KR20040080727A - Variable inductor capable of preforming continuous inductance variation - Google Patents

Abstract

PURPOSE: A variable inductor is provided to allow the inductor to be adopted to a matching circuit network or an LC resonance circuit network by continuously varying inductance values in accordance with a control signal or a variable signal. CONSTITUTION: A variable inductor comprises an input terminal(110) and an output terminal(150) formed on a substrate(100); inductors(210,230) interposed between the input terminal and the output terminal on the substrate; main paths(190) for serially connecting the inductors; sub paths(300) for directly connecting the main paths between the inductors and the input and output terminals, respectively; and MOSFET switches(350) interposed between the main paths and the sub paths, and which continuously vary inductance values in accordance with the on/off variation of a control voltage.

Description

Variable inductor capable of preforming continuous inductance variation

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to passive element inductors, and more particularly, to a variable inductor capable of continuously varying inductance as a passive element in the form of an integrated circuit.

Passive devices in the form of integrated circuits include resistors, inductors, and capacitors. Conventional integrated circuit passive element inductors are implemented as spiral or meander inductors. In order to change the inductance value in the inductor of this structure, the inductance value can be increased by increasing the number of turns in the spiral form or increasing the size of the spiral at the same number of revolutions. The inductance value can be varied by changing the length of the path). Nevertheless, these types of inductors have an inductance value that is fixed by the shape implemented, ie the number of revolutions and the size of the spiral, or the length of the path, and once the shape is implemented, the inductor is fixed. It has no choice but to have an inductance value.

Nevertheless, in a real network, a more useful effect can be realized when the inductance value is changed, for example, in the case of a resonant network, an extension of a resonance range and a variable matching network can be realized. Accordingly, there is a need for the development of an inductor in the form of an integrated circuit capable of effectively varying the inductance value.

An object of the present invention is to provide a variable inductor in the form of an integrated circuit that can be continuously applied to the inductance value by a control signal or a variable signal, which can be effectively applied to a matching network or an LC resonant network.

Another object of the present invention is to provide an integrated circuit capable of continuously varying inductance values in a circuit using a bond wire as a inductor.

1 is a view schematically illustrating a variable inductor according to a first embodiment of the present invention.

2 is a diagram schematically illustrating a variable inductor according to a second exemplary embodiment of the present invention.

3 is a simulation result schematically shown to explain the effect implemented by the embodiment of the present invention.

4 and 5 are diagrams schematically illustrating variable matching networks to which a variable inductor according to an exemplary embodiment of the present invention may be applied.

FIG. 6A is a diagram schematically illustrating a typical parallel resonant network. FIG.

6B is a diagram schematically illustrating a parallel resonant network to which a variable inductor according to an exemplary embodiment of the present invention is applied.

FIG. 7 is a diagram schematically illustrating a variable inductor according to a third exemplary embodiment of the present invention.

In order to achieve the above technical problem, the entire inductance value can be continuously changed by applying a control signal or a variable signal to a MOSFET switch, so that a matching network or an LC resonant network can be used. Provided is a variable inductor as a passive element in the form of an integrated circuit that can be effectively applied.

The variable inductor may include two terminals implemented on a substrate, a plurality of individual inductors implemented between the two terminals on the substrate, main paths connecting the inductors to each other in series, and Secondary paths directly connecting each of the main paths between the inductors and any one of the terminals, and introduced between each of the main paths between the inductors and each of the sub-paths so that a control voltage is turned on / off By varying the value between (on / off) it can be configured to include MOSFET switches that continuously vary the inductance value.

In addition, the variable inductor is implemented on a substrate on which an output terminal is implemented, the inductor connected to output an output signal to the output terminal, an external input terminal introduced outside the substrate, the external input terminal and the inductor directly A bond wire that connects and implements a constant inductance value thereof, a negative path connected in parallel to the front end of the inductor to connect the bond wire and the output terminal, and between the negative path and the front end of the inductor And a MOSFET switch connected in parallel with the inductor to continuously change the entire inductance value by varying the control voltage to a value between on / off.

