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DESCRIPTION JPH09206681

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DESCRIPTION JPH09206681
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
drive device for an ultrasonic transducer. 2. Description of the Related Art As an example of a
driving device for an ultrasonic cleaning machine that converts electrical energy into ultrasonic
vibration using an electro-mechanical energy conversion element, page 50, "Ultrasonic
Technology", edited by the University of Tokyo Press, Figure 2.34. The one described in is
known.
[0002]
This drive device is a drive circuit of an ultrasonic cleaning machine (ultrasonic transducer) using
a piezoelectric ceramic (ceramics) as an electro-mechanical energy conversion element, and its
outline is shown in FIG.
[0003]
The drive circuit is composed of a self-oscillation circuit to drive the ultrasonic transducer at a
mechanical resonance frequency.
[0004]
Here, the basic configuration of the oscillation circuit will be described with reference to FIGS. 5
to 10, and the self-oscillation circuit will be described with reference to FIG.
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1
[0005]
In general, the basic configuration of the oscillation circuit is as shown in FIG.
This oscillation circuit comprises an amplifier 41 with a gain (amplification factor) of α and a
feedback circuit 42 with a gain of β, and the output Vo of this oscillation circuit is taken out
from the amplifier 41.
And, it oscillates stably when α × β = 1.
When α × β> 1, the vibration amplitude is limited by the power supply voltage Vs of the
amplifier 41, and does not diverge as shown by the dotted line in the oscillation waveform shown
in FIG. That is, the gain of the amplifier 41 is limited, and it is apparent that α × β = 1.
[0006]
Also, even if the gain is not limited by the power supply voltage Vs, if some sort of gain limiting
circuit is added, α × β = 1 apparently as well. Then, as shown in FIG. 7, when the phase shift
amount of the feedback circuit 42 is made to have frequency characteristics, oscillation occurs at
a frequency fo at which the phase shift amount is 0 degree.
[0007]
On the other hand, an ultrasonic transducer using a piezoelectric ceramic having mechanical
resonance characteristics is shown by an equivalent circuit in which a capacitor Cd is connected
in parallel to a series circuit of an inductor L, a capacitor C and a resistor R as shown in FIG. The
relationship between the absolute value | Z | of the impedance of this equivalent circuit and the
frequency is as shown in FIG.
[0008]
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The absolute value | Z | becomes minimum near the mechanical resonance frequency fr and
becomes maximum near the antiresonance frequency fa slightly higher than this. Further, as
shown in FIG. 10, the phase φ is 0 degrees in the vicinity of the mechanical resonance frequency
fr and in the vicinity of the antiresonance frequency fa. When a piezoelectric ceramic having
such frequency characteristics is used as part of the feedback circuit 42 of FIG. 5 and the
absolute value | Z | becomes small near the mechanical resonance frequency fr, α × β = 1 Is
adopted, oscillation occurs at a frequency at which the phase φ is 0 degrees. Similarly, if the
above-mentioned configuration is adopted such that α × β = 1 when the absolute value | Z |
becomes large in the vicinity of the antiresonance frequency fa, oscillation occurs at a frequency
at which the phase φ is 0 degrees.
[0009]
Next, in the self-oscillation circuit shown in FIG. 11, a transformer 51 and a piezoelectric ceramic
vibrator (ceramics) 52 are connected in series to a part of the feedback circuit. As described
above, since the absolute value of the impedance is minimized near the mechanical resonance
frequency fr of the piezoelectric ceramic vibrator 52, the current flowing through the primary
winding (2T) of the transformer 51 is maximized, and as a result, The voltage induced in the two
secondary windings (12T) of the transformer 51 is maximized. The self-oscillation circuit is
connected to a power supply of AC 100 (V), and a drive voltage is supplied through the line filter
53 and the bridge circuit 54.
[0010]
The feedback amount of the feedback circuit becomes extremely large in the vicinity of the
mechanical resonance frequency fr, and the phase shift amount of the feedback circuit also
becomes 0 degree in the vicinity of the mechanical resonance frequency fr. The output of this
feedback circuit is input as a current to each base of the transistors Q1 and Q2 which is an input
terminal of the amplification circuit 53 using two transistors Q1 and Q2.
