WO2003033174A1

WO2003033174A1 - Ultrasonic oscillator drive apparatus

Info

Publication number: WO2003033174A1
Application number: PCT/JP2002/010698
Authority: WO
Inventors: Hiroaki Nagata
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2001-10-17
Filing date: 2002-10-15
Publication date: 2003-04-24
Also published as: KR20050036869A; KR100575508B1; JP2003117485A; CN1571705A; TW550121B

Abstract

An ultrasonic oscillator drive apparatus includes a phase delay circuit composed of a time constant circuit, a microcomputer for detecting flowing current of the ultrasonic oscillator, and a phase adjusting circuit for varying the time constant of the phase delay circuit according to an instruction of the microcomputer. The phase adjusting circuit is controlled so as to minimize the flowing current of the ultrasonic oscillator. With this configuration, it is possible to obtain optimal drive of the ultrasonic oscillator without manually performing phase adjustment

Description

Description Ultrasonic transducer drive Technical field

The present invention relates to an ultrasonic transducer driving device having a phase lock circuit for fixing a driving phase of an ultrasonic transducer. Background art

A conventional ultrasonic vibrator driving device has a phase locked circuit (PLL [Phase-Locked-Loop] circuit), as disclosed in Japanese Patent Application Laid-Open No. 63-123746. What is made is common. In such a conventional ultrasonic vibrator driving device, the driving phase of the ultrasonic vibrator is fixed so that the driving frequency of the ultrasonic vibrator is between the resonance frequency and the anti-resonance frequency. Control is performed.

However, in the conventional ultrasonic vibrator driving device having the above configuration, since the drive I phase of the ultrasonic vibrator is fixed at the time of the initial adjustment, if the circuit constant changes due to a temperature change or aging of circuit components. There is a problem that the driving phase is shifted and the driving frequency of the ultrasonic vibrator does not fall within an appropriate range. An ultrasonic transducer driving device that can manually adjust the phase has also been proposed.However, since the resonance frequency and the like may change due to a rise in the temperature of the ultrasonic transducer in use, the driving phase may be deviated. Frequently it was necessary to redo the phase adjustment. In particular, with ultrasonic transducer assemblies with high Q, the difference between the resonance frequency and the anti-resonance frequency was small, and even a small drive phase shift drastically changed the drive phase, which had a large effect on performance. Disclosure of the invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic vibrator driving device capable of always optimally driving an ultrasonic vibrator without requiring phase adjustment by a user. I do.

In order to achieve the above object, an ultrasonic transducer driving device according to the present invention comprises: In an ultrasonic transducer driving device having a phase fixing circuit for fixing a driving phase of a moving element, the phase is determined based on a conduction current of the ultrasonic transducer or a conduction current substitute signal indicating equivalent behavior. The drive phase of the ultrasonic transducer fixed by the fixing circuit is automatically adjusted. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram showing an embodiment of an ultrasonic transducer driving device according to the present invention, and FIG. 2 is a circuit diagram (a) showing an embodiment of a phase delay circuit 1 and points A to C in respective parts. FIG. 3 is a diagram illustrating impedance characteristics of the ultrasonic vibrator 10 and the choke coil 9, and FIG. 4 is a diagram illustrating an embodiment of the phase delay circuit 1 and the second phase adjustment circuit 15. FIG. 5 is a flowchart illustrating the automatic adjustment operation of the drive phase by the microcomputer 12. BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a block diagram showing an embodiment of an ultrasonic transducer driving device according to the present invention. As shown in the figure, the ultrasonic transducer driving device according to the present embodiment includes a phase delay circuit 1 for giving a predetermined phase delay to an input pulse signal, and a pulse signal output from the phase delay circuit 1. Inverted signal generation circuit 2 for inverting logic, first and second drivers 3 and 4 for outputting pulse signals whose logic is inverted, inverter circuit 5 for generating AC voltage from DC voltage, and specific frequency components Band-pass adjustment filter 6 that passes only the signal, a first phase adjustment circuit 7 that performs phase adjustment based on the output signal of the band-pass adjustment filter 6, and an analog signal output from the first phase adjustment circuit 7 as a digital pulse signal. A zero-crossing panless conversion circuit 8, a choke coil 9, an ultrasonic vibrator 10 and a current transformer for detecting a current flowing through the ultrasonic vibrator 10 as a voltage signal. A microcomputer 12 that controls the automatic adjustment of the drive phase based on the voltage signal obtained by the current transformer 11, a nonvolatile memory 13 that retains the stored contents even when power is not supplied, A notification unit 14 including a light emitting diode pumper and the like, and a second phase adjustment circuit 15 for adjusting the phase of the phase delay circuit 1 in accordance with an instruction from the microcomputer 12 are provided. Note that the current flowing through the ultrasonic vibrator 10 is detected. As an alternative, a Hall element or other current detector may be used instead of the current transformer 11. -The inverter circuit 5 includes FETs 51, 52, a double insulating transformer 53, and a resistor 54. The gates of the FETs 51 and 52 are connected to the output terminals of the first and second drivers 3 and 4, respectively. The sources of the FETs 51 and 52 are grounded via the resistor 54 and are also connected to the primary-side current detection terminal of the microcomputer 12.

