JP2005253230A - Frequency control circuit and oscillatory type drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a frequency variable range and frequency resolution required for a frequency control circuit 22 of an ultrasonic motor so as to be respectively independent and arbitrary. <P>SOLUTION: This frequency control circuit includes at least two frequency setting circuits for setting frequency and a pulse generating circuit 22b for outputting a pulse wave having frequency set by the frequency setting circuit. In each of the frequency setting circuits, a digital signal having a plurality of bits is inputted. A plurality of upper bits of the digital signal are inputted in a first frequency setting circuit 22a of the frequency setting circuit, and a plurality of lower bits of the digital signal are inputted in a second frequency setting circuit 22c of the frequency setting circuit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a frequency control circuit and a vibration type driving device, and more particularly to a frequency control circuit used in a vibration type driving device called an ultrasonic motor, a vibration wave motor, and the like and the vibration type driving device.

  Conventionally, a vibration type driving device is basically a vibrating body that forms a driving vibration such as a traveling wave by applying an alternating voltage as an alternating signal to a piezoelectric element as an electro-mechanical energy conversion element to an elastic body such as metal. It is configured.

  Then, the contact body is brought into pressure contact with the driving section of the elastic body via the pressurizing means, and the contact body is frictionally driven by the drive vibration formed in the driving section of the elastic body, so that the vibration body and the contact body are relatively moved. I try to let them.

  As such a vibration type driving device, there is an ultrasonic motor using a vibrating body as a stator and a contact body as a rotor.

  The vibrating body includes a structure in which a ring-shaped piezoelectric element plate is bonded to one surface of a ring-shaped or disk-shaped elastic body, and a method of taking out the rotation of the rotor via the output shaft or directly rotating the rotor. There is a method of taking out.

  The piezoelectric element has a positional phase of λ / 4, where λ is the wavelength at the resonance frequency, and a two-phase driving unit is formed, and each phase driving unit has an interval of λ / 2. An electrode is formed. When an alternating voltage is simultaneously applied to a plurality of electrodes in each phase drive unit, polarization processing is performed so that portions extending in the thickness direction and portions shrinking in the thickness direction are alternately formed. Then, standing waves having different phases are formed by these two driving phases, and a traveling wave as driving vibration is formed by synthesizing both standing waves.

  FIG. 6 is a cross-sectional view showing a configuration example of an ultrasonic motor.

  A vibrating body 13 in which a piezoelectric element 13a as an electro-mechanical energy conversion element is bonded to an annular elastic body 13b, a moving body 15 in pressure contact with the elastic body 13b, and a motor center are connected to the moving body 15. By applying a two-phase AC voltage having different phases from a booster circuit 24 of a drive circuit, which will be described later, to the piezoelectric element 13a, the motor shaft 16 and the pressurizing spring 14 holding the vibrating body 13 are elastic. For example, a driving wave as a traveling wave is formed on the body 13b by combining bending vibrations, and the moving body 15 that is in pressure contact with the driving surface of the elastic body 13b on which the driving wave is formed is frictionally driven. It is transmitted to the shaft 16.

  A rotary encoder 17 is provided at the rear end of the motor shaft 16 as means for detecting the rotational speed of the motor.

  FIG. 7 is a graph showing the relationship between the frequency of the AC voltage input to the ultrasonic motor and the rotational speed of the ultrasonic motor.

  As shown in FIG. 7, in general, in an ultrasonic motor, the rotation speed of the ultrasonic motor changes according to the frequency of the AC voltage, and in the frequency region higher than the resonance frequency, the rotation of the ultrasonic motor increases as the frequency increases. The speed gradually decreases, and the motor rotation speed becomes zero when the frequency exceeds a predetermined value.

  Utilizing this property, a method for controlling the frequency of an AC voltage input to the ultrasonic motor is used as a method for controlling the rotation and position of the ultrasonic motor.

