JP3391130B2 - High voltage generator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage generator, and more particularly to a high voltage generator suitable for use in an electrostatic actuator or the like.

[0002]

2. Description of the Related Art Conventionally, in a high voltage generator of this type, as shown in, for example, Japanese Patent Laid-Open No. 60-259770, an oscillation circuit, a capacitor and a piezoelectric element constitute a series resonance circuit. , Resonating the piezoelectric element at the resonance frequency of this series resonant circuit under the oscillating action of the oscillator circuit, generating a resonant voltage from the common terminal of the piezoelectric element and the capacitor, and multiplying this resonant voltage by the diode. There is a device that generates a high voltage by half-wave rectification.

[0003]

By the way, in such a high voltage generator, there is a demand to generate two kinds of high voltages, positive and negative, with respect to the ground potential. However, in order to meet this demand, it is usually necessary to employ one set of piezoelectric elements and one set of oscillation circuits for generation of positive and negative high voltages, respectively. Therefore,
In such a configuration, the same component is used repeatedly, the configuration becomes complicated, and the manufacturing cost increases.

Further, with the high voltage generator as described above, even if the double voltage can be generated by the half-wave rectification by the diode, the resonance voltage is taken out from the piezoelectric element by a single terminal, so that the full-wave rectification is performed. It is difficult to adopt the double voltage method. As a result, with half-wave rectification, there is a problem that a high voltage that is half that of full-wave rectification can be obtained.

Further, in the above high voltage generator,
A piezoelectric element used as a resonance element of a series resonance circuit requires a special device for holding the piezoelectric vibrator. For this reason, there is a problem in that the component cost of the piezoelectric element becomes high, and as a result, the cost of the high voltage generator becomes high. On the other hand, the present inventors have considered using a capacitor as a resonance element in the series resonance circuit instead of a piezoelectric element and directly extracting both positive and negative resonance voltages from both electrodes of the capacitor. saw.

However, according to such a method of extracting the resonance voltage, the DC component in the oscillation energy of the oscillation circuit is also extracted. Therefore, it was found that the DC level required for resonance of the series resonance circuit was shifted, and as a result, the resonance phenomenon of the series resonance circuit could not be properly maintained. On the other hand, when the resonance voltage is extracted from the electrode different from the extraction electrode of the resonance voltage of the capacitor through another capacitor, the extraction of the direct current component in the oscillation energy of the oscillation circuit is blocked by the other capacitor, and the oscillation occurs. It was found that it is possible to extract only the AC component in the energy. And it turned out that the resonance of the said series resonance circuit can be maintained appropriately by this.

Therefore, in order to deal with the above, the present invention suppresses the use of redundant overlapping members and effectively utilizes the capacitor to appropriately generate two types of high voltages. It is an object of the present invention to provide such a high voltage generator at low cost.

[0008]

In order to achieve the above object, the oscillating means (2
0, 20A, 30, 30A) and the first capacitor (5
0) and a second capacitor (4
0) and the resonance of the series resonance circuit according to the oscillation voltage from the oscillating means (20, 20A, 30, 30A).
A first voltage doubler full wave rectification means (60, 7) for receiving a resonance voltage from the first capacitor (50) side electrode (41) of the capacitor (40) and performing double voltage full wave rectification to generate a high voltage.
0) and the oscillation means (20, 2) of the second capacitor (40)
Second voltage doubler full wave rectifying means (8) for receiving the resonance voltage from the 0A, 30, 30A side electrode (42) through the third capacitor (100) and performing double voltage full wave rectification to generate a high voltage.
0, 90) and oscillating means (20 , 20A , 30,
30A) is a switching switch according to the resonance of the series resonance circuit.
Switching circuit (20) for switching and stepped columnar core
(31), the second capacitor (40) and the third capacitor
The winding start terminal that connects with (100) is the innermost circumference.
The outer circumference of the central small diameter portion (31a) of the core (31)
Secondary coil (37) and the outer circumference of this secondary coil
And a primary coil (36) for winding
Switched by coil with switching circuit (20)
Driven to oscillate the secondary coil (37),
And a high frequency transformer (30) for generating a swing voltage.
And are characterized .

