the emitter of element b are connected by the second connection line. Furthermore, the second connection line is connected by a connection wiring (lead or the like) W extending between the first electrode 1 and the connection substrate 41 so as to have the same potential as the first electrode 1 .

The semiconductor wafer 4 is provided facing the dielectric body 3 so that a capacitor c described later can be formed between the semiconductor wafer 4 and the dielectric body 3 . For example, in the semiconductor wafer 4 as shown in Figure 3, the bottom surface 40 of the substrate 41 for connection has functions such as terminals, and when a capacitor c described later can be formed between the dielectric body 3, the bottom surface 40 is in contact with the dielectric body 3. It is provided on the surface 3 a of the dielectric body 3 . At this time, the bottom surface 40 becomes a surface facing the dielectric body 3 (hereinafter, it is only appropriately referred to as a facing surface).

By disposing the semiconductor chip 4 in this way, each semiconductor switch SW is connected in series with the dielectric body 3, and forms a capacitor c ( In FIG. 5, capacitors c1 to c4 are formed in the respective semiconductor switches SW1 to SW4) to constitute series circuits SC (in FIG. 1, semiconductor switches SW1 to SW6 constitute series circuits SC1 to SC6). That is, a plurality of series circuits SC are connected in parallel between the first electrode 1 and the second electrode 2 .

The semiconductor switches SW of each series circuit SC are respectively connected to the drive circuits D assigned to the respective series circuits SC (in FIG. 1B , the drive circuits D1 to D3 are respectively connected to the semiconductor switches SW1 to SW3). Thereby, it is comprised so that the control signal for performing opening and closing control can be sent to each semiconductor chip 4 of each semiconductor switch SW.

According to such a structure, by appropriately driving the driving circuit D of each series circuit SC, the current of each series circuit SC (current in both directions in the case of an AC application in FIG. 2 ) can be individually controlled to be switched on and off.

<Structure example of dielectric body 3> In the dielectric body 3 between the first electrode 1 and the second electrode 2 (in Example 5 to be described later, between the second electrode 2 and the third electrode 5), as long as it can insulate the Between the two, when forming the capacitor c shown in FIG. 4 and FIG. 5 , various aspects can be applied, and as an example, a dielectric body 3 formed using a dielectric material such as ceramics or the like can be mentioned.

Also, for example, in the case of the variable capacitor 10A shown in FIG. 1 , one dielectric body 3 is shared in each series circuit SC (the common dielectric body 30 is shared in Embodiments 3 and 4 described later). However, a structure in which an individual dielectric body 3 is provided in each of the series circuits SC may also be used.

As a specific example, first, by processing (cutting, etc.) the planar dielectric body 3 shown in FIG. Dielectric sheet (such as the dielectric body 3 in the shape shown in FIG. 4(A)). Next, a structure in which the above-mentioned dielectric sheets are dispersedly arranged on the one end surface 2 a of the second electrode 2 and the semiconductor switches SW are provided on the respective dielectric sheets can be mentioned.

In addition, for example, in each series circuit SC, a space (not shown) in a vacuum state is formed between the semiconductor switch SW and the second electrode 2. Electron 3 is used together.

<Static Capacitance of Variable Capacitor 10A> The static capacitance of the variable capacitor 10A can be calculated by applying calculation formula (1) described later. Furthermore, the static capacitance (unit F) of the C variable capacitor 10A in the calculation formula (1), the dielectric constant (F/m) of the ε dielectric body 3, and the semiconductor switch SW of the semiconductor switch SW of the S department open circuit state. The total area (unit m ² ) of the area due to the facing surface of the wafer 4 (electrical area: hereinafter only appropriately referred to as the electrical facing area), d is the direction in which the dielectric body 3 faces the semiconductor wafer 4 (hereinafter referred to as the opposite direction as appropriate) distance (in m).

C=ε×S/d ……(1) For example, assuming that the electrical opposing areas of the semiconductor chips 4 of each semiconductor switch SW are respectively Ssw (unit m), when three semiconductor switches SW (such as semiconductor switches SW1-SW3) are in an open state, the formula (1) The total area S is 3Ssw.

