JPH11356066A - Drive for capacitive load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive unit for a capacitive load for easily generating a control signal by a digital IC and controlling it and to further reduce its size by supplying a driving voltage of a high potential to the load even without using a step-up transformer at an output. SOLUTION: The drive unit 23A for a capacitive load connected to a connecting point 27 of a PNP transistor TR1 and an NPN transistor TR2 comprises the PNP transistor TR1 of a complementary type first switching element, and the NPN transistor TR2 of a second switching element connected in series with each other between a first power source +30 V and a second power source -30 V, and two diodes D1 and D2 connected in series between the power source +30 V and the power source -30 V to respectively supply currents to the transistors TR1 and TR2 in a unidirection according to the voltages applied to the transistors TR1 and TR2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a driving device for a capacitive load, for example, a driving device for driving a capacitive load such as a piezoelectric element in a vibration actuator.

[0002]

2. Description of the Related Art For example, a piezoelectric element is joined to the surface of an elastic body, and a drive voltage is applied to the piezoelectric element to generate a plurality of vibration modes in the elastic body in harmony. There is known a vibration actuator that generates an elliptical motion and drives a relative motion member that is brought into pressure contact with the elastic body. Among these types of vibration actuators, those utilizing an ultrasonic vibration range are called ultrasonic vibration actuators or ultrasonic motors.

In driving the ultrasonic actuator, generally, a driving ultrasonic power source is a low-potential DC power source which is switched by a semiconductor and is boosted to a high voltage by a boosting transformer.

FIG. 6 shows a driving device 1 using a step-up transformer.
FIG. 3 is a block diagram showing the configuration of FIG. As shown in FIG. 1, in the driving device 1, the driving signal output from the oscillation circuit 2 is sent to the phase shift circuit 3, and the phase shift circuit 3 causes the A-phase drive signal and the A-phase to have a phase. (Π / 2) shifted B-phase drive signals. These drive signals are switched by switching elements 4a and 4b using semiconductors, respectively, and further boosted to a high voltage by boosting transformers 5a and 5b. Then, two types of drive signals are input to the piezoelectric element of the ultrasonic actuator 6.

However, since the driving device 1 shown in FIG. 6 is an open loop, and the step-up transformers 5a and 5b have impedances due to windings, a current change due to a load fluctuation of the ultrasonic actuator induces a change in the output voltage. As a result, speed fluctuations, torque fluctuations, and the like are caused, and various control performances of the ultrasonic actuator are reduced.

Incidentally, the piezoelectric element of the ultrasonic actuator 6 can be treated as a capacitive load in an equivalent circuit. Among such capacitive load driving devices, a device which directly controls a high voltage by using a semiconductor element is proposed in, for example, Japanese Patent Application Laid-Open No. 9-9650.

FIG. 7 is an explanatory diagram of a driving device according to this proposal. The capacitive load driving device 7 controls the voltage follower 8 from the control signal Ve which fluctuates up and down around 0V.
Is output to charge and discharge the capacitive load 9 as a piezoelectric element. That is, the control signal Ve from the voltage follower 8 is applied to the ground terminal 10 by +0.6 V
When the level exceeds this level, a base current starts flowing between the base and the emitter of the NPN transistor 11, and a collector current flows accordingly. This collector current becomes the base current of the PNP transistor 12, and the collector current of the PNP transistor 12 flows according to the base current, and the driving voltage is supplied from the positive power supply 13 to the capacitive load 9. At this time, the control signal Ve is also applied to the PNP transistor 14, but since it is about 0.6 V or more, the base current does not flow and the PNP transistor 14 does not differentially operate. If the PNP transistor 14 does not operate, the base current does not flow to the NPN transistor 15 and the NPN transistor 15 is off.

Next, when the control signal Ve from the voltage follower 8 falls below about -0.6 V with respect to the ground terminal 10, a base current flows between the emitter and the base of the PNP transistor 14, and a collector current flows accordingly. . This collector current becomes a base current of the NPN transistor 15, and a collector current flows through the NPN transistor 15 in accordance with the base current, and the potential charged in the capacitive load 9 is discharged toward the negative power supply 16 and in the reverse direction. Is charged. That is, a negative drive voltage is supplied from the negative power supply 16 to the capacitive load 9. At this time, the control signal Ve is also applied to the NPN transistor 11, but since it is about -0.6 V or less, the base current does not flow and the NPN transistor 11 does not operate. NPN
If the transistor 11 does not operate, the PNP transistor 1
2, no base current flows, and the PNP transistor 12 is off.

