JP2003303536A - Relay driving device and relay device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relay driving device holding a contact position by applying voltage and a relay device both of which are inexpensive and have low power consumption. <P>SOLUTION: This relay driving device driving the relay by supplying current to a relay coil has a self-excited oscillation circuit conducting self-excited oscillation in cooperation with the relay coil by intermittently applying voltage to the relay coil; and a delay circuit which delays operation for the specified time until the self-excited oscillation circuit starts self-excited oscillation after current is supplied to the relay coil. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay drive device and a relay device, and more particularly to a relay drive device and a relay device that maintain a contact position by continuously applying a voltage.

Power saving is demanded for relay devices. Therefore, by supplying a pulse signal to the relay coil,
A relay driving method has been proposed in which the contact position is held by driving intermittently.

[0003]

2. Description of the Related Art FIG. 1 is a block diagram of an example of a conventional relay device, and FIG. 2 is an operation waveform diagram of an example of a conventional relay device. 2 (A) is a drive voltage of the relay coil, FIG.
(B) shows the current flowing through the relay coil.

The conventional relay device 1 includes a relay coil 1
1, diode 12, transistor 13, microcomputer 1
4 and the driver circuit 15.

First, the microcomputer 14 starts the process shown in FIG.
As shown in (A), a voltage is continuously applied to the relay coil 11 for A for a fixed time. When a voltage is continuously applied to the relay coil 11 for a certain time A, a rated current flows in the relay coil 11 as shown in FIG. When a rated current flows through the relay coil 11, a relay contact (not shown) is moved.

Next, at the time t1, as shown in FIG. 2A, the pulse voltage of the ON period B and the OFF period C is applied to the relay coil 11
Apply to. By applying the pulse voltage of the ON period B and the OFF period C to the relay coil 11,
A current equal to or higher than the holding current is supplied to the relay contact, and the relay contact (not shown) is held in a predetermined state.

FIG. 3 is a block diagram of another example of the conventional relay device, and FIG. 4 is an operation waveform diagram of another example of the conventional relay device. 4A shows an output pulse of the first pulse generating circuit, FIG. 4B shows an output pulse of the second pulse generating circuit, and FIG. 4C shows a current flowing through the relay coil.

The relay device 20 comprises a relay 21, a diode 22, a transistor 23, a resistor 24, a pulse generating circuit 25, and a time measuring circuit 26.

The relay 21 comprises a relay coil 31 and a relay contact 32. A diode 22 for absorbing a back electromotive force generated in the relay coil 31 is connected in parallel to the relay coil 31. Further, the collector-emitter of the transistor 23 is connected in series to the relay coil 31. The base of the transistor 23 is connected to the pulse generating circuit 25 via the resistor 24, and is switched by the pulse signal from the pulse generating circuit 25.

The pulse generating circuit 25 is composed of a first pulse generating circuit 41 and a second pulse generating circuit 42. As shown in FIG. 4A, the first pulse generation circuit 41 generates a pulse in which the ON period TON is longer than the OFF period TOFF. The second pulse generation circuit 42 is shown in FIG.
As shown in, the off period TOFF generates a longer pulse than the on period TON. When there is an output command from the outside at time t0, the pulse generating circuit 25 causes the first pulse generating circuit 41
The output pulse of is output. As a result, a sufficiently large rated current I1 is generated in the relay coil 31 as shown in FIG.
Then, the relay contact 32 is surely moved. Also,
At this time, the time measurement circuit 26 starts time measurement.

Next, when the measurement result of the time measuring circuit 26 reaches a predetermined time T0 at time t1, the time measuring circuit 26
Supplies the output pulse switching signal to the pulse generation circuit 25. The pulse generation circuit 25 switches the output pulse from the output pulse of the first pulse generation circuit 41 to the output pulse of the second pulse generation circuit 42 according to the output pulse switching signal.

When the relay coil 31 is driven by the output pulse of the output pulse of the second pulse generating circuit 42 at time t1, the relay coil 31 has a relatively small holding current I2 as shown in FIG. 4C. A certain amount of current flows to hold the relay contact 32 in a predetermined state.

[0013]

However, since the relay device 1 shown in FIG. 1 drives the relay coil 11 using the pulse signal generated by the microcomputer 14, the circuit becomes complicated and expensive. However, since the microcomputer 14 must be constantly driven, there is a problem in that the power consumption cannot be reduced sufficiently.

