CN220873488U - Relay driving circuit and switching circuit - Google Patents

Abstract

The application discloses a relay driving circuit and a switching circuit, and relates to the technical field of circuits. Comprising the following steps: a power supply connected to a first end of the coil of the relay; the first field effect transistor, the second field effect transistor and the third field effect transistor; the first end of the capacitor is connected with the power supply and the first end of the coil, and the second end of the capacitor is connected with the second end of the third field effect transistor; the first field effect tube, the second field effect tube and the third field effect tube are used for controlling the power supply to charge the capacitor, or controlling the power supply and the charged capacitor to jointly provide the coil with pull-in instantaneous voltage so as to enable the contacts of the relay to be pulled in. The relay driving circuit of the single power supply is provided with the capacitor and the three field effect transistors for controlling the capacitor to charge and discharge, so that the power supply and the charged capacitor can jointly provide the coil with the actuation instantaneous voltage, the design of the circuit is simplified, the preparation cost of the circuit is reduced, the heat loss of the relay during contact actuation is reduced, and the service life of the relay is prolonged.

Description

Relay driving circuit and switching circuit

Technical Field

The application relates to the technical field of circuits, in particular to a relay driving circuit and a switching circuit.

Background

A conventional Relay (Relay) is an electronic control device, and is an "automatic switch" capable of controlling a larger current with a smaller current, and is generally applied to an automatic control circuit. The driving voltage required by the relay at the conduction moment is higher than the voltage required by the relay to maintain the conduction state, and the relay is conducted and turned off by arranging a relay driving circuit connected with the relay.

In the related art, if the relay driving circuit adopts dual power supply driving, the circuit design is complex, and the required devices of the circuit are more and the preparation cost is higher, while if the relay driving circuit adopts single power supply driving, more heat loss is generated when the relay maintains the on state, and the service life of the relay is reduced.

Disclosure of utility model

The application provides a relay driving circuit and a switching circuit.

In a first aspect, an embodiment of the present application provides a relay driving circuit, including: a power supply for connecting a first end of a coil of the relay; the first end of the first field effect tube is connected with the power supply; the first end of the second field effect tube is grounded, and the second end of the second field effect tube is connected with the second end of the first field effect tube and the second end of the coil; the first end of the third field effect tube is grounded, the second end of the third field effect tube is connected with the third end of the first field effect tube, and the third end of the third field effect tube is connected with the power supply; the first end of the capacitor is connected with the power supply and is used for being connected with the first end of the coil, and the second end of the capacitor is connected with the second end of the third field effect tube; the first field effect transistor, the second field effect transistor and the third field effect transistor are used for controlling the power supply to charge the capacitor, or controlling the power supply and the charged capacitor to jointly provide attraction instantaneous voltage for the coil so as to attract contacts of the relay.

Optionally, the first field effect transistor, the second field effect transistor and the third field effect transistor are further configured to control the power supply to provide a pull-in holding voltage for the coil to keep the contact continuously pulled in when the capacitor discharges, where the pull-in holding voltage is smaller than the pull-in transient voltage.

Optionally, the relay driving circuit further includes a driving signal source, the driving signal source is connected with the third end of the second field effect transistor, the driving signal source is used for outputting a driving signal, and the driving signal is used for driving the second field effect transistor to be conducted.

Optionally, the conducting conditions of the first field effect tube and the second field effect tube are opposite, the conducting conditions of the second field effect tube and the third field effect tube are the same, the first field effect tube is conducted in a low level, and the second end of the first field effect tube is grounded through the conducted second field effect tube.

Optionally, the power supply is configured to provide a driving voltage for the third field effect transistor when the driving signal source does not output the driving signal, where the driving voltage is used to drive the third field effect transistor to be turned on.

Optionally, the first field effect transistor and the second field effect transistor are N-type metal oxide semiconductor field effect transistors, and the third field effect transistor is a P-type metal oxide semiconductor field effect transistor.

Optionally, the relay driving circuit further includes a first resistor, a first end of the first resistor is connected to the power supply, and a second end of the first resistor is connected to a third end of the third field effect transistor.

Optionally, the relay driving circuit further includes a first diode, an anode of the first diode is connected to the second end of the first resistor, and a cathode of the first diode is connected to the third end of the second field effect transistor.