[0009]

According to the second aspect of the invention, the oscillator
Stage (20, 20A, 30, 30A) and first capacitor
Second capacitor forming a series resonance circuit together with (50)
(40) and oscillation means (20, 20A, 30, 30A)
Along with the resonance of the series resonant circuit according to the oscillation voltage from
Electric power of the first capacitor (50) of the second capacitor (40)
Resonance voltage is received from the pole (41) and double voltage full wave rectification
First double voltage full-wave rectifying means (60, 7)
0) and the oscillation means (20, 2) of the second capacitor (40)
0A, 30, 30A) side electrode (42)
Double voltage full wave rectification through the third capacitor (100)
Second high voltage full-wave rectification means (8
0, 90) and oscillating means (20 , 20A , 30,
30A) is a pair of switching circuits (20A) that perform switching in opposite phases due to resonance of the series resonant circuit.
A), the stepped columnar core (31), and the winding start terminal (37a) connecting between the second capacitor (40) and the third capacitor (100) as the innermost circumference, and the center of the core (31). A secondary coil (37) wound around the outer circumference of the small diameter portion (31a), and a pair of primary coils (3) wound around the outer circumference of the secondary coil so as to form magnetic flux in opposite directions.
6, 36a), and the primary side coils are driven by the opposite phase switching of the pair of switching circuits (20A) to oscillate the secondary side coil (37) to generate the oscillation voltage. And a transformer (30A).

According to the invention described in claim 3 , in the high voltage generator according to claim 1 or 2 ,
And second voltage doubler full-wave rectification means (60, 70, 80, 9
0) generate high voltages having polarities different from each other. In addition, the reference numerals in parentheses of the above means and elements are as follows.
It shows a correspondence relationship with concrete means and elements described in the embodiments described later.

[0012]

According to the invention described in claims 1 to 3 , the second capacitor constitutes the series resonance circuit together with the oscillation means and the first capacitor. The first voltage-doubler full-wave rectifier receives the resonance voltage from the first capacitor-side electrode of the second capacitor as the series resonance circuit resonates according to the oscillation voltage from the oscillator, and receives the voltage-doubler full-wave rectification. Then, it is generated as a high voltage. Further, the second voltage-doubler full-wave rectification means receives the resonance voltage from the oscillation means side electrode of the second capacitor through the third capacitor, double-voltage full-wave rectification, and generates a high voltage.

In this case, since the first to third capacitors are independent of each other, the direct current component of the oscillation energy of the oscillation means is cut off from the double voltage rectification means by the first and second capacitors. Therefore, the resonance voltage of the second capacitor can be simultaneously taken out from the electrode on the first capacitor side and the electrode on the oscillation means side while maintaining the resonance of the series resonance circuit appropriately.

Therefore, the voltage doubler full wave rectification can be performed by the voltage doubler full wave rectification means for these resonance voltages, and the respective resonance voltages can be obtained as appropriate high voltages based on the voltage doubler full wave rectification. . As a result, in this type of high voltage generator, by using a capacitor instead of the piezoelectric element that is usually used in the series resonance circuit,
It is possible to generate two types of high voltages at the same time while surely eliminating the problems peculiar to the piezoelectric element and reducing the component cost.

According to the first aspect of the present invention, the switching circuit of the oscillating means switches in accordance with the resonance of the series resonance circuit, and the high frequency transformer is switching-driven by the switching circuit in its primary coil. The secondary coil is oscillated to generate the oscillation voltage.
Here, the secondary coil has the winding start terminal connecting between the second capacitor and the third capacitor as the innermost circumference, and winds the outer circumference of the central small diameter portion of the stepped columnar core. The side coil winds around the outer circumference of the secondary coil. Therefore,
The coil portion of the winding start terminal having the highest voltage is covered by the coil portion having a lower voltage and the surface of the central small diameter portion of the stepped columnar core.

