Variable resistance device

Abstract

To provide a variable resistance device capable of setting a desired resistance value while measuring the resistance value of a variable resistor.SOLUTION: A variable resistance device 100 includes a variable resistor 10 that includes a resistor 11 having a first terminal t1 and a second terminal t2, and a slider 12 having a third terminal t3, and is configured such that a position P at which the slider 12 contacts the resistor 11 is changed, a drive unit 40 for moving and changing the position of the slider 12 as in contact with the resistor 11, an input-side resistance measuring unit 20 for measuring an input-side variable resistance value R1 which is the resistance value between the first terminal t1 and the third terminal t3, and a control unit 30 for controlling the drive unit 40 to change the position at which the slider 12 contacts the resistor 11 based on the input-side variable resistance value R1 measured by the input-side resistance measuring unit 20 when an output-side variable resistance value R2 which is the resistance value between the second terminal t2 and the third terminal t3 is adjusted to a desired output resistance value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a variable resistor device, and more particularly to a variable resistor device including a control unit for adjusting the resistance value of a variable resistor.

Background Art

[0002] Conventionally, a variable resistor device including a control unit for adjusting the resistance value of a variable resistor has been known (see, for example, Patent Document 1).

[0003] In Patent Document 1, in reading a memory card used in a mobile phone or the like, in order to suppress generation of signal noise such as ringing in an interface signal between an IC in the mobile phone and the memory card, a configuration in which a damping resistance control unit adjusts the value of a damping resistance is disclosed. Further, in Patent Document 1, a configuration in which the damping resistance control unit adjusts the resistance value of the damping resistance to match the resistance value stored in a storage unit based on a command to set the damping resistance to a predetermined set value is disclosed. Further, in Patent Document 1, a configuration in which the damping resistance control unit adjusts the damping resistance by gradually decreasing it by a preset value from the maximum resistance value based on a command to set the resistance value of the damping resistance to a predetermined set value is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 discloses a configuration in which a damping resistance control unit adjusts the resistance value of a damping resistance to match the resistance value stored in a storage unit, and a configuration in which the resistance value is adjusted step by step by a set value from a maximum value. Here, in a variable resistor, the resistance value is generally determined by the positional relationship between a resistor body and a slider. However, the state of the variable resistor may change due to deterioration caused by friction of the slider or a change in contact resistance at the contact position, resulting in a deviation in the resistance value. Therefore, it is conceivable that the resistance value adjusted to match the resistance value stored in the storage unit as in Patent Document 1, or the resistance value adjusted by gradually decreasing the resistance value step by step by a set value from the maximum value, may deviate from the desired resistance value. Therefore, a variable resistor device capable of setting the resistance value of a variable resistor to a desired resistance value even when the state of the variable resistor changes is desired.

[0006] The present invention has been made to solve the above problems, and one object of the present invention is to provide a variable resistor device capable of setting the resistance value of a variable resistor to a desired resistance value even when the state of the variable resistor changes.

Means for Solving the Problems

[0007] In order to achieve the above object, a variable resistor device according to one aspect of the present invention includes a resistor body having a first terminal and a second terminal, a slider having a third terminal, a variable resistor configured such that a position where the slider contacts the resistor body is changed, a drive unit that moves and changes the position of the slider that contacts the resistor body, an input-side resistance measurement unit that measures an input-side variable resistance value that is a resistance value between the first terminal and the third terminal, and when adjusting an output-side variable resistance value that is a resistance value between the second terminal and the third terminal to a desired output resistance value, a control unit that controls the drive unit so as to change the position where the slider contacts the resistor body based on the input-side variable resistance value measured by the input-side resistance measurement unit.

[0008] In the variable resistor device according to one aspect of the present invention, as described above, when adjusting the output-side variable resistance value, which is the resistance value between the second terminal and the third terminal, to a desired output resistance value, the control unit controls the drive unit so as to change the position where the slider contacts the resistor based on the input-side variable resistance value measured by the input-side resistance measurement unit. Thereby, since the position of the slider is changed based on the input-side variable resistance value measured by the input-side resistance measurement unit, the resistance value can be adjusted while measuring the actual value of the input-side variable resistance value. As a result, even if the state of the variable resistor changes, the resistance value of the variable resistor can be set to a desired resistance value.

[0009] In the variable resistor device according to the above aspect, preferably, the variable resistor device further includes a storage unit that stores variable resistor relationship information indicating the relationship between the input-side variable resistance value and the output-side variable resistance value. The control unit identifies the input resistance value corresponding to the desired output resistance value based on the variable resistor relationship information acquired from the storage unit in order to adjust the output-side variable resistance value to the desired output resistance value, and controls the drive unit so that the position where the slider contacts the resistor is changed to a position where the measured value of the input-side variable resistance value measured by the input-side resistance measurement unit is equal to the input resistance value. With this configuration, even when it is desired to adjust the output-side variable resistance value among the variable resistance values of the resistor to a desired output resistance value for suppressing signal noise such as ringing, the position where the slider contacts the resistor can be moved to an appropriate position based on the measured value of the input-side variable resistance value. As a result, the output-side variable resistance value can be adjusted to the desired output resistance value based on the measured value of the input-side variable resistance value.