The relay device 20 shown in FIG. 3 has two pulse generating circuits 41 and 42 and a time value measuring circuit 2.
Since 6 is required, the circuit becomes complicated and expensive, and since the two pulse generation circuits 41 and 42 and the time value measurement circuit 26 must be constantly driven, the power consumption cannot be reduced sufficiently. There were problems such as.

The present invention has been made in view of the above points, and an object thereof is to provide a relay drive device and a relay device which are inexpensive and consume little power.

[0016]

According to a first aspect of the present invention, there is provided a relay drive device for driving a relay by supplying an electric current to the relay coil, which performs self-excited oscillation in cooperation with the relay coil. A self-excited oscillation circuit that intermittently applies voltage to the relay coil, and a predetermined time from when the current is supplied to the relay coil until the self-excited oscillation circuit performs self-excited oscillation,
And a delay circuit for delaying.

According to the present invention, since the self-excited oscillation is delayed by the delay circuit, the current is continuously supplied to the relay coil, so that the relay contact can be reliably driven. After the delay by the delay circuit, self-excited oscillation is performed by the self-excited oscillation circuit and voltage is applied intermittently, so that the state of the relay contact can be maintained with a minimum current. Moreover, since it is self-excited oscillation, unnecessary power is not consumed. Therefore, power consumption can be reduced.

According to a second aspect of the present invention, a self-excited oscillation circuit controls a current supplied to a relay coil, and an electromotive force is induced in response to the excitation of the relay coil to control the switching of the switching element. It is composed of a secondary coil.

According to the present invention, the secondary coil excited by the relay coil feeds back the switching element to control the current in the relay coil, whereby the self-excited oscillation is performed. In this way, self-oscillation can be performed with a simple configuration.

Further, a third aspect of the present invention is characterized in that the delay circuit is provided with a capacitive element for delaying the time from when the switching element is turned on to when the switching element is turned off.

According to the present invention, the delay circuit can be realized with a simple structure by using the capacitive element.

According to a fourth aspect of the present invention, when the voltage applied to the relay coil becomes equal to or higher than the first voltage, the current is supplied to the relay coil and the voltage applied to the relay coil is the first voltage. It is characterized in that it has a drive control circuit for cutting off the supply of current to the relay coil when the voltage becomes equal to or lower than the smaller second voltage.

According to the present invention, when the voltage applied to the relay coil exceeds the first voltage, the current is supplied to the relay coil and the voltage applied to the relay coil is smaller than the first voltage. By providing the drive control circuit that cuts off the supply of current to the relay coil when the voltage becomes equal to or lower than the second voltage, the relay contact can be operated at a predetermined voltage.

A fifth aspect of the present invention is characterized in that it has a unit shape that can be attached to a terminal of a relay device having at least a relay coil and a relay contact therein.

According to the present invention, the drive circuit can be configured separately from the relay. Therefore, the drive circuit can be unitized.

A sixth aspect of the present invention is characterized in that an oscillation frequency of the self-excited oscillation circuit is higher than a frequency including a high frequency range of an audible frequency band.

A seventh aspect of the present invention is characterized in that the oscillation frequency of the self-excited oscillation circuit is 20 kHz or more.

According to the present invention, the oscillation frequency of the self-excited oscillation circuit is set to a frequency higher than the frequency including the high frequency range of the audible frequency band, for example, 20 kHz or more,
The noise of the relay coil and the secondary coil can be reduced.

[0029]

FIG. 5 shows a block diagram of a first embodiment of the present invention.

The relay device 100 of this embodiment comprises a relay section 101 and a relay drive circuit 102. The relay drive circuit 102 includes a transformer 110 and resistors R1 to R.
3, transistor TR, capacitor C1, diode D
It consists of 1.

Further, the relay section 101 includes the relay coil 1
11 and relay contacts 112. The relay coil 111 has one end connected to the input terminal Tin and the other end connected to the transformer 110.

The transformer 110 is composed of a primary coil 121 and a secondary coil 122. The other end of the relay coil 111 is connected to one end of the primary coil 121. The other end of the primary coil 121 is connected to the collector of the transistor TR. The secondary coil 122 of the transformer 110 has one end connected to the base of the transistor TR via a resistor R2 and the other end grounded.

The resistor R1 has one end connected to the input terminal Tin and the other end connected to the base of the transistor TR. The resistor R3 and the capacitor C2 are connected in series and are connected in parallel to the resistor R1.

The diode D1 has an anode connected to the other end of the primary coil 121 and a cathode connected to the relay coil 11
1 is connected to one end. The counter electromotive force generated in the relay coil 111 and the primary coil 121 is absorbed by the diode D1.

