JP3005367B2 - Drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive circuit for switching an MOS-bipolar composite device such as an IGBT or a MOS thyristor, and more particularly to a drive circuit for a main switching device of a pulse power supply such as an excimer laser or a copper vapor laser. It is suitable for application.

[0002]

2. Description of the Related Art FIG. 5 shows, for example, Electronic Technology, August 1991, Vol. 33No. 10 (Nikkan Kogyo Shimbun Co., Ltd.,
P. FIG. 33 is a circuit configuration diagram showing a conventional drive circuit of the IGBT shown in 33). In the figure, 1 is an IGBT having an anti-parallel connected diode in its package,
1a is a capacitance between the gate G and the emitter E of the IGBT 1, 2 is an NPN-junction bipolar transistor as a first switching element, 3 is a PNP-junction bipolar transistor as a second switching element, 4 is a gate resistance, Reference numeral 5 denotes a DC power supply for applying a reverse bias voltage, for example, -5 V, between the gate G and the emitter E of the IGBT 1.

[0003] 6 receives driving a bipolar transistor 3 of the PNP junction is a first bipolar transistor 2 and the second switching elements of the NPN junction as a switching element to input drive signal V _a from the outside Circuit, 7 and 8 are resistors, 9 is light emitting diode 9a, light receiving element 9b, and light emitting diode 9a and light receiving element 9b
Comprising a shield 9c for electromagnetic shielding between a IGBT drive signal V _a and the drive circuit electrically photocoupler for insulating from the outside.

[0004] Furthermore, although 10 is in the original drawing of the document are omitted, the DC power supply output voltage postscript for explaining the operation, for example, 20V, 11 and 12 resistors, 13 a IGBT drive signal V _a from the outside I for inverted output
Although C and 14 are omitted in the original drawing of the literature, they are DC power supplies whose output voltage is, for example, 20 V added for explanation of the operation.

Next, an operation of the IGBT drive circuit when the IGBT 1 is changed from an off state to an on state (turned on) will be described with reference to FIG. 6 showing operation waveforms of various parts. First, in a state that does not enter the IGBT drive signal V _a from the outside, the inverted output of IC13 is a DC power source 14
(20V) supplied from the DC power supply 14
To the light emitting diode 9a in the photocoupler 9 from the current I _S
Is not supplied. Accordingly, the light from the light emitting diode 9a is not output, the output voltage V _c of the photocoupler 9 is zero.

[0006] Since the output voltage V _c of the photocoupler 9 is zero, between the base B- emitter E of the bipolar transistor 2 of the NPN junction is not forward biased, the base current does not flow during this time. Therefore, bipolar transistor 2 is off. On the other hand, a forward bias is applied between the base B and the emitter E of the PNP junction bipolar transistor 3, and a base current flows during this time. Therefore, bipolar transistor 3 is on.

When the bipolar transistor 2 is off,
Since the bipolar transistor 3 is on, the IGBT
1, a reverse bias voltage (−5 V) of the DC power supply 5 is applied via the bipolar transistor 3 and the gate resistor 4 to the IGBT 1, so that the IGBT 1 is off and the IGBT 1 has the current I. _c does not flow.

[0008] Then, at time t _a of FIG. 6, when the IGBT drive signal V _a from the outside is input to IC13, the inverted output V _b the time t _a from the IC13 inherent delay time d _a delayed in time It becomes the ground potential at t _b . The inverted output V _b is ground potential, a current I _S is supplied to the light emitting diodes 9a in the photocoupler 9 through the resistor 11 from the DC power source 14, the light emitting diodes 9a outputs the light.

When the output light is input to the light receiving element 9b through the shield 9c, the output voltage V
_c, the photo coupler 8-specific DC time than time t _b d _b
The voltage (20 V) supplied from DC power supply 9 at time t _c with a delay only. When the output voltage V _c becomes 20 V, N
Since the base B and the emitter E of the PN junction bipolar transistor 2 are forward-biased, a base current flows during this time, and the bipolar transistor 2 is turned on.
On the other hand, since no forward bias is applied between the base B and the emitter E of the bipolar transistor 3 having the PNP junction, no base current flows during this time, and the bipolar transistor 3 is turned off.