  FIG. 8 is a block diagram showing a driving circuit of the ultrasonic motor.

  A rotation speed command signal of the ultrasonic motor is output from the frequency command means 21, a four-phase signal waveform having a frequency corresponding to the command speed is formed in the frequency control circuit 22 and the waveform forming circuit 23, and is output to the booster circuit 24.

  FIG. 9 is a circuit diagram showing the configuration of the booster circuit 24, and FIG. 10 is a chart showing the timing of signals input to the booster circuit 24.

  In the booster circuit 24, the four-phase signals (YA1, YA2, YB1, YB2) are input to the gates of the four FETs 31 at the timing shown in FIG. The A-phase transformer 32a and the B-phase transformer 32b are stepped up to two-phase AC voltages having different phases, and are applied to the piezoelectric elements 13a of the vibration type driving device 25, respectively.

  A pulse train is output as rotational speed information from the speed detection means 26 such as a rotary encoder. When the rotational speed of the motor is high, the frequency of the pulse train is high, and when the rotational speed is low, the frequency is low.

This pulse train is converted into rotational speed information by the speed information converting means 27, and the frequency command means 21 compares the current rotational speed with the target rotational speed, and outputs a rotational speed command signal that becomes a target value. Thereby, the frequency according to the command speed is set by the frequency control circuit 22 and the waveform forming circuit 23, the frequency of the alternating voltage input to the vibration type driving device 25 is set via the booster circuit 24, and a desired frequency is set. It is controlled so as to have a rotational speed.
JP 2000-209882 A JP 2000-184762 A

  However, the above-described ultrasonic motor frequency control circuit has the following problems.

  As shown in FIG. 7, the AC voltage frequency-rotation speed characteristic applied to the ultrasonic motor is a non-linear characteristic, and a high-accuracy frequency control circuit is required for high-accuracy control of the ultrasonic motor.

  Here, characteristics required for the frequency control circuit of the ultrasonic motor will be described.

  In order to control the ultrasonic motor from high speed rotation to stop, it is necessary to set a wide frequency variable range in the frequency control circuit. For example, when the fundamental frequency of the frequency control circuit is 300 kHz, this variable range is 20 kHz. A degree is required.

  At this time, for high-precision rotation control of the ultrasonic motor, high frequency resolution is required particularly in the frequency region in the high-speed rotation region of the ultrasonic motor, and this resolution requires about 4 Hz.

  In a general frequency control circuit, the variable range and the resolution are in a trade-off relationship. When the variable range is widened, the resolution is low, and when the resolution is high, the variable range is narrowed. However, the frequency control circuit of the ultrasonic motor is required to have both a wide frequency variable range and high frequency resolution.

  FIG. 11 is a block diagram showing an example of a conventional ultrasonic motor driving frequency control circuit.

  The frequency control circuit 22 includes a D / A (digital / analog) converter (DAC) as a frequency setting circuit, and a voltage controlled oscillator (VCO) as a pulse generation circuit 22b. A digital signal as frequency setting data from a microcomputer as the command means 21 is input to a D / A converter, and an analog DC voltage output from the D / A converter is input to a voltage controlled oscillator. The frequency of the pulse train output from the controlled oscillator is set and a pulse signal is output.

  FIG. 12 is a graph showing the relationship between the voltage output from the DAC of the frequency control circuit 22 and the frequency output from the VCO.

In this configuration, when the voltage resolution of the D / A converter is expressed as 1LSB, the following equation is established.
Frequency resolution / frequency variable range = (D / A converter 1LSB) / (D / A converter voltage range)
Here, when the frequency control circuit is created by a semiconductor process, the D / A converter voltage range is generally determined by the configuration of the D / A converter itself and the voltage controlled oscillator connected after the D / A converter. In terms of the circuit configuration, the voltage value is obtained by subtracting the Vgs voltage of the MOS transistor from the power supply voltage. Here, the Vgs voltage is a voltage generated between the gate terminal and the source terminal of the MOS transistor, and generally has a value of about 1V.