The transistor TR and the relay coil 1
11, a transformer 110, resistors R1 and R2 form a self-excited oscillation circuit, and a capacitor C1 and a resistor R3 form a delay circuit.

FIG. 4 shows an operation waveform diagram of the first embodiment of the present invention. 4A is an input voltage Vin applied to the input terminal Tin, and FIG. 4B is a base current I of the transistor TR.
b, FIG. 4 (C) shows the emitter-collector voltage Vce of the transistor TR, FIG. 4 (D) shows the current Ir flowing through the relay coil 111, and FIG. 4 (E) shows the switching state of the relay contact 112.

As shown in FIG. 4A, when the input voltage Vin is applied to the input terminal Tin at time t0, the transistor T
Since the input voltage Vin is applied to the base of R through the resistor R1, the base current Ib flows through the base of the transistor TR as shown in FIG. 4 (B). As a result, the transistor TR is turned on. When the transistor TR is turned on, a current starts to flow in the relay coil 111 and the primary coil 121 of the transformer 110 as shown in FIG.

Next, when the capacitor C1 forming the delay circuit is charged at time t1, the base potential of the transistor TR is lowered and the transistor TR is turned off. At this time, the current flowing through the relay coil 111 corresponds to the collector current Ic of the transistor TR.

The collector current Ic of the transistor TR is
The current amplification factor of the transistor TR is hFE, and the transistor T is
When the base current of R is Ib, it is expressed by Ic = hFE × Ib and increases linearly.

When the collector current Ic reaches a predetermined value,
The induced voltage in the secondary coil 122 decreases, and the transistor T
Since the base current Ib of R decreases, the transistor TR
Turn off.

As shown in FIG. 4D, the transistor TR
The current is supplied to the relay coil 111 for the time T0 until the switch turns off. The relay coil 111 drives and turns on the relay contact 112 by the flowing current during the time T0. At this time, the time T0 is determined by the time constant determined by the capacitor C1 and the resistor R3. By setting the time T0 to be sufficiently large, the relay contact 112 can be reliably turned on.

After that, self-excited oscillation starts.

First, when the transistor TR is turned off at time t1, a forward voltage is generated in the secondary coil 122 by the counter electromotive force generated in the primary coil 121 of the transformer 110. The forward voltage generated in the secondary coil 122 is
It is applied to the base of the transistor TR via the resistor R2. Due to the voltage generated in the secondary coil 122, the transistor TR is turned on again at time t2.

When the transistor TR is turned on, a current flows through the relay coil 111 and the primary coil 121 of the transformer 121. When a current flows through the primary coil 121, a voltage in the opposite direction is generated in the secondary coil 122. When a reverse voltage is generated in the secondary coil 122, the base potential of the transistor TR drops, and the transistor TR turns off again. The transistor TR is repeatedly turned on / off at a predetermined frequency by the voltage generated in the secondary coil 122.

At this time, a current flows through the relay coil 111 according to the duty ratio of the ON period and the OFF period of the transistor TR. The duty ratio is set so that the current flowing through the relay coil 111 is sufficient to hold the relay contact 112 in the ON state.

The oscillation frequency is in the audible frequency band 20.
The frequency is set to a frequency of Hz to 20 kHz or higher, for example, a frequency of 20 kHz or higher. Oscillation frequency is 20 kHz
By the above, the roaring noise in the relay coil 111 and the transformer 110 is not heard, and the noise can be prevented. Note that this frequency is not limited to 20 kHz, and may be any frequency that is inaudible, such as 20 kHz.
The frequency may be slightly lower than z.

In this embodiment, the self-excited oscillation circuit is constructed using the transformer 110, but the secondary coil 122 is used.
May be wound around a yoke of the relay coil 111 and the relay coil 111 may be used as a primary coil.

FIG. 7 is a circuit configuration diagram of the second embodiment of the present invention,
FIG. 8 shows a configuration diagram of the relay section of the second embodiment of the present invention.
5, those parts which are the same as those corresponding parts in FIG. 5 are designated by the same reference numerals, and a description thereof will be omitted.

The relay device 200 of the present embodiment is constructed by removing the transformer 110 and winding the secondary coil 122 around the yoke 211 of the relay section 201.

According to this embodiment, the transformer 110 is not necessary, so that the loss in the transformer 110 can be reduced. Therefore, power consumption can be reduced. Further, since the transformer 110 is not necessary, the number of parts can be reduced and the manufacturing cost can be reduced.