As a result, the secondary coil 2 results in 2
Despite taking out various types of high voltage, a single secondary coil is sufficient, and it is not necessary to adopt a high voltage resistant secondary coil. Further, according to the invention described in claim 2 , the pair of switching circuits of the oscillating means perform switching in opposite phases due to the resonance of the series resonant circuit, and the high frequency transformer has the pair of primary side coils. The secondary side coil is driven by the opposite phase switching of the pair of switching circuits to oscillate and the oscillation voltage is generated.

Here, the secondary coil has the winding start terminal connecting between the second capacitor and the third capacitor as the innermost circumference and the outer circumference of the central small diameter portion of the stepped columnar core. A pair of primary coils are wound around the outer circumference of the secondary coil. Therefore, the coil portion of the winding start terminal having the highest voltage is covered by the coil portion having a lower voltage and the surface of the central small diameter portion of the stepped columnar core.

As a result, the secondary coil results in 2
Despite taking out various types of high voltage, a single secondary coil is sufficient, and it is not necessary to adopt a high voltage resistant secondary coil. The pair of primary coils are wound around the secondary side coil so as to form magnetic flux in opposite directions. Therefore, the secondary coil generates a voltage that is twice the output voltage of the single primary coil.

Therefore, the series resonance circuit resonates under this double output voltage, and the resonance voltage of the second capacitor is extracted as two types of high voltages through the double voltage rectification circuit. In such a case, as described above, the output voltage of the secondary side coil is twice the output voltage of the single primary side coil, so even if the input voltage to both primary coils is reduced, it is appropriate. It is possible to secure two types of high voltage.

According to the third aspect of the invention, the first and second voltage doubler full-wave rectification means generate high voltages having polarities different from each other. This allows both positive and negative high voltages to be extracted from a single high voltage generator. As a result, it is possible to provide a useful high voltage generator for an electrostatic actuator or the like that requires both positive and negative high voltages as drive voltages.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an example in which the high voltage generator according to the present invention is applied to an electrostatic actuator 10. The electrostatic actuator 10 simultaneously receives positive and negative high voltages generated as will be described later from the high voltage generator, and adjusts the light transmission amount of the sun visor or the like of the vehicle.

The high voltage generator includes a transistor circuit 20.
And a high frequency transformer 30 connected to the transistor circuit 20. The transistor circuit 20 includes a transistor 21, which is
At that base, the positive side terminal of the DC power supply +
B is connected. The base of the transistor 21 is connected via a capacitor 23 between both capacitors 40 and 50 described later. The emitter of the transistor 21 is grounded.

As shown in FIG. 2, the high frequency transformer 30 is provided with a stepped columnar ferrite core 31. The ferrite core 31 has both large diameter end portions 31b and 31c at both axial ends of the small diameter central portion 31a. Are integrally formed. However, the small-diameter central portion 31a is formed so as to be inclined from both axial ends thereof toward the outer peripheral surfaces of the large-diameter end portions 31b and 31c. Further, four rod-shaped electrodes 32 to 35 are embedded at the base of the axial end surface of the large-diameter end 31c.

The secondary coil 37 is wound around the outer periphery of the small-diameter central portion 31a of the ferrite core 31, and the winding start terminal 37a of the secondary coil 37 is connected to the electrode 32.
The winding end terminal of the secondary coil 37 is connected to the electrode 33. A primary coil 36 is wound around the outer peripheral surface of the secondary coil 37.
Is connected to the electrode 34 at its winding start terminal and is also connected to the base of the transistor 21 through the resistor 22. On the other hand, the winding end terminal of the primary coil 36 is connected to the electrode 35 and
1 is connected to the collector. The secondary coil 3
The number of turns of 7 is 18 times the number of turns of the primary coil 36.

The capacitor 40, as shown in FIG.
The negative electrode 41 is connected to the base of the transistor 21 through the capacitor 23.
The positive electrode 42 of 0 is grounded through the secondary coil 37 of the high frequency transformer 30. The secondary coil 37
The winding start terminal 37a is connected to between the capacitor 40 and the capacitor 100, and is located on the innermost circumference of the ferrite core 31.