  Therefore, for example, when a D / A converter is configured with a general microcomputer drive power supply voltage of 3.3 V as a power supply voltage, the frequency resolution and frequency variable range required for driving the ultrasonic motor are simultaneously satisfied. The D / A converter 1LSB is as follows.

D / A converter 1LSB = frequency resolution / frequency variable range × D / A converter voltage range = 4 Hz / 20 kHz × (3.3-1.0) V = 0.5 mV
A D / A converter for realizing this 1LSB at a power supply voltage of 3.3 V is about 16 bits, and a very large scale is required with high accuracy. Therefore, there is a problem that the system becomes expensive and hinders cost reduction.

  In addition, since 1LSB is a very small value of 1 mV or less, there is a problem that it is easily affected by external noise, and high-precision frequency control becomes difficult.

  Furthermore, if the power supply voltage of the D / A converter and the voltage controlled oscillator is provided separately from the power supply voltage for microcomputer driving, etc., if the power supply voltage is very high, 1LSB becomes large, but this makes the system expensive and low There is a problem that the cost is hindered.

  Also, if the shape and material of the ultrasonic motor are different, the applied AC voltage frequency vs. rotational speed characteristics will be different, so the frequency variable range and frequency resolution required for the frequency control circuit will be different for each applied AC voltage frequency. -Depending on the rotational speed characteristics, for high-precision rotation control of the ultrasonic motor, it is necessary to match the frequency variable range and the frequency resolution so as to be optimal for the respective characteristics.

  However, in the conventional ultrasonic motor driving frequency control circuit example of FIG. 11, the frequency resolution and the frequency variable range are determined by the 1LSB of the D / A converter and the voltage range of the D / A converter as described above. In order to control the rotation of various ultrasonic motors with high accuracy in the same frequency control circuit configuration, it is difficult to optimally set the frequency variable range and frequency resolution according to the applied AC voltage frequency-rotation speed characteristics. There is a problem of becoming.

  Therefore, in order to control the rotation of various ultrasonic motors with high accuracy in the same frequency control circuit configuration, it is necessary to provide a frequency control circuit capable of arbitrarily setting the frequency variable range and the frequency resolution. .

  Also, in the frequency control circuit of an ultrasonic motor, if the frequency fluctuates due to an external factor with respect to the set frequency, it directly affects the rotational speed of the ultrasonic motor. A frequency control circuit that is not affected is required.

  The present invention has been made in view of the above-described problems of the prior art, and it is possible to independently and arbitrarily set the frequency variable range and the frequency resolution required for the frequency control circuit of the ultrasonic motor. The problem is to do.

  As a result, not only can the applied AC voltage frequency-rotation speed characteristics be optimized for any ultrasonic motor, but it is also resistant to the effects of external noise with an inexpensive system configuration, and it can be used for variations in power supply voltage, semiconductor processes, and temperature. It is also an object to satisfy characteristics required for ultrasonic motor control that are not affected by external factors such as fluctuations.

  The present invention provides a frequency control circuit comprising a frequency setting circuit, which is a circuit for setting a frequency, and a pulse generation circuit for outputting a pulse wave having a frequency set by the frequency setting circuit, as means for solving the above problems. The frequency setting circuit is provided with at least two, the digital signal having a plurality of bits is input to the frequency setting circuit, and the higher-order multiple bits of the digital signal are the first of the frequency setting circuit. The low-order multiple bits of the digital signal are input to a frequency setting circuit, and are input to a second frequency setting circuit of the frequency setting circuit.

  Further, the present invention is characterized in that a frequency variable range is set by the first frequency setting circuit, and a frequency resolution is set by the second frequency setting circuit.

  Furthermore, the present invention is characterized in that at least one of the first frequency setting circuit and the second frequency setting circuit is a D / A (digital / analog) converter.