When the bipolar transistor 2 is turned on and the bipolar transistor 3 is turned off, the DC power source 10, the resistor 7, the bipolar transistor 2, the resistor 4, the capacitance 1 between the gate G and the emitter E of the IGBT 1
a, a current flows I _G in the loop of the DC power source 5. This current I _G, stray capacitance 1a between the gate G- emitter E of IGBT1 is charged to the positive polarity, IGBT1 gates G
The voltage V _GE between the emitter E rises from the reverse bias voltage (−5 V) of the DC power supply 5 to 15 V which is a composite value of the output voltage (20 V) of the DC power supply 10 and the output voltage (−5 V) of the DC power supply 5.

During the rising process, the IGBT
The voltage VGE between the gate G and the emitter E of the threshold voltage _V.sub.1 is equal to the threshold value _V.sub.th.
(At about 5 V) (time t _d ), the IGBT 1
Start the turned on, a current I _c is energized. In this case, the bipolar transistor 2 is turned on by 100n.
Since the voltage V _GE between the gate G- emitter E of IGBT1 with takes about s is only applied up to 15V with a relatively low voltage, IGBT1 requires several 100ns to turn. As a result, the rise of the energization current I _c of IGBT1 is assumed slower than 60ns necessary pulse laser.

[0012]

A thyratron is used as a main switch of a power supply of a pulse laser such as an excimer laser or a copper vapor laser. However, the thyratron is a kind of vacuum tube and has a relatively short life of about 10 ⁹ shots. Therefore, in recent years, a longer life has been studied by using a main switch as a semiconductor (commonly called a solid state device).

In the pulse laser, a large current pulse having a sharp rise such as a rise time of 60 ns and a peak value of 3000 A is supplied to the thyratron. From this, it is considered that a MOS-bipolar composite device represented by IGBT having both the high-speed switching property of the FET and the high conductivity of the bipolar element is suitable as a switching element applied to a main switch of a pulse laser.

[0014] To apply the IGBT1 in the main switch of the pulsed laser, the rise time of the thyratron current supplied above the voltage V _GE to a positive polarity of a predetermined voltage between IGBT1 gates G- emitter E due to fast turn the IGBT1 It is necessary to start up in less than 60 ns.

Therefore, the actual capacitance 1a between the gate G and the emitter E per chip of the IGBT 1 is 60
Assuming 00PF, in the conventional drive circuit of the IGBT shown in FIG. 5, when the voltage V _GE between the gate G and the emitter E per one chip of the IGBT 1 rises from −5 V to 15 V in 60 ns, the bipolar transistor 2
When estimate the magnitude of the current I _G to be _{energized, I G = 6000PF [15V -} (- 5V)] / 60ns = the 2A.

In general, the turn-on time of a bipolar transistor is shorter as the capacity is smaller. However, at a rated current of 2 A, the turn-on time of a high-speed switching type bipolar transistor is about 100 ns. Therefore, I
In the conventional drive circuits using bipolar transistors 2 to the first switching element for passing a current I _G to charge the capacitance 1a between the gate G- emitter E of GBT1, gate G- emitter of IGBT1 Since the voltage V _GE between E does not rise faster than the predetermined time of the thyratron conduction current up to the predetermined voltage of the positive polarity, the IGBT 1 cannot be switched at a high speed.

In addition, a bipolar transistor having a small capacity such as a rated current of 100 mA has a turn-on time as short as 25 ns. In this case, the bipolar transistor 2 is used to supply a predetermined amount of current.
Must be connected in parallel, and the number of components used increases, resulting in a problem that reliability is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been developed for a pulsed laser in 60 ns.
It is an object of the present invention to provide a highly reliable drive circuit that can turn on a MOS-bipolar composite device represented by an IGBT at a high speed so that a pulse current having an extremely short rise time can be obtained, and that can minimize the number of components. Aim.

