JP2020088829A - Triangular wave output circuit, PWM signal output circuit, drive circuit, and mechanical load generator - Google Patents

Abstract

To provide a triangular wave output circuit capable of ensuring output waveform.SOLUTION: A triangular wave output circuit 100 includes a first output circuit 11 and a second output circuit 12. The first output circuit 11 outputs a reference voltage V1. The second output circuit 12 outputs a fluctuation voltage V2 in which the voltage value repeats alternating rise and fall following reference voltage V1. The second output circuit 12 outputs the fluctuation voltage V2 as triangle wave V2 by adjusting the reference voltage V1 in the first output circuit 11.SELECTED DRAWING: Figure 1

Description

The present disclosure generally relates to a triangular wave output circuit, a PWM signal output circuit, a drive circuit, and a mechanical load generator. More specifically, the present disclosure relates to a triangular wave output circuit that outputs a triangular wave, a PWM signal output circuit, a drive circuit, and a mechanical load generator.

Patent Document 1 discloses a triangular wave generation circuit that generates a triangular wave having a slope between two different potentials by inputting a charge/discharge switching signal to the charge/discharge circuit to switch charging/discharging of a capacitive load. .. In this triangle wave generation circuit, two comparison circuits compare the triangle wave with the high potential and the low potential, respectively. The output signal of the SR latch that latches the outputs of the two comparison circuits is used as the charge/discharge switching signal.

JP, 2009-246595, A

An object of the present disclosure is to provide a triangular wave output circuit, a PWM signal output circuit, a drive circuit, and a mechanical load generator whose output waveform does not easily dull.

A triangular wave output circuit according to an aspect of the present disclosure includes a first output circuit and a second output circuit. The first output circuit outputs a reference voltage. The second output circuit follows the reference voltage and outputs a fluctuating voltage whose voltage value alternately repeats rising and falling. The second output circuit outputs the fluctuating voltage as a triangular wave by adjusting the reference voltage by the first output circuit.

A PWM signal output circuit according to an aspect of the present disclosure includes the above triangular wave output circuit and a comparison circuit. The comparison circuit compares the triangular wave output from the triangular wave output circuit with a threshold voltage, and outputs a PWM signal according to the comparison result.

A drive circuit according to one aspect of the present disclosure includes the PWM signal output circuit described above and a switching element. The switching element is electrically connected between the load power source and the load and is driven by the PWM signal output from the PWM signal output circuit.

A mechanical load generation device according to an aspect of the present disclosure includes the drive circuit described above, a magnetorheological fluid, and a magnetic field generation unit serving as the load. The magnetic field generation unit is driven by the drive circuit to apply a magnetic field to the magnetorheological fluid to change the viscosity of the magnetorheological fluid.

The present disclosure has an advantage that the output waveform is less likely to be dull.

FIG. 1 is an explanatory diagram showing a schematic configuration of a triangular wave output circuit according to an embodiment of the present disclosure. FIG. 2 is an explanatory diagram showing the operation of the above triangular wave output circuit. FIG. 3 is an explanatory diagram showing a schematic configuration of a PWM signal output circuit and a drive circuit using the above triangular wave output circuit. FIG. 4 is an explanatory diagram showing the operation of the above PWM signal output circuit. FIG. 5A is a plan view showing a schematic configuration of a mechanical load generation device according to an embodiment of the present disclosure. FIG. 5B is a sectional view taken along line X1-X1 of FIG. 5A showing the mechanical load generator of the above. FIG. 6A is an explanatory diagram illustrating an operation of the triangular wave output circuit according to the modified example of the embodiment of the present disclosure. FIG. 6B is an explanatory diagram showing the operation of the drive circuit using the above triangular wave output circuit.

(1) Outline The triangular wave output circuit 100 of the present embodiment is a circuit that generates and outputs a triangular wave V2, as shown in FIG. The triangular wave V2 output by the triangular wave output circuit 100 is used for the PWM (Pulse Width Modulation) signal output circuit 200 to output the PWM signal S1 (see FIG. 3). In this embodiment, the triangular wave V2 is a sawtooth wave as shown in FIG. In other words, in the present embodiment, the triangular wave V2 has a larger slope when the signal value (voltage value) is lower than the slope when the signal value is rising.

As shown in FIG. 1, the triangular wave output circuit 100 includes a first output circuit 11 and a second output circuit 12. The first output circuit 11 outputs the reference voltage V1. The second output circuit 12 follows the reference voltage V1 and outputs the fluctuating voltage V2 in which the voltage value alternately repeats rising and falling. That is, as shown in FIG. 2, the fluctuating voltage V2 increases so as to reach the reference voltage V1 when it is lower than the reference voltage V1, and decreases so as to reach the reference voltage V1 when it is higher than the reference voltage V1.

Then, the second output circuit 12 outputs the variable voltage V2 as the triangular wave V2 by adjusting the reference voltage V1 by the first output circuit 11. That is, in the present embodiment, the first output circuit 11 can output the first reference voltage V11 and the second reference voltage V12 (>the first reference voltage V11) as the reference voltage V1. Then, the first output circuit 11 outputs the second reference voltage V12 as the reference voltage V1 when the variation voltage V2 reaches the first reference voltage V11 when the reference voltage V1 is the first reference voltage V11. Further, the first output circuit 11 outputs the first reference voltage V11 as the reference voltage V1 when the variable voltage V2 reaches the second reference voltage V12 when the reference voltage V1 is the second reference voltage V12. In this way, the first output circuit 11 operates so as to alternately output the first reference voltage V11 and the second reference voltage V12, and the reference voltage V1 is adjusted, whereby the second output circuit 12 outputs. The fluctuating voltage V2 is a triangular wave V2.