The double insulating transformer 53 includes coils 53a, 53b, 53c and a core 53d that magnetically couples the coils. One end of the coil 53 a is connected to the drain of FET 51, and the other end is connected to the drain of FET 52. The center tap of the coil 53a is connected to the load power supply. A series circuit including the choke coil 9 and the ultrasonic vibrator 10 is connected between both ends of the coil 53b. Both ends of the coil 53 c are connected to the input terminals of the pan-pass adjustment filter 6. The double insulation transformer 5 was used to strengthen the insulation between the primary side and the secondary side. If it is not necessary to use insulation reinforcement, use a normal insulation transformer. Note that, in the ultrasonic vibrator driving device of the present embodiment, all the power to the ultrasonic vibrator 10 and the control system circuit is externally supplied. Further, a start instruction and a stop instruction to the microcomputer 12 are performed by communication with the outside. However, it is also possible for the user to directly operate with a key switch (not shown) connected to the microcomputer 12 or the like. Next, the operation of the ultrasonic transducer driving device having the above configuration will be described. FIG. 2 is a circuit diagram (a) showing an embodiment of the phase delay circuit 1 and a voltage waveform diagram (b) at points A to C of each section. As shown in the figure, the phase delay circuit 1 of the present embodiment is a fixed delay circuit including logic circuits IC 1 and IC 2, a capacitor C 1, and a resistor R 1. However, the configuration of the phase delay circuit 1 is not limited to this, and another method may be used.

When the ultrasonic transducer driving device of the present embodiment is operating, a pulse signal having a period T is input from the zero-cross pulse conversion circuit 8 to the point A of the phase delay circuit 1. When the potential at the point A (that is, the input to the logic circuit IC1) changes from Low to High, the output of the logic circuit IC1 changes from High to Low, and the charging voltage of the capacitor C1 passes through the resistor R1. And discharged to the output of the logic circuit IC1. Therefore, the potential at point B Changes from High to Low with a predetermined time constant. At this time, if the potential at the point B falls below the threshold level of the logic circuit IC2, the input of the logic circuit IC2 is turned off from High. It becomes w, and the output of the logic circuit IC 2 is inverted from Low to High. That is, in the phase delay circuit 1, the logical inversion of the potential at the point C with respect to the potential at the point A is delayed by the time t1 due to the time constant of the capacitor C1 and the resistance R1. As a result, a phase difference corresponding to time t1 occurs in the drive phase of the ultrasonic oscillator 10. Also, when the input of the logic circuit IC1 changes from High to Low, the logic inversion of the potential at the point C with respect to the potential at the point A is delayed by the time t1 to generate a phase difference, similarly to the above.