[0010] In the variable resistor device according to the above-described one aspect, preferably, when the control unit adjusts the output-side variable resistance value to a desired output resistance value, during the operation of the load connected to the second terminal t2 of the resistor body, the control unit controls the drive unit to change the position where the slider contacts the resistor body based on the input-side variable resistance value measured by the input-side resistance measurement unit. With this configuration, for example, even when the output-side variable resistance value temporarily changes due to, for example, a shift in the position of the slider caused by vibration during the operation of the load, the output resistance value can be adjusted without stopping the operation of the load.

[0011] In this case, preferably, the variable resistor device further includes a DC cut-off circuit connected between the load operated by the input of AC power and the second terminal t2, and the input-side resistance measurement unit is connected to the first terminal t1 of the resistor body and the third terminal of the slider. Here, generally, DC power is used for resistance measurement. Therefore, with the above configuration, even when the load is driven by AC power, the DC power used for the input-side resistance measurement unit is cut off by the DC cut-off circuit provided between the second terminal and the load, so that it can be prevented from being supplied to the load side. As a result, while operating the load using AC power, the input-side variable resistance value, which is the resistance value between the first terminal of the resistor body and the third terminal of the slider, can be measured and adjusted.

[0012] In the variable resistor device including the above-described DC cut-off circuit, preferably, the variable resistor device further includes an output-side resistance measurement unit connected to the second terminal of the resistor body and the third terminal of the slider for measuring the output-side variable resistance value. With this configuration, even when it is desired to adjust the output-side variable resistance value to a desired output resistance value, the output resistance value can be measured and adjusted.

[0013] In the variable resistor device including the above storage unit, preferably, an output-side resistance measurement unit is further provided which is connected to the second terminal of the resistor body and the third terminal of the slider and measures the output-side variable resistance value. The storage unit stores a plurality of positions where the slider contacts the resistor body, and is configured to update and store the stored variable resistance relationship information based on the measured values of both the input-side variable resistance value and the output-side variable resistance value corresponding to each of the plurality of positions. With this configuration, even if the state of the variable resistor changes (deteriorates) due to wear of the slider or the like, based on the new measured values, the variable resistance relationship information after the change in the resistance characteristics of the variable resistor is updated and stored in the storage unit. As a result, even if the state of the variable resistor changes, the output-side variable resistance value can be appropriately set based on the input-side variable resistance value.

[0014] In this case, preferably, the storage unit is configured to store at least one of the measured values of the input-side variable resistance value and the output-side variable resistance value at each of the plurality of positions. With this configuration, an operator or the like can compare the measured values stored in the storage unit with the current measured values. As a result, an operator or the like can easily find that the resistance characteristics of the variable resistor have changed due to wear of the slider or the like.

[0015] In the variable resistor device including the above storage unit, preferably, the variable resistance relationship information stored in the storage unit includes at least one of a calculation formula for obtaining the output-side variable resistance value based on the input-side variable resistance value, a table for associating the input-side variable resistance value with the output-side variable resistance value, and an approximate formula representing the correlation between the input-side variable resistance value and the output-side variable resistance value. With this configuration, the control unit can easily specify the input resistance value corresponding to the desired output resistance value based on the calculation formula, table, or approximate formula indicating the relationship between the input-side variable resistance value and the output-side variable resistance value stored in the storage unit.

Effects of the Invention

[0016] According to the present invention, as described above, even if the state of the variable resistor changes, it is possible to provide a variable resistor device capable of setting the resistance value of the variable resistor to a desired resistance value.

Brief Description of Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0018] Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings.

[0019] [First Embodiment] With reference to FIG. 1, the configuration of the variable resistor device 100 according to the first embodiment will be described.

[0020] (Configuration of Variable Resistor Device) As shown in FIG. 1, the variable resistor device 100 includes a variable resistor 10, an input-side resistance measurement unit 20, a control unit 30, a drive unit 40, and a capacitor C1 as a DC blocking circuit.

[0021] The variable resistor 10 includes a resistor body 11 having a first terminal t1 and a second terminal t2, and a slider 12 having a third terminal t3. The variable resistor 10 is, for example, a linear potentiometer. The resistor body 11 is made of a conductive film material, and for example, a carbon film that is resistant to wear due to sliding is used. The slider 12 is made of, for example, a conductive metal brush such as a copper alloy, and is provided so as to contact the resistor body 11. Further, the slider 12 has a shaft portion (not shown), and the contact position P (see FIG. 2) with respect to the resistor body 11 is changed by moving the shaft portion supported by the drive unit 40. Note that the shaft included in the slider 12 is made of an insulating material in order to prevent the transmission of noise from the drive unit 40 to the variable resistor 10.

