JP3328089B2 - Switching device control device and control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate control device and a control method for a switching element having a field emission cold cathode.

[0002]

2. Description of the Related Art In recent years, field emission cold cathodes have been actively developed by applying advanced silicon semiconductor processing techniques. Field emission cold cathodes have various application fields such as display devices, high-speed microwave devices, electron beam devices, and power devices.

As one application of the field emission type cold cathode to a power device, a vacuum microswitching device having a configuration similar to a triode has been considered. Since this element is a high-voltage element, a high-voltage switching element obtained by connecting tens of thyristors or GTOs each having a withstand voltage of several KV in series at present can be manufactured with one element. Therefore, it is very suitable as a switching element such as a converter used for high-voltage DC power transmission.

FIG. 3 is a schematic view of a vacuum microswitching device. In FIG. 3, the vacuum microswitching element 1 has an anode electrode 2, an emitter electrode 3, and a gate electrode 4.

[0005] The gate power supply 5 causes the gate pulse generator 6 to generate a gate pulse as a power supply for the gate pulse generator 6. The main circuit power supply 7 and main circuit loads 8a and 8b are connected to the switching elements.

Next, the operation principle of the switching element will be described. By applying a positive voltage of a few volts to the gate electrode 4 with respect to the emitter electrode 3, a very high electric field is generated at the apex of the emitter electrode cone. Due to this high electric field, electrons are extracted at the apex of the conical portion of the emitter electrode by a tunnel effect, and the electrons emitted from the emitter electrode 3 reach the anode electrode 2 so that the main circuit load 8a,
8b can be controlled. The main circuit loads 8a,
The amount of current flowing through 8 b is controlled by the amount of electrons described above, and the amount of electrons is controlled by the potential of the gate electrode 4.

[0007]

However, in the above switching element, in order for the electrons emitted from the emitter electrode to reach the anode electrode, the gate potential must be lower than the anode potential.

This is because if the gate potential is higher than the anode potential, electrons emitted from the emitter electrode do not go to the anode electrode but reach the gate electrode, so that the main circuit current stops flowing. However, the main circuit power supply fluctuates and the main circuit load also fluctuates, so that the anode potential fluctuates without being constant. However, conventional gate control ignores the anode potential and controls the gate potential, so that the gate potential may be higher than the anode potential, and electrons emitted from the emitter electrode reach the gate electrode without going to the anode electrode. As a result, problems such as the main circuit current not flowing or the gate electrode being destroyed occurred.

Therefore, the present invention provides a gate control device and a control method for a switching element using a field emission type cold cathode in which electrons emitted from an emitter electrode surely reach an anode electrode. The purpose is to:

[0010]

According to a first aspect of the present invention, there is provided a switching device control apparatus for controlling a switching element, comprising: a first electrode for emitting electrons; and a first electrode for emitting electrons to the first electrode. In a switching device control device using a field emission type cold cathode having a second electrode for promoting and a third electrode for capturing electrons emitted from the first electrode, the second electrode and the third electrode Comparing means for comparing the potential with the electrode; and generating a drive signal for providing a drive signal to the second electrode when the output of the comparing means is higher than the potential of the third electrode. Means.

In the control device for a switching element according to a second aspect of the present invention, the first electrode for emitting electrons, the second electrode for prompting the first electrode to emit electrons, and the emission of the first electrode. A switching device control device using a field emission cold cathode having a third electrode for capturing the captured electrons,
Measuring means for measuring the potential of the third electrode, voltage control means serving as a voltage source having a potential lower than the potential of the third electrode according to the output of the measuring means, and a voltage source And a drive signal generating means for outputting a drive signal to the second electrode.

[0012]

[0013]

[0014]

In the control device for a switching element according to the first aspect of the present invention, the comparing means for comparing the potentials of the second electrode and the third electrode is such that the potential of the third electrode is higher than the potential of the second electrode. When it is determined that the voltage is high, a drive signal is given to the second electrode by the drive signal generation means.

In the control device for a switching element according to a second aspect of the present invention, the voltage control means is a voltage source having a lower potential according to the output of the measuring means for measuring the potential of the third electrode. Since the drive signal generating means uses the voltage control means as a voltage source, the potential of the second electrode is lower than the potential of the third electrode.

[0016]

[0017]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a first embodiment of the present invention. FIG.
1, the vacuum microswitching element 1 has an anode electrode 2, an emitter electrode 3, and a gate electrode 4.

The switching element 1 is connected to a gate pulse generator 6 for generating a gate pulse using the gate power supply 5 as a voltage source, a main circuit power supply 7, and main circuit loads 8a and 8b.