[0011]
Then, the product of the feedback amount of the feedback circuit and the gain of the amplifier
circuit 43 is 1, and the phase shift amount is 0 degrees, that is, oscillation occurs in the vicinity
of the mechanical resonance frequency fr. For this reason, even if the mechanical resonance
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frequency fr changes, the transmission frequency automatically approximately matches the
mechanical resonance frequency fr.
[0012]
The self-oscillation circuit can track the mechanical resonance frequency of the ultrasonic
transducer very efficiently. However, it is not possible to drive an ultrasonic transducer that
requires a plurality of voltages with different phases, for example, a plurality of ultrasonic
transducers used in an ultrasonic motor. That is, the ultrasonic motor often requires a two-phase
voltage waiting for a suitable phase difference, and in such a case, it is difficult to use the selfoscillation circuit of the conventional example.
[0013]
Then, an object of this invention is to provide the drive device which can drive the ultrasonic
transducer | vibrator which requires the several drive voltage which waited for the
predetermined | prescribed phase difference.
[0014]
According to a first aspect of the present invention, there is provided a drive apparatus for
driving an ultrasonic transducer by supplying a drive voltage to an ultrasonic transducer having
a plurality of terminals. A first waveform generation circuit for supplying a drive voltage by a
self-oscillation circuit oscillating at the resonance frequency of the ultrasonic transducer to a first
terminal of the first and a drive voltage of the first waveform generation circuit by a phase locked
loop; A predetermined phase difference with respect to a drive voltage of the first waveform
generation circuit based on a PLL circuit generating a plurality of signals having a frequency that
is an integral multiple of the frequency and the plurality of signals from the PLL circuit And a
second waveform generation circuit that generates one or more drive voltages and supplies the
other voltage to the other terminal of the ultrasonic transducer.
[0015]
According to a second aspect of the present invention, in the drive device for supplying a drive
voltage to an ultrasonic transducer having a plurality of terminals to drive the ultrasonic
transducer, the ultrasonic wave is transmitted to one terminal of the ultrasonic transducer. A first
waveform generation circuit that supplies a drive voltage by a self-oscillation circuit that
oscillates at an antiresonance frequency of a vibrator, and a frequency that is an integral multiple
of the frequency of the drive voltage of the first waveform generation circuit by a phase locked
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loop And one or a plurality of drive voltages having a predetermined phase difference with
respect to the drive voltage of the first waveform generation circuit based on the PLL circuit
generating a plurality of signals having the above and the plurality of signals from the PLL circuit
And a second waveform generation circuit that supplies the other waveform to the other terminal
of the ultrasonic transducer.
[0016]
According to the driving device in accordance with the first aspect of the present invention, the
self-oscillation of the first waveform generation circuit generates a driving voltage having a
frequency substantially coincident with the resonance frequency of the ultrasonic transducer,
thereby generating an ultrasonic transducer. A plurality of signals having a frequency that is an
integral multiple of the frequency of the drive voltage of the first waveform generation circuit are
generated by the phase locked loop, and the first waveform generation circuit generates the
plurality of signals. And generating one or more drive voltages having a predetermined phase
difference with respect to the drive voltage of the waveform generation circuit, and supplying
this drive voltage to the other terminal of the ultrasonic transducer.
Thereby, the ultrasonic transducer can be driven by a plurality of drive voltages having the
resonance frequency and waiting for a predetermined phase difference.
[0017]
According to the drive device of the second aspect of the present invention, the ultrasonic
transducer is generated by generating the drive voltage having a frequency substantially
coincident with the antiresonance frequency of the ultrasonic transducer by self-oscillation of the
first waveform generation circuit. A plurality of signals having frequencies that are integral
multiples of the frequency of the drive voltage of the first waveform generation circuit by the
phase locked loop, and the second waveform generation circuit generates the plurality of signals.
One or a plurality of drive voltages having a predetermined phase difference with respect to the
drive voltage of the waveform generation circuit 1 are generated, and this drive voltage is
supplied to the other terminal of the ultrasonic transducer.
Thus, the ultrasonic transducer can be driven by a plurality of drive voltages having the
antiresonance frequency and waiting for a predetermined phase difference.
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[0018]
BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be
described in detail below.
[0019]
(First Embodiment) [Configuration] FIG. 1 is a circuit diagram of an ultrasonic transducer driving
apparatus according to a first embodiment of the present invention, and FIG. 2 is a signal
waveform diagram of each part of the driving apparatus.