[0022] Here, with reference to FIG. 2, the details of the resistance value of the variable resistor 10 will be described. The resistance value of the entire resistor body 11 is Rz. Here, as described above, the contact position P of the slider 12 with respect to the resistor body 11 is changed. Note that this contact position P indicates the distance from a reference point that is set to 0 at the end on the side where the drive unit 40 is disposed among the positions where the slider 12 can move. At this time, if the resistance value of the first resistor 1 indicating the resistance of the portion of the resistor body 11 on the first terminal t1 side with respect to the contact position P is Rx, and the resistance value of the second resistor 2 indicating the resistance of the portion of the resistor body 11 on the second terminal t2 side with respect to the contact position P is Ry, the relational expression Rz = Rx + Ry holds. This relational expression does not change even if the values of the resistance value Rx of the first resistor 1 and the resistance value Ry of the second resistor 2 are changed according to the contact position P. Note that the resistance value Rx of the first resistor 1 at the contact position P is represented by Rx = (P - P1) / (P2 - P1) × Rz based on the contact position P1 of the slider 12 where the resistance value Rx of the first resistor 1 is the minimum value and the contact position P2 of the slider 12 where the resistance value Rx of the first resistor 1 is the maximum value. Therefore, the resistance value Rx of the first resistor 1 at the contact position P increases as the contact position P of the slider 12 with respect to the resistor body 11 approaches the second terminal t2 side.

[0023] Further, the slider 12 includes the contact resistance 3 between the resistor 11 and the slider 12 at the contact position P and the slider resistance 4 as the resistance value of the slider 12 itself. Let the resistance value of the contact resistance 3 be Rc and the resistance value of the slider resistance 4 be Rs. In this first embodiment, the resistance value Rc of the contact resistance 3 does not change depending on the contact position P between the resistor 11 and the slider 12. Using the above resistance values, the input-side variable resistance value R1, which is the resistance value between the first terminal t1 and the third terminal t3, is represented by the relational expression R1 = Rx + Rc + Rs. Similarly, the output-side variable resistance value R2, which is the resistance value between the second terminal t2 and the third terminal t3, is represented by the relational expression R2 = Ry + Rc + Rs. In this first embodiment, the resistance value Rs and the resistance value Rc are designed to be negligibly small compared to the resistance value Rx and the resistance value Ry. At the initial stage of use of the variable resistance device 100 (the state of the variable resistor 10 has not changed), the relationships R1 ≈ Rx and R2 ≈ Ry hold.

[0024] The input-side resistance measurement unit 20 in FIG. 1 is a measuring device for measuring the input-side variable resistance value R1. The input-side resistance measurement unit 20 includes a comparator 21, a DC current source S, a capacitor C2, and a measurement unit resistor 22 having a resistance value of Rm.

[0025] The comparator 21 has a very large internal impedance compared to the input-side variable resistance value R1 and the resistance value Rm of the measurement unit resistor 22. The comparator 21 is configured to amplify the voltage difference between two wirings connected to the first terminal t1 or the third terminal t3 and transmit a signal to the control unit 30. More specifically, the comparator 21 uses the value obtained by dropping the predetermined output value of the DC current source S by the input-side variable resistance value R1 and the resistance value Rm of the measurement unit resistor 22 to transmit a signal for specifying the input-side variable resistance value R1 to the control unit 30.

[0026] Also, the capacitor C2 included in the input-side resistance measurement unit 20 is connected between two terminals of the comparator 21, and together with the measurement unit resistance 22, it has a function as a low-pass filter circuit for suppressing an external AC signal input to the comparator 21. Note that, for example, a film capacitor is used as the capacitor C2. Also, the measurement unit resistance 22 is provided on one of the wirings on the side connected to the resistor 11 among the wirings connected to the comparator 21, and together with the capacitor C2, constitutes a low-pass filter circuit. Further, the measurement unit resistance 22 is selected to have a value sufficiently larger than the wiring impedance so that the wiring impedance of the wiring connected to the comparator 21 can be ignored, and a value equal to or less than the total resistance value Rz of the resistor 11. Also, for example, a well-known power source for generating a minute DC current is used as the DC current source S.

[0027] The control unit 30 includes a CPU (Central Processing Unit) as a processor, a ROM (Read Only Memory), a RAM (Random Access Memory), a GPU (Graphics Processing Unit), and the like. Also, the control unit 30 includes a storage unit 31. Further, when adjusting the output-side variable resistance value R2, which is the resistance value between the second terminal t2 and the third terminal t3, to a desired output resistance value Ro, the control unit 30 controls the drive unit 40 to change the contact position P where the slider 12 contacts the resistor 11 based on the measured value of the input-side variable resistance value R1, which is the resistance value between the first terminal t1 and the third terminal t3 measured by the input-side resistance measurement unit 20. A detailed description of the control performed by the control unit 30 will be given later.

[0028] The storage unit 31 includes a non-volatile memory and the like, and stores a plurality of contact positions P of the slider 12 with respect to the resistor 11, and the values of the input-side variable resistance value R1 and the output-side variable resistance value R2 for each of the plurality of contact positions P. Also, the storage unit 31 is configured to store variable resistance relationship information indicating the relationship between the input-side variable resistance value R1 and the output-side variable resistance value R2.