The inverted signal generation circuit 2 logically inverts the pulse signal output from the phase delay circuit 1 and supplies the inverted signal to the second driver 4. As a result, the first and second drivers 3 and 4 each output a signal whose logic is inverted, so that the FETs 51 and FET 52 constituting the skipper circuit 5 are turned on alternately. Therefore, the current from the load power supply alternately flows through the center tap of the coil 53a to the FETs 51 and 52, so that the direction of the current flowing through the coil 53a is repeatedly reversed, and the secondary side An AC voltage is induced in the coil 53b. The secondary current obtained by the coil 53 b is supplied to the ultrasonic vibrator 10 via the choke coil 9.

At this time, a voltage signal indicating the driving phase current waveform of the ultrasonic transducer 10 is generated in the coil 53 c of the double insulating transformer 53, and the voltage signal is sent to the bandpass adjustment filter 6. However, since the winding directions of the coils 53b and 53c are different, the voltage phase generated in the coil 53c is opposite to the secondary current by 180 degrees. As described above, the band-pass adjustment filter 6 allows only a specific frequency component to pass. The band-pass adjustment filter 6 according to the present embodiment is composed of a parallel circuit of a coil and a capacitor (not shown), and by adjusting the inductance of the coil divided by the capacitance of the capacitor, the ultrasonic transducer 1 At a desired frequency including a range between the resonance frequency of 0 and the antiresonance frequency, the impedance of the bandpass adjustment filter 6 is adjusted to be the lowest. Therefore, of the frequency components included in the voltage signal input from the coil 53 c, the frequency components other than the resonance frequency and the anti-resonance frequency of the ultrasonic vibrator 10 are attenuated by the bandpass adjustment filter 6. However, the internal configuration of the bandpass adjustment filter 6 is limited to a parallel circuit of a coil and a capacitor. However, other methods may be used.

The output signal of the band-pass adjustment filter 6 is input to the first phase adjustment circuit 7. The first phase adjusting circuit 7 adjusts the phase difference so as to keep the phase difference of the entire loop at 180 degrees, together with the phase delay circuit 1 that creates a fixed phase difference.

The above-described band-pass adjustment filter 6 and first phase adjustment circuit 7 are generally initially adjusted at the time of production of the ultrasonic vibrator driving device, and thereafter are often used with fixed values. In the ultrasonic transducer driving device capable of manually performing the adjustment, the first phase adjustment circuit 7 is often adjusted.

The zero-cross pulse conversion circuit 8 is a circuit that converts the sine-wave analog signal output from the first phase adjustment circuit 7 into a digital pulse signal whose High / Low is inverted at 50% duty with reference to the zero-cross potential. This has the purpose of simplifying the subsequent signal processing. In addition, since the drive phase can be automatically adjusted with the pulsed digital signal, automatic adjustment with high accuracy that is less affected by signal voltage fluctuations can be realized. Note that the digital pulse signal generated by the zero-cross pulse conversion circuit 8 is sent to the phase delay circuit 1 as described above.

As described above, the phase delay circuit 1, the inversion signal generation circuit 2, the first and second drivers 3, 4, the inverter circuit 5, the bandpass adjustment filter 6, the first phase adjustment circuit 7, The zero-cross pulse conversion circuit 8 forms a PLL closed circuit that fixes the drive phase of the ultrasonic transducer 10. In the ultrasonic transducer driving device of the present embodiment, elements having a large effect on the drive phase fluctuation of the ultrasonic transducer 10 include a capacitor in the phase delay circuit 1 and a capacitor in the bandpass adjustment filter 6. And a capacitor in the first phase adjustment circuit 7. Next, the impedance characteristics of the ultrasonic vibrator 10 and the choke coil 9 will be described. 3A and 3B are diagrams for explaining the impedance characteristics of the ultrasonic vibrator 10 and the choke coil 9. FIG. 3A shows the impedance characteristic of the ultrasonic vibrator 10 alone, and FIG. The phase angle characteristics of the series circuit composed of the choke coil 9 are shown, and (c) shows the impedance characteristics of the series circuit composed of the ultrasonic vibrator 10 and the choke coil 9. The horizontal axes of (a) to (c) indicate frequencies, and the right side of the paper is the high frequency side. The drive frequency of the ultrasonic vibrator 10 is desirably between the resonance point and the anti-resonance point, as shown in FIG. On the other hand, the maximum point of the series circuit impedance consisting of the ultrasonic vibrator 10 and the choke coil 9 (see (c) in the figure) is the point where the phase angle becomes 0 degree.

(See (b) in the figure), which is the minimum point of the current flowing in the series circuit composed of the ultrasonic vibrator 10 and the choke coil 9. At this time, since the voltage signal induced in the secondary coil of the current transformer 11 also has a minimum value, if the minimum value of the voltage signal is found, the ultrasonic transducer 10 is always driven in an optimum state. The reference point (reference frequency) for the can be determined.

As described above, the frequency at which the current flowing through the ultrasonic torsion element 10 becomes minimum is the frequency at which the phase angle of the series circuit composed of the ultrasonic vibrator 10 and the choke coil 9 becomes 0 degree, and Since the impedance is the highest, it is optimal as a reference point for the drive phase, and can achieve accurate automatic calibration.

Subsequently, a detailed description will be given of the configuration for performing the phase adjustment described above. FIG. 4 is a circuit diagram showing an embodiment of the phase delay circuit 1 and the second phase adjustment circuit 15. The second phase adjustment circuit 15 of the present embodiment includes a switch SW a, SW b, SW c and an adjustment resistor Ra, R b, R c in parallel with the resistor R 1 constituting the phase delay circuit 1. It consists of three series circuits connected. With such a configuration, by performing on / off control of the switches SWa to SWc, the adjusting resistors Ra to Rc can be incorporated into the phase delay circuit 1 in eight combinations.

As described above, the time constant of the phase delay circuit 1 is determined by the capacitance value and the resistance value of the circuit, and a phase difference t 1 corresponding to the time constant occurs in the driving phase of the ultrasonic vibrator 10. . Therefore, if the switches SW a to SW c of the second phase adjustment circuit 15 are turned on and off by the microcomputer 12, the resistance value that determines the time constant of the phase delay circuit 1 can be changed, and the result is Thus, it is possible to adjust the phase difference t1 generated in the drive phase of the ultrasonic vibrator 10.

In addition, since adjustment is performed using a simple CR time constant circuit using capacitors and resistors, the circuit configuration can be simplified and cost advantages can be realized. In addition, because the method of searching for the optimal drive phase by changing the capacitance value or the resistance value is less susceptible to errors and aging of the capacitors and resistors that constitute the phase delay circuit 1 and the second phase adjustment circuit 15. Automatic adjustment 02 10698 1 7-Adjustment can be realized.

Note that the configuration of the second phase adjustment circuit 15 is not limited to the above, and the configuration in which the number of combinations of switches and adjustment resistors is increased or decreased, or the configuration in which the resistance R 1 of the phase delay circuit 1 is connected in series with the resistor R 1 Various changes are possible, such as a configuration in which an adjusting resistor is inserted. Although not shown, an adjustment capacitor may be connected in parallel (or in series) to the capacitor C1 of the phase delay circuit 1 to change the capacitance value. Further, in the second phase adjustment circuit 15 of the present embodiment, the contact switches are used as the switches SWa to SWc for switching the connection of the adjustment resistors R a to R c, but the type of the switches is not limited to this. Instead, a semiconductor switching element such as an FET, an IC containing a plurality of FETs, or an IC that can change the resistance value by communication control can be used. Of course, the same is true when switching the capacitance value. Next, the operation for automatically adjusting the driving phase will be described. FIG. 5 is a flowchart for explaining the automatic adjustment operation of the drive phase by the microcomputer 12. In the following, a description will be given of a configuration in which the resistance value of the phase delay circuit 1 is changed to adjust the drive phase of the ultrasonic vibrator 10 as an example, and the description of the change in the capacitance value is omitted. The drive phase of the ultrasonic transducer 10 is determined by the current supplied to the ultrasonic transducer 10 (the voltage signal output from the current transformer 11) or the current-current substitute signal (resistance The automatic adjustment is performed by detecting the primary-side current signal of the double-insulated transformer 53 that has been voltage-converted in 54. In the following, the phase is adjusted based on the voltage signal output from the current transformer 11 The case where the adjustment operation is performed will be described as an example, and the description of the other configuration for detecting the current-carrying-current alternative signal is omitted.

