JPS61179614A - Drive circuit of gto - Google Patents

Abstract

PURPOSE:To control a GTO extracting circuit with power saving by using an input signal to activate oppositely a transistor (TR) turning on a GTO and a thyristor turning off the GTO thereby turning on/off surely the GTO by one input signal. CONSTITUTION:A TR52 is turned on when a TR47 is turned on, a capacitor 60 is charged, a current I4 shown in figure (h) flows to a GTO61 as a charging differentiation current to turn on the GTO61. When the TR47 is turned off, the TR52 is turned off, a gate current in shown in figure (f) flows to the thyristor 57 and the electric charge charged in the capacitor 60 is discharged via the thyristor 57. In this case, a reverse current I6 flows as shown in the figure (h) flows to the gate of the GTO61, which is turned off. The operation as above is executed by one input signal E1.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a gate turn-off thyristor (abbreviated as GT).
(referred to as O).

[Technical background of the invention and its problems]

Conventional drive circuits of this type are shown in FIGS. 1 and 2. In the figure, 1 is a terminal connected to the other end of a load whose one end is connected to the main power supply, and 2 is the main 1! 3 is a drive circuit power supply terminal, and 4 is a control signal terminal. 5 is a transistor for on/off control of transistor 7.8, 6 is a bias resistor, 9 to 1 are bias resistors of transistor 7, 12.13 is a bias resistor of transistor 8, 14
．． 15 is the -9ias resistor for GTO 16, 17 is the GTO 16 off capacitor, 18 is the capacitor 17
This is a Zener diode for charging voltage clamp. Transistor 8 is used to turn off GTO 16 by discharging capacitor 17.

In addition, in FIG. 2, 19 is a control photocoupler circuit, 20
is a bias resistor, and 21.22 is a control signal terminal. Further, a resistor 23 and a diode P24 constitute a drive circuit power supply circuit, and a Zener diode 25, a capacitor 26,
The resistor 27 constitutes a constant voltage circuit.

In the GTO drive circuit as described above, the transistor 7.8 is used to turn off the GTO16, but the GT
It is necessary that the negative ti ('r) at turn-off of O has a large peak. The transistor 8 used for this purpose is
I needed something with a high rating. Furthermore, since the r-) negative current varies greatly depending on the anode current of the GTO 16, it is necessary to match the base current of the transistor 80 with the current peak, which has the drawback of increasing the drive power of the drive circuit. In addition, the transistor 5 in the previous stage necessarily needs to have a large capacity, and when attempting to operate at a higher frequency, the transistors 5 and 8 and the power supply capacity become larger. This was done in consideration of the actual situation, and the GTO drive circuit has the advantages of being able to turn on and off the GTO reliably with a single input signal, and controlling the GTO gate extraction circuit with low power consumption. This is what we are trying to provide.

[Summary of the invention]

The present invention operates the on-driving transistor of the GTO and the thyristor for off-driving the GTO in opposite directions using an input signal.
This ensures that the GTO is turned on and off.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
As shown in the figure, the GTO 6J is connected between the input terminal 42 and the output terminal 43 in the forward direction.

A Zener diode 58 is connected to the gate terminal of GTO61.
, a resistor 59 are connected in series, and a capacitor 60 is connected in parallel with the Zener diode 58 and the resistor 59. One of the resistors 48 to 50 is connected to the iK source terminal 44 of the drive circuit, the other terminal of the resistor 50 is connected to the emitter of the transistor 52, and the other terminal of the resistor 49 is connected to the base of the transistor 52. One of the resistors 5 is connected to this base terminal, and the other of the resistors 48 is connected to the other of the resistors 51. The collector of the transistor 52 is connected to the Zener diode 58, the resistor 59, and the capacitor 60.
is connected to the terminal connected in parallel, and further the thyristor 5 is connected to the terminal connected in parallel.
7 anode. The cathode of thyristor 57 is grounded. Further, a resistor 55 and a capacitor 56 are connected in parallel between the gate of the thyristor 57 and the ground. A capacitor 53 and a resistor 54 are connected in parallel between the connecting terminals of the resistors 4g and 51 and the gate of the thyristor 57, the collector of the transistor 47 is connected to this connecting terminal, the emitter of the transistor 47 is grounded, and the gate of the transistor 47 is connected to the connecting terminal. - is grounded via a resistor 46 and the signal input terminal 4
Connected to 5.