As described above, in the present embodiment, the triangular wave V2 is indirectly changed by adjusting the reference voltage V1 instead of directly changing the triangular wave (variable voltage) V2. Therefore, in the present embodiment, compared to the case where the triangular wave V2 is directly changed, the influence on the triangular wave V2 is small, and as a result, the output waveform of the triangular wave output circuit 100 (that is, the waveform of the triangular wave V2) is less likely to become dull. There are advantages.

(2) Details Hereinafter, the triangular wave output circuit 100 of the present embodiment, a PWM signal output circuit 200 using the triangular wave output circuit 100, a drive circuit 300 using the PWM signal output circuit 200, and a mechanical load using the drive circuit 300. The generator 400 will be described in detail. In the following description, a “terminal” such as an “output terminal” does not have to be a component (terminal) for connecting an electric wire, and is, for example, a lead of an electronic component or a part of a conductor included in a circuit board. It may be.

(2.1) Triangular Wave Output Circuit First, the triangular wave output circuit 100 of this embodiment will be described in detail with reference to FIG. The triangular wave output circuit 100 includes a first output circuit 11, a second output circuit 12, a constant current source 13, a capacitor C1, and resistors R1 to R4. The constant current source 13 is composed of, for example, a Wilson type current mirror circuit, and outputs a constant current I1 using the power source P1 as an operating power source. The power source P1 is, for example, a series regulator and outputs a DC voltage.

The first output circuit 11 is a circuit that outputs a voltage (first output voltage V10) based on the reference voltage V1. In this embodiment, the first output circuit 11 has an open collector type first comparator 21 that outputs a voltage based on the reference voltage V1. The power supply P1 is electrically connected to the inverting input terminal of the first comparator 21 via the constant current source 13. The inverting input terminal of the first comparator 21 is electrically connected to the reference potential point (ground) via the capacitor C1. Therefore, the voltage across the capacitor C1 (charging voltage) charged by the constant current I1 supplied from the constant current source 13 is input to the inverting input terminal of the first comparator 21. In this embodiment, the potential at the reference potential point is 0 [V].

Further, the inverting input terminal of the first comparator 21 is electrically connected to the output terminal of the second comparator 22 via the resistor R4. That is, the output voltage (second output voltage V20) of the second comparator 22 is input to the inverting input terminal of the first comparator 21 via the resistor R4. In other words, the fluctuating voltage V2 is a voltage based on the output voltage of the second comparator 22 via the resistor R4, and is the voltage across the capacitor C1 charged by the current I1 from the constant current source 13 (charging voltage ). The resistor R4 is a resistor for limiting the output current of the second comparator 22 within the allowable range of the second comparator 22 when discharging the electric charge charged in the capacitor C1.

The non-inverting input terminal of the first comparator 21 is electrically connected to the connection point of the resistors R1 and R2. Here, the series circuit of the resistor R1 and the resistor R2 is electrically connected between the power source P1 and the reference potential point. That is, the voltage obtained by dividing the output voltage of the power source P1 by the voltage dividing circuit including the resistors R1 and R2 is input to the non-inverting input terminal of the first comparator 21. The non-inverting input terminal of the first comparator 21 is electrically connected to the output terminal of the first comparator 21 via the resistor R3. That is, the output voltage (first output voltage V10) of the first comparator 21 is input to the non-inverting input terminal of the first comparator 21 via the resistor R3. In other words, the reference voltage V1 is a voltage based on the output voltage of the first comparator 21 via the resistor R3. The reference voltage V1 is a voltage obtained by dividing the output voltage of the power source P1 by the voltage dividing circuit including the resistors R1 and R2, or a voltage obtained by dividing the output voltage by the voltage dividing circuit including the resistors R1, R2 and R3.

The second output circuit 12 is a circuit that outputs a voltage (second output voltage V20) based on the fluctuation voltage V2. In the present embodiment, the second output circuit 12 has an open collector type second comparator 22 that outputs a voltage based on the fluctuating voltage V2. The inverting input terminal of the second comparator 22 is electrically connected to the inverting input terminal of the first comparator 21. That is, the fluctuating voltage V2 is input to the inverting input terminals of the first comparator 21 and the second comparator 22. The non-inverting input terminal of the second comparator 22 is electrically connected to the non-inverting input terminal of the first comparator 21. That is, the reference voltage V1 is input to the non-inverting input terminals of the first comparator 21 and the second comparator 22.

The first comparator 21 compares the reference voltage V1 input to the non-inverting input terminal with the fluctuating voltage V2 input to the inverting input terminal. Then, in the first comparator 21, the output transistor of the first comparator 21 is turned on while the reference voltage V1 is lower than the fluctuation voltage V2. Therefore, while the reference voltage V1 is lower than the fluctuation voltage V2, the output voltage of the first comparator 21 (first output voltage V10) is substantially equal to the potential of the reference potential point (here, 0 [V]). Will be equal. Further, while the reference voltage V1 is lower than the fluctuation voltage V2, current flows from the power source P1 to the resistors R1, R2 and R3. Then, while the reference voltage V1 is lower than the fluctuation voltage V2, the first output circuit 11 outputs the first reference voltage V11 (see FIG. 2) as the reference voltage V1. The first reference voltage V11 is the minimum voltage of the reference voltage V1. The first reference voltage V11 is represented by the following mathematical expression (1). In Expression (1) below, “V11” represents the voltage value of the first reference voltage V11. In the following mathematical expression (1) (the same applies to mathematical expression (2) described later), “V0” represents the voltage value of the output voltage of the power source P1, and “R1”, “R2”, and “R3”. "Represents the resistance values of the resistors R1, R2 and R3, respectively.