First, in step F1, when the operation of the ultrasonic vibrator 10 is started, in the subsequent step F2, the microcomputer 12 instructs the notification unit 14 to drive the ultrasonic vibrator 10 now. An instruction is sent to notify that the phase is being automatically adjusted, and the notification unit 14 that receives the instruction performs lighting / flashing of the light emitting diode, buzzer output, and the like. By such a notification operation, the user can confirm that it is necessary to wait for a while to use the ultrasonic vibrator 10, thereby increasing the convenience.

In addition, if the configuration is such that the drive phase is automatically adjusted immediately after the operation of the ultrasonic vibrator 10 is started, not only changes over time but also temperature conditions at that time will be minimized. Appropriate automatic adjustment is achieved, and the performance of the ultrasonic vibrator 10 can always be ensured. Then, in step F3, the setting state of the resistance value (or a previously registered initial value) determined at the previous adjustment is read out from the nonvolatile memory 13 connected to the microcomputer 12 and the following step F At 4, the previously determined value is set as the initial resistance value at the start of this automatic adjustment. With the configuration in which the automatic adjustment is started using the previously determined value as the reference value, the time required for the automatic adjustment can be reduced. In addition, by storing the previously determined value in the nonvolatile memory 13, even if the power supply to the microcomputer 12 is cut off, the previously determined value can be called when the microcomputer 12 is supplied with power again.

Thereafter, in step F5, when the oscillation of the ultrasonic transducer driving device is started, in step F6, the voltage signal of the current transformer 11 in the above state is detected. Further, in the following step F7, by switching the switches SWa to SWc, the resistance value of the phase delay circuit 1 is decreased in the direction in which the drive frequency of the ultrasonic vibrator 10 is lowered (delay time in the phase delay circuit 1). In the following step F8, the output voltage signal of the current transformer 11 in this state is detected.

Then, in step F9, the voltage signal detected in step F6 is compared with the voltage signal detected in step F8. Here, if the voltage signal at step F8 is lower than the voltage signal at step F6, the flow proceeds to the following step F10, and if not, the flow proceeds to step F16.

If it is determined in step F9 that the voltage signal has dropped, it means that the current drive frequency is approaching the reference frequency between the resonance frequency and the anti-resonance frequency of the ultrasonic vibrator 10. . Therefore, in step F10, the resistance value of the phase delay circuit 1 is switched one step lower, and in the subsequent step F11, the output voltage signal of the current transformer 11 in this state is detected.

Then, in step F12, the voltage signal detected in step F8 is compared with the voltage signal detected in step F11. Here, if the voltage signal in step F11 is lower than the voltage signal in step F8, the flow proceeds to the following step F13, and if not, the flow proceeds to step F21. When it is determined in step F12 that the voltage signal has further decreased, in step F13, it is determined whether or not the switching state of the switches SWa to SWc is the minimum setting. Here, if the switching state of the switches SWa to SWc is not the minimum setting, the flow returns to the above-described step F10, and the current driving frequency is set between the resonance frequency and the anti-resonance frequency of the ultrasonic vibrator 10. , The resistance of the phase delay circuit 1 is switched one step lower.

On the other hand, as the resistance value change (F10) of the phase delay circuit 1 and the voltage signal detection Z comparison (F11, F12) of the current transformer 11 are repeated, the switches SWa to SWc are switched. If the state has reached the minimum setting, in step F13, it is determined that the resistance value of the phase delay circuit 1 cannot be set any lower, and the flow proceeds to the subsequent step F14.

