JP2000196430A - Switch circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct desired on / off operations even without the need for input of a control signal to a switch circuit at all times in the case that the switch circuit is mounted on a device such as a rocket to which shock and vibration is exerted. SOLUTION: A thyristor 3 is used to maintain an ON-state of a photo MOS relay 1 without the consecutive application of a control signal to an input terminal 2. When a switch on-signal is given to the input terminal 2 and the thyristor 3 is once switched on, the photo MOS relay 1 is kept ON and it is not required to input a control signal to the input terminal 2 to keep this on-state at all times. On the other hand, when a switch-off signal is given to an input terminal 6, a photocoupler 7 is conductive and an input current from a TR 8 to the thyristor 3 is interrupted. Then power supply from the thyristor 3 to input side 4 of the photo MOS relay 1 is interrupted and an output side 5 of the photo MOS relay 1 is nonconductive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch circuit, and more particularly to a switch circuit mounted on a device such as a rocket which is subjected to vibration or impact.

[0002]

2. Description of the Related Art Conventionally, a mechanical latching relay (balanced armature type relay) has been used as a power supply switch for a device mounted on a rocket or the like. The mechanical latching relay has a very small loss at the contact portion and is very suitable for switching a large current.

The conventional power supply switch will be described with reference to FIG. As shown in the figure, the contact of the conventional power supply switch changes from an off state (a state indicated by a broken line) to an on state (a state indicated by a solid line) in response to input of a control signal. By changing to the ON state, the power applied between the hot terminal HOT and the return terminal is derived from the output terminal OUT. When the input of the control signal ends, the contact is turned off again, and the derivation of the power supply from the output terminal OUT ends. In other words, the switch shown in the figure operates as a mechanical latching relay.

However, in the above-mentioned mechanical latching relay, since the relay contacts are switched by a mechanical opening and closing operation, there is a possibility that the relay contacts may be inverted or chatter may occur due to vibration or impact when the rocket is launched. . Then, the supply of power to the device to be supplied with power is cut off (when the relay contact is inverted), or the supply of power to the device to be supplied with power is cut off (the relay contact stops chattering). If awakened). When such a power supply interruption or an instantaneous interruption occurs, the mission may be greatly affected. Therefore, it is necessary to take sufficient measures for environmental resistance, reliability, stability, durability and the like.

[0005]

A switch which does not perform a mechanical switching operation is disclosed in Japanese Patent Laid-Open No. 3-128.
524 and JP-A-62-242415. First, as shown in FIG. 3, a semiconductor relay described in Japanese Patent Application Laid-Open No. 3-128524 includes a light emitting diode LED that emits light in response to a drive current input, and an output light of the light emitting diode LED. Photodiode PD that receives light, and the photodiode PD
A resistor R and a MOSFET (Metal
Oxide Semiconductor Field Effect Transistor) Q1
And Q2. The MOSFET Q1 is turned on and off according to the on / off of the driving current of the light emitting diode.
Is turned on and off between the drain and source.
That is, the drive current of the light emitting diode is used as an on / off control signal, and the switch is turned on while the control signal is being input.

The optical switch described in Japanese Patent Application Laid-Open No. 62-242415 has a photodiode array D2 and a power MOSFET, as shown in FIG.
And TQ2. In the non-contact relay using the photoelectric element and the power MOSFET, the output voltage of the optical switch control circuit A is switched between high and low, thereby transmitting and blocking the optical signal of the optical waveguide by the optical fiber. is there.

In the prior art described in each of the above publications, since no mechanical operation is performed, it is possible to cope with vibrations and impacts during launching of a rocket. However, the switches described in each publication are turned on only when a control signal is being input, and are turned off when the input of the control signal is completed. Therefore, in order to maintain the ON state, the control signal must be constantly input. Therefore, there is a disadvantage that power consumption is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described drawbacks of the prior art, and has as its object to provide a switch circuit capable of performing a desired on / off operation without constantly inputting a control signal. That is.

[0009]

SUMMARY OF THE INVENTION A switch circuit according to the present invention is a switch circuit mounted on a device such as a rocket that is subjected to vibration or impact, and keeps on in response to a switch-on command. An ON state continuation circuit, including an ON state release circuit that releases the ON state continued by the ON state continuation circuit in response to an OFF command,
An input signal is output in the on state. The on-state continuation circuit includes a thyristor that turns on in response to a trigger input, and the on-command is used as the trigger. Further, the on-state continuation circuit further includes a photo-MOS relay that outputs the input signal when the thyristor is on.

Further, the on-state release circuit includes a transistor which is turned off in response to the off command and turns off the input to the thyristor.
Further, the on-state canceling circuit further includes a photocoupler that is turned on in response to the off command, and the transistor is turned off when the photocoupler is on. . The input signal is a power supply to be supplied to the device.

In short, the present switch circuit uses a thyristor and maintains the ON state of the photoMOS relay without inputting a control signal. When a switch-on signal is input to the input terminal and the switch is turned on once, the photoMOS relay is held in an on state (conductive state). Therefore, a control signal is always input to hold this on state. There is no need to continue.

On the other hand, when the switch-off signal is input to turn on the photocoupler 7, the input to the thyristor is turned off. Then, the power supply from the thyristor to the input side of the photo MOS relay is cut off, and the conduction between the input terminal and the output terminal on the output side of the photo MOS relay becomes non-conductive.

[0013]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the same parts as those in the other drawings are denoted by the same reference numerals.

FIG. 1 is a block diagram showing an embodiment of a switch circuit according to the present invention. In the figure, the switch circuit according to the present embodiment is turned on when a predetermined voltage is applied to the gate terminal and the photoMOS relay 1 in which the output side 5 is connected to the power supply HOT terminal and the input side 4 is connected to the power supply RTN terminal. The thyristor 3 is configured to include a thyristor 3 which is turned off when the state is turned off and an input is cut off, a transistor 8 for turning off the input to the thyristor 3, and a photocoupler 7 for turning on the transistor 8. The input terminal 2 is an ON control signal input terminal, and the input terminal 6
Is an OFF control signal input terminal.

In this configuration, in order to turn on the semiconductor power switch, the ON control signal input terminal 2
A semiconductor power switch-on signal is input. This allows
A predetermined voltage is applied to the gate terminal of the thyristor 3 via the transformer T or the like, and the thyristor 3 is turned on. That is, the semiconductor power switch-on signal is a trigger signal for turning on the thyristor 3. Thereafter, power is continuously supplied to the input side 4 of the photoMOS relay 1 due to the operation characteristics of the thyristor 3. Therefore, the photo M
The input terminal IN and the output terminal OU on the output side 5 of the OS relay 1
T is electrically connected. That is, the switch is turned on, and this on state is continued.

On the other hand, to turn off the semiconductor power switch, a semiconductor power switch off signal is input to the control signal input terminal 6 for turning off. Thereby, the photocoupler 7
Is turned on, and the input current from the transistor 8 to the thyristor 3 is turned off. Then, the power supply from the thyristor 3 to the input side 4 of the photo MOS relay 1 is cut off. Therefore, the connection between the input terminal IN and the output terminal OUT on the output side 5 of the photoMOS relay 1 becomes non-conductive. That is, the continuation of the ON state of the switch is released and the switch is turned OFF.

As described above, in this circuit, the thyristor 3 is used in addition to the transistor, and the ON state of the photoMOS relay 1 is maintained without inputting a control signal. Then, when a switch-on signal is input to the input terminal 2 and the switch is turned on once, the photoMOS relay 1 is held in the on state (conductive state). In addition, since it is not necessary to constantly input a control signal in order to maintain the ON state, power consumption can be reduced as compared with the related art in which a control signal needs to be constantly input.

In the above-described embodiment, the case where the switch circuit is used for equipment mounted on a rocket has been described.
Obviously, the present invention can be applied to a switch circuit mounted on a device subjected to vibration or shock.

It is apparent that the present invention can be widely applied to not only the case where the power supply is turned on and off but also the case where a general signal is turned on and off.

[0020]

As described above, the present invention employs a thyristor, and a photo MOS transistor without inputting a control signal.
By maintaining the ON state of the relay, there is no need to constantly input a control signal in order to maintain the ON state, and there is an effect that power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a switch circuit according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a conventional switch circuit.

FIG. 3 is a diagram illustrating a configuration of a conventional switch circuit.

FIG. 4 is a diagram showing a configuration of a conventional switch circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PhotoMOS relay 2 Control signal input terminal for ON 3 Thyristor 6 Control signal input terminal for OFF 7 Photocoupler 8 Transistor

Claims (6)

[Claims] 1. A switch circuit mounted on a device, such as a rocket, to which vibration or impact is applied, comprising: an on-state continuation circuit for continuing an on-state in response to a switch-on command; And an on-state release circuit for releasing an on-state continued by the on-state continuation circuit, and outputting an input signal in the on-state. 2. The switch circuit according to claim 1, wherein the on-state continuation circuit includes a thyristor that turns on in response to a trigger input, and the on-command is used as the trigger. 3. The switch circuit according to claim 1, wherein the on-state continuation circuit further includes a photo-MOS relay that outputs the input signal when the thyristor is on. 4. The thyristor according to claim 1, wherein the on-state release circuit includes a transistor which is turned off in response to the off command and turns off an input to the thyristor.
4. The switch circuit according to any one of claims 1 to 3. 5. The on-state release circuit further includes a photocoupler that is turned on in response to the off command, wherein the transistor is turned off when the photocoupler is on. Claims 1-4
The switch circuit according to any one of the above. 6. The switch circuit according to claim 1, wherein the input signal is a power supply to be supplied to the device.