[0020]
In the first embodiment, although the ultrasonic transducer is not particularly shown, the
piezoelectric ceramic 1 as a first terminal for applying a cross voltage to the ultrasonic
transducer, and the piezoelectric ceramic 11 as a second terminal. And is used.
[0021]
The drive device shown in FIG. 1 includes a first waveform generation circuit, a PLL (Phase
Locked Loop) circuit, and a second waveform generation circuit.
[0022]
The first waveform generation circuit includes a transformer 2 whose one end of a primary
winding is connected to a power supply (DC voltage source) 16, a transistor 3 whose other end of
the secondary winding of the transformer 2 is connected to a collector, A resistor 4 connected
between one end of the two primary windings and the base of the transistor 3 and a capacitor 5
connected between the base of the transistor 3 and the intermediate tap of the secondary
winding of the transformer 2 The piezoelectric ceramic 1 is connected to the secondary winding
of the transformer 2 to constitute a self-oscillation circuit which oscillates at the resonance
frequency of the ultrasonic transducer.
[0023]
The PLL circuit comprises a phase comparator 6, an integrator 7, a VCO (voltage controlled
oscillator) 8 and a frequency divider 9 connected in series, and the frequency divider 9 has a
phase difference of 90 degrees and a frequency input (VCO 8 Output of four signals of .phi.1 to
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.phi.4 which are 1/4 of the frequency.
The signal .phi.1 output from the frequency divider 9 is input to the phase comparator 6.
The phase comparator 6 is also connected to the base of the transistor 3 in the first waveform
generation circuit.
[0024]
The second waveform generation circuit includes a switch 10 for switching one of the signals φ2
and φ4 output from the divider 9 to select one, and a transistor 13 whose base is connected to
the switch 10 through a resistor 14 , A transformer 12 in which one end of a primary winding
and one end of a secondary winding are connected between the base resistor 15, the collector of
the transistor 13 and the input terminal (connection terminal to the power supply 16) of the first
waveform generation circuit. And the ceramic 11 is connected to the secondary winding of the
transformer 12.
[0025]
With such a configuration, alternating voltages, which are drive voltages, are applied to the two
piezoelectric ceramics 1 and 11 via the first and second waveform generation circuits,
respectively.
[0026]
Next, the operation of the drive unit will be described with reference to FIG.
[0027]
First, the operation of the self-oscillation circuit which is the first waveform generation circuit
will be described.
The transistor 3 is connected to the positive electrode by the resistor 4, and since the base
potential is higher than the emitter potential, the collector and the emitter are conducted.
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As a result, a current flows in the primary winding of the transformer 2, a boosted voltage is
generated on the secondary winding side, and a current flows in the piezoelectric ceramic 1.
[0028]
The output of the intermediate tap of the secondary winding of the transformer 2 is galvanically
isolated by the capacitor 5 and is input to the base of the transistor 3 as AC.
Then, the current flows from the resistor 4 in the direction of the capacitor 5 to raise the base
potential of the transistor 3 and the collector-emitter becomes nonconductive.
Then, the counter electromotive force generated in the secondary winding of the transformer 2
causes a current to flow in the ceramic 1 in the reverse direction to that described above.
At the same time, a current flows from the capacitor 5 in the direction of the resistor 4, the base
potential of the transistor 3 is increased, and the collector and the emitter conduct.
Self-oscillation occurs as a result of the above operation.
[0029]
The oscillation frequency at this time is a frequency that substantially matches the resonance
frequency fr of the ultrasonic transducer in which the feedback current flowing through the
resistor 4 and the capacitor 5 is large and the phase is 0 degree.
[0030]
Next, the operation of the PLL circuit will be described.
The base voltage of the transistor 3 is input to one input terminal of the phase comparator 6 as
.phi.o, and the signal .phi.1 which is one output of the frequency divider 9 is input to the other
input terminal of the phase comparator 6.
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The phase difference between the base voltage .phi.o and the signal .phi.1 is compared in the
phase comparator 6, and the result of the comparison is integrated in the integrator 7 to convert
this phase difference into the magnitude of the voltage. The VCO 8 changes its oscillation
frequency according to the output voltage of the integrator 7 and eventually stabilizes at a
frequency at which the phase difference between the base voltage .phi.o and the signal .phi.1
disappears, ie, the frequency at which the base voltage .phi.o and the signal .phi. .