Further, in the first comparator 21, the output transistor included in the first comparator 21 is turned off while the reference voltage V1 is higher than the fluctuation voltage V2. Further, while the reference voltage V1 exceeds the fluctuation voltage V2, no current flows through the resistor R3. Therefore, while the reference voltage V1 is higher than the fluctuation voltage V2, the output voltage of the first comparator 21 (first output voltage V10) changes the output voltage of the power supply P1 by the voltage dividing circuit including the resistors R1 and R2. It becomes the divided voltage. Then, while the reference voltage V1 is higher than the fluctuation voltage V2, the first output circuit 11 outputs the second reference voltage V12 (see FIG. 2) as the reference voltage V1. The second reference voltage V12 is the maximum voltage of the reference voltage V1. The second reference voltage V12 is represented by the following mathematical expression (2). In Expression (2) below, “V12” represents the voltage value of the second reference voltage V12.

Similar to the first comparator 21, the second comparator 22 compares the reference voltage V1 input to the non-inverting input terminal with the fluctuating voltage V2 input to the inverting input terminal. On the other hand, unlike the first comparator 21, the second comparator 22 outputs the fluctuating voltage V2. Further, since the fluctuating voltage V2 which is the output voltage of the second comparator 22 is the voltage across the capacitor C1 which is charged by the current from the constant current source 13, the reference voltage V1 which is the output voltage of the first comparator 21 is Change later than change. That is, the fluctuating voltage V2 follows the reference voltage V1, and the voltage value alternately repeats increase and decrease.

The fluctuating voltage V2 output from the second comparator 22 increases with time while the fluctuating voltage V2 is lower than the reference voltage V1 (here, the second reference voltage V12) (see FIG. 2). In this case, the fluctuating voltage V2 is represented by the following mathematical expression (3). In the following formula (3) (the same applies to formula (4) described later), “V2” represents the voltage value of the variable voltage V2, “C1” represents the capacitance value of the capacitor C1, and "T" represents time. The “time” mentioned here is a time starting from the time when the fluctuating voltage V2 is inverted (that is, the time when the fluctuating voltage V2 changes from rising to falling or from falling to rising). Further, in the following mathematical expression (3), “I1” represents the current value of the current I1 flowing from the constant current source 13.

The fluctuating voltage V2 output from the second comparator 22 decreases with time while the fluctuating voltage V2 is higher than the reference voltage V1 (here, the first reference voltage V11) (see FIG. 2). In this case, the fluctuating voltage V2 is represented by the following mathematical expression (4). In the following mathematical expression (4), “V22” represents the voltage value of the maximum voltage of the fluctuation voltage V2 (the second fluctuation voltage V22 described later), and “R4” represents the resistance value of the resistor R4. There is. Note that the influence of the constant current source 13 is neglected in Expression (4).

In the triangular wave output circuit 100 configured as described above, the second output circuit 12 (second comparator 22) adjusts the reference voltage V1 by the first output circuit 11 (first comparator 21), and (Variable voltage) V2 is output. The operation of the triangular wave output circuit 100 will be described in detail later in “(3.1) Operation of triangular wave output circuit”.

(2.2) PWM signal output circuit and drive circuit Next, the PWM signal output circuit 200 and the drive circuit 300 of this embodiment will be described in detail with reference to FIG. The PWM signal output circuit 200 includes a triangular wave output circuit 100 and a comparison circuit 3. The drive circuit 300 includes the PWM signal output circuit 200 and the switching element 4.

The comparison circuit 3 is an open collector type comparator. The triangular wave V2 output from the triangular wave output circuit 100 is input to the non-inverting input terminal of the comparison circuit 3. An input signal (voltage signal) Vin output from the control circuit CC1 is input to the inverting input terminal of the comparison circuit 3. The control circuit CC1 will be described later in “(2.3) Mechanical load generator”. Further, in the present embodiment, the signal output from the control circuit CC1 is the input signal Vin input to the comparison circuit 3, but the signal output from the control circuit CC1 is attenuated by an attenuator. The input signal Vin input to the comparison circuit 3 may be used as the input signal Vin.

The comparison circuit 3 compares the triangular wave V2 input to the non-inverting input terminal with the input signal Vin input to the inverting input terminal. Then, as shown in FIG. 4, the comparator circuit 3 is a binary signal (PWM) which is at a high level while the triangular wave V2 is higher than the input signal Vin and is at a low level while the triangular wave V2 is lower than the input signal Vin. Signal) S1 is output. That is, the comparison circuit 3 compares the triangular wave V2 output from the triangular wave output circuit 100 with the threshold voltage (input signal Vin), and outputs the PWM signal S1 according to the comparison result.

The switching element 4 is, for example, a semiconductor switch. In the present embodiment, the switching element 4 is a P-channel enhancement type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The gate of the switching element 4 is electrically connected to the output terminal of the comparison circuit 3 via the resistor R5. The gate of the switching element 4 is electrically connected to the load power source P2 via the resistor R6. The load power source P2 is a DC power source and outputs a DC voltage. In the present embodiment, the load power source P2 is different from the power source P1, but may be the same. The source of the switching element 4 is electrically connected to the load power source P2. The drain of the switching element 4 is electrically connected to the reference potential point (ground) via the load L1. In the present embodiment, the load L1 includes a coil 61 of the magnetic field generation unit 6 described below and a diode. The diode is a return diode for returning a surge current that may occur in the coil 61 when the switching element 4 is off, and is connected in parallel to the coil 61.

When the PWM signal S1 is at high level, the switching element 4 turns off because the gate-source voltage becomes about 0 [V]. On the other hand, when the PWM signal S1 is at a low level, the switching element 4 turns on because the gate-source voltage becomes sufficiently large. That is, the switching element 4 is electrically connected between the load power source P2 and the load L1 and is driven by the PWM signal S1 output from the PWM signal output circuit 200. Therefore, the current I2 flows through the load L1 when the switching element 4 is turned on/off. The magnitude of the current I2 depends on the duty ratio of the PWM signal S1. That is, the current I2 increases as the duty ratio of the PWM signal S1 decreases, and decreases as the duty ratio of the PWM signal S1 increases.

