CN211654701U

CN211654701U - Relay drive circuit and electromagnetic heating equipment

Info

Publication number: CN211654701U
Application number: CN202020784651.5U
Authority: CN
Inventors: 李世勤; 赵礼荣
Original assignee: Zhejiang Shaoxing Supor Domestic Electrical Appliance Co Ltd
Current assignee: Zhejiang Shaoxing Supor Domestic Electrical Appliance Co Ltd
Priority date: 2020-05-13
Filing date: 2020-05-13
Publication date: 2020-10-09
Anticipated expiration: 2030-05-13

Abstract

The utility model provides a relay drive circuit and electromagnetic heating equipment, this drive circuit includes: the charging and discharging circuit comprises a switching circuit, a charging and discharging circuit and a control circuit; the charging and discharging circuit at least comprises a first capacitor, and the first capacitor is connected with the output end of the control circuit so as to receive a level signal of the control circuit; the input end of the switch circuit is connected with the charge-discharge circuit, and the output end of the switch circuit is connected with the coil of the relay so as to be switched on or off under the control of the charge-discharge circuit. The drive circuit controls the on-off of the switch circuit through the control circuit and the charging and discharging circuit, and the safety of the electromagnetic heating equipment is improved.

Description

Relay drive circuit and electromagnetic heating equipment

Technical Field

The utility model relates to a circuit technology especially relates to a relay drive circuit and electromagnetic heating equipment.

Background

Electromagnetic heating equipment, such as electromagnetism stove or electromagnetism kitchen, is the device that utilizes electromagnetic induction phenomenon to convert electric energy into heat energy, along with the progress of technique, the continuous improvement of components and parts quality, electromagnetic heating equipment's application is also more and more popularized.

In order to improve the safety of the electromagnetic heating equipment, a relay is arranged in a main loop of part of the electromagnetic heating equipment, and the on-off of the main loop is controlled by the on-off of the relay. In the existing electromagnetic heating device, a relay driving circuit generally comprises a triode, a control chip outputs high level to the triode, the triode is in saturation conduction to electrify a relay coil to generate a magnetic field, and a contact acts to pull in under the action of the magnetic field, so that a main circuit is electrified and conducted. After the electromagnetic heating equipment is used, the control chip continuously outputs low level, the triode is cut off to enable the coil of the relay to be powered off, the contact is disconnected, and therefore the main loop is disconnected.

The problem that above-mentioned scheme exists is that if control chip breaks down and continuously outputs high level, then the triode is in saturation conducting state always, leads to the relay contact to be in the actuation state always, and this just makes the major loop be in the power-on conducting state all the time to produce the potential safety hazard.

SUMMERY OF THE UTILITY MODEL

The utility model provides a relay drive circuit and electromagnetic heating equipment has improved electromagnetic heating equipment's security.

In a first aspect, the present application provides a relay drive circuit, comprising: the charging and discharging circuit comprises a switching circuit, a charging and discharging circuit and a control circuit;

the charging and discharging circuit at least comprises a first capacitor, and the first capacitor is connected with the output end of the control circuit so as to receive a level signal of the control circuit;

the input end of the switch circuit is connected with the charge-discharge circuit, and the output end of the switch circuit is connected with the coil of the relay so as to be switched on or off under the control of the charge-discharge circuit.

The drive circuit utilizes the coupling characteristic of the first capacitor in the charge-discharge circuit, and can normally control the on or off of the switch circuit when the control circuit outputs a rectangular wave drive signal or a continuous low-level signal, so that the on or off of the relay is controlled to ensure the normal work of the electromagnetic heating equipment. When the control circuit is in fault and continuously outputs a high-level signal, the first capacitor is filled and is opened, so that the switching circuit can be cut off, the contact of the relay is disconnected, the main loop of the electromagnetic heating equipment is prevented from being continuously electrified in unnecessary time, and the safety is improved.

In one possible implementation, the charge and discharge circuit further includes a discharge loop;

the first end of the first capacitor is connected with the input end of the switch circuit, and the second end of the first capacitor is connected with the output end of the control circuit through the first resistor;

the discharging loop is respectively connected with the first end of the first capacitor and the input end of the switch circuit, and the discharging loop is grounded.

The first capacitor in the driving circuit discharges through the discharging loop, so that the switching circuit can be kept on when the control circuit outputs the low level state of the rectangular wave signal, and the switching circuit is switched off when the control circuit continuously outputs the low level, so that the relay is switched on or switched off, and the normal work of the relay is ensured.

In one possible implementation, the charging and discharging circuit further includes a second capacitor;

the first end of the second capacitor is connected with the first end of the first capacitor and the input end of the switch circuit respectively, and the second end of the second capacitor is grounded.

