JPS634665A - Composite transistor - Google Patents

Abstract

PURPOSE:To increase working speed by including a circuit element automatically inverting the phase of signal voltage applied to a gate for one MOSFET and the phase of signal voltage applied to the other MOSFET without phase shift. CONSTITUTION:A gate terminal G3 for an MOSFET 4 is connected to a gate G1 for an MOSFET 2. A drain in the MOSFET 4 is connected to a DC power supply through a resistor 5 while being connected to a gate G2 for an MOSFET 3. A source in the MOSFET 4 is grounded or connected to an emitter in a bipolar transistor 1. When a control signal is transmitted over the gate G3 for the MOSFET 4, the phase of the gate G1 connected to the gate G3 and the gate G2 can be inverted, thus easily turn-ON or turn-OFF controlling an MOS bipolar composite type transistor positively.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a composite transistor, such as a MOSFET.
Involved in switching semiconductor devices such as T. %.

O related to an MQS composite transistor in which a M08FBT is connected in parallel between the base, emitter, and collector of a bipolar transistor. [Prior art] When a semiconductor device such as a transistor is used in a power switching circuit, the breakdown voltage , on-resistance, and switching speed are important performance factors.

It is extremely difficult to satisfy these performances with a single MOSFET or bipolar transistor, so
In recent years, M which combines MOSFET and bipolar elements
Development of an OS bipolar composite device is underway (Japanese Patent Application Laid-open No. 196560/1983).

FIG. 3 shows an equivalent circuit of a conventional composite type element.

1 is a bipolar transistor with a collector C and an emitter E, and 2 is a MOS transistor. When a positive voltage signal is applied to the gate G of MOS transistor 2, MOS transistor 2 becomes conductive.

The MOS 1'' transistor 2 becomes conductive, and a base current is supplied to the bipolar transistor 1 through the MOS transistor 2. That is, minority carriers are injected into the base of the bipolar transistor 1.

This causes the bipolar transistor l to conduct.

On the other hand, when the bibolar transistor l turns off, the turn-off time tends to be delayed due to the accumulation effect of the minority carriers injected into the base. To shorten this, the accumulation effect mentioned above must be reduced.

Figure 4 shows an equivalent circuit of a conventional MOSFET composite switching conductor device with an added circuit for extracting accumulated carriers in the base (Extended A of the 17th Solid State Elements and Materials Conference).
bstructs of the 17th
eonfer-ence on 5olid
8tate Devices and Mata
rI-als, TOk7(le 1985 No. 389
~392 pages).

In the circuit shown in Fig. 4, when turning on the bipolar transistor 1, a positive voltage is applied to the gate of MOS transistor 2, Gll, to make it conductive, and at the same time, the gate G of MOS transistor 1 becomes the same potential as the emitter. It is controlled to maintain it in a non-conducting state.

On the other hand, during turn-off and steady-state off.

The gate G1 of MO3FET2 is placed at the same level as the emitter to make it non-conductive, and at the same time, a positive voltage is applied to the gate G2 of MOSFET3 to 1M08FI! Make tT3 conductive.

As a result, accumulated carriers in the base of the bipolar transistor 1 are led out to the emitter E through the MO13FBT 3 , and the bipolar transistor 1 is turned off.

As is clear from the above, the turn-on of the device shown in FIG.
When performing turn-off, two MOSFETs 2.
It is necessary to apply control voltages with opposite phases to the gates G, , G, of the three gates.

[Problem that the invention seeks to solve]

Therefore, in the past, a 2(@) signal generator was used to generate two control signals with different phases and 1
There is a problem in that a phase shift is likely to occur between the two control signals. Obviously, if the two control signals are out of phase, the turn-on and turn-off responses will be delayed.
This results in the drawback that speeding up the operation is hindered.

An object of the present invention is to provide a circuit element that automatically reverses the phase of a signal voltage applied to the gate of one MOSFET of an MO3 bipolar composite transistor and the phase of a signal voltage applied to the gate of the other MOSFET, without any phase shift. To provide a composite transistor including the present invention.

[Means for solving problems]

In order to solve the above problems, in the present invention, the fourth
As in the conventional example shown in the figure, in a composite transistor in which first and second MOSFETs are connected in parallel between the base and collector of a bipolar transistor and between the base and emitter, respectively, there is a connection between the gate of the second MOSFET and the emitter of the bipolar transistor. 3rd M08 FET
are connected in parallel, and the gate of the third M03FET is connected to the first M03FET.
Commonly connected to the gate of OSFE'l', and connected to a resistor or a fourth M08 which is complementary to the third M08 FET.
A configuration was adopted in which the gate of the second M08F'ET was connected to a DC power supply via an FET.

[Effect]

3rd MOSFgT gyopi 1st MOSFFi'l'
is in the on state, the gate potential of the second M08FET is at a low level, so the second M08FET is in the off state and the bipolar transistor is in the on state. On the other hand, the third M08FET and the first M08FET are in the on state.

When in the off state, the gate potential of the 12M08FET is at a high level, so the second M08FET is in the on state and the bipolar transistor is in the off state.

In other words, the phases of the signal voltages applied to the gates of the first and second M08FETs are automatically and always kept in opposite phases without causing a phase shift, resulting in a delay in operation during turn-on and turn-off. In addition, the 4th M08FE, which is complementary to the 3rd M08FET,
DC'1 is applied to the gate of the second M08FBT via T.
If the configuration is such that the gate of the second M08FBT is selectively connected to either the DC power source or the emitter of the bipolar transistor, the control circuit section does not include a resistance component. It is possible to extremely reduce power loss in this section.