In this embodiment, the secondary coil 122 is wound around the portion of the yoke 211 where the relay coil 111 is not wound, but the secondary coil 122 may be wound on the relay coil 111 in the same manner. It is possible to obtain various actions and effects.

FIG. 9 is a block diagram of a modification of the relay section of the second embodiment of the present invention. 8, those parts which are the same as those corresponding parts in FIG. 8 are designated by the same reference numerals, and a description thereof will be omitted.

The relay section 220 of this modification is constructed by laminating the relay coil 111 and the secondary coil 122 on the iron core 221 and winding them.

According to this embodiment, since the relay coil 111 and the secondary coil 122 are wound around the iron core 221, the relay coil 111 and the secondary coil 122 can be manufactured in the same step, and can be manufactured efficiently.

Eddy current loss can be reduced by using the iron core 221 of the relay coil 111 in which silicon steel plates are laminated or a ferrite core is used. Electric power can be reduced by reducing eddy current loss, and further. Power saving is possible.

In the first and second embodiments, the input voltage V
The operation is compensated when in rises all at once, but the operation voltage is not compensated when the input voltage Vin rises gradually. An embodiment in which the operating voltage is compensated will be described next.

FIG. 10 shows a circuit configuration diagram of the third embodiment of the present invention. 7, those parts which are the same as those corresponding parts in FIG. 7 are designated by the same reference numerals, and a description thereof will be omitted.

The relay device 300 of this embodiment is different from that of the second embodiment in that it has a trigger circuit 301 at the input terminal Tin.

The trigger circuit 301 is composed of a Zener diode Dz, resistors R11 and R12, and a thyristor SCR1. When the input voltage Vin exceeds the operating voltage, the operation of the relay drive circuit is turned on and the input voltage Vin is 0. When [V] is reached, the relay drive circuit is turned off.

FIG. 11 shows an operation waveform diagram of the third embodiment of the present invention. FIG. 11A is an input voltage Vin, FIG. 11B is an anode-cathode voltage of the thyristor SCR1, and FIG.
1 (C) shows the relay coil current, and FIG. 11 (D) shows the state of the relay contact 112.

At time t0, the input voltage Vin gradually rises,
When the operating voltage is reached at time t1, the thyristor SCR1 is turned on as shown in FIG. Thyristor SCR
When 1 is turned on, the emitter of the transistor TR and the other end of the secondary coil 122 are connected to the ground. This turns on the relay drive circuit.

When the relay drive circuit is turned on, a drive current flows through the relay coil 111 as in the first and second embodiments, and the relay contact 112 is turned on at time t2. Time t
Self-excited oscillation starts at time t3 after a lapse of a predetermined time T0 from 1.

When the input voltage Vin is cut off at time t4 as shown in FIG. 11A, the thyristor SCR1 is turned off as shown in FIG. 11B. When the thyristor SCR1 turns off, the relay drive circuit turns off. As shown in FIG. 11D, the relay drive circuit is turned off, and the relay contact 112 is turned off at time t5 when the recovery time T1 has elapsed.

According to this embodiment, the relay contact 112 can be reliably turned on with a predetermined voltage even when the input voltage Vin gradually rises.

In the third embodiment, the open circuit voltage is not compensated when the input voltage Vin gradually decreases. Therefore, an embodiment in which the open circuit voltage can be compensated even when the input voltage Vin gradually decreases will be described.

FIG. 12 shows a circuit configuration diagram of the fourth embodiment of the present invention. 10, those parts which are the same as those corresponding parts in FIG. 10 are designated by the same reference numerals, and a description thereof will be omitted.

In this embodiment, the configuration of the trigger circuit 401 is the third.
It differs from the embodiment. The trigger circuit 401 of this embodiment is
In addition to Zener diode Dz, resistors R11 and R12, and thyristor SCR1, Zener diode Dz2 and resistor R21
.About.R26, a transistor TR2, and a thyristor SCR2 are added.

FIG. 13 shows an operation waveform diagram of the fourth embodiment of this embodiment. FIG. 13 (A) shows the input voltage Vin, and FIG. 13 (B).
13C shows the voltage between the anode and cathode of the thyristor SCR1, FIG. 13C shows the voltage between the anode and cathode of the thyristor SCR2, FIG. 13D shows the current of the relay coil 111, and FIG. 13E shows the state of the relay contact 112. .

