JP2002026706A - High-voltage switching unit and pulse generator employing the high-voltage switching unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-voltage switch unit, consisting of series connection of high-voltage switch circuits where a sufficiently constant gate voltage is applied to high-speed switching elements of each high-voltage switching circuit, each high-speed switching element which realizes switching with a high repetitive frequency, and a fault in each high-voltage switching circuit can be detected and to provide a pulse generator employing the high-voltage switching unit. SOLUTION: Forced discharge circuits G1-Gn, forcibly discharge electric charges in main high-speed switch elements IGBT1-IGBTn, and voltages VJ1-VJn at connection sections J1-Jn and gate voltages VK1-VKn of 2nd NMOS transistors TRs QB1-QBn are also discharged within a time which depends on pulse width setting resistors RF1-RFn. Moreover, the high-voltage switching unit is provided with fault detection circuits UD1-UDn, to detect destruction of the main high- speed switch elements IGBT1-IGBTn.

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 comprising a circuit using a semiconductor high voltage switch, and a high voltage pulse generator using the high voltage switch device.

[0002]

2. Description of the Related Art FIG. 8 is a circuit diagram showing an example of a high-voltage switch device used in a conventional high-voltage pulse generator.
In FIG. 8, Patent Publication No. 2809913 and the article T. IE
E Japan, Vol. 117-D, No. 11 (199
7) shows the configuration of the high-voltage switch device according to 7). FIG.
In high-pressure switch device 100 is constituted by a plurality of high voltage switch circuit SCa ₁ ~SCa _n connected in series, respective high-voltage switch circuit SCa ₁ ~SCa _n is I
It is composed of a high-speed switching element 101 using a GBT, an FET or the like, and a circuit for switching the high-speed switching element 101.

[0003] high voltage switch circuit SCa ₁ performs a switching operation of the high-speed switching element 101 in accordance with a switching control signal inputted from outside, in accordance with a switching operation of the high-speed switching element 101 in the high voltage switch circuit SCa _1, high voltage switch perform each high-speed switching element 101 sequentially switching operation in the circuit SCa ₂ ~SCa _n. Incidentally, high-voltage switch circuit SCa ₁ ~SCa _n are each configured by the same circuit.

As described above, the operation of the conventional high-voltage switch is
The high-voltage switch circuit SCa _Two~ SCa_nEach high speed
The switch element 101 includes a high-speed switch circuit SCa₁In
Current due to conduction of the high-speed switch element 101
Or each gate voltage is changed to a gate resistance 1
02 respectively. The gate power at this time
The pressure waveform roughly corresponds to the gate resistor 102 and the corresponding high speed switch.
It becomes an attenuation waveform due to the gate capacitance of the switch element 101.

[0005]

Therefore, if the time constant determined by the gate resistance 102 and the gate capacitance of the corresponding high-speed switch element 101 is increased with respect to the on-time required for the high-voltage switch device 100, the high-speed switch When a main current is flowing through the element 101, a sufficiently high and substantially constant voltage is applied to the gate. However, if the time constant is increased, the period during which the high-speed switch element 101 is conducting becomes longer, and thus there is a problem that the repetition frequency of the switching operation cannot be increased. Further, the high voltage switch circuit SCa ₂ ~SCa _n,
Since the power source or the like for driving is not supplied, it is difficult to provide a circuit for detecting the abnormality of the high voltage switch circuit SCa ₂ ~SCa _n, high voltage switch circuits SCa ₂ ~
There is a problem that can not be detected the destruction of abnormal or element in the SCa _n.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can supply a sufficiently constant gate voltage to a high-speed switch element in each high-voltage switch circuit, and can repeat a switching operation. Obtaining a high-voltage switch device in which a plurality of high-voltage switch circuits can be connected in series and a pulse generator using the high-voltage switch device that can increase the frequency and detect an abnormality of each high-voltage switch circuit With the goal.

[0007]

A high-voltage switch device according to the present invention includes a high-speed switch element formed of a semiconductor that performs high-voltage switching and a plurality of high-voltage switch circuits that perform switching control of the high-speed switch element. The high-speed switch elements of the respective high-voltage switch circuits are connected in series, and when one predetermined high-speed switch element switches in response to an external control signal, the other high-speed switch elements also sequentially switch. In the switch device, each high-voltage switch circuit has a voltage-dividing resistor connected in parallel to the high-speed switching element, and at least one of the high-speed switching elements connected in series is in a conductive state based on a voltage change obtained from the voltage-dividing resistor. And a high-speed switch element by the conduction state detection unit. A switch control unit for applying a voltage to the control signal input terminal of the high-speed switch element to turn on when a conduction state of the high-speed switch element is detected; and a high-speed switch element after a predetermined time from the application of the voltage by the switch control unit. And a shut-off control unit for lowering the control signal input terminal to a predetermined voltage to turn off the high-speed switch element.

In the high-voltage switch device according to the present invention, the switch control section and the cutoff control section operate using a voltage obtained through a parallel circuit of a high-speed switch element and a voltage dividing resistor as a power supply.

Further, in the high-voltage switch device according to the present invention, the cutoff control section includes a connection circuit for connecting a control signal input terminal of the high-speed switch element to a predetermined voltage, and a connection circuit after the switch control section applies the voltage. Depending on the elapsed time,
And a connection control circuit for controlling connection of the connection circuit.

Further, in the high-voltage switch device according to the present invention, the connection control circuit includes a delay circuit.

Further, in the high-voltage switch device according to the present invention, at least one of the switch control units detects a state where the voltage applied to the control signal input terminal of the corresponding high-speed switch element is equal to or lower than a predetermined value, and May be provided.

In the high-voltage switch device according to the present invention, high-speed switch elements formed of a semiconductor that performs high-voltage switching are connected in series, and one predetermined high-speed switch element is switched in response to an external control signal. Then, in each of the other high-speed switch elements, the high-voltage switch device that performs switching sequentially has a high-speed switch element and a voltage-dividing resistor connected in parallel to the high-speed switch element. When detecting that at least one of the connected high-speed switch elements has become conductive, a plurality of high-voltage switch circuits that apply a voltage to a control signal input terminal of the high-speed switch element to make the conductive state, and at least one high-voltage switch circuit A state in which the voltage input to the control signal input terminal of the high-speed switch element in the switch circuit is equal to or lower than a predetermined value Performs detection, in which and a state detection circuit that outputs the detection result.