In this manner, the output signal of the voltage follower 8 having a low potential causes the capacitive load 9 to be connected to the power supplies 13 and 1.
6 can be supplied.
Although it depends on the breakdown voltage of the transistor and the like, a driving voltage of several hundred volts can be controlled. Therefore, by applying this kind of capacitive load driving device to the ultrasonic actuator, it is not necessary to use the above-described step-up transformers 5a and 5b, and it is possible to eliminate various deteriorations in the control performance of the ultrasonic actuator.

The driving voltage applied to the piezoelectric element, which is a capacitive load, is a periodic signal having a constant frequency. Therefore, a digital IC operating with a 5V power supply or the like used in a general logic circuit is used to control the periodic signal.
Can be used, it is possible to reduce the size of the power supply, and it is possible to greatly expand the applicable range of the ultrasonic actuator.

However, in the driving device shown in FIG. 7, it is necessary to change the control signal to ± in order to reverse the driving direction of the ultrasonic actuator. Therefore, general digital IC
Difficult to use. Further, the driving device shown in FIG. 7 utilizes the characteristics of the respective unsaturated regions of the transistors 11, 12, 14, and 15. Therefore, switching control by a digital signal using a digital IC cannot be effectively performed.

[0012]

Therefore, the present applicant has
Previously, Japanese Patent Application No. 9-174396 proposed a capacitive load driving device that can be controlled by a switching signal of a digital IC.

FIG. 8 is an explanatory diagram showing the configuration of the driving device 17 according to this proposal. As shown in the figure, the driving device 17 has a first power supply + 30V and a second power supply -30V.
And first and second complementary types connected in series between
Switching elements TR1, TR2 and a third switching element TR for opening and closing the first switching element TR1.
3 and a fourth switching element TR4, which is complementary to the third switching element TR3 and opens and closes the second switching element TR2, at a connection point 23 between the first and second switching elements TR1, TR2. This is a capacitive load driving device for connecting a capacitive load. The third switching element TR3 includes a first power supply +30 V and a second power supply −3.
0V, and is connected to GND which is a reference for its own switching.
Has a potential between the first power supply +30 V and the second power supply −30 V, is connected to a third power supply +5 V that is a reference for its own switching, and has third and fourth switching elements TR3 and TR4. Are opened and closed complementarily by a switching signal having a signal level based on the potential of GND and the third power supply + 5V.

According to the driving device 17 according to this proposal,
Certainly, it is possible to supply a high-potential drive voltage to a capacitive load without using a step-up transformer for the output, and the control signal can be easily generated and controlled by a digital IC.

However, in the driving device 17 according to this proposal, the first power supply +30 V, the second power supply -30 V, and the third power supply
It is necessary to use three power supplies of +5 V and GND. Further, it is necessary to use a phase shifter for generating the two drive signals S1 and S2. Further, the switching element TR
1. During switching of TR2, in order to prevent both of them from turning on at the same time to prevent a transient through current from flowing,
It is also necessary to provide a delay circuit. For this reason, there is a problem that the size of the drive device body is inevitable, and the original feature of the ultrasonic actuator, which is small and light, is impaired due to the size of the drive device as an auxiliary device.

Here, an object of the present invention is to make it possible to supply a high-potential drive voltage to a capacitive load without using a step-up transformer for output, and to provide a control signal to a digital IC.
It is an object of the present invention to provide a capacitive load driving device which can be generated and controlled more easily and can be further downsized.

[0017]

According to the first aspect of the present invention, there is provided the following:
A first switching element and a second switching element, which are connected in series between a first power supply and a second power supply, and are connected in series between the first power supply and the second power supply; Two electronic elements that allow current to flow in one direction to each of the first switching element and the second switching element in accordance with a voltage applied to each of the first switching element and the second switching element. A driving device for a capacitive load, wherein a capacitive load is connected to a connection point of elements.

According to a second aspect of the present invention, there is provided a first switching element and a second switching element, which are connected in series between a first power supply and a second power supply, and are complementary to each other; Two electronic elements that are connected in series between the power supply and a current that flows a current in one direction to each of the first switching element and the second switching element according to a voltage applied to each of the first switching element and the second switching element And a third switching element and a fourth switching element, which are complementary to each other and are connected in series between the first power supply and the second power supply.
A capacitive load driving device, wherein a capacitive load is connected to a connection point of a switching element.

