JPH0961905A - Gate driving circuit of insulated gate type bipolar transistor and stroboscope having this driving circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stroboscope capable of outputting light emission waveforms without the occurrence of unequal luminance by providing this device with a gate driving circuit of an insulated gate type bipolar transistor having specific constitution and effect. SOLUTION: The transistor(TR) 4 of a first control element is controlled to an on-state and the transistor(TR) 5 of a second control element to an off- state when a control circuit 7 operates and a low level signal is outputted from its output terminal 7a, by which a power source Vg for driving is impressed on the gate of the insulated gate type bipolar transistor (I.G.B.T.) 2 via a first resistance element 12. The I.G.B.T. 2 is then put into the on-state and a flash discharge tube 1 emits light. On the other hand, the TR 4 is controlled to the off-state on the contrary from the previous case when the control circuit 7 operates and a high level signal is outputted from its output terminal 7a. The supply of the power source Vg for driving to the gate of the I.G.B.T. 2 to which this power source is supplied thus far is stopped and the light emission of the flash discharge tube 1 is stopped.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated gate bipolar transistor (hereinafter simply referred to as I.G.B.) which is connected in series with a flash discharge tube in order to control the light emitting operation of the flash discharge tube.
(Hereinafter referred to as “T.”) and a strobe device equipped with the gate drive circuit for driving the gate drive circuit on and off.
The present invention relates to a gate drive circuit that can be driven off and a strobe device that includes this drive circuit and can realize stable high-speed repetitive light emission operation.