[0031]
The frequency of the output of the VCO 8 is divided into 1⁄4 by the frequency divider 9 and input
to the phase comparator 6, so that the oscillation frequency of the VCO 8 is four times the
resonance frequency of the ultrasonic transducer. The waveforms of the base voltage .phi.o
described above, the output of the VCO 8 and the signals .phi.1 to .phi.4 are shown in FIG.
[0032]
The operation of the second waveform generation circuit is as follows. Since the output of the
VCO 8 is four times the frequency of the base voltage .phi.o, the waveforms of the signals .phi.1,
.phi.2, .phi.2, .phi.4 can be generated as shown in FIG. 2 with reference to the output waveform of
the VCO 8. The signals .phi.1, .phi.2, .phi.2, .phi.4 have the same frequency with respect to the
base voltage .phi.o, and the phase differences become 0 degrees, 90 degrees, 180 degrees and
270 degrees (-90 degrees), respectively. The changeover switch 10 selects a necessary phase
from among these.
[0033]
For example, the signal .phi.2 may be selected to generate a waveform having a phase difference
of +90 degrees with respect to the base voltage .phi.o, and the signal .phi.4 may be selected to
generate a waveform having a phase difference of -90 degrees. After one of the signals .phi.2 and
.phi.4 is selected by the changeover switch 10, the signal .phi.2 or .phi.4 is inputted to the base of
the transistor 13 through the resistor 14. If the base potential of the transistor 13 is higher than
the emitter potential, the collector-emitter is conducted, current flows in the primary winding of
the transformer 12, and current flows in the piezoelectric ceramic 11 by the voltage generated
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on the secondary winding side.
[0034]
If the base potential of the transistor 13 is lower than the emitter potential, the collector and the
emitter become nonconductive, and the reverse electromotive force generated on the secondary
winding side of the transformer 12 causes the piezoelectric ceramic 11 to reverse the direction
described above. Current flows.
[0035]
As described above, based on the base voltage .phi.o of the first waveform generation circuit, the
PLL circuit outputs waveforms having the same frequency but 90.degree. And 270.degree.
Different phases, which are selected by the second waveform generation circuit. The pressure is
raised to drive the piezoelectric ceramic 11.
[0036]
[Effect] According to the driving device of the first embodiment, the ultrasonic vibrator has a
plurality of driving voltages having the resonance frequency fr and waiting for any phase
difference of 90 degrees and 270 degrees (-90 degrees). Can be driven by
[0037]
Second Embodiment [Configuration] Next, the configuration of the second embodiment will be
described with reference to FIG.
FIG. 3 is a circuit diagram of the drive unit of the ultrasonic transducer according to the first
embodiment, and FIG. 2 is a signal waveform diagram of each part of the drive unit.
[0038]
In the second embodiment, although the ultrasonic transducer is not particularly shown, the
piezoelectric ceramic 21 as a first terminal for applying an alternating voltage to the ultrasonic
transducer and the ceramic 33 as a second terminal are used. It is configured using.
[0039]
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The drive device shown in FIG. 3 includes a first waveform generation circuit, a PLL circuit, and a
second waveform generation circuit.
[0040]
The first waveform generation circuit includes an NPN transistor 23 whose collector is connected
to a power supply (DC voltage source) 39, and a PNP transistor 24 whose emitter is connected to
the emitter of the transistor 23 and whose collector is grounded. A transistor 25 whose collector
is connected to each base of the transistors 23 and 24 and whose emitter is grounded, a resistor
26 connected between the collector and the base of the transistor 23, and one end of each
emitter of the transistors 23 and 24 An inductor 22 connected to the other end of the transistor
25 via a resistor 27 and a resistor 28 connected between the base of the transistor 25 and the
ground The piezoelectric ceramic 21 is connected to the other end, and self-excitation oscillates
at the anti-resonance frequency of the ultrasonic transducer. Constitute the oscillation circuit.
[0041]
The PLL circuit comprises a phase comparator 29, an integrator 30, a VCO (voltage control
oscillator) 31, and a frequency divider 32 connected in series, and the frequency divider 32 has a
phase difference of 30 degrees and an input frequency (of the VCO 31). Output Two signals of
φ5 to φ6 which are 1/12 of the frequency are outputted.
The signal .phi.5 output from the frequency divider 32 is input to the phase comparator 29. As
shown in FIG.
The phase comparator 6 is also connected to the bases of the transistors 23 and 24 in the first
waveform generation circuit.
[0042]
The second waveform generation circuit has an NPN type transistor 35 and a PNP type transistor
36 in which the signal φ 6 which is the output of the frequency divider 32 is input to each base
via the resistor 37. One end of an inductor 34 is connected to the connection point of each
emitter, and the piezoelectric ceramic 33 connected to the other end of the inductor 34 is driven.
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The collector of the transistor 35 is connected to the power supply 39.
In FIG. 3, reference numeral 38 denotes a base resistance of the transistors 35 and 36.
[0043]
With such a configuration, alternating voltages, which are drive voltages, are applied to the two
piezoelectric ceramics 21 and 33 by the first and second waveform generation circuits,
respectively.
[0044]
(Operation) Next, the operation of the second embodiment will be described.
[0045]
First, the operation of the self-oscillation circuit which is the first waveform generation circuit
will be described.
The transistor 23 conducts between the collector and the emitter because the base potential is
higher than the emitter potential by the resistor 26, and the transistor 24 does not conduct
between the collector and the emitter because the base potential is higher than the emitter
potential. .
At this time, the collector-emitter of the transistor 25 is nonconductive.
[0046]
As a result, current flows from the power supply 39 to the piezoelectric ceramic 21 through the
transistor 23 and the inductor 22 (hereinafter referred to as current flow in the positive
direction).
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Then, the potential at the connection point between the inductor 22 and the piezoelectric
ceramic 21 is increased, whereby the base potential of the transistor 24 is also increased, and the
collector-emitter of the transistor 25 is conducted.
[0047]
When the collector-emitter of transistor 25 becomes conductive, the base potential of transistor
23 becomes lower than the emitter potential, so that the collector-emitter of transistor 23
becomes nonconductive, and the base potential of transistor 24 becomes lower than the emitter
potential. Conduction is made between the collector and the emitter.
[0048]
At this time, the charge stored in the damping capacitance of the piezoelectric ceramic 21 moves
to the ground through the inductor 22 and the transistor 24, and the current flows (hereinafter
referred to as the flow of current in the negative direction).
As a result, the potential at the connection point between the inductor 22 and the piezoelectric
ceramic 21 is lowered, and the base potential of the transistor 24 is also lowered, so that the
collector-emitter of the transistor 25 becomes nonconductive. As a result, the collector-emitter of
the transistor 23 conducts and the collector-emitter of the transistor 24 does not conduct. Selfoscillation occurs by repeating the above.
[0049]
The oscillation frequency of the self-oscillation at this time is determined as follows. When the
flow of the current in the positive direction and the flow of the current in the negative direction
are repeated, the amplitude of the voltage at both ends of the piezoelectric ceramic 21 is mainly
determined by the voltage division ratio by the impedance of the inductor 22 and the
piezoelectric ceramic 21. Now, assuming that the frequency is constant, the impedance of the
inductor 22 is constant, so that the voltage amplitude is largest near the antiresonant frequency
(fa shown in FIG. 9) at which the impedance of the piezoelectric ceramic 21 becomes highest.
[0050]
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Therefore, if the values of the resistors 27 and 28 are selected so that the feedback amount of
positive feedback becomes appropriate, oscillation occurs in the vicinity of the antiresonance
frequency fa. More precisely, oscillation occurs at a frequency at which the phase of the feedback
current becomes 0 degrees in the vicinity of the antiresonance frequency fa.
[0051]
Next, the operation of the PLL circuit will be described. The base voltage of the transistors 23
and 24 is input to one input terminal of the phase comparator 29 as φ0, and the signal φ5
which is one output of the frequency divider 32 is input to the other input terminal of the phase
comparator 29 .
[0052]
The phase difference between the base voltage .phi.0 and the signal .phi.5 is compared by the
phase comparator 29, and the result of the comparison is integrated by the integrator 30,
whereby this phase difference is converted into the magnitude of the voltage. The oscillation
frequency of the VCO 31 is changed by the output voltage of the integrator 30, and finally, when
the phase difference between the base voltage φ 0 and the signal φ 5 disappears, that is, the
frequencies of the base voltage φ 0 and the signal φ 5 coincide When it stabilizes.