[0029] The drive unit 40 supports a shaft portion (not shown) included in the slider 12, and is configured to change the contact position P of the slider 12 with respect to the resistor 11 according to a control command from the control unit 30. The drive unit 40 is, for example, a uniaxial actuator including a servo motor having an encoder, and moves while supporting the shaft of the slider 12, thereby continuously moving the position of the slider 12 to an arbitrary position. Further, the drive unit 40 transmits information on the contact position P of the slider 12 after the movement with respect to the resistor 11 to the control unit 30.

[0030] The capacitor C1 has a function as a DC cutoff circuit, and is configured to cut off DC power flowing to the load 60 (see FIG. 3) side of the variable resistor device 100 via the second terminal t2. As the capacitor C1, for example, a ceramic capacitor is used.

[0031] (Operation of the variable resistor device) Next, the operation of the variable resistor device 100 configured as described above will be described using an example in which the variable resistor device 100 is incorporated in a load drive circuit 200 as shown in FIG. 3.

[0032] As shown in FIG. 3, the load drive circuit 200 includes a power supply 50, a switch Sw1, a switch Sw2, a load 60 driven by AC power, a variable resistor device 100, and a capacitor C3. This load drive circuit 200 is a circuit in which the opening / closing timing and the length of the opening / closing time of the switch Sw1 and the switch Sw2 are controlled to convert DC power output from the power supply 50 into AC power and drive the load 60. At this time, due to the ringing generated when the switch Sw2 is opened / closed, the operation of the load 60 may become unstable. In this first embodiment, in order to stably operate the load 60, for example, a snubber circuit in which the capacitor C3, which is a ceramic capacitor, and the variable resistor device 100 are connected in series is provided in parallel with the switch Sw2 to suppress the ringing generated when the switch Sw2 is opened / closed. More specifically, a case where the output-side variable resistance value R2 is set to a predetermined output resistance value Ro that can reduce the ringing of the switch Sw2 will be described.

[0033] First, the control unit 30 uses an operation unit (not shown) or the like to obtain information that the output-side variable resistance value R2 has been set to the output resistance value Ro by an operator or the like. Here, the desired output resistance value Ro is arbitrarily set by the operator according to the load 60 to which the variable resistance device 100 is connected.

[0034] Next, the control unit 30 calculates the input resistance value Ri corresponding to the desired output resistance value Ro based on the variable resistance relationship information stored in the storage unit 31. Here, in this first embodiment, the variable resistance relationship information is a calculation formula for obtaining the input-side variable resistance value R1 based on the output-side variable resistance value R2. Specifically, the variable resistance relationship information is the calculation formula R1 = Rz + 2Rc + 2Rs - R2. Here, in this first embodiment, Rz, Rc, and Rs are known fixed resistance values. Therefore, when the output-side variable resistance value R2 is the output resistance value Ro, the input resistance value Ri, which is the target value of the input-side variable resistance value R1, is obtained by a calculation formula showing a linear relationship of Ri = Rz + 2Rc + 2Rs - Ro. Note that the variable resistance relationship information is updated at a predetermined timing so as to correspond to the resistance value Rc of the contact resistance 3 and the resistance value Rs of the slider resistance 4 that have changed over time, and is stored in the storage unit 31.

[0035] Next, the control unit 30 starts controlling the drive unit 40 so as to move the position of the slider 12 from the first terminal t1 side to the second terminal t2 side while measuring the input-side variable resistance value R1 by the input-side resistance measurement unit 20. Note that in this first embodiment, this control is performed while the load 60 is operating. The control unit 30 obtains the current input-side variable resistance value R1 based on the signal obtained from the input-side resistance measurement unit 20, and controls the drive unit 40 to change the position of the slider 12 until the input-side variable resistance value R1 becomes the value of the desired input resistance value Ri by feedback control. When the input-side variable resistance value R1 matches the input resistance value Ri, the control unit 30 controls to stop the drive of the drive unit 40 and determines the position of the slider 12 with respect to the resistor 11.

[0036] (Effect of the First Embodiment) Next, the effects of the first embodiment will be described.

[0037] The variable resistor device 100 of the first embodiment includes a resistor 11 having a first terminal t1 and a second terminal t2, and a slider 12 having a third terminal t3. The variable resistor 10 is configured such that the position where the slider 12 contacts the resistor 11 is changed. A drive unit 40 moves and changes the position of the slider 12 that contacts the resistor 11. An input-side resistance measurement unit 20 measures an input-side variable resistance value R1, which is the resistance value between the first terminal t1 and the third terminal t3. When adjusting the output-side variable resistance value R2, which is the resistance value between the second terminal t2 and the third terminal t3, to a desired output resistance value Ro, a control unit 30 controls the drive unit 40 so as to change the position where the slider 12 contacts the resistor 11 based on the input-side variable resistance value R1 measured by the input-side resistance measurement unit 20. As a result, since the position of the slider 12 is changed based on the input-side variable resistance value R1 measured by the input-side resistance measurement unit 20, the input resistance value Ri can be adjusted while measuring the actual value of the input-side variable resistance value R1. Consequently, even if the state of the variable resistor 10 changes, the output-side variable resistance value R2 of the variable resistor 10 can be set to the desired output resistance value Ro.