Therefore, in the variable capacitor 10A, if the semiconductor switch SW of each series circuit SC is selectively opened and closed, the total area S of the calculation formula (1) can be appropriately changed. That is, the capacitance C of the variable capacitor 10A can be changed and manipulated to various values.

For example, when the electrically opposed areas of the semiconductor switches SW of each series circuit SC have the same value (for example, each Ssw has the same value), the change in capacitance C caused by the switching control of each semiconductor switch SW can be evenly distributed. Amplitude (variable value).

Also, according to this structure, when all of the semiconductor switches SW (all of the semiconductor switches SW1 to SW6 in FIG. 1 ) are in an open state, the charge to the dielectric body 3 passes through the semiconductor chip 4 of all of the semiconductor switches SW. Opposite faces, equally distributed. By distributing the charges in this way, it becomes easy to suppress a temperature rise due to heat concentration that may occur in the dielectric body 3 when the variable capacitor 10A is used.

＜Other＞ In each series circuit SC, various aspects can be applied to the electrical connection of the first electrode 1 and the second electrode 2 (in Embodiment 5 described later, further, the second electrode 2 and the third electrode 5), However, it needs to be connected in a way to reduce floating capacitance. As a specific example, as shown in FIG. 1 and the like, both the semiconductor switch SW side of the series circuit SC and the first electrode 1 are sufficiently spaced apart (for example, arranged with a gap), and connected by wiring W connects the two.

Furthermore, there may be a floating capacitance in the semiconductor switch SW, etc., but if the floating capacitance is relatively small, it can be appropriately ignored.

As described above, according to the structure of the variable capacitor 10A of the first embodiment, the electrostatic capacity of the variable capacitor 10A can be changed to various values, so that a predetermined torque and time are not required like previous capacitors. Thereby, compared with conventional capacitors, it is easy to contribute to the speed-up and high-response of the changing operation of the electrostatic capacity.

"Example 2" In the variable capacitor 10A of the first embodiment, when the types and numbers of the semiconductor chips 4 included in the semiconductor switches SW of the series circuits SC are the same (the electrical opposing areas are the same), the following contents can be obtained.

That is, in the variable capacitor 10A, the range of change in the individual capacitance of each series circuit SC is constant (the range of change in capacitance due to each semiconductor switch SW is constant).

Therefore, the type of variable capacitance of the variable capacitor 10A is determined according to the number of series circuits SC. For example, assuming that the range of change in capacitance of each of the semiconductor switches SW1 to SW4 in the four series circuits SC1 to SC4 shown in FIG. There are 5 types of electrostatic capacity that can be changed during on/off control: "0, 1, 2, 3, 4". In the situation of FIG. 5 , the semiconductor switches SW3 and SW4 are controlled in an open circuit, and the capacitance is "2".

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

Therefore, in the second embodiment, semiconductor switches SW having different numbers of semiconductor chips 4 are applied to the semiconductor switches SW of the respective series circuits SC, and the range of change of the electrostatic capacity due to the respective series circuits SC is set to be different. . Then, by selectively performing on-off control in the driving circuits D allocated to each series circuit SC, the types of variable electrostatic capacitances can be increased.

6 to 8 are used to illustrate the variable capacitor 10B according to the second embodiment. In this variable capacitor 10B, the semiconductor switches SW of each series circuit SC have different numbers of semiconductor chips 4 .

The number of semiconductor chips 4 included in each semiconductor switch SW can be appropriately set, and as an example, a configuration as shown in FIGS. 6 and 7 can be cited.

In the case of the variable capacitor 10B in FIG. 6 , there are one, two, and four semiconductor chips 4 in the semiconductor switches SW1 , SW2 , and SW3 , respectively. That is, in the variable capacitor 10B shown in FIG. 6, there are N semiconductor switches SW, and a structure having ^2N -1 semiconductor chips 4 (N is a natural number greater than or equal to 2, the same applies hereinafter). At this time, assuming that the types and electrically opposed areas of the semiconductor chips 4 are equal, the ratio of the size of the electrically opposed areas of the semiconductor switches SW is 1:2:4:...:(2 ^{N- 1-1} ): (2 ^N-1 ).

