JPS62114482A - Displacement operating circuit - Google Patents

Abstract

PURPOSE:To save power by conducting charging to a piezoelectric element from a power supply and recovery to the power supply from the piezoelectric element through an inductor. CONSTITUTION:An inductor 18 is separated left and right at a midpoint 19, one end of the inductor 18 is connected to a power supply 20 through a diode D1 for a switching element, and the other end is connected to a common potential point COM through a diode D2 for the switching element and a piezoelectric element 21. Switches S5, S6 consisting of field-effect transistors are fitted at both ends of the diodes D1, D2, and the switching of the switches is controlled by operating signals Sm. The application of power supply to the piezoelectric element 21 and recovery to the power supply 20 of charges charged in the piezoelectric element 21 are performed through the inductor 18 on the drive and control of the titled circuit. Accordingly, the power of the displacement operating circuit can be conserved.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a displacement operation circuit that fully operates minute displacements.
In particular, the field using piezoelectric elements relates to rectangular displacement operating circuits.

<Prior art> The original position control device and circuit using piezoelectric elements are
This is shown in FIG. 5 and will be explained.

In FIG. 4, reference numeral 10 denotes a fixing table, on which rectangular piezoelectric elements o and 12 are fixed at appropriate intervals. The piezoelectric elements 11, 12 have lead wires t1. t2 and 13.14 are fixed. A stepped frame 13.14 having a tip connected thereto is fixed to the side surface of the piezoelectric element 11.12. Near the tip, a nozzle 15 is arranged facing the frame I4 and outputting a single layer of air.

By applying a voltage between the lead wires tr and 12 or between the lead wires 13 and 14, the piezoelectric element 11 or 1
2 expands and contracts as shown by arrows d, d2. Along with this, the tips 16 of the frames 13 and 14 are displaced as shown by the arrow d3, and due to this displacement d3, the distance between the tips of the nozzles 15 and the frame 14 changes, and the nozzle back pressure changes. This change in back pressure is utilized as part of the structure of, for example, an electropneumatic positioner.

By the way, the electric circuit for operating the piezoelectric elements 11 and 12 of this displacement operation circuit is configured as shown in FIG. 5, for example.

The piezoelectric element 11 includes a lead wire 11, a resistor, and a switch S1.
, the DC power supply 17 and the lead wire 12 are connected in series to be charged, and the lead wires t1,
The resistance ratio 1, the switch S2, and the lead wire t2 are each connected in series and configured to be discharged. The piezoelectric element 12 is configured such that the lead wire 13, the DC power supply 17, the switch S3, the resistor R2, and the lead wire t4 are connected in series to be charged, and the lead wire 13,
The switch S4, the resistance ratio 2, and the lead wire t4 are each connected in series and configured to be discharged.

By making the switch S, the capacitance between the electrodes of the piezoelectric element 11 is charged through the resistor R1, so that the voltage between the electrodes increases. By closing switch S2, discharge occurs through the resistor. The piezoelectric element 12 is also charged by making the switch S3, and the piezoelectric element 12 is also charged by making the switch S3.
Discharge occurs due to the make-up.

Therefore, the voltage between the electrodes of the piezoelectric elements 11 and 12 is controlled by changing the on/off duty cycle of the switch 81 vs. S2 or the switch 83 vs. S4.
This allows the displacement d3 to be controlled.

<Problems to be solved by the invention> However, such a displacement operation circuit does not require the switch sl,
S26 or switch 83. Due to the outflow of current from the DC power supply due to the switching operation of s4, the resistance ratio is 1. R
There is a problem that the power loss in 2 becomes large.

Means for Solving the Problems> In order to solve the above problems, the present invention provides an inductor, a first switch means for applying a power supply voltage to the inductor, and an inductor connected in parallel to the first switch means. a piezoelectric element that receives the current flowing out from the inductor; a third switch means that causes the current flowing out of the inductor to flow into the piezoelectric element; and a fourth switch means for applying voltage, and the piezoelectric element is changed by repeating alternate conduction of the first switch means and the third switch means! ! The element is charged, and the discharge 'R current from the piezoelectric element is recovered from the piezoelectric element to the power source by repeating the alternating conduction of the fourth switch means and the second switch means.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

18 is an inductor, which is separated into left and right inductors 18a and 18b by a midpoint 19. Inductor 1
One end of 8a is a diode D that functions as a switch element.
1, and its cathode is connected to the positive electrode of a power supply 2o. The negative voltage of the power supply 20 is the inductor 18
It is connected to the common potential point 00M together with the midpoint 19 of .

One end of the inductor 18b is connected to the anode of a diode D2 functioning as a switching element, and its cathode is connected to the common potential point COM via the piezoelectric element 21.

A drain D and a source S of a field effect transistor are connected to both ends of the diode D1, and a resistor FLG1 is connected between the gate G and the source S to constitute a switch S5. Further, the drain and source S of a field effect transistor are connected to both ends of the diode D2, and the resistance ratio between the gate and source S is connected. 2 are connected to constitute a switch S6. Switch 55JS6 is the operation signal Sml
' Its opening/closing is controlled by Sm2.

Next, the operation of the circuit shown in FIG. 1 will be explained using the waveform diagram shown in FIG. 2.

When the switch S5 is turned on by the operation signal Sm1 (FIG. 2(a)), the positive voltage of the power source 2o is applied to the inductor 18a via the switch S5. At this time, the terminal of the inductor 18b becomes a negative voltage, and the diode D2 is turned off. The switch S6 is off because it is not operated as shown in Fig. 2 (b), and the inductor 183Kl': An increasing current 11 flows as shown in period t1.

Next, when the switch S5 is turned off (FIG. 2 (a)), the current holding characteristics of the inductors 18a and 18b make the terminal of the inductor 18b a positive voltage, and the piezoelectric element 21 is charged via the diode D2. do. At this time, a reverse voltage is applied to the diode D1, and the diode D1 is turned off. The charge 91 current i which charges the piezoelectric element 21 appears in the period t2 shown in FIG. 2). As a result of this operation, the potential of the piezoelectric element 21 is slightly increased as shown in FIG. 2 (E). The voltage e across the piezoelectric element 210 gradually increases each time the operation signal Sm1 arrives.

When the switch 86 is turned on by the operation signal S (second
In the figure, the electric charge charged in the piezoelectric element 21 is discharged to the inductor 18b via the switch S6 and the inductor 18. This is indicated by period t3 in FIG. 2). At this time, the open end of the inductor 18a becomes a negative voltage, the diode D1 is turned off, and the switch S5 is turned off (second
Figure (a)).

Next, when the switch S6 is turned off (Fig. 2, 10), due to the current holding characteristics of the inductors 18a and 18b, the open end of the inductor 18a becomes a positive voltage, and the open end of the inductor 18b becomes a negative voltage, as shown in Fig. 2. Current 11 during period t4 of 9
is collected by the power source 20. Every time the operation signal Sm2 arrives, the electric charge stored in the piezoelectric element 21 is discharged and collected by the power source 20.

FIG. 3 is a circuit diagram showing another embodiment of the present invention. This embodiment shows the case where two of the embodiments shown in FIG. 1 are used. If two piezoelectric elements are used, for example, as shown in FIG. 4, there is an advantage that the influence of temperature can be reduced. Regarding Fig. 3, when compared with Fig. 1, the operation signal "m
l to Sm3, operation signal Sm2 to Sm4, switch S
5 to S7, switch S6 to S8, reactor 18 (
18a, 18b) is 22 (22a.

22b), diode D1 to D3, diode D2
is connected to D4, the piezoelectric element 21 is connected to 23, and the resistor ``Gl'' is connected to FLG.
3, the resistors 1to2 correspond to R64, and their operations are similar to those shown in FIGS. 1 and 2.

Note that the diode DD is the switch 85-1"
2. A switching function may be provided using a transistor like S8.

<Effects of the Invention> As specifically explained above in conjunction with the embodiments, the present invention has the following advantages: (a) Since the piezoelectric element is charged from the power source via the inductor, the conventional resistor Rt shown in FIG. , R2
It is possible to limit the charging current to the piezoelectric element without the power loss that is consumed in is completed, and furthermore, (b), the charge to the pressure'IJl element? Since the current charging α is carried out through the inductor, there is no need to charge at a high voltage of, for example, 100μ, unlike the voltage of the conventional α source 17 shown in FIG. The piezoelectric element can be charged with a low-voltage power source 20 such as 20, and in addition (c), since the electric charge of the piezoelectric element is discharged via an inductor, the voltage '1! Voltage of element 21 0.5V
It has advantages such as being able to discharge at a high voltage such as 6 from IF+NO to recover power.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a waveform diagram showing waveforms of each part shown in FIG. 4 is a block diagram showing the overall configuration of a conventional displacement operating device, and FIG. 5 is a circuit diagram showing an example of a displacement operating circuit of the displacement operating device of FIG. 4. 11, 12, 21, 23... Piezoelectric element, 17.20・
...Power supply, 18゜22...Reactor, S ~ S...
Switch, sml to sm4...operation signal, D1 to D
4...Diode. Figure 3 Figure 4

Claims (1)

[Claims] an inductor, a first switch means for applying a voltage of a power source to the inductor, and a first switch means connected in parallel with the first switch means for allowing a current flowing out of the inductor to flow into the power source and blocking a current flowing out from the power source. 2 switch means, a piezoelectric element that causes displacement by voltage application by the inductor, a third switch means that causes an outflow current from the inductor to flow into the piezoelectric element, and a piezoelectric element that is connected in parallel to the third switch means. a fourth switch means for applying an inter-electrode voltage of A displacement operation circuit that recovers discharge current from the piezoelectric element to the power source by repeating alternate conduction of the second switch means.