2. Description of the Related Art Conventionally, a gate drive circuit for turning on / off an IGBT for controlling a light emitting operation of a flash discharge tube and a strobe device equipped with this drive circuit are well known and specifically 4 is well known, for example, as shown in FIGS. 4 (a) and 4 (b). . The I.G. shown in FIG. 4A, which is connected in series with the flash discharge tube 1 to control the light emitting operation of the flash discharge tube 1.
The BT. 2 gate drive circuit 3 includes a transistor 4, which is two switching elements connected in series between a driving power supply Vg for driving the I. G. B. T. 2 and the ground.
5, the connection point between the transistors 4 and 5 and IGBTT2
And a resistor 6 connected between the gates of the. Further, an output terminal 7a connected to the bases of the transistors 4 and 5 is provided, and by outputting a low level or high level signal from the output terminal 7a, on / off control of the operations of the transistors 4 and 5 is complementarily performed. Control circuit 7
It is comprised including. 4 having the same reference numerals as those of the configuration shown in FIG.
The IGBT2 gate drive circuit 8 shown in FIG.
A transistor 4, a resistor 10, and a transistor 5 are connected in series, and a series connection body 9 connected between the driving power source Vg and the ground and a control circuit 7 for complementary ON / OFF control of the operations of the transistors 4 and 5. It consists of and. In addition, the gate of IGBTT2 has the above resistance 10
Is connected to the connection point of the transistor 5. Therefore, when the control circuit 7 operates and a high-level signal is output from its output terminal 7a, the transistors 4 shown in FIGS. 4A and 4B are both turned on and the transistor 5 is turned on. Both will be controlled to the off state. When the transistor 4 is turned on, the gate drive circuit 3 of the former is connected via the resistor 6 and the gate drive circuit 8 of the latter is connected.
, The driving power source Vg is IG through the resistor 10.
It is applied to the gate of B.T.T.T.2, which turns on the I.G.B.T.2. At this time, by operating a well-known trigger means (not shown) or the like, the flash discharge tube 1 consumes the charge of a well-known main capacitor (not shown) and emits light.
The apparatus shown in (a) and (b) is also configured in this way. On the other hand, when the control circuit 7 operates and a low level signal is output from the output terminal 7a thereof, contrary to the above case, as shown in FIG.
The transistors 4 in (a) and (b) are both turned off, and the transistor 5 is turned on. When the transistor 4 is turned off, the driving power source V to the gate of the IGBTT 2 which has been used until then is used.
The supply of g is stopped, and the transistor 5
Is turned on, through the resistor 6 in the former gate drive circuit 3 and directly in the latter gate drive circuit 8,
The gate of the IGBTT2 is connected to the ground, and the IGBTT2 is turned off. IGBTT
When 2 is turned off, the discharge current that has been flowing through the flash discharge tube 1 is cut off, and the flash discharge tube 1 stops its light emission. Next, for reference, the gate drive circuit 3 shown in FIGS.
The operation of the gate drive circuits 3 and 8 and the light emitted from the flash discharge tube 1 when 8 is driven at a high cycle will be briefly described. 5A and 5B, for example, the frequency from the output terminal 7a of the control circuit 7 is 50 KHz,
FIG. 3 is a schematic emission waveform diagram schematically showing light emitted from the flash discharge tube 1 when a pulse signal having a duty ratio of 1 is output for a predetermined period T. Similarly, FIG.
(A), (b), (c), FIG. 7 (a), (b), (c)
Is an appropriate portion during the above operation, that is, the output terminal 7a (point X) of the control circuit 7 during the above operation,
It is a signal waveform diagram which showed typically the signal in the gate (Y point) of IGBTT2, and the collector (Z point) of IGBTT2. Note that FIG. 6 is FIG. 4 (a), and FIG. 7 is FIG. 4 (b).
It corresponds to the gate drive circuit 8 shown in FIG. FIG.
As is clear from (a) and (b), the flash discharge tube 1 responds to the pulse signal having the above-mentioned characteristics output from the output terminal 7a of the control circuit 7 to perform high-speed repetitive light emission operation for a predetermined period T. Is going. In addition, the IGBT2 corresponding to each light emitting operation during the above high-speed repetitive light emitting operation
Although the operations such as are clear from FIGS. 6 and 7,
When the IGBT2 is driven at a high cycle as described above, its on / off operation characteristic is that the IGBT2 has its gate-emitter gate and gate. ~ It is apparent that it is largely controlled by the charging and discharging operations of the stray capacitance component between the collectors. That is, in the drive circuit 3 shown in FIG. 4A, as shown in FIG. 6A, the output terminal 7a of the control circuit 7 at an appropriate time t1.
When the signal output by is inverted from the low level signal to the high level signal, that is, when the point X in the drawing is changed from the low level to the high level, the transistor 4 as the switch element is turned on and the transistor 5 is turned on. The reversing operation is performed in the off state. When the transistor 4 turns on, the IGBTT2
The driving power source Vg is applied to the Y-gate, which is the gate of the IGBTT2, through the resistor 6, and as a result, as shown in FIG. As the charging operation is performed, the potential at the above-mentioned point Y rises, so that FIG.
As shown in (c), for example, at the time point 2, IGB.
T.2 is turned on, that is, the potential at point Z decreases. When the IGBTT 2 is turned on, the charging voltage of the main capacitor 2 is applied to the flash discharge tube 1, and the flash discharge tube 1 consumes the charge of the main capacitor 2 and emits light. . The output terminal 7 of the control circuit 7 at an appropriate time t3.
When the signal output by a is inverted from the high level signal to the low level signal, that is, when the point X in the drawing is changed from the high level to the low level, the transistor 4 as the switch element is turned off and the transistor 5 is turned on. Are in the ON state, and the reverse operation is performed. When the transistor 4 is turned off, the driving power source V
Since the application of g to the previous Y point is stopped, FIG.
As shown in FIG. 6, the discharge operation of the above-mentioned stray capacitance component is started from the time point t3, and the potential at the above-mentioned point Y is lowered, and as shown in FIG. 6C, for example, at the time point t4, the I.G.B. .T.2 is turned off, that is, the potential at point Z rises. When the IGBTT2 is turned off, the discharge current of the flash discharge tube 1 is cut off, so that the flash discharge tube 1 stops its light emission. The drive circuit 8 shown in FIG. 4B also has an appropriate time t1 as shown in FIG. 7A.
When the signal output from the output terminal 7a of the control circuit 7 is inverted from the low level signal to the high level signal at time t3 and from the high level signal to the low level signal at time t3, that is, the point X in the drawing changes from low level to high level. When the level is further changed from the high level to the low level, the transistors 4 and 5 which are the switching elements perform the inversion operation in response to the potential at the point X, as in the previous case. Therefore, the IGBTT 2 and the flash discharge tube 1 also perform the reversing operation and the light emitting operation similar to the above case. It is to be noted that the driving circuits 3 and 8 shown in FIGS. 4A and 4B have different circuit configurations for performing the charging operation and the discharging operation of the stray capacitance component of the IGBTT2. Needless to say, that is, both the charging and discharging operations of the above-mentioned stray capacitance component in the drive circuit 3 shown in FIG. 4A are performed via the resistor 6, while those shown in FIG. In the charging and discharging operations of the floating capacitance component in the driving circuit 8, the charging is performed through the resistor 10 and the discharging is performed without passing through the resistor 10. Therefore, the drive circuit 3 shown in FIGS.
8, the charge operation and the discharge operation characteristic of the IGB T2 stray capacitance component are substantially the same as the charge characteristic, but the discharge characteristic is the drive circuit 8 shown in FIG. Therefore, the structure of has a more steep discharge characteristic.

As described above, FIG.
Conventional gate drive circuits 3 and 8 shown in FIGS.
Can control the on / off operation of the IGBTT2, and when applied to a strobe device, the light emitting operation of the flash discharge tube 1 is turned on / off of the IGBT2. It can be controlled in response to the control of the off operation. The strobe device of the type that controls the light emission operation of the flash discharge tube by the on / off operation of the IGBTT, unlike the conventional device of the type that uses a thyristor as the element for light emission control, Since a commutation circuit including a capacitor is not required for the GBT off operation, the next light emission operation can be started after an extremely short time, and other advantages are provided in comparison with the above conventional device. It has been known. However, in order to realize, for example, stroboscopic light emission photographing at a high shutter speed, or confirmation of the state of the subject to be photographed, in the configuration shown in FIGS. 4A and 4B, substantially constant light emission is achieved. In order to obtain a light emission waveform that has intensity and a relatively long duration, that is, to obtain a light emission waveform that can be regarded as continuous light emission, when the flash discharge tube performs high-speed repeated light emission operation, There is a risk of inconvenience. That is, regarding the state confirmation of the subject by the light emission obtained by the high-speed repetitive light emission operation as described above, there is no particular problem from the viewpoint of confirmation, but when actually exposing the film with the light emission, the film It was confirmed that there is a case where the disadvantage of uneven brightness occurs in the exposure state of 1. By the way, when the cause of the uneven brightness is examined, FIG.
In (b), the fluctuation amplitudes of the high-speed repetitive emission waveforms indicated by H1 and H2 and the peak amplitudes Hm of the respective emission waveforms, respectively.
It was confirmed that the relationship between 1 and Hm2 contributed to the occurrence of the uneven brightness. That is, the peak amplitudes Hm1, H
Fluctuation amplitudes H1 and H of the high-speed repetitive emission waveform with respect to m2
The larger the ratio of 2 is, the more remarkable the occurrence of the brightness unevenness is. Also, regarding the ratio itself, the characteristics of the on / off operation of the IGBTT, specifically, the above-mentioned IGB. It was also confirmed that the driving energy varies with the supply and non-supply operation characteristics of the gate of T. The present invention has been made in consideration of the above disadvantages and confirmation points,
By performing well-balanced supply and non-supply operations of energy to the above-mentioned gate including the charging and discharging operations of the stray capacitance component existing between the gate and collector of the IGBTT and between the gate and the emitter. , IG above.
It is possible to realize a stable high-speed repetitive light emission operation by including the above-mentioned IGBT gate drive circuit that enables the BT to perform stable high-speed repetitive on / off operation, and this gate drive circuit. Accordingly, it is an object of the present invention to provide a strobe device capable of outputting a light emission waveform without uneven brightness.