Originally, the ultrasonic vibrator driving device is designed such that the reference frequency between the resonance frequency and the antiresonance frequency of the ultrasonic vibrator 10 is within the switching range of the switches SWa to SWc. Therefore, if the output voltage of the current transformer 11 is still lower than immediately before, even though the switches SWa to SWc are at the minimum setting, it can be determined that some sort of component failure has occurred. Therefore, in step F14, the oscillating operation of the ultrasonic transducer driving device is stopped, and in subsequent step F15, an error display (notification) is performed. Thereafter, the above-described series of adjustment operations is terminated. In this way, when a problem occurs in the automatic adjustment means of the drive phase, the operation is stopped and an error is displayed (notified), so that the user can accurately recognize the state of the malfunction of the automatic adjustment means. can do.

On the other hand, if it is determined in step F9 that the voltage signal in step F8 is higher than the voltage signal in step F6, the current driving frequency is changed to the resonance frequency of the ultrasonic vibrator 10. It means that it is far from the reference frequency between and the anti-resonance frequency. Therefore, in step F16, the resistance value of the phase delay circuit 1 is switched to two steps higher (that is, one step higher than the previously determined value read in step F3), and the subsequent step F1 At 7, the output voltage signal of the current transformer 11 in this state is detected.

Then, in step F18, the voltage signal detected in step F6 and the step A comparison is made with the voltage signal detected at step F17. Here, if the voltage signal at step F17 is lower than the voltage signal at step F6, the flow proceeds to the following step F19, and if not, the flow proceeds to step F'21.

When it is determined in step F18 that the voltage signal has dropped, in step F19, it is determined whether or not the switching state of the switches SWa to SWc is at the maximum setting. Here, if the switching state of the switches SWa to SWc is not the highest setting, the flow proceeds to step F20, and the current drive frequency is set to a reference between the resonance frequency of the ultrasonic vibrator 10 and the anti-resonance frequency. In order to approach the frequency, the resistance of phase delay circuit 1 is switched one step higher. Thereafter, the flow returns to step F17 described above.

On the other hand, as the resistance value change (F20) of the phase delay circuit 1 and the voltage signal detection comparison (F17, F18) of the current transformer 11 are repeated, the switching state of the switches SWa to SWc is changed. If is set to the highest value, in step F19, it is determined that the resistance value of the phase delay circuit 1 cannot be set any higher, and the flow proceeds to step F14 described above. Then, in steps F14 and F15, the oscillation operation of the ultrasonic vibrator driving device is stopped and an error display (notification) is performed, and the above-described series of adjustment operations is completed.

If it is determined in step F12 or F18 that the current voltage signal is higher than the immediately preceding voltage signal, the immediately preceding driving frequency is higher than the current driving frequency. This also means that the reference frequency was close to the reference frequency between the resonance frequency and the anti-resonance frequency of the ultrasonic transducer 10. Therefore, in step F21, the immediately preceding resistance value of the phase delay circuit 1 is set as the final value, and in the following step F22, the previous final value in the nonvolatile memory 13 is rewritten with the final value.

However, if the variable resolution of the resistance value in the phase delay circuit 1 is low, the drive frequency of the ultrasonic vibrator 10 may not always be the optimal frequency with the switch setting determined in step F21. . Therefore, in step F23, a correction such as raising or lowering the reference frequency determined in step F21 by one step is performed as necessary. Note that information necessary for the correction operation (for example, a correlation between the resistance value and the driving frequency) may be stored in the microcomputer 12 in advance. Then, when the automatic adjustment of the driving phase is completed in step F24, in subsequent step F25, the light emitting diode in the notification unit 14 is turned off, the buzzer output is stopped, and the like. Then, the ultrasonic transducer driving device shifts to the normal operation.

As described above, in the ultrasonic vibrator driving device of the present embodiment, the microcomputer 12 detects the current flowing through the ultrasonic vibrator 10 and digitally determines the capacitance value or the current value based on the current value. Since the resistance value is changed, there is no analog judgment error and automatic adjustment by control software can be realized.

Although not shown in FIG. 5, only the current transformer 11 that detects the current flowing through the ultrasonic vibrator 10 fails even if the final value cannot be determined in the above automatic adjustment operation. In some cases, the oscillation operation can be continued by setting the previously determined value or the initial value read in step F3 as a tentative determined value. By adopting such a configuration, even if a problem occurs in the automatic adjusting means, it is possible to operate the apparatus for a while until repair.

Similarly, although not shown in FIG. 5, in the above-described automatic adjustment operation, even if the determined value cannot be determined, it is also possible to return to step F4 and perform the automatic adjustment again. . With such a configuration, more stable automatic adjustment can be realized. Industrial applicability

The ultrasonic transducer driving device according to the present invention is preferably applied to all apparatuses having an ultrasonic transducer (such as an ultrasonic cleaning machine). ADVANTAGE OF THE INVENTION According to this invention, the optimal drive phase of the ultrasonic transducer which was initially adjusted will shift | deviate by the temperature change of the components of an ultrasonic vibrator and an ultrasonic vibrator drive device, or the aging of components over a long period. Even if it does, there is no need to make manual adjustments depending on the intuition of the user. Therefore, not only is the convenience very high for the user, but also the performance can be maintained for various conditions and long-term conditions. In addition, when the Q of the ultrasonic vibrator is low (that is, when the difference between the resonance frequency and the antiresonance frequency is large), in addition to the above, the initial phase lock circuit (band-pass adjustment filter or phase adjustment circuit) is added. No adjustment is required. Therefore, there is also an advantage that the production efficiency of the ultrasonic transducer driving device can be greatly improved.

Claims

The scope of the claims '

1. An ultrasonic transducer driving device having a phase fixing circuit for fixing the driving phase of the ultrasonic transducer,

A drive phase of the ultrasonic vibrator fixed by the phase fixing circuit is automatically adjusted based on a current flowing through the ultrasonic vibrator or a current-supplying current signal showing an equivalent behavior. Sonic vibrator drive.

2. The ultrasonic vibrator drive according to claim 1, wherein the drive phase of the ultrasonic vibrator is automatically adjusted by changing a time constant of a CR time constant circuit constituting the phase lock circuit. apparatus.

3. It has a microcomputer which detects a current flowing through the ultrasonic vibrator or a current alternative signal showing an equivalent behavior, and changes a time constant of the CR time constant circuit according to a command from the microcomputer. 3. The ultrasonic transducer driving device according to claim 2.

4. The microcomputer changes a time constant of the CR time constant circuit so that a current flowing through the ultrasonic vibrator or a current-carrying alternative signal exhibiting an equivalent behavior is minimized. 4. The ultrasonic transducer driving device according to 3.

5. It has a non-volatile memory that retains the stored contents even when the power is not supplied, and the data corresponding to the new drive phase obtained by the automatic adjustment of the drive phase is used as the fixed value by the automatic adjustment. 2. The ultrasonic transducer driving device according to claim 1, wherein the ultrasonic transducer driving device is stored in a nonvolatile memory.

6. The ultrasonic transducer driving device according to claim 5, wherein the automatic adjustment of the driving phase is performed with reference to a previously determined value stored in the nonvolatile memory.

7. If the drive phase automatic adjustment is not completed, store it in the nonvolatile memory. 7. The ultrasonic transducer driving device according to claim 6, wherein the previously determined value or the previously registered initial value is set as a tentative determined value.

8. The ultrasonic vibrator driving device according to claim 1, wherein, when the automatic adjustment of the driving phase is not completed, a notification to that effect is made and the driving of the ultrasonic vibrator is stopped. .

9. The ultrasonic transducer according to claim 8, wherein when the drive of the ultrasonic transducer is stopped, the drive of the ultrasonic transducer is restarted after a predetermined period, and the automatic adjustment of the drive phase is attempted again. Sonic vibrator drive.

10. The ultrasonic transducer driving device according to claim 1, wherein the automatic adjustment of the driving phase is performed based on a pulse-converted digital phase signal.

11. The ultrasonic vibrator driving device according to claim 1, wherein the automatic adjustment of the driving phase is performed immediately after the driving of the ultrasonic vibrator is started.

12. The ultrasonic vibrator driving device according to claim 1, wherein a notification is given during automatic adjustment of the driving phase.