JP2001251846A - Power semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power semiconductor device where a normal SIT is a main device and which can relax the hardness of the handing of a conventional SIT and can be driven easily, and moreover can made the most of the performance of SIT. SOLUTION: This power semiconductor device, composed mainly of an SIT1, MOSFET2, Zener diode 3, diode 5, and DC power source 4, and the source for the SIT1 and the drain of the MOSFET2 are connected with each other in series. The gate of the above SIT1 is connected to the cathode of the Zener diode 3, and the anode of the Zener diode 3 is connected to the source of the MOSFET2. The above DC power source 4 is connected via the diode 5 to both ends of the above Zener diode 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power semiconductor device suitable for use mainly in a power supply portion of industrial equipment, and more particularly to a power semiconductor device using an electrostatic induction transistor as a power control element. Related to the device.

[0002]

2. Description of the Related Art An electrostatic induction transistor (hereinafter referred to as SIT)
Is a power semiconductor capable of high-speed operation in a high-voltage and high-power range, and is widely used in industrial heating devices, high-frequency oscillators, medium-wave broadcasters, and the like.

In general, the SIT has a normally-on characteristic in which a drain current flows when a bias voltage is 0 V. When a drain voltage is applied in a state where a negative bias is not sufficiently applied to a gate, an element is damaged by a large drain current. There is a problem that handling is more difficult than a transistor having normally-off characteristics such as a bipolar transistor, an insulated gate field effect transistor (hereinafter, referred to as MOSFET), and an insulated gate bipolar transistor (hereinafter, referred to as IGBT). It is pointed out.

[0004] In addition, a general 300 to 3000 W class S
To turn off IT, a negative bias of several tens of volts is required. Further, in order to turn on the SIT with low loss, it is necessary to flow a forward current of several hundred mA to the gate, so that the driving circuit becomes more complicated than a MOS gate type power semiconductor such as MOSFET or IGBT. The problem has been pointed out.

FIG. 5 is a circuit diagram showing the SIT and its driving circuit. As shown in FIG. 5, the drive circuit 9 requires both a positive voltage and a negative voltage as a power supply.

On the other hand, in an electrostatic induction thyristor (hereinafter, SI thyristor) having normally-on characteristics like SIT, an SI thyristor 11 and a MOSF as shown in FIG.
A normally-off type composite semiconductor 10 using a cascode connection of the ET 12 has been reported. This composite semiconductor is
Thyristor 11 is the main device and MOSFET 12
Are configured to control the SI thyristor 11.

Further, the gate of the SI thyristor 11 and the MO
Utilizing the junction capacitance of the Zener diode 13 connected between the sources of the SFETs 12, it plays a role of assisting the ON operation by flowing a forward gate current.

[0008]

However, this configuration is called S
Even when applied to IT, it is difficult to keep the forward current flowing throughout the ON period, and the performance of SIT cannot be fully utilized.

Therefore, an object of the present invention is to provide a power semiconductor device using a normally-on type SIT as a main device,
An object of the present invention is to provide a power semiconductor device capable of alleviating the difficulty of handling a conventional SIT, facilitating driving, and fully utilizing the performance of the SIT.

[0010]

According to the power semiconductor device of the present invention, the source of the static induction type transistor and the drain of the insulated gate field effect transistor are connected in series, and the gate of the static induction type transistor is connected. The power semiconductor device has a Zener diode connected to a cathode, an anode of the Zener diode connected to a source of an insulated gate field effect transistor, and a DC power supply connected to both ends of the Zener diode.

According to the present invention, in the power semiconductor device, the positive electrode of the DC power supply is connected to the cathode of the Zener diode via a diode, and the negative electrode of the DC power supply is connected to the anode of the Zener diode. Is obtained.

Further, according to the present invention, in the power semiconductor device, the power semiconductor device may be obtained by externally connecting individual components, or may be obtained by internally connecting the individual components inside the same unit. Alternatively, a power semiconductor device which is obtained by being formed on the same semiconductor substrate is obtained.

That is, the present invention relates to a power semiconductor device mainly including an electrostatic induction transistor, an insulated gate field effect transistor, a Zener diode, a diode, and a DC power supply. The source of the transistor is connected in series with the drain of the insulated gate field effect transistor, the gate of the electrostatic induction transistor is connected to the cathode of the Zener diode, and the anode of the Zener diode is connected to the insulated gate type. Connect to the source of the field effect transistor,
A power semiconductor device in which the DC power supply is connected to both ends of the Zener diode via a diode.

Further, according to the present invention, in the power semiconductor device, a positive electrode of the DC power supply is connected to a cathode of the Zener diode via a diode, and a negative electrode of the DC power supply is connected to an anode of the Zener diode. Power semiconductor device.

Further, the present invention provides the power semiconductor device, wherein the electrostatic induction type transistor, the insulated gate type field effect transistor, a Zener diode, a diode, and a DC power supply are externally connected. Power semiconductor device.