  Further, the present invention is characterized in that the pulse generation circuit is a voltage controlled oscillator.

  According to the present invention, the voltage-controlled oscillator includes a triangular wave generation circuit having a capacitor and a charge / discharge current control circuit for controlling the capacitor, and a pulse wave output by controlling the charge / discharge current to the capacitor. It is characterized by controlling the frequency.

  In the present invention, the charging / discharging current of the capacitor is calculated from a value calculated from a predetermined reference voltage value and a resistance value, and a voltage value and a resistance value of a signal output from the D / A converter. It is calculated based on the value.

  Further, according to the present invention, there is provided a vibration type driving device connected to the frequency control circuit, wherein the frequency setting circuit sets the frequency according to a command from frequency command means for commanding the frequency, and according to the frequency The vibration-type driving device is provided in which the vibrating body of the vibration-type driving device is vibrated.

  According to the present invention, since the upper multiple bits of the digital signal are input to the first frequency setting circuit and the lower multiple bits of the digital signal are input to the second frequency setting circuit, the drive control circuit of the ultrasonic motor is provided. The required frequency variable range and frequency resolution can be set independently and arbitrarily.

  Therefore, not only can the applied AC voltage frequency-rotational speed characteristics be optimized for any ultrasonic motor, but it is also resistant to the effects of external noise with an inexpensive system configuration, and variations in power supply voltage, semiconductor processes, and temperature fluctuations It is not affected by external factors such as.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the accompanying drawings, the same members and the same parts as those of the conventional technology are denoted by the same reference numerals. Further, portions other than the frequency control circuit 22 have the same configuration as that of the conventional technique.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described.

  FIG. 1 is a block diagram showing the configuration of the first exemplary embodiment of the present invention.

  As shown in FIG. 1, the frequency control circuit 22 according to the present embodiment receives a digital signal having a plurality of bits, and inputs the upper bits of the digital signal to the first frequency setting circuit 22a. A plurality of bits are input to the second frequency setting circuit 22c and given as a control signal of the pulse generation circuit 22b, the frequency of the pulse train to be output is controlled, and the rotational speed of the ultrasonic motor is controlled.

  FIG. 2 is a block diagram showing a specific example of the circuit configuration of the present embodiment.

  In the present embodiment, the first frequency setting circuit 22a of FIG. 1 is a first D / A converter (DAC1) 22a, and the second frequency setting circuit 22c is a second D / A converter (DAC2). 22c, the pulse generation circuit 22b is composed of a voltage controlled oscillation circuit (VCO) 22b.

First, a digital signal as a frequency setting signal is input from the microcomputer as the frequency command means 21 to the first D / A converter 22a for frequency variable range setting, and output from the first D / A converter 22a. The frequency of the pulse train output from the voltage controlled oscillator 22b is controlled by inputting the analog DC voltage VDAC1 to be input to the voltage controlled oscillator 22b, and the frequency corresponding to the fundamental frequency f ₀ required for the frequency control circuit 22 of the ultrasonic motor. Set the variable range f ₁ .

When this frequency resolution cannot satisfy the frequency resolution required for the frequency control circuit of the ultrasonic motor, a digital signal as a frequency setting signal from the microcomputer is newly set as the second D / D for frequency resolution setting. By inputting the analog DC voltage VDAC2 input to the A converter 22c and output from the second D / A converter 22c to the voltage controlled oscillator 22b, the frequency f ₂ of the pulse train output by the voltage controlled oscillator is obtained. By finely adjusting and setting, the frequency resolution required for the frequency control circuit of the ultrasonic motor is set.

  FIG. 3 is a graph showing the relationship between the voltage input to the first D / A converter 22a of this embodiment and the frequency of the pulse wave output from the voltage controlled oscillator 22b.

