JP2008206317A - High-voltage power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-voltage power supply circuit that allows high-speed change of an output voltage while having high responsiveness and outputs a DC high voltage with a small configuration without requiring a large-capacity winding transformer. <P>SOLUTION: The high-voltage power supply circuit 100 is configured by serially connecting a plurality of DC voltage conversion circuits 40i (i=1-N). Each DC voltage conversion circuit 40 from a kth-stage DC voltage conversion circuit 40k (k is a prescribed integer of ≥1 and ≤N) to an Nth-stage DC voltage conversion circuit 40<SB>N</SB>is respectively provided with switch units 41, 42 including a series circuit of a plurality of switch elements 44. A diode 45 and a resistor 46 are connected to each switch element 44 of each switch unit 41, 42 in parallel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high voltage power supply circuit capable of outputting a positive or negative DC high voltage.

  Conventionally, as a DC high-voltage power supply circuit, a high-capacity DC high-voltage power supply that generates a high DC voltage by rectifying an AC high voltage obtained by boosting an AC output of a commercial AC power supply by a winding transformer by a rectifier circuit Widely known as a circuit. Furthermore, as a relatively small-capacity DC high-voltage power supply circuit, a high-frequency pulsed DC voltage is boosted by a winding transformer, and the output on the secondary coil side of this winding transformer is as shown in, for example, Patent Document 1. It is known that a DC high voltage is generated by rectification and boosting by a voltage doubler rectifier circuit called a Cockcroft-Walton circuit. In addition, in the thing of patent document 1, the positive polarity DC high voltage power supply circuit which generate | occur | produces positive polarity DC high voltage, and the negative polarity DC high voltage power supply circuit which generate | occur | produces negative polarity DC high voltage are combined, and those DC high voltage power supplies By alternately operating the circuit periodically, a positive DC high voltage and a negative DC high voltage are alternately generated, and the positive and negative DC high voltages are applied to the discharge electrode of the static eliminator. Thus, an alternating high voltage is applied to the discharge electrode.

  The high-voltage power supply circuit as described above is used in various applications, for example, as a power supply circuit for a static eliminator that generates a corona discharge in the air or a power supply circuit for generating plasma.

  By the way, the above-described conventional DC high voltage power supply requires a relatively large capacity winding transformer, so that it is difficult to reduce the size and weight of the power supply circuit.

  In recent years, there has been a need for a DC high-voltage power supply (a DC high-voltage power supply with high output voltage responsiveness to changes in input voltage) that can change the output voltage in a pulsed manner for the purpose of improving the static elimination performance of the static elimination device. The nature is increasing. However, it is difficult to realize a circuit capable of changing the output voltage at high speed in a DC high-voltage power supply circuit having a rectifier circuit such as the Cockcroft-Walton circuit. This is because in a DC high-voltage power supply circuit having a rectifier circuit such as a Cockcroft-Walton circuit, power transmission between the input side and the output side can be performed only in one direction from the input side to the output side. Because.

  On the other hand, as a DC voltage conversion circuit (DC-DC converter) that can convert a positive or negative DC voltage into a higher DC voltage without using a winding transformer, for example, FIG. 1 or FIG. The circuit shown in FIG. The DC voltage conversion circuit will be described below with reference to FIGS. FIG. 1 is a circuit configuration diagram of a main part of a DC voltage conversion circuit capable of boosting a positive DC voltage, and FIG. 2 is a timing chart showing an on / off operation of a switch element provided in the DC voltage conversion circuit of FIG. FIG. 3 is a circuit configuration diagram of a main part of a DC voltage conversion circuit capable of boosting a negative DC voltage. These DC voltage conversion circuits are known circuits.

  Referring to FIG. 1, this DC voltage conversion circuit 1 includes a switch element circuit 4 formed by connecting two switch elements 2 and 3 in series, a coil 5, a capacitor 6, and two diodes 7 and 8. Is provided. Each of the switch elements 2 and 3 is a switch element that can be controlled by a control signal. In the illustrated example, an n-channel FET is used as each of the switch elements 2 and 3, and the switch element circuit 4 is formed by connecting the drain terminal of the FET 2 that is the switch element 2 and the source terminal of the FET 3 that is the switch element 3. It is configured. However, either one or both of the switch elements 2 and 3 may be constituted by a p-channel FET. Or each switch element 2 and 3 may be comprised by the switching transistor.

  Diodes 7 and 8 are connected in parallel to the switch elements 2 and 3, respectively. In this case, one end 9 on the switch element 2 side of the switch element circuit 4 is a reference potential portion 9, and the other end 10 on the switch element 3 side of the switch element circuit 4 is a positive high-voltage side positive potential portion 10. 8, each of the switch elements 2, so that the forward direction is a direction from the reference potential portion 9 toward the high-voltage side positive potential portion 10 (opposite to the energization direction of the switch elements 2, 3). 3 are connected in parallel.

  One end 11 of the coil 5 is connected to a location between the switch element 2 and the switch element 3 of the switch element circuit 4. The capacitor 6 is connected in parallel with the switch element circuit 4 between the reference potential portion 9 and the high-voltage side positive potential portion 10.

  In the DC voltage conversion circuit 1 configured as described above, the other end 12 of the coil 5 is set to a low voltage side positive potential part 12 that is positive with respect to the reference potential part 9, and the reference potential part is connected to the low voltage side positive potential part 12. The switch elements 2 and 3 are alternately turned on and off at a high speed while a positive DC input voltage ea (> 0) is input to 9. Thus, a positive DC voltage eb obtained by boosting the DC input voltage ea between the high-voltage side positive potential unit 10 and the reference potential unit 9 (the high-voltage side positive potential unit 10 is positive with respect to the reference potential unit 9). Direct current voltage) can be generated.

  In the DC voltage conversion circuit 1 in the illustrated example, the switching elements 2 and 3 are alternately switched by inputting rectangular wave pulses having a waveform as shown in FIG. 2 to the gates of the FETs (switching elements) 2 and 3. Can be turned on and off.