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

As described above, in the semiconductor switch SW including a plurality of semiconductor chips 4, various configurations can be applied to the parallel connection structure of the elements 4a, 4b of each semiconductor chip 4, and a configuration as shown in FIG. 8 can be cited as an example.

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

依據該表1，可藉由驅動電路D1～D3的開閉控制來變更之靜電容的種類，係可知有「0、1、2、3、4、5、6、7」的8種類。亦即，圖6的可變電容器10B係可說相對於串聯電路SC(半導體開關SW)為N個，可變更成2 ^N種類的靜電容者。 Here, in the variable capacitor 10B of FIG. 6 , the drive circuits D1 to D3 assigned to the respective series circuits SC1 to SC3 are selectively on-off as shown in Table 1. In addition, the change range of the capacitance of each of the four semiconductor chips of the variable capacitor 10B is set to "1".

According to Table 1, the types of static capacitances that can be changed by the switching control of the drive circuits D1-D3 are known to be 8 types of "0, 1, 2, 3, 4, 5, 6, 7". That is, the variable capacitor 10B in FIG. 6 can be said to be N in number with respect to the series circuit SC (semiconductor switch SW), and can be changed to 2 ^N types of electrostatic capacity.

For example, when it is assumed that the static capacitance is set with an accuracy of about 3% relative to the maximum capacitance, according to the variable capacitor 10B of FIG. Changed to 32 types of static capacitance. That is, it can be seen that the number of drive circuits D can be reduced (from 32 to 5) compared to the variable capacitor 10A of the first embodiment.

As described above, according to the structure of the variable capacitor 10B of the second embodiment, in addition to the same effects as those of the first embodiment, the following effects can also be obtained. That is, compared with the first embodiment, it is possible to change to various types of electrostatic capacitance with a relatively small number of driving circuits D, and it is possible to contribute to miniaturization and high resolution of variable capacitors.

Furthermore, the variable capacitor 10B does not need to be set so that the numbers of the semiconductor chips 4 of the semiconductor switches SW are different in all the series circuits SC, and may be set appropriately. For example, as long as at least two semiconductor switches SW in each series circuit SC have different numbers of semiconductor chips 4, by using the drive circuit D to selectively perform switching control, the same effect as that of the second embodiment can be exerted. Effect.

"Example 3" In the third embodiment, the dielectric bodies 3 of the series circuits SC are configured to have different dielectric constants, and the ranges of change in capacitance due to the series circuits SC are set to be different. Then, by selectively performing on-off control in the driving circuits D allocated to each series circuit SC, the types of variable electrostatic capacitances can be increased.

FIG. 9 is used to illustrate the variable capacitor 10C according to the third embodiment. In the dielectric body 3 of each series circuit SC (shown as three series circuits SC1, SC2, and SC3 in FIG. 9 ) of the variable capacitor 10C, a common dielectric body 30 common to each series circuit SC is laminated. , and the dielectric bodies 31 of different permittivity (in FIG. 9, the dielectric bodies 31a, 31b, and 31c of different permittivity). Thereby, in each series circuit SC, it becomes the structure which has the dielectric body 3 which respectively has a different permittivity.

In the case of the variable capacitor 10C in FIG. 9 , for example, if the variation ranges of the individual capacitances of the series circuits SC1, SC2, and SC3 are set to "α", "β", and "γ", the drive circuit D1 can The type of static capacitance changed by the on-off control of D3 is "0, α, β, γ, α+β, α+γ, β+γ, α+β+γ", which is the same as the variable capacitor in Figure 6 10B is 8 types similarly.

As described above, according to the structure of the variable capacitor 10C of the third embodiment, in addition to the same effects as those of the second embodiment, the following effects can also be obtained. That is, compared with the second embodiment, the number of semiconductor chips 4 of the semiconductor switch SW can be suppressed, so it is possible to contribute to further miniaturization and cost reduction of the variable capacitor.

Furthermore, the variable capacitor 10C does not need to be set so that the dielectric constants of the dielectric bodies 3 are different in all the series circuits SC, and may be set appropriately. For example, as long as the dielectrics 3 of at least two series circuits SC in each series circuit SC are set so as to have different permittivity, the drive circuit D can be used to selectively perform on-off control, and the The same function and effect as in the third embodiment.

"Example 4" In Example 4, the dielectric body 3 of each series circuit SC is configured to have different permittivity in the same manner as in Example 3, and the change in the capacitance of each series circuit SC is changed. Amplitude is set to be different. Then, by selectively performing on-off control in the driving circuits D allocated to each series circuit SC, the types of variable electrostatic capacitances can be increased.

FIG. 10 is used to illustrate the variable capacitor 10D according to the fourth embodiment. In the dielectric body 3 of each series circuit SC (shown as three series circuits SC1, SC2, and SC3 in FIG. 10 ) of the variable capacitor 10D, a common dielectric body 30 common to each series circuit SC is laminated. Dielectric bodies 32 having different sizes in the plane direction of one end face 2a of the second electrode 2 (dielectric bodies 32a and 32b having different sizes in the plane direction of the one end face 2a in FIG. .

In the semiconductor switch SW of each series circuit SC, any one of the surfaces 3 a to 3 c of each step of the dielectric body 3 is provided. Thereby, in each series circuit SC, the distance (the distance between the 2nd electrode 2 and the semiconductor switch SW (semiconductor chip 4)) of the opposing direction of the dielectric body 3 differs in each structure.

In the case of the variable capacitor 10D in FIG. 10 , for example, if the variation ranges of the individual capacitances of the series circuits SC1, SC2, and SC3 are set to "α", "β", and "γ", according to the calculation formula (1) , becomes α≠β≠γ. Furthermore, the types of electrostatic capacitances that can be changed by switching control of the drive circuits D1-D3 are "0, α, β, γ, α+β, α+γ, β+γ, α+β+γ" , the same as the variable capacitor 10B in FIG. 6 has eight types.

As described above, according to the structure of the variable capacitor 10D of the fourth embodiment, in addition to the same effects as those of the third embodiment, the following effects can also be obtained. That is, compared with Example 3, for example, the types of dielectric materials applicable to the dielectric 3 can be reduced or unified, which may contribute to further cost reduction.

Furthermore, the variable capacitor 10D does not need to be set differently in the distance in the opposing direction of all the dielectric bodies 3 in each series circuit SC, and may be set appropriately. For example, as long as the distance in the opposing direction of the dielectric body 3 of at least two series circuits SC in each series circuit SC is set so as to be different from each other, by using the drive circuit D to selectively perform on-off control , the same function and effect as that of Embodiment 4 can be brought into play.

"Example 5" Fig. 11 shows the variable capacitor 10E resulting from Embodiment 5. By interposing the second electrode 2 between the two first electrodes 1 located at a predetermined distance from each other, more series can be formed. Circuit SC. In addition, in the following description, for the convenience of description, one of the two first electrodes 1 is referred to as the "first electrode 1" and the other is referred to as the "third electrode 5" for appropriate description.

In this 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 to the first electrode 1 sandwiching the second electrode 2 .

Between the above-mentioned second electrode 2 and the above-mentioned third electrode 5 is the same as between the first electrode 1 and the second electrode, and the other end surface 2b of the second electrode 2 is laminated with a flat plate-shaped dielectric material. For the dielectric body 3, a plurality of semiconductor switches SW (shown as three semiconductor switches SW4 to SW6 in FIG. 11 ) are provided at a distance from each other.

Thereby, between the second electrode 2 and the third electrode 5, the same as between the first electrode 1 and the second electrode 2, a plurality of series circuits SC (in FIG. SC4～SC6) structure. In addition, a conductor 51 electrically connecting the first electrode 1 and the third electrode 5 is interposed between the two.

As described above, according to the structure of the variable capacitor 10E of the fifth embodiment, in addition to the same effects as those of the first to fourth embodiments, the following effects can also be obtained. That is, compared with Embodiments 1 to 4, for example, the second electrode 2 can be 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, so There is a possibility of contributing to further cost reduction and miniaturization.

