JPH022709A - Semiconductor switching device - Google Patents

Abstract

PURPOSE:To decrease an ON-state voltage, to widen a safe operating area, and to realize fast switching by providing the bypass of a gate current for turn-on between the base and the emitter of a transistor. CONSTITUTION:When the gate current for turn on is permitted to flow by using a gate circuit 3, the current flows in the gate terminal 8 of an arc- suppressing switching device 1, and flows out from the cathode terminal of the device 1, and returns to the circuit 3 bypassing a resistor 4 or a diode 5. Thereby, the device 1 is turned on, and it is possible to permit the current to flow on a load connected to a power source to be connected to an anode terminal 6 and the cathode terminal 7. Next, when the gate current for turning off the device 1 is permitted to flow from a terminal 8, a reverse bypass is formed between the gate and the cathode, and a depletion layer is formed, then, the device 1 is turned off. As a result, the transistor 2 is turned off, and no load current flows.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a self-extinguishing semiconductor switching device, and more particularly to a semiconductor switching device that can achieve low loss and high speed.

[Prior Art] As a prior art related to a semiconductor switching device, the technology described in, for example, Japanese Patent Application Laid-Open No. 52-60560 is known.

FIG. 2 is a diagram showing an example of a semiconductor switching device according to the prior art. In Fig. 2, 1 is a self-extinguishing switching element (hereinafter simply referred to as an element), 2 is a transistor, 6 is a 7 node terminal, 7 is a cathode terminal, 8 is a gate terminal, 9 is a base terminal, and 10 is a turn-on power supply. , 11
is a turn-off power supply, and 12.12' is a switch.

The conventional semiconductor switching device shown in FIG. 2 includes a turn-on power source 10 for turning on the element 1.
A turn-off power supply 11 connected between the gate and cathode of element 1 to turn off element 1 is connected between gate terminal 8 of element 1 and base terminal 9 of transistor 2, and a turn-off power supply 11 is connected between the gate terminal 8 of element 1 and the base terminal 9 of transistor 2. The anode of element 1 is connected to anode terminal 6, and the emitter of transistor 2 and the cathode of element 1 are connected to cathode terminal 7.

In the semiconductor switching device configured in this manner, when the switch 12 is closed, the gate terminal 8 of the element 1
A gate current is supplied from the turn-on power supply 10 to
Element 1 turns on.

As a result, the illustrated switching device is controlled to be on via element 1.

To turn off the illustrated switching device which is in the on state, switch 12' is closed. As a result, the gate current is extracted from the gate terminal 8 of the element 1, and the element 1 is shifted to the off state. At this time, the current pulled out by the gate current flows into the base of the transistor 2, so that the transistor 2 is turned on. As a result, the element 1 is rapidly shifted to the off state. When the element 1 is turned off, no base current is drawn from the gate terminal 8 of the element 1, so the transistor 2 is also turned off, and the entire switching device shown is turned off.

[Problems to be Solved by the Invention] In the prior art, the negative electrode side of the turn-on power source 10 and the positive electrode side of the turn-off power source 11 of the element 1 are connected.

Since they are connected through the base and emitter junctions of the transistor 2, there is a problem in that both types of sources must be provided independently in the device. Therefore, there is a problem in that it is not possible to use a commonly used turn-on/turn-off gate circuit in which the negative electrode side of the turn-on power source and the positive electrode side of the turn-off power source serve as a common electrode.

An object of the present invention is to solve the problems of the prior art, and to provide a semiconductor switching device in which a self-extinguishing switching element and a transistor are connected in parallel, in which the negative electrode side of a turn-on power source and the positive electrode side of a turn-off power source are common. It is an object of the present invention to provide a high-speed semiconductor switching device that has a low on-voltage, a wide safe operating range, and can use a turn-on/turn-off gate circuit serving as an electrode.

[Means for Solving the Problem] According to the present invention, the above object is achieved by connecting the negative electrode of the turn-on power source to the base terminal of the transistor in the prior art shown in FIG. and the positive electrode of the turn-off power source can be used as a common electrode, and between the base terminal of the transistor and the cathode terminal of the semiconductor switching device, that is,
This is achieved by providing a turn-on gate current bypass between the base and emitter of the transistor.

[Operation] When a bypass is provided between the base and emitter of a transistor, the gate current for turn-on flows into the gate terminal of the switching element, flows out from the cathode of the element, and returns via the bypass, turning the element on. can do. If there is no bypass, the device cannot be turned on because the turn-on gate current is blocked by the base-emitter junction of the transistor.