In this case, the inductance value may be implemented as an arbitrary inductance value between a maximum value when the switches are all turned off by a selective on or off of the switches and a minimum value when the switches are all turned on.

The arbitrary inductance value is the sum of inductance values from the input terminal side to the inductor connected to the last switched off switch, which is obtained by sequentially turning off some of the switches from one of the input terminals, one of the terminals, and finally It may be the sum of inductance values obtained by adjusting the control voltage of any one or more switches located after the switch is turned off to a value between on and off.

The sub paths and the switches may each be introduced in a number less than the number of the inductors.

According to the present invention, it is possible to provide a variable inductor in the form of an integrated circuit as a passive element that can provide an inductance that is continuously variable according to a control voltage applied to a MOSFET switch.

Hereinafter, the present invention will be described in detail with reference to specific embodiments. However, embodiments of the present invention described may be modified in many different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is to be understood that the embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Therefore, it is preferable to understand that the shape of an element etc. in the drawing are exaggerated in order to emphasize clearer description. Elements denoted by the same reference numerals in the drawings means the same element. In addition, where a layer is described or illustrated as being "on" another layer or substrate, the layer may be in direct contact with the other layer or substrate, or a third layer therebetween. May be interposed.

Embodiments of the present invention provide a variable inductor implemented in the form of an integrated circuit that can continuously vary the inductance value by a control signal or a variable signal. In the variable inductor according to the embodiments of the present invention, a plurality of inductors, which are implemented in a spiral form or meander form as conductors on a substrate, are implemented in series by a main path, and a part of the inductor is partially connected to the main path between the inductors. A negative path is connected that sends the signal directly to the output port without going through the inductor. The connection of this secondary path to the primary path is controlled by a switch. The switch is introduced as a MOSFET switch, which continuously changes the value of the overall inductance by varying the control voltage of the MOSFET switch to a value between on and off.

1 is a view schematically illustrating a variable inductor according to a first embodiment of the present invention.

Referring to FIG. 1, the variable inductor according to the first embodiment of the present invention is implemented as an integrated circuit on a substrate as a passive element, and thus the inductance value is continuously changed. The variable inductor of the present invention is formed in a spiral form of a conductor, for example, aluminum (Al), copper (Cu) or conductive polysilicon or alloys thereof, on a p-type or n-type substrate (100). It is implemented by including the inductors 210 and 230 and the MOSFET switch 350. In FIG. 1, spiral inductors 210 and 230 are represented, but the inductors 210 and 230 may also be implemented in a meander form.

Inductors 210, 230 are introduced between two terminals, that is, input terminal port 110 and output terminal 150. For example, two inductors L1 210 and inductor L2 230 are connected to each other in series by a main path 190 and also to an input terminal 110 and an output terminal 150. The secondary path 300 is connected in parallel to the main path 190 between the two inductors L1 and L2 210 and 230, and the switch 350 is connected to the MOSFET between them. The switch 350 selectively changes the path of the signal from the main path 190 to the sub path 300.

In FIG. 1, the signal is output from the input terminal 110 to the output terminal 150 through the inductor L1 210 and the inductor L2 230 by the operation of the switch 350, or after passing through the inductor L1 210. The output terminal 150 is output through the path 300 and the inductor L2 230 in parallel. The MOSFET switch 350 has a signal passing between the drain and the source, and the passage of the signal is controlled by the gate voltage. That is, the MOSFET switch is controlled by the control voltage.

The signal path is selected by the on and off of the switch 350, and the total inductance value becomes the inductance value of the inductor L1 210 when the switch 350 is turned on. When the inductor L1 210 and the inductor L2 230 has the inductance value. Further, when the voltage of the gate of the switch 350 is a voltage between on and off, the signal passing through the inductor L1 210 passes through the parallel connection circuit of the inductor L2 230 and the sub path 300. The total inductance value has a value that is between the inductance value of the inductor L1 210 and the sum of the inductance values of the inductor L1 210 and the inductor L2 230.

