JPH0677798A - Delay type semiconductor relay - Google Patents

Abstract

PURPOSE:To set the delay time to an optimum value in accordance with the classification and the use condition of a load. CONSTITUTION:A light emitting element 1 and a photoelectric element 2 face opposite to each other. An auxiliary switch element 4 consisting of a depletion MOSFET which has the gate and the drain connected is provided between both ends of the photoelectric element 2. A variable resistance VR1 is connected between the gate and the source of the auxiliary switch element 4. A variable resistance VR2 is connected in series between the drain and the source of the auxiliary switch element 4, and this series circuit is connected between the gate and the source of a main switch element 3 consisting of a MOSFET. Since variable resistances VR1 and VR2 are inserted to the charging route and the discharging route of the capacity component of the main switch element 3, the rising period of time the falling period of time of the main switch element 3 can be controlled in accordance with the load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a delay type semiconductor relay in which a light emitting element and a photoelectric element are optically coupled to each other and a switch element composed of a MOSFET is turned on / off by the output of the photoelectric element.

[0002]

2. Description of the Related Art Conventionally, as a semiconductor relay of this type, as shown in FIG. 7, a light emitting element 1 such as a light emitting diode and a photoelectric element 2 in which a plurality of photodiodes, solar cells and the like are connected in series are provided. There has been proposed a configuration in which the main switch element 3 is turned on / off by using the photovoltaic power of the photoelectric element 2 in a pair. Main switch element 3 is MOSFE
The sources of _two switch elements Q ₁ and Q _{2 made} of T are connected to each other, and the drains of the switch elements Q ₁ and Q ₂ are connected to serve as an output terminal To. That is, the two switch elements Q ₁ and Q ₂ are symmetrically connected so that no directivity occurs in the energization direction between the output terminals To.

By the way, a series circuit of a photoelectric element 2 and two resistors R ₁ and R ₂ is connected between the gate and source of the main switching element 3. Further, a depletion type MOS is provided between the connection point of the resistors R ₁ and R ₂ and the positive electrode of the photoelectric element 2.
The drain and source of the auxiliary switch element 4 composed of an FET are connected. The resistor R ₁ is connected between the gate and the source of the auxiliary switch element 4, and the gate voltage is applied to the auxiliary switch element 4 by the voltage across the resistor R ₁ .

In such a connection relationship, when the light emitting element 1 is lit by energizing the input terminals Ti connected to both ends of the light emitting element 1, a current flows through the auxiliary switch element 4 due to the electromotive force of the photoelectric element 2. When the gate voltage is applied to the auxiliary switch element 4 by the voltage across the resistor R _1, the auxiliary switch element 4 is turned off, and the main switch element 3 is applied with the gate voltage due to the photovoltaic power of the photoelectric element 2 and the main switch element 3 is turned on. The element 3 is turned on. Here, the main switch element 3 is assumed to be configured by an enhancement type MOSFET.

By the way, since the main switch element 3 and the auxiliary switch element 4 are composed of MOSFETs, a capacitance component exists between the gate and the source. Further, since the main switch element 3 handles a larger amount of electric power than the auxiliary switch element 4, it also has a large capacitance component. Therefore, when an electromotive force is obtained from the photoelectric element 2 and a current flows through the resistor R ₁ , the capacitance component of the auxiliary switch element 4 is _first charged through the resistor R ₁ and the potential between the gate and the source rises. As the temperature rises, the drain-source of the auxiliary switch element 4 shifts to the off direction. When the impedance between the drain and source of the auxiliary switch 4 becomes sufficiently high, a current also flows between the gate and source of the main switch element 3, and the capacitance between the gate and source of the main switch element 3 is passed through both resistors R ₁ and R _2. The ingredients will be charged. Therefore, the main switching element 3
Shifts to the ON direction as the potential between the gate and the source rises. When the capacitance component between the gate and the source is sufficiently charged, the main switch element 3 is completely turned on. While the main switch element 3 is on, the gate voltage is applied to the auxiliary switch element 4 by the voltage generated across the resistor R ₁ , and the auxiliary switch element 4 is kept in the off state.

