JPH05136669A - High voltage switch device - Google Patents

Abstract

PURPOSE:To provide the high voltage switch device with simple configuration. CONSTITUTION:A 1st diode 31, a capacitor 32, a reactor 34, and a 2nd diode 35 are provided in series between a drain D and a gate G of each of FETs 9 connected in series. A 1st resistor 33 is connected in parallel with the 1st capacitor 32, a 3rd diode 36 is connected between a source S and a connecting point of the capacitor 32 and the reactor 34 and a 2nd resistor 37 is connected between the gate and the source. One FET 9 is driven by an external oscillator 38 to turn ON/OFF the entire circuit. Thus, each FET is connected by using passive elements simply and the operation is made stable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage switch device used in a pulse generator for pulse lasers and the like.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing a pulse generator for a pulse laser using a conventional copper vapor laser described in, for example, Japanese Patent Application Nos. 2-32741 and 2-34252. In FIG. 1, 1 is a high-voltage power supply, 2 is a charging reactor connected to the high-voltage power supply 1, 3 is a charging diode connected in series with the charging reactor 2, 4 is a charging diode connected in series with the charging diode 3. Condenser, 9
Is a high-speed switching element composed of FET (field-effect transistor), etc., 8 is a switching circuit composed of a series-parallel circuit of a large number of high-speed switching elements 9, and is connected between the charging diode 3 and the high-voltage power supply 1. ..

A reverse current suppressing element 10 is connected in series with the capacitor 4 and is composed of a series-parallel circuit of a plurality of diodes or a plurality of magnetic saturation elements. Reference numeral 11 is a bypass resistor connected in parallel to the reverse current suppressing element 10, 7 is a laser discharge tube connected between the reverse current suppressing element 10 and the high-voltage power supply 1, and 5 is a charging connected in parallel to the laser discharge tube 7. It is resistance.

Reference numeral 12 is a gate circuit for driving the switch circuit 8, and a common gate terminal G of each parallel circuit stage of the high-speed switch elements 9 such as FETs forming the switch circuit 8.
And a common source terminal S, and a gate terminal G
Is configured to apply a conduction signal to.

Reference numeral 13 denotes an optical oscillator for generating an optical pulse, and 14
Is an optical pulse generated by the optical oscillator 13 for each gate circuit 12
It is an optical fiber for giving to the photoelectric conversion element inside.

Reference numeral 15 is a gate power supply circuit for supplying a power supply voltage to the gate circuit 12, and 16 is a gate power supply line for transmitting the power supply voltage.

FIG. 6 shows the structure of the gate circuit 12, 17 is a photoelectric conversion element for converting the optical pulse transmitted through the optical fiber 14 into an electrical pulse signal, and 18
Is a bias resistor connected to the output side of the photoelectric conversion element 17, and 19 is a buffer for shaping the pulse signal output from the photoelectric conversion element 17 into a conduction signal and adding it to the gate terminal G. The source terminal S is grounded. Reference numeral 20 is a connector connected to the gate power supply line 16.

FIG. 7 shows the structure of the optical oscillator 13.
Reference numeral 21 is an astable multivibrator that generates a repetitive pulse signal of a predetermined cycle, 22 is a differentiation circuit that differentiates the pulse signal, 23 is a buffer that shapes the differential pulse of the differentiation circuit 22 into a narrow pulse signal, 24 Is an electro-optical conversion element that converts the pulse signal from the buffer 23 into an optical pulse and sends it to the optical fiber 14.

FIG. 8 shows the structure of the gate power supply circuit 15. 25 is an AC power supply, 26 is an insulating transformer to which an AC voltage of the AC power supply 25 is applied, and 27 is a plurality of secondary windings of the insulating transformer 26. It is a rectifier circuit that rectifies and smoothes the generated voltage and sends it to the gate power supply line 16.

Next, the operation will be described. In FIG. 5, the high voltage is slowly charged from the high voltage power supply 1 to the capacitor 4 through the charging reactor 2, the charging diode 3, the bypass resistor 11 and the charging resistor 5. Next, when the switch circuit 8 is turned on by the turn-on signal of the gate circuit 12, the high voltage of the capacitor 4 applies a pulse voltage of several hundred nanoseconds to the laser discharge tube 7 via the reverse current suppressing element 10. As a result, the laser discharge tube 7 is discharged, and its discharge current i _x flows through the path of the capacitor 4, the switch circuit 8, the laser discharge tube 7, the reverse current suppressing element 10 and the capacitor 4. At this time, the reverse current suppressing element 10 suppresses the reverse current of the oscillating current due to the inductance of the circuit.