The charging and discharging of the first capacitor and the second capacitor in the charging and discharging circuit ensure that when the control circuit outputs rectangular wave signals, the voltage output by the charging and discharging circuit can maintain the switch circuit to be switched on, so that the relay is controlled to be switched on, and the stability of the driving circuit is ensured.

In one possible implementation, the discharge circuit includes a first diode;

the cathode of the first diode is connected with the first end of the first capacitor and the input end of the switch circuit respectively, and the anode of the first diode is grounded.

In one possible implementation, the discharge circuit includes a second resistor;

the first end of the second resistor is connected with the first end of the first capacitor and the input end of the switch circuit respectively, and the second end of the second resistor is grounded.

In one possible implementation, the switching circuit includes a first switching tube;

the first end of the first switch tube is connected with the first end of the coil of the relay; the second end of the first switching tube is grounded through a third resistor; the third end of the first switch tube is connected with the first end of the first capacitor through a fourth resistor;

and the second end of the coil of the relay is connected with a direct current power supply.

First switch tube among the switch circuit switches on or cuts off under the signal of control circuit output, the control of charge-discharge circuit to realized the control to switching on or breaking off of relay contact, simultaneously, because the coupling characteristic of first electric capacity, can guarantee when control circuit continuously outputs the high level, first electric capacity electric quantity is full of and opens a way, first switch tube ends, make the relay disconnection, the security of major loop has been guaranteed, this drive circuit simple structure, easily realization.

In one possible implementation, the switching circuit includes a second switching tube and a third switching tube;

the first end of the second switching tube is connected with the direct-current power supply through a fifth resistor and a sixth resistor, the second end of the second switching tube is grounded, and the third end of the second switching tube is connected with the first end of the first capacitor through a seventh resistor;

the first end of the third switching tube is connected with the direct-current power supply, the second end of the third switching tube is connected with the second end of the coil of the relay, and the third end of the third switching tube is respectively connected with the fifth resistor and the sixth resistor;

and the first end of the coil of the relay is grounded through an eighth resistor.

The switching circuit comprises two switching tubes, so that the power consumption is lower, and the switching circuit is easier to start.

In one possible implementation, the driving circuit further includes a second diode D2;

a second diode D2 is connected in parallel with the coil of the relay to provide a discharge circuit to avoid damage to the switching tube in the switching circuit.

In one possible implementation, the driving circuit further includes: a fault detection circuit;

and the fault detection circuit is respectively connected with the coil of the relay and the input end of the control circuit.

In one possible implementation, the fault detection circuit includes a ninth resistor and a third capacitor C3;

a first end of the ninth resistor is connected with a first end of a coil of the relay, and a second end of the ninth resistor is respectively connected with a first end of the third capacitor C3 and an input end of the control circuit;

the second terminal of the third capacitor C3 is connected to ground.

The abnormal voltage signal is detected by the fault detection circuit when the relay and the relay drive circuit are in fault, so that the control circuit 40 can close the drive signal output to cut off the main loop, and the safety of the electromagnetic heating equipment is further improved.

In a second aspect, the present application provides an electromagnetic heating apparatus comprising a relay and a relay drive circuit; the relay drive circuit is the relay drive circuit according to any one of the first aspect.

The utility model provides a relay drive circuit and electromagnetic heating equipment utilizes the coupling characteristic of first electric capacity among the charging and discharging circuit, when control circuit output rectangular wave drive signal or the low level signal that lasts, can normally control switching circuit switch on or turn-off to control relay switches on or turn-off guarantees electromagnetic heating equipment's normal work. When the control circuit is in fault and continuously outputs a high-level signal, the first capacitor is in an open circuit due to full charge of electricity, the switch circuit can be disconnected, so that the contact of the relay is disconnected, the main loop of the electromagnetic heating equipment is prevented from being continuously electrified in unnecessary time, and the safety is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a circuit diagram of an electromagnetic heating apparatus provided by the present invention;

fig. 2 is a first schematic diagram of a relay driving circuit provided by the present invention;

fig. 3 is a second schematic diagram of a relay driving circuit provided by the present invention;

fig. 4 is a third schematic diagram of a relay driving circuit provided by the present invention;

fig. 5 is a fourth schematic diagram of a relay driving circuit provided by the present invention;

fig. 6 is a fifth schematic diagram of a relay driving circuit provided by the present invention;

fig. 7 is a sixth schematic diagram of a relay driving circuit provided by the present invention;

fig. 8 is a seventh schematic diagram of a relay driving circuit provided by the present invention;

fig. 9 is an eighth schematic diagram of a relay driving circuit provided by the present invention;

fig. 10 is a schematic diagram nine of a relay driving circuit provided by the present invention;

fig. 11 is a schematic diagram ten of a relay driving circuit provided by the present invention;

fig. 12 is an eleventh schematic diagram of a relay driving circuit provided by the present invention;

fig. 13 is a twelve schematic diagram of a relay driving circuit provided by the present invention;

fig. 14 is a thirteenth schematic diagram of a relay driving circuit provided by the present invention;

fig. 15 is a fourteenth schematic diagram of a relay driving circuit provided by the present invention.