The capacitor 50 constitutes a series resonance circuit together with the secondary coil 37 of the high frequency transformer 30 and the capacitor 40. The capacitor 50 is grounded at one end and is connected to the negative side of the capacitor 40 at the other end. It is connected to the electrode 41. According to the above configuration, the series resonant circuit switches the transistor 21 via the capacitor 23 at its resonant frequency.
As a result, the high frequency transformer 30 moves the transistor 21
Self-excited oscillation in response to switching of the primary coil 3
The DC voltage generated at 6 is output from the secondary coil 37 as a high frequency voltage. This means that the capacitor 40 resonates based on the high frequency voltage to generate a resonance voltage.

Both diodes 60 and 70 are connected to the capacitor 4
A voltage doubler full-wave rectifier circuit is formed together with 0, and the diode 60 is grounded at its anode and is connected to the negative electrode 41 of the capacitor 40 at its cathode. The diode 70 is connected to the negative electrode 41 of the capacitor 40 at its anode. here,
The cathode of the diode 60 and the anode of the diode 70 are isolated from the secondary coil 37 of the high frequency transformer 30 in terms of direct current by the capacitors 40 and 50.

As a result, both diodes 60 and 70 are
The resonant voltage of the capacitor 40 is subjected to double voltage full-wave rectification and output as a negative high voltage from the cathode of the diode 70. Further, both diodes 80, 90 are connected to both capacitors 40, 1
A double voltage full-wave rectification circuit is formed together with the diode 00, and the diode 80 is grounded at its cathode, while passing through the capacitor 100 at its anode.
Is connected to the positive electrode 42 of. Also, the diode 9
0 is connected at its cathode through the capacitor 100 to the positive electrode 42 of the capacitor 40.

As a result, both diodes 80 and 90 are
The resonance voltage of the piezoelectric element 40 is received through the capacitor 100, and double voltage full-wave rectification is performed to output a positive high voltage from the anode of the diode 90. In the present embodiment, the above-described capacitor 100 plays a role of DC-blocking the anode of the diode 80 and the cathode of the diode 90 from the secondary coil 37 of the high frequency transformer 30. Therefore, of the oscillation energy generated at the common connection point between the secondary coil 37 of the high frequency transformer 30 and the positive electrode 42 of the capacitor 40, only the AC component other than the DC component is extracted to the diodes 80 and 90 side through the capacitor 100. Be done.

In the present embodiment thus constructed,
The capacitor 50 is the secondary coil 3 of the high frequency transformer 30.
7 and the capacitor 40 form a series resonance circuit.
Therefore, the capacitor 40 generates a resonance voltage under the self-excited oscillation of the high frequency transformer 30 due to the resonance of the series resonance circuit. At this time, a negative resonance voltage appears on the electrode 41, while a positive resonance voltage appears on the electrode 42.

Therefore, the diodes 60 and 70 double-wave full-wave rectify the resonance voltage from the electrode 41 of the capacitor 40 to generate a negative high voltage. On the other hand, both diodes 80 and 9
0 is the electrode 4 of the capacitor 40 via the capacitor 100
It receives the resonant voltage from the circuit 2 and performs double voltage full-wave rectification to generate a positive high voltage. In this case, the DC component of the oscillating energy of the high frequency transformer 30 is determined by the capacitors 40, 50, 10
0 disconnects each diode 60-90.
Therefore, the resonance voltage of the capacitor 40 is properly taken out through the electrode 41 and properly taken out through the electrode 42 and the capacitor 100 while the resonance phenomenon of the series resonant circuit is appropriately maintained. Therefore, the positive and negative high voltages can be properly taken out by the double voltage full-wave rectifier circuit.