According to a third aspect of the present invention, in the capacitive load driving device according to the first or second aspect, both the first switching element and the fourth switching element are PNP transistors and the second switching element. And a third switching element are both NPN transistors, and two electronic elements are a first diode connected in parallel in a forward direction between a base and an emitter of a PNP transistor as a first switching element; A driving device for a capacitive load, comprising a second diode connected in parallel in a forward direction between a base and an emitter of an NPN transistor serving as a switching element.

According to a fourth aspect of the present invention, there is provided the first to third aspects.
In the capacitive load driving device described in any one of the above, a third diode and a fourth diode are respectively connected in series in a forward direction between the first diode and the second diode. A driving device for a capacitive load.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, an embodiment of a capacitive load driving device according to the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, an example in which the vibration actuator is an ultrasonic actuator that uses an ultrasonic vibration region will be described.

FIG. 1 is a perspective view showing a schematic configuration of the ultrasonic actuator 100. The ultrasonic actuator 100 according to the present embodiment includes a vibrator 101 and a relative motion member 102 that generates relative motion between the vibrator 101 and the vibrator 101.
Hereinafter, these components will be described separately.

[Vibrator 101] The vibrator 101 has an elastic body 103 and a piezoelectric body 104 mounted on one plane of the elastic body 103.

The elastic body 103 is made of SUS3 in this embodiment.
04 forms a rectangular flat plate. Also, the elastic body 10
The dimensions of each part 3 are set such that the natural frequencies of the first-order longitudinal vibration L1 and the fourth-order bending vibration B4 generated in the vibrator 101 substantially match each other. The elastic body 103
May be formed of a metal material having a large resonance sharpness, such as steel, phosphor bronze, or an elinvar material, other than stainless steel.

On one flat surface of the elastic body 103, a piezoelectric body 104 to be described later is mounted, for example, by bonding. Further, two grooves in the width direction of the elastic body 103 are provided on the other plane of the elastic body 103 in the relative movement direction (the left-right direction in FIG. 1).
Are provided at a predetermined distance from each other. Sliding members having a rectangular cross-sectional shape are fitted into these grooves, respectively, adhered with an epoxy-based adhesive, and mounted in a protruding manner. The two sliding members are provided at positions corresponding to two antinode positions located outside of the four antinode positions of the fourth-order bending vibration generated in the elastic body 103.

These sliding members are used as driving force take-out portions 1.
Functions as 05a and 105b. Therefore, the elastic body 103 is provided with the driving force extracting portion 105 made of these sliding members.
a, and contacts the relative motion member 102 via 105b.

In this embodiment, 15% by weight of glass fiber and 5%
A material mixed with molybdenum disulfide by weight (trade name:
Polyflon, Daikin Industries, Ltd.). The driving force extracting portions 105a and 105b do not need to be located exactly at the antinode position of the bending vibration B4, and may be near this antinode position.

In this embodiment, the piezoelectric body 104 is made of PZT.
(Lead titanium zirconate, registered trademark). This piezoelectric body 104 has input areas 104a and 104c to which an A-phase drive signal is input.
Then, input regions 104b and 104d are formed in which the B phase whose phase is different from the A phase by (π / 2) is input. Each of the input areas 104a to 104d is formed in four areas defined by five nodal positions of bending vibration generated in the elastic body 103. That is, since each of the input areas 104a to 104d that are deformed by the input of the drive signal does not straddle any of the five joint positions that are fixed points, the input area 1
The deformation of 04a to 104d is not suppressed by each node position. Therefore, each of the input areas 104a to 104d
Is input to the elastic body 10 at the maximum efficiency.
3 is converted into mechanical energy.

[0029] Of the five nodal positions of the bending vibration, two nodal positions respectively located second from both ends include:
Detection regions 104p and 104p ′ for outputting electric energy by the longitudinal vibration generated by the vibrator 101 are provided in a semicircular shape. Thereby, the vibration state of the longitudinal vibration generated by the vibrator 101 is detected.

The input regions 104a to 104d and the detection regions 104p and 104p 'have their respective surfaces covered with silver electrodes 106a to 106d, 106p and 106p'. As a result, a drive signal is input independently to each of the input areas 104a to 104d, or each of the detection areas 104p,
A detection signal can be output independently from 104p '.

In this embodiment, the vibrator 101 is formed so as to be point-symmetric about the center of the plane of the vibrator 101. As a result, the driving force extraction units 105a, 105
The elliptical motion generated at 05b can be made to have substantially the same shape, and a drive difference (left-right difference) due to reversal of the relative motion direction hardly occurs.