Description of reference numerals:

10-a relay; 20-a switching circuit; 30-a charge-discharge circuit; 40-a control circuit; 31-a discharge circuit; 50-fault detection circuit.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In order to improve the safety of the electromagnetic heating equipment, a relay is arranged in a main loop of part of the electromagnetic heating equipment, and the on-off of the main loop is controlled by the on-off of the relay. For example, as shown in fig. 1, when the contacts of the relay 10 in the main circuit are closed, the main circuit is turned on, when the contacts of the relay 10 are opened, the main circuit is opened, and when the contacts of the relay 10 are closed or opened, the contacts are controlled by a control circuit, such as a Micro Controller Unit (MCU) or a control chip, through a driving circuit.

In the prior art, a driving circuit of the relay 10 generally includes a triode, when an electromagnetic heating device is used, a control chip outputs a high-level signal to the triode, the triode is saturated and conducted to electrify a coil of the relay 10 to generate a magnetic field, and a contact acts and attracts under the action of the magnetic field, so that the main circuit is electrified and conducted. When the electromagnetic heating equipment is used, the control chip outputs low level, the triode is cut off to enable the coil of the relay 10 to be powered off, the contact is disconnected, and therefore the main loop is disconnected.

The problem that above-mentioned scheme exists is that if control chip breaks down and continuously outputs high level, then the triode is in saturation conducting state all the time, leads to the contact of relay 10 to be in the actuation state all the time, and this just makes the major loop be in power-on conducting state all the time to produce the potential safety hazard.

In order to solve the above problems, the present application proposes to add a charge and discharge circuit in a relay driving circuit, wherein a capacitor in the charge and discharge circuit is connected to a control circuit to receive a level signal output by the control circuit, and due to the coupling characteristic of the capacitor in the charge and discharge circuit, a switching tube in the driving circuit can be turned on when the control circuit outputs a rectangular wave signal, and meanwhile, the switching tube in the driving circuit can be turned off when the control circuit continuously outputs a high level, so as to prevent a main loop of an electromagnetic heating device from being in a power-on state all the time, and improve safety.

The relay driving circuit provided by the present application is described in detail below with reference to specific embodiments. It is to be understood that the following detailed description may be combined with certain embodiments, and that the same or similar concepts or processes may not be repeated in some embodiments.

Fig. 2 is a first schematic diagram of a relay driving circuit provided in the present application. As shown in fig. 2, the relay 10 drive circuit includes: a switching circuit 20, a charging and discharging circuit 30, and a control circuit 40.

The charging and discharging circuit 30 at least includes a first capacitor, and the first capacitor is connected to the output terminal of the control circuit 40 to receive the level signal of the control circuit 40.

The input terminal of the switching circuit 20 is connected to the charging and discharging circuit 30, and the output terminal thereof is connected to the coil of the relay 10 to be turned on or off under the control of the charging and discharging circuit 30.

In this embodiment, when the control circuit 40 outputs the rectangular wave signal, the first capacitor in the charge/discharge circuit 30 is charged/discharged to control the switching circuit 20 to be turned on, so that the contact of the relay 10 is closed. In this embodiment, the duty ratio of the rectangular wave signal is not specifically limited, and the duty ratio of the rectangular wave signal may be adjusted and set according to actual needs, for example, the duty ratio of the rectangular wave signal may be 50%, that is, the control circuit 40 may output the square wave signal. One or more switching tubes, which may be, for example, a triode, may be included in the switching circuit 20.

When the rectangular wave signal is in a high level state, the control circuit 40 charges the first capacitor in the charge and discharge circuit 30, so that the voltage at the connection point of the charge and discharge circuit 30 and the switch circuit 20 gradually rises, the switch circuit 20 is turned on, the coil of the relay 10 is powered on, the contact is attracted under the action of the magnetic field of the coil, and the main loop of the electromagnetic heating device is powered on and turned on.

When the rectangular wave signal is in a low level state, the first capacitor in the charge and discharge circuit 30 discharges, so as to maintain the voltage at the connection point between the charge and discharge circuit 30 and the switch circuit 20, so that the switch circuit 20 keeps a conducting state, the contact of the relay 10 keeps a pull-in state, and the main loop of the electromagnetic heating device keeps a power-on conducting state.