The voltage measuring device 9 measures the potential of the anode electrode, and the voltage measuring device 10 measures the potential of the gate electrode. The comparator 11 is based on the measurement results of the voltage measurement device 9 and the voltage measurement device 10,
When the output of the voltmeter 9 is greater than the output of the voltmeter 10, “1” is output. When the output of the voltmeter 9 is smaller than the output of the voltmeter 10, “0” is output.

The switch 12 is closed when the output of the comparator 11 is "1" and is opened when the output of the comparator 11 is "0". Next, the control operation of this switching element will be described.

The potential of the anode electrode is measured by the voltmeter 9, and the potential of the gate electrode is measured by the voltmeter 10. The output of the voltage measuring device 9 and the output of the voltage measuring device 10 are input to the comparator 11. The comparator 11 compares the output of the voltage measuring device 9 with the output of the voltage measuring device 10, and when the output of the voltage measuring device 9 is larger than the output of the voltage measuring device 10, that is, when the potential of the anode electrode is equal to the potential of the gate electrode. When it is higher, it outputs "1" and the switch 12 receives this signal and is closed. Therefore, the gate pulse generator 6 is connected to the gate electrode.
Is sent.

When the output of the voltage measuring device 9 is smaller than the output of the voltage measuring device 10, that is, when the potential of the anode electrode is smaller than the potential of the gate electrode, the comparator 11 outputs "0". Opened in response to this signal. Therefore, the gate pulse from the gate pulse generator 6 is not sent to the gate electrode.

Therefore, when the potential of the anode electrode is lower than the potential of the gate electrode, a gate pulse is not sent to the gate electrode, and electrons emitted from the emitter electrode are not sent to the gate electrode.

FIG. 2 is a schematic diagram showing a second embodiment of the present invention. In FIG. 2, the vacuum micro-switching element 1 has an anode electrode 2, an emitter electrode 3, and a gate electrode 4. 7 is a main circuit power supply, and 8a and 8b are main circuit loads.

The voltage measuring device 9 measures the potential of the anode electrode, the amplification gate power supply 13 has an amplification function with a gain of 1 or less, and the gate pulse generator 6 uses the amplification gate power supply 13 as a power supply to supply gate pulses. Generate.

Next, the control operation of the switching element will be described. First, the potential of the anode electrode is measured by the voltage measuring device 9, and its output is one input of the amplification gate power supply 13, and the other input is connected to the emitter electrode. Since the gain of the amplification gate power supply 13 is 1 or less,
The gate power of the gate pulse generator 6 is lower than the potential of the anode electrode. Therefore, the potential of the gate electrode becomes lower than the potential of the anode electrode.

Therefore, since the potential of the gate electrode is always lower than the potential of the anode electrode, the electrons emitted from the emitter electrode are not sent to the gate electrode, and reach the anode electrode without fail.

[0028]

As described above, in the switching device control device according to the first aspect of the present invention, the second electrode is connected to the second electrode only when the potential of the third electrode is higher than the potential of the second electrode. Since the driving signal is supplied, when the potential of the third electrode is lower than the potential of the second electrode, the driving signal is not supplied to the second electrode, and electrons emitted from the first electrode are discharged from the second electrode. Is not sent to the third electrode, so that the electrons emitted from the first electrode surely reach the third electrode.

In the control device for a switching element according to a second aspect of the present invention, the potential of the second electrode is controlled so that the potential of the second electrode is lower than the potential of the third electrode. Since the electrons emitted from the first electrode are not sent to the second electrode, the electrons emitted from the first electrode reliably reach the third electrode.

[0030]

[0031]

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a conventional vacuum micro-switching device control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum micro switching element 2 ... Anode electrode 3 ... Emitter electrode 4 ... Gate electrode 5 ... Gate power supply 6 ... Gate pulse generator 9,10 ... Voltage measuring instrument 11 ... Comparator 12 ... Switch 13 ... Amplification gate power supply

────────────────────────────────────────────────── ─── Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 1/304 H01J 19/00-21/36 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. An electric field having a first electrode for emitting electrons, a second electrode for promoting emission of electrons to the first electrode, and a third electrode for capturing electrons emitted from the first electrode. In a control device for a switching element using an emission type cold cathode, comparing means for comparing the potential of the second electrode with the potential of the third electrode, and the output of the comparing means is such that the third electrode is connected to the third electrode. A driving signal generating means for supplying a driving signal to the second electrode when the potential is higher than that of the second electrode. 2. An electric field having a first electrode for emitting electrons, a second electrode for prompting the first electrode to emit electrons, and a third electrode for capturing electrons emitted by the first electrode. In a control device for a switching element using an emission type cold cathode, a measuring means for measuring the potential of the third electrode, and a voltage source having a potential lower than the potential of the third electrode in accordance with an output of the measuring means And a drive signal generating means for outputting a drive signal to the second electrode using the voltage control means as a voltage source.