Control circuit, control method for a relay and switching device

Abstract

The application discloses a control circuit and method of a relay and a switching device, and relates to the technical field of electronics. A processing circuit can control a second switch circuit to be turned on in response to a turn-on instruction for the relay, so that the relay is closed. That is, the processing circuit can automatically control the relay to be closed, thus improving the control flexibility of the relay. Since the processing circuit controls the second switch circuit to be turned on to make the relay closed when a square wave signal output by a zero-crossing detection circuit jumps from a first level to a second level, that is, at the current zero-crossing point of alternating current, the phenomenon of sparking and arc drawing of the contact of the relay can be avoided, so that the service life of the relay can be prolonged.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and in particular to a control circuit, control method and switching device for a relay. Background Technology

[0002] Home appliances can be connected to mains power to operate. Even after a home appliance is turned off, it will still consume electricity if it remains connected to mains power. To reduce energy loss, users can use switching devices (such as sockets) to connect home appliances to the mains power.

[0003] After home appliances stop working, users can manually control the switch to turn them off to disconnect them from the mains power. When home appliances need to work, users can manually control the switch to turn them back on to connect them to the mains power.

[0004] However, the above-mentioned methods for controlling the closing of switching devices have low flexibility. Summary of the Invention

[0005] This application provides a relay control circuit, control method, and switching device, which can solve the problem of low flexibility in the closing method of control switching devices in related technologies. The technical solution is as follows:

[0006] On the one hand, a control circuit for a relay is provided, the control circuit comprising: a zero-crossing detection circuit, a first switching circuit, a processing circuit, a second switching circuit, and a DC power supply;

[0007] The input terminal of the zero-crossing detection circuit is used to receive AC power, and the output terminal of the zero-crossing detection circuit is connected to the control terminal of the first switching circuit and the first terminal of the processing circuit, respectively. The zero-crossing detection circuit is used to output a square wave signal based on the AC power.

[0008] The first terminal of the first switching circuit is used to connect to the first terminal of the relay, the second terminal of the first switching circuit is grounded, the first switching circuit is used to turn on the first terminal and the second terminal when the square wave signal is at the first level, and is used to turn off the first terminal and the second terminal when the current flowing through is less than the current threshold.

[0009] The second terminal of the processing circuit is connected to the control terminal of the second switching circuit. The processing circuit is used to send a first turn-on signal to the control terminal of the second switching circuit in response to the turn-on command for the relay when the square wave signal jumps from the first level to the second level.

[0010] The first terminal of the second switching circuit is connected to the DC power supply, the second terminal of the second switching circuit is used to connect to the second terminal of the relay, and the second switching circuit is used to conduct the first terminal and the second terminal of the second switching circuit based on the first conduction signal.

[0011] On the other hand, a relay control method is provided, applied to a processing circuit in a relay control circuit; the control circuit includes: a zero-crossing detection circuit, a first switching circuit, a processing circuit, a second switching circuit, and a DC power supply; the input terminal of the zero-crossing detection circuit is used to receive alternating current; the output terminal of the zero-crossing detection circuit is connected to the control terminal of the first switching circuit and the first terminal of the processing circuit, respectively; the zero-crossing detection circuit is used to output a square wave signal based on the alternating current; the first terminal of the first switching circuit is connected to the first terminal of the relay; the second terminal of the first switching circuit is grounded; the second terminal of the processing circuit is connected to the control terminal of the second switching circuit; the first terminal of the second switching circuit is connected to the DC power supply; and the second terminal of the second switching circuit is connected to the second terminal of the relay; the method includes:

[0012] Receive a turn-on command for the relay;

[0013] In response to the turn-on command, when the square wave signal transitions from the first level to the second level, a first turn-on signal is sent to the control terminal of the second switching circuit.

[0014] In another aspect, a switching device is provided, the switching device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the relay control method as described above.

[0015] In another aspect, a computer-readable storage medium is provided, wherein a computer program is stored therein, the computer program being loaded and executed by a processor to implement the relay control method as described above.