In the optical oscillator 13 of FIG. 7, the repetitive pulse signal output from the astable multivibrator 21 is differentiated by the differentiating circuit 22. The differential pulse is waveform-shaped by the buffer 23 to become a narrow pulse signal.

This pulse signal is converted into an optical pulse by the electro-optical conversion element 24, and this optical pulse is sent to the gate circuit 12 through the optical fiber 14.

In the gate circuit 12 of FIG. 6, the optical pulse sent through the optical fiber 14 is converted into an electric pulse signal by the photoelectric conversion element 17. This pulse signal is waveform-shaped by the buffer 19 so that it is added to the common gate terminal G of each FET parallel circuit stage of the switch circuit 8 as a conduction signal composed of a pulse signal equivalent to the narrow pulse signal, and each FET is turned on. By making it conductive,
The entire switch circuit 8 is made conductive.

In the gate power supply circuit 15 of FIG. 8, the AC voltage of the AC power supply 25 becomes a DC voltage in each rectifying circuit 27 via the insulating transformer 26. This DC voltage is supplied as a power supply voltage to the connector 20 of each gate circuit 12 via the gate power supply line 16.

[0015]

Since the switch circuit 8 used in the pulse generator for the conventional pulse laser is composed of a series-parallel circuit of a large number of high-speed switching elements 9 as described above, the series-parallel circuit of this series-parallel circuit is used. A gate circuit 12 is required for each of the parallel circuit stages, and a gate power supply circuit 15 for supplying power to each gate circuit 12.
Furthermore, the optical oscillator 13 requires as many optical fibers 14 as the number of parallel circuit stages, and the number of component configurations is large and complicated. Further, since the gate circuit 12 is composed of active components such as the buffer 19 and the photoelectric conversion element 17, there is a problem that operation timing shift may occur due to a difference in characteristics.

The present invention has been made in order to solve the above-mentioned problems, and by configuring the gate circuit with almost passive components, there is little possibility of operation timing deviation due to the difference in characteristics, and the optical It is an object of the present invention to obtain a high-voltage switch device that does not require a fiber or a gate power supply circuit.

[0017]

A high-voltage switching device according to the invention of claim 1 comprises a high-speed switching element, for example, a series or series-parallel connection of FETs, and an FE of one series circuit.
The drain terminal of T is connected to the gate terminal of the FET through the first diode, the capacitor, the reactor, and the second diode, and the first resistor for discharging is connected to both ends of the first capacitor. A third diode having a cathode connected to the connection point of the capacitor and an anode connected to the source terminal of the FET, and a second resistor provided between the gate terminal and the source terminal of the FET, and One FET of the series circuit is ON / OFF controlled.

According to a second aspect of the present invention, in the high voltage switching device, a speed-up capacitor and a primary winding of a transformer are connected in series between both ends of the FET, and the secondary side output voltage of the transformer is passed through a diode. It is designed to be added to the gate terminal.

[0019]

The high-voltage switch device according to the invention of claim 1 is
The whole is turned on / off by driving and controlling only one FET of the series circuit or the FET connected in parallel with this FET.
Therefore, the gate circuit, the optical oscillator, the gate power supply circuit, their wiring, etc. are unnecessary.

In the high voltage switching device according to the second aspect of the present invention, the voltage obtained from the secondary side of the transformer increases the gate voltage by the speed-up capacitor when the FET is turned on, thereby increasing the switching speed.

[0021]

EXAMPLES Example 1. An embodiment of the invention of claim 1 will be described below with reference to the drawings. In FIG. 1, reference numeral 30 indicates the high-voltage switch device as a whole. 9 is a high-speed switching element,
In this embodiment, FET 9 is used. Further, in this embodiment, for simplicity, the case where four FETs 9 are connected in series is shown.

Reference numerals 31, 32, 34 and 35 denote a first diode and a capacitor connected in series between a drain terminal D at one end of the FET 9 and a gate terminal G as a control terminal.
Reactor, second diode. 33 is a first resistor for discharging connected in parallel to the capacitor 22, 37 is a second resistor connected between the gate terminal G and the source terminal S at the other end of the FET 9, and 36 is a third diode. The cathode is connected to the connection point of the capacitor 32, the first resistor 33 and the reactor 34, and the anode is connected to the source terminal S.

An external oscillator 38 generates a pulse for driving the FET 9 at the bottom. Here, the time constant determined by the first resistor 33 and the capacitor 32 is set to be sufficiently longer than the repetition period driven by the external oscillator 38.