Accordingly, the inductance variable range of the inductor as shown in FIG. 1 has a value between the inductance value of the inductor L1 and the inductance sum of the inductors L1 and L2. In order for the variable inductor to have a value between the inductance value of the inductor L1 210 and the inductance value that is the sum of the inductor L1 210 and the inductor L2 230, the control voltage of the switch 350 is set between the on voltage and the off voltage. Can be set to a value. In this case, the total inductance may be obtained as an arbitrary value between the inductance value of the inductor L1 210 and the inductance value that is the sum of the inductor L1 210 and the inductor L2 230.

2 is a diagram schematically illustrating a variable inductor according to a second exemplary embodiment of the present invention.

The variable inductor according to the second embodiment of the present invention shown in FIG. 2 is an extended form of the first embodiment shown in FIG. 1, and includes an input terminal 110, three inductors L1 210, an inductor L2 230, The inductor L3 250 and the first main path 191 and the second main path 195 connecting each other, the MOSFET first switch 351, the second switch 355, and the first switch 351. And a second part path 305, which can be selected by the second part path 301, and a second part path 305, which can be selected by the second switch 355.

The signal passing through the input terminal 110 by the operation of the first switch 351 and the second switch 355 is directly output to the output terminal 150 via the inductor L1 210 and the first secondary path 301. Or the signal passing through the input terminal 110 is output to the output terminal 150 via the inductor L1 210, the inductor L2 230 and the second sub path 305, or the signal passing through the input terminal 110. May be output to the output terminal 150 via the inductor L1 210, the inductor L2 230, and the inductor L3 250. At this time, when an operation of the switches 351 and 355 is performed such that the first switch 351 is turned on and the second switch 355 is turned off, the signal is connected to the inductor L1 210 and the first sub path 301. Pass through the output terminal 150. In addition, when the first switch 351 is turned off and the second switch 355 is turned on, the signal passes through the inductor L1 210, the inductor L2 230, the sub path 305, and the output terminal 150. . In addition, when the first switch 351 is turned off and the second switch 355 is turned off, the signal passes through the inductor L1 210, the inductor L2 230, the inductor L3 250, and the output terminal 150. .

The variable range of inductance of the variable inductor shown in FIG. 2 has a value between the sum of three inductors L1, L2, and L3 in the inductance value of the inductor L1, similarly described with reference to FIG. Specifically, for example, in order for the variable inductor to have a value between the inductance value of the inductor L1 210 and the inductance value which is the sum of the inductor L1 210 and the inductor L2 230, the second switch 355 is turned on and the second switch 355 is turned on. The control voltage of the one switch 351 may be set to a value between the on voltage and the off voltage. In this way, any value between the inductance value of the inductor L1 210 and the inductance value that is the sum of the inductor L1 210 and the inductor L2 230 can be obtained as the inductance value of the variable inductor.

In addition, the variable inductor is the total inductance between the inductance value of the sum of the inductors L1 210 and the inductor L2 230 and the sum of the inductance values of the inductors L1 210 and the inductor L2 230 and the inductor L3 250. In order to have a value, the first switch 351 may be turned off and the voltage of the second switch 355 may be set to a value between the on voltage and the off voltage. In this manner, an arbitrary value between the sum of inductance values of the inductor L1 210 and the inductor L2 230 and the sum of the inductance values of the inductor L1 210 and the inductor L2 230 and the inductor L3 250 is determined. Can be obtained with the total inductance value.

3 is a simulation result schematically shown to explain the effect implemented by the embodiment of the present invention.

Referring to FIG. 3, the results of simulating the structure depicted in FIG. 1 to demonstrate the variable capability of inductance that can be implemented by the variable inductor according to an embodiment of the present invention are shown in FIG. 3. . In the variable inductor structure shown in FIG. 1, inductor L1 210 and inductor L2 230 are configured as rectangular spiral inductors. The spiral inductor has an inductance value determined as the number of turns, and each of the inductors having a rotational speed of 2.5 has a value of about 2 nH in the 2.4 GHz band.