[0038] In addition, in the first embodiment described above, a storage unit 31 for storing variable resistor relationship information indicating the relationship between the input-side variable resistance value R1 and the output-side variable resistance value R2 is further provided. In order to adjust the output-side variable resistance value R2 to a desired output resistance value Ro, the control unit 30 identifies an input resistance value Ri corresponding to the desired output resistance value Ro based on the variable resistor relationship information acquired from the storage unit 31, and controls the drive unit 40 to change the position where the slider 12 contacts the resistor 11 to a position where the measured value of the input-side variable resistance value R1 measured by the input-side resistance measurement unit 20 is equal to the input resistance value Ri. Thereby, even when it is desired to adjust the output-side variable resistance value R2 to a desired output resistance value Ro for suppressing signal noise such as ringing among the variable resistance values of the resistor 11, the position where the slider 12 contacts the resistor 11 can be moved to an appropriate position based on the measured value of the input-side variable resistance value R1. As a result, the output-side variable resistance value R2 can be adjusted to the desired output resistance value Ro based on the measured value of the input-side variable resistance value R1.

[0039] Also, in the first embodiment described above, when adjusting the output-side variable resistance value R2 to the desired output resistance value Ro, the control unit 30 controls the drive unit 40 to change the position where the slider 12 contacts the resistor 11 based on the input-side variable resistance value R1 measured by the input-side resistance measurement unit 20 during the operation of the load 60 connected to the second terminal t2 of the resistor 11. Thereby, for example, even when the output-side variable resistance value R2 temporarily changes due to a displacement of the slider 12 caused by vibration or the like during the operation of the load 60, the output-side variable resistance value R2 can be adjusted without stopping the operation of the load 60.

[0040] Further, in the above-described first embodiment, a capacitor C1 as a DC cutoff circuit is further provided between a load 60 operated by input of AC power and a second terminal t2, and the input-side resistance measurement unit 20 is connected to a first terminal t1 of a resistor 11 and a third terminal t3 of a slider 12. Thereby, even when the load 60 is driven by AC power, the DC power used for the input-side resistance measurement unit 20 is cut off by the DC cutoff circuit provided between the second terminal t2 and the load 60, so that it can be prevented from being supplied to the load side. As a result, while operating the load 60 using AC power, it is possible to adjust while measuring an input-side variable resistance value R1, which is the resistance value between the first terminal t1 of the resistor 11 and the third terminal t3 of the slider 12.

[0041] Further, in the above-described first embodiment, the variable resistance relationship information stored in the storage unit 31 includes a calculation formula for obtaining an output-side variable resistance value R2 based on the input-side variable resistance value R1. Thereby, the control unit 30 can easily specify an input resistance value Ri corresponding to a desired output resistance value Ro based on the calculation formula showing the relationship between the input-side variable resistance value R1 and the output-side variable resistance value R2 stored in the storage unit 31.

[0042] [Second Embodiment] Next, with reference to FIG. 4, a variable resistance device 110 according to the second embodiment will be described. The device configuration of the variable resistance device 110 according to the second embodiment is the same as the device configuration of the variable resistance device 100 shown in FIG. 1 except that an output-side resistance measurement unit 70 and a switch Sw3 are added. In the second embodiment, descriptions of points common to the first embodiment are omitted.

[0043] As described above, the device configuration of the variable resistor device 110 according to the second embodiment is provided with an output-side resistance measurement unit 70 and a switch Sw3 in addition to the configuration of the variable resistor device 100 according to the first embodiment. The output-side resistance measurement unit 70 includes a configuration equivalent to the input-side resistance measurement unit 20 shown in FIG. 1, and is connected to the second terminal t2 and the third terminal t3 by wiring including the switch Sw3, and measures the output-side variable resistance value R2 between the second terminal t2 and the third terminal t3. The switch Sw3 is controlled by the control unit 30 so as to be open, for example, during the operation of the load 60 connected to the second terminal t2 as shown in FIG. 3, and to be closed only when the output-side resistance measurement unit 70 measures the output-side variable resistance value R2.

[0044] In this second embodiment, unlike the first embodiment, the resistance value Rc of the contact resistance 3 of the variable resistor 10 shown in FIG. 2 changes for each contact position P between the resistor body 11 and the slider 12. Also in this case, as described in the first embodiment, the input-side variable resistance value R1 satisfies the relational expression R1 = Rz + 2Rc + 2Rs - R2. However, even if the target value of the output-side variable resistance value R2 is determined as the output resistance value Ro, since the variable resistance value Rc is included, the input resistance value Ri, which is the target value of the input-side variable resistance value R1, cannot be specified.