On the other hand, when the light emitting element 1 is turned off, no electromotive force is generated from the photoelectric element 2 and no voltage is generated across the resistor R _1.
The residual charge due to the capacitive component between the sources is discharged through the resistor R ₁ . When the residual charge is discharged, the auxiliary switch element 4 is turned on, and thereafter, the residual charge due to the capacitance component between the gate and the source of the main switch element 3 is reduced to the auxiliary switch element 4.
And discharged through resistor R ₂ . Therefore, the main switch element 3 shifts to the off direction while the residual charge is discharged, and when fully discharged, the main switch element 3 is completely turned off.

In short, as shown in FIG. 8 (a), from the time when the light emitting element 1 is turned on at the time t ₁ until the main switch element 3 is completely turned on, as shown in FIG. 8 (b). There is a certain time delay (hereinafter referred to as ON delay time Ton), and the main switching device 3 shifts from OFF to ON in the rising period Tr after the auxiliary switching device 4 is turned OFF in the ON delay time Ton. Of. Further, as shown in FIG. 8A, when the light emitting element 1 is turned off at time t ₂ and the main switching element 3 is completely turned off,
There is a time delay (hereinafter referred to as OFF delay time Toff) as shown in (b), and the main switch element 3 is turned on during the falling period Tf after the auxiliary switch element 4 is turned on in the off delay time Toff. From the off direction.

As described above, there is a rising period Tr and a falling period Tf for turning on and off, and the impedance between both ends of the main switching element 3 gradually changes during this period, so that the main switching device 3 is connected to the output terminal To. There is a possibility that it can be used for applications such as suppressing the inrush current flowing in the load and the occurrence of back electromotive force.

[0009]

However, since the inrush current and the back electromotive voltage change depending on the type of load and the operating conditions, the values of the resistors R ₁ and R ₂ should be changed according to the type of load and the power capacity of the load. It is necessary to change it, and if the conventional structure described above is used for this purpose, the resistance value will be set according to the load at the production stage. Therefore, the resistance value must be set for each product, and there is a problem that product type management becomes troublesome. Even if many kinds are prepared, the resistance R
_Since the values of ₁ and R ₂ can only be set in multiple stages, it is only possible to select the one with the delay time closest to the optimum value according to the type of load and the operating conditions, and in the end, the purpose is sufficient. There is a problem that cannot be achieved.

An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a delay type semiconductor relay in which the delay time can be set to an optimum value according to the type of load and the operating conditions. is there.

[0011]

According to the invention of claim 1, in order to achieve the above-mentioned object, a photovoltaic device composed of a light-emitting element and a photoelectric element arranged in opposition and a MOSFET is applied between a gate and a source. The main switch element that is turned on / off according to lighting or extinction of the light emitting element, the auxiliary switch element composed of a depletion type MOSFET in which the gate and the drain are connected between both ends of the photoelectric element, and the auxiliary switch. A first time setting resistor connected between the gate and source of the element and a series circuit between the drain and source of the auxiliary switching element connected between the gate and source of the main switching element for the second time setting A resistor is provided inside the package, and the first time setting resistor and the second time setting resistor are variable resistors and the adjustment knob is exposed to the outer surface of the package. Is are you.

In a second aspect of the invention, the first time setting resistor is a series circuit of a first resistor which is a fixed resistor and a second resistor which is a variable resistor, and comprises a light emitting element, a photoelectric element and an auxiliary element. A third package containing a first package containing a switch element and a first resistor, a second package containing a main switch element, a second resistor and a second time setting resistor.
And the adjustment knobs for the second resistance and the second time setting resistance are exposed on the outer surface of the third package.

[0013]

According to the first aspect of the invention, the time setting resistors for determining the delay time are variable resistors and the adjusting knobs of the variable resistors are exposed on the outer surface of the package. Thus, the delay time can be adjusted to the optimum value, and the inrush current and the counter electromotive voltage can be suppressed.

According to another aspect of the present invention, the first time setting resistor is a series circuit of the first resistor which is a fixed resistor and the second resistor which is a variable resistor, and the light emitting element, the photoelectric element, and the auxiliary switch element. , The first resistor is housed in the first package, the main switch element is housed in the second package, and the second resistor and the second time setting resistor are housed in the third package. If three packages are used and connected in the connection relationship as defined in claim 1, delay operation becomes possible,
If only the first package and the second package are used, it can be used as a semiconductor relay that does not perform delay operation. That is, a combination of three types of packages enables a plurality of types of usage methods, and the usage applications are expanded. Further, when a failure occurs, a part of the package may be replaced instead of replacing the whole package, so that the replacement cost is reduced as compared with the conventional configuration.