  Supplementally, in the rectangular wave pulse shown in FIG. 2, one of the switch elements 2 and 3 has the same ON period and the other OFF period. In other words, the switching elements 2 and 3 are not turned on at the same time. However, since this dead period is a minute period with respect to the ON / OFF cycle of the switch elements 2 and 3, in the description of this specification, the dead period is ignored for convenience of understanding.

  Here, the ratio of the period during which the switching elements 2 and 3 are turned on in the period of one cycle T (the ratio with respect to one period T) is called the duty ratio of the switching elements. As shown, the on / off duty ratio of the second switch element 3 is α (0 <α <1), and the on / off duty ratio of the first switch element 2 is 1−α. At this time, in the DC voltage conversion circuit 1 of FIG. 1, the relationship between the DC input voltage ea and the DC voltage eb depends on the value of the duty ratio α and is given by the following equation (1).

eb = (1 / α) × ea (1)
Therefore, the DC voltage eb of the high-voltage side positive potential portion 10 is obtained by boosting the DC input voltage ea of the low-voltage side positive potential portion 12 by (1 / α) times. As the duty ratio α of the second switch element 2 is reduced (the duty ratio 1-α of the first switch element 3 is increased), the degree of boosting is increased.

  Supplementally, in the DC voltage conversion circuit 1, power can be transmitted bidirectionally between the low voltage side positive potential unit 12 and the high voltage side positive potential unit 10. For this reason, the DC voltage eb is changed by alternately turning on and off the switch elements 2 and 3 while applying a positive DC voltage eb to the high-voltage positive potential part 10 and the reference potential part 9. It is also possible to generate a positive DC voltage ea that is stepped down in accordance with the relationship of Expression (1) in the low-voltage side positive potential portion 12. In other words, the DC voltage conversion circuit 1 functions as a bidirectional DC-DC converter.

  The DC voltage conversion circuit 1 shown in FIG. 1 can boost a positive DC voltage as described above, but can also boost a negative DC voltage with a similar circuit configuration. . An example of the circuit is a DC voltage conversion circuit 21 shown in FIG. The DC voltage conversion circuit 21 will be described below.

  This DC voltage conversion circuit 21 includes a switch element circuit 24 formed by connecting two switch elements 22 and 23 in series, a coil 25, a capacitor 26, and two diodes 27 and 28 as shown in FIG. This is the same as the DC voltage conversion circuit 1 of FIG. 3, n-channel FETs are used as the switch elements 22 and 23, and the source terminal of the FET 22 as the switch element 22 and the drain terminal of the FET 23 as the switch element 23 are connected. Thus, the switch element circuit 24 is configured. However, one or both of the switch elements 22 and 23 may be constituted by a p-channel FET. Or each switch element 2 and 3 may be comprised by the switching transistor.

  In the DC voltage conversion circuit 21 of FIG. 3, one end 29 on the switch element 22 side of the switch element circuit 24 is a reference potential portion 29, and the other end 30 on the switch element 23 side is a negative high voltage side negative potential portion 30. Each of the diodes 27 and 28 has a forward direction that is directed from the high-voltage-side negative potential portion 30 toward the reference potential portion 29 (opposite to the energization direction of the switch elements 22 and 23). The switch elements 22 and 23 are connected in parallel.

  1, one end 31 of the coil 25 is connected to a portion of the switch element circuit 24 between the switch element 22 and the switch element 23, and the reference potential portion 29 and the high-voltage side negative potential portion are connected. 30, a capacitor 26 is interposed in parallel with the switch element circuit 24.

  In the DC voltage conversion circuit 21 of FIG. 3 configured as described above, the other end 32 of the coil 25 is a low-voltage-side negative potential portion 32 that is negative with respect to the reference potential portion 29, and the low-voltage-side negative potential portion 32 The first and second switch elements 22 and 23 are alternately turned on and off at high speed while inputting a negative DC input voltage −ea (<0) to the reference potential portion 29, thereby increasing the high voltage side. A negative DC voltage -eb obtained by boosting the DC input voltage -ea between the negative potential portion 30 and the reference potential portion 29 (the high-voltage side negative potential portion 30 has a negative polarity with respect to the reference potential portion 29. DC voltage) can be generated.

  In this case, if the on / off duty ratio of the switch element 23 is α and the on / off duty ratio of the switch element 22 is 1−α, the DC input voltage −ea and DC voltage −eb in the DC voltage conversion circuit 21 Is given by the following equation (2).

−eb = (1 / α) × (−ea) (2)
Accordingly, the DC voltage −eb of the high-voltage side negative potential unit 30 is obtained by boosting the DC input voltage −ea of the low-voltage side negative potential unit 32 by (1 / α) times. As the duty ratio α of the switch element 22 decreases (as the duty ratio 1−α of the switch element 23 increases), the degree of boosting increases.

  In this DC voltage conversion circuit 21 as well, power can be transmitted bidirectionally between the low voltage side negative potential unit 32 and the high voltage side negative potential unit 30. Therefore, the switching elements 22 and 23 are alternately turned on and off while applying a negative DC voltage −eb between the high-voltage side negative potential section 30 and the reference potential section 29, so that the DC voltage − It is also possible to generate a negative DC voltage −es obtained by stepping down ea in accordance with the relationship of the expression (2) in the low-voltage negative potential portion 32. In other words, the DC voltage conversion circuit 21 also functions as a bidirectional DC-DC converter.

  The DC voltage conversion circuits 1 and 21 shown in FIG. 1 or 3 described above can boost a positive or negative DC voltage without requiring a winding transformer. In any DC voltage conversion circuit 1, 21, between the input side and the output side (between the low voltage side positive potential unit 12 and the high voltage side positive potential unit 10, or between the low voltage side negative potential unit 32 and the high voltage side. Since bidirectional power transmission is possible between the negative potential portion 30 and the DC voltage on the input side, the DC voltage on the output side changes with high responsiveness (rapid response). Therefore, the DC voltage conversion circuits 1 and 21 are considered to be suitable for forming a high-voltage power supply circuit having a small size and high response.