Optionally, the relay driving circuit further includes a second diode, an anode of the second diode is connected to the power supply and the first end of the first field effect transistor, and a cathode of the second diode is connected to the first end of the capacitor.

Optionally, the relay driving circuit further includes a second resistor and a third resistor; the first end of the second resistor is connected with the power supply, and the second end of the second resistor is connected with the second end of the first field effect transistor; the first end of the third resistor is connected with the second end of the second resistor, and the second end of the third resistor is connected with the second end of the second field effect transistor.

In a second aspect, an embodiment of the present application provides a switching circuit, including a relay and the relay driving circuit described above, where the relay is connected to the relay driving circuit.

The relay driving circuit provided by the embodiment of the application comprises: the power supply is used for being connected with the first end of the coil of the relay; the first end of the first field effect tube is connected with a power supply; the first end of the second field effect tube is grounded, and the second end of the second field effect tube is connected with the second end of the first field effect tube and the second end of the coil; the first end of the third field effect tube is grounded, the second end of the third field effect tube is connected with the third end of the first field effect tube, and the third end of the third field effect tube is connected with a power supply; the first end of the capacitor is connected with a power supply and is used for being connected with the first end of the coil, and the second end of the capacitor is connected with the second end of the third field effect transistor; the first field effect tube, the second field effect tube and the third field effect tube are used for controlling the power supply to charge the capacitor, or controlling the power supply and the charged capacitor to jointly provide the coil with pull-in instantaneous voltage so as to enable the contacts of the relay to be pulled in. By arranging the capacitor and the first field effect transistor, the second field effect transistor and the third field effect transistor which can realize the charge and discharge control of the capacitor, the relay driving circuit driven by a single power supply can provide attraction instantaneous voltage for the coil of the relay through the power supply and the charged capacitor, and realize the action of driving the contact of the relay to be closed, thereby avoiding the arrangement of an auxiliary power supply, simplifying the design of a circuit, reducing electronic elements required by the circuit and further reducing the preparation cost of the circuit; meanwhile, after the contact is attracted by the capacitor, the heat loss of the relay is lower when the relay driving circuit maintains the contact attraction, so that the service temperature of the relay is reduced, and the service life of the relay is prolonged.

These and other aspects of the application will be more readily apparent from the following description of the embodiments.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 shows a schematic circuit diagram of a relay driving circuit according to an embodiment of the present application.

Fig. 2 shows a schematic circuit diagram of a relay driving circuit according to another embodiment of the present application.

Fig. 3 shows a schematic circuit diagram of a relay driving circuit according to another embodiment of the present application.

Fig. 4 is a schematic diagram of a switch circuit according to an embodiment of the application.

Detailed Description

In order to enable those skilled in the art to better understand the present application, a clear and complete description of the technical solution in the present embodiment will be provided below with reference to the accompanying drawings in the present embodiment. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The terms "first," "second," and the like in this disclosure are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

The relay has a control system and a controlled system, and can play roles of automatic regulation, safety protection, a switching circuit and the like in a circuit. The traditional relay comprises two parts, namely a coil (a control system) and a contact (a controlled system), and by controlling the voltage input to the coil of the relay, certain current flows in the coil to generate electromagnetic effect, so that the coil of the relay can control the attractive force generated by the contact of the relay, thereby controlling the actuation and release of the contact of the relay to realize the function of a switch, and the relay needs a relay driving circuit to control the power supply of the relay so as to realize the actuation of the contact of the relay.

The contact of the relay needs to generate larger attractive force to generate the attraction action at the attraction moment, and the attractive force required by the electric shock of the relay when the relay is kept in the attraction state is smaller. Therefore, at the actuation moment of the contacts of the relay, the relay needs to provide a larger actuation moment voltage by the relay driving circuit to complete actuation, and when the contacts of the relay keep the actuation state, the actuation holding voltage required by the relay is smaller than the actuation moment voltage.