When the electromagnetic heating device is used up and needs to be turned off, when the control circuit 40 outputs a continuous low-level signal, the first capacitor in the charge and discharge circuit 30 continuously discharges, the voltage at the connection point of the charge and discharge circuit 30 and the switch circuit 20 gradually drops, and when the voltage at the connection point of the charge and discharge circuit 30 and the switch circuit 20 is not enough to maintain the switch circuit 20 to be switched on, the switch circuit 20 is switched off, the coil of the relay 10 is powered off, the contact is disconnected after losing the acting force of the magnetic field, and the main loop of the electromagnetic heating device is powered off.

In the above process, it is explained that when the control circuit 40 normally works, the on or off of the switch circuit is controlled by outputting the rectangular wave driving signal or the continuous low level signal, and further the on or off of the relay is controlled. If the control circuit 40 fails and continuously outputs a high level, the control circuit 40 continuously charges the first capacitor in the charge and discharge circuit 30, and when the first capacitor is fully charged, the first capacitor is open, that is, the charge and discharge circuit 30 is open, so that the switch circuit 20 is turned off, the coil of the relay 10 is powered off, the contact is disconnected due to the loss of the acting force of the magnetic field, and the main loop of the electromagnetic heating device is powered off. It can be seen that when the control circuit 40 fails and continuously outputs a high level, the contact of the relay 10 is opened, thereby ensuring the safety of the electromagnetic heating apparatus.

The relay driving circuit provided by the embodiment utilizes the coupling characteristic of the first capacitor in the charging and discharging circuit, and can normally control the on or off of the switch circuit when the control circuit outputs a rectangular wave driving signal or a continuous low-level signal, so that the on or off of the relay is controlled to ensure the normal work of the electromagnetic heating equipment. When the control circuit is in fault and continuously outputs a high-level signal, the first capacitor is filled and is opened, so that the switching circuit can be switched off, the contact of the relay is switched off, the main loop of the electromagnetic heating equipment is prevented from being continuously electrified in unnecessary time, and the safety is improved.

On the basis of the embodiment shown in fig. 2, the charge and discharge circuit 30 will be described with reference to a specific example.

Fig. 3 is a schematic structural diagram of a relay driving circuit according to the present application. As shown in fig. 3, the driving circuit includes: a switching circuit 20, a charging and discharging circuit 30, and a control circuit 40. The charging and discharging circuit 30 includes a discharging loop 31 in addition to the first capacitor C1.

A first terminal of the first capacitor C1 is connected to the input terminal of the switch circuit 20, and a second terminal of the first capacitor C1 is connected to the output terminal of the control circuit 40 through a first resistor R1.

The discharge circuit 31 is connected to the first terminal of the first capacitor C1 and the input terminal of the switch circuit 20, respectively, and the discharge circuit 31 is grounded.

In one possible implementation, as shown in fig. 4, the discharge circuit 31 includes a first diode D1; a cathode of the first diode D1 is connected to the first terminal of the first capacitor C1 and the input terminal of the switch circuit 20, respectively, and an anode of the first diode D1 is grounded.

In another possible implementation, as shown in fig. 5, the discharge circuit 31 includes a second resistor R2; a first terminal of the second resistor R2 is connected to the first terminal of the first capacitor C1 and the input terminal of the switch circuit 20, respectively, and a second terminal of the second resistor R2 is grounded.

The discharging circuit 31 including the first diode D1 will be described in detail.

When the control circuit 40 outputs a rectangular wave signal, in a high level state of the rectangular wave signal, the control circuit 40 charges the first capacitor C1 in the charging and discharging circuit 30 through the first resistor R1, so that the voltage at the connection point of the first capacitor C1 and the switch circuit 20 is gradually increased, the switch circuit 20 is turned on, the coil of the relay 10 is powered on, the contact is attracted under the action of the magnetic field of the coil, and the main loop of the electromagnetic heating device is powered on and turned on.

In the low level state of the rectangular wave signal, the first capacitor C1 in the charging and discharging circuit 30 forms a loop with the first diode D1 through the first resistor R1 and the ground point of the control circuit 40, such as the ground point of the control chip, to release the electric energy, so as to maintain the voltage at the connection point of the first capacitor C1 and the switching circuit 20, so that the switching circuit 20 maintains the conducting state, the contact of the relay 10 maintains the pull-in state, and the main loop of the electromagnetic heating device maintains the power-on state.

When the electromagnetic heating device needs to be turned off after being used, when the control circuit 40 outputs a continuous low-level signal, the first capacitor C1 continuously discharges, the voltage at the connection point of the first capacitor C1 and the switch circuit 20 gradually drops, and when the voltage at the connection point of the first capacitor C1 and the switch circuit 20 is not enough to maintain the switch circuit 20 to be turned on, the switch circuit 20 is turned off, the coil of the relay 10 is powered off, and the contact is turned off by losing the acting force of the magnetic field, so that the main circuit of the electromagnetic heating device is powered off.

If the control circuit 40 fails and continuously outputs a high level, the control circuit 40 continuously charges the first capacitor C1 in the charging and discharging circuit 30, and when the first capacitor C1 is fully charged, the first capacitor C1 is open, so that the switching circuit 20 is turned off, the coil of the relay 10 is powered off, the contact is disconnected due to the loss of the acting force of the magnetic field, and the main circuit of the electromagnetic heating device is powered off. It can be seen that when the control circuit 40 fails and continuously outputs a high level, the contact of the relay 10 is opened, thereby ensuring the safety of the electromagnetic heating apparatus.

In this embodiment, the first capacitor is discharged through the discharge circuit, so that the switching circuit is kept on when the control circuit outputs the low level state of the rectangular wave signal, and the switching circuit is turned off when the control circuit continuously outputs the low level state, so that the relay is turned on or off, and the normal work of the relay is ensured.

In addition to any of the embodiments shown in fig. 3 to 5, in order to ensure that the charging and discharging power of the charging and discharging circuit 30 can maintain the conduction of the switch circuit 20, a plurality of capacitors may be provided in the charging and discharging circuit 30. For example, as shown in fig. 6, the charging and discharging circuit 30 further includes a second capacitor C2; a first terminal of the second capacitor C2 is connected to the first terminal of the first capacitor C1 and the input terminal of the switch circuit 20, respectively, and a second terminal of the second capacitor C2 is grounded.

When the control circuit 40 outputs a rectangular wave signal, in a high level state of the rectangular wave signal, the control circuit 40 charges the first capacitor C1 and the second capacitor C2 through the first resistor R1, so that the voltage at the connection point of the first capacitor C1 and the switch circuit 20 gradually increases, the switch circuit 20 is turned on, the coil of the relay 10 is powered on, the contact is attracted under the action of the magnetic field of the coil, and the main loop of the electromagnetic heating device is powered on and turned on.

In the low level state of the rectangular wave signal, the first capacitor C1 in the charging and discharging circuit 30 forms a loop with the first diode D1 through the first resistor R1 and the ground point of the control circuit 40, such as the ground point of the control chip, to release the electric energy, and at the same time, the second capacitor C2 discharges similarly, so as to maintain the voltage at the connection point of the first capacitor C1 and the switch circuit 20, so that the switch circuit 20 maintains the conducting state, the contact of the relay 10 maintains the attracting state, and the main loop of the electromagnetic heating device maintains the power-on state.

When the electromagnetic heating device needs to be turned off after being used, when the control circuit 40 outputs a continuous low-level signal, the first capacitor C1 and the second capacitor C2 continuously discharge, the voltage at the connection point of the first capacitor C1 and the switch circuit 20 gradually drops, and when the voltage at the connection point of the first capacitor C1 and the switch circuit 20 is not enough to maintain the switch circuit 20 to be turned on, the switch circuit 20 is turned off, the coil of the relay 10 is powered off, the contact loses the acting force of the magnetic field and is turned off, so that the main circuit of the electromagnetic heating device is powered off.

In this embodiment, the charge and discharge circuit includes first electric capacity and second electric capacity, through the charge and discharge to first electric capacity and second electric capacity, has guaranteed when control circuit output rectangular wave signal, and the voltage of charge and discharge circuit output can maintain switch on of switch circuit, and then control relay switches on, has guaranteed drive circuit's stability.

The switching circuit 20 is further described in detail based on any of the embodiments shown in fig. 2 to 6.

First, a case where one switching tube is included in the switching circuit 20 will be described. Fig. 7 is a sixth circuit diagram of a relay driving circuit provided in the present application. As shown in fig. 7, the switching circuit 20 includes a first switching tube Q1. Optionally, the first switch Q1 is an NPN transistor.

A first end of the first switching tube Q1 is connected with a first end of a coil of the relay 10; the second end of the first switch tube Q1 is grounded through a third resistor R3; the third end of the first switch tube Q1 is connected with the first end of the first capacitor C1 through a fourth resistor R4; a second end of the coil of the relay 10 is connected to a dc power supply. In this embodiment, the control circuit 40 is an MCU.

When the driving signal end of the control circuit 40 outputs a rectangular wave signal, and in a high level state of the rectangular wave signal, the control circuit 40 charges the first capacitor C1 and the second capacitor C2 through the first resistor R1, so that the voltage at the point a of the connection point of the first capacitor C1 and the switching circuit 20 gradually increases, the first switching tube Q1 is turned on, the coil of the relay 10 is powered on, the contact is attracted under the action of the magnetic field of the coil, and the main loop of the electromagnetic heating device is powered on and turned on.

In the low level state of the rectangular wave signal, the first capacitor C1 forms a loop through the first resistor R1, the grounding point of the control circuit 40 and the first diode D1 to release electric energy, and the first diode D2 discharges at the same time, so that the voltage at the point a is maintained, the first switch tube Q1 maintains the conducting state, the contact of the relay 10 maintains the attracting state, and the main loop of the electromagnetic heating device maintains the power-on conducting state.

When the electromagnetic heating equipment is used up and needs to be turned off, the control circuit 40 outputs a continuous low-level signal, the first capacitor C1 and the second capacitor C2 continuously discharge, the voltage at the point A gradually drops, when the voltage at the point A is not enough to maintain the conduction of the first switching tube Q1, the first switching tube Q1 is turned off, the coil of the relay 10 is powered off, the contact is disconnected due to the loss of the acting force of the magnetic field, and the main loop of the electromagnetic heating equipment is powered off.

If the control circuit 40 fails and continuously outputs the high level, the control circuit 40 continuously charges the first capacitor C1 through the first resistor R1, when the first capacitor C1 is fully charged, the first capacitor C1 is opened, the first switching tube Q1 is cut off, the coil of the relay 10 is powered off, the contact loses the acting force of the magnetic field and is disconnected, and the main loop of the electromagnetic heating device is powered off. It can be seen that when the control circuit 40 fails and continuously outputs a high level, the contact of the relay 10 is opened, thereby ensuring the safety of the electromagnetic heating apparatus.

Fig. 7 illustrates an example in which the charging/discharging circuit 30 includes a first capacitor C1, a second capacitor C2, and a first diode D1. It is understood that the charging and discharging circuit 30 may further include a first capacitor C1 and a first diode D1, for example, as shown in fig. 8. Alternatively, the charging and discharging circuit 30 may further include a first capacitor C1 and a second resistor R2.

The relay drive circuit that this embodiment provided, first switch tube among the switch circuit is at the signal of control circuit output, switch on or turn-off under the control of charge-discharge circuit, thereby realized the control to switching on or breaking off of relay contact, and simultaneously, because the coupling characteristic of first electric capacity, can guarantee when control circuit continuously outputs the high level, first electric capacity electric quantity is full of and opens a way, first switch tube ends, make the relay disconnection, the security of major loop has been guaranteed, furthermore, this drive circuit simple structure, easy to realize.

In the above embodiment, the switching circuit 20 includes one switching tube, and the following description describes a case where the switching circuit 20 includes two switching tubes. Fig. 9 is an eighth circuit diagram of a relay driving circuit provided in the present application. As shown in fig. 9, the switching circuit 20 includes a second switching tube Q2 and a third switching tube Q3. Optionally, the second switching tube Q2 is an NPN-type transistor, and the third switching tube Q3 is a PNP-type transistor.

A first end of the second switch tube Q2 is connected to the dc power supply through the fifth resistor R5 and the sixth resistor R6, a second end of the second switch tube Q2 is grounded, and a third end of the second switch tube Q2 is connected to a first end of the first capacitor C1 through the seventh resistor R7.

A first end of the third switching tube Q3 is connected to the dc power supply, a second end of the third switching tube Q3 is connected to a second end of the coil of the relay 10, and a third end of the third switching tube Q3 is connected to the fifth resistor R5 and the sixth resistor R6, respectively.

A first end of the coil of the relay 10 is grounded through an eighth resistor R8.

When the driving signal terminal of the control circuit 40 outputs the rectangular wave signal, in the high level state of the rectangular wave signal, the control circuit 40 charges the first capacitor C1 through the first resistor R1, so that the voltage at the point B of the connection point between the first capacitor C1 and the switch circuit 20 gradually rises, and the second switch tube Q2 gradually becomes saturated and turned on. The direct current power supply, the fifth resistor R5, the sixth resistor R6, the second switch tube Q2 and the ground form a loop, the voltage of a point C of a connection point of the fifth resistor R5 and the sixth resistor R6 is pulled low, the third switch tube Q3 is gradually saturated and conducted, a coil of the relay 10 is electrified, a contact is attracted under the action of a magnetic field of the coil, and a main loop of the electromagnetic heating equipment is electrified and conducted.

In the low level state of the rectangular wave signal, the first capacitor C1 forms a loop with the first diode D1 through the first resistor R1 and the ground point of the control circuit 40, such as the ground end of the MCU, to release the electric energy, and the second capacitor C2 discharges to maintain the voltages at the B point and the C point, the second switch tube Q2 and the third switch tube Q3 maintain the conducting state, the contact of the relay 10 maintains the attracting state, and the main loop of the electromagnetic heating device maintains the power-on state.

When the electromagnetic heating device needs to be turned off after being used, the control circuit 40 outputs a continuous low level signal, the first capacitor C1 and the second capacitor C2 continuously discharge, the voltage at the point B gradually decreases, the voltage at the point C gradually increases, when the voltages at the point B and the point C are not enough to maintain the conduction of the second switch tube Q2 and the third switch tube Q3, the second switch tube Q2 and the third switch tube Q3 are cut off, the coil of the relay 10 is powered off, the contact is disconnected due to the loss of the acting force of the magnetic field, and the main circuit of the electromagnetic heating device is powered off.

If the control circuit 40 fails and continuously outputs a high level, the control circuit 40 continuously charges the first capacitor C1 through the first resistor R1, when the first capacitor C1 is fully charged, the first capacitor C1 is opened, the second switch tube Q2 and the third switch tube Q3 are cut off, the coil of the relay 10 is powered off, the contact is disconnected due to the loss of the acting force of the magnetic field, and the main circuit of the electromagnetic heating device is powered off. It can be seen that when the control circuit 40 fails and continuously outputs a high level, the contact of the relay 10 is opened, thereby ensuring the safety of the electromagnetic heating apparatus.

Fig. 9 illustrates an example in which the charge/discharge circuit 30 includes a first capacitor C1, a second capacitor C2, and a first diode D1. It is understood that the charging and discharging circuit 30 may further include a first capacitor C1 and a first diode D1, for example, as shown in fig. 10. Alternatively, the charging and discharging circuit 30 may further include a first capacitor C1 and a second resistor R2.

The switching circuit in this embodiment includes two switching tubes, and compared with the case that the switching circuit includes one switching tube, the power consumption is lower, and the switching circuit is easier to start.

On the basis of any of the embodiments shown in fig. 1 to 10, the driving circuit of the present application may further include a second diode D2; a second diode D2 is connected in parallel with the coil of the relay 10.

For example, as shown in fig. 11, the control circuit 40 outputs a continuous low level signal, the coil of the relay 10 is powered down, and self-induced electromotive force is generated when the coil of the relay 10 is disconnected, so as to provide a discharge loop through the second diode D2, thereby protecting the first transistor Q1 and preventing the first transistor Q1 from being damaged.

For example, as shown in fig. 12, the control circuit 40 outputs a continuous low level signal, the coil of the relay 10 is powered down, and self-induced electromotive force is generated when the coil of the relay 10 is disconnected, so as to provide a discharge loop through the second diode D2, thereby protecting the third transistor Q3 and preventing the third transistor Q3 from being damaged.

On the basis of any of the above embodiments, the driving circuit of the present application may further include a fault detection circuit. As shown in fig. 13, the failure detection circuit 50 is connected to the coil of the relay 10 and the input terminal of the control circuit 40, respectively.

When the control circuit 40 outputs the rectangular wave drive signal, the switching circuit 20 is kept in the on state, and the coil of the relay 10 is kept in the power-on state, so that the voltage at the connection point of the fault detection circuit 50 and the coil of the relay 10 is kept at a relatively stable voltage value, for example, within a voltage value range. However, if the relay 10 or the drive circuit malfunctions, for example, if the relay 10 is short-circuited, the voltage at the connection point of the failure detection circuit 50 and the coil of the relay 10 rises, or if the relay 10 coil is open, the voltage drop at the connection point of the failure detection circuit 50 and the coil of the relay 10 becomes zero. The fault detection circuit 50 may feed back the detected voltage variation to the control circuit 40, so that the control circuit 40 may determine whether the relay 10 and/or the driving circuit of the relay 10 is faulty according to the voltage variation.

Illustratively, as shown in fig. 14 or fig. 15, the fault detection circuit 50 includes a ninth resistor R9 and a third capacitor C3. A first end of a ninth resistor R9 is connected with a first end of a coil of the relay 10, and a second end of the ninth resistor R9 is connected with a first end of a third capacitor C3 and an input end of the control circuit 40, respectively; the second terminal of the third capacitor C3 is connected to ground.

When the relay 10 and/or the driving circuit of the relay 10 fail, such as the voltage at the point D in fig. 14 or the voltage at the point E in fig. 15 changes, an abnormal voltage signal is fed back to the control circuit 40 through the integrating circuit formed by the ninth resistor R9 and the third capacitor C3, and the control circuit 40 can close the driving signal output to cut off the main loop, thereby further improving the safety of the electromagnetic heating device. In addition, the control circuit 40 can control the corresponding display unit and/or voice unit to feed back the fault to the user by means of display and/or prompt tone.