[0045] Here, in this second embodiment, the storage unit 31 stores variable resistor relationship information indicating the relationship between the input-side variable resistance value R1 and the output-side variable resistance value R2 without using the above relational expression (without using the variable resistance value Rc). At this time, the storage unit 31 is configured to store a plurality of contact positions P of the slider 12 with respect to the resistor 11. Further, the storage unit 31 is configured to store the past measured values of the input-side variable resistance value R1 and the output-side variable resistance value R2 corresponding to the plurality of contact positions P. That is, the storage unit 31 stores, as variable resistor relationship information, a table that associates the input-side variable resistance value R1 and the output-side variable resistance value R2 for each of the plurality of contact positions P. Specifically, a plurality of contact positions P are stored as coordinate data (Pa, Pb, Pc), the input-side variable resistance value R1 corresponding to the coordinate data of the contact position P is measured as (R1a, R1b, R1c), and the output-side variable resistance value R2 at the position corresponding to the coordinate data of the contact position P is measured as (R2a, R2b, R2c), and these data are stored as a table.

[0046] Further, the storage unit 31 stores, as variable resistor relationship information, an approximate expression representing the correlation between the input-side variable resistance value R1 and the output-side variable resistance value R2 generated based on the above table. Therefore, when the target value of the output-side variable resistance value R2 is set to the output resistance value Ro by an operator or the like, the control unit 30 specifies the input resistance value Ri, which is the target value of the input-side variable resistance value R1, based on the above table or the approximate expression. Thereafter, the control unit 30 controls the drive unit 40 so as to vary the position of the contact position P of the slider 12 with respect to the resistor 11 such that the input-side variable resistance value R1 becomes the input resistance value Ri.

[0047] Further, based on the signals communicated by the input-side resistance measurement unit 20 and the output-side resistance measurement unit 70, the control unit 30 updates and stores in the storage unit 31 the past measured values of the input-side variable resistance value R1 and the output-side variable resistance value R2 corresponding to a plurality of contact positions P at an arbitrary timing. In this second embodiment, the control unit 30 updates and stores in the storage unit 31 as a table the measured values of the input-side variable resistance value R1 and the output-side variable resistance value R2 corresponding to a plurality of contact positions P every time the adjustment of the contact position P of the slider 12 with respect to the resistor 11 is performed 10 times. Further, the control unit 30 is configured to update and store an approximation formula as variable resistance relationship information based on the table of the input-side variable resistance value R1 and the output-side variable resistance value R2 corresponding to a plurality of contact positions P stored in the storage unit 31.

[0048] (Effect of the Second Embodiment) Next, the effects of the second embodiment will be described.

[0049] In the second embodiment described above, an output-side resistance measurement unit 70 that is connected to the second terminal t2 of the resistor 11 and the third terminal t3 of the slider 12 and measures the output-side variable resistance value R2 is further provided. Thereby, even when it is desired to adjust the output-side variable resistance value R2 to a desired output resistance value Ro, it is possible to perform the adjustment while measuring the output resistance value Ro.

[0050] In the second embodiment, the storage unit 31 stores a plurality of positions where the slider 12 contacts the resistor 11, and is configured to update and store the stored variable resistance relationship information based on the measured values of both the input-side variable resistance value R1 and the output-side variable resistance value R2 corresponding to each of the plurality of positions. Thereby, even if the state of the variable resistor 10 changes (deteriorates) due to wear of the slider 12 or the like, the variable resistance relationship information after the change in the resistance characteristics of the variable resistor 10 is updated and stored in the storage unit 31 based on the new measured values. As a result, even if the state of the variable resistor 10 changes, the output-side variable resistance value R2 can be appropriately set based on the input-side variable resistance value R1.

[0051] In the second embodiment described above, the storage unit 31 is configured to store measurement values of at least one of the input-side variable resistance value R1 and the output-side variable resistance value R2 at each of a plurality of positions. Thereby, an operator or the like can compare the measurement values stored in the storage unit 31 with the current measurement values. As a result, it is possible to easily find that the resistance characteristics of the variable resistor 10 have changed due to wear of the slider 12 or the like.

[0052] In the second embodiment described above, the variable resistance relationship information stored in the storage unit 31 includes a table that associates the input-side variable resistance value R1 with the output-side variable resistance value R2, and an approximate expression that represents the correlation between the input-side variable resistance value R1 and the output-side variable resistance value R2. Thereby, the control unit 30 can easily identify the input resistance value Ri corresponding to the desired output resistance value Ro based on the calculation formula, table, or approximate expression indicating the relationship between the input-side variable resistance value R1 and the output-side variable resistance value R2 stored in the storage unit 31.

[0053] Note that other effects of the second embodiment are the same as those of the first embodiment described above.

[0054] [Modification Example] It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown not by the description of the above-described embodiments but by the scope of claims, and further includes all changes (modification examples) within the meaning and scope equivalent to the scope of claims.

[0055] For example, in the first and second embodiments described above, an example in which the storage unit 31 is included inside the control unit 30 is shown, but the present invention is not limited to this. In the present invention, the storage unit 31 may be provided separately from the control unit 30. In that case, a non-volatile memory, a magnetic tape, a hard disk, or the like may be used for the storage unit 31.

