JP3130371B2 - Piezoelectric transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transformer, and more particularly, to a piezoelectric transformer having three types of ports.

[0002]

2. Description of the Related Art Conventionally, an electromagnetic transformer is usually used as a power supply. However, a piezoelectric transformer has attracted attention as a small, lightweight, and solid-state device. Such piezoelectric transformers are used in various fields, and it is expected that the fields of use will be further expanded in the future.

[0003] A conventional form or method of using such a piezoelectric transformer will be described with reference to FIG. That is, FIG. 6A is a block diagram showing a general DC input drive circuit configuration in a case where an oscillation drive signal is obtained using a conventional piezoelectric transformer. A predetermined frequency f0 is oscillated from a generally known oscillation circuit 2 including an oscillation circuit, a crystal oscillation circuit, and the like, and the frequency f0 is set to the oscillation circuit 2
And switches the switching circuit 3 on / off at the predetermined frequency f0.
F, an output signal of a predetermined frequency is input to the piezoelectric transformer 1, and a predetermined drive signal output is obtained from the piezoelectric transformer based on the input signal.

FIG. 6B shows an equivalent circuit having such a configuration. That is, in the related art, when it is intended to obtain a drive signal using the piezoelectric transformer 1, the piezoelectric transformer 1 and the oscillating means 2 for generating the reference frequency are always used as a pair. Therefore, the driving of the piezoelectric transformer uses an oscillation circuit provided separately from the piezoelectric transformer, as in the case of using the electromagnetic transformer.

Therefore, since the piezoelectric transformer is used in a resonance state like a filter and a vibrator, the driving circuit needs to oscillate at the resonance frequency f0 of the transformer. Therefore, a conventional piezoelectric transformer driving circuit, that is, an oscillation circuit is composed of L, C, or a switching element, and the like.
Of course, it is necessary to set circuit constants so as to oscillate at the resonance frequency f0. Therefore, in order to stably oscillate the oscillation circuit, use the same material and material as the piezoelectric transformer to form the oscillation circuit. It is necessary to create the circuit using a vibrator that oscillates in the same vibration mode, which complicates the manufacturing process,
There is a problem that the manufacturing cost is significantly increased because the operation becomes complicated and the number of components increases.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, simplify the drive circuit, shorten the manufacturing process, and reduce the number of components. While significantly reducing production costs,
Since a stable reference frequency suitable for the piezoelectric transformer can be obtained, a piezoelectric transformer having stable characteristics is provided.

[0007]

The present invention employs the following technical structure to achieve the above object. That is, it is a piezoelectric transformer having three types of ports. More specifically, at least one port is connected to reference frequency generating means for setting the frequency of an input signal to the piezoelectric transformer. Is a piezoelectric transformer in which the reference frequency generating means itself is provided in the piezoelectric transformer.

[0008]

According to the present invention, the above-described configuration is employed. The basic feature of the present invention is that, in the piezoelectric transformer, a vibrator for generating a reference frequency which is a reference of an oscillation circuit is provided. Since it is built inside the piezoelectric transformer, the configuration of the oscillation circuit itself can be made of the same material as the main constituent material of the piezoelectric transformer, which simplifies the manufacturing process and has stable characteristics. A reference frequency generation circuit can be configured.

Further, an oscillation circuit provided separately from the piezoelectric transformer simply receives a reference frequency from the reference frequency generating circuit built in the piezoelectric transformer and receives a driving signal having a predetermined frequency. Since it is only necessary to generate a signal, starting with the oscillation circuit,
Since many circuits and parts are not required, the circuit configuration is simplified, thereby stabilizing and homogenizing the circuit characteristics, improving the commercial value, simplifying the manufacturing process, and reducing the number of components. The reduction enables a significant reduction in production costs.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. First, FIG. 1A is a block diagram showing an example of the configuration of a DC drive circuit using the piezoelectric transformer according to the present invention, and FIG. 1B is an example of the configuration of the piezoelectric transformer according to the present invention. FIG.

In FIG. 1B, three types P1, P2 and P3
A piezoelectric transformer 1 having a port indicated by P is shown, and among the port groups denoted by P1, P2, and P3,
In order for at least one port P3 to set the frequency of an input signal to the piezoelectric transformer 1, reference frequency generating means (vibrator) 4 provided in the piezoelectric transformer 1
Is connected to

Therefore, the piezoelectric transformer 1 according to the present invention has
It has an input port P1, an output port P2, and a reference frequency generating port P3. FIG. 1 (A) is a diagram showing a structure of a D configured using the piezoelectric transformer 1 according to the present invention.
5 is a block diagram of a C drive circuit, in which an input port P1 of the piezoelectric transformer 1 is connected to an appropriate switching circuit 3 and a DC power input unit, and an output port P2 is not shown; It is connected to an AC drive circuit.

On the other hand, the reference frequency generating port P3 of the piezoelectric transformer 1 according to the present invention is connected to an oscillation circuit 2 provided separately from the piezoelectric transformer 1, and the oscillation circuit 2 , The output of the switching circuit 3
The switching circuit 3 is driven by the output signal of the oscillation circuit 2 and the piezoelectric transformer 1
Is configured to be driven.

That is, the piezoelectric transformer 1 according to the present invention comprises:
Since the oscillation circuit 4 for generating the reference frequency, that is, the vibrator is built in the piezoelectric transformer 1,
The oscillation circuit for generating the reference frequency can be manufactured mainly by using the same material as the main constituent material of the piezoelectric transformer 1. For example, when the piezoelectric transformer is made of ceramic, crystal, lithium niobate (lithium niobate), lithium tantalate (lithium tantalate), or the like, an oscillation circuit for generating a reference frequency should be made of the same material. Can be done.

Further, the oscillation circuit for generating a reference frequency according to the present invention may be a reference clock in the driving circuit. Further, the other oscillation circuit 2 shown in FIG.
It is not necessary to include an oscillation circuit for generating a reference frequency, and for example, it may be constituted by a simple frequency dividing circuit or a modulation circuit.

FIG. 2 shows a specific example of the piezoelectric transformer according to the present invention. FIG. 2A is a perspective view showing an example of the configuration of the piezoelectric transformer 1 according to the present invention, and FIG.
FIG. 3 is a diagram illustrating an example of a configuration of a drive circuit configured using the above-described piezoelectric transformer 1. In FIG. 2 (A),
One of the electrode pairs of the input port P1, the output port P2, and the reference frequency generating port P3 is arranged on one main surface S1 side of the piezoelectric transformer 1, and the other electrode pair is arranged on the piezoelectric transformer 1 side. Is arranged on the other main surface S2 side.

That is, in the present embodiment, the arrangement of the ports is such that the same pattern is formed on the front and back surfaces of the piezoelectric transformer. In such an arrangement pattern, the vibration direction of the piezoelectric transformer 1 is a direction indicated by an arrow XX ′ in the figure. Further, in FIG. 2B, a piezoelectric transformer 1, an oscillation circuit 2,
And a switching circuit 3, and the connection form is the same as the block diagram of FIG.

In this embodiment, the output from the output port P2 of the piezoelectric transformer 1 may be connected to an appropriate rectifier circuit depending on the application. In addition, if the example of the dimension in the piezoelectric transformer according to the present invention is shown, for example, the thickness of the piezoelectric transformer changes with the frequency,
For example, 0.2 to 0.5 mm, 1 mm in width and 15 to 20 mm in length.

FIG. 3 is a perspective view showing the configuration of another specific example of the piezoelectric transformer according to the present invention. FIG. 3 (A) shows the configuration of a piezoelectric transformer utilizing width sliding vibration. FIG. 3 (B) shows a typical vibration form of the width-slip vibration. FIG. 3 (B) is a plan view of the piezoelectric transformer 1, and the vibration direction is opposite at both ends and the center in the width direction. This shows a special vibration mode.

In order to realize such a special vibration mode, in the piezoelectric transformer according to the present invention, as shown in FIG.
Two electrodes d11 and d12 corresponding to the input port P1 are arranged on one main surface S1 of the piezoelectric transformer in parallel with the longitudinal direction of the piezoelectric transformer, and two electrodes d21 and d22 corresponding to the output port P2 are connected to the two electrodes d21 and d22. The piezoelectric transformers are arranged in parallel with the longitudinal direction, and four electrodes d31 and d32 corresponding to the reference frequency generating port P3 are connected to d3.
3, d34 with the electrodes d11, d12 and electrode d21,
It is arranged corresponding to d22.

Such a width-slip vibration has a large electromechanical coupling coefficient. In particular, when the material forming the piezoelectric transformer uses lithium niobate (LiNbO3), the coefficient is as much as 62% depending on the crystal orientation. can get. The use of such width-slip vibration has advantages in that, in particular, in an energy trapping type piezoelectric transformer, it is possible to reduce the size, and furthermore, it is difficult for spurious to ride because the sound speed is low.

When such a configuration is adopted, the electrode pattern may be formed on only one side of the piezoelectric plate, and there is a possibility that the manufacturing process can be simplified. FIG. 4 is a view for explaining the configuration of another specific example of the piezoelectric transformer 1 according to the present invention, and shows the configuration of a piezoelectric transformer that generates a width-slip vibration different from the above-described width-swing vibration. .

The difference from the configuration of the piezoelectric transformer shown in FIG.
A reference frequency generating port P3 is arranged on one main surface S2 of the piezoelectric transformer, and the other port, ie, the input port P1
And the output port P2 are connected to the other main surface S of the piezoelectric transformer.
1. In such a specific example, although the simplification of the process cannot be expected, the physical advantage of width-slip vibration can be applied, and the reference frequency generating port P3 connected to the vibrator electrode is formed on the back surface. Because
Miniaturization is possible.

FIG. 5 shows another example of the structure of the piezoelectric transformer according to the present invention. That is, FIG. 5 shows an example of the configuration of a periodic drive type piezoelectric transformer.
It is configured to be driven by.

As can be seen from FIG. 5, in this specific example,
The electrodes d11 to d14 connected to the input port P1 are arranged in parallel or alternately with each other, and the electrodes d21 to d24 connected to the output port P2 are also arranged in parallel or alternately with each other. ing. Note that a common electrode d44 for the input port and the output port is provided at an intermediate portion between both electrode groups.

On the other hand, the respective electrodes d31 to d39 constituting the reference frequency generating port P3 are arranged corresponding to the respective electrodes. In the drawing, the waveform shown at the left end is a waveform showing the distribution of distortion. In this specific example, the reference frequency generating port P3, that is, the logarithm of the electrodes of the vibrator portion is configured to be equal to the sum of the logarithms of the electrodes corresponding to the input port P1 and the output port P3. Is what it is.

In this specific example, since the periodic drive type piezoelectric transformer is formed, there is an advantage that the series resistance at the time of resonance is smaller than that of the single electrode type piezoelectric transformer, and therefore, the power that can be handled becomes larger. .

[0028]

Since the piezoelectric transformer according to the present invention has the above-described structure, the manufacturing process can be simplified and a reference frequency generating circuit having stable characteristics can be formed. Further, the circuit configuration of the piezoelectric transformer is simplified and the characteristics of the circuit are stabilized and homogenized, thereby improving the commercial value and simplifying the manufacturing process.
By reducing the number of components, the production cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of one specific example of a piezoelectric transformer according to the present invention.

FIG. 2 is a diagram showing a configuration of another specific example of the piezoelectric transformer according to the present invention.

FIG. 3 is a diagram showing a configuration of still another specific example of the piezoelectric transformer according to the present invention.

FIG. 4 is a diagram showing a configuration of another specific example of the piezoelectric transformer according to the present invention.

FIG. 5 is a diagram showing a configuration of still another specific example of the piezoelectric transformer according to the present invention.

FIG. 6 is a diagram showing a configuration example of a conventional piezoelectric transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1: Piezoelectric transformer 2: Oscillation circuit 3: Switching circuit 4: Oscillation circuit for generating reference frequency P1: Input port P2: Output port P3: Port for generating reference frequency

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Noboru Wakatsuki 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Umeo Oshio 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Inventor Motoma Hiraki 1015 Ueodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 41/107

Claims (7)

(57) [Claims] 1. A have a three-port, of the port less
At least one is the frequency of the input signal to the piezoelectric transformer.
Connected to the reference frequency generating means for setting the number
The reference frequency generating means is provided in the piezoelectric transformer.
A piezoelectric transformer. Wherein the input port, according to claim 1, characterized in that comprises an output port and a port for a reference frequency generator
Of the piezoelectric transformer. 3. The apparatus according to claim 1 , wherein said reference frequency generating means is connected to said oscillating means provided separately from said piezoelectric transformer via said reference frequency generating port.
Or the piezoelectric transformer according to 2 . Wherein said reference frequency generating means provided in the piezoelectric transformer, one of the claims 1 to 3, characterized in that is composed mainly of the same material as the material constituting the piezoelectric transformer The piezoelectric transformer according to claim 1 . 5. The piezoelectric transformer comprises a periodic drive type piezoelectric transformer. In the piezoelectric transformer, the number of electrodes used for setting the frequency is determined by each electrode constituting an input port and an output port. The piezoelectric transformer according to any one of claims 1 to 4, wherein the sum is set so as to be the sum of logarithms. 6. In the piezoelectric transformer, any one of claims piezoelectric transformer according to claim 1, wherein it is intended to use a wide sliding vibration as the vibration mode. 7. At least one of the three types of ports is disposed on one main surface of the piezoelectric transformer,
The remaining two ports, one of the claims 1 to 6, characterized in that disposed on the other main surface of the piezoelectric transformer
The piezoelectric transformer according to claim 1 .