[0015]

(Embodiment 1) In this embodiment, as shown in FIG. 1, the resistors R ₁ and R ₂ of the conventional configuration shown in FIG. 7 are replaced by variable resistors VR ₁ and VR ₂ , respectively. . Figure 7
In the conventional configuration, the rising period T of the main switch element 3 is
Since r is determined by the resistances R ₁ and R _2, and the falling period Td of the main switch element 3 is determined by the resistance R ₂ , the resistances R ₁ and R ₂ are set to the variable resistances VR ₁ ,
In this embodiment, which is replaced with VR ₂ , variable resistors VR ₁ , V
By adjusting R ₂ , the rising period Tr and the falling period Td can be adjusted.

That is, a signal as shown in FIG. 2A is input to the light emitting element 1, and the light emitting element 1 is turned on (ON).
When turned off (OFF), the main switch element 3 is shown in FIG.
The variable resistors VR ₁ and VR ₂ are operated so as to perform the operation shown in (b).
Is set. Here, the variable resistor VR ₁
If the resistance value of is increased, the rising period Tr becomes longer as shown in FIG. 2C, and if the resistance value of the variable resistor VR ₂ is increased, the falling period Td becomes longer as shown in FIG. 2D. Of.

By adjusting the rising period Tr and the falling period Td in this way, it becomes possible to suppress the inrush current and the counter electromotive voltage. Here, when setting the rising period Tr and the falling period Td so as to suppress the inrush current and the back electromotive voltage, the variable resistance VR ₁ , while checking the waveform of the load current with an oscilloscope or the like,
VR ₂ may be adjusted. The delay type semiconductor relay having such a circuit configuration is housed in a DIP type package for an integrated circuit, and the adjustment knobs of the variable resistors VR ₁ and VR ₂ project from the upper surface of the package. The operation is similar to the conventional technique.

As described above, the variable resistor VR ₂ determines the fall period Td of the main switch element 3 and is only required to be inserted in the discharge path of the residual charge.
It may be inserted at points A and B in FIG. If inserted in these places, the variable resistor VR ₂ is not inserted in the charging path to the capacitance component of the main switch element 3, so the rising period T
r is set only by the variable resistor VR ₁ , and the falling period Td
Can be set only by the variable resistor VR ₂ .
Adjustment is easy.

(Embodiment 2) In this embodiment, as shown in FIG. 3, a light emitting element 1, a photoelectric element 2, an auxiliary switch element 4,
The two variable resistors VR ₁ and VR ₂ and the main switch element ₃ are housed in separate packages P ₁ , P ₂ and P ₃ , respectively. That is, in the first embodiment, all the circuits are housed in one package, whereas in this embodiment, three packages P ₁ , P ₂ , and P ₃ are used. Each package P ₁ , P ₂ , P ₃ has a DI with 6 terminals.
It is formed in a P-type.

The package P ₁ has two terminals which are input terminals Ti to the light emitting element 1, three terminals which are respectively connected to the source, the gate and the drain of the auxiliary switch element 4, and the remaining one terminal. Is not connected to anything. In the package P _2, and both the variable resistor VR _1, 3 single terminals respectively connected to three places with connection points at both ends and both the variable resistor VR _1, VR ₂ of the series circuit of VR _2, are electrically connected to each other 2 terminals and one terminal to which nothing is connected. Furthermore, the package P
₃ is an output terminal T connected to one terminal connected to the gate and to the drains of the respective switching elements Q ₁ and Q _2.
It has two terminals that are o and three terminals that are commonly connected to the sources. In FIG. 3, the terminals are represented by white circles. By providing the above-mentioned terminals to the _three packages P ₁ , P ₂ and P ₃ respectively, the same circuit as that of the first embodiment can be configured as shown in FIG. 3 by connecting the terminals. Can be done. Here, on the upper surface of the package P _2, as shown in FIG. 4, the variable resistor VR _1,
VR ₂ adjusting knobs v ₁ and v ₂ are provided in a protruding manner.

In the configuration of this embodiment, the rising period Tr
If it is not necessary to adjust the falling period Td, a fixed resistor can be used instead of using the package P ₂ . Further, if a resistor for turning on the auxiliary switch element 4 is connected to the outside without using the package P ₂ ,
It is also possible to configure a semiconductor relay that does not perform the delay operation. In other words, multiple combinations can be used by changing the combination method. Other configurations are the same as those in the first embodiment.

(Embodiment 3) This embodiment is different from Embodiment 2 in that a resistor R ₃ is connected to the gate of the auxiliary switch element 4 for the package P ₁ as shown in FIG. That is, the resistor R ₁ of the conventional configuration shown in FIG. 7 is replaced with a series circuit of a variable resistor VR ₁ and a resistor R ₃ .

In this structure, the same operation as in the first embodiment is performed due to the connection relationship shown in FIG. Also,
As shown in FIG. 6, if the package P ₂ is not used, a semiconductor relay that does not perform delay operation can be configured. Since the resistor R ₃ for applying a bias to the auxiliary switch element 4 is built in the package P ₁ , there is no need to use the resistor R ₃ separately, and the delay operation is not performed. There is an advantage that an external resistor is unnecessary as compared with. In short, either a delay type semiconductor relay or a non-delay type semiconductor relay can be configured by selecting whether or not to use the package P ₂ . Other configurations are similar to those of the second embodiment.

[0024]

According to the first aspect of the present invention, the time setting resistors for determining the delay time are variable resistors, and the adjustment knobs of the variable resistors are exposed to the outer surface of the package. The effect that the delay time can be adjusted to an optimum value according to the type and the use condition, and the inrush current and the back electromotive force can be suppressed.

According to a second aspect of the present invention, the first time setting resistor is a series circuit of a first resistor which is a fixed resistor and a second resistor which is a variable resistor, and a light emitting element, a photoelectric element and an auxiliary switch element. , The first resistor is housed in the first package, the main switch element is housed in the second package, and the second resistor and the second time setting resistor are housed in the third package. As a semiconductor relay that does not perform a delay operation by using only the first package and the second package, it is possible to perform a delay operation by connecting the three packages in the connection relationship as in the configuration of claim 1. The effect is that it can be used. That is, a combination of three types of packages enables a plurality of types of usage methods, which has the advantage of expanding the usage.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment.

FIG. 2 is an operation explanatory diagram of the first embodiment.

FIG. 3 is a circuit diagram showing a second embodiment.

FIG. 4 is a perspective view of a package containing a variable resistor used in a second embodiment.

FIG. 5 is a circuit diagram showing a usage pattern of the third embodiment.

FIG. 6 is a circuit diagram showing another usage pattern of the third embodiment.

FIG. 7 is a circuit diagram showing a conventional example.

FIG. 8 is an operation explanatory diagram of a conventional example.

[Explanation of symbols]

1 light emitting element 2 photoelectric element 3 main switching element 4 auxiliary switching element P ₁ package P ₂ package P ₃ package Ti input terminal To output terminal VR ₁ variable resistance VR ₂ variable resistance v ₁ adjustment knob v ₂ adjustment knob

Claims (2)

[Claims] 1. A light emitting element and a photoelectric element, which are placed opposite to each other,
There is a main switch element consisting of a MOSFET, which is turned on / off according to lighting / extinction of the light emitting element by applying the photoelectromotive force of the photoelectric element between the gate and the source, and between the gate and the drain between both ends of the photoelectric element. The main switch is a series circuit including an auxiliary switch element composed of a connected depletion type MOSFET, a first time setting resistor connected between the gate and source of the auxiliary switch element, and the drain and source of the auxiliary switch element. A second time setting resistor connected between the gate and source of the device is provided in the package, and the first time setting resistor and the second time setting resistor are variable resistors and the adjustment knob is A delay-type semiconductor relay characterized by being exposed on the outer surface. 2. The first time setting resistor is a series circuit of a first resistor, which is a fixed resistor, and a second resistor, which is a variable resistor, and includes a light emitting element, a photoelectric element, an auxiliary switch element, and a first resistor.
A first package accommodating the second resistor, a second package accommodating the main switch element, a second resistor and a second package
And a third package accommodating the time setting resistor of the third package, wherein the second resistor and the adjusting knob of the second time setting resistor are exposed on the outer surface of the third package. Item 3. A delay type semiconductor relay according to item 1.