Further, the present invention provides the power semiconductor device, wherein the electrostatic induction transistor, the insulated gate field effect transistor, the Zener diode, the diode, and the DC power supply are arranged in the same unit. A power semiconductor device having a configuration in which the components are connected.

Further, according to the present invention, in the power semiconductor device, the electrostatic induction transistor, the insulated gate field effect transistor, the Zener diode, the diode, and the DC power supply are formed on the same semiconductor substrate. This is a power semiconductor device having a configuration as described above.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power semiconductor device according to an embodiment of the present invention will be described below.

(Embodiment 1) FIG. 1 shows a circuit configuration diagram of a power semiconductor device according to Embodiment 1 of the present invention. The circuit configuration of FIG. 1 utilizes cascode connection between SIT1 and MOSFET2. First, sources S1 and M of SIT1
The drain D2 of OSFET2 is connected in series, and SIT1
Is connected to the cathode K3 of the Zener diode 3, and the anode A3 of the Zener diode 3 is connected to the MOS.
Connected to the source S2 of the FET2, the Zener diode 3
DC power supply 4 is connected to both ends. At this time, the DC power supply 4
The positive electrode 4a is connected to the cathode K3 of the Zener diode, and the negative electrode 4b of the DC power supply 4 is connected to the anode A3 of the Zener diode 3.

Further, if necessary, a diode 5 is connected to the positive electrode 4a of the DC power supply 4 in a forward direction for protection of the power supply (that is, the anode A is provided on the DC power supply side and the cathode K5 is provided on the zener diode side). And so on) in series.

The operation of the power semiconductor device will be described below.

First, when the control electrode is at 0 V, the MOSFE
T2 is in an off state, and the voltage of the power supply 7 applied to the drain D1 of SIT1 causes a potential difference between the drain D2 and the source S2 of the MOSFET2 to make the drain D2 positive. When this potential difference becomes equal to or higher than the Zener voltage, a voltage that causes the gate G1 to be negative is applied between the gate G1 and the source S1 of the SIT1. When the voltage amplification factor of SIT1 is sufficiently large, SIT1 is turned off, and most of the power supply voltage applied between the main electrode (the drain D1 of SIT1 and the source S2 of MOSFET2) is S
The remaining voltage is divided between the drain D1 and the source S1 of the IT1 and between the drain D2 and the source S2 of the MOSFET2.

Next, when a voltage higher than the cut-off voltage Vth of the MOSFET 2 is applied to the control electrode, the MOSFET 2 is turned on, and the voltage between the drain D2 and the source S2 of the MOSFET 2 decreases. Therefore, the gate G1 of SIT1
-The voltage between the sources S1 also decreases. Where MOSFET
When the voltage between the drain D2 and the source S2 of the SIT2 becomes equal to or less than the Zener voltage, a forward gate current flows from the DC power supply 4 between the gate G1 and the source S1 of the SIT1, and the SIT1
1 is turned on.

Further, when the control electrode becomes 0V, the semiconductor device 6a is turned off again. At this time, the current drawn from the gate G1 of SIT1 flows through the Zener diode 3 to the source S2 of MOSFET2.

That is, the power semiconductor device according to the present invention comprises:
SIT1 is used as a main device, and MOSFET2 is used as a control device for SIT1. As described above, if the voltage amplification factor of SIT1 is sufficiently large, the main electrodes D1.S
Most of the voltage applied between the two is applied to SIT1,
Only the sum of the voltage required to turn off SIT1 and the Zener voltage of Zener diode 3 is applied to MOSFET2.

Accordingly, the breakdown voltage of the MOSFET 2 may be low and the on-resistance can be suppressed low, so that the SIT 1 can be controlled without affecting the characteristics of the main device SIT 1.

The DC power supply 4 is used to supply a stable forward current to the gate G1 when turning on the SIT1, and its voltage needs to be adjusted in advance to obtain a desired current. In this embodiment, the voltage is set to 5V. The Zener voltage of the Zener diode 3 needs to be set higher than the voltage of the DC power supply 4.
Must be in the range of the voltage minus the voltage required to turn off. In this embodiment, the Zener diode 3
Was set to 5.5V.

The role of the Zener diode 3 is as follows.
The gate extraction current when SIT1 is turned off is
The current flows through the source S2 of the ET2, so long as the current capacity can withstand the extraction current, and a large junction capacity is not required. As an example, the voltage VGS between the gate G1 and the source S1 of the SIT1 when a 6V rectangular wave (frequency 10 kHz, duty 50%) is input as a control input
(SIT) and the gate current waveform IG (SIT) are shown in FIG.
Shown in FIG. 4 shows the output current ID (SIT + FET) and the voltage waveform VDS (SIT + FET), that is, the voltage current waveform of the main electrode.

Here, as is apparent from the waveform, the power semiconductor device according to the present invention exhibits normally-off characteristics as a whole. Further, the drive current of SIT1 at the time of ON continues to flow throughout the ON period, and as a result, the performance of SIT1 can be sufficiently brought out.

