JPS60211981A - Controlling circuit of gate turnoff thyristor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a control circuit for a gate turn-off thyristor.

(Prior Art and Problems) A gate turn-off thyristor (hereinafter referred to as GTO) generally has a large firing current, so it has the disadvantage that the gate circuit becomes large. For example, the withstand voltage is 2500 (V).

To turn off a GTO'i with a cutoff current of 1000 (A) (assuming that a load current of 1000 A is flowing), approximately 800 (4
), but this is not a problem because the turn-off time of the GTO is as short as about 10 (μ). However, in order to turn on the GTO, approximately 80 to 50 (A) is required.
It is necessary to keep the on-gate current i flowing for a long time until the entire junction surface of GTo is turned on. For this reason, there were problems such as the on-gate circuit becoming extremely large. In order to solve such problems, conventionally, a control circuit as shown in FIG. 1, for example, has been used. In FIG. 1, to turn off the main GTO/'i, turn off the switch 6 of the gate control power supply circuit l, turn on the switch, and connect the off-gate DC power supply 7 to the main GTO/'s cathode and gate.
It is sufficient to supply the off-gate current through the loop of + diode Hiro → switch ♂ → DC power supply 7. Main GTO/'i
K, which turns on, supplies an on-gate current to the gate of the auxiliary GTO 2 through gate control, first turning on the auxiliary GTO 2f.

At this time, the main current flowing through the auxiliary GT0.2 is supplied as an amplification gate current to the gate of the main GTO/ through the resistor 3, so that the main GTO/! d Turn on. In the control circuit +d configured in this way, the main current flowing through the auxiliary GTO is all amplified and supplied to the main GTo/, so the on-gate current of the auxiliary 0TO2 is only about 1 (A).
It's enough. Therefore, the configuration of the control power supply circuit 12 can be downsized and simplified. However, in the circuit shown in FIG. 1, if on/off control is frequently performed as in the PWM control, the following open end occurs. That is, when an on-gate current is supplied to the auxiliary GT0.2 and an off-gate current is supplied to the main GTO/ immediately after t (for example, after 10 to 15μ), the voltage of the off-gate DC power supply 7 is increased by the cathode junction of the main GTO/. The auxiliary GTO card junction cannot be reverse biased because it is blocked.

For this reason, the auxiliary GTOλ cannot be turned off, so the corresponding GT
0.2, a large current continues to flow, and as a result, the auxiliary GTOJ is destroyed. Here, in order to ensure that the auxiliary GTOJ is reverse biased, the value of resistor 3 should be increased completely, and the auxiliary GT
There is a method of fully utilizing the voltage drop that occurs across the resistor 3 when the main current of the auxiliary GT02 flows through the anode, cathode, resistor 3, diode 1, and DC power supply 7 of the auxiliary GT02. However, when the value of the resistor 3 is increased as in this method, there is a problem that the on-gate current of the main GTO/ cannot be sufficiently supplied as necessary.

In order to solve the above-mentioned problems, control circuits as shown in FIGS. 2 and 3 have been proposed.

FIG. 2 shows a circuit described in Japanese Unexamined Patent Publication No. 58-118147, which shows the DC power supply 7 for supplying the off-gate current of the main GTO/. DC power supply for on-gate current supply of auxiliary GTO2! In addition, a separate DC power supply is provided for supplying off-gate current to the auxiliary GT0.2. For this reason, there is a drawback that the price of the entire device increases, so please be aware that the circuit shown in Fig. 3 is the circuit described in Japanese Patent Application Laid-Open No. 101461/1982. ) has been replaced with a transistor. For this reason, it is necessary to increase the withstand voltage of the transistor l/, which increases the cost.

(Object of the Invention) The present invention has been made in consideration of the above points, and it is possible to reliably perform on/off control of the main GTO and auxiliary GTO, and to perform on/off control frequently such as AWM control. It is an object of the present invention to provide a control circuit for a gate turn-off thyristor in which an auxiliary GTO is not destroyed due to turn-off failure even if the gate turn-off is performed.

(Summary of the Invention) The present invention is characterized in that a switching control element is inserted between the gate of the main GTO and the cathode of the auxiliary GTO, and the control terminals of the switching control element are commonly connected to the gates of the auxiliary GTO. (Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In FIG. 4, i, , 2/ are main GTOs.

Main GT 0.7. Between the cathode and gate of /, there is a Zener diode (n) and a diode (?) for overvoltage protection with the polarity shown. , I are connected in series. 21I is an auxiliary GT whose anode is connected to the anode of the main GT 0.2/
It is O. The cathode of this auxiliary GT0.24' is connected to the drain of a switching control element, for example a field effect transistor j. This field effect transistor j uses a MO19FEIT with low power consumption, for example, and its source is connected to the gate of the main GT0.2/. A Zener diode with the polarity shown is connected between the drain and source of the field effect transistor 2 to protect the field effect transistor 2. The anode of the diode 27 is connected to the gate of the main GT02/. The cathode of this diode 27, the field effect transistor 2S
and the gate I of the auxiliary GT0.24' are collectively connected to the gate terminal GK. Main GT 0.2
Common connection point 2g between the cathode of / and Zener diode 2
is connected to the auxiliary gate terminal Gk. Between this auxiliary gate terminal Gk and the gate terminal G, there is a series circuit consisting of a DC power supply 7 with the polarity shown and a switch t, and a DC power supply with the polarity shown! A gate control power supply circuit 12 which is connected in parallel with a series circuit including the switch 6 and the switch 6 is connected thereto. In addition, in the figure, the external cathode terminal and A indicate the external anode terminal, respectively. The above circuit is auxiliary G T O2 II
When it is provided on the same Ueno\, it will be constructed as shown in Fig. 5. In FIG. 5, the same parts as in the fourth part are indicated by the same reference numerals, and the explanation thereof will be omitted. Auxiliary GT0.2 is PI
The gate electrode 4 of the auxiliary GTO is formed on the central surface of the 22 layers. / is provided. A cathode electrode 32 of the auxiliary GTO is provided on the surface of the N3 layer on the 1/ concentric circle of this gate electrode. Lord G
TO2/ consists of a P, υ1PtN2 layer provided on the same unit as the auxiliary GT0.24i. Said auxiliary GT
P! on a concentric circle with respect to the gate electrode of 0.21, 7/! Gate electrodes 3Ja and 3Jb of the 1d main GTO are provided on the layer surface as shown in the figure.

The gate electrode of the auxiliary G T O2tI, ? N on a concentric circle with respect to /, the cathode electrode of the main GTO on the layer surface, ?
There are restrictions. It is assumed that the N2 layer and the N3 layer I are formed in a narrow rectangular shape.The Zener diodes u and n shown in FIG. 4 are shown in FIG. 5, and 1 is omitted from the illustration. Please note that a gate control power supply circuit 12 (not shown) is connected between the gate terminal G and the auxiliary gate terminal Gk.Next, the operation of the circuit configured as described above will be described. G
When the anode side of T O2/ is at a positive potential, in order to turn on this main GTOj/'i, first turn off the switch r of the gate control power supply circuit/2 and turn on the switch 6. Then, an on-gate voltage is applied from the DC power supply j to the field effect transistor j via the switch 6, and an on-gate current flows to the auxiliary GT O, y, 4c, so that the field effect transistor J and the auxiliary GT0
．． 211. 'j turn on.

As a result, the main current flowing through the auxiliary G T 0.24 is supplied to the gate of the main G T' 02/ via the drain and source of the field effect transistor J. At this time, the voltage drop that occurs in the field effect transistor j is the main G
T 0.2/, the gate current is amplified and the main G
Flows to the gate of T O2/. By this, the main GT
0.2/ turns on. In this way the main GTO2/
When turned on, the field effect transistor j and the auxiliary GTO;
It does not flow to the main GTO (because the voltage between the anode and cathode of the main GT 0.27 is low).

Therefore, the ionization capacity of the auxiliary G T Oj, 41 and the field effect transistor S can be small. Also, what is the withstand voltage of the field effect transistor 23? is 10-50 Vili low +4
Anything is fine.

Next, to turn off the main GT 04/, first turn off switch 6 and turn off the auxiliary GT 0.241 and 'F.
lf, the on-gate current supply to the W effect transistor 2 is stopped. At this time, the main current flows between the anode and cathode of the main GT0.2/, so the auxiliary GTO2
1fi turns off. Next, switch r-f is turned on and the output voltage of the DC power supply 7 is set to the main G T 0.7! If a reverse bias voltage is applied to the cathode of /, the main GTo2/!
Turn off. At this time, the output voltage of the DC power supply 7 is applied as a reverse bias voltage to the cathode of the auxiliary G T 0.7.4', albeit at a low value, via the anode and cathode of the Zener diode U. This makes the turn-off of the auxiliary GTO 2 more reliable.

Next, when on/off control is frequently performed at high speeds such as PWM control, for example, immediately after supplying the on-gate current i to the auxiliary Ck T 0.211 and the field effect transistor j (while the main GT 0.27 is still turned on). A case will be explained in which an off-gate current is supplied when the off-gate current is not present).

Now switch 6 is turned off, switch Ir is fully turned on, and in the transition period when t, field effect transistor jld is turned off,
Auxiliary GT0.21d is on.

Therefore, the current of auxiliary G T 0.21I is auxiliary G T O
! 4' gate → gate terminal G → switch J' -+
Painting method power supply 7 → lacquered to external cathode terminal. This results in an auxiliary GT of 0.7. Since the cathode junction of II is reverse biased, the auxiliary G T O:ZQ transitions to turn-off. At this time, the output voltage of the DC power supply 7 is also applied to the cathode of the main GTO 0.2/ as a reverse bias voltage, so the main GTO 2/ is also turned off.

Note that the switching control element is not limited to the field effect transistor, and other self-extinguishing switching elements may be used.

(Effects of the Invention) As described above, according to the present invention, a switching control element is inserted between the gate of the main GTO and the cathode of the auxiliary GTO, and the control terminals of the switching control element are commonly connected to the gates of the auxiliary GTO. Just in case, the main GTO and auxiliary GTO
iReliable on/off control. Further, even if on/off control is frequently performed as in PWM control, the auxiliary GTO can be reliably reverse biased, so turn-off failure will not occur.

Therefore, the capacitance of the auxiliary GTO and the switching control element can be reduced, and the cost of the entire circuit can be reduced.

Furthermore, since the time during which the voltage of the control power source is applied to the switching control element is short, the withstand voltage of the switching control element can be lowered, and thereby advantages such as lower costs can be obtained.

[Brief explanation of drawings]

Figures 1 to 3 are circuit diagrams showing conventional control devices, Figures 4 and 6 show an embodiment of the present invention, Figure 4 is a circuit diagram, and Figure 5 is a main GTO and an auxiliary GTO. It is a partial sectional view of a chicken house formed on the same web as GTO'4. t, 7... DC power supply, 4. r...Switch, /2.
・・Gate control power supply circuit, Rika・・Main GTO%u,,
2T... Zener diode, 2J, 27... Diode 1. Comment...Auxiliary GTO, Jj...Field effect transistor 1,? /...Gate electrode 1 of auxiliary GTO,
72...Auxiliary GTO cathode electrode 1.13a, j3
b...Gate electrode of the main GTO, Dedicated...Cathode electrode of the main GTO.

Claims (1)

[Claims] An auxiliary GTO consisting of PI NI P, N3 layer and a large pt Nl layer provided on the same wafer as this auxiliary GTO.
p'aN, a main GTO consisting of a layer, a gate electrode of an auxiliary GTO provided on the surface of the P2 layer in the center of the wafer and supplied with an on-gate current from a control power supply, and a gate electrode concentrically with respect to this electrode. and a cathode electrode of an auxiliary GTO provided on the surface of the N3 layer;
It is concentric with the gate electrode of O and the gate electrode of N
The N2 layer is provided on the surface of the P2 layer on the outer periphery at a predetermined distance from the third layer, and is concentric with the gate 'f11 pole of the t main GTo and the gate electrode of the auxiliary GTQ, and the N2
A cathode electrode of the main GTO provided on the surface of the layer and supplied with an off-gate current from a control power supply, an anode connected to the gate ' of the upper GTO and a cathode connected to the gate electrode of the auxiliary GTO, and a t diode. In the GTo having an amplification gate structure, the auxiliary GT
A control circuit for a gate turn-off thyristor, characterized in that a switching control element whose control terminal is commonly connected to the gate electrode of the auxiliary GTO is inserted between the cathode electrode of the auxiliary GTO and the gate electrode of the upper GTO.