[0016] In another aspect, a computer program product containing instructions is provided, which, when run on the computer, causes the computer to perform the relay control method described above.

[0017] In another aspect, a switching device is provided, the switching device comprising: a relay, and a control circuit for the relay as described above.

[0018] The beneficial effects of the technical solution provided in this application include at least the following:

[0019] This application provides a control circuit, control method, and switching device for a relay. The processing circuit can respond to a conduction command for the relay and control the second switching circuit to conduct, thereby closing the relay. That is, the processing circuit can automatically control the relay to close, thus improving the control flexibility of the relay. Since the processing circuit controls the second switching circuit to conduct and close the relay when the square wave signal output by the zero-crossing detection circuit jumps from the first level to the second level, i.e., at the zero-crossing point of the AC current, it can avoid arcing and sputtering of the relay contacts, thereby extending the service life of the relay.

[0020] Furthermore, since the processing circuit controls the second switching circuit to turn on when the square wave signal transitions from the first level to the second level, and since the first switching circuit turns on when the square wave signal is at the first level, it can be known that the turn-on time of the first switching circuit is later than that of the second switching circuit. Therefore, the relay is turned on under the control of the first switching circuit. Because the switching circuit requires a shorter response time (e.g., at the microsecond level) compared to the processing circuit, using the first switching circuit to control the relay ensures higher control accuracy. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a switching device provided in an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of another switching device provided in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of an alternating current provided in an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of a square wave signal provided in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of a zero-crossing detection circuit provided in an embodiment of this application;

[0027] Figure 6 This is a schematic diagram of the structure of yet another switching device provided in the embodiments of this application;

[0028] Figure 7This is a schematic diagram of another type of switching device provided in an embodiment of this application;

[0029] Figure 8 This is a flowchart of a relay control method provided in an embodiment of this application;

[0030] Figure 9 This is a flowchart of another relay control method provided in the embodiments of this application. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0032] This application provides a switching device, see [link to relevant documentation] Figure 1 The switching device includes a control circuit 10 for a relay and a relay 20. Optionally, the switching device can be a socket, such as a fixed socket or a repositionable socket (i.e., a movable socket).

[0033] See Figure 1 The control circuit 10 includes: a zero-crossing detection circuit 01, a first switching circuit 02, a processing circuit 03, a second switching circuit 04, and a DC power supply 05. The input terminal of the zero-crossing detection circuit 01 is used to receive AC power, and the output terminal of the zero-crossing detection circuit 01 is connected to the control terminal of the first switching circuit 02 and the first terminal of the processing circuit 03, respectively. The zero-crossing detection circuit 01 is used to output a square wave signal based on the AC power.

[0034] The first terminal of the first switching circuit 02 is connected to the first terminal of the relay 20, and the second terminal of the first switching circuit 02 is grounded. This first switching circuit 02 is used to turn on its first and second terminals when the square wave signal output by the zero-crossing detection circuit 01 is at a first level, and to turn off its first and second terminals when the current flowing through it is less than a current threshold. That is, the first switching circuit 02 can turn on after receiving a square wave signal of the first level and turn off when the current flowing through it is less than a current threshold. The current threshold can be 0.01A.

[0035] The second terminal of the processing circuit 03 is connected to the control terminal of the second switching circuit 04. In response to a turn-on command for the relay 20, the processing circuit 03 sends a first turn-on signal to the control terminal of the second switching circuit 04 when the square wave signal output by the zero-crossing detection circuit 01 transitions from a first level to a second level (i.e., at the transition edge of the square wave signal). The moment corresponding to the transition edge of the square wave signal is the zero-crossing point of the alternating current. The switching device can establish a communication connection with a mobile terminal, and the turn-on command can be sent from the mobile terminal to the processing circuit 03 of the switching device. That is, the control circuit provided in this embodiment supports remote control of the relay 20.

[0036] The first terminal of the second switching circuit 04 is connected to the DC power supply 05, and the second terminal of the second switching circuit 04 is used to connect to the second terminal of the relay 20. The second switching circuit 04 is used to turn on the first terminal and the second terminal based on the first conduction signal.