[Example] Hereinafter, an example of a semiconductor switching device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention. In Figure 1, 3 is a gate circuit for turn-on and turn-off, 4 is a resistor, 5 is a diode, and other symbols are second
This is the same as the case shown in the figure.

In FIG. 1, a self-extinguishing switching element 1 is an SI thyristor, a gate turn-off thyristor (GTO), etc. that has excellent turn-on and turn-off characteristics, and a transistor 2 is a bipolar transistor that has excellent turn-off characteristics. , SI transistor, etc., and may be a self-extinguishing switching element having transistor characteristics.

In the first embodiment of the present invention, the anode side of the element 1 and the transistor 2 are electrically connected in parallel to the anode terminal 6 and the cathode side to the cathode terminal 7 with low resistance, and the gate terminal of the element 1 is connected in parallel. A gate circuit 3 for turning on and off the element 1 is connected between the base terminal 9 of the transistor 2 and the base terminal 9 of the transistor 2, and a bypass resistor 4 or a diode 5 is connected between the base terminal 9 and the cathode terminal 7. It is configured by connecting. The gate circuit 3 has a turn-on power supply and a turn-off power supply therein,
The negative pole of the turn-on power supply and the positive pole of the turn-off power supply are commonly connected, and this common double positive is connected to the base terminal 9 of the transistor 2.

Next, the operation of the first embodiment of the present invention configured as described above will be explained.

When a turn-on gate current is applied using the gate circuit 3, this turn-on gate current flows into the gate terminal 8 of the element 1, flows out from the cathode side of the element 1, that is, the cathode terminal 7, and flows through the resistor 4 or diode. 5 and flows back to the gate circuit 3. This turns on element 1. As a result, the switching device of this embodiment applies a load to a load connected to a power supply (not shown) connected to an anode terminal 6 and a cathode terminal 7 through an element 1 that turns on quickly and has a low on-voltage. Can conduct current.

This interruption of the load current is characterized as follows.

Using the gate circuit 3, a gate current for turning off the element 1 flows out from the gate terminal 8 of the element 1. This current flows into the base of transistor 2 and flows out from its emitter, so that transistor 2 is turned on (low resistance). On the other hand, the turn-off gate current of the element 1 flowing out from the emitter flows into the cathode of the element 1, flows out through the gate terminal 8, and returns to the gate circuit 3. Therefore, since the gate and cathode of element 1 are reverse biased by gate circuit 3, a depletion layer is formed at the gate-cathode junction of element 1, resulting in turn-off (high resistance state). . The load current flowing through element 1 is commutated to transistor 2. When element 1 turns off,
The turn-off gate current of the element 1, that is, the base current of the transistor 2 no longer flows, the transistor 2 enters the off state, and no load current flows.

In the first embodiment of the present invention described above, the resistor 4 or diode 5 is used as a bypass, but if a large turn-on gate current is required, it is preferable to use the diode 5 as a bypass. In addition, in the above-described embodiment of the present invention, in order to realize a high-speed turn-off operation, it is possible to increase the on-voltage of transistor 2. In this case, in the on-state of the semiconductor switching device, only element 1 is working, so there are no particular problems.

In the first embodiment of the present invention, the element 1 and the transistor 2 can be formed in the same semiconductor substrate with a common cathode.

FIG. 3 is a block diagram showing a second embodiment of the present invention. In FIG. 3, 13 is an inverse base current source 13, and other symbols are the same as in FIG. 1.

The second embodiment of the present invention shown in FIG. 3 can speed up the attenuation of the load current at turn-off due to the action of the reverse base current source 13, and can significantly reduce the loss at turn-off. It is something.

Next, another embodiment of the present invention will be described in which the inverse base current source in this embodiment is concretely shown, and in which only one power supply is needed in the gate circuit.

FIG. 4 is a block diagram showing a third embodiment of the present invention. In FIG. 4, 14 is an SI thyristor, 15.15' is a DC power supply, and 16.16' is a MOSFET.

17 is a beam axle, and other symbols are the same as in FIG. 3.

In this embodiment, a static induction (SI) thyristor (withstand voltage 120 ov,
Effective current 30A, on voltage 1.2V, turn on time 1
μs) was used. In addition, as the transistor 2, pnp
This is a new type of transistor (N) that has a four-layer structure with a p base layer sheet resistance that is more than an order of magnitude smaller than that of conventional pnp transistors, and that greatly increases the voltage and current range in which it can operate safely. Withstand voltage 1200V, effective current 10A)
was used.