As described above, according to the high voltage generator using only the capacitor, it is possible to generate positive and negative high voltages without causing a problem peculiar to the piezoelectric element. Here, in generating two types of positive and negative high voltages, the oscillation output of the single secondary coil 37 of the high frequency transformer 30 is used. However, the high voltage is the winding of the secondary coil 37. Only the starting terminal 32 is provided. further,
The voltage distribution of both coils 36, 37 in the ferrite core 31 is the highest voltage in the vicinity of the surface of the small-diameter central portion 31a, and becomes gradually lower toward the outside. Further, as described above, the small-diameter central portion 31a is formed so as to be inclined from both ends in the axial direction toward the outer peripheral surfaces of the large-diameter end portions 31b and 31c, so that the potential difference between the adjacent coil portions can be reduced. .

Therefore, the high voltage portion of both coils 36 and 37 is covered by the coil portion corresponding to a voltage portion slightly lower than this and the surface of the small diameter central portion 31a of the ferrite core 31. Therefore, the high frequency transformer 30 for extracting the high voltage can be configured without using the winding having excellent high voltage resistance as the secondary coil, and such a high frequency transformer can be effectively utilized. hand,
It is possible to generate the positive and negative two types of high voltages described above.

The input / output voltage characteristics of the high voltage generator in the first embodiment were obtained as shown in FIG. According to this, an output voltage of 600 V was obtained on both positive and negative sides, for example, when the input voltage was 9 V and the load resistance was 1 MΩ. Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Instead of the transistor circuit 20 and the high frequency transformer 30 described in the first embodiment, the second embodiment will be described. The characteristic of the configuration is that the transistor circuit 20A and the high frequency transformer 30A are adopted.

As shown in FIG. 4, the transistor circuit 20A is configured by additionally adopting the transistor 24, the oscillation starting resistor 25 and the capacitor 26 in the transistor circuit 20. The transistor 24 is grounded at its collector, and the base of the transistor 24 is grounded through the resistor 25 and connected to the base of the transistor 21 through the capacitor 26.

Here, the transistor 24 is adapted to switch at its base in synchronism with the base of the transistor 21 via the capacitor 26 and in a phase opposite to the switching of the transistor 21. Note that the transistor 24 has characteristics compatible with the transistor 21. As shown in FIG. 5, the high frequency transformer 30A includes the primary coil 36 in the high frequency transformer 30.
In addition, the primary coil 36a is wound around the outer circumference of the primary coil 36. However, both primary side coils 36, 36a are wound in directions in which magnetic fluxes in opposite directions are generated by simultaneous energization.

Here, the primary coil 36a is connected at its winding start terminal to the rod-shaped electrode 39a embedded in the axial end face of the large-diameter end 31c, and to the positive terminal + B of the DC power source. It is supposed to be connected. on the other hand,
The winding end terminal of the primary side coil 36a has a large-diameter end portion 31.
It is connected to the rod-shaped electrode 39b embedded in the axial end face of c and is connected to the emitter of the transistor 24. The other structure is similar to that of the first embodiment.

In the second embodiment thus constructed, both transistors 21 and 2 of the transistor circuit 20A are formed.
Since 4 has switching characteristics of opposite phases to each other, when current flows through one of the primary coils 36 and 36a of the high frequency transformer 30A, no current flows through the other primary coil. However, as described above, since both the primary side coils 36 and 36a are wound in the directions in which the magnetic fluxes in the opposite directions are generated, the secondary side coil 37 outputs the output voltage of the single primary side coil. Generates twice the voltage.

Therefore, the series resonance circuit resonates under this doubled output voltage, and the resonance voltage of the capacitor 40 is extracted as positive and negative two types of high voltage through the double voltage rectification circuit as in the first embodiment. Be done. In this case, as described above, the output voltage of the secondary coil 37 is twice the output voltage of the single primary coil, so that even if the output voltage of the DC power supply drops, the positive and negative values are appropriate. It is possible to secure a high voltage. Other functions and effects are similar to those of the first embodiment.

Incidentally, when the input / output voltage characteristics of the high voltage generator in the second embodiment are compared with the input / output voltage characteristics of the high voltage generator in the first embodiment, the results shown in FIG. 6 are obtained. Was obtained. Here, the straight line L1 in FIG.
Shows the input / output voltage characteristic of the high voltage generator in the first embodiment, while the straight line L2 shows the input / output voltage characteristic of the high voltage generator in the second embodiment.

According to this, for example, on the straight line L1, 1
The output voltage is 600V for an input voltage of 2V, while the straight line L2 is 1200V for an input voltage of 12V.
Output voltage. Therefore, it can be confirmed that the second embodiment can obtain a higher boosting ratio than the first embodiment. In implementing the present invention, one of the positive and negative high voltages from the double voltage rectifier circuit in each of the above embodiments may be inverted in polarity so that both of them are taken out as a high voltage of the same polarity. . As a result, it is possible to generate two types of high voltage having the same polarity while being cut off from the high frequency transformer in terms of direct current.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of the high frequency transformer of FIG.

FIG. 3 is an input / output voltage characteristic diagram in the first embodiment.

FIG. 4 is a circuit configuration diagram showing a second embodiment of the present invention.

5 is a cross-sectional view of the high frequency transformer of FIG.

FIG. 6 is a comparison characteristic diagram of input / output voltages in the first and second embodiments.

[Explanation of symbols]

20, 20A ... Transistor circuit, 30, 30A
..High-frequency transformer, 31 ... Core, 31a ... Central small-diameter portion, 36, 36a ... Primary coil, 37 ...
Secondary coil, 40, 50, 100 ... Capacitor, 41 ... Negative electrode, 42 ... Positive electrode, 60 to 90 ... Diode.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidetoshi Suzuki 390 Umeda, Kosai City, Shizuoka Prefecture Asmo Co., Ltd. (56) References JP 62-135266 (JP, A) JP 61-26465 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02M 3/28 H02M 3/24 H02M 7/10

Claims (3)

(57) [Claims] 1. A series together with an oscillation means and a first capacitor
A second capacitor forming a resonance circuit, and the series resonance circuit according to the oscillation voltage from the oscillation means.
The first capacitor of the second capacitor due to the resonance of
Resonant voltage is received from the side electrode and double voltage full wave rectification
First double voltage full-wave rectifying means and the resonance current from the oscillating means side electrode of the second capacitor.
Pressure is received through the third capacitor and double voltage full wave rectification
A doubling voltage full-wave rectifying means that is generated as a voltage, and the oscillating means performs switching with resonance of the series resonant circuit, a stepped columnar core, the second capacitor, and the third capacitor. A secondary coil having a winding start terminal connected to the capacitor as the innermost circumference and winding the outer circumference of the central small diameter portion of the core;
A secondary coil wound around the outer periphery of the secondary coil, and the secondary coil is oscillated by the switching circuit driven by the switching circuit.
High voltage generator, characterized in that it comprises a high frequency transformer for generating the oscillating voltage. 2. Series together with oscillating means and a first capacitor
A second capacitor forming a resonance circuit, and the series resonance circuit according to the oscillation voltage from the oscillation means.
The first capacitor of the second capacitor due to the resonance of
Resonant voltage is received from the side electrode and double voltage full wave rectification
First double voltage full-wave rectifying means and the resonance current from the oscillating means side electrode of the second capacitor.
Pressure is received through the third capacitor and double voltage full wave rectification
Second doubling voltage full-wave rectification means that is generated as a voltage, and the oscillating means switches a pair of switching circuits that switch in opposite phases in accordance with the resonance of the series resonance circuit, a stepped columnar core, and A secondary coil having a winding start terminal connected between the second capacitor and the third capacitor as the innermost circumference and winding the outer circumference of the central small diameter portion of the core;
The secondary side coil has a pair of primary side coils wound around the outer circumference so as to form magnetic flux in opposite directions, and these primary side coils are switched by the opposite phase of the pair of switching circuits. It is driven to oscillate the secondary coil, high voltage generator, characterized in that it comprises a high frequency transformer for generating the oscillating voltage. Wherein the first and second voltage doubler full wave rectification means, a high-voltage generator according to claim 1 or 2, characterized in that for generating the opposite polarity of the high voltage to each other.