Next, the operation will be described. Now V at point a
It is assumed that the voltage of ₀ is applied and the voltage is evenly shared among the FETs 9. In this state, almost V _0/4 of the voltage being charged across the capacitor 32 of each stage. From this state, an external oscillator 38 is used to
Assume that T9 is conducting. At this time, it operates as shown in FIG. That is, when the lowermost FET 9 is turned on at time t ₀ , the voltage v ₂ applied to each upper FET 9 tends to increase by 1/3 of the lowering of the lowermost voltage v ₁ . As a result, the i ₁ current flows as shown in FIGS. 1 and 2, and the gate voltage v _G of each FET 9 is increased as shown in FIG. When the gate voltage v _G reaches the threshold voltage Vth,
Each upper FET 9 will start conduction.

Next, since the accumulated electromagnetic energy in the current i ₁ is the reactor 34, after the voltage rise of v ₂ is also stopped, it continued charging of the gate by a loop W shown in FIG. 1, sufficient Raise to the gate voltage v _G. When the gate voltage v _G reaches the maximum value, the second diode 35 prevents backflow, so that the gate voltage v _G is discharged with a time constant determined by the gate capacitance and the gate resistance 37, and eventually returns to zero. As a result, all the FETs 9 are turned off, and the state of waiting for the next operation is again set.

Example 2. FIG. 3 shows an embodiment of the invention of claim 2 in which the switching speed of the FET 9 is increased. In FIG. 3, 39 is a speed-up capacitor connected to the drain terminal D, 40 is a transformer whose primary winding is connected in series with the capacitor 39 and is connected to the source terminal S, 41 is a speed-up voltage transformer 40 Is a fourth diode that is supplied from the secondary winding to the gate terminal G.

Next, the operation will be described. The electric charge stored in the speed-up capacitor 39 is O of the FET 9.
It is supplied to the gate terminal G from the secondary side of the transformer 40 through the fourth diode 41 together with N. This supply further increases the rising speed of the gate voltage v _G ,
Very fast switching speeds are obtained.

Example 3. FIG. 4 shows an embodiment in which a large number of FETs 9 are connected in series and parallel.
Is supplied to each FET 9 connected in parallel through.

[0029]

As described above, according to the first aspect of the invention, one of the series circuits of the high-speed switching elements is used for drive control, and the other high-speed switching elements include diodes, resistors, Since the circuit composed of capacitors, reactors, etc. is connected, the conventional gate circuit,
The optical oscillator, the gate power supply circuit, and the wiring such as the optical fiber between them can all be omitted, and therefore, the number of parts can be greatly reduced, and stable operation can be obtained with a simple configuration. ..

According to the second aspect of the invention, since the speed-up capacitor and the transformer are connected to the high-speed switching element, the switching speed can be increased.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a high-voltage switch device according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of the device.

FIG. 3 is a configuration diagram of a high voltage switch device according to an embodiment of the invention of claim 2;

FIG. 4 is a configuration diagram showing another embodiment of the same device.

FIG. 5 is a configuration diagram of a conventional pulse generator for a pulse laser.

FIG. 6 is a configuration diagram of a gate circuit in the device.

FIG. 7 is a configuration diagram of an optical oscillator in the same device.

FIG. 8 is a configuration diagram of a gate power supply circuit in the device.

[Explanation of symbols]

 9 High-speed switch element 31 1st diode 32 Capacitor 33 1st resistance 34 Reactor 35 2nd diode 36 3rd diode 37 2nd resistance 39 Speedup capacitor 40 Transformer 41 4th diode

Claims (2)

[Claims] 1. A series circuit of a plurality of high-speed switching elements or a series-parallel circuit in which a plurality of the series circuits are connected in parallel,
A first diode provided in series between one end of the other high-speed switching element other than one high-speed switching element of one series circuit and a control terminal of the high-speed switching element,
A capacitor, a reactor and a second diode, a first resistor connected in parallel with the capacitor, a second resistor connected between the other end of the other high speed switching element and the control terminal, A high-voltage switch device comprising a third diode having a cathode connected to a connection point between a capacitor and the reactor and an anode connected to the other end. 2. A speed-up capacitor and a transformer 1 between one end and the other end of the other high-speed switching element.
A secondary winding voltage is connected in series with the secondary winding, and the secondary side voltage of the transformer is controlled through a fourth diode to a control terminal of the other high speed switching element or a high speed switching element connected in parallel with the other high speed switching element. The high-voltage switch device according to claim 1, wherein the high-voltage switch device is supplied to a terminal.