JPH01158821A - Latching type semiconductor relay - Google Patents

Abstract

PURPOSE:To attain the changeover of the conductive state and the nonconductive state by the application of a pulse signal by employing the series combination of a normally-ON transistor(TR) and a photo thyristor. CONSTITUTION:The relay is provided with the photo thyristor 3 triggered by an optical signal, the normally-ON TR 5 connected in series therewith, and a photovoltaic element 4 connected between control electrodes of the TR 5 to bias the TR 5 into the turn-off state in the reception of the optical signal. When a pulse signal for turn-on is given between input terminals I1 and I2, a light emitting element 1 generates the optical signal, the photo thyristor 3 is triggered, and the photo thyristor 3 keeps the turn-on-state even if the optical signal is lost and the load current flows continuously. The turn-off pulse signal is applied between input terminals I3 and I4. Thus, the changeover of the conductive state and the nonconductive state is attained by the application of the pulse signal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a latching type semiconductor relay for direct current power control.

(Background Art) FIG. 3 is a circuit diagram showing the configuration of a conventional semiconductor relay for controlling DC power. There is an LED between input terminals I, I2.
A light emitting element 1 consisting of the following is connected. This light emitting element 1
The emitted optical signal is received by the phototransistor 10. The light reception output of the phototransistor 10 is inputted between the base and emitter of the power transistor 12 via the drive circuit 11. Output terminals 01 and 0□ are connected to the collector and emitter of the power transistor 12, respectively.

In this conventional example, since a normally-off type normal transistor 12 is used as an output element, the output terminals 0 + and 02 are connected only during the period when an input signal is present.
When the input signal disappears, the output terminals 0 + and 02 become non-conductive. therefore,
It has not been possible to realize a latching type semiconductor relay that switches between a conductive state and a non-conductive state by applying a pulse signal.

(Object of the invention) The present invention has been made in view of the above points, and
Its purpose is to create a latching-type semiconductor relay that uses a combination of a flexible thyristor and a normally-on transistor in series to enable switching between a conductive state and a non-conductive state by applying a pulse signal. Our goal is to provide the following.

(Disclosure of the Invention) In order to achieve the above object, the latching type semiconductor relay according to the present invention includes a photothyristor 3 that is triggered by an optical signal, and a photothyristor 3 that is triggered by an optical signal. a normally-on transistor 5 connected in series with the transistor 3; a photovoltaic element 4 connected between the control electrode of the transistor 5 and biasing the transistor 5 to an off state when receiving an optical signal; A first light emitting element 1 that irradiates an optical signal to the photothyristor 3, and a second light emitting element 2 that irradiates an optical signal to the photovoltaic element 4.
It is characterized by comprising the following.

In FIG. 1, input terminals It and I2 are turn-on pulse input terminals, to which a light emitting element 1 consisting of an LED is connected. Input terminals I3,1. is a turn-off pulse input terminal, to which a light emitting element 2 made of an LED is connected. The light emitting element 1 is optically coupled to a photothyristor 3, and the light emitting element 2 is optically coupled to a photovoltaic element 4.

The photothyristor 3 is a thyristor triggered by an optical signal, and once turned on, it remains on unless the anode-cathode current is interrupted. The anode of the photothyristor 3 is connected to the output terminal 01. The gate of the photothyristor 3 is connected to the output terminal 02 via a resistor 7. This suppresses fluctuations in the gate potential of the photothyristor 3. The cathode of the photothyristor 3 is connected to the output terminal 02 via the drain and source of a normally-on transistor 5. The normally-on transistor 5 is
For example, depletion type JFET, MOSFET,
When a bias voltage is not applied between the gate and source, the drain and source are in a conductive state, and when the bias voltage is applied, the drain and source are in a non-conductive state. . The output of the photovoltaic element 4 is connected between the gate and source of this transistor 5. A resistor 6 is connected in parallel to both ends of the photovoltaic element 4 . This resistor 6 is provided to discharge the charges remaining at both ends of the photovoltaic element 4 when the optical signal disappears. The photovoltaic element 4 is made up of photodiodes connected in series using p-n junctions, and the number of photodiodes connected in series is set such that it can generate a voltage sufficient to bias the normally-on transistor 5 to an off state. It is set. Note that output terminals 0, .
A series circuit of a load 8 and a DC power supply 9 is connected between the terminals 02 and 02.

FIG. 2 is an operational waveform diagram of the above circuit. As shown in the same figure (b), the turn-on pulse signal is input to the input terminals I, .
When electricity is applied between 12, the light emitting element 1 generates an optical signal,
The photothyristor 3 is triggered by this optical signal.

At this time, the normally-on transistor 5 is in the on state, so the DC power supply 9 connects the load 8 to the output terminal 01.
A current flows through a path returning to the DC power supply 9 via the photothyristor 3, the normally-on transistor 5, and the output terminal 02. If this current is larger than the holding current of the photothyristor 3, even if the optical signal (Fig. 2(b)) disappears, the photothyristor 3 will continue to be in the on state, and therefore, as shown in Fig. 2(,) As shown in , the load current continues to flow.

Next, as shown in FIG. 2(c), when a pulse signal for turn-off is applied between the input terminals I i I 4, the light emitting element 2 generates an optical signal, and this optical signal generates a photovoltaic force. Element 4 generates a photovoltaic force. By applying this photovoltaic force between the gate and source of the normally-on transistor 5, the drain and source of the transistor 5 become non-conductive. Therefore, photothyristor 3
The load current flowing through is cut off once. After that, the turn-on pulse signal (FIG. 2(C)) disappears, and the train of the normally-on transistor 5.
Even if the connection between the sources returns to the conductive state, the photothyristor 3 has already been turned off and will not turn on unless triggered again.

In this way, the semiconductor relay of the present invention can be switched between a conductive state and a non-conductive state by applying a pulse signal, and even after the pulse signal disappears, the conductive state or non-conductive state is maintained. It is something that can be done.

(Effects of the Invention) As described above, the present invention has a photothyristor and a normal
A photothyristor is used in combination with an on-type transistor in series, and the photothyristor is turned on by instantaneous tripping with an optical signal to maintain a conductive state, and a normally-on transistor is instantaneously turned off by an optical signal. This turns off the photothyristor and maintains it in a non-conducting state, so it can be switched between a conducting state and a non-conducting state by applying a pulse signal, making it a latching type semiconductor that can significantly reduce power consumption on the input side. This has the effect of realizing a relay.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is an operational waveform diagram of the same, and FIG. 3 is a circuit diagram of a conventional example. 1.2 is a light emitting element, 3 is a photothyristor, 4 is a photovoltaic element, and 5 is a normally-on transistor.

Claims (1)

[Claims] (1) A photothyristor that is triggered by an optical signal, a normally-on transistor connected in series with the photothyristor, and a normally-on transistor connected between the control electrode of the transistor and activated when receiving the optical signal. A photovoltaic element biased to an off state, a first light emitting element that irradiates an optical signal to the photothyristor, and a second light emitting element that irradiates an optical signal to the photovoltaic element. Characteristic latching type semiconductor relay.