[0037] Understandably, relay 20 also includes a third terminal and a fourth terminal. The third terminal of relay 20 can be used to receive alternating current, and the fourth terminal of relay 20 can be connected to the first terminal of a load (such as a household appliance), the second terminal of which can be grounded. Furthermore, when the first and second terminals of relay 20 are energized, the third and fourth terminals of relay 20 become conductive, thereby enabling the load to operate under the drive of alternating current.

[0038] In this embodiment, when the first and second terminals of the second switching circuit 04 are connected, the square wave signal output by the zero-crossing detection circuit 01 is still at the second level. At this time, the first switching circuit 02 is not yet connected, and correspondingly, the relay 20 cannot be connected either. After the zero-crossing detection circuit 01 outputs a square wave signal at the first level, the first switching circuit 02 can be connected, and a current loop can be formed between the second switching circuit 04, the relay 20, and the first switching circuit 02, thereby enabling the third and fourth terminals of the relay 20 to conduct.

[0039] In summary, this application provides a control circuit for a relay. The processing circuit can respond to a conduction command for the relay and control the second switching circuit to conduct, thereby closing the relay. That is, the processing circuit can automatically control the relay to close, thus improving the control flexibility of the relay. Since the processing circuit controls the second switching circuit to conduct to close the relay when the square wave signal output by the zero-crossing detection circuit jumps from the first level to the second level, i.e., at the zero-crossing point of the AC current, it can avoid arcing and sputtering of the relay contacts, thereby extending the service life of the relay.

[0040] Furthermore, since the processing circuit controls the second switching circuit to turn on when the square wave signal transitions from the first level to the second level, and since the first switching circuit turns on when the square wave signal is at the first level, it can be known that the turn-on time of the first switching circuit is later than that of the second switching circuit. Therefore, the relay is turned on under the control of the first switching circuit. Because the switching circuit requires a shorter response time (e.g., at the microsecond level) compared to the processing circuit, using the first switching circuit to control the relay ensures higher control accuracy.

[0041] Since relay 20 is a switching device that controls a large current operation with a small current, the DC power supply 05 can be a power source that provides low-voltage electricity. For example, DC power supply 05 can be a +5V DC power supply or a +12V DC power supply.

[0042] Optionally, the first level of the square wave signal output by the zero-crossing detection circuit 01 can be high compared to the second level. Correspondingly, the transition from the first level to the second level of the square wave signal is the falling edge of the square wave signal. That is, the processing circuit 03 can control the second switching circuit 04 to turn on when the falling edge of the square wave signal is detected.

[0043] Optionally, the AC power can be mains power (e.g., 220V mains power). Alternatively, the AC power can be current supplied by an AC power source. If the AC power is mains power, the input terminal of the zero-crossing detection circuit 01 can be connected to the live wire and neutral wire of the mains power.

[0044] It is understandable that if the waveform of alternating current is like... Figure 3 The sine wave shown can be used as follows: the zero-crossing detection circuit 01 can output a square wave signal based on the AC current as follows: Figure 4 As shown. Combined with Figure 3 and Figure 4 It can be seen that when the voltage of the sinusoidal alternating current is positive, the level of the square wave signal is 0V.

[0045] In this embodiment, if the processing circuit 03 receives a shutdown command for the relay 20, it can control the first and second terminals of the second switching circuit 04 to disconnect, thereby cutting off the current loop formed between the second switching circuit 04, the relay 20, and the first switching circuit 02, and thus causing the relay 20 to disconnect. The shutdown command can also be sent to the processing circuit 03 by the mobile terminal.

[0046] In one alternative implementation, the processing circuit 03 can directly output a first shutdown signal to the control terminal of the second switching circuit 04 to control the first terminal of the second switching circuit 04 to disconnect from the second terminal.

[0047] In another alternative implementation, see [link to implementation details]. Figure 2The control circuit 10 may further include a third switching circuit 06. Figure 2 It can be seen that the third terminal of the processing circuit 03 is connected to the control terminal of the third switching circuit 06. The processing circuit 03 can also be used to send a second turn-on signal to the control terminal of the third switching circuit 06 in response to the turn-off command for the relay 20, when the square wave signal jumps from the first level to the second level.

[0048] The first terminal of the third switching circuit 06 is connected to the output terminal of the zero-crossing detection circuit 01, and the second terminal of the third switching circuit 06 is connected to the control terminal of the second switching circuit 04. The third switching circuit 06 is used to turn on its first and second terminals based on a second conduction signal, so as to send a square wave signal to the control terminal of the second switching circuit 04. The second switching circuit 04 is also used to disconnect its first and second terminals when the square wave signal is at a first level.

[0049] Thus, when the square wave signal input to the second switching circuit 04 is high, the second switching circuit 04 can turn off its first and second terminals. After the second switching circuit 04 is turned off, the current flowing through the first switching circuit 02 will be less than the current threshold, so the first switching circuit 02 can turn off its first and second terminals. Furthermore, the connection between the third and fourth terminals of the relay 20 can also be disconnected, and the AC power can no longer drive the load.

[0050] Since the processing circuit 03 can control the third switching circuit 06 to turn on so that the relay 20 is turned off when the square wave signal output by the zero-crossing detection circuit 01 jumps from the first level to the second level, the arcing and arcing of the contacts of the relay 20 can be avoided, thereby further extending the service life of the relay 20.

[0051] When the third switching circuit 06 is turned on, the second switching circuit 04 remains on. After the zero-crossing point, the third switching circuit 06 outputs a square wave signal of the first level, and the second switching circuit 04 turns off to disconnect the relay 20. Therefore, the turning off time of the second switching circuit 04 is later than the turning on time of the third switching circuit 06, and thus the relay 20 is turned off under the control of the second switching circuit 04. Since the response time of the switching circuit is shorter than that of the processing circuit 03, using the second switching circuit 04 to control the relay 20 ensures higher control accuracy and a longer service life for the relay.

[0052] It is understandable that after the third switching circuit 06 is turned on, the square wave signal output by the zero-crossing detection circuit 01 can also be used as the control signal for the second switching circuit 04. That is, the square wave signal can be used simultaneously as the control signal for the first switching circuit 02 and the second switching circuit 04. To ensure the effective turn-off of the relay 20, the turn-on condition of the second switching circuit 04 can be set to be opposite to that of the first switching circuit 02. That is, under the same level of square wave signal, only one of the first switching circuit 02 and the second switching circuit 04 can be turned on. For example, if the first switching circuit 02 turns on after receiving a square wave signal of the first level, then the second switching circuit 04 needs to be set to turn on when receiving a square wave signal of the second level and turn off when receiving a square wave signal of the first level. Otherwise, the current loop formed between the second switching circuit 04, the relay 20, and the first switching circuit 02 will enter a "conduction-turn-off" cycle.

[0053] As can be seen from the above description, the control circuit provided in this application embodiment controls the on / off state of the relay 20 through the first switch circuit 02 and the second switch circuit 04: when both the first switch circuit 02 and the second switch circuit 04 are on, the relay 20 can be closed; when the first switch circuit 02 and / or the second switch circuit 04 are off, the relay 20 is open.

[0054] Figure 5 This is a schematic diagram of a zero-crossing detection circuit provided in an embodiment of this application. From... Figure 5 It can be seen that the zero-crossing detection circuit 01 may include: a first diode D1, a first resistor R1, a second diode D2, an optocoupler 011, a second resistor R2, a third resistor R3, and a reference power supply 012.

[0055] Combination Figure 5 and Figure 6 It can be seen that the anode of the first diode D1 is connected to the first terminal of the AC power supply, and the cathode of the first diode D1 is connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is connected to the cathode of the second diode D2 and the first terminal of the optocoupler 011. The anode of the second diode D2 is connected to the second terminal of the optocoupler 011 and is used to connect to the second terminal of the AC power supply. If the AC power supply is AC mains power, then the first terminal of the AC power supply can be the live wire, and the second terminal can be the neutral wire.

[0056] The third terminal of optocoupler 011 is connected to the first terminal of processing circuit 03, the control terminal of first switching circuit 02, and the first terminal of second resistor R2. That is, the third terminal of optocoupler 011 is the output terminal of zero-crossing detection circuit 01. The second terminal of the second resistor R2 is grounded.

[0057] The fourth terminal of optocoupler 011 is connected to the first terminal of the third resistor R3, and the second terminal of the third resistor R3 is connected to the reference power supply.

[0058] Optionally, the first switching circuit 02 can be a thyristor. The second switching circuit 04 can be a transistor. For example, from Figure 6 It can be seen that the second switching circuit 04 can be a transistor. This transistor can be a positive (P) negative (N) type transistor, that is, a PNP type transistor.

[0059] Optionally, the third switching circuit 06 provided in this embodiment can be a load switch or a transistor. For example, the third switching circuit 06 can be a load switch. Figure 6 As can be seen, the load switch 06 may include: an enable (EN) terminal, a ground (GND) terminal, an input (in) voltage (V) terminal, and an output (out) voltage terminal.

[0060] Please continue reading Figure 6 The enable terminal of load switch 06 is connected to the third terminal of processing circuit 03, and the input voltage (i.e. Figure 5 The Vin terminal shown is connected to the output terminal of the zero-crossing detection circuit 01, and the output voltage (i.e. Figure 5 The Vout terminal shown can be connected to the control terminal of the second switch circuit 04, and the ground (GND) terminal is grounded.

[0061] Figure 7 This is a schematic diagram of another switching device provided in an embodiment of this application. See also... Figure 7 The control circuit may further include a current-limiting resistor 07. The first end of the current-limiting resistor 07 is connected to the control terminal of the second switching circuit 04, and the second end of the current-limiting resistor 07 is connected to the second terminal of the processing circuit 03 and the second terminal of the third switching circuit 06, respectively.

[0062] The embodiments of this application are as follows: Figure 6 The control circuit shown here, with the first level being high relative to the second level, AC power being the mains power, and the relay initially being in the open state, serves as an example to illustrate the working principle of the control circuit provided in this application embodiment:

[0063] After the mains power passes through the zero-crossing detection circuit 01, the zero-crossing detection circuit 01 can output... Figure 4 The square wave signal S1 shown can be transmitted to the control terminal of thyristor 02 as a control signal for thyristor 02, and can also be transmitted to the first terminal of processing circuit 03 as an input signal for processing circuit 03.

[0064] Since thyristor 02 can be turned off when the current flowing through it is less than the current threshold, it cannot be turned on even if it receives a square wave signal of the first level (i.e., high level) before transistor 04 is turned on.

[0065] After relay 20 is disconnected, if processing circuit 03 receives a turn-on command for relay 20, it can continuously output a low-level first turn-on signal S2 to the control terminal (base) of the second switching circuit 04 at the falling edge of square wave signal S1 when it detects that square wave signal S1 has transitioned from the first level to the second level (i.e., low level). Upon receiving this first turn-on signal S2, the second switching circuit 04 can turn on. After square wave signal S1 transitions from low level to high level, the gate of thyristor 02 receives a positive trigger voltage, and a positive voltage exists between the anode and cathode of thyristor 02. At this time, thyristor 02 can turn on. After thyristor 02 turns on, a current loop can be formed between DC power supply 05, transistor 04, relay 20, and thyristor 02. Correspondingly, relay 20 can close. Due to the characteristics of thyristor 02, once the anode and cathode are turned on, even if the voltage received at the gate becomes 0, the conduction state of thyristor 02 will not change.