At time t0, the input voltage Vin begins to drop, and when it reaches the open circuit voltage at time t1, the thyristor SCR2 turns on. When the thyristor SCR2 is turned on, the electric charge stored in the capacitor C2 is discharged. By discharging the capacitor C2, the thyristor SCR1 is turned off.

When the thyristor SCR1 is turned off at the time t1, the self-excited oscillation operation of the relay drive circuit is stopped. After the self-excited oscillation operation of the relay drive circuit is stopped at time t1, the relay contact 112 is opened as shown in FIG. 13 (E) at time t2 when a predetermined recovery time has elapsed.

According to this embodiment, the relay contact 112 can be opened with a predetermined open voltage even when the input voltage Vin gradually decreases.

Next, an application example of the relay device of the above embodiment will be described.

For example, in the first embodiment, the secondary coil 12
2 is composed of a transformer 110, which is separate from the relay coil 111, and may be connected to the relay coil 111 by wiring. Therefore, the relay drive circuit 102 can be configured as a unit separate from the relay unit 102.
By unitizing the relay drive circuit 102, a general relay device including a relay coil 111 and a relay contact 112 can be used.

FIG. 14 shows a perspective view of an application example of the present invention.

The power-saving relay device 500 of the application example comprises a relay device 501 and a relay drive unit 502. The relay drive unit 502 includes a circuit board 511,
It is composed of a socket case 512 and a socket cover 513.

The relay drive circuit 102 shown in FIG. 5 is mounted on the circuit board 511. In addition, the circuit board 511
A relay connection terminal 521 and an external terminal 522 are mounted on the. The relay connection terminal 521 is provided on the circuit board 511.
It is provided at a position corresponding to the external terminal 531 of the relay device 501 on the upper surface side, and the external terminal 531 can be attached and detached. The external terminal 522 is provided on the lower surface side of the circuit board 511 at a position corresponding to the external terminal 531 of the relay device 501, and can be soldered to an external circuit board or the like.

The circuit board 511 is a socket case 512.
Is stored in. The socket case 512 has a hole 541 formed at a position corresponding to the external terminal 522 on the bottom surface. When the circuit board 511 is housed in the socket case 512, the external terminal 522 extends through the hole 541 to the outside.

The socket cover 513 covers the upper open surface of the socket case 512. Socket cover 513
A hole portion 551 is formed at a position corresponding to the relay connection terminal 521 provided on the upper surface of the circuit board 511. The external terminal 531 of the relay device 501 has a hole 551.
Through to the relay connection terminal 521 of the circuit board 511.

By attaching the external terminal 531 of the relay device 501 to the relay connection terminal 521 of the relay drive unit 502 and connecting the external terminal 522 of the relay drive unit 502 to the external circuit board, the general relay device 50
1, a relay drive circuit 102 as shown in FIG. 5 can be added. Therefore, the general relay device 501 can be pulse-driven by self-excited oscillation, and power can be saved.

Further, the relay drive circuit 102 may be built in the relay device.

FIG. 15 shows an exploded perspective view of another application example.
5, those parts which are the same as those corresponding parts in FIG. 5 are designated by the same reference numerals, and a description thereof will be omitted.

The relay device 600 of this application example is based on the base 6
01, a case 602, a relay unit 101, and a relay drive unit 603. The relay unit 101 and the relay drive unit 603 are mounted on the base 601. The relay drive unit 603 includes a relay drive circuit 1
02 is installed. The relay drive circuit 102 is connected to the relay coil 101 mounted on the base 601, and pulse-drives the relay coil 101 as in the first embodiment. The case 602 is attached to the base 601 and houses the relay unit 101 and the relay drive unit 603.

By incorporating the relay drive circuit 102 in the case 602, a power-saving type relay device can be constructed by itself. Further, since the external appearance is similar to that of a normal relay device, it can be used in the same manner as a normal relay device.

[0084]

As described above, according to the present invention, since the self-excited oscillation is delayed by the delay circuit, the current is continuously supplied to the relay coil, so that the relay contact can be reliably driven. After the delay circuit delays, the self-excited oscillation circuit performs self-excited oscillation and the voltage is applied intermittently, so the state of the relay contact can be maintained with a minimum current, and it is self-excited oscillation. Therefore, unnecessary power is not consumed, and power consumption can be reduced.

According to the present invention, the secondary coil excited by the relay coil feeds feedback to the switching element to control the current in the relay coil, whereby the self-excited oscillation is performed. In this way, self-oscillation can be performed with a simple configuration.

According to the present invention, the delay circuit can be realized with a simple structure by using the capacitive element.

According to the present invention, when the voltage applied to the relay coil becomes equal to or higher than the first voltage, the current is supplied to the relay coil and the voltage applied to the relay coil is smaller than the first voltage. By providing the drive control circuit that cuts off the supply of current to the relay coil when the voltage becomes equal to or lower than the second voltage, the relay contact can be operated at a predetermined voltage.

According to the present invention, the core of the relay coil can be shared by winding the secondary coil around the core around which the relay coil is wound or by winding the secondary coil over the relay coil. Can be realized with a simple configuration.

According to the present invention, the secondary coil is the secondary coil of the transformer in which the primary coil is connected to the relay coil in series, and can be mounted on at least the terminal of the relay device having the relay coil and the relay contact built therein. By doing so, it can be unitized.

According to the present invention, the oscillation frequency of the self-excited oscillation circuit is set to a frequency higher than the frequency including the high frequency range of the audible frequency band, for example, 20 kHz or more,
The noise of the relay coil and the secondary coil can be reduced.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an example of a conventional relay device.

FIG. 2 is an operation waveform diagram of an example of a conventional relay device.

FIG. 3 is a block configuration diagram of another example of a conventional relay device.

FIG. 4 is an operation waveform diagram of another example of a conventional relay device.

FIG. 5 is a circuit configuration diagram of a first embodiment of the present invention.

FIG. 6 is an operation waveform diagram of the first embodiment of the present invention.

FIG. 7 is a circuit configuration diagram of a second embodiment of the present invention.

FIG. 8 is a configuration diagram of a relay unit according to a second embodiment of the present invention.

FIG. 9 is a configuration diagram of a modification of the relay unit according to the second embodiment of the present invention.

FIG. 10 is a circuit configuration diagram of a third embodiment of the present invention.

FIG. 11 is an operation waveform diagram of the third embodiment of the present invention.

FIG. 12 is a circuit configuration diagram of a fourth embodiment of the present invention.

FIG. 13 is an operation waveform diagram of the fourth embodiment of the present invention.

FIG. 14 is a perspective view of an application example of the present invention.

FIG. 15 is a perspective view of another application example of the present invention.

[Explanation of symbols]

100, 200, 300, 400: Coil device 101: Relay part, 102: Relay drive circuit 110: Transformer, 111: Relay coil, 112: Relay contact 121: Primary coil, 122: Secondary coil Tin: Input terminal, TR : Transistor, D1: Diode, R1-R3: Resistor C1: Capacitor

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5G057 AA01 AA02 AA09 BB01 BC04                       BD04 KK01 RR01 RS01 RS07                       RT01                 5J055 AX12 AX44 BX16 CX13 CX21                       DX04 EY01 EY07 EY10 EY12                       EY13 EY26 EZ28 EZ42 EZ50                       GX01 GX04 GX09

Claims (8)

[Claims] 1. A relay drive device for driving a relay by supplying a current to a relay coil, wherein self-excited oscillation is performed in cooperation with the relay coil, and a voltage is intermittently applied to the relay coil. A relay drive device comprising: a self-excited oscillation circuit; and a delay circuit that delays for a predetermined time from the start of current supply to the relay coil until the self-excited oscillation circuit performs self-excited oscillation. . 2. The self-excited oscillating circuit includes a switching element that controls a current supplied to the relay coil, and a secondary coil that induces an electromotive force according to the excitation of the relay coil and controls the switching of the switching element. The relay drive device according to claim 1, further comprising: 3. The relay drive device according to claim 2, wherein the delay circuit has a capacitive element that delays a time from when the switching element is turned on to when the switching element is turned off. 4. The first voltage is applied to the relay coil.
Current is supplied to the relay coil when the voltage becomes equal to or higher than the voltage, and when the voltage applied to the relay coil becomes equal to or lower than a second voltage that is smaller than the first voltage, The relay drive device according to any one of claims 1 to 3, further comprising a drive control circuit that disconnects supply of current. 5. The relay drive device according to claim 1, wherein the relay drive device has a unit shape that can be attached to a terminal of a relay device including at least a relay coil and a relay contact. 6. The relay drive device according to claim 1, wherein an oscillation frequency of the self-excited oscillation circuit is higher than a frequency including a high frequency range of an audible frequency band. 7. The oscillation frequency of the self-excited oscillator circuit is 1
7. The relay drive device according to claim 1, wherein the relay drive device has a frequency of 5 kHz or higher. 8. A relay device comprising the relay drive device according to claim 1. Description: