KR20140073800A - Circuit for elctronic relay - Google Patents

Circuit for elctronic relay Download PDF

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Publication number
KR20140073800A
KR20140073800A KR1020120141677A KR20120141677A KR20140073800A KR 20140073800 A KR20140073800 A KR 20140073800A KR 1020120141677 A KR1020120141677 A KR 1020120141677A KR 20120141677 A KR20120141677 A KR 20120141677A KR 20140073800 A KR20140073800 A KR 20140073800A
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KR
South Korea
Prior art keywords
mosfet
transistor
signal
relay
capacitor
Prior art date
Application number
KR1020120141677A
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Korean (ko)
Inventor
이진우
Original Assignee
현대모비스 주식회사
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Publication date
Application filed by 현대모비스 주식회사 filed Critical 현대모비스 주식회사
Priority to KR1020120141677A priority Critical patent/KR20140073800A/en
Publication of KR20140073800A publication Critical patent/KR20140073800A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
    • H01H47/02—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for modifying the operation of the relay
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
    • H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
    • H03K17/08104—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit in field-effect transistor switches

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  • Electronic Switches (AREA)

Abstract

The present invention relates to a circuit for an electronic relay, comprising: an amplifying section for amplifying an input control signal; a charging section for charging and outputting a driving signal for driving the MOSFET in response to an output signal from the amplifying section; And a relay including a first MOSFET and a second MOSFET that are off-controlled to supply power to the load, wherein the first MOSFET and the second MOSFET have their drain terminals connected to each other. According to the present invention, by making the power source applied to the source terminal of the MOSFET when the relay circuit is turned on and off, it is possible to prevent the MOSFET from being damaged by sudden overcurrent application.

Description

{CIRCUIT FOR ELCTRONIC RELAY}

The present invention relates to a circuit for an electronic relay, and more particularly, to a circuit for an electronic relay, in which a surge voltage generated when a relay turns on is prevented in a MOSFET (Metal Oxide Silicon Field Effect Transistor) To circuits for electronic relays to prevent failures.

In general, a relay refers to a device having a function of controlling on / off of an electric circuit by using a predetermined electrical signal.

Relays are classified into mechanical relays and electronic relays according to their operating principles. Mechanical relays use electromagnets to control the on / off state of the electric circuit by connecting the magnetic contacts to the electrodes when current flows through the electromagnets. to be.

The electronic relay is a relay (contactless) relay in which an electrical contact is removed by using a semiconductor element in an electrical circuit opening and closing part of a relay. The relay is an output side having a high load opening / A high load current flows to the output side to control on / off of the electric circuit.

In addition to being able to control the output signal of a high load even if the input signal is very small, the electronic relay does not have a mechanical working part and therefore has a long life and reliability and is not influenced by impact, Widely used.

1 is a diagram showing a connection circuit of a switching element of a conventional circuit for an electronic relay.

In general, MOSFETs (Metal Oxide Silicon Field Effect Transistors) 1 and 2 in a circuit for an electronic relay for a vehicle are connected to each other at their source terminals as shown in FIG. 1, and the drain terminal is connected to a pre- Pre-charge).

In order to turn on each of the MOSFETs 1 and 2 while the MOSFETs 1 and 2 are off, a larger voltage is applied to the gate terminal The voltage of 12V, which is the voltage of the vehicle battery, is applied to the gate terminal.

When the MOSFETs 1 and 2 are turned on, the drain terminal voltage is applied to the source terminal of each of the MOSFETs 1 and 2, and the source terminal 12V is maintained. Therefore, the MOSFETs 1 and 2 are kept in the on state It is necessary to apply a larger voltage to the gate terminal in contrast to the voltage at the source terminal.

Therefore, conventionally, a power source that is boosted from 12V to 24V was applied to the gate terminal of each of the MOSFETs 1 and 2 to keep the MOSFETs 1 and 2 in the ON state.

That is, in order to increase the voltage applied to the gate terminal with respect to the voltage applied to the source terminals of the MOSFETs 1 and 2 in the related art, two boosting processes are required.

In order to maintain the MOSFETs 1 and 2 in the ON state, in the process of applying a 24 V boosted power supply to the gate terminals of the MOSFETs 1 and 2, the voltage at the drain terminal is immediately applied to the source terminal, 12V is momentarily applied to the gate terminal, but the gate terminal is applied from 12V to 24V with a time delay, and the MOSFETs 1 and 2 can be turned off at the moment when both the source terminal and the gate terminal are applied with 12V.

In addition, since the respective MOSFETs 1 and 2 are turned on, the power source flowing from the drain terminal to the source terminal instantaneously rises from 0 V to 12 V, which causes a problem that the MOSFETs 1 and 2 fail due to the overcurrent.

A prior art related to the present invention is Korean Patent Laid-Open Publication No. 10-1999-0065675 (published on Aug. 5, 1999, entitled "Electronic Switch Circuit").

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a MOSFET (Metal Oxide Silicon Field Effect Transistor) having source terminals connected to each other to prevent a surge voltage generated at relay turn- The present invention also provides a circuit for an electronic relay for preventing an overvoltage.

According to an aspect of the present invention, there is provided an electronic relay circuit comprising: an amplifier for amplifying an input control signal; A charging unit charging and outputting a driving signal for driving the MOSFET in response to an output signal from the amplifying unit; And a relay including a first MOSFET (Metal Oxide Silicon Field Effect Transistor) and a second MOSFET that are turned on and off in response to a drive signal from the charging unit to supply power to the load, wherein the first MOSFET and the second MOSFET And each drain terminal is connected to each other.

In the present invention, the source terminals of the first MOSFET and the second MOSFET are pre-charged by an input power source.

In the present invention, the amplifying unit includes a first transistor that is pulled down in response to the input control signal provided from an MCU (Micro Controller Unit), and the amplifying unit amplifies the input control signal when the first transistor is turned on And outputs the amplified signal.

In the present invention, the charging unit includes a second transistor and a third transistor that are turned on and off differently in response to an output signal from the amplifying unit; And a capacitor for storing the driving signal for driving the MOSFET in accordance with an on / off state of the second transistor and the third transistor.

The second transistor charges the capacitor by pulling up the output terminal to the capacitor in response to an output signal from the amplifier, and the third transistor is responsive to an output signal from the amplifier, And the capacitor is discharged by pulling down the output terminal of the capacitor.

According to the present invention, by making the power source applied to the source terminal of the MOSFET when the relay circuit is turned on and off, it is possible to prevent the MOSFET from being damaged by sudden overcurrent application.

In addition, the present invention reduces the step-up of the voltage applied to the MOSFET for turning on the relay circuit to one time, thereby preventing instantaneous turn-off of the relay circuit which may occur due to the delay of the step-

1 is a diagram showing a connection circuit of a switching element of a conventional circuit for an electronic relay.
2 is a diagram showing a connection circuit of a switching element of a circuit for an electronic relay according to an embodiment of the present invention.
3 is a circuit diagram of an electronic relay according to an embodiment of the present invention.

Hereinafter, a circuit for an electronic relay according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

2 is a diagram showing a connection circuit of a switching element of a circuit for an electronic relay according to an embodiment of the present invention.

3 is a circuit diagram of an electronic relay according to an embodiment of the present invention.

2 to 3, the electronic relay circuit includes an amplification unit 10, a charging unit 20, and a relay unit 30.

3, R represents a resistor, C represents a capacitor, D represents a diode, and V batt represents a battery voltage of the vehicle.

The amplifying unit 10 amplifies the input control signal to supply a signal required for ON / OFF control of the relay unit 30, which will be described later, and supplies the amplified input control signal to a charging unit 20 to be described later. Specifically, a signal of 0V to 12V is required to turn on / off the relay unit 30. Since the output of the logic level of the MCU (Micro Controller Unit) (not shown) is only a signal of 0V to 3.3V, 10 amplifies the input control signal to 12V.

To this end, the amplifying unit 10 includes a first transistor 12 pulled down in response to a PWM-type control signal provided from the MCU, and an input control signal from the MCU is enabled so that the first transistor 12 And outputs a signal amplified by 12 V. When the input control signal is disabled, a signal of 0 V is output when the first transistor 12 is turned off.

The charging unit 20 charges the MOSFET driving signal of the relay unit 30, which will be described later, in response to the output signal from the amplifying unit 10, and outputs the charging signal. The second transistor 22 and the third transistor 24 are turned on and off differently in response to the output signal of the amplifier unit 10 and the second transistor 22 and the third transistor 24 are turned on And a capacitor 26 for storing a driving signal for driving the MOSS according to the OFF state.

Specifically, as shown in FIG. 3, each of the transistors 22 and 24 is set to be a different type so that the transistors 22 and 24 are turned on and off differently according to signals applied to the base stage. Therefore, in the present embodiment, the second transistor 22 is a PNP type transistor and the third transistor 24 is an NPN type transistor. However, the present invention is not limited thereto.

The collector terminals of the transistors 22 and 24 are connected to each other and the amplifier unit 10 is connected to the base ends of the transistors 22 and 24 so that the output signal of the amplifier unit 10 Each of the transistors 22 and 24 is turned on and off by the output signal of the amplifying part 10 since it is applied to the base end of each of the transistors 22 and 24.

The second transistor 22 pulls up the output terminal to the capacitor 26 in response to the output signal from the amplifier 10 to charge the capacitor 26 and the third transistor 24 charges the amplifier 26, And discharges the capacitor 26 by pulling down the output terminal to the capacitor 26 in response to the output signal from the capacitor 26.

3, when the high signal is inputted to the base ends of the transistors 22 and 24 in response to the output signal from the amplifying unit 10, the second transistor 22 is turned on And the third transistor 24 is turned on. Since the third transistor 24 is turned on, the power of the capacitor 26 connected to the collector terminal of the third NPN transistor 24 is supplied to the third transistor 24, so that the capacitor 26 is discharged.

On the other hand, when a low signal is inputted to the base end of each of the transistors 22 and 24 in response to the output signal from the amplifier 10, the second transistor 22 is turned on and the third transistor 24 is turned off. Since the second transistor 22 is turned on, the capacitor 26 is charged because the power is supplied to the capacitor 26 connected to the collector terminal of the PNP type second transistor 22.

That is, in this embodiment, the second transistor 22 and the third transistor 24 are controlled to be turned on and off differently in response to the output signal of the above-described amplifier 10, , And the capacitor 26 is charged or discharged according to the OFF state.

The relay unit 30 includes a first MOSFET 32 and a second MOSFET 34 whose drain terminals are connected to each other and are turned on and off according to the first MOSFET 32 and the second MOSFET 34, (Not shown) is turned on or off. In particular, the load in this embodiment is a motor as an example.

Specifically, the drain terminals of the first MOSFET 32 and the second MOSFET 34 are connected to each other, and the gate ends of the MOSFETs 32 and 34 are also connected to each other and driven by the same signal. In this embodiment, the source terminals of the MOSFETs 32 and 24 are pre-charged to 12V, which is the battery voltage of the vehicle.

Therefore, in order to supply power to the motor through the relay unit 30, a larger signal must be applied to the gate terminal in comparison with the voltage at the source terminal of each MOSFET 32 and 34, and the capacitor of the charging unit 20 The relay unit 30 is turned on and the capacitor 26 is discharged and the driving signal is supplied to the gate terminals of the MOSFETs 32 and 34. [ The PWM control is performed in such a manner that the relay unit 30 is turned off.

That is, when a drive signal is applied to the gate of each of the MOSFETs 32 and 34 to the capacitor 26, a signal applied to the drain terminal of the MOSFET 32 and a signal applied to the drain of the capacitor 26, The drain terminal is connected to the gate terminal of each of the MOSFETs 32 and 34 when the relay 26 is turned on and the capacitor 26 is discharged and a driving signal is not applied to the gate terminal of each of the MOSFETs 32 and 34. [ The relay unit 30 is turned off.

Since the present embodiment receives a PWM type input control signal from the MCU, the on and off states of the following elements are controlled in PWM form. That is, the signal supplied to the motor is controlled in such a manner that the ON / OFF ratio of the relay unit 30 is changed by the duty ratio of the high signal and the low signal.

The power source applied to the source terminal of each of the MOSFETs 32 and 34 is maintained in a precharged state in the same manner when the relay unit 30 is turned on in the off state, 32 and 34 are boosted, the circuit configuration for boosting the power supply applied to the source terminals of the MOSFETs 32 and 34 can be omitted.

According to the present embodiment, since the voltages applied to the source terminals of the MOSFETs 32 and 34 are maintained the same, a surge voltage generated when the source terminals of the MOSFETs 1 and 2 are stepped up is generated I never do that.

The operation of the electronic relay circuit according to an embodiment of the present invention having the above-described structure will now be described.

The relay unit 30 of the present embodiment includes a first MOSFET 12 and a second MOSFET 14 whose drain terminals are connected to each other and are connected to surges generated by the boosting at the source terminals of the MOSFETs 12, The source terminals of the MOSFETs 12 and 14 are precharged to 12V, which is the battery voltage of the vehicle.

Therefore, when the relay section 30 is in the OFF state, the source terminal and the gate terminal of each of the MOSFETs 12 and 14 are applied with a signal of 12V, and when the relay section 30 is in the ON state, The relay terminal 30 is turned on by allowing 24V to be applied to the gate terminal to open the path of power supply to the motor.

The amplification unit 10 amplifies the input control signal and supplies a signal required for driving the MOSFET of the relay unit 30 to the charging unit 20. Since the second transistor 22 and the third transistor 24 of the charging unit 20 are set to different types, they are turned on and off differently according to the output of the amplifying unit 10. [

The drive signal for driving the MOSFET is turned on and off by the second transistor 22 and the third transistor 24 in response to the output signal of the amplifier 10 and the capacitor 26 is charged or discharged. The gate terminal is stepped up to 24V when the driving signal stored in the gate of the MOSFET 12 or 14 is supplied to the gate terminal of each MOSFET 12 or 14 so that the relay unit 30 is turned on.

According to the present embodiment, by keeping the power supply applied to the source terminals of the respective MOSFETs 32, 34 when the relay circuit is turned on and off the same as precharging, the respective MOSFETs 32, Can be prevented from being damaged.

In addition, the present embodiment reduces the step-up of the voltage applied to each MOSFET 32, 34 for turning on the relay circuit to one time, thereby preventing instantaneous turn-off of the relay circuit which may occur due to delay of step- can do.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Accordingly, the true scope of the present invention should be determined by the following claims.

10: amplification part 12: first transistor
20: charger 22: second transistor
24: third transistor 26: capacitor
30: amplifying unit 32: first MOSFET
34: Second MOSFET

Claims (5)

An amplifier for amplifying an input control signal;
A charging unit charging and outputting a driving signal for driving the MOSFET in response to an output signal from the amplifying unit; And
And a relay unit including a first MOSFET (Metal Oxide Silicon Field Effect Transistor) and a second MOSFET that are turned on and off in response to a driving signal from the charging unit to supply power to the load,
Wherein the first MOSFET and the second MOSFET have their respective drain terminals connected to each other.
The method according to claim 1,
Wherein the source terminal of the first MOSFET and the second MOSFET are pre-charged by an input power source.
The method according to claim 1,
Wherein the amplifying unit includes a first transistor pulled down in response to the input control signal provided from a micro controller unit (MCU)
Wherein the amplifying unit outputs the amplified signal when the input control signal is enabled and the first transistor is turned on.
The method according to claim 1,
A second transistor and a third transistor that are turned on and off differently in response to an output signal from the amplifier; And
A capacitor for storing the driving signal for driving the MOSFET in accordance with on / off of the second transistor and the third transistor;
And an output terminal connected to the output terminal.
5. The method of claim 4,
And the second transistor charges the capacitor by pulling up the output terminal to the capacitor in response to an output signal from the amplifier,
And the third transistor pulls down the output terminal to the capacitor in response to an output signal from the amplifier to discharge the capacitor.
KR1020120141677A 2012-12-07 2012-12-07 Circuit for elctronic relay KR20140073800A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020120141677A KR20140073800A (en) 2012-12-07 2012-12-07 Circuit for elctronic relay

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020120141677A KR20140073800A (en) 2012-12-07 2012-12-07 Circuit for elctronic relay

Publications (1)

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KR20140073800A true KR20140073800A (en) 2014-06-17

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10756729B2 (en) 2018-07-26 2020-08-25 Hyundai Mobis Co., Ltd. Electronic relay device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10756729B2 (en) 2018-07-26 2020-08-25 Hyundai Mobis Co., Ltd. Electronic relay device

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