〔Example〕

FIG. 1 shows a circuit configuration of an embodiment of the present invention, which includes a composite transistor having two MOSFETs and a circuit element that mutually inverts the phases of voltage signals applied to the gates of the respective MOSFETs. -4 and 5 are MOSb'E that constitutes a circuit that inverts the phase of the pressure-sensitive signal applied to the gate G2 of the 1MOS bipolar composite transistor.
T and resistor are shown.

As shown in the figure, the gate terminal G of MOSFET 4.

is connected to the gate GI of MOSFIET2.

The drain of MOSFET4 is connected to the DC power supply via resistor 5, and the gate G of MOSFET3 is connected to the DC power supply via resistor 5.
Connected to 2.

The source of MO3FET 4 is grounded or
Connected to the emitter of bipolar transistor l.

In such a configuration, if a DC voltage (approximately 5V) is applied to the drain of %MOSFET4 through the resistor 58 and a control voltage of 10 to 15V is applied to the gate G8, MOi9
FET 4 becomes conductive.

As a result, the voltage of the gate G2 becomes lower than the gate threshold voltage, and the MOSFET 3 is turned off. At the same time, %MOSF'ET2 becomes conductive and current is supplied to the base of bipolar transistor 1.

Bipolar transistor 1 becomes conductive.

- When the bipolar transistor l is placed in a blocking state, the voltage of the control signal applied to the gate G3 is set as follows.

Make it below the gate threshold voltage. MOofJFgT 4
is turned off, and a DC voltage is applied to the gate G through the resistor 5, so that the MOSFET 3 becomes conductive. At the same time, MOSF'ET 2 turns off, so
Bipolar transistor l is quickly turned off.

In this way, the control signal is applied to the gate G3 of MOSFET4.
By adding this, the phases of gate G1 and gate G connected to this can be reversed.

MOS bipolar composite transistors can be easily and reliably controlled to turn on or turn off.

In the configuration of the present invention comprising a MOS bipolar composite transistor and the phase inverting circuit element &MO3F
Hitachi mMO13FmiiT28 as ET4
Using K296, the resistance value of resistor 5 is 5oΩ.

The power supply voltage is 5V, a phase inversion circuit is used, and the collector
As a result of controlling a MOS bipolar composite transistor with a base-to-base withstand voltage S O V and a current capacity of 5 people,
The collector-emitter voltage of the MOS bipolar composite transistor when off was equal to the collector-base breakdown voltage, and the on-current density was 30 people/d.

In addition, the turn-off time is 0.5 μs in a resistive load.
In the case of a conductive load, the time was 0.8 μs. ◎Figure 2 shows the first
The MOSFET for phase inversion shown in the figure is integrated on the same silicon chip as the MOS bipolar composite transistor.

1 shows a cross-sectional structure of a switching semiconductor device according to the present invention.

An n- layer 12 is grown on one main surface of the +n substrate 11, and within this n-I@12, a p region! 3,14°15 are formed by selective diffusion. moreover.

As shown in each of the above p regions 13 to 15,
n regions 21 to 26 are formed by selective diffusion. Then, emitter electrodes 31. Collector [pole 32° and other electrodes are formed, as well as gate line image films (not shown) and gate electrodes of PET 2-4, by known and suitable means.

It will be readily understood by those skilled in the art that the device of FIG. 2 has the circuit configuration of FIG. 1 and operates as described above.

In the structure shown in FIG. 2, the circuit portion (MOSPET 4 portion) for inverting the phase of the signal voltage is separated from the MOS bipolar transistor 5 portion 1.2.3 by a pa junction and formed within the same chip.

As described above, the circuit element of the present invention can easily realize a composite structure, and can reliably perform gate control of transistors in a MOS bipolar composite structure.

In the embodiment of FIG. 1, MOSF'h:T 4 and resistor 5 are used to invert the phase of the gate control signal of MOSFET 3.

For this purpose, in the ON state of MOSFET4.

There is no loss due to the single current flowing through resistor 5, and when MOSFET 4 switches from on to off, 1
There is a tendency for power loss to become large, such as a loss caused by a current that passes through the effective capacitance of MOSFgT3.

To avoid this, use resistor 5 in Figure 1.

MO! It is preferable to replace 9FET 4 with a complementary MOSFET and connect its gate in common with the gate G of MOSFET 4.

As is clear, in this case, since there is no resistance component, no power loss occurs. Furthermore, the above substitution has the advantage that all necessary circuit elements can be integrated.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a MOS bipolar composite transistor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an example in which the embodiment of the present invention is integrated on one silicon chip, and FIG. Equivalent circuit diagram of a conventional MOS bipolar composite transistor Figure 4 is an equivalent circuit diagram of a conventional MOS bipolar composite transistor with improved turn-off characteristics. l...Bipolar transistor, 2.3.4...M
OS transistor, 5... Resistor agent Patent attorney Michi Hiraki Figure 1 H Figure 2

Claims (4)

[Claims] (1) a bipolar transistor and a first MOS transistor connected in parallel between its base and collector;
and a second MOS transistor connected in parallel between the base and emitter of the bipolar transistor, wherein a source-drain circuit of a third MOS transistor is provided between the gate of the second MOS transistor and the emitter of the bipolar transistor. A composite transistor characterized in that the transistors are connected in parallel, the gate of the third MOS transistor is connected to the gate of the first MOS transistor, and the gate of the second MOS transistor is connected to a DC power supply via a circuit element. (2) The composite transistor according to claim 1, wherein the circuit element is a resistor. (3) The circuit element is a fourth MOS transistor complementary to the third MOS transistor, and the third and fourth MOS transistors are complementary to the third MOS transistor.
2. The composite transistor according to claim 1, wherein the gates of the OS transistors are connected in common. (4) Bipolar transistor and first to third MOS
Claim 2 or 3, characterized in that the transistors are integrated into the same semiconductor chip.
Composite transistor described in section.