[0066] If the processing circuit 03 receives a turn-off command for the relay 20, it can output a second turn-on signal S3 to the enable terminal of the load switch 06 on the falling edge of the square wave signal, thereby turning on the load switch 06. After the load switch 06 is turned on, the signal output from the second terminal (i.e., the Vout terminal) of the load switch 06 is the square wave signal S1. That is, the square wave signal S1 can be input to the control terminal of the transistor 04 through the current-limiting resistor 07.

[0067] When the level of the square wave signal S1 transitions from low to high, transistor 04 is turned off. Correspondingly, the current loop formed between DC power supply 05, transistor 04, relay 20, and thyristor 02 is cut off, thyristor 02 is turned off, and relay 20 is disconnected. Afterwards, processing circuit 03 can control load switch 06 to turn off.

[0068] In summary, this application provides a control circuit for a relay. The processing circuit can respond to a conduction command for the relay and control the second switching circuit to conduct, thereby closing the relay. That is, the processing circuit can automatically control the relay to close, thus improving the control flexibility of the relay. Since the processing circuit controls the second switching circuit to conduct to close the relay when the square wave signal output by the zero-crossing detection circuit jumps from the first level to the second level, i.e., at the zero-crossing point of the AC current, it can avoid arcing and sputtering of the relay contacts, thereby extending the service life of the relay.

[0069] Furthermore, since the processing circuit controls the second switching circuit to turn on when the square wave signal transitions from the first level to the second level, and since the first switching circuit turns on when the square wave signal is at the first level, it can be known that the turn-on time of the first switching circuit is later than that of the second switching circuit. Therefore, the relay is turned on under the control of the first switching circuit. Because the switching circuit requires a shorter response time (e.g., at the microsecond level) compared to the processing circuit, using the first switching circuit to control the relay ensures higher control accuracy.

[0070] This application provides a relay control method, which is applied to the processing circuit in the relay control circuit, for example... Figure 1 , Figure 2 , Figure 6 and Figure 7 Any of the control circuits shown. See also Figure 8 The method includes:

[0071] Step 301: Receive the turn-on command for the relay.

[0072] In this embodiment, the switching device can establish a communication connection with a mobile terminal. The activation command for the relay can be sent from the mobile terminal to the processing circuit of the switching device.

[0073] Step 302: In response to the turn-on command, when the square wave signal changes from the first level to the second level, a first turn-on signal is sent to the control terminal of the second switching circuit.

[0074] After receiving a conduction command for the relay, the processing circuit can respond to the command by sending a first conduction signal to the control terminal of the second switching circuit at the transition edge of the square wave signal, which occurs when the square wave signal transitions from the first level to the second level. Upon receiving the first conduction signal, the second switching circuit can control its first and second terminals to conduct, thereby forming a current loop between the second switching circuit, the relay, and the first switching circuit after the square wave signal transitions from the second level to the first level, which in turn causes the relay to close.

[0075] In summary, this application provides a relay control method. The processing circuit can respond to a relay activation command and control the second switching circuit to activate, thereby closing the relay. That is, the processing circuit can automatically control the relay to close, thus improving the relay control flexibility. Since the processing circuit controls the second switching circuit to activate and close the relay when the square wave signal output by the zero-crossing detection circuit transitions from the first level to the second level (i.e., at the zero-crossing point of the AC current), arcing and sputtering of the relay contacts can be avoided, thereby extending the relay's service life.

[0076] Furthermore, since the processing circuit controls the second switching circuit to turn on when the square wave signal transitions from the first level to the second level, and since the first switching circuit turns on when the square wave signal is at the first level, it can be known that the turn-on time of the first switching circuit is later than that of the second switching circuit. Therefore, the relay is turned on under the control of the first switching circuit. Because the switching circuit requires a shorter response time (e.g., at the microsecond level) compared to the processing circuit, using the first switching circuit to control the relay ensures higher control accuracy.

[0077] Figure 9 This is a flowchart of another relay control method provided in an embodiment of this application. This method can be applied to the processing circuit in the relay control circuit, for example... Figure 1 , Figure 2 , Figure 6 and Figure 7 Any of the control circuits shown. See also Figure 9 The method includes

[0078] Step 401: Receive the turn-on command for the relay.

[0079] In this embodiment, the switching device can establish a communication connection with a mobile terminal, and the switching device includes a control circuit for a relay. The activation command for the relay can be sent from the mobile terminal to the processing circuit in the control circuit.

[0080] Step 402: In response to the turn-on command, when the square wave signal changes from the first level to the second level, a first turn-on signal is sent to the control terminal of the second switching circuit.

[0081] Specifically, the transition edge of the square wave signal occurs when it transitions from the first level to the second level. After receiving the first conduction signal, the second switching circuit can control its first and second terminals to conduct, thereby enabling a current loop to be formed between the second switching circuit, the relay, and the first switching circuit after the square wave signal transitions from the second level to the first level, which in turn allows the relay to close.

[0082] Step 403: Receive the shutdown command for the relay.

[0083] The shutdown command can be sent by a mobile terminal that has established a communication connection with the switching device.

[0084] Step 404: In response to the shutdown command, when the square wave signal changes from the first level to the second level, a second turn-on signal is sent to the control terminal of the third switching circuit.

[0085] After receiving the square wave signal, the third switching circuit can connect its first and second terminals. In this way, the output of the second switching circuit can send a square wave signal to its control terminal. The second switching circuit is also used to disconnect its first and second terminals when the square wave signal is at a first level.

[0086] Thus, when the square wave signal input to the second switching circuit is high, the second switching circuit can turn off its first and second terminals. After the second switching circuit is turned off, the current flowing through the first switching circuit will be less than the current threshold, so the first switching circuit can also turn off its first and second terminals. Furthermore, the connection between the third and fourth terminals of the relay can also be broken, and the AC power can no longer drive the load.

[0087] It is understood that the order of steps in the relay control method provided in this application embodiment can be appropriately adjusted, and steps can be added or removed as needed. For example, steps 403 and 404 can also be deleted as needed. Any variations that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application, and therefore will not be elaborated further.

[0088] In summary, this application provides a relay control method. The processing circuit can respond to a relay activation command and control the second switching circuit to activate, thereby closing the relay. That is, the processing circuit can automatically control the relay to close, thus improving the relay control flexibility. Since the processing circuit controls the second switching circuit to activate and close the relay when the square wave signal output by the zero-crossing detection circuit transitions from the first level to the second level (i.e., at the zero-crossing point of the AC current), arcing and sputtering of the relay contacts can be avoided, thereby extending the relay's service life.

[0089] Furthermore, since the processing circuit controls the second switching circuit to turn on when the square wave signal transitions from the first level to the second level, and since the first switching circuit turns on when the square wave signal is at the first level, it can be known that the turn-on time of the first switching circuit is later than that of the second switching circuit. Therefore, the relay is turned on under the control of the first switching circuit. Because the switching circuit requires a shorter response time (e.g., at the microsecond level) compared to the processing circuit, using the first switching circuit to control the relay ensures higher control accuracy.

[0090] This application provides a switching device. The mobile terminal may include a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the relay control method provided in the above embodiments, for example... Figure 8 or Figure 9 The method shown.

[0091] This application provides a computer-readable storage medium storing a computer program, which is loaded and executed by a processor using the relay control method provided in the above embodiments, for example... Figure 8 or Figure 9 The method shown.

[0092] This application also provides a computer program product containing instructions that, when run on a computer, cause the computer to execute the relay control method provided in the above-described method embodiments, for example... Figure 8 or Figure 9 The method shown.

[0093] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0094] It should be understood that the term "and / or" as used herein indicates that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. Furthermore, the term "at least one" in this application means one or more, and the term "multiple" in this application means two or more.

[0095] In this application, the terms "first," "second," etc., are used to distinguish identical or similar items that have essentially the same function. It should be understood that there is no logical or temporal dependency between "first," "second," and "nth," nor is there any limitation on the quantity or execution order. For example, without departing from the scope of the various examples described, a first conducting signal can be referred to as a second conducting signal, and similarly, a second conducting signal can be referred to as a first conducting signal.

[0096] The above description is merely an exemplary embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A control circuit for a relay, characterized in that, The control circuit includes: a zero-crossing detection circuit, a first switching circuit, a processing circuit, a second switching circuit, and a DC power supply; The input terminal of the zero-crossing detection circuit is used to receive AC power, and the output terminal of the zero-crossing detection circuit is connected to the control terminal of the first switching circuit and the first terminal of the processing circuit, respectively. The zero-crossing detection circuit is used to output a square wave signal based on the AC power. The first terminal of the first switching circuit is used to connect to the first terminal of the relay, the second terminal of the first switching circuit is grounded, the first switching circuit is used to turn on the first terminal and the second terminal when the square wave signal is at the first level, and is used to turn off the first terminal and the second terminal when the current flowing through is less than the current threshold. The second terminal of the processing circuit is connected to the control terminal of the second switching circuit. The processing circuit is used to send a first turn-on signal to the control terminal of the second switching circuit in response to the turn-on command for the relay when the square wave signal jumps from the first level to the second level. The first terminal of the second switching circuit is connected to the DC power supply, the second terminal of the second switching circuit is used to connect to the second terminal of the relay, and the second switching circuit is used to conduct the first terminal and the second terminal of the second switching circuit based on the first conduction signal.

2. The control circuit according to claim 1, characterized in that, The control circuit also includes: a third switching circuit; The third terminal of the processing circuit is connected to the control terminal of the third switching circuit. The processing circuit is also used to send a second turn-on signal to the control terminal of the third switching circuit in response to the turn-off command for the relay when the square wave signal jumps from the first level to the second level. The first terminal of the third switching circuit is connected to the output terminal of the zero-crossing detection circuit, and the second terminal of the third switch is connected to the control terminal of the second switching circuit. The third switching circuit is used to conduct the first terminal and the second terminal of the third switching circuit based on the second conduction signal to send the square wave signal to the control terminal of the second switching circuit. The second switching circuit is also used to disconnect the first terminal and the second terminal of the second switching circuit when the square wave signal is at the first level.

3. The control circuit according to claim 2, characterized in that, The third switching circuit is a load switch.

4. The control circuit according to claim 2, characterized in that, The first level is high relative to the second level.

5. The control circuit according to any one of claims 1 to 4, characterized in that, The first switching circuit is a thyristor, and the second switching circuit is a transistor.

6. The control circuit according to claim 5, characterized in that, The transistor is a triode.

7. The control circuit according to any one of claims 1 to 4, characterized in that, The zero-crossing detection circuit includes: a first diode, a first resistor, a second diode, an optocoupler, a second resistor, a third resistor, and a reference power supply; The positive terminal of the first diode is connected to the first terminal of the alternating current, and the negative terminal of the first diode is connected to the first end of the first resistor. The second terminal of the first resistor is connected to the negative terminal of the second diode and the first terminal of the optocoupler, respectively. The positive terminal of the second diode is connected to the second terminal of the optocoupler and is used to connect to the second terminal of the AC power supply; The third terminal of the optocoupler is connected to the first terminal of the processing circuit, the control terminal of the first switching circuit, and the first terminal of the second resistor, respectively. The fourth terminal of the optocoupler is connected to the first terminal of the third resistor, and the second terminal of the third resistor is connected to the reference power supply.

8. A method for controlling a relay, characterized in that, The processing circuit is applied to the control circuit as described in any one of claims 1 to 7; the method includes: Receive a turn-on command for the relay; In response to the conduction command, when the square wave signal transitions from the first level to the second level, a first conduction signal is sent to the control terminal of the second switching circuit in the control circuit.

9. The method according to claim 8, characterized in that, The method further includes: Receive a shutdown command for the relay; In response to the shutdown command, when the square wave signal transitions from the first level to the second level, a second turn-on signal is sent to the control terminal of the third switching circuit in the control circuit.

10. A switching device, characterized in that, The switching device includes: a relay, and a control circuit for the relay as described in any one of claims 1 to 7.

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