As shown in FIG. 1, a relative motion member 102 is disposed in contact with the bottom surfaces of the driving force extracting portions 105a and 105b of the vibrator 101. In this embodiment, the relative movement member 102 is formed of stainless steel in a flat plate shape, and is movably supported in a relative movement direction (longitudinal direction of the vibrator 101 in FIG. 1) by appropriate means. The relative motion member 102 may be made of a copper alloy, an aluminum alloy, a polymer material, or the like.

In this manner, the first-order longitudinal vibrations and the four-dimensional vibrations generated in the input areas 104a and 104c of the piezoelectric body 104 are generated.
A drive signal of the A phase having a frequency substantially corresponding to the natural frequency of each of the next bending vibrations is input, and a B phase having a phase difference of (π / 2) from the A phase is input to the input regions 104b and 104d. Is input. Then, the first-order longitudinal vibration and the fourth-order bending vibration are simultaneously generated in the elastic body 103. These vibrations are combined to generate an elliptical motion in the driving force output units 105a and 105b. Thereby, the relative motion member 102 generates a relative motion with the vibrator 101 in the relative motion direction.

The driving device 20 for generating a driving voltage to be applied to the two groups of input areas 104a, 104c and 104b, 104d of the ultrasonic actuator 1 will be described. FIG. 2 is an explanatory diagram showing a configuration in a case where the driving device of the present embodiment is applied to the driving device 20 of the ultrasonic actuator 100.

The driving device 20 includes an oscillation circuit 21 for regulating the frequency of the driving voltage, two groups of piezoelectric elements 104a,
A phase shift circuit 22 that generates a different phase signal to apply signals having phases (π / 2) different from each other to 04c, 104b, and 104d, and drive circuits 23A and 23B using semiconductor elements are provided. .

The signal having a constant frequency generated by the oscillation circuit 21 is converted into two signals having phases different by (π / 2) by the phase shift circuit 22. These signals are directly input to the drive circuits 23A and 23B, respectively. The drive circuits 23A and 23B operate the internal semiconductor elements based on the input signals, and thereby have a maximum value of about ± 30V.
A drive voltage having a value of

FIG. 3 is a timing chart for explaining how the oscillation circuit 21 and the phase shift circuit 22 generate two signals having different phases (π / 2). Oscillation circuit 21
Is output from the phase shifter 2
2, two D-type flip-flops 24, 2
5 is input as a clock signal. The two D-type flip-flops 24 and 25 are connected so that their outputs Q and NQ and the data input terminal D are connected to each other.
It is configured to generate a signal of Q2. That is, the signals Q1 and Q2 constitute one cycle of four clocks, and the signals Q1 and Q2 are shifted by exactly 1/4 cycle, that is, the phase shift is (π / 2). The signal Q1 is the driving circuit 2
3A, and the signal Q2 is input to the drive circuit 23B via the exclusive OR gate 26.

FIG. 4 is a principle diagram of the driving circuit 23A.
Since the driving circuit 23B has the same configuration, the following description will be made by taking the driving circuit 23A as an example. As shown in FIG. 4, the drive circuit 23A of the present embodiment includes complementary first switching devices connected in series between (i) a first power supply +30 V and (ii) a second power supply −30 V. A PNP transistor TR1 as an element and an NPN transistor TR2 as a second switching element, and (iii) connected in series between a first power supply + 30V and a second power supply -30V, and are connected to the PNP transistor TR1 and the NPN transistor TR2, respectively. Depending on the applied voltage, PN
P transistor TR1 and NPN transistor TR2
Diodes D1 and D2, which are two electronic elements that allow current to flow in one direction, respectively, are provided.

The emitter terminal of the PNP transistor TR1 is connected to the first power source + 30V, and the emitter terminal of the NPN transistor TR2 is connected to the second power source -30V.
PNP transistor TR1, NPN transistor T
The collector terminals of R2 are connected to each other. These transistors TR1 and TR2 are complementary.

The flip-flops and gates used in the phase shift circuit 22 are digital ICs operated by a +5 V power supply used in general logic circuits, and are, for example, T
It is a TL or CMOS device.

An ultrasonic actuator 100 which is a capacitive load is connected to a connection point 27 between the PNP transistor TR1 and the NPN transistor TR2. And the piezoelectric body 1
The A-phase drive signal is input to the input areas 104a and 104c of the input terminal 04.