In the simulation results of FIG. 3, when the control voltage of the switch (350 in FIG. 1) (ie, the gate voltage of the MOSFET) is between approximately 0V to 0.4V to keep the switch 350 off, both inductors L1. The sum of inductances of L2 (210, 230) is indicated by a value of approximately 4 nH. This proves that since the path of the signal passes through L1 210 and L2 230, the sum of the two inductances is the total inductance value of the variable inductor. When the control voltage is varied from 0.4V to 1.2V, the value of inductance is varied in the range of 4nH to 2nH in FIG. 3. This proves that the signal is output to the output terminal 150 via the inductor L1 210 and simultaneously through the inductor L2 230 and the negative path 300, and the variable inductor may continuously vary the inductance value by the variable control voltage. Prove that you can.

As such, the variable inductor according to the embodiments of the present invention as shown in FIGS. 1 and 2 may be configured to include N inductors (eg, spiral or meander shapes). At this time, a plurality of secondary paths for directly sending a signal to an output terminal without passing through some of the inductors, and the primary path connecting the inductors and the secondary paths, that is, between the inductors and Multiple MOSFET switches connecting the negative paths can each be configured with N-1.

As described above, in the variable inductor composed of N unit inductors, an arbitrary inductance value between the maximum value of the inductance values of the N inductors and the lowest value of the smallest inductance value may be obtained. This arbitrary inductance value causes the voltage of the plurality of MOSFET switches to be turned off in turn from the input terminal side to obtain an inductance value equal to the sum of the inductances of the unit inductors to which the switch last off from the input terminal is connected, and last from the input terminal. This can be achieved by adjusting the control voltage of one or more MOSFET switches to a value between on and off from the switch off.

The variable inductor according to embodiments of the present invention may be applied to a variable matching network or an LC resonant network.

4 and 5 are diagrams schematically illustrating variable matching networks to which a variable inductor according to an exemplary embodiment of the present invention may be applied.

4 and 5, the variable inductor according to the embodiment of the present invention may be applied to a variable matching network as a passive element. In the high frequency circuit, if there is an impedance mismatch using L, Pi (??) type network, a matching network can be inserted between them to implement a matching circuit without signal reflection. In L, Pi (??) type matching network, the variable inductor can be used to construct the matching network.

Referring to FIG. 4, the components of the matching network configured between the input terminal 411 and the output terminal 415, for example, reference numerals 431, 433, and 435, use a variable capacitance or inductor. The value of the element becomes a design variable to create a matching network that matches the input and output impedances. In the case of the Pi type, the network is composed of three element values used in the network. In this case, the variable inductor according to the embodiment of the present invention may be applied to the inductors used as the elements.

Referring to FIG. 5, design elements include two elements between an input terminal 511 and an output terminal 515 used in the case of an L-type network, that is, reference numerals 531 and 535 of FIG. It may be configured as a capacitor. In this case, the variable inductor according to the embodiment of the present invention may be adopted for the inductor. The values of these elements become design variables, enabling the matching network to match the impedance to be matched.

FIG. 6A is a diagram schematically illustrating a typical parallel resonant network. FIG.

6B is a diagram schematically illustrating a parallel resonant network to which a variable inductor according to an exemplary embodiment of the present invention is applied.

Referring to FIG. 6B, the variable inductor according to the embodiment of the present invention may be applied to a typical parallel LC resonant network as shown in FIG. 6A as shown in FIG. 6B. A typical LC resonant circuit is composed of a fixed inductor L and a variable capacitor C as shown in FIG. 6A, and the range of the resonant frequency is adjusted by the variable capacitor. In contrast, the LC resonant circuit according to the embodiment of the present invention illustrated in FIG. 6B is configured by connecting the variable inductor L and the variable capacitor C in parallel. In the LC resonant circuit using the variable inductor according to the exemplary embodiment of the present invention, since the inductance and capacitance values are changed by the control signal, the resonance range of the resonant frequency is wider than that of the conventional fixed inductor and the variable capacitor. .

FIG. 7 is a diagram schematically illustrating a variable inductor according to a third exemplary embodiment of the present invention.

Although the variable inductors according to the exemplary embodiments of the present invention described above are all integrated and formed in an integrated circuit form on a substrate as illustrated in FIG. 1 and the like, a spiral or meander formed on the substrate by introducing an input terminal to the outside of the substrate The variable inductor may be configured by connecting an inductor having a shape and an external input terminal with a bond wire.

Referring to FIG. 7, a second inductor 270 having a spiral or meander shape integrated in the form of an integrated circuit is formed on a substrate 100, and the second inductor 270 and an external input terminal formed externally ( 111 may be directly connected to the bond wire 400. In this case, the bond wire 400 is used to connect the semiconductor substrate 100 and the input terminal 111 of the package. The bond wire 400 itself not only acts as an electrical connection, but also plays a role in realizing a certain value of inductance in the high frequency circuit itself. That is, the bond wire 400 acts as the first inductor L1. At this time, the value of a constant inductance is determined by the length of the bond wire 400. When it is necessary to vary the inductance value of a kind of inductor implemented by the bond wire 400, since the length of the bond wire 400 once implemented cannot be changed, the inductance value cannot be substantially changed. However, as shown in FIG. 7, a circuit in the form of an integrated circuit is added to the substrate 100 to introduce a second inductor 270 implemented in the form of the integrated circuit. As described above, the MOSFET switch 350 and the sub path are described. By introducing 300, the total inductance value can be varied by controlling the MOSFET switch 350.

Therefore, in the variable inductor illustrated in FIG. 7, the second inductor 270 is implemented on the substrate 100 on which the output terminal 150 is implemented, and the external input terminal 111 and the second input terminal introduced outside the substrate 100. Inductor L2 270 is directly connected to bond wire 400. In parallel to the front end of the second inductor 270, the sub-path 300 is connected similarly as described with reference to FIG. 1, and by the MOSFET switch 350 connected in parallel to the second inductor 270, the total inductance The value is variable. That is, as described above, the control voltage (that is, the gate voltage) of the MOSFET switch 350 may be continuously changed to a value between on / off and thus the total inductance value may be continuously changed.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to this, It is clear that the deformation | transformation and improvement are possible by the person of ordinary skill in the art within the technical idea of this invention.

According to the present invention as described above, it is possible to implement a variable inductor whose inductance value is continuously changed by a control signal applied to the MOSFET switch. The variable inductor may be applied to implement a matching circuit or a resonant circuit to improve the performance of the resonant circuit or the matching circuit.

Claims (5)

Two terminals implemented on the substrate; A plurality of individual inductors implemented between the two terminals on the substrate; Main paths connecting the inductors with each other in series; Secondary paths directly connecting each of the primary paths between the inductors and any one of the terminals; And It is introduced between each of the main paths and each of the sub-paths between the inductors, the MOSFET to continuously change the inductance value by varying the control voltage to a value between on / off ( MOSFET) switches. The method of claim 1, And the inductance value is implemented as any inductance value between the maximum value when the switches are all off by the selective on or off of the switches and the minimum value when the switches are all on. The method of claim 2, The arbitrary inductance value is the sum of inductance values from the input terminal side, which is one of the terminals, to the inductor connected to the last switched off switch, which is obtained by turning off some of the switches in turn. And a sum of inductance values obtained by adjusting a control voltage of any one or more switches positioned after the last off switch to a value between on and off. The method of claim 1, And the sub paths and the switches are each introduced with a number less than the number of the inductors. An inductor implemented on a substrate on which an output terminal is implemented and connected to output an output signal to the output terminal; An external input terminal introduced outside the substrate; A bond wire which directly connects the external input terminal and the inductor and implements a constant inductance value by itself; A negative path connected in parallel with the front end of the inductor to connect the bond wire and the output terminal; And MOSFET connected in parallel to the inductor between the negative path and the front end of the inductor to continuously change the entire inductance value by varying a control voltage to a value between on and off. A variable inductor comprising a switch.