Next, the operation of the circuit shown in FIG. 1 will be explained. First, when the voltage E shown in FIG. 3 (el) is applied to the input terminal 45 as a control signal, the transistor 47 is turned on, and as shown in FIG.
If the signal is loud, like the E1 voltage timing of E! There is a voltage, but when it is in the on state, it operates at zero potential. From this hVc, the transistor 52 and the thyristor 57 perform opposite operations. When the transistor 47 is in the OFF state, the current 3 of fl in FIG.
When is in the on state, the base potential of the transistor 520 goes from Ex in FIG. 3(d) to zero potential, so the transistor 52 becomes in the on state and the E4 voltage in FIG. 3(g) is output.

This is clipped by Zener diode 58 and charged into capacitor 60. Therefore, a charge differential current flows through the GTO 61 as shown in FIG. h) current I11 flows.

This turns on the j5 GTO61. Next, when transistor 47 turns off, transistor 5
2 is in the off state, and the gate current shown in FIG. 3 m flows through the thyristor 57. As a result, the charge stored in the capacitor 60 is discharged via the thyristor 57. At this time, the reverse current shown in Figure 3 (h) flows through the gate of GTO61! 6 flows, and GTO 6 is turned off. Such an operation is performed using the input signal E! This can be done with one signal (FIG. 3(C)).

FIG. 2 is an example of an application of the circuit shown in FIG. In other words, this is GT
This is a drive circuit that uses the power supply voltage of O61, uses the Cadera trunk register 19 for input signals, and can completely eliminate the signal system and control system. Since the newly added parts in FIG. 2 correspond to those in FIG. 5, the corresponding parts are given the same reference numerals and the explanation thereof will be omitted.

〔Effect of the invention〕

As explained above, according to the present invention, the GTO can be turned on and off reliably with one signal, and the thyristor is used to draw out the gate negative current depending on the magnitude of the gate negative current when turning off the GTO, and the thyristor is only turned on. Since differential driving is possible, extra drive power is not required, and the circuit can therefore be configured to save power. In addition, by using a high-speed thyristor as the above thyristor,
A drive circuit capable of high-speed switching operation can be provided.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention, FIG. 2 is a circuit diagram of another embodiment of the present invention, FIG. 3 is a signal waveform diagram showing the circuit operation of the above embodiment, and FIG. FIG. 5 is a diagram of a conventional GTO drive circuit. 47.52...Transistor, 4 B, 50,5
1゜54.59...Resistor, 57...Thyristor, 5
8... Zener diode, 60... Capacitor,
61...GTO. Applicant's agent: Patent attorney Takehiko E. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] Connecting to the gate of the GTO one of a circuit in which a Zener diode and a first resistor are connected in series and a circuit in which a capacitor is connected in parallel, and connecting the collector of the first transistor and the anode of the thyristor to the other circuit, The emitter of the first transistor is connected to one electrode of a pivoting power source through a second resistor, the cathode of the thyristor is connected to the other electrode of the driving power source, and the base of the first transistor is connected to the base of the first transistor. One end of a third resistor is connected, and one end of a fourth resistor is connected to the gate of the thyristor, the other ends of the third and fourth resistors are commonly connected, and this common connection is connected to the fifth resistor. A common connection between the third and fourth resistors is connected to the collector of a second transistor, and the emitter of the second transistor is connected to the other electrode of the drive power source through the second transistor. and when no signal is input to the base of the second transistor,
The thyristor is always on, forming an equivalent state in which the gate of the GTO is grounded, and when a signal is input to the base of the second transistor, the base of the first transistor is in an on state, being grounded. The differential current flowing to the gate of the GTO through the capacitor and the current flowing through the Zener diode and the first resistor turn on the GTO, and when the base signal disappears, the thyristor is turned on. and discharge the charging voltage of the capacitor,
A drive circuit for a GTO, characterized in that a negative current flows through the gate of the GTO.