SUMMARY OF THE INVENTION IGB according to the present invention.
The gate driving circuit of the T.T. is connected between the gate of the I.G.B.T.T and the power source for driving the I.G.B.T.T, and controls the energy supply operation to the gate. A control element, a second control element connected between the gate and the I.G.B.T.T. collector to control the non-supply operation of energy to the gate, the first control element and the gate, A first resistance element connected between and forming an energy supply circuit to the gate via the first control element;
A second resistance element connected between the second control element and the gate so as not to form the energy supply circuit, and forming a circuit that does not supply energy to the gate via the second control element; Turning on the first and second control elements
And a gate means for performing an off operation. The strobe device according to the present invention is connected in series with a flash discharge tube that consumes the charge of the main capacitor to emit light, and is connected in series with the flash discharge tube to control the light emitting operation of the flash discharge tube.
B.T., the above I.G.B.T.gate and above I.G.B.T.
A first control element connected to the driving power source for driving the gate to control the energy supply operation to the gate, and connected to the gate to the collector of the IGBTT to supply energy to the gate. Second for controlling the non-supplying action of
A control element, a first resistance element connected between the first control element and the gate and forming an energy supply circuit to the gate via the first control element, the second control element and the gate, The second resistance element and the first and second control elements, which are connected so as not to form the energy supply circuit between them, form an energy non-supply circuit to the gate via the second control element, and are turned on. The gate drive circuit of the above-mentioned I. G. B. T.

Since the IGBT gate drive circuit according to the present invention has the above-described structure, it supplies or does not supply energy to the IGBT gate. Is performed through the first and second resistance elements, and in addition,
In such an operation, the second resistance element is connected so as not to form the energy supply circuit, so that the first and second control elements are not directly connected in series. Therefore, the operation of supplying energy and the operation of not supplying energy to the gate of the IGBT can be carried out in an extremely well-balanced and stable manner as compared with the conventional example. Also,
By confirming the phenomenon of the on-off operation of IGBTT, it was confirmed that the variation of the duty ratio of the on-off operation was suppressed. Since the strobe device according to the present invention is provided with the IGBT gate drive circuit having the above-described configuration and operation, the IGBT on / off operation is balanced. It will be good and stable. Also, when the light emitting operation was confirmed, it was confirmed that the ratio of the fluctuation amplitude of the light emitting waveform to the peak amplitude of the above-described high-speed repetitive light emitting operation was suppressed.