The present application may also provide an electromagnetic heating apparatus including a relay 10 and a relay 10 driving circuit; the relay 10 is connected with the main loop of the electromagnetic heating device to control the on or off of the main loop of the electromagnetic heating device. The driving circuit of the relay 10 is the driving circuit in any of the above embodiments, and the implementation principle and the technical effect are similar, and are not described herein again.

It will be apparent to those skilled in the art that various changes and modifications may be made in the embodiments of the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to encompass such modifications and variations.

In the present application, the terms "include" and variations thereof may refer to non-limiting inclusions; the term "or" and variations thereof may mean "and/or". The terms "first," "second," and the like in this application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. In the present application, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

Claims

1. A relay (10) drive circuit, comprising: a switching circuit (20), a charging and discharging circuit (30) and a control circuit (40);

the charging and discharging circuit (30) at least comprises a first capacitor C1, and the first capacitor C1 is connected with the output end of the control circuit (40) to receive a level signal of the control circuit (40);

the input end of the switch circuit (20) is connected with the charge and discharge circuit (30), and the output end of the switch circuit is connected with the coil of the relay (10) so as to be switched on or off under the control of the charge and discharge circuit (30).

2. The drive circuit according to claim 1, wherein the charge and discharge circuit (30) further comprises a discharge loop (31);

a first end of the first capacitor C1 is connected with an input end of the switch circuit (20), and a second end of the first capacitor C1 is connected with an output end of the control circuit (40) through a first resistor R1;

the discharge loop (31) is respectively connected with the first end of the first capacitor C1 and the input end of the switch circuit (20), and the discharge loop (31) is grounded.

3. The driving circuit according to claim 2, wherein the charging and discharging circuit (30) further comprises a second capacitor C2;

the first end of the second capacitor C2 is connected with the first end of the first capacitor C1 and the input end of the switch circuit (20), and the second end of the second capacitor C2 is grounded.

4. The driver circuit according to claim 2, wherein the discharge loop (31) comprises a first diode D1;

the cathode of the first diode D1 is connected with the first end of the first capacitor C1 and the input end of the switch circuit (20), respectively, and the anode of the first diode D1 is grounded.

5. The driver circuit according to claim 2, wherein the discharge circuit (31) comprises a second resistor R2;

the first end of the second resistor R2 is connected with the first end of the first capacitor C1 and the input end of the switch circuit (20), and the second end of the second resistor R2 is grounded.

6. The driver circuit according to any of claims 2-5, wherein the switching circuit (20) comprises a first switching tube Q1;

a first end of the first switching tube Q1 is connected with a first end of a coil of the relay (10); a second end of the first switch tube Q1 is grounded through a third resistor R3; the third end of the first switch tube Q1 is connected to the first end of the first capacitor C1 through a fourth resistor R4;

and the second end of the coil of the relay (10) is connected with a direct current power supply.

7. The driving circuit according to any of claims 2-5, wherein the switching circuit (20) comprises a second switching tube Q2 and a third switching tube Q3;

a first end of the second switching tube Q2 is connected to a dc power supply through a fifth resistor R5 and a sixth resistor R6, a second end of the second switching tube Q2 is grounded, and a third end of the second switching tube Q2 is connected to a first end of the first capacitor C1 through a seventh resistor R7;

a first end of the third switching tube Q3 is connected to the dc power supply, a second end of the third switching tube Q3 is connected to a second end of the coil of the relay (10), and a third end of the third switching tube Q3 is connected to the fifth resistor R5 and the sixth resistor R6, respectively;

a first end of a coil of the relay (10) is grounded through an eighth resistor R8.

8. The driving circuit according to any of claims 1-5, further comprising a second diode D2;

the second diode D2 is connected in parallel with the coil of the relay (10).

9. The drive circuit according to any one of claims 1 to 5, wherein the drive circuit further comprises: a fault detection circuit (50);

the fault detection circuit (50) is connected with the coil of the relay (10) and the input end of the control circuit (40) respectively.

10. The driver circuit according to claim 9, wherein the fault detection circuit (50) comprises a ninth resistor R9 and a third capacitor C3;

a first end of the ninth resistor R9 is connected with a first end of a coil of the relay (10), and a second end of the ninth resistor R9 is respectively connected with a first end of the third capacitor C3 and an input end of the control circuit (40);

the second terminal of the third capacitor C3 is grounded.

11. An electromagnetic heating apparatus, characterized by comprising a relay (10) and a relay (10) drive circuit; the relay (10) drive circuit is the relay (10) drive circuit according to any one of claims 1 to 10.