The drive circuit 23A of the present embodiment is connected in parallel in the forward direction between the first diode D1 between the base and the emitter of the PNP transistor TR1 and in parallel between the base and the emitter of the NPN transistor TR2. And the second diode D2 are connected in series. These diodes D1 and D2 are connected to the transistor T
When switching between R1 and TR2, a through current that turns on both R1 and TR2 is reliably prevented from flowing.

A third diode D3 and a fourth diode D4 are connected in series in the forward direction between the first diode D1 and the second diode D2. By these diodes D3 and D4, responsiveness to a pulse signal input from the phase shift circuit 22 is improved.

The PNP transistor TR1 and the NPN transistor TR2 have resistors R1 and R2, respectively.
, The input signal from the phase shift circuit 22 is input.
In the present embodiment, the drive circuit 23A is configured as described above.

Next, the operation of the driving circuit 23A will be described. When the potential from the phase shift circuit 22 changes in the + direction at the terminal 28, a base current defined by the resistor R2 flows between the base and the emitter of the NPN transistor TR2, and the NPN transistor TR2 is turned on, and the connection point 27
Is supplied with a voltage of about -30V.

At this time, a reverse voltage is applied between the base and the emitter of the PNP transistor TR1, and no base current flows through the PNP transistor TR1, so that the PNP transistor TR1 remains off.

On the other hand, at the terminal 28, when the potential from the phase shift circuit 22 changes in the negative direction, the PNP transistor T
A base current defined by the resistor R1 flows between the base and the emitter of R1, the PNP transistor TR1 turns on, and a voltage of about +30 V is supplied to the connection point 27.

At this time, a reverse voltage is applied to the base and the emitter of the NPN transistor TR2, and no base current flows through the NPN transistor TR2, so that the NPN transistor TR2 remains off. In this way,
The drive circuit 23A shown in FIG.
The supply of a high drive voltage switched at V is performed.

In the above description, the PNP transistor TR
1 is on, the NPN transistor TR2 is off, and when the PNP transistor TR1 is off, NP
The N transistor TR2 is on. Further, at the time of switching, the third diode D3 and the fourth diode D4 make it difficult for the PNP transistor TR1 and the NPN transistor TR2 to saturate, thereby improving responsiveness. Therefore, in the drive circuit 23A shown in FIG. 4, it is not necessary to provide a delay circuit for preventing a through current.

The switching drive voltage of about ± 30 V thus generated is supplied from the drive circuit 30A as an A-phase signal to the ultrasonic actuator 10 in FIG.
0 are input to a group of input areas 104a and 104c, while the drive circuit 30B inputs the group of input areas 104b and 104d as a B-phase signal to the ultrasonic actuator 100.

The symbol P in FIG. 2 is a signal supplied from a control circuit (not shown). The driving direction of the ultrasonic actuator 100 is set to the right or left (for a rotary ultrasonic actuator, the right rotation Left rotation or).

As described above, according to the present embodiment, it is possible to provide the driving device 20 which has two power supplies and does not require a delay circuit. Therefore, it is possible to supply a high-potential drive voltage to a capacitive load without using a step-up transformer for output, and the control signal can be easily generated and controlled by a digital IC. Further, the size can be significantly reduced.

(Second Embodiment) Next, a second embodiment will be described. FIG. 5 is a principle diagram of the driving circuit 23A-1 according to the second embodiment. In the description of FIG. 5, portions different from FIG. 4 described above will be described, and the common portions will be denoted by the same reference numerals in the drawings, and redundant description will be omitted.

In this embodiment, the configuration of the driving circuit 23A-1 is different from that of the driving circuit 23A shown in FIG. That is,
In the drive circuit 23A-1, a resistor R3 and an NPN transistor TR3 and a PNP transistor TR4 arranged in series are added in parallel between the terminal 27 and the PNP transistor TR1 and the NPN transistor TR2.

In drive circuit 23A-1, NPN transistor TR3 and PNP transistor TR4 operate as an emitter follower and operate as a current amplifier. Therefore, according to the driving circuit 23A-1, the capacity of the output current is increased.

[Modification] In the above description of the embodiment,
Although the case where a bipolar transistor of a PNP transistor and an NPN transistor is used has been described as an example, the driving device according to the present invention is not limited to such a form. These bipolar transistors can be replaced with FET transistors, IGBTs, and other switching elements.