1 is a main part electric circuit diagram showing an embodiment of an I.G.B.T.T. gate drive circuit according to the present invention and a strobe device equipped with this drive circuit. Components having the same reference numerals as are functional elements. 11 shows an embodiment of the IGBT gate drive circuit according to the present invention, and FIG.
As is clear from the above, it is connected between the gate of the IGBTT2 and the driving power source Vg of the IGBTT2, and controls the energy supply operation to the gate. The transistor 4 as the first control element, the gate, and the I.V.
A transistor 5 that is a second control element that is connected between the collectors of the GBT2 and controls the non-supply operation of energy to the gate, and is connected between the transistor 4 and the gate. A first resistance element 12 forming an energy supply circuit to the gate via the transistor 4 and the transistor 5 and the gate are connected so as not to form the energy supply circuit, A second resistance element 13 forming a circuit for not supplying energy to the gate and a gate means 7 for turning on / off the transistors 4 and 5 are provided. The operation of the embodiment of the IGBT gate drive circuit according to the present invention and the strobe device equipped with the drive circuit according to the present invention having the above-described configuration will be described below. This is similar to the conventional example described. That is, when the control circuit 7 operates and a low-level signal is output from its output terminal 7a, the transistor 4 as the first control element is turned on and the transistor 5 as the second control element is turned off. The driving power supply Vg is controlled by the IG via the first resistance element 12.
It is applied to the gate of B.T.T.2 and the I.G.B.T.2 is turned on. At this time, by operating the well-known trigger means or the like, the flash discharge tube 1 consumes the well-known charge of the main capacitor and emits light, and of course, the apparatus of this embodiment is also configured as such. On the other hand, the control circuit 7
And a high-level signal is output from its output terminal 7a, the transistor 4 is controlled to be in the OFF state and the transistor 5 is controlled to be in the ON state, contrary to the previous case, and this is done until then. The supply of the driving power supply Vg to the gate of the IGBTT2 is stopped, and at the same time, the transistor 5 is turned on to turn on the IGT via the second resistance element 13.
The gate of BT.2 will be connected to the ground,
Therefore, the IGBTT2 is turned off. In addition, I.G.
When BT.2 is turned off, the discharge current that has been flowing through the flash discharge tube 1 is cut off, and the flash discharge tube 1 stops its light emission. Now, in the present embodiment shown in FIG. 1, similarly to the case where the prior art example is examined, for example, a pulse signal having a frequency of 50 KHz and a duty ratio of 1 is output from the output terminal 7a of the control circuit 7 for a predetermined period T. The case in which the output is performed over will be described. FIG.
Is the flash discharge tube 1 when the present embodiment is controlled as described above.
FIG. 3A, FIG. 3B, and FIG. 3C are schematic emission waveform diagrams schematically showing the light emitted from the light source, and FIG. 3A, FIG. 3B, and FIG. FIG. 7 is a schematic signal waveform diagram schematically showing a signal at point Z, which corresponds to FIG. 5, and FIG. 6 or FIG. 7, respectively. As is clear from FIG. 2, the ratio of the fluctuation amplitude H of the high-speed repetitive light emission waveform to the peak amplitude Hm in the light emission waveform obtained by the strobe device including the IGBT gate drive circuit according to the present invention is as follows. It is suppressed to be smaller than that of the conventional device described at the beginning. Therefore, it is advantageous for the uneven brightness described at the beginning, and when the exposure state of the film when the film is actually exposed by the above-mentioned light emission is confirmed, unlike the conventional apparatus, the uneven brightness does not occur. Was confirmed. Further, as is clear from FIGS. 3A, 3B, and 3C, driving of the IGBT2 gate in the IGBT gate drive circuit according to the present invention. The energy supply operation characteristic and the energy non-supply operation characteristic show almost symmetrical characteristics. That is, Y which is the gate of IGBTT2
The signal waveform of the point gently rises as shown in FIG. 3B and also gently falls with a similar slope. Therefore, the on / off operation of the IGBTT2 is as follows. The same figure (a)
The pulse signal is almost synchronized with the pulse signal shown in (1), in other words, it has a duty ratio substantially equal to the duty ratio of the pulse signal. Now, let us look at the above-described operation of the IGBT gate drive circuit according to the present invention. In the present invention, the first and second resistance elements 12 and 13 independently form the energy supply circuit and the energy non-supply circuit for the gate of the IGBTT2, respectively. Two transistors, which are two control elements, are also connected to each other. Therefore, unlike the above-mentioned conventional circuit, the first and second circuits are inevitably generated during the reversing operation in the high cycle repetitive driving operation.
Even when both of the control elements are turned on, the first and second resistance elements 12 and 13 are connected to the drive power source Vg and the first and second resistance elements 12 and 13.
Transistors 4, 5 or I.G. which are second control elements.
It will exist between the gates of BT2. When such a configuration is viewed centering on the IGBTT2 gate, occurrence of an indefinite control state of the gate potential is suppressed by the first and second resistance elements 12 and 13. Nonetheless, the supply or non-supply of energy to the gate is carried out in good balance. As a result, according to the IGBT gate drive circuit of the present invention, as is apparent from FIG. 3B, the IGBT.
It is possible to suppress the fluctuation of the duty ratio of the ON / OFF operation of No. 2 and thereby to carry out the above-mentioned IGBT2 ON / OFF operation in an extremely well-balanced and stable manner as compared with the conventional configuration. You can do it. Since the strobe device according to the present invention includes the above-described IGBT gate drive circuit, stable high-speed repetitive light-emission operation can be realized when high-speed repetitive light-emission operation is performed. Therefore, it is possible to obtain a light emission waveform in which the ratio of the fluctuation amplitude to the peak amplitude can be suppressed small. That is, the light emission obtained when the flash device according to the present invention performs a high-speed repeated light emission operation is a light emission that does not cause uneven brightness in the exposed state of the film when the film is exposed.