Further, when the power supply is turned off, a negative bias is supplied to the gate G1 of the SIT1 by using the voltage of the power supply 7 for the main electrode. Therefore, it is not necessary to prepare a power supply for the negative bias unlike the prior art, and the handling is easy. It is. In addition, since this semiconductor device operates as a voltage control type device, the configuration of a driver circuit can be simplified as compared with the related art.

The circuit configuration of the first embodiment is the same as that of SIT1
In addition, MOSFET2 is a main component,
Even if the MOSFET 2 is replaced with an IGBT,
A similar effect can be obtained.

(Embodiment 2) FIG. 2 shows a circuit configuration diagram of a power semiconductor device according to Embodiment 2 of the present invention. In the present embodiment, the voltage of the main electrode power source 7 is used as a DC power source instead of the DC power source 4 of the first embodiment, and a gate forward current flows through the SIT. Good normally-on characteristics are obtained.

That is, the Zener diode 3 and the resistor R3
The voltage of the main electrode power supply 7 is divided in a series circuit with
An appropriate voltage is supplied to the gate G1 of the SIT.

The basic circuit operation principle is the same as that of the first embodiment, and a description thereof will be omitted. The circuit configuration of the second embodiment is such that the MOSFET 2 is the main component in the SIT 1, but the MOSFET 2 is replaced by an IGBT.
The same effect can be obtained by replacing with.

As described above, according to the power semiconductor device of the present invention, the semiconductor device is a semiconductor device using a normally-on type SIT as a main device. Easy to do and SIT
It is possible to provide a power semiconductor device capable of fully utilizing the performance of the power semiconductor device.

In this embodiment, SIT, MO
An SFET, a Zener diode, and the like are prepared as single components, and each is externally connected to configure the semiconductor device 6b. However, the power semiconductor device according to the present invention includes a device for connecting chip components and the like in the same unit, a semiconductor manufacturing process. The above functions may be formed on the same semiconductor substrate.

[0037]

As described above, according to the present invention, it is possible to provide a power semiconductor device in which the difficulty of handling the conventional SIT is improved, the driving can be easily performed, and the performance of the SIT can be fully utilized. Can be.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a power semiconductor device according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a power semiconductor device according to another embodiment of the present invention.

FIG. 3 shows a SIT in a power semiconductor device according to the present invention.
FIG. 4 is a diagram showing an example of a gate-source voltage and a gate current waveform of FIG.

FIG. 4 is a diagram showing an example of output current and voltage waveforms (main electrode waveforms) in the power semiconductor device according to the present invention.

FIG. 5 is a circuit diagram showing an SIT and a driving circuit thereof.

FIG. 6 is a diagram showing an example of a cascode connection between an SI thyristor and a MOSFET.

[Explanation of symbols]

Reference Signs List 1 SIT 2 MOSFET 3 Zener diode 4 DC power supply 4a Positive electrode of DC power supply 4b Negative electrode of DC power supply 5 Diode 6a, 6b Semiconductor device 7 Power supply for main electrode 8 SIT 9 Drive circuit 10 Normally off type by cascode connection of SI thyristor and MOSFET Composite semiconductor 11 SI thyristor 12 MOSFET 13 Zener diode A3 Zener diode anode A5 Diode anode D1 SIT drain D2 MOSFET drain G1 SIT gate G2 MOSFET gate K3 Zener diode cathode K5 Diode cathode S1 SIT source S2 MOSFET Source of R1, R2, R3 Resistance

Claims (5)

[Claims] 1. A power semiconductor device comprising an electrostatic induction transistor, an insulated gate field effect transistor, a Zener diode, a diode, and a DC power supply as main components. And the drain of the insulated gate field effect transistor are connected in series, the gate of the electrostatic induction transistor is connected to the cathode of the Zener diode, and the anode of the Zener diode is connected to the insulated gate field effect transistor. A power semiconductor device, wherein the DC power supply is connected to a source and both ends of the Zener diode via diodes. 2. The power semiconductor device according to claim 1, wherein a positive electrode of the DC power supply is connected to a cathode of the Zener diode via a diode, and a negative electrode of the DC power supply is connected to an anode of the Zener diode. The power semiconductor device according to claim 1, wherein 3. The power semiconductor device has a configuration in which the electrostatic induction transistor, the insulated gate field effect transistor, a Zener diode, a diode, and a DC power supply are externally connected. The power semiconductor device according to claim 1 or 2, wherein 4. The power semiconductor device, wherein the static induction transistor, the insulated gate field effect transistor, a Zener diode, a diode, and a DC power supply are arranged in a same unit, and the components are The power semiconductor device according to claim 1 or 2, wherein the power semiconductor device is connected. 5. The power semiconductor device has a configuration in which the static induction transistor, an insulated gate field effect transistor, a Zener diode, a diode, and a DC power supply are formed on the same semiconductor substrate. The power semiconductor device according to claim 1, wherein: