WO2004114508A1

WO2004114508A1 - Ac switch

Info

Publication number: WO2004114508A1
Application number: PCT/JP2004/007200
Authority: WO
Inventors: Koichi Morita
Original assignee: Sanken Electric Co., Ltd.
Priority date: 2003-06-23
Filing date: 2004-05-20
Publication date: 2004-12-29
Also published as: JPWO2004114508A1; JP4123274B2

Abstract

An AC switch that is turned on and off by a control signal inputted thereto, thereby performing an on/off control of AC signals inputted between first and second terminals (11,12). The AC switch comprises a normally-on FET (Q1) having first and second main electrodes (21,22) connected to the first and second terminals (11,12), respectively and having a gate (G) to which a gate signal is inputted; and diodes (D1,D2) for inputting the gate signal of a gate signal part (13) between the gate (G) and one of the first and second terminals (11,12) which exhibits a lower potential.

Description

Description AC switch Technical field

The present invention relates to an AC switch that is turned on / off by a control signal and controls on / off of an input AC signal. Background art

A conventional AC switch used for a converter or a converter is shown in Fig. 1, for example. An AC signal from an AC power supply 110 is applied to both ends of a first terminal 11 and a second terminal 12 to an AC switch 100 shown in FIG.

The AC switch 100 includes a normally-off type MOS FE TQ4 (hereinafter abbreviated as FE TQ4) and an normally-off type, which are connected in reverse series at both ends of the first terminal 11 and the second terminal # 2. MO SFE TQ 5 (hereinafter abbreviated as FE TQ 5). The drain of FETQ4 is connected to the first terminal 11, the source of FETQ4 is connected to the source of FETQ5, and the drain of FETQ5 is connected to the second terminal 12. A gate signal composed of a pulse signal is applied from the gate signal section 13 to the gate of FETQ4 and the gate of FETQ5.

Next, the operation of the thus-configured AC switch 100 will be described. First, when the gate signal from the gate signal section 13 is applied to the gates of FETQ4 and FETQ5 at a positive voltage (for example, 10 V), both FETQ4 and FETQ5 become effective. .

Therefore, during the period when the gate signal is at a positive voltage, when a positive voltage is applied to the first terminal 11 from the AC power supply 110, a current flows from the first terminal 11 to the second terminal 12 When a positive voltage is applied to the second terminal 12 from the AC power supply 110, a current flows from the second terminal 12 to the first terminal 11. That is, FETQ4 and FETQ5 are connected in reverse series, and the drain of FETQ4 is connected to the first terminal 11. And the drain of FETQ 5 is connected to the second terminal 12, so that an AC current flows through the AC switch 100.

Next, when the gate signal from the gate signal section 13 is applied to the gate of the TQ 5 (24 and the TQ 5) at zero voltage, both the F 04 and the ETQ 5 are turned off. The current stops flowing at 100.

Thus, AC switch 100 can change the frequency of the current flowing through AC switch # 00 according to the frequency of the gate signal. Further, according to the AC switch 100, by using a common source, it is possible to control ON / OFF of the FETQ4 and the FETQ5 with one gate signal.

On the other hand, a triac may be used as an AC switch. However, although it can be turned on by applying a positive voltage gate signal to the triac, it cannot be turned off by applying a zero voltage gate signal to the triac. That is, the triac cannot be turned off unless the current flowing through the triac approaches zero. Therefore, when a triac is used, the frequency of the current flowing through the triac cannot be changed according to the frequency of the gate signal, and the triac is turned on / off at a frequency equal to or higher than the frequency of the AC power supply 110. I couldn't control the talent.

Japanese Patent Application Laid-Open No. 5-75110 discloses a technique related to the conventional AC switch. Disclosure of the invention

However, the conventional AC switch shown in FIG. 1 is not composed of one element but composed of two elements, FETQ4 and FETQ5. Also, since FETQ4 and FETQ5 are connected in series, the value obtained by adding the on-resistance of the two elements becomes the overall on-resistance, and the loss increases.

The present invention provides an AC switch that can reduce loss by controlling ON / OFF of an AC signal with one element, can be turned ON / OFF at a frequency higher than the power supply frequency, and can greatly reduce the size of an inverter or a comparator. It is in.

The present invention has been made to solve the above problems, and a main aspect of the present invention is that the first terminal and the second terminal are turned on / off by an input control signal. An AC switch for controlling on / off of an AC signal input therebetween, wherein the first terminal is connected to the first main electrode, the second terminal is connected to the second main electrode, and the control signal is input. A semiconductor switch to which a control electrode is connected, and control signal input means for inputting the control signal between the control electrode and a terminal having a low potential among the first terminal and the second terminal. Features. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a circuit diagram of a conventional AC switch.

FIG. 2 is a circuit diagram of the AC switch according to the first embodiment of the present invention. FIG. 3 is a circuit diagram of an AC switch according to the second embodiment of the present invention. FIG. 4 is a circuit diagram of an AC switch according to a third embodiment of the present invention. FIG. 5 is a circuit diagram of an AC switch according to a fourth embodiment of the present invention. FIG. 6 is a circuit diagram of an AC switch according to a fifth embodiment of the present invention. FIG. 7 is a circuit diagram of an AC switch according to a sixth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an AC switch according to an embodiment of the present invention will be described in detail with reference to the drawings.

(First Embodiment)

The AC switch according to the first embodiment is characterized in that the on / off control of the AC signal by one element reduces the re-loss and enables the switch to be turned on even at a frequency higher than the power supply frequency. FIG. 2 is a circuit diagram of the AC switch according to the first embodiment of the present invention.

In the AC switch shown in FIG. 2, a normal-marion FETQ 1 (hereinafter abbreviated as FETQ 1) is connected to both ends of the first terminal 11 and the second terminal 12, and the first main electrode 2 1, a second main electrode 22 and a gate G. The first main electrode 21 is connected to the first terminal 11, and the second main electrode 22 is connected to the second terminal 12. This normally-on type FETQ1 has a low on-resistance and a high breakdown voltage, and is made of, for example, a compound semiconductor such as SiC or GaN or a MESFET. In this normally-on type FETQ1, the drain and source are formed symmetrically. Therefore, the first main electrode 21 or the second main electrode 22 connected to the higher potential terminal between the〗 terminal 11 and the second terminal 12 becomes the drain and the lower potential terminal The other connected main electrode becomes the source.

Further, one end of a gate signal section 13 for generating a gate signal composed of a pulse signal or the like is connected to the gate G of the FETQ1. The cathode of the die D 1 is connected to the first main electrode 21 of the FET Q 1, and the cathode of the die D 2 is connected to the second main electrode 22 of the FET Q 1. The diode D1 anode and the diode D2 anode are connected to the other end of the gate signal section 13, and the connection point between the diode D1 anode and the diode D2 anode is connected to the FETQ1 anode. A gate signal is input to the gate G.

Next, the operation of the AC switch according to the first embodiment configured as described above will be described.

First, when an AC signal is input between the first terminal〗 1 and the second terminal 12, when the potential of the first terminal 11 is high and the potential of the second terminal 12 is low, the first The main electrode 21 serves as a drain, and the second main electrode 22 serves as a source. When a gate signal for setting the gate G to a higher potential or a zero potential with respect to the potential of the second main electrode 22 as a source is input, FETQ 1 is turned on, and the diode D 2 is turned on. Also, at this time, the diode D1 is turned off because it is in the reverse bias state.

Next, when the potential of the second terminal 12 is high and the potential of the first terminal 11 is low, the first main electrode 21 of the FETQ 1 becomes the source and the second main electrode 22 becomes the drain. You. When a gate signal for setting the gate G to a higher potential or a zero potential with respect to the potential of the first main electrode 21 as a source is input, FETQ 1 is turned on, and the diode D 1 is turned on. At this time, the diode D2 is turned off because it is in a reverse bias state.

Furthermore, even when the potential of the first terminal 11 is high and the potential of the second terminal 12 is low, and when the potential of the second terminal 12 is high and the potential of the first terminal 11 is low, the main electrode as the source is When a gate signal that sets the potential of the gate G lower than that of the gate is input, the FETQ 1 turns off. As described above, according to the AC switch according to the first embodiment, when an AC signal is input between the first terminal 11 and the second terminal 12, the potential of the first terminal 11 becomes the second terminal. 12 The potential is higher or lower than the potential of 2, but the terminal with the lower potential is selected by the diodes D 1 and D 2, and the terminal between the selected lower terminal (source) and the gate G is selected. Since the gate signal is input to the, the ON / OFF control of the AC signal can be controlled with one element of FETQ1. Therefore, the loss can be reduced, the power can be turned on / off at a frequency higher than the power supply frequency, and the inverter and the converter can be significantly reduced in size.

(Second embodiment)

FIG. 3 is a circuit diagram of an AC switch according to a second embodiment of the present invention. The AC switch according to the second embodiment is provided with FETQ2 and Q3 in place of the diodes D1 and D2 of the AC switch according to the first embodiment, and malfunctions due to noise and leakage current. The feature is that it prevented.

In FIG. 3, FE TQ2 and Q 3 are switches such as a normally-type MOS FET, and the drain of F ETQ 2 is connected to the first terminal 11 and the drain of FE TQ 3 is connected to the second terminal. Connected to terminal 12 '. The source of FETQ 2 and the source of FETQ 3 are connected to the other end of the gate signal section 13.

Also, the F gate (32 and ETQ 3) is turned on by inputting a positive voltage gate signal to the gate of the FET connected to the low potential terminal, and connected to the FET gate connected to the high potential terminal. It is turned off by inputting a negative voltage gate signal to the gate.

Next, the operation of the AC switch according to the second embodiment configured as described above will be described.

First, when the potential of the first terminal 11 is high and the potential of the second terminal 12 is low, the first main electrode 21 of the FETQ 1 becomes a drain and the second main electrode 22 becomes a source. A gate signal that sets the gate G higher or zero with respect to the potential of the second main electrode 22 as a source is input, and the gate is turned on by inputting a positive voltage gate signal to the gate of FETQ3. It is turned off by inputting a zero-voltage or negative-voltage gate signal to the gate of FETQ2. As a result, FETQ 1 turns on. Next, when the potential of the second terminal 12 is high and the potential of the first terminal 11 is low, the first main electrode 21 of the FETQ1 becomes a source and the second main electrode 22 becomes a drain. A gate signal that sets the gate G higher or zero with respect to the potential of the first main electrode 21 as a source is input, and a positive voltage gate signal is input to the gate of the FETQ 2. To turn on, and turn off by inputting a zero voltage or negative voltage gate signal to the gate of FETQ3. Therefore, FETQ 1 turns on. Furthermore, even when the potential of the first terminal 11 is high and the potential of the second terminal 12 is low, and when the potential of the second terminal 12 is high and the potential of the first terminal 11 is low, the main electrode as the source is When a gate signal that sets the potential of the gate G lower than that of the gate is input, the FETQ1 is turned off.

As described above, according to the AC switch according to the second embodiment, the same effect as that of the AC switch according to the first embodiment can be obtained, and the FETs Q2 and Q3 can be stably turned on. Malfunction due to noise or leakage current can be prevented.

(Third embodiment)

FIG. 4 is a circuit diagram of an AC switch according to a third embodiment of the present invention. The AC switch according to the third embodiment is characterized in that a current flows from a terminal having a high potential to a diode via a resistor to prevent malfunction due to noise or leakage current.

In FIG. 4, the same parts as those shown in FIG. 2 are denoted by the same reference numerals, and the description of the same parts will be omitted.

The anode of the diode D 3 is connected to the first terminal 11, and the cathode of the diode D 3 is connected to the anode of the diode D 1 and the diode D 1 via the resistor R 1.

2 connected to the anode. The terminal of diode D4 is connected to the second terminal 12 and the power source of diode D4 is connected to the diode via resistor R1.

It is connected to the anode of D1 and the anode of diode D2. Die codes D1 to D4 are configured as a bridge.

Next, the operation of the AC switch according to the third embodiment configured as described above will be described. Here, only the operation of the diodes D 1 and D 2 will be described. First, when the potential of the first terminal 11 is high and the potential of the second terminal 12 is low, the first main electrode 21 of the FETQ 1 becomes a drain and the second main electrode 22 becomes a source. At this time, a current flows through the first terminal 11 → the diode D 3 → the resistor R 1 → the diode D 2 → the second terminal 12. As a result, the diode D2 turns on and the diode D1 turns off.

Next, when the potential of the second terminal 12 is high and the potential of the first terminal 11 is low, the first main electrode 21 of FETQ 1 becomes a source and the second main electrode 22 becomes a drain. At this time, current flows through the second terminal 12 → diode D 4 → resistor R 1 → diode D 1 → first terminal 11. This turns on diode D1 and turns on diode D2.

As described above, according to the AC switch according to the third embodiment, the same effect as that of the AC switch according to the first embodiment can be obtained, and the die heads D 1 and D 2 can be stabilized. Because it can be turned on, malfunction due to noise and leakage current can be prevented.

(Fourth embodiment)

FIG. 5 is a circuit diagram of an AC switch according to a fourth embodiment of the present invention. The AC switch according to the fourth embodiment is characterized in that malfunction due to noise or leakage current is prevented.

In FIG. 5, the same parts as those shown in FIG. 2 are denoted by the same reference numerals, and the description of the same parts will be omitted. A resistor R1 is connected in parallel with the diode D1, and a resistor R2 is connected in parallel with the diode D2.

Next, the operation of the AC switch according to the fourth embodiment thus configured will be described. Here, only the operation of the diodes D 1 and D 2 will be described. First, when the potential of the first terminal 11 is high and the potential of the second terminal 12 is low, the first main electrode 21 of FETQ 1 becomes a drain and the second main electrode 22 becomes a source. At this time, current flows through the first terminal 11 → resistor R 1 → diode D 2 → second terminal 12. This turns on diode D2 and turns on diode D〗.

Next, when the potential of the second terminal 12 is high and the potential of the first terminal 11 is low, the first main electrode 2〗 of the FETQ〗 becomes the source and the second main electrode 22 becomes the drain. You. At this time, a current flows through the second terminal 12 → the resistor [¾ 2 → the capacitor 01 → the first terminal 11 ”. This turns on diode D1 and turns on diode D2.