[0019]

Means for Solving the Problems A drive circuit according to this inventions comprises a first switching element for passing a current for charging the capacitance between the Geto cathode MOS- bipolar composite element, the first A second switching element connected in series to the switching element of the above and provided between the gate and the cathode of the MOS-bipolar composite element, and the first and second switching elements are alternately switched based on an external drive signal. By turning on and off the MO
In a drive circuit comprising a receiving circuit for performing a switching operation of an S-bipolar composite device, the first switching device is a P-channel type F-type transistor having a cathode terminal connected to the gate of the MOS-bipolar composite device.
ET , and the second switching element is
The pole side terminal is connected to the gate of the MOS-bipolar composite device.
The receiving circuit is constituted by N-channel type FETs connected, and the receiving circuit generates two drive signals having different reference potentials from the drive signals by using a photocoupler, and the first switching element is formed by one drive signal. And driving the second switching element with the other drive signal to produce the MOS-bipolar composite element.
The voltage applied between the gate and the cathode of the first switch is
In this configuration, the withstand voltage between the gate and the anode of the chucking element is made larger .

Further, one end connected to the anode side terminal of the first switching element, the other end is that further comprising a capacitor connected to the cathode of the MOS- bipolar composite element.

Further, the above MOS-bipolar composite device
Are connected in parallel, and the first switching element
Indicates a plurality corresponding to the number of the MOS-bipolar composite elements.
Connected in parallel, and the MOS-bipolar
And one end of each of the first elements is provided.
Connected to the anode side terminal of the switching element
A plurality of MOS-bipolar composite devices connected to a cathode;
It is provided with a plurality of capacitors .

[0022]

The MOS-bipolar composite device represented by the IGBT has a gate G-emitter E voltage (in the case of an IGBT) or a gate G-cathode k voltage (MOS
The thyristor has a characteristic that the turn-on becomes faster as the rise of the thyristor becomes faster and the voltage thereof becomes larger. Drive circuit definitive in this inventions are, MO
The first switching element for supplying a current for charging the capacitance between the gate and the cathode for turning on the S-bipolar composite element is a P-channel type F-type switching element.
ET is applied, and the rising time of the thyratron conduction current is 60 ns due to the high-speed switching characteristic of the FET which is a majority carrier device even when a current of several tens of amperes is supplied.
The voltage between the gate and the cathode of the MOS-bipolar composite device can be raised to a predetermined voltage in a shorter time. Further, the P-channel type FET and the second switching element connected between the gate and the cathode of the MOS-bipolar composite element are driven by two separate drive signals having different reference potentials, and the gate of the P-channel type FET is gated. G-
The gate of the source S Ma耐voltage than MOS- bipolar composite element - to increase the voltage applied between the cathode.

[0023] Also, positive electrode side terminal connected to the anode side terminal of the first switching element, a cathode-side terminal the MO
By providing a capacitor connected to the cathode of the S-bipolar composite element, the voltage between the gate and the cathode of the MOS-bipolar composite element rises at a high steepness and is turned off at high speed.

Further, the above MOS-bipolar composite device
Is the drive circuit connected in parallel
The first switching element is a MOS-bipolar composite.
A number of devices are connected in parallel according to the number of elements.
Provision is made according to the number of MOS-bipolar composite devices.
And one end is connected to the anode of each of the first switching elements.
Terminal and the other end is the above MOS-bipolar composite element.
Having multiple capacitors connected to the cathode of the child
Can respond .

[0025]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 15 denotes a drain D
The P-channel type FET 16 as a first switching element connected to the gate G of the GBT 1 has a drain D connected to the gate G of the IGBT 1 via a resistor 18 and a source S connected to the emitter E of the IGBT 1. N-channel type FE as a second switching element
T and 17 have both terminals charged to a predetermined voltage (30 V),
A capacitor whose anode terminal is connected to the source S of the P-channel type FET 15 as the first switching element, and whose cathode terminal is connected to the emitter E of the IGBT 1.