(2.3) Mechanical Load Generating Device Next, the mechanical load generating device 400 of the present embodiment will be described in detail with reference to FIGS. 5A and 5B. The drawings referred to below are all schematic views, and the ratios of the sizes and thicknesses of the respective constituent elements in the drawings do not always reflect the actual dimensional ratios. In the description below, the direction along the rotary shaft 70 of the operating body 7 is referred to as the vertical direction, and particularly the direction in which the operating body 7 projects from the cover 9 (the upper side in FIG. 5B) is described as “upper”. However, these directions are not intended to limit the use direction of the mechanical load generator 400.

The mechanical load generator 400 includes an operating body 7, a rotor 51, a magnetorheological fluid 5, a magnetic field generator 6, a coil bobbin 8, a cover 9, a body 92, and a case 93. The “magnetorheological fluid 5” in the present disclosure is a functional fluid having a property that viscosity reversibly changes according to the strength of an applied magnetic field, more specifically, MRF (Magnetorheological Fluid), The higher the applied magnetic field, the higher the viscosity.

In the present embodiment, the mechanical load generation device 400 is an input device that receives a user's operation on the operating body 7. Hereinafter, the “mechanical load generation device 400” will be referred to as the “input device 400” unless otherwise specified. The “operation” as referred to in the present disclosure includes all that a user applies an external force to the operating body 7, and examples of the operation of the operating body 7 include a rotating operation, a sliding operation, a pushing operation, and a pulling operation. In the present embodiment, as an example, the operating body 7 is configured to be rotatable, and the user rotates the operating body 7. That is, the input device 400 is a rotary operation type device that receives a rotary operation of the operating body 7 by the user. More specifically, the input device 400 is a rotary encoder.

The operating body 7 is formed in a cylindrical shape. The operating body 7 is supported by a cover 9 and a body 92 so as to be rotatable around a rotating shaft 70 passing through the central axis thereof. The operating body 7 has a coupling portion 71 coupled to the rotor 51 and a support portion 72 supported by a bearing portion 94 described later. The connecting portion 71 is provided in the central portion of the operating body 7 in the vertical direction, and the supporting portion 72 is provided at the lower end portion of the operating body 7.

The rotor 51 is formed in a disk shape centering on the rotation shaft 70 of the operating body 7. The rotor 51 rotates around the rotary shaft 70 of the operating body 7 as the operating body 7 is operated. In the present embodiment, the rotor 51 is directly connected to the operating body 7 at the connecting portion 71. Therefore, when the operating body 7 rotates about the rotating shaft 70, the rotor 51 rotates about the rotating shaft 70 together with the operating body 7. The rotor 51 is formed of, for example, a magnetic material (ferromagnetic material).

The coil bobbin 8 is formed in a cylindrical shape around the rotation shaft 70 of the operating body 7. That is, the coil bobbin 8 is hollow, and the cover 9 and the body 92 are housed in the coil bobbin 8. The coil 61 of the magnetic field generator 6 is attached to the coil bobbin 8. The coil bobbin 8 is made of synthetic resin, for example.

The cover 9 is formed in a disk shape centering on the rotation shaft 70 of the operating body 7. A circular through hole 91 is formed in the center of the cover 9 in a plan view. The operating body 7 penetrates the cover 9 through the through hole 91 in the vertical direction. The cover 9 is formed of, for example, a magnetic material (ferromagnetic material).

The body 92 is formed in a cylindrical shape centered on the rotation shaft 70 of the operating body 7. At the center of the upper surface of the body 92, a bearing portion 94, which is a concave portion that opens in a circular shape, is formed. The support portion 72 of the operating body 7 is supported by the body 92 while being inserted into the bearing portion 94. The body 92 is formed of, for example, a magnetic material (ferromagnetic material).

The case 93 is formed in a bottomed cylindrical shape with an open upper surface. Here, at least a part of the coil bobbin 8 is housed in the case 93 together with the body 92 so that the coil 61 fits in the case 93.

Here, the cover 9 and the body 92 are fixed to the coil bobbin 8 so as to face each other with a predetermined gap therebetween in the vertical direction. Then, inside the coil bobbin 8, a housing space 50 is formed between the lower surface of the cover 9 and the upper surface of the body 92.

The rotor 51 is housed in the housing space 50. The rotor 51 has a gap with respect to the inner surface of the accommodation space 50 (the lower surface of the cover 9, the upper surface of the body 92, and the inner peripheral surface of the coil bobbin 8) so that the rotor 51 does not contact the cover 9, the body 92, and the coil bobbin 8 even during rotation. It is accommodated in the accommodation space 50 in a state of being empty.

Further, the magnetorheological fluid 5 is interposed between the surface of the rotor 51 and the inner surface of the accommodation space 50. In this embodiment, the magnetorheological fluid 5 is filled in the accommodation space 50. That is, the rotor 51 is arranged in the magnetorheological fluid 5. Therefore, the gap between the surface of the rotor 51 and the inner surface of the accommodation space 50 is filled with the magnetorheological fluid 5. A packing 81 is mounted between the upper surface of the coil bobbin 8 and the lower surface of the cover 9, and a packing 82 is mounted between the lower surface of the coil bobbin 8 and the inner bottom surface of the case 93. The packing 81 and the packing 82 ensure the airtightness (watertightness) of the accommodation space 50.

Here, the magnetorheological fluid 5 is a functional fluid whose viscosity increases as the applied magnetic field becomes stronger. That is, the viscosity of the magnetorheological fluid 5 is not constant, but changes according to the magnetic field applied to the magnetorheological fluid 5. Since the rotor 51 rotates while being in contact with the magnetic viscous fluid 5, a resistance force (mechanical load) corresponding to the viscosity of the magnetic viscous fluid 5 is generated with respect to the rotation of the rotor 51. Therefore, if the viscosity of the magnetorheological fluid 5 changes, the magnitude of the resistance to the rotation of the rotor 51 changes, and the magnitude of the resistance to the operation (rotation) of the operating body 7 connected to the rotor 51 also changes. In the present embodiment, it is assumed that the viscosity of the magnetorheological fluid 5 changes between the highest viscosity and the lowest viscosity according to the applied magnetic field.