In the high-voltage switch device according to the present invention, each of the high-voltage switch circuits and the state detection circuit operates using a voltage obtained through a parallel circuit of a high-speed switch element and a voltage dividing resistor as a power supply. .

A pulse generator according to the present invention performs switching control on both ends of a series circuit in which a load is connected in series to a capacitor for charging a voltage from a high-voltage power supply, and generates a predetermined pulse in the load. In the generator, high-speed switching elements formed of semiconductors that perform high-voltage switching are connected in series, and when one predetermined high-speed switching element switches in response to a control signal from the outside, the other high-speed switching elements also Switching at both ends of a series circuit of a capacitor and a load, which sequentially performs switching, detects a state in which a voltage applied to a control signal input terminal of at least one high-speed switching element is equal to or lower than a predetermined value, and outputs the detection result. And a high-voltage switch device for performing the high-voltage switching according to the detection result output from the high-voltage switch device. In which and a power control unit for controlling the output of the high voltage from the power supply.

[0015] Further, the pulse generator according to the present invention comprises:
The high-voltage switch device has a high-speed switching element and a voltage-dividing resistor connected in parallel to the high-speed switching element, and at least one of the high-speed switching elements connected in series is turned on based on a voltage change obtained from the voltage-dividing resistance. A plurality of high-voltage switch circuits that apply a voltage to a control signal input terminal of the high-speed switch element to make a conductive state when the state is detected;
A state detection circuit for detecting a state in which the voltage input to the control signal input terminal of the high-speed switch element in at least one of the high-voltage switch circuits is equal to or lower than a predetermined value, and outputting the detection result.

Further, the pulse generator according to the present invention comprises:
When the power supply control unit detects a state in which the voltage input to the control signal input terminal of the high-speed switch element in at least one high-voltage switch circuit is equal to or less than a predetermined value, the high-voltage power supply from the high-voltage power supply To shut off the output.

Further, a pulse generator according to the present invention comprises:
When the output voltage from the high-voltage power supply is equal to or less than a predetermined value, the power supply controller supplies the high voltage from the high-voltage power supply regardless of the detection result of the state detection circuit.

Further, the pulse generating apparatus according to the present invention comprises:
Each of the high-voltage switch circuits and the state detection circuit operates using a voltage from a high-voltage power supply obtained through a parallel circuit of a high-speed switch element and a resistor as a power supply.

Further, the pulse generator according to the present invention comprises:
Each of the high-voltage switch circuits has a voltage-dividing resistor connected in parallel with the high-speed switching element, and at least one of the high-speed switching elements connected in series becomes conductive from a voltage change obtained from the voltage-dividing resistor. And a switch control unit for applying a voltage to a control signal input terminal of the high-speed switch element to turn on when a conductive state of another high-speed switch element is detected by the conductive state detection unit. And a shutoff control unit that lowers the control signal input terminal of the high-speed switch element to a predetermined voltage and turns off the high-speed switch element after a predetermined time from the application of the voltage by the switch control unit.

Further, the pulse generator according to the present invention comprises:
A connection circuit for connecting the control signal input terminal of the high-speed switch element to a predetermined voltage, and a connection for performing connection control of the connection circuit according to an elapsed time after the voltage is applied by the switch control unit; It comprises a control circuit.

Further, the pulse generating device according to the present invention comprises:
The connection control circuit includes a delay circuit.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on an embodiment shown in the drawings. Embodiment 1 FIG. FIG. 1 is a circuit diagram showing an example of the high-voltage switch device according to Embodiment 1 of the present invention. In FIG. 1, a high-voltage switch device 1 includes a plurality of high-voltage switch circuits SC _{1 to} SC _n having the same circuit configuration (n is a natural number of n> 0).
It is composed of In FIG. 1, since the high-voltage switch circuits SC _{1 to} SC _n have the same circuit configuration, only the internal circuits of the high-voltage switch circuits SC ₁ and SC _n are shown, and other high-voltage switch circuits are omitted.

Each of the high-voltage switch circuits SC _{1 to} SC _n has a corresponding main high-speed switch element IGB using an IGBT for switching a load connected to the high-voltage switch device 1.
A T ₁ ~IGBT _n, respectively, each of said main fast switching device IGBT ₁ ~IGBT _n are connected in series in the forward direction, both ends of the series circuit forms an output terminal of the high voltage switch device 1.

Here, FIG. 2 is a schematic circuit diagram showing an example of a pulse generator using the high-voltage switch device 1 shown in FIG. In the pulse generator 10 shown in FIG.
3. Charge the voltage. When the conduction control signal S is input to the high-voltage switch device 1 from the outside, the output terminals of the high-voltage switch device 1 conduct, and a voltage is applied to the load 14. In such a configuration, the main high-speed switch elements IGBT _{1 to} IGBT _{n of} the high-voltage switch device 1 are both turned on or both are turned on in response to an external control signal S for connection, so that the load 14 is connected between the loads 14. A high voltage pulse is generated.

Returning to FIG. 1, each high-voltage switch circuit SC
Description will be given of a configuration of ₁ to SC _n. Since each of the high-voltage switch circuits SC _{1 to} SC _n has the same configuration, an explanation will be given using an example of an arbitrary high-voltage switch circuit SC _m (m is a natural number of 1 ≦ m ≦ n). High voltage switch circuit SC _m
Are a main high-speed switch element IGBT _m , a first N-channel MOS transistor (hereinafter referred to as an NMOS transistor) QA _m as an auxiliary high-speed switch element, a displacement current detection resistor RA _m , a displacement current detection diode DA _m , a displacement Current detection capacitor CA _m , divided voltage detection resistor R
B _m , a butt diode DB _m , a displacement current detection reactor L _m , and an auxiliary switch gate resistance RC _m .

Further, a high-voltage switch circuit SC_mIs for amplification
Capacitor CB_m, Pulse transformer T _m, Main switch input
Diode DC_m, Feedback diode DD_m, Reflux Daio
De DE_m, Main switch gate resistance RD_m, Voltage dividing resistor RE
_m, And main high-speed switch element IGBT_mGate voltage
Forced discharge circuit G_mIt has.

[0027] and dividing resistors RE _m between the collector and emitter of the main high-speed switching device IGBT _m is connected. The collector of the main high-speed switch element IGBT _m is composed of a displacement current detecting resistor RA _m and a displacement current detecting diode D.
Through a series circuit A _m are connected in series in the forward direction, the displacement current detecting capacitor CA _m and a divided voltage detection resistor RB _m is connected to one end of the parallel circuit connected in parallel. The other end of said parallel circuit, together with the cathode of the freewheeling diode DE _m is connected, the 1NMOS transistor diode DB _m against the displacement current detection reactor L _m via a series circuit connected in series in a forward direction QA
Connected to the gate of _m . The freewheeling diode D
The anode of E _m is connected to the source of the 1NMOS transistor QA _m, between the gate and source of the first 1NMOS transistor QA _m, gate resistor RC _m is connected.

Further, between the drain and the source of the first 1NMOS transistor QA _m, amplifying capacitor CB _m
Series circuit a primary coil connected in series with pulse transformer T _m is connected to. Drain and connection of the amplifying capacitor CB _m of the 1NMOS transistor QA _m is connected to the connection portion between the displacement current detection resistor RA _m and the displacement current detecting diode DA _m. Furthermore, the first N
Source of MOS transistor QA _m and pulse transformer T _m
Is connected to the primary side coil of the pulse transformer _Tm .
Is connected to one end of the next coil is connected to the emitter of the main high-speed switching device IGBT _m.

The pulse transformer T_mSecondary coil
Is the main switch input diode DC_mThrough the lord
High-speed switch element IGBT_mWhen connected to the gate of
And the feedback diode DD_mVia the first NMOS transistor
Qista QA_mConnected to the gate. Furthermore, the main high speed
Switch element IGBT_mBetween the gate and the emitter of
Main switch gate resistance RD_mIs connected. In addition,
Pulse transformer T_mThe other end of the secondary coil of the main switch
Input diode DC_mAnd feedback diode DD_mIs connected
X_mAnd the main high-speed switch element IGBT_mof
Emitter, main switch gate resistance RD_mAnd pulse tiger
Once T_mThe connection part to which the secondary coil of _mToss
You.

On the other hand, the forced discharge circuit G _m is for setting the pulse width W of the gate voltage VG _m applied to the main high-speed switching device IGBT _m, the pulse width setting diode D
F _m , a pulse width setting capacitor CC _m and a pulse width setting resistor RF _m, and a second N which forms a forced discharge switch element.
MOS transistor QB _m and gate resistor R for forced discharge
It is composed of a G _m. Main high-speed switch element IGBT _m
Drain and source of the first 2NMOS transistor QB _m is connected between the gate and emitter of.

A series circuit in which a pulse width setting diode DF _m and a pulse width setting capacitor CC _m are connected in series is connected between the connection portion X _m and the connection portion Y _m, and a pulse width setting capacitor is connected. CC _m pulse width setting resistor RF _m in parallel to is connected. Pulse width setting diode D
Connection J between F _m and pulse width setting capacitor CC _m
m is the second NMOS via the forced discharge gate resistance RG _m
It is connected to the gate of the transistor QB _m.

In such a configuration, the external conduction control signal S is supplied to the first NMO of the high voltage switch circuit SC ₁ .
It is input to the gate of the S transistor QA _1. When the conduction control signal S is not input, the first NMOS
The gate of the transistor QA ₁ are divided voltage determined by dividing resistors RE ₁ is applied. At this time, both ends of the displacement current detection capacitor CA ₁ of the high-voltage switching circuit SC _1, divided voltage is charged. When the conduction control signal S is input, the high-voltage switch circuit SC
The 1NMOS transistor QA ₁ of ₁ begins to conduct, the first
The drain of the NMOS transistor QA ₁ - voltage between the source begins to decrease.

For this reason, the amplifying capacitor CB charged with the divided voltage in the high-voltage switch circuit SC _1
1 out current flows to the 1NMOS transistors QA _1, voltage is generated in the secondary side of the pulse transformer T _1, first the voltage through the feedback diode DD _1, which begins to conduct
It is input to the gate of the NMOS transistor QA _1. From this, the first NMOS transistor QA ₁ accelerates the transition to conduction and eventually becomes completely conductive. For this reason, most of the charge stored in the amplification capacitor CB ₁ is transmitted to the secondary side of the pulse transformer T ₁ , and a sufficiently high voltage is applied to the gate of the main high-speed switching device IGBT ₁ , and IGBT ₁ is fully conducting.

[0034] When the main high-speed switching device IGBT ₁ becomes conductive, the voltage drop due to dividing resistors RE ₁ is applied to each of the other high-voltage switching circuit SC ₂ to SC _n. Hereinafter, since the operations of the high-voltage switch circuits SC _{2 to} SC _n are the same, an explanation will be given using an example of an arbitrary high-voltage switch circuit SC _p (p is a natural number of 2 ≦ p ≦ n). When the voltage drop by the voltage dividing resistor RE ₁ is applied, the displacement current detecting resistor RA _p , the displacement current detecting diode DA _p , the displacement current detecting capacitor CA _p , and the displacement current detecting device in the high voltage switch circuit SC _p . Reactor L _p , butting diode DB _p ,
Displacement current flows from the gate of the first 1NMOS transistor QA _p to the source. The displacement current reaches the gate threshold of the first 1NMOS transistor QA _p drain - source voltage of drops slightly.

Eventually, the displacement current detecting diode DA _p
Becomes reverse bias, and no displacement current is supplied. However, the electromagnetic energy stored in the displacement current detection reactor L _p is, for circulating through the circulating diode DE _p, subsequently gate voltage of the 1NMOS transistor QA _p increases, the 1NMOS transistor QA _p continued , The voltage between the drain and the source decreases.

When the drain voltage of the first NMOS transistor QA _p becomes lower than the voltage of the amplification capacitor CB _p which has been charged in advance with the divided voltage, a current starts flowing from the amplification capacitor CB _p to the first NMOS transistor QA _p. a voltage is generated on the secondary side of the pulse transformer T _p. Thereafter, similarly to the operation of the high voltage switch circuit SC _1,
Voltage is supplied to the gate of the main high-speed switching device IGBT _p. Thus, each of the high-voltage switch circuits SC _{2 to} S
Main high-speed switching elements IGBT _{2 to} IGBT _n in C _n
Respectively become fully conductive. By such an operation,
Each primary high-speed switch element of the high-voltage switching circuit SC ₁ to SC _n are fully conductive, respectively.