Reference numeral 19 denotes an external drive signal P _S
Receiving circuit for driving a P-channel type FET 15 as a first switching element and an N-channel type FET 16 as a second switching element, an IC 20 for inverting and outputting an input signal V ₂ , 21 capacitor provided in the vicinity of the IC20 for stabilizing the power supply voltage E ₁ supplied from the DC power supply 29, IC 22 is the inverted output of the input signal V _1, 23 is a power supply voltage E supplied from the DC power supply 29 ₁ (= 15V) is a capacitor provided near the IC 22 to stabilize it.

Further, 24 converts the optical drive signal P _S which is transmitted from the outside via the optical fiber 27 into an electric signal, an optical receiver for inverted output, 24a denotes an optical fiber 2
Receiving diode optical drive signal P _S to be transmitted via a 7 is inputted as a low impedance, 24b drives a bipolar transistor 24c of the detection to NPN junction that receiving diode 24a becomes a low impedance IC , 24d are shields for electromagnetically shielding the optical fiber 27 and the light receiving diode 24a.

Reference numeral 25 denotes a capacitor provided near the optical receiver 24 for stabilizing the power supply voltage E ₂ (= 5 V) supplied from the DC power supply 28. Reference numeral 26 denotes an optical receiver 24 to which no optical drive signal is input. NPN provided in
When the junction transistor 24c is off, I
C22 of the input signal supply voltage V ₁ is supplied from the DC power source 29 E ₁ (= 15V) equally of (inverted output) anode of a DC power supply 29 to the NPN junction transistor 24
c is a resistor connected between the collector C and the collector C.

Reference numeral 30 denotes an IC for inverting and outputting the input signal V _4, and reference numeral 31 denotes a power supply voltage E ₃ supplied from a DC power supply 36.
Capacitor provided in the vicinity of the IC30 for stabilizing the (= 15V), 32 inputs the drive signal V ₂ obtained by inverting the output of the IC 22, the drive signal V ₂ and electrically drive signal V ₄ which is insulated photocoupler for generating, 32a is a light emitting diode for converting the optical drive signals drive signal V ₄ in the photo-coupler 32, 3
2b receives the optical drive signal and outputs the drive signal V ₄
Is a shield for electromagnetically shielding between the light emitting diode 32a and the light receiving element 32b.

Reference numeral 33 denotes a capacitor provided near the photocoupler 32 for stabilizing the power supply voltage E ₃ (= 15 V) supplied from the DC power supply. Reference numeral 33 denotes a power supply voltage E supplied from the DC power supply 36. ₃ (= 15V) is provided in the vicinity of the photocoupler 32 for stabilizing the light emitting diode 32a. The capacitor 34 is provided for preventing the reverse overvoltage from being applied to the light emitting diode 32a.
The diode 35 is connected in anti-parallel to
₂ is a resistor for suppressing a current supplied to the light emitting diode 32a.

Next, the operation will be described with reference to FIG. 2 showing the operation waveform of each part. First, when no external IGBT drive signal (optical signal P _S ) is input, the inverted output V ₁ of the optical receiver 24 becomes the voltage E ₁ (= 15 V) supplied from the DC power supply 29, so the inverted output V ₁ is output. inverted output V ₂ of the IC22 for inputting ₁ zero, the inverted output V ₃ of the IC20 for inputting the inverted output V ₂ is a voltage E ₁ supplied from the DC power source 29 (15V).

Therefore, the P-channel type FET 15
Is connected to the anode side of the DC power supply 29, the gate G and the source S of the P-channel type FET 15 are at the same potential, no voltage is applied between them, and the P-channel type FET 15 is turned off. .

Further, in the inverted output V ₂ is zero IC 22, the current I _d is not energized via the resistor 34, light emitting diode 32a does not output the light, as a result, the light receiving element 32
No light is input to b, the output V _{4 of the} photocoupler 32 becomes zero, and the inverted output V ₅ of the IC 30 that receives the output V ₄ becomes the voltage E ₃ (= 15 V) supplied from the DC power supply 36.

Therefore, the N-channel type FET 16
Is connected to the cathode side of the DC power supply 36, the voltage E ₃ (= 15) supplied from the DC power supply 36 between the gate G and the source S of the N-channel type FET 16
V) is applied, and the N-channel type FET 16 is turned on.

Since the P-channel type FET 15 is off and the N-channel type FET 16 is on, a resistor 2 is connected between the gate G and the emitter E of the IGBT 1.
6, and the voltage _VGE is not applied during this time. Therefore, IGBT 1 is in OFF state, no current flows I _c in the IGBT 1.

Next, at time t ₁ shown in FIG. 2, when an IGBT drive signal P _S (optical signal) is transmitted from the outside to the optical receiver 24 via the optical fiber 22, the inverted output V ₁ is output at time t _1. Delay time d inherent to optical receiver
Becomes zero only ₁ late in time t _2.

When the zero inverted output V ₁ is input to the IC 22, the inverted output V ₂ of the IC 22 changes from the time t ₂ to the IC 22.
At time t ₃ , the power supply voltage E ₁ (= 15 V) supplied from the DC power supply 29 is delayed by the delay time d ₂ inherent to 22.
The inverted output V ₂ which at the supply voltage E ₁ is inputted to the IC 20, the inverted output V ₃ of Ic20 from time t ₃ IC1
6 the inherent delay time d ₃ delayed zero to time t ₄ in.

Since the source S of the P-channel type FET 15 is connected to the anode side of the DC power supply 29, when the zero inverted output V ₃ is input to the gate G of the FET 15, the gate G-source of the FET 15 between S will be the power supply voltage E ₁ is supplied from the DC power supply 29 (= 15V) is applied in the direction in which the gate G potential is lower than the source S potential, FET 15 from the time t ₄ FET 15 unique to turn on at a time t ₈ delayed by a delay time d _7.

On the other hand, at time t ₃ , the inverted output V ₂ of IC 22
Becomes equal to the power supply voltage E ₁ (= 15 V), the current I _d is supplied via the resistor 35 to the light emitting diode 32 in the photocoupler 32.
a, and the light emitting diode 32a outputs light.
When the light is input to the light receiving element 32b, from time t ₃ by the photocoupler 32 inherent delay time d ₄ delay time t
₅ , the output V _{4 of the} photocoupler 32 becomes the power supply voltage E ₃ (= 15 V) supplied from the DC power supply 36.

[0040] When the power supply voltage E ₃ to time t ₅ (= 15V) and the output V ₄ became are input to IC30, IC30 inverted output V ₅ of delay time specific d ₅ only at time t ₆ late IC30 is It becomes zero. Inverted output V ₅ to the time t ₆ becomes zero
Is input to the gate G of the N-channel type FET 16, since the source S of the FET 16 is connected to the cathode of the DC power supply 36, the gate G-source S
The inter-voltage becomes zero, and the FET 16 starts to operate as the FET ₁ from the time t _6.
6 only inherent delay time d ₆ delay turning off at a time t ₇ in.

The time t _{7 at} which the N-channel type FET 16 is turned off due to the delay time d ₄ inherent to the photocoupler 32 is later than the time t _{8 at} which the P-channel type FET 15 is turned on. Therefore, there the FET16 is turned on in the N-channel type at time t ₈ FET 15 is turned on the P-channel type, the DC power supply 29, the DC power source 36, P-channel type FET1
5, a current (not shown) flows through the loop of the resistor 18, the N-channel type FET16.

However, since this current is suppressed by the resistor 18, there is no problem and the gate G-
At time t ₈ in FET16 still on-state of the N-channel type between the emitter E, the DC power source 29, a current I _G is supplied from the capacitor 17 which is charged by the power supply of the DC power source 36, gate G- emitter of IGBT1 Since the capacitance 1a between E is rapidly charged, IGB
The voltage V _GE between the gate G and the emitter E of T1 is the DC power supply 2
9. The power supply voltage (E) supplied from each power supply of the DC power supply 36
₁ + E ₃ = 30V).

In the course of the rise of the voltage V _GE between the gate G and the emitter E of the IGBT 1 from time t ₈ , the IGBT 1 starts to turn on at a time (time t ₉ ) at which the threshold value (about 5 V) is exceeded, and the current I _c Is energized.