Although the TTL or CMOS level digital IC operating at +5 V has been described as a circuit for controlling the switching signal, the driving device according to the present invention is not limited to such an embodiment. The present invention can also be applied to a digital IC operating at +3 V or a digital IC operating at another power source. Further, the control may be performed by a microprocessor, a gate array, or another LSI.

Although the description has been given of the case where the drive voltage is ± 30 V, the drive voltage is not limited to this value. Although it depends on the withstand voltage of the transistor or the like to be used, the present invention can be applied to a driving voltage of ± several hundreds of volts, and conversely, can be applied to a driving voltage of ± 30 volts or less. Further, the drive voltage does not necessarily have to have a plus / minus symmetrical value, and a power supply having different values on the plus side and the minus side may be used.

Although the case where the vibration actuator is an ultrasonic actuator has been described as an example, the present invention is equally applicable to an ultrasonic actuator in a vibration region other than the ultrasonic wave. Further, the vibration actuator performing linear relative motion has been described as an example, but the present invention can be similarly applied to a rotary vibration actuator.

Further, a piezoelectric body is used as an element for performing mutual conversion between electric energy and mechanical energy. However, the present invention is not limited to this. For example, another electromechanical conversion element such as an electrostrictive element or a magnetostrictive element may be used. It can also be used.

[0061]

As described in detail above, claims 1 to 5
According to the fourth aspect of the present invention, it is possible to supply a high-potential drive voltage to a capacitive load without using a step-up transformer for output, and it is possible to easily generate and control a control signal by a digital IC, and further remarkably. A capacitive load driving device that can be reduced in size can be provided. In particular, according to the invention of claim 2, the capacity of the output current can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of an ultrasonic actuator according to a first embodiment.

FIG. 2 is an explanatory diagram showing a configuration in a case where the driving device of the first embodiment is applied to a driving device of an ultrasonic actuator.

FIG. 3 is a timing chart illustrating how two signals having different phases (π / 2) are generated in the oscillation circuit and the phase shift circuit in the first embodiment.

FIG. 4 is a principle diagram of a drive circuit according to the first embodiment.

FIG. 5 is a principle diagram of a drive circuit according to a second embodiment.

FIG. 6 is a block diagram illustrating a configuration of a driving device using a step-up transformer.

FIG. 7 is an explanatory diagram of a driving device proposed in Japanese Patent Application Laid-Open No. 9-9650.

FIG. 8 is an explanatory diagram showing a configuration of a driving device proposed in Japanese Patent Application No. 9-174396.

[Explanation of symbols]

 + 30V First power supply -30V Second power supply TR1 First switching element (PNP transistor) TR2 Second switching element (NPN transistor) TR3 Third switching element (NPN transistor) TR4 Fourth switching element (PNP transistor) D1, D2 , D3, D4 Diode 23A Driver 27 Connection point

Claims (4)

[Claims] A first switching element and a second switching element, which are connected in series between a first power supply and a second power supply, and are complementary to each other; and between the first power supply and the second power supply. And two electronic elements that flow a current in one direction to each of the first switching element and the second switching element according to a voltage applied to each of the first switching element and the second switching element. A capacitive load driving device, comprising: connecting a capacitive load to a connection point between the first switching element and the second switching element. 2. A first switching element and a second switching element which are connected in series between a first power supply and a second power supply, and which are complementary to each other, between the first power supply and the second power supply. Two electronic elements, which are connected in series to each other and flow a current in one direction to each of the first switching element and the second switching element according to a voltage applied to each of the first switching element and the second switching element; A third switching element and a fourth switching element, which are complementary to each other and are connected in series between the first power supply and the second power supply; and a capacitance is provided at a connection point between the third switching element and the fourth switching element. A driving device for a capacitive load, characterized by connecting a capacitive load. 3. The driving apparatus for a capacitive load according to claim 1, wherein the first switching element and the fourth switching element are PNP transistors, and the second switching element and the third switching element are a third switching element and a third switching element. The switching elements are both NPN transistors, and the two electronic elements are the PN which is the first switching element.
A first diode connected in parallel between the base and the emitter of the P transistor in the forward direction, and a second diode connected in the forward direction between the base and the emitter of the NPN transistor, which is the second switching element. A driving device for a capacitive load, comprising: 4. One of claims 1 to 3
In the capacitive load driving device described in the paragraph, between the first diode and the second diode, a third diode and a fourth diode are connected in series in a forward direction, respectively. Characteristic capacitive load drive.