Furthermore, in the variable capacitor 10E shown in FIG. 11, between the first electrode 1 and the second electrode 2 and between the second electrode 2 and the third electrode 5, the same number of capacitors (in FIG. 11 3) series circuits SC, however, this number can be appropriately set respectively, 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 the second electrode 2 and the third electrode 5 .

«Embodiment 6» In the first electrode 1 of the variable capacitors 10A to 10E of the embodiments 1 to 5 (the state of the variable capacitor 10E is the first electrode 1 and the third electrode 5), it is not limited to the one shown in each figure. The described one-piece structure, for example, as shown in FIG. 12 and FIG. 13 , can also be applied to a separate structure that is divided into a plurality of electrode parts 1 _SW .

Fig. 12 and Fig. 13 respectively disclose the variable capacitors 10F and 10G caused by the present embodiment 6. In the first electrode 1, there are a plurality of electrode parts 1 _SW (in Fig. 12, they also correspond to the series circuits SC1-SC3 The structure of the electrode part 1 _SW1 ~ 1 _SW3 ).

The electrode portions 1 _SW of the variable capacitors 10F, 10D are arranged separately from the arrangement direction of the series circuits SC (in FIGS. 12 and 13 , they are arranged to face the semiconductor switches SW). The semiconductor switch SW side is connected by a connecting wire W.

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

Also, the number of semiconductor switches SW connected to each electrode portion 1 _SW is not particularly limited, and can be appropriately set. For example, only one semiconductor switch SW is connected to the electrode part 1 _SW of the variable capacitor _10F in FIG. In Fig. 13, it is also possible to connect semiconductor switches SW2, SW3). That is, the side of the semiconductor switch SW of each series circuit SC needs only to be connected to any one of the electrode portions 1 _SW .

As described above, according to the structure 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 effects can also be obtained. That is, compared with Embodiments 1 to 5, for example, the degree of freedom in the design of the first electrode 1 becomes wider, and the assembly of individual constituent elements of the variable capacitors 10F and 10G can be easily carried out, which can contribute to further cost reduction and miniaturization. Possibility to contribute.

In the above, in the present invention, only the described specific examples have been described in detail, but those skilled in the art to which this invention pertains will naturally understand that various changes can be made within the scope of the technical idea of the present invention. Such changes and the like certainly belong to the scope of the patent application. For example, Examples 1 to 6 may be combined appropriately.

1: 1st electrode 1 _SW , 1 _SW1 to 1 _SW3 , 1 _SW23 : electrode part 2: second electrode 2a: one end face 2b: other end face 3: dielectric body 3a to 3c: surface 4: semiconductor wafer 4a, 4b : Element 5: Third electrodes 10A to 10G: Variable capacitor 30: Common dielectric body 31, 31a to 31c, 32, 32a, 32b: Dielectric body 40: Bottom surface 41: Connection substrate 51: Conductor C: Capacitance c, c1～c4: capacitor D, D1～D3: drive circuit SC, SC1～SC6: series circuit SW, SW1～SW6: semiconductor switch IGBT: reverse blocking W: connection wiring

[FIG. 1] Schematic diagram illustrating the structure of a variable capacitor 10A according to Example 1 ((A) is an isolated perspective view, and (B) is a side view of (A) facing both the first electrode 1 and the second electrode 2. sketch of the room).

[FIG. 2] A schematic structural diagram illustrating an example of a semiconductor chip 4 included in the semiconductor switch SW ((A) is a circuit diagram of the semiconductor switch SW, and (B) is an illustration of an element 4a composed of a reverse blocking IGBT, An example circuit diagram of the parallel connection of 4b).

[FIG. 3] A schematic structural diagram illustrating an example of parallel connection of elements 4a, 4b.

[FIG. 4] A schematic structural diagram illustrating an example of the series circuit SC ((A) is a schematic diagram corresponding to the space between the first electrode 1 and the second electrode 2 from the side of FIG. 1(A), (B) System (A) equivalent circuit diagram).

[ FIG. 5 ] An equivalent circuit diagram of a part of the variable capacitor 10A in series circuit SC (four series circuits SC1 to SC4 ).

[FIG. 6] A schematic structural diagram illustrating a variable capacitor 10B according to Example 2 (corresponding to a schematic diagram from the side of FIG. 1(A) facing between the first electrode 1 and the second electrode 2).