This circuitry receives the digital signal as a frequency setting signal to the fundamental frequency f ₀ to the first frequency setting circuit 22a, to control the frequency of the pulse train to be output by the pulse generating circuit 22b, the ultrasonic motor A frequency variable range f ₁ with respect to the fundamental frequency f ₀ required for the frequency control circuit is set.

If this frequency resolution cannot satisfy the frequency resolution required for the frequency control circuit of the ultrasonic motor, a digital signal as a new frequency setting signal is input to the second frequency setting circuit 22c to generate a pulse. by setting the frequency f ₂ of the pulse train to be output by the circuit 22b tweak to, is that setting the frequency resolution required for the frequency control circuit of the ultrasonic motor.

  In the frequency control circuit with this circuit configuration, the variable range and the resolution can be arbitrarily and independently set, so any applied AC voltage frequency-rotational speed characteristics of ultrasonic motors of various shapes and materials can be set. Can also be optimized.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.

  FIG. 4 is a circuit diagram showing a configuration of the pulse generation circuit 22b of the present embodiment. The present embodiment more specifically shows the first embodiment.

Pulse generating circuit 22b shown in FIG. 4 has a triangular wave generating circuit, by controlling the charging and discharging current to capacitor C _0, the circuit that controls the frequency signal to be output by controlling the frequency of the triangular wave It is.

Pulse generating circuit 22b shown in FIG. 4, a capacitor C _0, and the upper limit voltage setting comparator 41a and the lower limit voltage setting comparator 41b of the triangular wave, the upper and lower limit voltage setting resistor 47, the charge and discharge current switch control flip-flop 42, an NMOS transistor 43 that is turned on / off by a signal from the flip-flop 42, a frequency signal output buffer circuit 46 based on the signal from the flip-flop 42, and a plurality of voltage value settings for setting the charge / discharge current Each of the buffers 44 includes a plurality of charge / discharge current value setting resistors 45 corresponding to each buffer 44, and a charge / discharge current setting current mirror circuit 48.

Figure 5 is a graph showing a triangular wave waveform obtained by the triangular wave generating circuit of Figure 4, the relationship between the frequency signal f _VCO and charge and discharge current I _c.

This triangular wave generation circuit is a circuit that controls the frequency of the triangular wave by controlling the charging / discharging current to the capacitor C ₀ and outputs a frequency signal f _VCO synchronized with this frequency.

The upper limit voltage value and the lower limit voltage value of this triangular wave are set, and when this voltage value is exceeded, the voltage setting comparator 41 operates, and this output causes the charge / discharge current switching control flip-flop 42 to operate. the NMOS transistor 43 is turned on / off by a signal based on, switch the charge / discharge of the capacitor _{C o.}

Here, the charging current setting constant current _{I c} of the capacitor _{C o,} the discharge when the current for setting the constant current is set to -2I _c, when the on / off the NMOS transistor charging current _{= I} c of the capacitor _{C o,} The discharge current = −I _c and the frequency signal f _VCO based on the signal from the flip-flop has a duty ratio = 50%.

As shown in FIG. 5, when the power supply voltage is set to VDD, if the upper limit voltage value of the triangular wave is set to 2/3 × VDD and the lower limit voltage value = 1/3 × VDD, the frequency signal f _VCO is set by the following equation. , F _VCO frequency can be controlled by charge / discharge current I _c .
_{f VCO = I c / (2} × C o × (2/3 × VDD-1/3 × VDD))
Here, a plurality of voltage values set buffer 44 for charge and discharge current I _c settings, and a plurality of charge-discharge current value setting resistor 45 corresponding to the respective buffers 44, the charge and discharge current I _c is the This is the sum of the current set by the buffer voltage and the current value setting resistor. For example, basic frequency setting current I ₁ = 1/2 VDD / basic frequency setting resistor R ₁ , variable range setting current I ₂ = VDAC1 / variable range setting resistor R ₂ , resolution setting current I ₃ = VDAC2 / resolution setting resistor R ₃ by setting the charge-discharge current I _c is given by the following formula, and arbitrarily set independently variable range and resolution for the fundamental frequency.
I _c = I ₁ + I ₂ + I ₃ = 1/2 × VDD / R ₁ + VDAC ₁ / R ₂ + VDAC2 / R ₃
Here, since the D / A converter required for this frequency control circuit can set the variable range and the resolution independently, the 1 LSB required for each does not need to be a minute value, and is a small scale of about 8 bits. An inexpensive D / A converter can be sufficiently realized.

Moreover, since it is possible to weight the frequency variation with respect to the voltage value of the D / A converter by setting the resistance value, for example, in the case where high resolution is required to increase the resolution setting resistor R _3, VDAC2 the variation can be realized by reducing the amount of change in resolution setting current I ₃ for wider when the variable range is required to reduce the variable range setting resistor R _2, the variable range set current corresponding to the change in VDAC1 It can be realized by increasing the amount of change I _2.

Moreover, the fundamental frequency also by changing the basic frequency setting resistor R _1, can be set arbitrarily. Therefore, in the frequency control circuit according to this circuit configuration, by adjusting each charge / discharge current setting resistance value for any applied AC voltage frequency-rotation speed characteristic of an ultrasonic motor made of various shapes and materials, The fundamental frequency, variable range, and resolution can be arbitrarily and independently set so as to be optimal.

  In the frequency control circuit of FIG. 4, when the power supply voltage is VDD in the above-described circuit, the upper limit voltage value of the triangular wave = 2/3 × VDD and the lower limit voltage value = 1/3 × VDD are set.

Further, the basic frequency setting current I ₁ = 1/2 × VDD / basic frequency setting resistor R ₁ , variable range setting current I ₂ = (analog DC voltage VDAC1 output from the D / A converter 1) / variable range setting resistor R ₂ , resolution setting current I ₃ = (analog DC voltage VDAC2 output from D / A conversion 2) / resolution setting resistance R ₃ .

Here, when the analog DC voltage output from the D / A converter is set so that the power supply voltage VDD is the reference voltage, the analog DC voltage output from the D / A converter is a voltage dependent on the power supply voltage VDD. Become. At this time, the frequency signal f _VCO is as follows.

_{f VCO = I c / (2} × C 0 × (2/3 × VDD-1/3 × VDD)) = (I 1 + I 2 + I 3) / (2 × C 0 × (2/3 × VDD-1 / 3 × VDD)) = (1/2 × VDD / R ₁ + VDAC1 / R ₂ + VDAC2 / R ₃ ) / (2 × C ₀ × (2/3 × VDD−1 / 3 × VDD))
Here, VDAC1, VDAC2 is because a voltage depending on the power supply voltage _{VDD, f VCO} power supply voltage dependence is eliminated is canceled section on the power supply voltage VDD, is set only by the frequency setting resistor and capacitor C _0, The configuration is very strong against power supply voltage fluctuations.

  Further, when this circuit configuration is manufactured by a semiconductor process, the frequency control circuit has a small amount of fluctuation with respect to semiconductor process variations and temperature fluctuations.

  In the frequency control circuit of an ultrasonic motor, if the frequency fluctuates due to an external factor with respect to the set frequency, it directly affects the rotational speed of the ultrasonic motor and is not affected by the external factor. A frequency control circuit is required. The frequency control circuit described above also satisfies this condition.

  Here, in the frequency control circuit 22 of FIG. 1, the digital signal as the frequency setting signal may be input to the frequency setting circuit in any format.

  Further, in the frequency control circuit 22 of FIG. 1, the frequency setting circuit may be divided into not only the variable range and the resolution described above but also divided to provide the frequency setting circuit.

  Further, this frequency control circuit may be applied to the position control of the ultrasonic motor. In the triangular wave generating circuit, it is not always necessary to use a triangular wave as long as frequency control is possible.