In the related art, the relay driving method is generally classified into two types. In the driving mode of adopting double power supplies, the high-voltage power supply is used for providing the pull-in instantaneous voltage for the relay, and then the low-voltage power supply is switched to continuously provide pull-in holding voltage for the relay, so that coil loss is reduced, but due to the fact that the extra auxiliary power supply is provided, multiple paths of power supply outputs exist in the driving circuit, the circuit design is complex, the number of devices required by the circuit is large, the size of a circuit board is increased, and the manufacturing cost is increased. The circuit structure of the driving circuit in the driving mode of adopting a single constant power supply is simple, but more heat is generated in the coil of the relay when the electric shock of the relay maintains the attraction state, and the ageing of the relay is easy to cause, so that the service life of the relay is reduced.

Referring to fig. 1, fig. 1 is a schematic circuit diagram of a relay driving circuit 1 according to an embodiment of the application. The relay driving circuit 1 provided in the embodiment of the present application will be described in detail with reference to fig. 1. As shown in fig. 1, the relay driving circuit 1 of the present application includes a power supply 10, a first fet 20, a second fet 30, a third fet 40, and a capacitor 50.

The relay 2 comprises a coil 21 and a contact 22, and the relay driving circuit 1 is connected with the coil 21 of the relay 2 and is used for providing a pull-in instantaneous voltage or a pull-in holding voltage for the coil 21 of the relay 2 so as to control the pull-in of the contact 22 of the relay 2.

In the relay driving circuit 1 of the present embodiment, the power source 10 is connected to the first end of the capacitor 50, and the power source 10 is used to connect to the first end of the coil 21 of the relay 2. A first end of the capacitor 50 is connected to the power supply 10, and a first end of the capacitor 50 is connected to the first end of the coil 21, and a second end of the capacitor 50 is connected to the second end of the third fet 40.

Optionally, a first end of the first fet 20 is connected to the power source 10, and a first end of the first fet 20 is used to connect to a first end of the coil 21 of the relay 2, a second end of the first fet 20 is connected to a second end of the second fet 30, and a third end of the first fet 20 is connected to a second end of the capacitor 50. The first end of the second field effect tube 30 is grounded, the second end of the second field effect tube 30 is connected with the second end of the first field effect tube 20 and the third end of the third field effect tube 40, and the second end of the second field effect tube 30 is used for being connected with the second end of the coil 21 of the relay 2. The first end of the third fet 40 is grounded, the second end of the third fet 40 is connected to the third end of the first fet 20 and the second end of the capacitor 50, and the third end of the third fet 40 is connected to the power supply 10.

In this embodiment, the first fet 20, the second fet 30, and the third fet 40 are used to control the power supply 10 to charge the capacitor 50, or control the power supply 10 and the charged capacitor 50 together provide the coil 21 with an actuation transient voltage, so that the contact 22 of the relay 2 is actuated.

Optionally, by controlling the second fet 30 to turn off, when the second fet 30 turns off, the first fet 20 turns off and the third fet 40 turns on, the first end of the capacitor 50 is connected to the power supply 10, the second end of the capacitor 50 is grounded through the turned-on third fet 40, and the power supply 10 charges the capacitor 50. By controlling the second field effect transistor 30 to be turned on, the first field effect transistor 20 is turned on and the third field effect transistor 40 is turned off when the second field effect transistor 30 is turned on, the second end of the charged capacitor 50 is connected with the power supply 10 through the turned-on first field effect transistor 20, the first end of the capacitor 50 is connected with the first end of the relay 2, and the fact that the charged capacitor 50 and the power supply 10 are controlled to jointly provide the attraction instantaneous voltage for the coil 21 is achieved.

In this embodiment, when the charged capacitor 50 and the power supply 10 together provide the coil 21 with the actuation transient voltage, the capacitor 50 has the characteristics of high voltage, short time, small energy and large transient power in the discharging process, so that when the power supply 10 and the charged capacitor 50 provide the actuation transient voltage to the coil 21 of the relay 2, the coil 21 of the relay 2 can generate sufficient attraction force to the contact 22 of the relay 2, and the action of driving the contact 22 of the relay 2 to close is realized. And after the capacitor 50 is discharged, the charge in the capacitor 50 can be automatically supplemented by the power supply 10 in the relay driving circuit 1 for the next use.

Further, the first fet 20, the second fet 30, and the third fet 40 are further configured to control the power supply 10 to provide the coil 21 with the pull-in holding voltage to keep the contact 22 continuously pulled in when the capacitor 50 is discharged. After the capacitor 50 is discharged, when the second fet 30 is controlled to be continuously turned on, the power supply 10 continuously discharges the coil 21 of the relay 2 to provide the coil 21 of the relay 2 with the pull-in holding voltage, and the pull-in holding voltage of the relay 2 is smaller than the pull-in transient voltage.

The relay driving circuit 1 of the embodiment of the present application includes: a power supply 10, the power supply 10 being for connection to a first end of a coil 21 of the relay 2; the first end of the first field effect tube 20 is connected with the power supply 10; the second field effect tube 30, the first end of the second field effect tube 30 is grounded, the second end of the second field effect tube 30 connects the second end of the first field effect tube 20 and is used for connecting the second end of the coil 21; the first end of the third field effect tube 40 is grounded, the second end of the third field effect tube 40 is connected with the third end of the first field effect tube 20, and the third end of the third field effect tube 40 is connected with the power supply 10; a capacitor 50, wherein a first end of the capacitor 50 is connected with the power supply 10 and is used for being connected with a first end of the coil 21, and a second end of the capacitor 50 is connected with a second end of the third field effect transistor 40; the first fet 20, the second fet 30, and the third fet 40 are used to control the power supply 10 to charge the capacitor 50, or control the power supply 10 and the charged capacitor 50 together to provide the coil 21 with an actuation transient voltage, so that the contact 22 of the relay 2 is actuated. In the relay driving circuit 1 driven by the single power supply 10, through the arrangement of the capacitor 50 and the first field effect transistor 20, the second field effect transistor 30 and the third field effect transistor 40 capable of realizing the charge and discharge control of the capacitor 50, the coil 21 of the relay 2 can be provided with the attraction instantaneous voltage through the power supply 10 and the charged capacitor 50, the action of driving the contact 22 of the relay 2 to be closed is realized, and the power supply 10 can provide the attraction holding voltage for the coil 21 to keep the contact 22 to be attracted continuously when the discharge of the capacitor 50 is finished, so that the arrangement of the auxiliary power supply 10 to provide two different attraction voltages for the relay 2 is avoided, the design of a circuit is simplified, electronic elements required by the circuit are reduced, and the preparation cost of the circuit is further reduced. Meanwhile, after the capacitor 50 is arranged to enable the contact 22 to be attracted, when the power supply 10 singly provides attraction and holding voltage for the relay 2, the heat loss in the relay 2 is low, so that the service temperature of the relay 2 is reduced, and the service life of the relay 2 is prolonged.

Referring to fig. 2, fig. 2 is a schematic circuit diagram of a relay driving circuit 1 according to another embodiment of the application. As shown in fig. 2, the relay driving circuit 1 of the present embodiment includes a power supply 10, a first fet 20, a second fet 30, a third fet 40, and a capacitor 50.

Optionally, the relay driving circuit 1 further includes a driving signal source 60, where the driving signal source 60 is connected to the third terminal of the second fet 30, and the driving signal source 60 is configured to output a driving signal, and the driving signal is configured to drive the second fet 30 to be turned on.

Alternatively, the conducting conditions of the first fet 20 and the second fet 30 are opposite, the conducting conditions of the second fet 30 and the third fet 40 are the same, and the first fet 20 is turned on at a low level, i.e., the first fet is turned on when the second terminal of the first fet 20 is grounded, and the second fet 30 is turned on at a high level with the third fet 40.

Further, the power supply 10 is configured to provide a driving voltage for the third fet 40 when the driving signal source 60 does not output a driving signal, and the driving voltage is used to drive the third fet 40 to be turned on.

The first fet 20 and the second fet 30 are N-type mosfets, and the third fet 40 is a P-type mosfet. The second end of the first field effect tube 20 is a gate, the first end of the first field effect tube 20 is a source and the third end of the first field effect tube 20 is a drain, or the first end of the first field effect tube 20 is a drain and the third end of the first field effect tube 20 is a source. The third end of the second field effect transistor 30 is a gate, the first end of the second field effect transistor 30 is a source and the second end of the second field effect transistor 30 is a drain, or the first end of the second field effect transistor 30 is a drain and the second end of the second field effect transistor 30 is a source. The third end of the third field effect transistor 40 is a gate, the first end of the third field effect transistor 40 is a source and the second end of the third field effect transistor 40 is a drain, or the first end of the third field effect transistor 40 is a drain and the second end of the third field effect transistor 40 is a source.

In the present embodiment, during the process of controlling the power supply 10 to charge the capacitor 50 by the first fet 20, the second fet 30, and the third fet 40: when the driving signal source 60 does not output the driving signal, the second fet 30 in the relay driving circuit 1 is turned off, the second end of the coil 21 of the relay 2 cannot be grounded through the turned-off second fet 30, the power supply 10 does not discharge the coil 21 of the relay 2, and at the same time, the second end of the first fet 20 cannot be grounded through the turned-off second fet 30, and the first fet 20 is turned off. When the second fet 30 is turned off, the third end of the third fet 40 is connected to the power supply 10, and the power supply 10 provides a driving voltage for the third fet 40 to drive the third fet 40 to turn on, so that the second end of the capacitor 50 is grounded through the turned-on third fet 40. The first terminal of the capacitor 50 is connected to the power supply 10, and the second terminal of the capacitor 50 is grounded, thereby enabling control of the power supply 10 to charge the capacitor 50 when a potential difference exists across the capacitor 50.

Optionally, in the process that the first fet 20, the second fet 30, and the third fet 40 control the power supply 10 and the charged capacitor 50 together provide the coil 21 with the pull-in transient voltage, so that the contact 22 of the relay 2 is pulled in: when the driving signal source 60 outputs the driving signal, the second field effect transistor 30 in the relay driving circuit 1 is turned on, and the second end of the coil 21 of the relay 2 is grounded through the turned-on second field effect transistor 30, so that the control power supply 10 discharges the coil 21 of the relay 2. And when the second fet 30 is turned on, the second end of the first fet 20 and the third end of the third fet 40 are grounded through the turned-on second fet 30, when the second end of the first fet 20 is grounded, the first fet 20 is turned on, the third end of the third fet 40 is grounded, the power supply 10 no longer provides driving voltage for the third fet 40, and the third fet 40 is turned off. The second end of the charged capacitor 50 is connected with the power supply 10 through the conducted first field effect transistor 20, and the first end of the capacitor 50 is connected with the first end of the relay 2, so that the charged capacitor 50 and the power supply 10 are controlled to be matched to discharge the coil 21 of the relay 2 together. Based on this, by controlling the second fet 30 to be turned on, the on-state of the first fet 20 and the off-state of the third fet 40 are controlled, so that the control power supply 10 and the charged capacitor 50 together provide the pull-in transient voltage to the coil 21.

Optionally, when the discharging of the capacitor 50 is finished, the first fet 20, the second fet 30, and the third fet 40 control the power supply 10 to provide the coil 21 with the pull-in holding voltage, so as to keep the contact 22 of the relay 2 continuously pulled in the process: the driving signal source 60 continuously outputs a driving signal to control the second fet 30 to maintain the on state, at this time, the first fet 20 is turned on and the third fet 40 is turned off, the second end of the coil 21 of the relay 2 is grounded through the turned-on second fet 30, the power supply 10 continuously discharges the coil 21 of the relay 2, and at this time, only the power supply 10 provides the pull-in holding voltage for the coil 21 of the relay 2.

In this embodiment, by setting the conduction conditions of the first fet 20 and the second fet 30 opposite, the conduction conditions of the second fet 30 and the third fet 40 are the same, when the second fet 30 is turned off, the first fet 20 is turned off and the second fet 30 is turned on, the power supply 10 charges the capacitor 50, and when the second fet 30 is turned on, the first fet 20 is turned on and the second fet 30 is turned off, and the power supply 10 and the capacitor 50 discharge the coil 21 of the relay 2. Based on this, only one driving signal source 60 for outputting driving signals to control the second fet 30 to be turned on is provided in the relay driving circuit 1 driven by the single power supply 10, so that charging and discharging control of the capacitor 50 can be completed, and at the same time, attraction and release control of the contacts 22 of the relay 2 can be realized, so that the design of the relay driving circuit 1 is simplified, and electronic elements required by the circuit are reduced, thereby reducing the manufacturing cost of the circuit.

Referring to fig. 3, fig. 3 is a schematic circuit diagram of a relay driving circuit 1 according to another embodiment of the application. As shown in fig. 3, the relay driving circuit 1 of the present embodiment includes a power supply 10, a first fet 20, a second fet 30, a third fet 40, a capacitor 50, and a driving signal source 60.

Optionally, the relay driving circuit 1 further includes a first resistor 70, a first end of the first resistor 70 is connected to the power supply 10, a second end of the first resistor 70 is connected to the third end of the third fet 40, and when the second fet 30 is turned off, the power supply 10 is configured to output a driving voltage to the third end of the third fet 40 through the first resistor 70 to control the third fet 40 to be turned on.

Further, the relay driving circuit 1 further includes a first diode 80, wherein an anode of the first diode 80 is connected to the second end of the first resistor 70, and a cathode of the first diode 80 is connected to the third end of the second fet 30. The diode is used as a device with two electrodes, only current is allowed to flow from one direction, the current can flow from the anode to the cathode of the diode, and the current is blocked when the current flows from the cathode to the anode of the diode.

Alternatively, when the driving signal source 60 does not output a driving signal, that is, when the second fet 30 is turned off and the third fet 40 is turned on, no current passes through the first diode 80, and the driving voltage output from the power supply 10 is output to the third terminal of the third fet 40 through the first resistor 70. When the driving signal source 60 outputs a driving signal, that is, when the second fet 30 is turned on, there is a current passing through the first diode 80, at this time, the driving voltage provided by the power supply 10 for driving the third fet 40 to be turned on flows to the cathode of the first diode 80 through the anode of the first diode 80, and is transmitted to the ground through the turned-on second fet 30, and the third fet 40 is turned off.

Optionally, the relay driving circuit 1 further includes a second diode 90, where an anode of the second diode 90 is connected to the power source 10 and the first end of the first field effect transistor 20, and a cathode of the second diode 90 is connected to the first end of the capacitor 50. When the driving signal source 60 outputs the driving signal and the second fet 30 is turned on, the second end of the coil 21 of the relay 2 is grounded through the turned-on second fet 30, and the second end of the first fet 20 is grounded through the turned-on second fet 30 and turned on at a low level, so that the first end of the capacitor 50 is connected to the power supply 10 through the turned-on first fet 20. At this time, the capacitor 50 and the power supply 10 jointly discharge the coil 21 of the relay 2, and the current output by the capacitor 50 cannot be transmitted to the power supply 10 through the cathode of the second diode 90 to the anode of the second diode 90, so that the influence of the discharged capacitor 50 on the operation of the power supply 10 is avoided.

In the present embodiment, the relay driving circuit 1 further includes a second resistor 100 and a third resistor 110. The first end of the second resistor 100 is connected to the power supply 10, the second end of the second resistor 100 is connected to the second end of the first fet 20, and the second resistor 100 is configured to provide a gate current to the first fet 20 during the on-state of the first fet 20. The first end of the third resistor 110 is connected to the second end of the second resistor 100 and the second end of the first fet 20, the second end of the third resistor 110 is connected to the second end of the second fet 30, and the third resistor 110 is configured to connect the second end of the first fet 20 to ground through the turned-on second fet 30 when the driving signal source 60 outputs the driving signal to control the second fet 30 to be turned on, so that the first fet 20 is turned on at a low level.

In the embodiment of the application, by arranging the first diode 80 and the second diode 90 which are in unidirectional conduction, the relay driving circuit 1 realizes conduction protection on the circuit in the process of controlling the conduction and the disconnection of the first field effect transistor 20, the second field effect transistor 30 and the third field effect transistor 40 and the charging and discharging of the capacitor 50, so that the circuit can safely operate. Meanwhile, through the arrangement of the first resistor 70, the second resistor 100 and the third resistor 110, only one driving signal source 60 for outputting driving signals to control the second field effect transistor 30 to be conducted is arranged in the relay driving circuit 1, the conduction and the disconnection of the first field effect transistor 20 and the third field effect transistor 40 can be realized, the use of the auxiliary driving signal source 60 in the circuit is reduced, the occupied area of the circuit is reduced, and the preparation cost of the circuit is reduced.

Referring to fig. 4, fig. 4 is a schematic diagram illustrating a structure of a switching circuit 3 according to an embodiment of the application. As shown in fig. 4, the switching circuit 3 provided in the present embodiment includes the relay 2 and the relay driving circuit 1 provided in the foregoing embodiment.

Alternatively, the relay 2 includes a coil 21 and a contact 22, the relay driving circuit 1 is connected to the coil 21 of the relay 2, and the relay 2 is connected to the relay driving circuit 1 for supplying an actuation transient voltage or actuation holding voltage to the coil 21 of the relay 2 to control actuation of the contact 22 of the relay 2. The relay driving circuit 1 is driven by a single power supply, and the using area of the relay driving circuit 1 is small, so that the size of the switch circuit 1 is reduced.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be appreciated by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not drive the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (11)

1. A relay driving circuit, comprising:

a power supply for connecting a first end of a coil of the relay;

The first end of the first field effect tube is connected with the power supply;

The first end of the second field effect tube is grounded, and the second end of the second field effect tube is connected with the second end of the first field effect tube and the second end of the coil;

The first end of the third field effect tube is grounded, the second end of the third field effect tube is connected with the third end of the first field effect tube, and the third end of the third field effect tube is connected with the power supply;

The first end of the capacitor is connected with the power supply and is used for being connected with the first end of the coil, and the second end of the capacitor is connected with the second end of the third field effect tube;

The first field effect transistor, the second field effect transistor and the third field effect transistor are used for controlling the power supply to charge the capacitor, or controlling the power supply and the charged capacitor to jointly provide attraction instantaneous voltage for the coil so as to attract contacts of the relay.

2. The relay driving circuit according to claim 1, wherein the first field effect transistor, the second field effect transistor, and the third field effect transistor are further configured to control the power supply to supply the pull-in holding voltage to the coil to hold the contact in continuous pull-in, when the capacitor discharge is ended, the pull-in holding voltage being smaller than the pull-in transient voltage.

3. The relay driving circuit according to claim 1, further comprising a driving signal source connected to the third terminal of the second field effect transistor, the driving signal source being configured to output a driving signal for driving the second field effect transistor to be turned on.

4. The relay driving circuit according to claim 3, wherein the conduction condition of the first field effect transistor and the second field effect transistor is opposite, the conduction condition of the second field effect transistor and the third field effect transistor is the same, the first field effect transistor is turned on at a low level, and the second end of the first field effect transistor is grounded through the turned-on second field effect transistor.

5. The relay driving circuit according to claim 4, wherein the power supply is configured to supply a driving voltage to the third field effect transistor for driving the third field effect transistor to be turned on in a case where the driving signal source does not output the driving signal.

6. The relay driving circuit according to claim 4, wherein the first field effect transistor and the second field effect transistor are N-type metal oxide semiconductor field effect transistors, and the third field effect transistor is a P-type metal oxide semiconductor field effect transistor.

7. The relay driver circuit according to any one of claims 1 to 6, further comprising a first resistor, a first end of the first resistor being connected to the power supply, and a second end of the first resistor being connected to a third end of a third field effect transistor.

8. The relay driver circuit of claim 7 further comprising a first diode, wherein a positive electrode of the first diode is connected to the second end of the first resistor and a negative electrode of the first diode is connected to the third end of the second field effect transistor.

9. The relay driving circuit according to any one of claims 1 to 6, further comprising a second diode, wherein an anode of the second diode is connected to the power source and the first end of the first field effect transistor, and a cathode of the second diode is connected to the first end of the capacitor.

10. The relay driving circuit according to any one of claims 1 to 6, further comprising a second resistor and a third resistor;

The first end of the second resistor is connected with the power supply, and the second end of the second resistor is connected with the second end of the first field effect transistor;

The first end of the third resistor is connected with the second end of the second resistor, and the second end of the third resistor is connected with the second end of the second field effect transistor.

11. A switching circuit comprising a relay and a relay driving circuit according to any one of claims 1 to 10, the relay being connected to the relay driving circuit.