  However, in the DC voltage conversion circuits 1, 21, the DC voltage of the high voltage side potential units 10, 30 is directly applied to the switch element circuits 4, 24, so that the switch elements 2, 3, 22, 23, the diode 7, Under the limitation of the breakdown voltage of 8, 27, 28, the single DC voltage conversion circuit 1, 21 cannot substantially generate a sufficiently high DC voltage (DC high voltage) of several kV. It was a thing.

Further, for example, in order to obtain a positive DC high voltage, a plurality of DC voltage conversion circuits 1 are used, and the output voltage of the first DC voltage conversion circuit 1 is input to the second DC voltage conversion circuit 1. The output voltage of the second DC voltage conversion circuit 1 is input to the third DC voltage conversion circuit 1, so that a plurality of DC voltage conversion circuits 1 are simply connected in series, and stepped. Even when boosting is performed, a high-voltage DC voltage is directly applied to the switch element circuits 4 and 24 of the DC voltage conversion circuit 1 on the rear stage side. For this reason, if a plurality of DC voltage conversion circuits 1 are simply connected in series, as with the case where a single DC voltage conversion circuit 1 is used, the switch elements 2 and 3 and the diodes 7 and 8 are restricted in withstand voltage. It is practically impossible to generate a sufficiently high DC voltage (DC high voltage). This is the same even when a plurality of DC voltage conversion circuits 21 of FIG. 3 are connected in series.
JP 2000-58290 A

  The present invention has been made in view of the background described above, has high responsiveness, can change the output voltage at high speed, and has a small configuration without requiring a large-capacity winding transformer. An object of the present invention is to provide a high voltage power supply circuit capable of outputting a positive or negative DC high voltage.

  The high-voltage power supply circuit of the present invention includes a positive-polarity high-voltage power supply circuit that generates a positive DC high voltage and a negative-polarity high-voltage power supply circuit that generates a negative DC high voltage. Schematically explaining these high-voltage power supply circuits, the positive-polarity high-voltage power supply circuit is based on a DC voltage conversion circuit having a configuration as shown in FIG. 1 or a similar DC voltage conversion circuit as a basic element circuit. The plurality of element circuits are connected in series. The negative high-voltage power supply circuit according to the present invention has a DC voltage conversion circuit having the configuration shown in FIG. 3 or a DC voltage conversion circuit similar thereto as a basic element circuit, and a plurality of the element circuits are connected in series. Connected to and configured.

  The high-voltage power supply circuit of the present invention will be described below. In the description of the present invention, for convenience of understanding the present invention, reference numerals shown in FIG. 4 to FIG. In that case, when it is necessary to distinguish individual DC voltage conversion circuits provided in the high-voltage power supply circuit of the present invention, a subscript “i” (i: integer) corresponding to the number i of each DC voltage conversion circuit is used. Attached. Of course, the reference numerals are not intended to limit the present invention.

  In order to achieve the above object, the positive high-voltage power supply circuit of the present invention (see FIGS. 4 and 6) includes a plurality of switch elements (2, 3 or 44) that can be turned on and off in series. One end of the switch element circuit connected to the reference potential portion (9) and the other end of the switch element circuit as a high potential side positive potential portion (10) having a positive potential with respect to the reference potential portion. The diode (7) connected in parallel to each of the plurality of switch elements (2, 3 or 44) so that the direction from the reference potential section (9) toward the high-voltage side positive potential section (10) is the forward direction. , 8 or 45), a capacitor (6) connected in parallel with the switch element circuit between the reference potential section (9) and the high voltage side positive potential section (10), and the switch element circuit A set of adjacent switches A coil (5) having one end connected to a location between the children, the other end of the coil (5) as the low-voltage positive potential section (12), and the low-voltage positive potential section (12) and the reference All switches that are closer to the reference potential portion (9) than a portion between the predetermined set of switch elements while applying a positive DC input voltage (ea) to the potential portion (9) By alternately turning on and off the first switch means made up of elements and the second switch means made up of all switch elements located closer to the high-voltage-side positive potential section (10) than the location, the high-voltage side A DC voltage conversion circuit in which a boosting operation is performed to generate a positive DC voltage (eb) formed by boosting the DC input voltage (ea) between a positive potential section (10) and a reference potential section (9). 40) N (N: integer greater than or equal to 2).

In the positive high-voltage power supply circuit of the present invention, one of the N DC voltage conversion circuits (40) is a first-stage DC voltage conversion circuit, and the other DC voltage conversion circuits are n-th stage DC. When the voltage conversion circuit (n: integer from 2 to N) is used, the N DC voltage conversion circuits (40) have the same potential in their respective reference potential portions (9) and the nth stage DC. low voltage side positive potential portion of the voltage conversion circuit (40 _n) is (12 _n) becomes the same potential high voltage side positive potential portions and (10 _n-1) of the n-1 stage DC voltage converter (40 _n-1) Connected as
First switch means and second switch of each DC voltage conversion circuit from at least a predetermined k-th stage DC voltage conversion circuit (k is a predetermined integer of 1 or more and N or less) to the N-th stage DC voltage conversion circuit The number of the switch elements (44) constituting each means is plural, and a resistor (46) is connected in parallel to each switch element (44) of each switch means.

  In the positive-polarity high-voltage power supply circuit of the present invention or the negative-polarity high-voltage power supply circuit of the present invention to be described later, turning on the first switch means means that all the switch elements constituting the first switch means Is turned on at the same time, and turning off the first switch means means turning off all the switch elements constituting the first switch means at the same time. The same applies to ON / OFF of the second switch means.

According to the positive polarity high-voltage power supply circuit of the present invention, the output voltage (eb _n-1 ) of the n-1st stage DC voltage conversion circuit (40 _n-1 ) is converted into the nth stage DC voltage conversion circuit (40 _n ). Will be input. Then, the DC voltage conversion circuit (40) is boosted by alternately turning on and off the first switch means and the second switch means of each DC voltage conversion circuit (40).

As a result, the DC input voltage (ea ₁ ) input to the first stage DC voltage conversion circuit (40 ₁ ) is sequentially stepped by the _second to _N- th stage DC voltage conversion circuits (40 ₂ to 40 _N ). And the high-voltage DC voltage (eb _N ) is finally output from the Nth stage DC voltage conversion circuit (40 _N ).

  In this case, the output voltage (eb) of each DC voltage conversion circuit (40) increases as the number of stages of the DC voltage conversion circuit increases, and as a result, the maximum voltage that can act between both ends of each switch means. Also grows. However, a plurality of the switch elements (44) respectively constituting the first switch means and the second switch means of each DC voltage conversion circuit from the k-th stage DC voltage conversion circuit to the N-th stage DC voltage conversion circuit are provided. And a resistor (46) is connected in parallel to each switch element (44) of each switch means. For this reason, the output voltage of the DC voltage conversion circuit is connected to a series circuit of switch elements (44) constituting each switch means of each DC voltage conversion circuit from the k-th DC voltage conversion circuit to the N-th DC voltage conversion circuit. Even if a voltage of the same level is applied, a voltage obtained by dividing the voltage by the resistor acts on each switch element and a diode connected in parallel thereto. For this reason, the voltage which acts on the switch element and the diode of each DC voltage conversion circuit from the k-th stage DC voltage conversion circuit to the N-th stage DC voltage conversion circuit can be suppressed to a voltage within the breakdown voltage. Further, since the output voltage of each DC voltage conversion circuit other than each DC voltage conversion circuit from the k-th stage DC voltage conversion circuit to the N-th stage DC voltage conversion circuit can be suppressed low, the DC voltage conversion Even if the number of switch elements of each switch means in the circuit is one, the voltage acting on the switch element and the diode connected in parallel to the switch element can be suppressed to a voltage within the breakdown voltage.

  As a result, according to the positive polarity high voltage power supply circuit of the present invention, it is possible to output a positive DC high voltage with a small configuration without requiring a large capacity winding transformer. In addition, each DC voltage conversion circuit is capable of bidirectional power transmission between the input side and the output side thereof, so that the output voltage can be changed at high speed with high responsiveness.

  Next, the negative high voltage power supply circuit according to the present invention (see FIGS. 5 and 6) includes a plurality of switch elements (22, 23, or 44) that can be turned on and off in order to achieve the above-described object. A switch element circuit formed by connecting the switch element circuit in series, one end of the switch element circuit at one end with a reference potential portion (29), and the other end with a negative potential portion at a high voltage side that is negative with respect to the reference potential portion ( 30) and connected in parallel to each of the plurality of switch elements (22, 23 or 44) so that the direction from the high-voltage side negative potential portion (30) toward the reference potential portion (29) is a forward direction. A diode (27, 28 or 45), a capacitor (26) connected in parallel with the switch element circuit between the reference potential section (29) and the high-voltage side negative potential section (30), and the switch element circuit Next to each other A coil (25) having one end connected to a position between a predetermined set of matching switch elements, and the other end of the coil (25) as a low-voltage negative potential section (32). While applying a negative DC input voltage (−ea) between the part (32) and the reference potential part (29), the reference potential part ( 29) The first switch means composed of all switch elements existing closer to the switch and the second switch means composed of all switch elements located closer to the high-voltage-side negative potential section (30) than the relevant portion are alternately turned on By turning off, a negative DC voltage (-eb) is generated between the high-voltage negative potential portion (30) and the reference potential portion (29) by boosting the DC input voltage (-ea). DC voltage conversion circuit (50) in which the boosting operation is performed Pieces (N: 2 or more integer) provided.

In the negative high voltage power supply circuit according to the present invention, one of the N DC voltage conversion circuits (50) is a first stage DC voltage conversion circuit, and the other DC voltage conversion circuit is an nth stage DC. When the voltage converter circuit (n: integer from 2 to N) is used, the N DC voltage converter circuits (50) have the same potential at their respective reference potential parts (29) and the nth stage DC. the same potential high voltage side positive potential portions and (30 _n-1) of the low pressure side positive potential portion (32 _n) is the n-1 stage DC voltage converter (50 _n-1) of the voltage conversion circuit (50 _n) The first of the DC voltage conversion circuits (50) from at least a predetermined k-th stage DC voltage conversion circuit (k is a predetermined integer between 1 and N) to the N-th stage DC voltage conversion circuit. Switch elements (4) constituting the switch means and the second switch means respectively. The number of) a plurality, characterized in that connecting the resistance (46) in parallel to the switching elements (44) of each switch means.

According to the negative polarity high voltage power supply circuit of the present invention, the DC input voltage (−ea ₁ ) input to the first stage DC voltage conversion circuit (50 ₁ ) is the same as the positive polarity high voltage power supply circuit of the present invention. The second stage to the Nth stage DC voltage conversion circuit (50 ₂ to 50 _N ) are stepped up step by step and finally from the Nth stage DC voltage conversion circuit (50 _N ), the high voltage DC voltage (eb _N ) will be output.

  In this case, similarly to the negative high voltage power supply circuit of the present invention, the first switch means and the second switch means of each DC voltage conversion circuit from the kth DC voltage conversion circuit to the Nth DC voltage conversion circuit are provided. A plurality of the switching elements (44) constituting each of the switching elements (44) are provided, and a resistor (46) is connected in parallel to each switching element (44) of each switching means. For this reason, the voltage which acts on the switch element and the diode of each DC voltage conversion circuit from the k-th stage DC voltage conversion circuit to the N-th stage DC voltage conversion circuit can be suppressed to a voltage within the breakdown voltage. Further, since the output voltage of each DC voltage conversion circuit other than each DC voltage conversion circuit from the k-th stage DC voltage conversion circuit to the N-th stage DC voltage conversion circuit can be suppressed low, the DC voltage conversion Even if the number of switch elements of each switch means in the circuit is one, the voltage acting on the switch element and the diode connected in parallel to the switch element can be suppressed to a voltage within the breakdown voltage.

  As a result, the negative high voltage power supply circuit of the present invention can output a positive DC high voltage with a small configuration without requiring a large capacity winding transformer. In addition, each DC voltage conversion circuit is capable of bidirectional power transmission between the input side and the output side thereof, so that the output voltage can be changed at high speed with high responsiveness.

  Next, embodiments of the present invention will be described with reference to the drawings. First, an embodiment of a positive high voltage power supply circuit according to the present invention will be described with reference to FIGS. FIG. 4 is a circuit configuration diagram of a positive high voltage power supply circuit according to the present embodiment, and FIG. 5 is a circuit configuration diagram of a switch unit provided in the positive high voltage power supply circuit.

  Referring to FIG. 4, the positive high-voltage power supply circuit 100 according to the present embodiment is configured to sequentially add a plurality (N) of DC voltage conversion circuits 40 i (i = 1, 2,..., N) (subscript i). In order) and connected in series. In the illustrated example, N = 3. Hereinafter, each DC voltage conversion circuit 40i may be referred to as an i-th DC voltage conversion circuit 40i. Further, in order to distinguish the constituent elements of each DC voltage conversion circuit 40i, a suffix “i” is added to the reference numerals of the constituent elements as necessary.

Each DC voltage conversion circuit 40i is the same as the DC voltage conversion circuit 1 shown in FIG. 1 or a part of the configuration thereof is changed. In this embodiment, the first stage DC voltage converter 40 ₁ is the same as the DC voltage converter 1 of FIG. Thus, for the first stage DC voltage converter 40 ₁ are denoted by the same reference numerals as FIG. 1 (or subscript reference numerals obtained by adding the letter "1") as its component, the description thereof is omitted.

On the other hand, in the present embodiment, each of the DC voltage conversion circuits 40i (i = 2 to N) from the _second stage DC voltage conversion circuit 402 to the Nth stage DC voltage conversion circuit 40 _N is the DC voltage conversion circuit of FIG. The parallel circuit composed of one switch element 2 and diode 7 and the parallel circuit composed of switch element 3 and diode 8 are replaced by switch units 41i and 42i, which will be described later, respectively.

  That is, each DC voltage conversion circuit 40i (i = 2 to N) from the second stage to the Nth stage includes switch units 41i and 42i, a coil 5i, and a capacitor 6i. In this case, each of the switch units 41i and 42i includes two current input / output portions 43a and 43b. The current input / output portions 43a and 43b correspond to the drain and source of the n-channel FET as each switch element 2 and 3 of the first stage DC voltage conversion circuit 40i. The switch units 41i and 42i are connected in series by connecting the current input / output part 43a of the switch unit 41i and the current input / output part 43b of the switch unit 42i to each other. Further, the current input / output part 43b of the switch unit 41i is a reference potential part 9i, and the current input / output part 43a of the switch element 42i is a high-voltage side positive potential part 10i. Between these, a capacitor is connected in parallel with the series circuit of the switch units 41i, 42i. 6i is connected. Furthermore, one end of the coil 5i is connected to a location between the switch unit 41i and the switch unit 42i, and the other end of the coil 5i is a low-voltage positive potential portion 12i.

  Each of the switch units 41i and 42i has the same configuration. The circuit configuration will be described with reference to FIG. 5. Each switch unit 41i, 42i is connected in parallel to a series circuit in which a plurality of switch elements 44 are connected in series and to each of the switch elements 44 of this series circuit. It comprises a diode 45 and a resistor 46, and a drive circuit 47 for turning on / off the switch element 44. In the present embodiment, each switch element 44 is composed of an n-channel FET. One end of the series circuit of these switch elements 44 (the drain of the uppermost switch element 44 (n-channel FET) in FIG. 5) is used as the current input / output portion 43a, and the other end (the lowermost switch element 44 in FIG. 5 ( The source of the n-channel FET) is the current input / output part 43b. Therefore, the series circuit of the plurality of switch elements 44 of the switch unit 41i and the series circuit of the plurality of switch elements 44 of the switch unit 42i are connected in series, and the positive polarity high-voltage power supply circuit of the present invention is connected by the series connection. That is, the switch element circuit in FIG. The number of switch elements 44 in the switch element circuit is the sum (even number) of the number of switch elements 44 in each switch unit 41i, 42i. Further, the switch element 44 closest to the current input / output part 43a of the switch unit 41i (the uppermost switch element 44 in FIG. 5) and the switch element 44 closest to the current input / output part 43b of the switch unit 42i are the positive polarity of the present invention. This corresponds to a predetermined set of switch elements in the high-voltage power supply circuit.

  The forward direction of each diode 45 is the direction from the current input / output unit 43b to the current input / output unit 43a (the direction opposite to the direction of the current flowing through each switch element 44), and hence the reference potential unit 9i to the high voltage side potential unit 10i. It is directed in the direction toward. Each of the resistors 46 has the same resistance value, and the resistance value is a relatively large resistance value (a resistance value at which a current flowing through each resistor 46 is sufficiently small).

  The drive circuit 47 includes the same number of winding transformers 48 as the number of switch elements 44. Each winding transformer 48 has a secondary winding interposed between the gate and the source of the switch element 44 (n-channel FET) corresponding to the winding transformer 48. The primary windings of these winding transformers 48 are connected in parallel between the pair of control signal input units 49a and 49b. Therefore, by inputting a rectangular wave drive signal to the control signal input sections 49a and 49b, a rectangular wave drive signal is simultaneously induced in the secondary winding of each winding transformer 48, and the drive signal is supplied to each switch. The signal is input to the gate of the element 44 at the same time. As a result, for each switch unit 41i, 42i, all the switch elements 44 included therein are turned on / off simultaneously.

  Since each winding transformer 48 outputs a drive signal (gate signal) for each switch element 44, it may be capable of passing a minute current. For this reason, each winding transformer 48 may have a small capacity.

  In this embodiment, the switch element 44 is configured by an n-channel FET. However, a p-channel FET may be used, or a switching transistor may be used.

  Supplementally, the number of switch elements 44 included in each switch unit 41i, 42i is the voltage value obtained by dividing the output voltage ebi of the i-th stage DC voltage conversion circuit 40i by the number of each switch element 44 and diode 45. It is set not to exceed the pressure resistance.

In addition, the DC voltage conversion circuits 40i (i = 2 to N) from the second stage to the Nth stage are arranged in the first high-voltage power supply circuit of the present invention by all the switch elements included in the switch unit 41i. The second switch means in the positive high voltage power supply circuit of the present invention is constituted by all the switch elements included in the switch unit 42i. Furthermore, for the first stage DC voltage converter 40 _1, the switching elements 2 and 3, the first switch means in the positive polarity high voltage power supply circuit in the present invention, together with constitute a second switching means, the switch element 2 and 3 correspond to a set of switch elements.

  In each of the DC voltage conversion circuits 40i (i = 2 to N) after the second stage described above, a positive DC voltage is provided between the low voltage side positive potential portion 12i and the reference potential portion 9i, which is the other end of the coil 5i. While applying eai (constant voltage or periodically changing DC voltage), the switch units 41i and 42i are alternately turned on and off via the corresponding drive circuits 47, thereby converting the DC voltage shown in FIG. Similarly to the circuit 1, the DC voltage conversion circuit 40i is boosted, and a positive DC voltage ebi (reference) obtained by boosting the DC voltage eai between the high-voltage side positive potential portion 10i and the reference potential portion 9i. A DC voltage at which the high-voltage side positive potential portion 10i becomes positive with respect to the potential portion 9i is generated. Here, turning on the switch unit 41i means simultaneously turning on all the switch elements 44 included in the switch unit 41i, and turning off the switch unit 41i means that the switch unit 41i is turned on. This means that all the switch elements 44 included in 41i are turned off simultaneously. The same applies to ON / OFF of the switch unit 42i.

  In this case, in a state where the switch unit 41i is off and the switch unit 42i is on, the DC voltage ebi that is the output voltage of the i-th stage DC voltage conversion circuit 40i is almost equal between both ends of the switch unit 41i. However, the voltage is divided into the number of the switch elements 44 by the resistor 46 of the switch unit 41i. Then, the divided voltage acts on the parallel circuit of each switch element 44 and diode 45 of the switch unit 41i. Similarly, in a state where the switch unit 41i is on and the switch unit 42i is off, the voltage (≈ebi) acting on both ends of the switch unit 42i is caused by the resistance 46 of the switch unit 42i. The voltage is divided into the number, and the divided voltage acts on the parallel circuit of each switch element 44 and diode 45 of the switch unit 42i.

  Accordingly, by setting the number of the switch elements 44 of each switch unit 41i, 42i as described above, the DC voltage ebi (DC voltage conversion circuit 40i between the reference potential portion 9i and the high-voltage side positive potential portion 10i is set. Even if the output voltage is relatively large, it is possible to prevent an excessive voltage exceeding the breakdown voltage from acting on each switch element 44 and diode 45. Therefore, when the breakdown voltage of each switch element 44 and diode 45 is the same as the breakdown voltage of switch elements 2 and 3 and diodes 7 and 8 of DC voltage conversion circuit 1 in FIG. The circuit 40 i can generate a higher output voltage than the DC voltage conversion circuit 1.

As shown in FIG. 4, the positive high-voltage power supply circuit 100 of this embodiment is configured by connecting these DC voltage conversion circuits 40i (i = 1 to N) in series. That is, when an arbitrary integer of n to 2 to N, the reference potential portion 9n and the low pressure side positive potential portion 12n of the n-stage DC voltage converter 40n, respectively, the n-1 stage DC voltage converter 40 _{n -1} reference potential portion 9 _n-1 and high voltage side positive potential portion 10 _n-1 are connected to the same potential. Thus, the output voltage eb _n-1 of the n-1 stage DC voltage converter 40 _n-1 is, are inputted as a DC input voltage ea _n to the n-stage DC voltage converter 40n.

In the positive polarity high-voltage power supply circuit 100 of the present embodiment configured as described above, the i-th stage DC voltage conversion circuit 40i constituting the second high-voltage power supply circuit 40i has a second output voltage ebi that increases as the value of i increases. Each switch unit 41i, 42i of each DC voltage conversion circuit 40i (i = 2 to N) after the stage is configured as described above. For this reason, it is possible to prevent an excessive voltage exceeding the withstand voltage from acting on each switch element 44 and diode 45 included in each switch unit 41i, 42i. Accordingly, it is possible to finally output a high-voltage DC voltage from the N-th stage DC voltage conversion circuit 40 _N.

In this case, the first stage DC voltage converter 40 ₁ of each DC voltage converter 40i including are both possible bidirectional power transfer is between that input and output sides, a first stage Even if the DC voltage ea ₁ input to the DC voltage conversion circuit 40 ₁ has a waveform that changes at a relatively high speed, the high-voltage DC power supply circuit 100 uses the high-voltage DC voltage eb _N that follows it with high responsiveness. Can be generated.

  Next, an embodiment of the negative high voltage power supply circuit of the present invention will be described with reference to FIG. 6 and FIG. FIG. 6 is a circuit configuration diagram of the negative high voltage power supply circuit of the present embodiment.

  Referring to FIG. 6, the negative high voltage power supply circuit 200 according to the present embodiment is configured to sequentially add a plurality (N) of DC voltage conversion circuits 50 i (i = 1, 2,..., N) (suffix i). In order) and connected in series. In the illustrated example, N = 3. Hereinafter, as in the case of the positive high-voltage power supply circuit 100, each DC voltage conversion circuit 50i may be referred to as an i-th stage DC voltage conversion circuit 50i. Further, in order to distinguish the constituent elements of each DC voltage conversion circuit 50i, a suffix “i” is added to the reference numerals of the constituent elements as necessary.

Each DC voltage conversion circuit 50i is the same as the DC voltage conversion circuit 21 shown in FIG. 3, or a part of the configuration thereof is changed. In the present embodiment, the first stage DC voltage conversion circuit 50 ₁ is the same as the DC voltage conversion circuit 21 of FIG. Therefore, the first stage DC voltage conversion circuit 50 ₁ is given the same reference numerals as those in FIG. 3 (or the reference numerals with the subscript “1” added) to the components, and the description thereof is omitted.

On the other hand, in this embodiment, the second stage DC voltage converter 50 ₂ N-th stage DC voltage converter 50 each DC voltage converter 50i to _M (i = _2~N) is of the DC voltage conversion circuit 21 The parallel circuit composed of the switch element 22 and the diode 27 and the parallel circuit composed of the switch element 23 and the diode 28 are replaced with switch units 41i and 42i, respectively. The switch units 41i and 42i have the same circuit configuration as the switch unit shown in FIG. However, in the present embodiment, each switch unit 41i, 42i is upside down from that shown in FIG. 4, and the current input / output portion 43b of the current input / output portions 43a, 43b of the switch unit 41i and the switch unit 42i The switch units 41i and 42i are connected in series by connecting the current input / output portions 43a of the current input / output portions 43a and 43b to each other. The current input / output unit 43a of the switch unit 41i and the current input / output unit 43b of the switch unit 42i are respectively used as the reference potential unit 29i and the high-voltage side potential unit 30i of the i-th stage DC voltage conversion circuit 50i. A capacitor 26i is connected in parallel with the series circuit of the units 41i and 42i. One end of the coil 25i is connected to a location between the switch unit 41i and the switch unit 42i, and the other end of the coil 25i is a low-voltage negative potential portion 32i.

  In the present embodiment, each switch element 44 of each switch unit 41i, 42i is composed of an n-channel FET. However, a p-channel FET may be used, or a switching transistor may be used.

  The number of switch elements 44 included in each switch unit 41i, 42i is such that the voltage value obtained by dividing the output voltage -ebi of the DC voltage conversion circuit 50i by the number exceeds the breakdown voltage of each switch element 44 and diode 45. It is set not to.

Supplementally, in this embodiment, the switch element in the negative high-voltage power supply circuit of the present invention is connected in series with the series circuit of the plurality of switch elements 44 of the switch unit 41i and the series circuit of the plurality of switch elements 44 of the switch unit 42i. A circuit will be constructed. Moreover, the first switch means in the negative polarity high voltage power supply circuit of the present invention is constituted by all the switch elements included in the switch unit 41i, and the negative polarity high voltage of the present invention is constituted by all the switch elements included in the switch unit 42i. The second switch means in the power supply circuit is configured. Further, the switch element 44 closest to the current input / output portion 43b of the switch unit 41i (the lowermost switch element 44 in FIG. 5) and the switch element 44 closest to the current input / output portion 43a of the switch unit 42i (the uppermost switch input in FIG. 5). The switch elements 44) correspond to a predetermined set of switch elements in the negative-polarity high-voltage power supply circuit of the present invention. Furthermore, for the first stage DC voltage converter 50 _1, the switching elements 22 and 23, first switching means in the negative polarity high voltage power supply circuit in the present invention, together with constitute a second switching means, the switch element 22 and 23 correspond to a predetermined set of switch elements.

  In each of the DC voltage conversion circuits 50i (i = 2 to N) after the second stage described above, a negative DC voltage is provided between the low-voltage side positive potential portion 32i that is the other end of the coil 25i and the reference potential portion 29i. A DC voltage conversion circuit is applied in the same manner as the DC voltage conversion circuit 21 of FIG. 3 by alternately turning on and off the switch units 41i and 42i while applying -eai (a constant voltage or a periodically changing DC voltage). 50i is boosted, and a negative DC voltage -ebi obtained by boosting the DC voltage -eai between the high voltage side negative potential part 30i and the reference potential part 29i (high voltage side with respect to the reference potential part 29i). DC voltage at which the negative potential portion 30i has a negative polarity) is generated. In addition, the meaning of ON / OFF of each switch unit 41i, 42i is the same as the case of the said positive polarity high voltage power supply circuit 100.

  In this case, by setting the number of switch elements 44 of each switch unit 41i, 42i as described above, the reference potential portion 29i and the high-voltage-side negative potential portion 30i are the same as in the case of the positive high-voltage power supply circuit 100. Even if the DC voltage -ebi (the output voltage of the DC voltage conversion circuit 50i) is relatively large, an excessive voltage exceeding the withstand voltage acts on each switch element 44 and the diode 45. Can be prevented. Therefore, when the breakdown voltage of each switch element 44 and diode 45 is the same as the breakdown voltage of switch elements 22 and 23 and diodes 27 and 28 of DC voltage conversion circuit 21 in FIG. The circuit 50 i can generate a higher output voltage than the DC voltage conversion circuit 21.

As shown in FIG. 6, the negative high voltage power supply circuit 200 of the present embodiment is configured by connecting these DC voltage conversion circuits 50i (i = 1 to N) in series. That is, the reference potential portion 9n and the low-voltage negative potential portion 32n of the n-th stage DC voltage conversion circuit 40n (n is an arbitrary integer from 2 to N) are respectively connected to the (n-1) -th stage DC voltage conversion circuit 50n _-1. The reference potential portion 29 _n-1 and the high _- voltage side negative potential portion 30 _n-1 are connected to the same potential. Thus, the output voltage-eb _n-1 of the (n-1) th stage DC voltage converter 50 _n-1 is, are inputted as a DC input voltage -ea _n to the n-stage DC voltage converter 50n .

In the negative polarity high voltage power supply circuit 200 of the present embodiment configured as described above, the i-th stage DC voltage conversion circuit 50i constituting the larger the value of the output voltage −eb i as the value of i increases. However, as in the case of the positive high-voltage power supply circuit 100, it is possible to prevent an excessive voltage exceeding the withstand voltage from acting on the switch elements 44 and the diodes 45 included in the switch units 41i and 42i. Accordingly, it is possible to finally output a high-voltage DC voltage from the N-th stage DC voltage conversion circuit 50 _N.

In addition, since each DC voltage conversion circuit 50i including the first stage DC voltage conversion circuit 50 ₁ can transmit bidirectional power between its input side and output side, the first stage DC voltage conversion circuit 50i can be used. Even if the DC voltage -ea ₁ input to the voltage conversion circuit 50 ₁ has a waveform that changes at a relatively high speed, the high-voltage DC voltage -eb _N that follows it with high response is used as a negative high-voltage power supply circuit. 200 can be generated.

In each embodiment described above, the positive or negative high voltage power supply circuit 100 or 200 has a three-stage configuration, but may have a two-stage configuration or a four-stage or more configuration. Further, the first stage DC voltage conversion circuit 40 ₁ or 50 ₁ includes only two switch elements 2, 3 or 22, 23, but the second to Nth stage DC voltage conversion circuits 40 ₂ to 40 are included. Similarly to _N or 50 ₂ to 50 _N , the above-described switch units 41 and 42 may be provided.

  Further, in each of the embodiments described above, only the positive or negative direct current high voltage is generated, but by combining the positive high voltage power circuit 100 and the negative high voltage power circuit 200, Bipolar DC high voltage may be generated. Alternatively, for example, the AC high voltage is generated by periodically changing the output voltages of the positive high-voltage power supply circuit 100 and the negative high-voltage power supply circuit 200 and switching the output voltages alternately. It is also possible to do so.

The circuit block diagram of the DC voltage conversion circuit relevant to embodiment of the positive polarity high voltage power supply circuit of this invention. The timing chart which shows the operation | movement of the switch element of the DC voltage converter circuit of FIG. The circuit block diagram of the DC voltage converter circuit relevant to embodiment of the negative polarity high voltage power supply circuit of this invention. The circuit block diagram of embodiment of the positive polarity high voltage power supply circuit of this invention. The circuit block diagram of the switch unit with which the circuit of FIG. 4 was equipped. The circuit block diagram of embodiment of the negative polarity high voltage power supply circuit of this invention.

Explanation of symbols

  2, 3, 22, 23, 44 ... switch element, 7, 8, 27, 28, 45 ... diode, 46 ... resistor, 5 (5i), 25 (25i) ... coil, 6 (6i), 26 (26i) ... Capacitors, 9 (9i), 29 (29i) ... reference potential part, 10 (10i) ... high voltage side positive potential part, 12 (12i) ... low voltage side positive potential part, 30 (30i) ... high voltage side negative potential part, 32 (32i)... Low voltage side negative potential portion, 100... Positive polarity high voltage power supply circuit, 200.

Claims (2)

A switch element circuit formed by connecting a plurality of switch elements that can be controlled on / off in series, and one end of the switch element circuit is positive with respect to the reference potential portion and the other end is positive with respect to the reference potential portion. A diode connected in parallel to each of the plurality of switch elements so that a direction from the reference potential portion toward the high voltage side positive potential portion is a forward direction, and the reference potential portion A capacitor having one end connected between a capacitor connected in parallel with the switch element circuit between the high-voltage side positive potential portion and a predetermined set of switch elements adjacent to each other in the switch element circuit The other end of the coil as a low-voltage side positive potential portion, and applying the positive DC input voltage between the low-voltage side positive potential portion and the reference potential portion, the predetermined set of switches Elemental The first switch means composed of all the switch elements located closer to the reference potential portion than the location and the second switch means composed of all switch elements located closer to the high-voltage side positive potential portion than the location. A DC voltage conversion circuit that performs a boosting operation to generate a positive DC voltage obtained by boosting the DC input voltage between the high-voltage side positive potential portion and the reference potential portion is turned on and off. (N: an integer greater than or equal to 2)
One of the N DC voltage conversion circuits is a first stage DC voltage conversion circuit, and each of the other DC voltage conversion circuits is an nth stage DC voltage conversion circuit (n: integer from 2 to N). In the N DC voltage conversion circuits, the reference potential portions of the N DC voltage conversion circuits have the same potential, and the low voltage side positive potential portion of the nth DC voltage conversion circuit is the high voltage of the (n-1) th DC voltage conversion circuit. Connected to the same potential as the side positive potential part,
First switch means and second switch of each DC voltage conversion circuit from at least a predetermined k-th stage DC voltage conversion circuit (k is a predetermined integer of 1 or more and N or less) to the N-th stage DC voltage conversion circuit A positive-voltage high-voltage power supply circuit comprising a plurality of the switch elements constituting each means and a resistor connected in parallel to each switch element of each switch means. A switch element circuit formed by connecting a plurality of switch elements that can be controlled on and off in series, and one end of both ends of the switch element circuit is negative with respect to the reference potential section and the other end is negative with respect to the reference potential section A diode connected in parallel to each of the plurality of switch elements so that a direction from the high voltage negative potential portion toward the reference potential portion is a forward direction, and the reference potential portion And a capacitor having one end connected to a location between a capacitor connected in parallel with the switch element circuit between the high voltage side negative potential portion and a predetermined set of switch elements adjacent to each other in the switch element circuit The other end of the coil as a low-voltage negative potential portion, and applying a negative DC input voltage between the low-voltage negative potential portion and the reference potential portion, the predetermined set of switches Elemental The first switch means composed of all the switch elements located closer to the reference potential portion than the location and the second switch means composed of all switch elements located closer to the high-voltage-side negative potential portion than the location. A DC voltage conversion circuit that performs a boosting operation for generating a negative DC voltage obtained by boosting the DC input voltage between the high-voltage-side negative potential portion and a reference potential portion is turned on and off. (N: an integer greater than or equal to 2)
One of the N DC voltage conversion circuits is a first stage DC voltage conversion circuit, and each of the other DC voltage conversion circuits is an nth stage DC voltage conversion circuit (n: integer from 2 to N). In the N DC voltage conversion circuits, the reference potential portions of the N DC voltage conversion circuits have the same potential, and the low voltage side positive potential portion of the nth DC voltage conversion circuit is the high voltage of the (n-1) th DC voltage conversion circuit. Connected to the same potential as the side positive potential part,
First switch means and second switch of each DC voltage conversion circuit from at least a predetermined k-th stage DC voltage conversion circuit (k is a predetermined integer of 1 or more and N or less) to the N-th stage DC voltage conversion circuit A negative-voltage high-voltage power supply circuit comprising a plurality of the switch elements constituting each means and a resistor connected in parallel to each switch element of each switch means.

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