JPS5849103B2 - Thyristor gate circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gate circuit for a thyristor and a star, and particularly to a thyrisk gate circuit capable of shortening the turn-off time of a thyristor.

Recently, as thylisks have come to be used in higher frequency inverter devices, there has been a demand for cylisks with shorter turn-off times.

Some silices specifically designed and manufactured for this purpose can shorten their turn-off time by applying a reverse voltage between the gate and the cathode.

Figure 1 shows the relationship between the turn-off time of Cyrisk and the voltage between the gate and cathode.From this figure, it can be seen that by applying a reverse voltage between the gate and cathode when turning off Cyrisk, It is understood that the turn-off time can be significantly reduced.

The present invention has been made in view of these points, and it is an object of the present invention to provide a simple and good thyristor gate circuit that can easily shorten the turn-off time of the thyristor.

Embodiments of the present invention will be described in detail below with reference to FIGS. 2 to 5.

FIG. 2 shows a circuit configuration of an embodiment of the present invention. In FIG. 2, 1 is a thyristor, 2 is a first transistor for applying a gate trigger signal to the thyristor 1, and 3 is a thyristor. 1 is a second transistor for applying a reverse voltage between the gate and cathode; 4 is a thyristor 1;
5 is the first DC power supply for applying a gate trigger signal, 5 is the second DC power supply for applying a reverse voltage between the gate and cathode of thyristor 1, 6 is a pulse generator, and γ is the transistor 3's Resistors 8 and 10 for applying a reverse voltage between the base and emitter are rectifier diodes, 9 and 11 are resistors, and the first transistor 2 and the first DC power supply 4 form a first circuit, the second transistor 3, the second
A second circuit is formed by a DC power supply 5, a resistor 9, a rectifier diode 10, and a resistor 11, and a resistor 7 and a rectifier diode 8
The circuit is configured to form a third circuit.

Next, the operation of the Cyrisk gate circuit according to the present invention will be explained with reference to the signal waveforms shown in FIG.

Now, at time t1 shown in FIG.
When a current is supplied to the base of the first transistor 2, the first transistor 2 turns off as shown in FIG.
A current flows through a closed loop consisting of the first DC power supply 4 , the resistor 7 , the rectifier diode 8 , the gate of the thyristor 1 , the cathode of the thyristor 1 , and the first transistor 2 .

At this time, current also flows through the resistors 9 and 11, but by selecting these resistors to be large, this current can be made to a value sufficiently smaller than the current flowing through the closed loop.

When the first transistor 2 is in the on state, the base and emitter of the second transistor 3 are reverse biased due to the voltage drop across the resistor 7 and the rectifier diode 8.
The transistor 3 is in an off state as shown in FIG. 3b.

As a result, a forward voltage as shown in FIG. 3C is generated between the gate and cathode of Cyrisk 1.

Next, at time t2 shown in FIG. 3, when the current of the pulse generator 6 is cut off, the first transistor 2 is turned off as shown in FIG. 3a, and the gate current of the thyristor 1 no longer flows.

Therefore, the reverse bias voltage between the base and emitter of the second transistor 3 due to the voltage drop flowing through the resistor 7 and the rectifier diode 8 becomes zero.

Then, the second DC power supply 5 supplies the resistor 11, the cathode/gate of the thyristor 1, and the emitter/gate of the second transistor 3.
A base current flows to the second transistor 3 through the base, the resistor 9, and the rectifier diode 10, and the second transistor 3 is turned on as shown in FIG. 3b.

Therefore, a reverse voltage is applied between the cathode and the gate of the thyristor 1 as shown in FIG. 3C.

Next, at time t3 shown in FIG. 3, if a signal is applied from the pulse generator 6 to the base of the first transistor 2 to turn it on, a current is applied to the gate of the thyristor 1 in the same manner as described above, and the first transistor 2 is turned on. The second transistor 3 is turned off.

Therefore, a forward current is applied to the gate of the cyrisk, and no reverse voltage is applied.

Therefore, by turning on and off the first transistor 2, a forward voltage and a reverse voltage can be applied between the gate and cathode of the thyristor 1 as shown in FIG. 3C.

FIG. 4 shows operating waveforms when the thyristor gate circuit according to the present invention is applied to an inverter circuit. The current and anode voltage waveforms are shown, and FIG. 4C is the voltage waveform applied between the gate and cathode of the thyristor.

During the time t1 to t1 shown in FIG. 4, the first transistor 2 shown in FIG. 2 is on and the second transistor 3 is off, and during the time t1 to tl4, the first transistor 2 is off.
The second transistor 3 is on.

In this way, at time t1, the first transistor 2 is turned on, thereby applying the Cyrisk gate trigger signal.

At time t1, the second transistor 3 is turned on, thereby applying a reverse voltage between the gate and cathode of the thyristor, thereby achieving the effect of shortening the turn-off time as described above.

In Fig. 4, the period during which the reverse voltage is applied between the anode and cathode of the Cylisk is from tl2 to tl3, but if this period is made longer than the turn-off time of the Cylisk, this inverter circuit will operate safely. do.

FIG. 5 shows a circuit configuration of another embodiment of the present invention, and the difference from the embodiment of FIG. 2 is that the second transistor 3, in which the PNP type was used in FIG. Due to the use of transistors, they are almost the same except for the accompanying change in component arrangement, so a description of their operation will be omitted.

As is clear from the above description, according to the present invention, the turn-off time of the Cyrisk can be easily shortened by being configured such that a reverse voltage can be applied between the gate and cathode of the Cyrisk when the Cyrisk is turned off. This makes it possible to obtain a simple and high performance Sirisk gate circuit that can be used even in the high frequency range.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the characteristics of Cyrisk's gate-cathode voltage versus Kuhn-off time, Fig. 2 is a circuit configuration diagram showing an embodiment of the present invention, and Fig. 3 is a signal waveform to explain Fig. 2. FIG. 4 is a signal waveform diagram showing the operation of Cyrisk when the present invention is applied to an inverter circuit, and FIG. 5 is a circuit configuration diagram showing another embodiment of the present invention. In the figure, 1 is Cyrisk, 2 is the first transistor, 3 is the second transistor, 4 is the first DC power supply, 5 is the second DC power supply, 6 is the pulse generator, 7, 9, and 11 are resistors. , 8
．． 10 is a rectifier diode. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first circuit that connects a first transistor turned on by a pulse generator and a first DC power supply in series between the gate cathode of the thyristor and applies a forward voltage to the thyristor as a gate trigger signal; , a second circuit that connects a second transistor that is turned on when the first transistor is turned off and a second DC power supply in series between the gate cathode of the cyrisk, and applies a reverse voltage to the thyrisk; The second transistor is connected between the pace emitters of the second transistor, and when the first transistor is turned on, a forward voltage is applied to the silicon risk as a gate trigger signal, while the second transistor is turned off to suppress the application of a reverse voltage. and a third circuit consisting of a series connection of a rectifying diode and a resistor.