[FIG. 7] A schematic structural diagram illustrating another example of the variable capacitor 10B due to Embodiment 2 (corresponding to a schematic diagram from the side surface of FIG. 1(A) facing between the first electrode 1 and the second electrode 2. ). [FIG. 8] A schematic structural diagram illustrating an example of parallel connection of elements 4a, 4b. [FIG. 9] A schematic structural view illustrating a variable capacitor 10C according to Example 3 (corresponding to a schematic view from the side of FIG. 1(A) facing between the first electrode 1 and the second electrode 2). [FIG. 10] A schematic structural diagram illustrating a variable capacitor 10D according to Embodiment 4 (corresponding to a schematic diagram from the side of FIG. 1(A) facing between the first electrode 1 and the second electrode 2). [FIG. 11] A schematic structural view illustrating a variable capacitor 10E according to Embodiment 5 (corresponding to a schematic view from the side of FIG. 1(A) facing between the first electrode 1 and the second electrode 2). [FIG. 12] A schematic structural diagram illustrating a variable capacitor 10F according to Embodiment 6 (corresponding to a schematic diagram from the side of FIG. 1(A) facing between the first electrode 1 and the second electrode 2). [FIG. 13] A schematic structural view illustrating a variable capacitor 10G according to Embodiment 6 (corresponding to a schematic view from the side of FIG. 1(A) facing between the first electrode 1 and the second electrode 2).

1: 1st electrode

2: 2nd electrode

2a: One end face

2b: The other end

3: Dielectric body

3a: Surface

4: Semiconductor wafer

10A: variable capacitor

D1~D3: drive circuit

SC1~SC6: series circuit

SW1~SW6: semiconductor switch

W: Connection wiring

Claims (5)

A variable capacitor, characterized by comprising: a first electrode and a second electrode located at a predetermined distance from each other; and a plurality of series circuits electrically connected to the first electrode and the second electrode respectively. between the two, and connected in parallel between the two; each of the above-mentioned series circuits is connected in series with a dielectric body, and a semiconductor switch with more than one semiconductor chip disposed opposite to the aforementioned dielectric body; each of the aforementioned semiconductor switches The aforementioned semiconductor chip is switched and controlled in such a way that the current of the aforementioned series circuit becomes an open circuit state or a closed circuit state respectively by a drive circuit connected to the respective semiconductor switches; in at least two of the aforementioned series circuits, each of the aforementioned semiconductor switches The electrostatic capacity when it is in an open circuit state is a different value; the aforementioned semiconductor switches have different numbers of semiconductor chips; the aforementioned semiconductor chips of the aforementioned semiconductor switches are of the same type and have the same electrical opposing area. . A variable capacitor, characterized by comprising: a first electrode and a second electrode located at a predetermined distance from each other; and a plurality of series circuits electrically connected to the first electrode and the second electrode respectively. between the two, and connected in parallel between the two; each of the above-mentioned series circuits is connected in series with a dielectric body, and a semiconductor switch with one or more semiconductor chips disposed facing the aforementioned dielectric body; The aforementioned semiconductor chips of the aforementioned semiconductor switches are switched and controlled in such a way that the current of the aforementioned series circuits respectively becomes an open-circuit state or a closed-circuit state by a drive circuit connected to the respective semiconductor switches; , the capacitances of the above-mentioned semiconductor switches when they are in an open state are different values respectively; A plurality of planar dielectrics of different sizes crossing the direction between the two are stacked in the direction between the two to form a ladder shape: each of the above-mentioned planar dielectrics is between the two The thickness in both directions is the same. In the variable capacitor according to claim 2, in at least two of the aforementioned series circuits, the semiconductor switches are provided with different numbers of semiconductor chips. The variable capacitor according to claim 1 or 2, wherein two of the first electrodes are provided, and the first electrodes are located at positions separated from each other by a predetermined distance; the second electrodes are interposed between the first electrodes . The variable capacitor according to claim 1 or 2, wherein the first electrode is divided into a plurality of electrode parts; each of the semiconductor switches is connected to any one of the electrode parts.

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