INDUSTRIAL APPLICABILITY According to the present invention, the duty ratio of the on / off operation of the IGBT is achieved by performing the operation of supplying and not supplying the energy to the gate of the IGBT in a well-balanced manner. Of the I.G.B.
This has the effect of providing an IGBTT gate drive circuit that can stably perform high-speed repetitive on / off operation of T.2. Further, the present invention is directed to the first and second control elements for controlling the supply / non-supply operation of energy to the gate of the IGBT which is inevitably generated during the inversion operation in the high cycle repetitive driving operation. Even when both are turned on, the first and second control elements are not directly connected between the driving power supply Vg and the ground, and therefore, there is a risk that the first and second control elements are destroyed. I.G.
It also has the effect of providing a BT gate drive circuit. Further, the present invention provides the IG having the above effects.
By providing a BT gate drive circuit, stable high-speed repetitive light-emission operation can be realized when high-speed repetitive light-emission operation is performed, and thus the ratio of the fluctuation amplitude of the high-speed repetitive light-emission waveform to the peak amplitude in the obtained light-emission waveform. As a result, it is possible to provide a strobe device capable of outputting a light emission waveform that does not cause uneven brightness in the exposed state of the film even when the film is exposed by the light emission obtained by the high-speed repetitive light emission operation. are doing.

[Brief description of drawings]

FIG. 1 is a main part electric circuit diagram showing an embodiment of an IGBTT gate drive circuit according to the present invention and a strobe device equipped with this drive circuit.

2 is a schematic light emission waveform diagram schematically showing a waveform of light emitted when the flash discharge tube in FIG.

FIG. 3 is a schematic signal waveform diagram in FIG.

FIG. 4 (a) is an electric circuit diagram of a main part showing an example of a conventional gate drive circuit for an IGBTT and a strobe device equipped with this drive circuit. Electrical circuit diagram of essential parts showing a conventional example of a gate drive circuit and a strobe device equipped with this drive circuit

5 (a) is a schematic emission waveform diagram schematically showing the waveform of light emitted when the flash discharge tube in FIG. 4 (a) is repeatedly operated to emit light at high speed. (B) FIG. 4 (b) Schematic emission waveform diagram that schematically shows the waveform of the light emitted when the flash discharge tube inside is made to emit light repeatedly at high speed

FIG. 6 is a schematic signal waveform diagram in FIG.

FIG. 7 is a schematic signal waveform diagram in FIG. 4 (b).

[Explanation of symbols]

1 Flash discharge tube 2 Insulated gate type bipolar transistor (IGB.
T.) 3 gate drive circuit 4 transistor (first control element) 5 transistor (second control element) 6 resistance 7 control circuit 8 gate drive circuit 9 series connection body 10 resistance 11 gate drive circuit 12 first resistance element 13 second Resistance element

Claims (2)

[Claims] 1. A first control element connected between a gate of an insulated gate bipolar transistor and a driving power source for the insulated gate bipolar transistor to control an energy supply operation to the gate, the gate and the insulation. A second control element that is connected between the collectors of the gate type bipolar transistors and controls the non-supply operation of energy to the gate, and is connected between the first control element and the gate, and via the first control element. A first resistance element forming an energy supply circuit for the gate, and the second control element and the gate are connected so as not to form the energy supply circuit, and the first resistance element is connected via the second control element. A second resistance element forming an energy non-supply circuit to the gate and the first and second control elements are turned on / off. The gate driving circuit of an insulated gate bipolar transistor and a gate means. 2. A flash discharge tube that consumes the charge of a main capacitor to emit light, an insulated gate bipolar transistor that is connected in series with the flash discharge tube and controls the light emitting operation of the flash discharge tube, and the insulated gate. First control element connected between the gate of the bipolar transistor and the driving power source for the insulated gate bipolar transistor, and controlling the energy supply operation to the gate, between the gate and the collector of the insulated gate bipolar transistor A second control element connected between the first control element and the gate for controlling the non-supply operation of energy to the gate, and an energy supply circuit to the gate via the first control element; The first resistance element to be formed, the energy supply circuit between the second control element and the gate A second resistance element which is connected so as not to be formed and which forms an energy non-supply circuit to the gate through the second control element, and a gate means for turning the first and second control elements on and off. A strobe device having a gate drive circuit for an insulated gate bipolar transistor.