In FIG. 4, the gate circuit 3 for controlling turn-on and turn-off of the element 1 includes a normally-on thyristor 14.
, DC power supply 15, MOSFET 16 and reactor 17
The reverse base current source 13 connected between the base terminal 9 and the cathode terminal 7 of the transistor 2 is composed of a DC power supply 15' and a MOSFET 16'.

If no gate voltage is currently applied to the gate terminal G2 of the SI thyristor 14, this SI thyristor 14 is in the on state, and a reverse bias voltage (in this implementation) is applied between the gate and cathode of the element 1 by the power supply 15. In the example,
−15 V) is applied, and element 1 is in the off state.

In this state, MOSFET 16 is turned on and current is passed through the closed circuit of SI thyristor 14 → reactor 17 → MO8FET 16 → DC current g15, and SI thyristor 1
4 is turned off, the energy stored in the reactor 17 is discharged through the circuit consisting of the gate terminal 8 of the element 1 → the cathode of the element 1 → the resistor 4 (10Ω in this example), so that the 1 turns on.

When the SI thyristor 14 is turned on, the element 1 is turned off and the load current i can be cut off, as described above. In this case, the DC power supply 15' (-
5V) and a MOSFET 16 acts to speed up the turn-off of the transistor 2, thereby reducing the turn-off loss (collector current x voltage) of the transistor 2.

A third embodiment of the present invention shown in FIG.
L without connecting a snubber circuit between and cathode terminal 7.
An example of a turn-off waveform when used with a load is shown in FIG. In FIG.

The current 1111T)IYp lTR1 is the load current flowing through the element 1 and the transistor 2, respectively, as shown in FIG. Further, iB is the base current of the transistor 2.

The example in FIG. 5 shows the case where i, , = 150A,
It is shown that by flowing 'in=2OA, the attenuation of iT□ can be made very fast. In this example, the load current it is extremely large, 5 times the effective current of element 1 and 15 times the effective current of transistor 2, but the embodiment of the present invention shown in FIG. Even in this case, it can be safely turned off at the off-voltage v A=: goo v.

The same chip size (7.5 x 6.2 mm") as the device 1 of the embodiment of the present invention shown in FIG. 4, withstand voltage 1200 V, effective current 30 A, on-voltage 1.6 ■, turn-on time 3 μs
When a conventional switching device using GT○ is used with an L load and no snubber as described above, the off-voltage V
≦600V, iz≦30A. That is, the switching device according to the embodiment of the present invention has a lower on-voltage and a wider safe operating range than the conventional technology.
It is capable of high-speed switching.

[Effects of the Invention] As explained above, according to the present invention, a semiconductor switching device that has a low on-voltage, a wide safe operating range, and is capable of high-speed switching is obtained using a simple conventional gate circuit. be able to.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram showing a first embodiment of the present invention, Fig. 2 is a block diagram showing an example of the prior art, Fig. 3, 1...
Self-extinguishing switching element, 2...Transistor, 3...Gate circuit, 4...Resistor, 5...Diode, 6...・Anode terminal, 7...Cathode terminal, 8...Gate terminal, 9...Base terminal, 10...
・Turn-on power supply, 11...Turn-off power supply, 12.12'...Switch, 13...
...Reverse base current source, 14...SI thyristor, 15.15'...DC power supply, 16,16'
...MOSFET, 17...Reactor. Fig. 1 ・J5 people will disappear, book 2 6. Anode plume) Funeral image 14:51 Cyrisk 15.15' 1st generation Electrical East 16.16: MOS FES 17° Reactor

Claims (1)

[Claims] In a semiconductor switching device configured by connecting one or two self-extinguishing switching elements in parallel, a gate electrode of one self-extinguishing switching element that is turned on by a gate current, and transistor characteristics. A gate circuit for turning on and off the one self-extinguishing switching element is connected between the gate (base) electrode of the other self-extinguishing switching element having a gate (base)
A resistor or diode is connected in the opposite direction between the electrode and the source (emitter) electrode, and the anode side electrodes and cathode side electrodes of the two self-extinguishing switching elements are connected with low resistance. A semiconductor switching device characterized by: 2. The semiconductor switching device according to claim 1, wherein the other self-extinguishing switching element is a transistor having at least a PNPN four-layer structure. 3. The gate of the other self-extinguishing switching element (
3. The semiconductor switching device according to claim 1, further comprising a reverse base current source connected between the base (base) electrode and the source (emitter) electrode. 4. The semiconductor switching device according to claim 1, 2 or 3, wherein the two self-extinguishing switching elements are formed within the same semiconductor substrate.