Each of the main high-speed switching elements IGBT _{1 to} IGB
After the T _n has been conducting all, the main high-speed switch element IGBT ₁
Gate voltages of ～IGBT _n is discharged by a corresponding main switch gate resistance and forced discharge circuit. Also,
Each gate voltage of the first NMOS transistor is discharged by the auxiliary switch gate resistance, and all the main high-speed switching elements IGBT _{1 to} IGBT _n are turned off, cut off, and return to the original state.

[0038] Thus, only the input of the conduction control signal S to the high voltage switch circuit SC ₁ which forms a high-speed switch master stage, the main high-speed switching element of the high-voltage switching circuit SC ₂ to SC _n constituting the high-speed switch dependent stage IGBT
_{2 ~IGBT n} are all conductive. The displacement currents flowing through the respective high-voltage switch circuits SC ₂ to SC _n by the main high-speed switching device IGBT ₁ is turned on, since the flow in common to all the high-voltage switching circuit SC ₂ to SC _n, the main high-speed switch element IGBT ₂ ~IGBT _n is conductive simultaneously. As a result, a high conduction speed can be maintained even when the number of main high-speed switching elements connected in series is increased.

Next, FIG. 3 is a diagram showing the waveform of each part in the forced discharge circuit G _m as shown in FIG. 1, in FIG. 3, (a) the gate voltage VG _m of the main high-speed switching device IGBT _m shows a waveform, (b) is a waveform of the voltage VJ _m of the connecting portion J _m, (c) the first 2NMOS transistor Q
shows the waveform of the gate voltage VK _m of b _m. With reference to FIG. 3, the operation of the forced discharge circuit G _m.

[0040] Each main high speed switching device IGBT ₁ ~IGBT _n of the high-pressure switching device 1 at time t0 is conductive, the gate of the main high-speed switching device IGBT _m already by the pulse transformer the T _m can retain a sufficient value. At the same time, the pulse width setting capacitor C is passed through the pulse width setting diode DF _m connected to the secondary coil of the pulse transformer T _m.
The voltage VJ _m is charged in the C _m. The charged voltage VJ _m
Is the 2NMOS through the forced discharge gate resistor RG _m
It is applied to the gate of the transistor QB _m. 2nd NMO
Gate voltage VK _m of S transistor QB _m gradually increases to reach the threshold of the 2NMOS transistor QB _m at time t1.

From this, the second NMOS transistor
QB_mTurns on and conducts, and the main high-speed switching element IGBT_m
To discharge the gate charge. Second NMOS transistor
QB_mGate voltage VK_mIncreases further after time t1,
High-speed switch element IGBT _mDischarges the gate charge of
Can be done. Eventually, the voltage VJ_mAnd gate power
Pressure VK_mIs the pulse width setting resistor RF_mDischarged by
And return to the original state. That is, the voltage VJ_mAnd games
Voltage VK_mDischarge speed of the main high-speed switching device IGB
T_mTime to switch off
You. Therefore, the pulse width setting diode D
F_m, Pulse width setting capacitor CC_mAnd pulse width setting
Resistance RF_mForm a delay circuit.

[0042] Thus, the high voltage switch device in the first embodiment, the forced discharge circuit G ₁ ~G _n, discharging forcibly charge the main high-speed switching device IGBT ₁ ~IGBT _n, the voltage VJ _m and also in the gate voltage VK _m, and adapted to discharge the time determined by the pulse width setting resistor RF ₁ ~RF _n. Therefore, the main switch gate resistor RD ₁ ~ Rd _n of the main high-speed switching device IGBT ₁ ~IGBT _n is sufficiently large gate voltage VG ₁
Also by increasing the flatness of ~VG _n, each of the main high-speed switch element I
Since a high repetition frequency of the switching operation of the GBT _{1 to} IGBT _n can be achieved, a sufficiently constant gate voltage can be supplied to the high-speed switching element in each high-voltage switch circuit, and the switching operation of the high repetition frequency can be performed. Can be realized.

Embodiment 2 In the high-voltage switch device 1 according to the first embodiment, each of the high-voltage switch circuits SC _{1 to} SC
Abnormality in C _n and main high-speed switching elements IGBT _{1 to} IG
BT _n destruction may be detected, and such a configuration is referred to as a second embodiment of the present invention. FIG. 4 is a circuit diagram showing an example of a high-voltage switch device according to Embodiment 2 of the present invention. In FIG. 4, the high-voltage switch circuit S
The internal circuits of C _{1 to} SC _n are omitted because they are the same as those in FIG.

In FIG. 4, the high-voltage switch device 20 is
A plurality of high-voltage switch circuits SC having the same circuit configuration₁~ SC
_nAnd each high-voltage switch circuit SC₁~ SC_nProvided corresponding to
Abnormality detection circuit UD₁~ UD_nIt is composed of
In FIG. 4, the abnormality detection circuit UD₁~ UD_nAre the same circuit
Abnormality detection circuit UD₁, UD_n-1And U
D _nThe internal circuit of
Omitted.

Each abnormality detection circuit UD _m (1 ≦ m ≦ n)
Abnormality detection diode DG _m, abnormality detection capacitor C
D _m , discharge resistance RH _m , threshold setting zener diode ZD _m , abnormality detection pulse transformer TA _m and NMO
It is composed of S transistor QC _m.

Abnormality detection circuit UD₁In the high pressure switch
Switch SC₁Connection part X₁Abnormality detection diode DG₁
Is connected to the diode DG for abnormality detection.₁of
Cathode and high voltage switch circuit SC₁Connection part Y₁Between
Is the abnormality detection capacitor CD ₁And discharge resistor RH₁Average
Connected to a column. Further, a diode DG for abnormality detection
₁Has a threshold setting Zener diode Z
D₁Is connected to a Zener for threshold setting.
Iod ZD₁Is the abnormality detection circuit UD_Two(Shown
NMOS transistor QC_Two(Not shown)
Connected to the drain of

Further, one end of the primary side coil of the abnormality detection pulse transformer TA ₁ is the abnormality detection circuit UD ₂ NMOS
The source of the transistor QC ₂ is connected, the other end of the primary coil is connected to the connecting portion Y ₁ of the high-voltage switching circuit SC _1. On the other hand, the abnormality detection pulse transformer TA ₁
The following side coil is connected between the gate and source of the NMOS transistor QC _1. The drain of the NMOS transistor QC ₁ forms the abnormality detection terminal a of the high-voltage switch device 20, and the source of the NMOS transistor QC ₁ forms the abnormality detection terminal b of the high-voltage switch device 20.