In this case, the FET 15 requires only several tens of ns to turn on due to the high-speed switching characteristic of the majority carrier device. Moreover, when the capacitor 17 is P
Source S of channel type FET 15 and IGBT 1
Connected to the emitter E of the IGBT 1
Not from the DC power supply 29 located far from
Results in the current I _G is supplied from the capacitor 17 provided in the vicinity of the BT1, current loop current I _G is supplied an extremely low inductance.

[0045] From these facts, the rise of the DC I _G becomes extremely KoTakashido, that the voltage V _GE between the gate G- emitter E of IGBT1 very KoTakashi degree between FET15 gate G- source S of the P-channel type It rises to 30V, which is higher than the withstand voltage (generally 20V). From the above, 60 ns required for the pulse laser can be obtained at the rise of the conduction current I _C of the IGBT 1.

In the above embodiment, the capacitor 17 is provided near the IGBT 1 in order to turn on the IGBT 1 very quickly.
It supplies a current I _G to charge the capacitance 1a between the gate G- emitter E of T1.

However, even if the capacitor 17 is not provided, the P-channel type FET, which is a majority carrier device, has high-speed switching characteristics, so that the DC power supply 36, the DC power supply 29, the P-channel type FET 15, By arranging these components close to each other so as to reduce the inductance of the loop of the IGBT 1 and increasing the width of a current path for electrically connecting these components, a steep rise from the DC power supplies 36 and 29 is achieved. current supply, the IGBT1 to fast turn launched a gate G- emitter E voltage V _GE of IGBT1 in KoTakashido, it is sufficiently possible to obtain a 60ns necessary pulse laser as the rise of the energizing current IC.

Embodiment 2 FIG. In the first embodiment, the drive circuit in the case of one IGBT 1 is shown. However, as shown in FIG. 3, a plurality of IGBTs 1b, 1
The drive circuit in the case of c, 1d, 1e is IGBT1
b, 1c, 1d, to reduce the total inductance of the loop current I _G flows to charge the capacitance 1a of between the gate G- emitter E of 1e, a plurality of P-channel type as the first switching element FET 15a,
15b, 15c, 15d and a plurality of capacitors 17a,
17b, 17c and 17d may be provided.

In the pulse laser, the pulse repetition cycle is, for example, 200 μs, which is longer than the rise time (for example, 60 ns) of the pulse current supplied to the main switch of the pulse laser, and the turn-off of the main switch may be later than the turn-on. When the IGBTs 1b, 1c, 1d and 1e are turned off, the second switching element connected between each gate G and the emitter E has only one N-channel type FET 16 as in the first embodiment of FIG. .

Although the IC 20 is used to drive one P-channel type FET 15 in the first embodiment of FIG. 1, four P-channel type FETs 15a, 15b, and 15 are used in the second embodiment of FIG. 15c and 15d, a P-channel type FET 37 and an N-channel type F
ET38 is used. Further, a resistor 39 is provided to prevent an overcurrent from being supplied from the DC power supply 29 to the P-channel type FET 37 and the N-channel type FET 38 when both are transiently turned on. ing.

In the case of an IGBT of a so-called discrete type package 40 as shown in FIG.
The emitter terminal 43 is the main current I _c for energizing the drive voltage V
It is not separated from the one for _GE application and only one is provided.

Therefore, when the output line of the drive circuit connected to the emitter E side of the IGBT is connected to the emitter terminal 43 at a position distant from the package, the IGBT is turned on, and a pulse of a sharp rise (di / dt) is applied to the IGBT. When the current I _c flows voltage drop due to the inductance 2 L (dI _c / dt) is generated with the emitter terminal 43, sufficient voltage is not applied between the gate G- emitter E of the IGBT in the package 40, as a result, IGBT Turn-on may be delayed.

When the pulse current I _c reaches the peak value and rapidly decreases, dI _c / dt becomes negative, so that the voltage increases, and the voltage increases between the gate G and the emitter E of the IGBT in the package 40. There is a fear that a voltage higher than the withstand voltage is applied and the IGBT breaks down. In FIG. 4, reference numeral 41 denotes a gate terminal, and reference numeral 42 denotes a collector terminal.