[0053]
The frequency of the output of the VCO 31 is divided by 1/12 by the frequency divider 32 and
input to the phase comparator 29, so that the oscillation frequency of the VCO 31 is 12 times the
resonance frequency of the ultrasonic transducer. The waveforms of the base voltage .phi.0
described above, the output of the VCO 31, and the signals .phi.5 and .phi.6 are as shown in FIG.
[0054]
Next, the operation of the second waveform generation circuit is as follows. Since the output of
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the VCO 31 is 12 times the frequency of the base voltage φ 0, a signal of an arbitrary waveform
can be generated at intervals of 360 ° ÷ 12 = 30 ° based on the output waveform of the VCO
31. Here, when a signal .phi.6 whose phase is delayed by 30 degrees with respect to the base
voltage .phi.0 is generated, the timing as shown in FIG. 4 is obtained.
[0055]
When this signal .phi.6 is inputted to the base of the transistors 35, 36 through the resistor 37,
when the signal .phi.6 is high, the collector-emitter of the transistor 35 conducts, and the
collector-emitter of the transistor 36 It becomes non-conductive, and current flows from the
power supply 39 to the piezoelectric ceramic 33 through the transistor 35 and the inductor 34.
[0056]
When the signal φ6 is low, the collector-emitter of the transistor 35 is not conductive, and the
collector-emitter of the transistor 36 is conductive, and the piezoelectric ceramic 33 is connected
to the ground via the inductor 34 and the transistor 36. A current flows.
[0057]
As described above, in the second embodiment, the first waveform generation circuit and the
second waveform generation circuit match or substantially match the antiresonance frequency of
the ultrasonic transducer, and the driving voltage differs in phase by 30 degrees. Can generate
[0058]
(Effects) In the drive device according to the second embodiment, the ultrasonic transducer can
be driven by two drive voltages having an antiresonance frequency and waiting for a phase
difference of 30 degrees.
[0059]
According to the first aspect of the present invention, there is provided a drive device capable of
driving the ultrasonic transducer by a plurality of drive voltages having the same phase as and
different from the resonance frequency of the ultrasonic transducer. be able to.
[0060]
According to the second aspect of the present invention, it is possible to provide a drive device
capable of driving the ultrasonic transducer by a plurality of drive voltages which coincide with
the anti-resonance frequency of the ultrasonic transducer and have different phases.
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[0061]
Brief description of the drawings
[0062]
1 is a circuit configuration diagram of a drive device for an ultrasonic transducer according to
Embodiment 1 of the present invention.
[0063]
2 is a signal waveform diagram of each part of the drive device of Embodiment 1 of the present
invention.
[0064]
3 is a circuit configuration diagram of a drive device of the ultrasonic transducer of the second
embodiment of the present invention.
[0065]
4 is a signal waveform diagram of each part of the drive device of Embodiment 2 of the present
invention.
[0066]
5 is a circuit diagram showing a basic configuration of the oscillation circuit.
[0067]
6 is an oscillation waveform diagram of the oscillation circuit shown in FIG.
[0068]
7 is an explanatory view showing the relationship between the transfer amount of the oscillation
circuit shown in FIG. 5 and the frequency.
[0069]
8 is an equivalent circuit diagram of the ultrasonic transducer.
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[0070]
9 is an explanatory view showing the relationship between the impedance of the equivalent
circuit of the ultrasonic transducer and the frequency.
[0071]
10 is an explanatory view showing the relationship between the phase and the frequency of the
equivalent circuit of the ultrasonic transducer.
[0072]
11 is a circuit diagram showing a conventional self-excitation transmission circuit.
[0073]
Explanation of sign
[0074]
Reference Signs List 1 piezoelectric ceramic 2 transformer 3 transistor 4 resistor 6 phase
comparator 7 integrator 8 VCO 9 divider 10 switch 11 piezoelectric ceramic 12 transformer 13
transistor 16 power supply 21 piezoelectric ceramic 22 inductor 23 transistor 24 transistor 25
transistor 33 piezoelectric ceramic 34 inductor 35 Transistor 36 transistor 39 power supply
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