[0056] In addition, in the above-described first embodiment, an example in which the variable resistor device 100 is incorporated into the load driving circuit 200 was shown, but the present invention is not limited to this. In the present invention, the variable resistor device 100 is widely applied so as to be incorporated into circuits used for input / output impedance change, frequency adjustment, volume adjustment, output resistance value change, and the like. For example, the variable resistor device 100 may be incorporated into an RC filter circuit, an RLC resonance circuit, a speaker amplifier, a radio transmission circuit, and an ultrasonic pulsar circuit.

[0057] In addition, in the above-described first and second embodiments, an example in which the variable resistor 10 is a linear potentiometer, the resistor body 11 is a carbon film, and the slider 12 is a conductive metal brush such as a copper alloy was shown, but the present invention is not limited to this. In the present invention, any configuration may be used as long as the resistance value of the variable resistor 10 can be adjusted while being measured. The variable resistor 10 may be a rotary potentiometer, the resistor body 11 may be a conductive film other than a carbon film, and the slider 12 may be a conductive metal brush other than a copper alloy.

[0058] In addition, in the above-described first and second embodiments, an example in which the input-side variable resistance value R1 and the output-side variable resistance value R2 have a linear relationship was shown, but the present invention is not limited to this. In the present invention, the input-side variable resistance value R1 and the output-side variable resistance value R2 having a non-linear relationship may be used.

[0059] In addition, in the above-described first and second embodiments, an example in which the capacitor C1 is used as the DC blocking circuit was shown, but the present invention is not limited to this. In the present invention, the DC blocking circuit may use a switch or a relay circuit that is opened at the timing of measuring the input-side variable resistance value R1 by the input-side resistance measuring unit 20.

[0060] In addition, in the first and second embodiments described above, an example in which the input-side resistance measurement unit 20 includes a DC current source S inside has been shown, but the present invention is not limited to this. In the present invention, the input-side resistance measurement unit 20 only needs to include inside a device capable of supplying a constant current. For example, it may be configured to include a DC voltage source.

[0061] In addition, in the first and second embodiments described above, an example in which the drive unit 40 includes a servo motor having an encoder has been shown, but the present invention is not limited to this. In the present invention, for the drive unit 40, a stepping motor that does not include an encoder may be used, or a DC motor or a linear motor may be used.

[0062] In addition, in the first and second embodiments described above, when it is desired to set the output-side variable resistance value R2 to a desired output resistance value Ro, an example has been shown in which the input resistance value Ri corresponding to the output resistance value Ro is specified and the input-side variable resistance value R1 is adjusted while being measured. However, the present invention is not limited to this. In the present invention, for example, in the case of performing impedance matching when the target value of the input-side impedance is known, without determining the target output resistance value Ro of the output-side variable resistance value R2, the target input resistance value Ri of the input-side variable resistance value R1 may be directly set by an operator or the like and used to change the input-side variable resistance value R1.

[0063] In addition, in the first and second embodiments described above, the control unit 30, in order to adjust the output-side variable resistance value R2 to a desired output resistance value Ro, specifies the input resistance value Ri corresponding to the desired output resistance value Ro based on the variable resistance relationship information acquired from the storage unit 31, and changes the position where the slider 12 contacts the resistor 11 to a position where the measured value of the input-side variable resistance value R1 measured by the input-side resistance measurement unit 20 is equal to the input resistance value Ri, and an example has been shown in which the drive unit 40 is controlled. However, the present invention is not limited to this. In the present invention, the control unit 30 may control the drive unit 40 to change the position where the slider 12 contacts the resistor 11 to a position that realizes the desired output resistance value Ro based on, for example, the measurement value of the output-side resistance measurement unit 70 without acquiring the variable resistance relationship information from the storage unit 31.

[0064] Also, in the first and second embodiments described above, when the control unit 30 adjusts the output-side variable resistance value R2 to the desired output resistance value Ro, while the load 60 connected to the second terminal t2 of the resistor body 11 is operating, an example was shown in which the driving unit 40 is controlled to change the position where the slider 12 contacts the resistor body 11 based on the input-side variable resistance value R1 measured by the input-side resistance measurement unit 20. However, the present invention is not limited to this. In the present invention, in a state where the operation of the load 60 is stopped, the position where the slider 12 contacts the resistor body 11 may be changed based on the input-side variable resistance value R1 measured by the input-side resistance measurement unit 20.

[0065] Also, in the first and second embodiments described above, a capacitor C1 as a DC cutoff circuit is further provided between the load 60 operated by the input of AC power and the second terminal t2, and an example was shown in which the input-side resistance measurement unit 20 is connected to the first terminal t1 of the resistor body 11 and the third terminal t3 of the slider 12. However, the present invention is not limited to this. In the present invention, without providing the capacitor C1 as a DC cutoff circuit, in a state where the operation of the load 60 is stopped, the position where the slider 12 contacts the resistor body 11 may be changed.