From these facts, when the IGBT of the discrete type package 40 is applied to the main switch of the pulse laser power supply, the output line of the drive circuit connected to the emitter is connected to the emitter terminal 43 at a position as close to the package 40 as possible. There is a need to. It should be noted that practically, it is sufficient that the distance is within 5 mm from the package.

[0055]

As is evident from the foregoing description, according to the inventions, FET that fast switching can be obtained as compared with a bipolar transistor conduction current even tens A (P-channel type)
Is applied to a switching element for supplying a current for charging a capacitance between its gate and cathode to turn on a MOS-bipolar composite element, and a drive signal transmitted from the outside to a drive circuit using a photocoupler. In this case, two signals having different reference potentials are generated, and the FET is driven by one of the two signals.
The voltage is applied between the gate and the cathode of the bipolar composite device at a rising time faster than in the conventional drive circuit. As a result, M
There is an effect that an ultra-high-speed turn-on of 60 ns or less of the OS-bipolar composite element can be obtained. In addition, since an FET can conduct several tens of amperes with one element, the current that can be conducted is 100 mA.
Therefore, the number of components can be reduced as compared with the case of using a small and fast switching bipolar transistor, and there is an effect that a highly reliable drive circuit can be obtained.

[0056] Also, positive electrode side terminal connected to the anode side terminal of the first switching element, a cathode-side terminal the MO
The provision of the capacitor connected to the cathode of the S-bipolar composite device has the effect that the voltage between the gate and the cathode of the MOS-bipolar composite device can be raised at a high steepness and turned off at high speed.

Further, the above MOS-bipolar composite device
Is the drive circuit connected in parallel
The first switching element is a MOS-bipolar composite.
A number of devices are connected in parallel according to the number of elements.
Provision is made according to the number of MOS-bipolar composite devices.
And one end is connected to the anode of each of the first switching elements.
Terminal and the other end is the above MOS-bipolar composite element.
Having multiple capacitors connected to the cathode of the child
Can respond .

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a drive circuit of an IGBT according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of each signal of FIG. 1;

FIG. 3 is a circuit configuration diagram of an IGBT drive circuit according to a second embodiment of the present invention.

FIG. 4 is a discrete type IGBT package.
FIG.

FIG. 5 is a circuit diagram showing a conventional drive circuit of an IGBT.

FIG. 6 is an operation waveform diagram of each signal of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 MOS-bipolar composite element (IGBT) 15 1st switching element (P-channel type FET) 16 2nd switching element (N-channel type FET) 17 Capacitor 19 Receiving circuit 32 Photocoupler

Claims (3)

(57) [Claims] A first device for supplying a current for charging a capacitance between a gate and a cathode of a MOS-bipolar composite device.
A second switching element connected in series with the first switching element and provided between the gate and the cathode of the MOS-bipolar composite element, and the first and second switching elements based on an external drive signal. Second
A receiving circuit for switching the MOS-bipolar composite element by alternately turning on and off the switching elements of the MOS-bipolar composite element. And a P-channel type FET connected to the second switching element.
The anode side terminal of the MOS-bipolar composite device
An N-channel type FET connected to the gate, and the receiving circuit generates two drive signals having different reference potentials from the drive signals by using a photocoupler, and one drive signal is used for the drive circuit. By driving the first switching element and driving the second switching element with the other drive signal, the MOS- bipolar composite
The voltage applied between the gate and the cathode of the
Be larger than the withstand voltage between the gate and anode of the switching element.
Drive circuit, characterized in that configuration and the that. 2. The drive circuit according to claim 1, wherein
Te one end connected to the anode side terminal of the first switching element, a drive circuit for the other end and further comprising a capacitor connected to the cathode of the MOS- bipolar composite element. 3. The drive circuit according to claim 1, wherein
Therefore, a plurality of the MOS-bipolar composite devices are connected in parallel.
The first switching element is connected to the MOS-bar
A number of parallel composite elements are connected in parallel according to the number of
And the number of MOS-Bipolar composite devices
And one end of each of the first switching elements
The other end is connected to the anode terminal of the
The multiple capacitors connected to the cathode of the
Drive circuit, characterized in that it includes.