That is, in the state where the magnetic field is not applied to the magnetorheological fluid 5, the viscosity of the magnetorheological fluid 5 is at the minimum viscosity, and the resistance force generated by the magnetorheological fluid 5 against the rotation of the rotor 51 becomes the minimum value. .. At this time, the reaction force (resistive force) applied from the operation body 7 to the user who operates the operation body 7 becomes the minimum value, and the operation feeling of the operation body 7 becomes relatively light. On the other hand, in the state where the magnetic field is applied to the magnetorheological fluid 5, the viscosity of the magnetorheological fluid 5 is at the maximum viscosity, and the resistance force generated by the magnetorheological fluid 5 against the rotation of the rotor 51 becomes the maximum value. .. At this time, the reaction force (resistive force) applied from the operating body 7 to the user who operates the operating body 7 becomes the maximum value, and the operation feeling of the operating body 7 becomes heavy. Therefore, the input device 400 presents a sense of force to the user by changing the magnitude of the reaction force (resistive force) applied from the operating body 7 to the user operating the operating body 7.

Here, the magnetic field generation unit 6 has a coil 61 that causes a magnetic field to act on the magnetorheological fluid 5. The coil 61 is driven by the drive circuit 300 (see FIG. 3). That is, the drive circuit 300 is a circuit that applies a magnetic field from the magnetic field generation unit 6 to the magnetorheological fluid 5 by causing an exciting current (current I2) to flow through the coil 61. In other words, the magnetic field generation unit 6 is the load L1 and is driven by the drive circuit 300 to apply a magnetic field to the magnetic viscous fluid 5 to change the viscosity of the magnetic viscous fluid 5. In the present embodiment, the drive circuit 300 is controlled by the control circuit CC1 (see FIG. 3).

The control circuit CC1 is a circuit that controls the drive circuit 300 based on an operation signal output from the input device 400 according to the displacement amount of the operating body 7 (displacement due to the rotational movement of the operating body 7). The control circuit CC1 mainly includes, for example, a computer including a processor and a memory. With this configuration, the function as the control circuit CC1 is realized by the processor executing the program recorded in the memory. The program may be pre-recorded in the memory of the computer, may be provided through an electric communication line, or may be recorded in a non-transitory recording medium such as a computer-readable memory card, an optical disk or a hard disk drive. May be provided.

The control circuit CC1 controls the drive circuit 300 based on the input operation signal, and changes the strength of the magnetic field applied from the magnetic field generation unit 6 to the magnetorheological fluid 5. As a result, the resistance force acting on the operating body 7 changes according to the amount of displacement of the operating body 7. In the present embodiment, as an example, the control circuit CC1 outputs the input signal Vin based on the input operation signal to the comparison circuit 3 of the PWM signal output circuit 200. As a result, the control circuit CC1 changes the strength of the magnetic field applied from the magnetic field generation unit 6 to the magnetorheological fluid 5 by performing PWM control of the drive circuit 300. Here, the control circuit CC1 stores, for example, the correlation between the operation signal and the strength of the magnetic field applied from the magnetic field generation unit 6 to the magnetorheological fluid 5 in advance. The drive circuit 300 is controlled based on this.

(3) Operation The operation of the triangular wave output circuit 100 of this embodiment will be described below with reference to FIGS. 1 and 2. First, when the power source of the power source P1 is turned on, a voltage obtained by dividing the power source voltage of the power source P1 by the series circuit of the resistors R1 and R2 is input to the non-inverting input terminal of the first comparator 21. The voltage (charging voltage) across the capacitor C1 is input to the inverting input terminal of the first comparator 21. Here, since the capacitor C1 is not charged when the power source P1 is turned on, the charging voltage is almost zero. Therefore, since the input voltage of the non-inverting input terminal exceeds the input voltage of the inverting input terminal, the output voltage of the first comparator 21 (first output voltage V10) is the output voltage of the power supply P1 to the resistors R1 and R2. The voltage is divided by the voltage divider circuit that includes it. Then, the reference voltage V1 becomes the second reference voltage V12.

On the other hand, the non-inverting input terminal of the second comparator 22 receives a voltage (here, the second reference voltage V12) obtained by dividing the power supply voltage of the power supply P1 by the series circuit of the resistors R1 and R2. The voltage across the capacitor C1 (charging voltage) is input to the inverting input terminal of the second comparator 22, but like the above, the charging voltage is almost zero when the power source P1 is turned on. Therefore, since the input voltage (reference voltage V1) of the non-inverting input terminal exceeds the input voltage (fluctuation voltage V2) of the inverting input terminal, the capacitor C1 starts to be charged by the current I1 from the constant current source 13. For this reason, the fluctuating voltage V2 increases with time until it reaches the reference voltage V1 (here, the second reference voltage V12).

At time t1, when the fluctuating voltage V2 reaches the reference voltage V1 (here, the second reference voltage V12), in the first comparator 21, the input voltage of the non-inverting input terminal (reference voltage V1) is the input voltage of the inverting input terminal. It falls below (variable voltage V2). Therefore, the output voltage (first output voltage V10) of the first comparator 21 becomes substantially equal to the potential of the reference potential point (here, 0 [V]). Then, the reference voltage V1 is inverted from the second reference voltage V12 to the first reference voltage V11. Then, in the second comparator 22, the input voltage (reference voltage V1) of the non-inverting input terminal becomes lower than the input voltage (variable voltage V2) of the inverting input terminal, so that the charge of the capacitor C1 starts to be discharged through the resistor R4. .. Therefore, the fluctuation voltage V2 overshoots to the second fluctuation voltage V22 (>the second reference voltage V12) due to the delay caused by the capacitance component of the capacitor C1, and then the reference voltage V1 (here, the first reference voltage V11). Descends over time until is reached.

After that, at time t2 (>time t1), when the fluctuating voltage V2 reaches the reference voltage V1 (here, the first reference voltage V11), in the first comparator 21, the input voltage of the non-inverting input terminal (reference voltage V1). Exceeds the input voltage (fluctuation voltage V2) at the inverting input terminal. Therefore, the output voltage (first output voltage V10) of the first comparator 21 is a voltage obtained by dividing the output voltage of the power source P1 by the voltage dividing circuit including the resistors R1 and R2. Then, the reference voltage V1 is inverted from the first reference voltage V11 to the second reference voltage V12. Then, in the second comparator 22, the input voltage (reference voltage V1) of the non-inverting input terminal exceeds the input voltage (variable voltage V2) of the inverting input terminal, so that the capacitor C1 is charged by the current I1 from the constant current source 13. start. Therefore, the fluctuation voltage V2 undershoots to the first fluctuation voltage V21 (>the first reference voltage V11) due to the delay caused by the capacitance component of the capacitor C1, and then the reference voltage V1 (here, the second reference voltage V12). Rises over time until reaches.

After that, at time t3 (>time t2), when the fluctuation voltage V2 reaches the reference voltage V1 (here, the second reference voltage V12), the output voltage of the first comparator 21 (first output voltage V10) is substantially equal to the potential at the reference potential point (here, 0 [V]). Then, the reference voltage V1 is inverted from the second reference voltage V12 to the first reference voltage V11. Then, like the time t1, the fluctuating voltage V2 overshoots to the second fluctuating voltage V22 (>the second reference voltage V12), and then the time until it reaches the reference voltage V1 (here, the first reference voltage V11) It descends with the passage of time. Further, at time t4 (>time t3), when the variable voltage V2 reaches the reference voltage V1 (here, the first reference voltage V11), the output voltage of the first comparator 21 (first output voltage V10) is a voltage obtained by dividing the output voltage of the power source P1 by the voltage dividing circuit including the resistors R1 and R2. Then, the reference voltage V1 is inverted from the first reference voltage V11 to the second reference voltage V12. Then, the fluctuation voltage V2 undershoots to the first fluctuation voltage V21 (>the first reference voltage V11), and then reaches the reference voltage V1 (here, the second reference voltage V12) until the fluctuation voltage V2 undershoots the time. Increases with time.

Hereinafter, by repeating the above operation, the triangular wave output circuit 100 outputs the variable voltage V2 as the triangular wave V2. Here, the amplitude, the minimum voltage, and the maximum voltage of the triangular wave V2 can be basically determined by the power supply voltage of the power supply P1 and the resistance values of the resistors R1 to R3. The oscillation frequency of the triangular wave V2 basically depends on the power supply voltage of the power supply P1, the capacitance value of the capacitor C1, the resistance value of the resistor R4, and the current value of the current I1 supplied from the constant current source 13. It is possible to decide.

As described above, in the present embodiment, the triangular wave V2 is indirectly changed by adjusting the reference voltage V1 instead of directly changing the triangular wave (variable voltage) V2. Specifically, in the present embodiment, the output voltage of the first comparator 21 (first output voltage V10), the input voltage of the second comparator 22 (reference voltage V1), and the output voltage of the second comparator 22 (second output). Since the voltage changes in the order of V20), the capacitor C1 is indirectly charged and discharged. Therefore, in the present embodiment, compared with the case where the triangular wave V2 is directly changed, the influence on the triangular wave V2 is small, and as a result, the output waveform of the triangular wave output circuit 100 (that is, the waveform of the triangular wave V2) is less likely to become dull. There are advantages.

In addition, the present embodiment can enjoy the following advantages. That is, the triangular wave output circuit 100 of this embodiment does not have a delay circuit or a non-linear element such as a diode that affects the output voltage of the first comparator 21 and the second comparator 22. Therefore, in the present embodiment, compared to the delay circuit or the circuit including the diode, there is an advantage that it is less affected by the environment such as temperature change and the linearity of the slope of the triangular wave V2 can be improved.

The stability of the operation of the triangular wave output circuit 100 of this embodiment depends on the characteristics of the first comparator 21 and the second comparator 22. Therefore, the triangular wave output circuit 100 of the present embodiment has an advantage that the operation stability is easily improved as compared with the circuit in which the operation stability depends on the variation in the performance of the circuit elements.

Note that the triangular wave generation circuit may be configured by using an operational amplifier instead of the comparator depending on the required linearity. The operational amplifier has a built-in phase compensation capacitor for use in negative feedback. When the triangular wave generation circuit is configured using an operational amplifier including a phase compensation capacitor, it is difficult to follow an acute change including a high frequency component due to the characteristics of the high cut filter due to the influence of the phase compensation capacitor. Therefore, the triangular wave generation circuit tends to impair the linearity in the vicinity of the change point of the waveform from rising to falling or from falling to rising. For this reason, the triangular wave generation circuit configured using the operational amplifier is inferior in linearity to the triangular wave generation circuit configured using the comparator, but the output waveform becomes slower than that in the case where the conventional latch is used. Can be suppressed.

Further, in the present embodiment, both the first comparator 21 and the second comparator 22 may be general-purpose comparators having a single power source. Therefore, the present embodiment has an advantage that the manufacturing cost of the triangular wave output circuit 100 can be easily reduced.

(4) Modifications The above-described embodiment is only one of the various embodiments of the present disclosure. The above-described embodiment can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved. Hereinafter, modifications of the above-described embodiment will be listed. The modifications described below can be applied in appropriate combination.

In the system including the mechanical load generator 400 according to the present disclosure, for example, the control circuit CC1 or the like includes a computer system. The computer system mainly has a processor and a memory as hardware. The function as the control circuit CC1 in the present disclosure is realized by the processor executing the program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system, may be provided through an electric communication line, or recorded in a non-transitory recording medium such as a memory card, an optical disk, a hard disk drive, etc. that can be read by the computer system. May be provided. The processor of the computer system is composed of one or a plurality of electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). The integrated circuit such as IC or LSI referred to here is called differently depending on the degree of integration, and includes an integrated circuit called system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). Further, an FPGA (Field-Programmable Gate Array) that is programmed after the manufacture of the LSI, or a logic device capable of reconfiguring the connection relation inside the LSI or reconfiguring the circuit section inside the LSI should also be adopted as a processor. You can The plurality of electronic circuits may be integrated in one chip, or may be distributed and provided in the plurality of chips. The plurality of chips may be integrated in one device, or may be distributed and provided in the plurality of devices. The computer system referred to herein includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or a plurality of electronic circuits including a semiconductor integrated circuit or a large scale integrated circuit.

Further, for example, it is not essential that the plurality of functions of the control circuit CC1 are integrated in one housing. That is, the constituent elements of the control circuit CC1 may be distributed and provided in a plurality of housings. Further, for example, at least a part of the functions of the control circuit CC1 may be realized by, for example, a server device and a cloud (cloud computing).

In the above-described embodiment, the minimum voltage of the triangular wave (variable voltage) V2 is almost 0 [V] as shown in FIG. 2, but the present invention is not limited to this. For example, the minimum value (first fluctuating voltage V21) of the triangular wave (fluctuation voltage) V2 may be larger than zero as shown in FIG. 6A. This mode can be realized, for example, by adjusting the resistance values of the resistors R1, R2, R3 so that the first reference voltage V11 becomes larger than that in the above-described embodiment.

In the PWM signal output circuit 200 using the triangular wave output circuit 100 of this aspect, the output voltage of the comparison circuit 3 is maintained at a high level until the input signal Vin exceeds the minimum voltage of the triangular wave V2 (first fluctuating voltage V21). .. In other words, the PWM signal output circuit 200 does not output the PWM signal S1 until the input signal Vin exceeds the minimum voltage of the triangular wave V2. That is, in the PWM signal output circuit 200 using the triangular wave output circuit 100 of this aspect, the mode for generating the PWM signal S1 and the mode for not generating the PWM signal S1 can be switched depending on the magnitude of the input signal Vin.

Moreover, in the drive circuit 300 using the PWM signal output circuit 200 of this aspect, the drive mode is a mode in which the switching element 4 is driven by the PWM signal S1 output from the PWM signal output circuit 200. The standby mode is a mode in which the switching element 4 is not driven because the PWM signal S1 is not output from the PWM signal output circuit 200, but the state in which the load power supply P2 is turned on is maintained.

As shown in FIG. 6B, until the input signal Vin exceeds the minimum voltage (first fluctuation voltage V21) of the triangular wave V2, the switching element 4 is maintained in the off state, so that the current I2 does not flow in the load L1. That is, in this case, the drive circuit 300 is operating in the standby mode. On the other hand, when the input signal Vin exceeds the minimum voltage of the triangular wave V2 (first fluctuation voltage V21), the switching element 4 is turned on/off by the PWM signal S1, so that the current I2 flows through the load L1. That is, in this case, the drive circuit 300 is operating in the drive mode.

As described above, in this aspect, the drive mode and the standby mode can be switched depending on the magnitude of the input signal Vin, and therefore there is an advantage that it is not necessary to separately prepare a signal line for realizing the standby mode.

In the above-described embodiment, the switching element 4 is a P-channel enhancement type MOSFET (that is, FET), but is not limited to this, and may be a transistor such as a bipolar transistor. When the switching element 4 is a FET, the time required from off to on and the time required from on to off are almost the same as when the switching element 4 is a transistor, and therefore the linearity of the response to the input is good. , Has the advantage.

In the above-described embodiment, the magnetic field generation unit 6 has the single coil 61, but the configuration is not limited to this, and may have a configuration having a plurality of coils 61. In this aspect, the plurality of coils 61 may be connected in series or may be connected in parallel.

In the above-described embodiment, the PWM signal S1 output from the PWM signal output circuit 200 is used to control the mechanical load generator 400 that uses the magnetorheological fluid 5, but the purpose is not limited. For example, the PWM signal S1 can be used for light control and color control of a light source included in a lighting fixture. In addition, the PWM signal S1 can be used for controlling a tactile sensation providing device using a VCM (Voice Coil Motor), controlling an actuator for a camera, or the like.

In the above-described embodiment, the triangular wave output circuit 100 may be configured by using a resistor instead of the constant current source 13. In this aspect, the fluctuating voltage V2 is the voltage across the capacitor C1 charged by the current I1 flowing from the power source P1 through the resistor. By using a resistor, the triangular wave output circuit 100 is inferior in linearity to the case where the constant current source 13 is used, but can generate a pseudo sawtooth wave more easily and at low cost. In this case, the change of the triangular wave (fluctuation voltage) V2 is expressed by the following mathematical expression (5) when the resistance value of the resistor is “R10”.

(Summary)
As described above, the triangular wave output circuit (100) according to the first aspect includes the first output circuit (11) and the second output circuit (12). The first output circuit (11) outputs a reference voltage (V1). The second output circuit (12) follows the reference voltage (V1) and outputs a fluctuating voltage (V2) in which the voltage value alternately repeats rising and falling. The second output circuit (12) outputs the fluctuating voltage (V2) as a triangular wave (V2) by adjusting the reference voltage (V1) by the first output circuit (11).

According to this aspect, there is an advantage that the output waveform is less likely to be dull.

In the triangular wave output circuit (100) according to the second aspect, in the first aspect, the first output circuit (11) has a first comparator (21) that outputs a voltage based on the reference voltage (V1). The second output circuit (12) has a second comparator (22) that outputs a voltage based on the fluctuating voltage (V2).

According to this aspect, there is an advantage that a circuit for adjusting the reference voltage (V1) can be easily designed.

In the triangular wave output circuit (100) according to the third aspect, in the second aspect, the fluctuating voltage (V2) is the voltage across the capacitor (C1) charged by the current (I1) from the constant current source (13). Is. The reference voltage (V1) is input to the non-inverting input terminals of the first comparator (21) and the second comparator (22). The fluctuation voltage (V2) is input to the inverting input terminals of the first comparator (21) and the second comparator (22).

According to this aspect, there is an advantage that it is easy to design a circuit that causes the variable voltage (V2) to follow the reference voltage (V1).

In the triangular wave output circuit (100) according to the fourth aspect, in the second aspect, the fluctuating voltage (V2) is the capacitor (C1) charged by the current (I1) flowing from the power source (P1) through the resistor. Is the voltage across. The reference voltage (V1) is input to the non-inverting input terminals of the first comparator (21) and the second comparator (22). The fluctuation voltage (V2) is input to the inverting input terminals of the first comparator (21) and the second comparator (22).

According to this aspect, there is an advantage that it is easy to design a circuit that causes the variable voltage (V2) to follow the reference voltage (V1).

In the triangular wave output circuit (100) according to the fifth aspect, in any one of the first to fourth aspects, the triangular wave (V2) is a sawtooth wave.

According to this aspect, when the PWM signal (S1) is generated using the triangular wave (V2), there is an advantage that the rising timing (or falling timing) of the PWM signal (S1) can be easily made constant for each cycle.

In the triangular wave output circuit (100) according to the sixth aspect, in any one of the first to fifth aspects, the minimum value of the fluctuation voltage (V2) is larger than zero.

According to this aspect, when the PWM signal (S1) is generated by comparing the triangular wave (V2) with the threshold voltage (input signal) (Vin), the PWM signal (S1) is generated according to the magnitude of the input signal (Vin). There is an advantage that it is possible to switch between the mode to be performed and the mode not to be generated.

The PWM signal output circuit (200) according to the seventh aspect includes the triangular wave output circuit (100) according to any one of the first to sixth aspects and a comparison circuit (3). The comparison circuit (3) compares the triangular wave (V2) output from the triangular wave output circuit (100) with the threshold voltage (Vin), and outputs a PWM signal (S1) according to the comparison result.

According to this aspect, since the PWM signal (S1) is generated using the triangular wave (V2) that is hard to dull, there is an advantage that it is easy to output the PWM signal (S1) having a desired characteristic.

The drive circuit (300) according to the eighth aspect includes the PWM signal output circuit (200) of the seventh aspect and the switching element (4). The switching element (4) is electrically connected between the load power source (P2) and the load (L1) and is driven by the PWM signal (S1) output from the PWM signal output circuit (200).

According to this aspect, since the switching element (4) is driven by using the PWM signal (S1) that is easily output with desired characteristics, there is an advantage that the accuracy of driving the switching element (4) is easily improved.

A mechanical load generator (400) according to a ninth aspect is a drive circuit (300) according to the eighth aspect, a magneto-rheological fluid (5), a magnetic field generator (6) as a load (L1), Equipped with. The magnetic field generator (6) changes the viscosity of the magneto-rheological fluid (5) by being driven by the drive circuit (300) to apply a magnetic field to the magnetorheological fluid (5).

According to this aspect, since the viscosity of the magneto-rheological fluid (5) can be changed by using the switching element (4) whose accuracy is easily improved, there is an advantage that a mechanical load having desired characteristics is easily generated. is there.

The configurations according to the second to sixth aspects are not essential for the triangular wave output circuit (100) and can be omitted as appropriate.

11 1st output circuit 12 2nd output circuit 13 constant current source 21 1st comparator 22 2nd comparator 3 comparison circuit 4 switching element 5 magnetorheological fluid 6 magnetic field generation part 100 triangular wave output circuit 200 PWM signal output circuit 300 drive circuit 400 machine Load generator L1 load P1 power supply P2 load power supply S1 PWM signal V1 reference voltage V2 variable voltage (triangular wave)
Vin input signal (threshold voltage)

Claims (9)

A first output circuit for outputting a reference voltage,
A second output circuit that outputs a fluctuating voltage whose voltage value alternates between rising and falling, following the reference voltage;
The second output circuit outputs the fluctuating voltage as a triangular wave by adjusting the reference voltage by the first output circuit.
Triangular wave output circuit. The first output circuit includes a first comparator that outputs a voltage based on the reference voltage,
The second output circuit has a second comparator that outputs a voltage based on the fluctuating voltage,
The triangular wave output circuit according to claim 1. The fluctuating voltage is the voltage across the capacitor charged by the current from the constant current source,
The reference voltage is input to non-inverting input terminals of the first comparator and the second comparator,
The variable voltage is input to the inverting input terminals of the first comparator and the second comparator,
The triangular wave output circuit according to claim 2. The fluctuating voltage is a voltage across a capacitor charged by a current flowing from a power source through a resistor,
The reference voltage is input to non-inverting input terminals of the first comparator and the second comparator,
The variable voltage is input to the inverting input terminals of the first comparator and the second comparator,
The triangular wave output circuit according to claim 2. The triangular wave is a sawtooth wave,
The triangular wave output circuit according to claim 1. The minimum value of the fluctuating voltage is greater than zero,
The triangular wave output circuit according to claim 1. A triangular wave output circuit according to any one of claims 1 to 6,
A comparison circuit that compares the triangular wave output from the triangular wave output circuit with a threshold voltage and outputs a PWM signal according to the comparison result.
PWM signal output circuit. A PWM signal output circuit according to claim 7,
A switching element electrically connected between the load power source and the load and driven by the PWM signal output from the PWM signal output circuit.
Drive circuit. A drive circuit according to claim 8;
Magnetic viscous fluid,
A magnetic field generation unit as the load that changes the viscosity of the magneto-rheological fluid by applying a magnetic field to the magneto-rheological fluid by being driven by the drive circuit,
Mechanical load generator.

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