[0066] Also, in the second embodiment described above, an output-side resistance measurement unit 70 that is connected to the second terminal t2 of the resistor body 11 and the third terminal t3 of the slider 12 and measures the output-side variable resistance value R2 is further provided. The storage unit 31 stores a plurality of contact positions P of the slider 12 with respect to the resistor body 11, and is configured to update and store the stored variable resistance relationship information based on the measured values of both the input-side variable resistance value R1 and the output-side variable resistance value R2 corresponding to each of the plurality of contact positions P. However, the present invention is not limited to this. In the present invention, for example, when the resistance value Rc of the contact resistance 3 is an invariant value, like in the first embodiment, the output-side resistance measurement unit 70 may not be provided, and the variable resistance relationship information corresponding to each of the plurality of contact positions P may not be updated and stored.

[0067] Also, in the above-described second embodiment, an example was shown in which the storage unit 31 is configured to store the measured value of at least one of the input-side variable resistance value R1 and the output-side variable resistance value R2 at each of the plurality of contact positions P. However, the present invention is not limited to this. In the present invention, the measured values of both the input-side variable resistance value R1 and the output-side variable resistance value R2 at each of the plurality of contact positions P may be stored.

[0068] In the above-described second embodiment, an example was shown in which every time the adjustment of the contact position P of the slider 12 with respect to the resistor 11 is performed 10 times, the past measured values of the input-side variable resistance value R1 and the output-side variable resistance value R2 corresponding to the plurality of contact positions P are updated and stored in the storage unit 31 as a table. However, the present invention is not limited to this. In the present invention, the past measured values stored in the storage unit 31 may be updated and stored at any timing. For example, the measured values may be updated and stored in the storage unit 31 as a table at predetermined time intervals or at the timing of activation of the control unit 30.

Explanation of Reference Numerals

[0069] 10 Variable Resistor 11 Resistor 12 Slider 20 Input-Side Resistance Measurement Unit 30 Control Unit 31 Storage Unit 40 Driving Unit 60 Load 70 Output-Side Resistance Measurement Unit 100, 110 Variable Resistance Device t1 First Terminal t2 Second Terminal t3 Third Terminal R1 Input-Side Variable Resistance Value R2 Output-Side Variable Resistance Value

Claims

1. A variable resistor including a resistor having a first terminal and a second terminal, and a slider having a third terminal, wherein the position where the slider contacts the resistor is configured to be changed; A drive unit configured to move and change the position of the slider that contacts the resistor; An input-side resistance measurement unit configured to measure an input-side variable resistance value that is a resistance value between the first terminal and the third terminal; A control unit configured to control the drive unit so that, when adjusting an output-side variable resistance value, which is a resistance value between the second terminal and the third terminal, to a desired output resistance value, the position where the slider contacts the resistor is changed based on the input-side variable resistance value measured by the input-side resistance measurement unit. A variable resistance device comprising:

2. Further comprising a storage unit configured to store variable resistance relationship information indicating a relationship between the input-side variable resistance value and the output-side variable resistance value, The control unit, in order to adjust the output-side variable resistance value to the desired output resistance value, specifies an input resistance value corresponding to the desired output resistance value based on the variable resistance relationship information acquired from the storage unit, and changes the position where the slider contacts the resistor to a position where the measured value of the input-side variable resistance value measured by the input-side resistance measurement unit is equal to the input resistance value. The variable resistance device according to claim 1, wherein the drive unit is controlled.

3. The control unit, when adjusting the output-side variable resistance value to the desired output resistance value, controls the drive unit so that the position where the slider contacts the resistor is changed based on the input-side variable resistance value measured by the input-side resistance measurement unit during operation of a load connected to the second terminal of the resistor. The variable resistance device according to claim 1.

4. Further comprising a DC cut-off circuit connected between the load operated by input of AC power and the second terminal, The input-side resistance measurement unit is connected to the first terminal of the resistor and the third terminal of the slider. The variable resistance device according to claim 3.

5. Further comprising an output-side resistance measurement unit connected to the second terminal of the resistor and the third terminal of the slider and configured to measure the output-side variable resistance value. The variable resistance device according to claim 4.

6. Further comprising an output-side resistance measurement unit connected to the second terminal of the resistor and the third terminal of the slider and configured to measure the output-side variable resistance value, The memory unit stores a plurality of positions where the slider contacts the resistor, and updates and stores the stored variable resistance relationship information based on measurement values of both the input-side variable resistance value and the output-side variable resistance value corresponding to each of the plurality of positions. The variable resistance device according to claim 2.

7. The memory unit is configured to store measurement values of at least one of the input-side variable resistance value and the output-side variable resistance value at each of the plurality of positions. The variable resistance device according to claim 6.

8. The variable resistance relationship information stored by the memory unit includes at least one of a calculation formula for obtaining the input-side variable resistance value based on the output-side variable resistance value, a table for associating the input-side variable resistance value with the output-side variable resistance value, and an approximate formula representing a correlation between the input-side variable resistance value and the output-side variable resistance value. The variable resistance device according to claim 2.

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