JP4262464B2 - High output high voltage power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-output high-voltage power supply, and more particularly to a technique for removing harmonics from a high-output high-voltage power supply used in an electron beam drawing apparatus or the like.
[0002]
[Prior art]
As a drawing means for a photomask of an integrated circuit, an apparatus using an electron beam is known, and this type of electron beam drawing apparatus uses a high-output high-voltage power supply for accelerating the electron beam. It has been.
[0003]
As such a power source, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-351799, a combination of a Cockcroft-Walton type multiplication circuit and a step-up transformer is generally used. Yes.
[0004]
In this case, a PWM (Pulse Width Modulation) method is generally employed to control the output voltage, but it is not suitable for this type of high voltage power supply that requires high stability.
[0005]
Therefore, conventionally, the output voltage has been stabilized by the method shown in FIG. The high-output high-voltage power source shown in FIG. 1 includes a Cockcroft-Wolton type multiplier circuit 1 and a step-up transformer 2, and a DC blocking capacitor C is provided on the input side of the step-up transformer 2. A half-bridge type inverter circuit 3 is connected to the inverter circuit 3, and a variable output DC power source 4 is connected to the inverter circuit 3.
[0006]
The output side of the Cockcroft-Walton type multiplier circuit 1 is connected to an electron gun (not shown), and a resistor voltage divider 5 in which a plurality of resistors are connected in series is connected in parallel. A feedback control circuit 6 of the variable output DC power supply 4 is connected to the resistance voltage divider 5.
[0007]
In the power source configured as described above, in order to control the DC voltage supplied to the inverter circuit 3 and stabilize the output voltage, the inverter circuit 3 is supplied with a pulsed control voltage as shown in FIG. I was typing.
[0008]
On the other hand, the step-up transformer 2 is driven by a parallel resonance circuit of the inherent excitation inductance of the step-up transformer 2 and the distributed capacity of the Cockcroft-Walton type multiplier circuit 1, and the step-up transformer 2 and the inverter circuit 4, a harmonic filter 7 composed of a plurality of capacitors and inductors is interposed in order to remove the third, fifth, seventh,... Harmonics as shown in FIG.
[0009]
However, the conventional high-output high-voltage power supply having such a configuration has technical problems described below.
[0010]
[Problems to be solved by the invention]
That is, the conventional high main power high voltage power source shown in FIGS. 3 and 4 requires a harmonic filter 7 for removing harmonics. If such a filter is provided, an installation place is required. Since the resonance point of each harmonic has to be set, adjustment is troublesome.
[0011]
The present invention has been made in view of such conventional problems, and its object is to provide a high-output high-voltage power supply that does not require a harmonic filter by eliminating the generation of harmonics. There is to do.
[0012]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a Cockcroft-Wolton type multiplier circuit, a step-up transformer connected to the output side of the multiplier circuit, and a DC component blocking on the input side of the step-up transformer. And a variable output DC power source connected to the input side of the inverter circuit, and a pulsed control voltage whose direction is reversed every predetermined cycle is input to the inverter. In the high-output high-voltage power source, the step-up transformer constituted by a parallel resonance of the distributed capacity of the secondary coil of the step-up transformer and the distributed capacity of the multiplication circuit and the exciting inductance of the step-up transformer And the multiplication circuit, the control is performed so that the time integral value of the input signal matches the time integral value of the output signal. A high output high voltage power supply for setting the pressure, the alignment is to the control voltage, with a predetermined supply stop time, coincides with the time integration value of the input signal, a time integral value of the output signal I tried to make it .
[0013]
According to the high-output high-voltage power supply configured as described above, the step is configured by the parallel resonance of the distributed capacity of the secondary coil of the step-up transformer and the distributed capacity of the multiplication circuit and the exciting inductance of the step-up transformer. The control voltage is set so that the time integral value of the input signal matches the time integral value of the output signal in the equivalent circuit of the up transformer and the multiplier circuit, so that the magnetic energy in the equivalent circuit matches. Therefore, a harmonic filter for removing harmonics is required.
[0014]
When the harmonic filter is unnecessary, it is not necessary to set a resonance point or troublesome adjustment, and it is not necessary to secure an installation place.
[0016]
The input signal is a rectangular pulse signal, the output signal is a sine wave signal, and the stop time is 0.367 when the direction is reversed every 180 °. It can be a percentage.
[0017]
The stop time can be set to a ratio of 0.367 when the direction is reversed every 180 °.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of a high-output high-voltage power supply according to the present invention.
[0019]
The high-output high-voltage power supply of this embodiment includes a Cockcroft-Wolton type multiplier circuit 1 in which a capacitor and a diode are combined and a step-up transformer 2 in the same manner as this type of conventional power supply. A half-bridge type inverter circuit 3 is connected to the input side of the transformer 2 via a DC blocking capacitor C, and a variable output DC power source 4 is connected to the inverter circuit 3.
[0020]
The output side of the Cockcroft-Walton type multiplier circuit 1 is connected to an electron gun (not shown), and a resistor voltage divider 5 in which a plurality of resistors are connected in series is connected in parallel. The resistance voltage divider 5 is connected with a feedback control circuit 6 of the variable output DC power supply 4.
[0021]
In the power supply configured as described above, a pulse voltage is input to the inverter circuit 3 in order to control the DC voltage supplied to the inverter circuit 3 and stabilize the output voltage. The basic configuration as a high-output high-voltage power supply and the control method of the sumverter circuit 3 are substantially the same as those of the conventional power supply shown in FIG.
[0022]
However, the high-output high-voltage power supply of this embodiment has the following remarkable features. That is, in the power source shown in FIG. 3, the step-up transformer 2 is used in a parallel resonance state of the inherent excitation inductance of the step-up transformer 2 and the distributed capacitance of the Cockcroft-Walton type multiplier circuit 1. .
[0023]
An equivalent circuit at this time is shown in FIG. In the figure, an input signal of the AC signal A input from the inverter circuit 3, L _l1 is the primary self-inductor Chi chest of step-up transformer 3, L _l2 is, second the transformer 2 Secondary side self-inductance.
[0024]
Further, the mutual inductance L _ex is the transformer 2, C _s is the sum of the distributed capacitance of the secondary coil of the transformer 2 of the Cockcroft-Walton type multiplier circuit 1. In this equivalent circuit, a parallel resonant circuit is configured by L _ex and C _s .
[0025]
In such an equivalent circuit, in the conventional high output high voltage circuit, as shown in FIG. 3, a pulse-like signal is inputted to the inverter circuit 3, and the inverter circuit 3 shows in FIG. 2 (A). The pulse signal A that switches between positive and negative every 180 ° (π) is input.
[0026]
In this case, a sinusoidal output signal C as shown in FIG. 2C is sent to the output side. However, when the input / output state is in such a relationship, according to the knowledge of the present inventors, a mismatch occurs in electromagnetic energy between the input and output, and as a result, on the input side of the equivalent circuit. 3rd, 5th and 7th harmonics were found to be generated.
[0027]
In the conventional power supply of this type, a harmonic filter 7 as shown in FIG. 4 is interposed in order to remove such third, fifth, seventh,... Harmonics. There are inconveniences as mentioned above.
[0028]
Therefore, in this embodiment, in the equivalent circuit shown in FIG. 1, the inverter circuit is configured so that the time integration value of the input signal (voltage or current) matches the time integration value of the output signal (voltage or output current). A control voltage of 3 was set.
[0029]
More specifically, the time integral value of the input or output signal corresponds to the area of each signal as shown by hatching in FIG. That is, the rectangular wave shown in FIG. 2A is a conventional output signal, and FIG. 2C is the waveform of the output signal.
[0030]
In this case, if the signal size is the same, the square wave has a larger area, that is, the time integration value, than the sine wave, and this difference seems to have caused the magnetic energy mismatch. It is.
[0031]
In the present embodiment, in order to eliminate such a difference in the time integration value, a predetermined pause time is provided in the input signal so that the time integration values match each other. The difference in area between the rectangular wave and the sine wave is 2 / π = 0.537 when the rectangular wave is set to 1. Therefore, the supply is stopped by 1−0.637 = 0.367 during this pause time. (See FIG. 2B).
[0032]
In this way, when the time integration values of the input signal and the output signal are matched, in the equivalent circuit shown in FIG. 1, the magnetic energy between the input and output can be matched, and the third, fifth, fifth, 7: Harmonics are not generated.
[0033]
Since the output of the inverter circuit 3 is proportional to the control voltage, in order to input an output signal as shown in FIG. 2B to the equivalent circuit, an input signal having a similar waveform is controlled by the inverter circuit 3. What is necessary is just a voltage.
[0034]
Now, according to the high-output high-voltage power supply configured as described above, the distributed capacity of the secondary coil of the step-up transformer 2 and the distributed capacity of the multiplier circuit 1 and the exciting inductance of the step-up transformer 2 are parallel. The control voltage of the inverter circuit 3 is set so that the time integral value of the input signal and the time integral value of the output signal are matched in an equivalent circuit of the step-up transformer 2 configured by resonance and the multiplier circuit 1. Therefore, the magnetic energy in the equivalent circuit is matched, and the third, fifth, seventh,... Harmonics are not generated, and as a result, a harmonic filter for removing the harmonics is required.
[0035]
When the harmonic filter is unnecessary, it is not necessary to set a resonance point or troublesome adjustment, and it is not necessary to secure an installation place.
[0036]
【The invention's effect】
As described above in detail, according to the high-output high-voltage power supply according to the present invention, it is possible to eliminate a harmonic filter by eliminating the generation of harmonics.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an equivalent circuit showing one embodiment of a high-output high-voltage power supply according to the present invention.
2 is an explanatory diagram of input and output signal waveforms of the equivalent circuit shown in FIG. 1; FIG.
FIG. 3 is a circuit diagram of a basic configuration of a high-output high-voltage power supply according to the present invention.
FIG. 4 is an explanatory diagram of a harmonic filter used in a conventional power supply.
[Explanation of symbols]
1 Cockcroft-Walton type multiplier 2 Step-up transformer 3 Inverter circuit 4 Variable output DC power supply

Claims (2)

Cockcroft-Wolton type multiplier, step-up transformer connected to the output side of the multiplier, and inverter circuit connected to the input side of the step-up transformer via a DC blocking capacitor A high-output high-voltage power supply that includes a variable output DC power supply connected to the input side of the inverter circuit, and inputs a pulsed control voltage whose direction is reversed every predetermined cycle to the inverter.
Equivalent of the step-up transformer and the multiplier circuit configured by the parallel resonance of the distributed capacity of the secondary coil of the step-up transformer and the distributed capacity of the multiplier circuit and the exciting inductance of the step-up transformer A high-output high-voltage power supply that sets the control voltage so that the time integral value of the input signal matches the time integral value of the output signal in the circuit,
The high-output high-voltage power supply characterized in that the matching is performed by providing a predetermined supply stop time for the control voltage so that the time integral value of the input signal matches the time integral value of the output signal . The input signal is a rectangular pulse signal, the output signal is a sine wave signal,
2. The high-output high-voltage power supply according to claim 1, wherein the stop time is set to a ratio of 0.367 when the direction is reversed every 180 degrees.

Images