As described above, according to the AC switch according to the fourth embodiment, the same effect as that of the AC switch according to the first embodiment can be obtained, and die switches D〗 and D 2 can be stabilized. Because it can be turned on, malfunction due to noise and leakage current can be prevented.

(Fifth embodiment)

FIG. 6 is a circuit diagram of an AC switch according to a fifth embodiment of the present invention. The AC switch according to the fifth embodiment is different from the AC switch according to the third embodiment shown in FIG. 4 in that a gate signal section 13 and a gate G of the FETQ 1 are further provided. DC power supply E is provided. The positive terminal of the DC power source E is connected to the gate G of the FETQ 1, and the negative terminal of the DC power source E is connected to one end of the gate signal section 13.

According to such a configuration, the DC voltage of the DC power supply E is always applied to the gate G of the FET Q1 as a bias voltage, so that the gate voltage shortage does not occur and the FET Q1 does not malfunction.

(Sixth embodiment)

FIG. 7 is a circuit diagram of an AC switch according to a sixth embodiment of the present invention. The AC switch according to the sixth embodiment is different from the AC switch according to the fourth embodiment shown in FIG. 5 in that a direct current is applied between the gate signal section 13 and the gate G of the FET GM. Power supply E is provided. The positive terminal of the DC power source E is connected to the gate G of the FETQ 1, and the negative terminal of the DC power source E is connected to one end of the gate signal section 13.

In the AC switches according to the third to sixth embodiments, the resistor R1 is used to pass a current. However, instead of the resistor R1, for example, a constant current element ゃ a constant current circuit is used. In such a case, a forward current can be stably passed from a low voltage to a high voltage. Industrial applicability

According to the present invention, when an AC signal is input between the first terminal and the second terminal, when the potential of the first terminal is high and the potential of the second terminal is low, the potential between the second terminal and the control electrode is reduced. When the control signal is input to the switch and the semiconductor switch is turned on, and the potential of the second terminal is high and the potential of the first terminal is low, the control signal is input between the first terminal and the control electrode. The semiconductor switch turns on. When the control signal is not input to the control electrode, the semiconductor switch is turned off. For this reason, an AC switch that can reduce the loss by controlling ON / OFF of the AC signal with one element, can be turned ON / OFF at a frequency higher than the power supply frequency, and can significantly reduce the size of the inverter / converter can be provided. .

Claims

The scope of the claims

(1) An AC switch that turns on and off by an input control signal and controls on / off of an AC signal input between a first terminal and a second terminal.

A semiconductor switch in which a first main electrode is connected to the first terminal, a second main electrode is connected to the second terminal, and a control electrode for inputting the control signal is connected, and the first terminal and the second terminal Control signal input means for inputting the control signal between a terminal having a low electric potential and the control electrode;

It is characterized by having.

2.The AC switch according to claim 1, wherein

The control signal input means,

A first diode in which one electrode is connected to the first main electrode of the semiconductor switch;

A second diode having one electrode connected to the second main electrode of the semiconductor switch and the other electrode connected to the other electrode of the first diode;

The control signal is inputted between the control electrode and a connection point between the other electrode of the first diode and the other electrode of the second diode.

3.The AC switch according to claim 2,

Current supply means for flowing a current from the higher potential terminal of the first terminal and the second terminal to the diode connected to the lower potential terminal;

Is further provided.

4.The AC switch according to claim 3,

The current supply means, A third diode and a resistor are connected in series between a connection point between the other electrode of the first die and the other electrode of the second die and the first terminal. Series circuit,

A fourth diode connected between the connection point of the third diode and the resistor and the second terminal;

It is characterized by having.

5 The AC switch according to claim 3,

The current supply means,

A first resistor connected in parallel to the first diode;

A second resistor connected in parallel to the second diode;

It is characterized by having.

6.The AC switch according to claim 4 or 5, wherein

And a DC power supply for applying a DC voltage to the control electrode of the semiconductor switch.

7.The AC switch according to claim 1, wherein

The control signal input means,

A first switch in which a first electrode is connected to the first main electrode of the semiconductor switch;

A second switch in which a third electrode is connected to the second main electrode of the semiconductor switch and a fourth electrode is connected to a second electrode of the first switch;

Has,

Inputting the control signal between the control electrode and a connection point between the second electrode of the first switch and the fourth electrode of the second switch;

Among the first switch and the second switch, a switch connected to the low potential terminal is turned on, and a switch connected to the high potential terminal is turned off. 8 an AC switch according to any one of claims 1 to 7, wherein the semiconductor Suitsuchi is, _c, which is a Suitsuchi of normally-

9 The AC switch according to claim 8,

The normal marion type switch is made of a compound semiconductor.