JPH0254971B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semiconductor switch circuit without a self-holding function that turns the switch on and off depending on the presence or absence of a gate current.

(Prior art) As a semiconductor switch that can control large current switching with a small gate current and has a small on-voltage,
PNPN type switches are well known. this
Among PNPN type switches, those that can turn off direct current by applying control from the gate are called GTO (Gate Turn Off) type PNPN switches.

FIG. 1 shows an equivalent circuit diagram of a conventional GTO type PNPN switch. In the figure,
1, 2, 3 and 4 are an anode terminal, a cathode terminal, an on control gate terminal and an off control gate terminal, respectively, 5 is a PNP transistor, and 6 and 7 are NPN transistors. transistor 5
and 6 equivalently constitute a PNPN type switch.
Transistor 7 is for cutting off the DC anode current, and by turning on transistor 7 when the switch is turned on, it shorts the base and emitter of transistor 6, turns off transistor 6, and disconnects transistors 5 and 6. Turn off the PNPN type switch.

The operation when performing a switching operation with such a configuration will be explained with reference to FIG.

(i) First, when the switch is in the OFF state, the inflow of the gate current for ON drive (hereinafter abbreviated as I _G-ON ) from the outside of the figure through the ON control gate terminal 3 is stopped. transistor 5
and 6 are in the off state. On the other hand, a gate current for off drive (hereinafter abbreviated as I _G-OFF ) from outside the figure flows in through the off control gate terminal 4.
The base-emitter junction of transistor 7 is in the on state.

(ii) Next, to turn the switch from off to on, stop the gate current I _G-OFF and
I _G-ON is introduced from outside the diagram through terminal 3. As a result, transistor 7 is turned off, transistors 5 and 6 are turned on, and an anode current flows from the outside of the figure through terminal 1, becomes a cathode current through terminal 2, and flows out of the figure.

(iii) Furthermore, to turn the switch from on to off, stop the gate current I _G-ON and turn the gate current
I _G-OFF is introduced from outside the figure through terminal 4. As a result, transistor 7 is turned on, the base and emitter of transistor 6 are short-circuited, transistor 6 is turned off, and the collector current of transistor 6 is stopped. Therefore, the base current of transistor 5 also stops, transistor 5 is also turned off, and the transistor 5 and 6
The PNPN type switch is in the off state.

Due to the above operation, even when the switch is turned off, the gate current for off-drive continues to flow into the main current path from terminal 4 to the base of transistor 7 to the emitter to terminal 2. Therefore, strict The conventional GTO type PNPN switch shown in FIG. 1 cannot be applied to a circuit network that requires an OFF state. Further, in order to control the on/off of the switch, it is necessary to alternately supply gate currents for on-drive and off-drive, making switching control complicated.

(Object of the Invention) In order to eliminate the above-mentioned drawbacks, the present invention enables on/off control of a switch depending on the presence or absence of a gate current for on-drive. It is an object of the present invention to provide a semiconductor switch circuit that prevents off-control gate current from leaking into a current path.

(Structure of the Invention) In order to achieve the above object, the present invention provides first and second transistors having two collectors, and third, fourth, and fifth transistors of complementary conductivity type.
and a sixth transistor, the first collector of the first transistor and the base of the third transistor are connected, and the base of the first transistor and the collector of the third transistor are connected. to equivalently constitute a PNPN type switch, connect the collector of the fourth transistor and the first collector of the second transistor to the base of the third transistor, and connect the base of the fourth transistor to the collector of the fourth transistor and the first collector of the second transistor. The collector of the fifth transistor and the second collector of the first transistor are connected, the base of the fifth transistor is connected to the second collector of the second transistor, and the second collector of the second transistor is connected to the base of the fifth transistor. The base and the collector of the sixth transistor are connected, the emitters of the third, fourth, fifth and sixth transistors are connected to form a cathode terminal, and the emitters of the first and second transistors are connected. The gist of the invention is a semiconductor switch circuit characterized in that the base of the sixth transistor is used as an anode terminal, and the base of the sixth transistor is used as a gate terminal.

Furthermore, the present invention provides a first collector having two collectors;
a second transistor and third, fourth, fifth and sixth transistors of complementary conductivity types; the first collector of the first transistor and the base of the third transistor; , the base of the first transistor and the collector of the third transistor are connected to equivalently constitute a PNPN type switch, and the base of the third transistor is connected to the collector of the fourth transistor. The first collector of the second transistor is connected to the base of the fourth transistor, and the collector of the fifth transistor and the first collector are connected to the base of the fourth transistor.
A second collector of the second transistor is connected to the base of the fifth transistor, and a base of the second transistor and a collector of the sixth transistor are connected to each other. the emitters of the first and second transistors are connected to form an anode terminal, the emitters of the fifth and sixth transistors are connected to form a cathode terminal, and the emitters of the third transistor are connected to form at least one cathode terminal. connecting the emitter of the fourth transistor to the cathode terminal directly or through a smaller number of diodes than the diodes in the forward direction;
The gist of the invention is a semiconductor switch circuit characterized in that the base of the sixth transistor is used as a gate terminal.

Next, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the embodiments are merely illustrative, and it goes without saying that various changes and improvements can be made without departing from the spirit of the present invention.

FIG. 2 shows the first part of the semiconductor switch circuit of the present invention.
In the figure, 1 and 2 are an anode terminal and a cathode terminal, respectively, and 12 is a gate terminal. Further, 8 and 9 are first and second PNP type transistors having two collector terminals 81, 82 and 91, 92, respectively, and 6 is a third NPN type transistor, and transistors 6 and 8 are equivalent. A PNPN type switch is constructed. 7 is a fourth NPN type transistor for shorting between the emitter and base of transistor 6; 10 is for shorting between the emitter and base of transistor 7;
The fifth NPN type transistor 11 is a sixth NPN type transistor for turning on the transistor 9.

The operating principle will be explained using the circuit shown in FIG.

(i) First, when the switch is in the off state, the supply of gate current (hereinafter abbreviated as I _G ) from the outside in the figure via the gate terminal 12 is stopped, and the transistors 6, 7, 8, 9, 10 and 11 are all in the off state.

(ii) To turn the switch from off to on, a gate current I _G is supplied from outside the figure via the gate terminal 12. Then, transistor 11 turns on due to the supply of gate current I _G , and transistor 1
As the collector current is 1, the transistor 9 whose base current is drawn also turns on. Therefore, transistor 11 is supplied with a base current by the current in collector 92 of transistor 9 and turns on, and transistor 7 continues to be off because its emitter and base are short-circuited. At the same time, the transistor 6 and the transistor 9
The base current is supplied by the current in the collector 91 of and turns on, and as a result, the transistor 8 turns on. That is, the PNPN type switch consisting of transistors 6 and 8 is turned on, and an anode current flows from outside the figure through the anode terminal 1, and flows out as a cathode current through the cathode terminal 2.

(iii) When the switch is in the on state, transistors 6, 8, 9, 10 and 11 are on, and transistor 7 is on. That is,
Most of the base current of the transistor 6 is supplied as a current to the collector 81 of the transistor 8, and a part is supplied as a current to the collector 91 of the transistor 9. Further, the collector current of the transistor 6 is supplied as the base current of the transistor 8. The collector current of the transistor 10 is supplied as the current of the collector 82 of the transistor 8, and the base current of the transistor 10 is supplied as the current of the collector 92 of the transistor 9. The collector current of the transistor 11 is supplied as the base current of the transistor 9, and the base current of the transistor 11 is supplied as the gate current from outside the figure through the gate terminal 12. Transistor 7 is transistor 1
0 short-circuits the emitter and base, so it is off.

(iv) To turn the switch from on to off, first stop supplying the gate current _IG . Then, transistor 11 turns from on to off, so that the base voltage of transistor 9 stops and transistor 9 also turns off. As a result, the current in the collector 92 of the transistor 9, which had been supplied as the base current, stops, so the transistor 10 turns from on to off, and the current in the collector 82 of the transistor 8 switches to the base current of the transistor 7, causing the transistor 10 to turn off. 7 turns from off to on. Then, the emitter and base of transistor 6 are short-circuited, transistor 6 is turned from on to off, and the base current of transistor 8 is therefore stopped and transistor 8 is also turned from on to off. The switch is turned off. Since the transistor 8 is turned off after this,
Since the current in the collector 82 of the transistor 8 is stopped, the supply of the base current to the transistor 7 is stopped, and the transistor 7 also turns from on to off.

(v) When the switch turns off and becomes stable, transistors 6, 7, 8, 9, 1
0 and 11 are all off.

As described above, in the present invention, since the on/off of the switch is controlled depending on the presence/absence of the gate current, the switching control is simple. Furthermore, there is no need to supply a gate current for off-driving the switch during its off period, and no gate current leaks outside the figure through the cathode terminal 2.
Furthermore, the gate current supplied to turn on the switch is supplied as the base current of transistor 11 in order to keep transistor 11 in the figure on, and is a very small current, making it difficult to operate a highly sensitive switch. The advantage of configurability can be achieved in exactly the same way as in the prior art.

Note that since the switch circuit shown in FIG. 2 is used by being incorporated into a part of various circuits, the levels of the anode terminal 1 and cathode terminal 2 cannot be specified. For example, when the anode terminal 1 is connected to the positive power supply, When used for the purpose of switching the current to a load connected between the cathode terminal 2 and a low potential point, the transistor 11
There may be cases where it is not possible to flow the base current (gate current I _G-ON ) from the gate terminal 12 to turn on the transistor 9 sufficiently, but in that case, take out the base of the transistor 9 as another gate terminal 12' and The same operation as described above can be performed by applying a low voltage to the gate terminal 12' to draw out the current. In this case, it goes without saying that the transistor 11 becomes unnecessary, but by providing both the gate terminals 12 and 12', the versatility of the switch circuit is increased.

FIG. 3 shows another embodiment of the present invention,
One feature is that a diode 13 is inserted between the emitter of the transistor 6 and the cathode terminal 2. In addition, the other configurations are the same as in Fig. 2,
Identical parts are denoted by the same reference numerals, and their explanations will be omitted. Therefore, in this embodiment, the off-control operation of the transistor 6 by the transistor 7 is further ensured, and the forward drop voltage of the diode 13 is added to the saturation voltage between the collector and emitter when the transistor 7 is on. You will be given some leeway. In other words, in order to turn off the transistor 6, it is necessary to maintain the voltage between its base and emitter at a value smaller than the rising voltage.
If the diode 13 is not provided, it is necessary to make the saturation voltage between the collector and emitter of the transistor 7 smaller than the above-mentioned rising voltage. In other words, the transistor 6 can be turned off even when it is not completely saturated. Note that the number of diodes 13 is not limited to one, and the effect can be further enhanced by connecting a plurality of diodes in series in the forward direction.

FIG. 4 shows yet another embodiment,
This makes the off control operation of not only transistor 6 but also transistor 7 more reliable. The configuration is that diodes 13 and 14 are inserted between the emitter of the transistor 6 and the cathode terminal 2, and a diode 15 is inserted between the emitter of the transistor 7 and the cathode terminal 2.
It is the same as that shown in FIG. 3 and FIG. 3, and there is no change in the operation as a switch circuit. Furthermore, although the number of diodes is not limited to that shown in the figure, the transistor 7
Since the diode 15 connected to the emitter path of transistor 6 has a reverse effect on the off-state of transistor 6, the number of diodes inserted in the emitter path of transistor 6 is equal to the number of diodes inserted in the emitter path of transistor 7. There must always be more than .

(Effects of the Invention) As explained above, the semiconductor switch circuit according to the present invention enables on/off control of the switch by the presence/absence of a minute gate current, and the main current during the off period of the switch. Since the gate current for off-driving does not flow into the path, it can be applied to circuit networks that require strict off-switching operation of DC current. It has the advantage of being able to replace semiconductor switch circuits.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a conventional semiconductor switch circuit.
FIG. 2 shows a first embodiment of the semiconductor switch circuit of the invention, FIG. 3 shows a second embodiment of the invention, and FIG. 4 shows a third embodiment of the invention. 1... Anode terminal, 2... Cathode terminal, 3
...On control gate terminal, 4...Off control gate terminal, 5...PNP type transistor, 6, 7...
... NPN type transistor, 8, 9... PNP type transistor, 10, 11... NPN type transistor, 12... Gate terminal, 12'... Gate terminal, 13, 14, 15... Diode, 81,
82, 91, 92...PNP type transistor collector.

Claims (1)

[Scope of Claims] 1. First and second transistors each having two collectors, and third, fourth, fifth, and sixth transistors having conductivity types complementary to the transistors, The first collector of the transistor and the base of the third transistor are connected, and the base of the first transistor and the collector of the third transistor are connected to equivalently
A PNPN type switch is configured, wherein the base of the third transistor is connected to the collector of the fourth transistor and the first collector of the second transistor, and the base of the fourth transistor is connected to the fifth transistor. and the second collector of the first transistor are connected, and the collector of the fifth transistor is connected to the second collector of the first transistor.
a second collector of the second transistor is connected to the base of the transistor; a base of the second transistor is connected to a collector of the sixth transistor; The emitters of the sixth transistor are connected to form a cathode terminal, the emitters of the first and second transistors are connected to form an anode terminal, and the sixth transistor is connected to form an anode terminal.
A semiconductor switch circuit characterized in that the base of the transistor is used as a gate terminal. 2. The semiconductor switch circuit according to claim 1, wherein the base of the second transistor is used as another gate terminal, and the semiconductor switch circuit is driven by drawing a current from the other gate terminal. 3. First and second transistors having two collectors, and third, fourth, fifth, and sixth transistors of conductivity types complementary to the transistors, and the first transistor of the first transistor Equivalently, the collector and the base of the third transistor are connected, and the base of the first transistor and the collector of the third transistor are connected.
A PNPN type switch is configured, the collector of the fourth transistor and the first collector of the second transistor are connected to the base of the third transistor, and the fifth transistor is connected to the base of the fourth transistor. and the second collector of the first transistor are connected, and the collector of the fifth transistor is connected to the second collector of the first transistor.
A second collector of the second transistor is connected to the base of the transistor, a base of the second transistor is connected to the collector of the sixth transistor, and the emitters of the first and second transistors are connected to each other. The emitters of the fifth and sixth transistors are connected to form an anode terminal, and the emitters of the third transistor are connected to the cathode terminal through at least one diode in the forward direction. and the emitter of the fourth transistor is connected to the cathode terminal directly or through a smaller number of diodes than the diode in the forward direction, and the base of the sixth transistor is the gate terminal. A semiconductor switch circuit. 4. The semiconductor switch circuit according to claim 3, wherein the base of the second transistor is used as another gate terminal, and the semiconductor switch circuit is driven by drawing a current from the other gate terminal.