Next, the abnormality detection circuit UD_Two~ UD_n-1Is the same
Abnormality detection circuit UD_i(I is 2 ≦ i
≤n-1). Abnormality detection circuit U
D_iIn the high-voltage switch circuit SC_iConnection part X_iDifferent
Normal detection diode DG_iAnode connected, abnormal
Detection diode DG_iCathode and high voltage switch circuit
SC_iConnection part Y_iBetween the capacitor C for abnormality detection
D _iAnd discharge resistor RH_iAre connected in parallel. Furthermore,
Abnormality detection diode DG _iThreshold value
Constant Zener Diode ZD_iIs connected,
Zener diode ZD for threshold setting_iThe anode of
Abnormality detection circuit UD_{i + 1}NMOS transistor Q at
C_{i + 1}Connected to the drain of

One end of the primary coil of the pulse transformer TA _i for abnormality detection is connected to the NMO of the abnormality detection circuit UD _{i + 1} .
The source of the S transistor QC _{i + 1} is connected, and the other end of the primary coil is connected to a connection Y _i of the high-voltage switch circuit SC _i . On the other hand, the abnormality detection pulse transformer TA _i
The secondary coil is connected between the gate and source of the NMOS transistor QC _i. Thus, between one end of the primary coil of the abnormality detecting circuit Zener threshold value setting diodes in UD _i ZD _i and abnormality detection pulse transformer TA _i, NMOS transistor in the abnormality detecting circuit UD i _{+ 1} The drain and source of QC _{i + 1} are connected.

Next, the abnormality detection circuit UD_nAt high pressure
Switch circuit SC_nConnection part X_nAbnormality detection diode
DG_nIs connected to the diode D for abnormality detection.
G_nCathode and high-voltage switch circuit SC_nConnection part Y_nWhen
Between, the abnormality detection capacitor CD_nAnd discharge resistor R
H_nAre connected in parallel. In addition, an abnormality detection diode
DG_nZener die for threshold setting
Aether ZD_nIs connected to the threshold setting tool.
Ener diode ZD_nIs the pulse for abnormality detection
Trans TA_nConnected to one end of the primary coil
You. In addition, abnormality detection pulse transformer TA_nPrimary side
The other end of the il is a high voltage switch circuit SC_nConnection part Y _nContact
Connected, pulse transformer TA for abnormality detection_nSecondary carp
Is the NMOS transistor QC_nWith gate and source
Connected between

In such a configuration, the abnormality detection circuit U
In D _n, when the output voltage on the secondary coil of the pulse transformer T _n is generated in the high voltage switch circuit SC _n, through the abnormality detection diode DG _n, the voltage stored in the abnormality detecting capacitor CD _n. For example, when the main high-speed switching device IGBT _n becomes a short-circuit state to break is not charged charge for the amplification capacitor CB _n of the high-voltage switching circuit SC _n, in the secondary coil of the pulse transformer T _n since the voltage is not generated, a voltage is not generated in the abnormality detecting capacitor CD _n.

[0052] In a normal state, the voltage charged to the abnormality detecting capacitor CD _n is abnormality detection pulse transformer TA _n via a Zener diode ZD _n threshold value setting
, And from the secondary coil of the pulse transformer TA _n for abnormality detection to the gate of the NMOS transistor QC _n . Along with this, NMOS transistor QC _n conducts ON.

Next, also in the abnormality detection circuit UD _n-1 ,
Although the detection circuit has substantially the same configuration, the only difference is that the output of the abnormality detection capacitor CD _n-1 passes through the NMOS transistor QC _n of the abnormality detection circuit UD _{n and} the pulse transformer TA _n for abnormality detection. _- a point which is input to the _1.
From this, each output signal of the abnormality detection circuits UD _n-1 and UD _n is consequently ANDed with AND.
If a short circuit either one of the main high-speed switching device IGBT _n and IGBT _n-1 is destroyed, NMOS transistor QC _n-1 of the abnormality detection circuit UD _n-1 becomes nonconductive off.

Further, the abnormality detection circuit UD₁~ UD_n-2smell
Even the abnormality detection circuit UD_n-1Has the same configuration as
You. FIG. 5 is a circuit diagram of each abnormality detection circuit UD shown in FIG.₁~ UD_n
FIG. 5 is a diagram showing an example of waveforms of the respective units in a normal state. What
In FIG. 5, the abnormality detection circuit UD ₁And UD_nThe waves of each part
Indicates the shape of each part in the abnormality detection circuit.
Are omitted because they are the same. You can see from Figure 5
As described above, the abnormality detection circuit UD₁NMOS transistor in
Jista QC₁Means each abnormality detection circuit UD₁~ UD_nIn
All abnormality detection capacitors CD₁~ CD_nAt the same time
When pressure is generated, that is, each high-voltage switch circuit SC
₁~ SC_nOnly when all are operating normally
Becomes

Therefore, each main high-speed switching element I
If any one of GBT _{1 to} IGBT _n is broken and short-circuited, an abnormality detection circuit connected to the high-voltage switch circuit having the main high-speed switch element in the short-circuit state
The voltage on both ends of the abnormality detection capacitor does not occur, NMOS transistor QC ₁ abnormality detection circuit UD ₁ is turned off to cut off. Therefore, by detecting the state of the NMOS transistor QC ₁ by the abnormality detection circuit UD _1, it is possible to detect the abnormality of the high voltage switch device 20. The threshold value setting zener diodes ZD _{1 to} ZD _n are provided for distinguishing noise and the like.

Next, FIG. 6 shows the high-voltage switch device 2 shown in FIG.
FIG. 2 is a schematic circuit diagram showing an example of a pulse generator using 0. In FIG. 6, the same components as those in FIG. 2 are denoted by the same reference numerals. 6, a pulse generator 30 includes a high-voltage power supply 11, a charging resistor 12, a main capacitor 13, and a load 1.
4. It is composed of a high-voltage switch device 20, a high-voltage power supply control circuit 31, and a cutoff switch SW.

The main capacitor 13 is charged with a voltage from the high voltage power supply 11 through the cutoff switch SW and the charging resistor 12. When the conduction control signal S from the outside is input to the high-voltage switch device 20, the high-voltage switch device 20
Are conducted, and a voltage is applied to the load 14. In such a configuration, the main high-speed switching element I of the high-voltage switch device 20 is controlled in response to an external conduction control signal S.
A high voltage pulse is generated between the loads 14 when the GBT _{1 to} IGBT _n are both in a conducting state or in a blocking state.

On the other hand, the high-voltage power supply control circuit 31 controls the interruption of the interruption switch SW in accordance with the abnormality detection results indicated by the abnormality detection terminals a and b of the high-voltage switch device 20.
Specifically, the high-voltage power supply control circuit 31 has an abnormality detection terminal a
And when the detection of abnormality from b shown, so that the voltage from the high voltage power supply 11 is not applied to the main high-speed switching device IGBT ₁ ~IGBT _n of the main capacitor 13 and the high voltage switch device 20 opens the shut-off switch SW . When the high voltage power supply control circuit 31 indicates that no abnormality is detected from the abnormality detection terminals a and b, the high voltage power supply 11 closes the cutoff switch SW and the voltage from the high voltage power supply 11 Main high-speed switch element I
The voltage is applied to GBT _{1 to} IGBT _n .

The high-voltage power supply control circuit 31 includes a pull-up resistor 41, an inverter 42, a diode 43, and a capacitor 4.
4, a discharge resistor 45, an OR circuit 46, and a comparator 47. The high-voltage power supply control circuit 31 pulls up the abnormality detection terminal a of the high-voltage switch device 20 with the pull-up resistor 41 and grounds the abnormality detection terminal b. Further, the abnormality detection terminal a is connected to one input terminal of the OR circuit 46 via the inverter 42 and the diode 43, and a capacitor 4 is connected between the one input terminal of the OR circuit 46 and the ground.
4 and the discharge resistor 45 are connected in parallel.

On the other hand, a predetermined voltage Vref is externally applied to the non-inverting input terminal of the comparator 47, and the inverting input terminal is connected to the connection between the charging resistor 12 and the cutoff switch SW. The output terminal of the comparator 47 is an OR circuit 4
The output terminal of the OR circuit 46 is connected to the control signal input terminal of the cutoff switch SW to which the open / close control signal is input.

Here, the connection portion between the pull-up resistor 41 and the abnormality detection terminal a is N1, one input terminal of the OR circuit 46 is N2, the other input terminal of the OR circuit 46 is N3, and the OR circuit 4
The output terminal of No. 6 is N4. The binary signal at the connection N1 is inverted by the inverter 42 and input to the capacitor 44 via the diode 43. Since the time constants of the capacitor 44 and the discharge resistor 45 are set to be sufficiently larger than the cycle of the switching operation performed repeatedly in the high-voltage switch device 20, the connection portion N1 is at a low level, indicating that the connection is normal. , The input terminal N2 is always at the high level.

On the other hand, each main high-speed switch of the high-voltage switch device 20
Switch element IGBT₁~ IGBT_nAre all normal
Also, when the output voltage of the high-voltage power supply 11 is low, the connection portion N1 is Lo.
There is a state where it does not become w level. Output power of high voltage power supply 11
If the pressure is low, the amplification capacitor CB₁~ CB_nHigh enough
Since no voltage is accumulated, the abnormality detection capacitor CD ₁
~ CD_nDoes not generate enough voltage. Abnormality detection circuit U
D₁~ UD_nMay determine that such a condition is abnormal.
is there.

Therefore, the charging resistor 12 and the cutoff switch SW
Assuming that the voltage at the connection portion with VH is VH, when the voltage VH becomes lower than the predetermined voltage Vref, the cutoff switch SW is forcibly closed and brought into a conductive state. That is, as shown in FIG. 7, when the output voltage of the high-voltage power supply 11 decreases and the voltage VH becomes lower than the predetermined voltage Vref, the output terminal of the comparator 47, that is, the input terminal N3 of the OR circuit 46 becomes High level, The output terminal N4 of the OR circuit 46 is connected to the input terminal N2.
High level irrespective of the voltage level of. Therefore, the abnormality detection circuit UD ₁ in the high-voltage switch device 20
Regardless abnormality detection result of ~UD _n, cutoff switches SW
Closes and becomes conductive.

When the voltage VH becomes higher than the predetermined voltage Vref, the input terminal N3 of the OR circuit 46 goes low, so that the output terminal N4 of the OR circuit 46 goes to the voltage level input to the input terminal N2. Depending on
Abnormality detection circuits UD _{1 to} U in high-voltage switch device 20
The voltage level varies depending on the abnormality detection result of D _n. Thus, the voltage level of the output terminal N4 of the OR circuit 46, to become as determined only by the input voltage level at the input terminal N2, the high voltage switch device 20 abnormality detection circuit UD ₁ ~
UD _n detects the abnormality, the connection portion N1 is a cut-off switch SW is High level is forcibly cut off.

[0065] Thus, high voltage switch device of the second embodiment, the abnormality detection circuit UD ₁ ~UD _n for detecting the high voltage switch device, the destruction of the main high-speed switching device IGBT ₁ ~IGBT _n in the first embodiment Was provided. From this, the same effect as in the first embodiment can be obtained, and the main high-speed switching elements IGBT _{1 to} IGBT _n can be obtained.
When any one of the main high-speed switching elements is detected to be in a short-circuit state, the supply of high-voltage power to the high-voltage switch circuits SC ₁ to SC _n is stopped to prevent further main high-speed switching elements from being destroyed. Can be.

[0066]

According to the first aspect of the present invention, the high-voltage switch device applies a voltage to the control signal input terminal of the high-speed switch element by the switch control unit to make the high-speed switch element conductive, and after a predetermined time,
A shutoff control unit for forcibly turning off the high-speed switch element is provided. For this reason, the resistance connected to the control signal input terminal of each high-speed switching element, for example, the gate resistance in the case of IGBT or FET, and the base resistance in the case of a bipolar transistor, are made sufficiently large to be applied to the control signal input terminal. Even if the flatness of the voltage is increased, the switching speed of the high-speed switching element can be increased, so that a sufficiently constant voltage can be supplied to the control signal input terminal of each high-speed switching element, and A high frequency switching operation can be realized.

According to a second aspect of the present invention, in the high voltage switch device according to the first aspect, the switch control section and the cutoff control section are operated using a voltage obtained through a parallel circuit of a high-speed switch element and a voltage dividing resistor as a power supply. did. From this,
The present invention can be applied to a high-voltage switch device having no driving power supply.

According to a third aspect of the present invention, in the high voltage switch device according to any one of the first and second aspects, specifically, the cut-off control section is connected to a control signal input terminal of the high-speed switch element to a predetermined voltage. And a connection control circuit that controls the connection of the connection circuit according to the elapsed time after the voltage is applied by the switch control unit. From this, it is possible to realize a switching operation of the high-speed switching element with a high repetition frequency.

According to a fourth aspect of the present invention, in the high voltage switch device according to the third aspect, since the connection control circuit is constituted by a delay circuit, the high-speed switching operation of the high-speed switching element can be performed with a simple circuit configuration. Can be realized.

According to a fifth aspect of the present invention, in the high voltage switch device according to any one of the first to fourth aspects, the state where the voltage applied to the control signal input terminal of the high speed switch element is equal to or lower than a predetermined value is detected. The result of the detection is output. This makes it possible to detect short-circuit breakdown of the high-speed switch element.

The high-voltage switch device according to claim 6 detects a state where the voltage input to the control signal input terminal of the high-speed switch element in at least one high-voltage switch circuit is equal to or lower than a predetermined value, and performs the detection. Output result. From this, it is possible to detect that one of the high-speed switch elements is broken and short-circuited.

According to a seventh aspect of the present invention, in the high voltage switch device according to the sixth aspect, each of the high voltage switch circuits and the state detection circuit are operated using a voltage obtained through a parallel circuit of a high speed switch element and a voltage dividing resistor as a power supply. I made it. Therefore, the present invention can be applied to a high-voltage switch device having no driving power supply.

The pulse generator according to claim 8 detects a state in which the voltage applied to the control signal input terminal of at least one high-speed switch element is equal to or less than a predetermined value in the high-voltage switch device, and outputs the voltage from the high-voltage switch device. A power control unit for controlling the output of the high voltage from the high voltage power supply according to the detected result. From this, when it is detected that one of the high-speed switch elements has been broken and short-circuited,
By stopping the supply of the high-voltage power to the high-voltage switch device, the destruction of other high-speed switch elements can be prevented, and the reliability can be improved.

In a ninth aspect of the present invention, in the pulse generation device according to the ninth aspect, the voltage input to the control signal input terminal of the high-speed switch element in at least one high-voltage switch circuit is equal to or less than a predetermined value. And a result of the detection is output. From this, it is possible to detect that one of the high-speed switch elements is broken and short-circuited.

The pulse generator according to claim 10 is the pulse generator according to claim 8, wherein the voltage input to the control signal input terminal of the high-speed switch element in at least one high-voltage switch circuit is equal to or less than a predetermined value. Is detected by the state detection circuit, the high voltage output from the high voltage power supply is cut off and stopped. Therefore, when one of the high-speed switching elements is broken and short-circuited, the other high-speed switching elements can be prevented from being broken, and the reliability can be improved.

According to a twelfth aspect of the present invention, in the pulse generator according to the ninth or tenth aspect, when the output voltage from the high-voltage power supply is equal to or lower than a predetermined value, regardless of the detection result of the state detection circuit. A high voltage was supplied from a high voltage power supply. From this, when the output voltage of the high-voltage power supply is low enough to prevent the sequential destruction of each high-speed switching element, it is possible to unnecessarily shut off the high-voltage output from the high-voltage power supply so as not to stop it. Thus, stable pulse generation can be performed.

According to a twelfth aspect of the present invention, in the pulse generator according to any one of the ninth to eleventh aspects, specifically,
Each of the high-voltage switch circuits and the state detection circuit are operated using a voltage from a high-voltage power supply obtained through a parallel circuit of a high-speed switch element and a voltage dividing resistor as a power supply. For this reason, it is possible to use a high-voltage switch device having no driving power supply.

According to a thirteenth aspect of the present invention, in the pulse generator according to any one of the ninth to twelfth aspects, a voltage is applied to the control signal input terminal of the high-speed switch element by the switch control unit to make the switch conductive for a predetermined time. Later, a shutoff control unit for forcibly turning off the high-speed switch element was provided.
For this reason, the resistance connected to the control signal input terminal of each high-speed switching element, for example, the gate resistance in the case of IGBT or FET, and the base resistance in the case of a bipolar transistor, are made sufficiently large to be applied to the control signal input terminal. The switching speed of the high-speed switching element can be increased even if the flatness of the voltage is increased, so that a sufficiently constant voltage can be supplied to the control signal input terminal of each high-speed switching element, and Switching operation can be realized, and a high-frequency pulse signal can be generated.

According to a fourteenth aspect of the present invention, in the pulse generating device according to the thirteenth aspect, the disconnection control unit includes a connection circuit for connecting a control signal input terminal of the high-speed switch element to a predetermined voltage, and a switch control circuit. And a connection control circuit that controls connection of the connection circuit in accordance with the elapsed time after the voltage is applied by the unit. Thus, a high-speed switching operation of the high-speed switching element can be realized.

According to a fifteenth aspect of the present invention, in the pulse generating device according to the fourteenth aspect, since the connection control circuit is constituted by a delay circuit, the high-speed switching operation of the high-speed switching element can be performed with a simple circuit configuration. Can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an example of a high-voltage switch device according to Embodiment 1 of the present invention.

FIG. 2 is a schematic circuit diagram showing an example of a pulse generator using the high-voltage switch device 1 of FIG.

3 is a diagram showing a waveform example of each section in the forced discharge circuit G _m as shown in FIG.

FIG. 4 is a circuit diagram showing an example of a high-voltage switch device according to Embodiment 2 of the present invention.

5 is a diagram showing a waveform example of each section in the normal of each abnormality detection circuit UD ₁ ~UD _n shown in FIG.

6 is a schematic circuit diagram illustrating an example of a pulse generator using the high-voltage switch device 20 of FIG.

FIG. 7 is a diagram showing a logical state of each unit shown in FIG. 6;

FIG. 8 is a circuit diagram showing an example of a conventional high-voltage switch device.

[Explanation of symbols]

1,20 high-voltage switch device, 10,30 pulse generator, 11 high-voltage power supply, 12 charging resistor, 13
Main capacitor, 14 load, SC ₁ to SC _n high voltage switch circuit, IGBT ₁ ~IGBT _n main high-speed switch element, G ₁ ~G _n forced discharge circuit, UD ₁ ~UD _n anomaly detection circuit, 31 high-voltage power supply control circuit, SW Shut off switch.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Masaki Yamada 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Mitsubishi Electric Corporation (reference) 5J055 AX02 AX36 BX10 CX07 DX09 DX44 DX88 EX06 EY05 EY07 EY10 EY12 EY17 EZ10 EZ66 EZ67 FX05 FX10 FX12 FX20 FX28 FX32 GX01 GX02

Claims (15)

[Claims] 1. A high-speed switch device comprising a plurality of high-voltage switch circuits each having a high-speed switch element formed of a semiconductor that performs high-voltage switching and performing switching control of the high-speed switch device. Are connected in series, and when one predetermined high-speed switch element switches in response to an external control signal, the other high-speed switch elements also sequentially switch. A conduction state detection unit having a voltage dividing resistor connected in parallel to the switching element, and detecting that at least one of the high-speed switching elements connected in series is in a conducting state from a voltage change obtained from the voltage dividing resistance When the conduction state detection unit detects the conduction state of another high-speed switch element, the high-speed switch A switch control unit for applying a voltage to the control signal input terminal of the element to make the state conductive, and a predetermined time after the voltage is applied by the switch control unit, the control signal input terminal of the high-speed switch element is reduced to a predetermined voltage A high-voltage switch device comprising: a cut-off control unit for setting the high-speed switch element to a cut-off state. 2. The switch control unit and the cutoff control unit,
The high-voltage switch device according to claim 1, wherein the high-voltage switch device operates using a voltage obtained through a parallel circuit of a high-speed switch element and a voltage dividing resistor as a power supply. 3. The disconnection control unit includes: a connection circuit that connects a control signal input terminal of the high-speed switch element to a predetermined voltage; and The high-voltage switch device according to claim 1, further comprising: a connection control circuit that controls connection of the connection circuit. 4. The high-voltage switch device according to claim 3, wherein the connection control circuit includes a delay circuit. 5. A state in which at least one of the switch control units detects a state in which a voltage applied to a control signal input terminal of a corresponding high-speed switch element is equal to or lower than a predetermined value, and outputs a result of the detection. The high-voltage switch device according to any one of claims 1 to 4, further comprising a detection unit. 6. A high-speed switching element formed of a semiconductor that performs high-voltage switching is connected in series,
When a predetermined one high-speed switch element is switched in response to an external control signal, the other high-speed switch elements are also sequentially switched. In the high-voltage switch device, the high-speed switch element and a component connected in parallel to the high-speed switch element are provided. When detecting that at least one of the high-speed switching elements connected in series has become conductive from a voltage change obtained from the voltage-dividing resistance, a voltage is applied to the control signal input terminal of the high-speed switching element. A plurality of high-voltage switch circuits to be brought into conduction by detecting a state in which a voltage input to a control signal input terminal of a high-speed switch element in at least one of the high-voltage switch circuits is equal to or less than a predetermined value; A high-voltage switch device comprising: a state detection circuit that outputs a signal. 7. The high-voltage switch according to claim 6, wherein each of the high-voltage switch circuits and the state detection circuit operates using a voltage obtained through a parallel circuit of a high-speed switch element and a voltage-dividing resistor as a power supply. Switch device. 8. A pulse generator for performing switching control on both ends of a series circuit in which a load is connected in series to a capacitor for charging a voltage from a high-voltage power supply to generate a predetermined pulse in the load. The high-speed switching elements formed of switching semiconductors are connected in series, and when one predetermined high-speed switching element switches in response to an external control signal, the other high-speed switching elements also sequentially switch, and at least A high-voltage switch device that detects a state where a voltage applied to a control signal input terminal of one high-speed switch element is equal to or lower than a predetermined value and outputs the detection result, and that performs switching at both ends of the series circuit of the capacitor and the load; Output of a high voltage from a high voltage power supply according to the detection result output from the high voltage switch device. Pulse generator, characterized in that it comprises a power control unit for controlling, the. 9. The high-voltage switch device, comprising: the high-speed switch element; and a voltage-dividing resistor connected in parallel to the high-speed switch element, and a high-speed switch connected in series based on a voltage change obtained from the voltage-dividing resistor. A plurality of high-voltage switch circuits for applying a voltage to a control signal input terminal of the high-speed switch element to turn on when detecting that at least one of the elements has become conductive; and a high-speed switch in at least one of the high-voltage switch circuits. 9. The pulse generator according to claim 8, further comprising: a state detection circuit that detects a state where a voltage input to a control signal input terminal of the element is equal to or less than a predetermined value and outputs a result of the detection. . 10. The power supply control unit, when a state in which a voltage input to a control signal input terminal of a high-speed switch element in at least one high-voltage switch circuit is equal to or less than a predetermined value is detected by the state detection circuit, The pulse generator according to claim 9, wherein the output of the high voltage from the power supply is cut off and stopped. 11. The power supply control section supplies a high voltage from a high voltage power supply regardless of a detection result of the state detection circuit when an output voltage from the high voltage power supply is equal to or lower than a predetermined value. A pulse generator according to claim 9 or claim 10. 12. The apparatus according to claim 9, wherein each of the high-voltage switch circuits and the state detection circuit operates using a voltage from a high-voltage power supply obtained through a parallel circuit of a high-speed switch element and a resistor as a power supply. Item 12. The pulse generator according to any one of Items 11. 13. Each of the high-voltage switch circuits has a voltage-dividing resistor connected in parallel to the high-speed switching device, and at least one of the high-speed switching devices connected in series based on a voltage change obtained from the voltage-dividing resistor. A conduction state detecting unit for detecting that one of the high-speed switching elements has become conductive, and applying a voltage to a control signal input terminal of the high-speed switching element when the conduction state of the other high-speed switching element is detected by the conduction state detecting unit. A switch control unit for turning on the high-speed switch element, and a cut-off control for setting the control signal input terminal of the high-speed switch element to a predetermined voltage to shut off the high-speed switch element after a predetermined time from the application of the voltage by the switch control unit And a unit.
The pulse generator according to any one of claims 1 to 12. 14. The disconnection control unit includes: a connection circuit that connects a control signal input terminal of the high-speed switch element to a predetermined voltage; and a connection circuit that connects the control signal input terminal of the high-speed switch element to a predetermined voltage. 14. The pulse generator according to claim 13, comprising: a connection control circuit that controls connection of the connection circuit. 15. The pulse generator according to claim 14, wherein said connection control circuit is constituted by a delay circuit.