  In the triangular wave generation circuit, the current calculation of each current value for setting the charge / discharge current to the capacitor may be a calculation other than the above addition.

  Moreover, although the frequency characteristic shown in FIG. 3 is a linear characteristic, it may be a non-linear characteristic.

It is a block diagram which shows the structure of the 1st Embodiment of this invention. It is a block diagram which shows the specific example of the circuit structure of the 1st Embodiment of this invention. It is the graph which showed the relationship between the voltage input into the 1st D / A converter of the 1st Embodiment of this invention, and the frequency output from a voltage control oscillator. It is a circuit diagram which shows the structure of the pulse generation circuit 22b of this Embodiment. Triangular wave is obtained by the triangular wave generation circuit in FIG. 4 is a graph showing the relationship between the frequency signal f _VCO and charge and discharge current I _c. It is sectional drawing which shows one structural example of an ultrasonic motor. It is a graph which shows the relationship between the frequency of the alternating voltage input into an ultrasonic motor, and the rotational speed of an ultrasonic motor. It is a block diagram which shows the drive circuit of an ultrasonic motor. 3 is a circuit diagram showing a configuration of a booster circuit 24. FIG. 3 is a chart showing timing of signals input to a booster circuit 24. It is a block diagram which shows an example of the conventional ultrasonic motor drive frequency control circuit 22. FIG. 4 is a graph showing the relationship between the voltage output from the DAC of the frequency control circuit 22 and the frequency output from the VCO.

Explanation of symbols

DESCRIPTION OF SYMBOLS 13 Vibrating body 13a Piezoelectric element 13b Elastic body 14 Pressure spring 15 Moving body 16 Motor shaft 17 Rotary encoder 21 Frequency command means 22 Frequency control circuit 22a First frequency setting circuit (DAC1)
22b Pulse generator (VCO)
22c Second frequency setting circuit (DAC2)
DESCRIPTION OF SYMBOLS 23 Waveform formation circuit 24 Booster circuit 25 Vibration type drive device 26 Speed detection means 27 Speed information conversion means

Claims (7)

In a frequency control circuit comprising a frequency setting circuit that is a circuit for setting a frequency, and a pulse generation circuit that outputs a pulse wave having a frequency set by the frequency setting circuit.
The frequency setting circuit includes at least two, a digital signal having a plurality of bits is input to the frequency setting circuit, and a plurality of upper bits of the digital signal are the first frequency setting of the frequency setting circuit. A frequency control circuit, wherein the low-order multiple bits of the digital signal are input to a second frequency setting circuit of the frequency setting circuit. 2. The frequency control circuit according to claim 1, wherein a frequency variable range is set by the first frequency setting circuit, and a frequency resolution is set by the second frequency setting circuit. 3. The frequency control circuit according to claim 1, wherein at least one of the first frequency setting circuit and the second frequency setting circuit is a D / A (digital / analog) converter. 4. The frequency control circuit according to claim 1, wherein the pulse generation circuit is a voltage controlled oscillator. The voltage controlled oscillator includes a triangular wave generation circuit having a capacitor and a charge / discharge current control circuit for controlling the capacitor, and controls a frequency of a pulse wave to be output by controlling a charge / discharge current to the capacitor. 5. The frequency control circuit according to claim 4, wherein: The charge / discharge current of the capacitor is based on a value calculated from a predetermined reference voltage value and a resistance value and a value calculated from a voltage value and a resistance value of a signal output from the D / A converter. 6. The frequency control circuit according to claim 3, wherein the frequency control circuit is calculated as follows. A vibration type driving device connected to the frequency control circuit according to any one of claims 1 to 6,
The vibration type driving device according to claim 1, wherein the frequency setting circuit sets the frequency according to a command from a frequency command means for commanding a frequency, and vibrates the vibrating body of the vibration type driving device according to the frequency.

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