Control circuit based on single switch and electronic equipment

Abstract

The utility model discloses a control circuit based on a single switch and electronic equipment. The switch is connected between an alternating current power supply and the control circuit, and the control circuit comprises a rectification branch, a clamping branch, a one-way conductive branch, an energy storage branch and a controller. The rectification branch is configured to rectify an alternating current power supply into a direct current power supply and input the direct current power supply to a first node. The clamp branch is configured to clamp a voltage of the first node. The controller is configured to determine whether the switch is turned off based on a voltage of the first node. The unidirectional conductive branch is configured to be conducted in response to the voltage of the first node being greater than the voltage of the second node, to supply power to the controller based on the voltage of the second node, and to be cut off when the voltage of the second node is greater than the voltage of the first node. The energy storage branch is configured to store electric energy when the one-way conductive branch is switched on and release the electric energy when the one-way conductive branch is switched off. In this way, a low-cost mode for detecting the disconnection of the switch can be provided.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of electronic circuits, and in particular to a control circuit and electronic equipment based on a single switch. Background Art

[0002] At present, in electronic devices, in order to save costs, sometimes a single device needs to be able to realize multiple functions. In some electronic devices, it is necessary to perform different operations on the switch connected between the AC power supply and the power-consuming device in the electronic device to realize different functions. For example, the switch only performs the closing operation and the switch performs the closing, opening, and closing operations within a preset time. These two operations correspond to different functions.

[0003] Among them, for the solution that the switch performs the operation of closing, opening, and closing within a preset time, since the connection between the AC power supply and the power device is disconnected when the switch is opened, the controller in the power device will also lose power, which may cause the controller to be unable to detect the operation of the switch being opened. Therefore, the existing practice is to turn on other power supplies to power the controller when the switch is opened to ensure that the operation of the switch being opened can be detected. However, the cost of this method is relatively high. Utility Model Content

[0004] The embodiments of the present application provide a control circuit and an electronic device based on a single switch, which can provide a low-cost method for detecting switch disconnection.

[0005] In a first aspect, an embodiment of the present application provides a control circuit based on a single switch, wherein the switch is connected between an AC power source and the control circuit, wherein the control circuit includes a rectifying branch, a clamping branch, a unidirectional conductive branch, an energy storage branch, and a controller;

[0006] The switch is connected between the AC power source and the rectifying branch, the rectifying branch, the clamping branch, the unidirectional conductive branch and the controller are connected to a first node, and the unidirectional conductive branch, the energy storage branch and the controller are connected to a second node;

[0007] The rectifying branch is configured to rectify the AC power supply into a DC power supply and input the DC power supply to the first node;

[0008] The clamping branch is configured to clamp the voltage of the first node;

[0009] The controller is configured to determine whether the switch is open based on the voltage of the first node;

[0010] The unidirectional conductive branch is configured to be turned on in response to the voltage of the first node being greater than the voltage of the second node, so as to power the controller based on the voltage of the second node, and to be turned off when the voltage of the second node is greater than the voltage of the first node;

[0011] The energy storage branch is configured to store electric energy when the unidirectional conductive branch is turned on, and release electric energy when the unidirectional conductive branch is turned off.

[0012] In one or more embodiments, the control circuit further includes a protection branch and a voltage reduction branch, and the switch is connected to the rectification branch through the protection branch and the voltage reduction branch in sequence;

[0013] The protection branch is configured to limit current and filter the AC power supply and implement overvoltage protection;

[0014] The step-down branch is configured to generate a capacitive reactance to step down the AC power supply and then input the AC power supply into the rectifying branch, and the AC power supply is rectified into the DC power supply by the rectifying branch.

[0015] In one or more embodiments, the control circuit further comprises a switch branch, wherein the switch branch is connected between the rectifier branch and the first node, the switch branch is connected between the switch and the load, and the switch branch is also connected to the controller;

[0016] The switch branch is configured to disconnect the switch from the load in response to a first control signal output by the controller, so that the AC power source stops supplying power to the load;

[0017] The switch branch is further configured to conduct the connection between the switch and the load in response to a second control signal output by the controller, so that the AC power source supplies power to the load.

[0018] In one or more embodiments, the clamping branch includes a first zener diode;

[0019] An anode of the first Zener diode is grounded, and a cathode of the first Zener diode is connected to the first node.

[0020] In one or more embodiments, the unidirectional conductive branch includes a first diode;

[0021] An anode of the first diode is connected to the first node, and a cathode of the first diode is connected to the second node.

[0022] In one or more embodiments, the energy storage branch includes a first capacitor;

[0023] The first capacitor is connected between the second node and ground.

[0024] In one or more embodiments, the protection branch includes a first resistor, a second resistor, a varistor and a second capacitor;

[0025] The first resistor and the second resistor are connected in series between the switch and the step-down branch, the varistor is connected between a connection point between the first resistor and the second resistor and ground, and the second capacitor is connected in parallel with the varistor.

[0026] In one or more embodiments, the voltage-reducing branch includes a third resistor and a third capacitor;

[0027] The third resistor and the third capacitor are connected in parallel between the protection branch and the rectification branch.

[0028] In one or more embodiments, the switch branch includes a first switch tube, a second switch tube, a fourth resistor, a fifth resistor, a sixth resistor, a fourth capacitor, a fifth capacitor, a second voltage regulator diode and a relay;

[0029] The first end of the first switch tube is connected to the controller through the fourth resistor, the first end of the first switch tube is also grounded through the fourth capacitor, the second end of the first switch tube is grounded, the third end of the first switch tube is connected to the first end of the second switch tube through the fifth resistor, the second end of the second switch tube is connected to the rectifier branch, the third end of the second switch tube is connected to the first node through the sixth resistor, the fifth capacitor is connected between the second end of the second switch tube and the first node, the anode of the second Zener diode is connected to the first node, the cathode of the second Zener diode is connected to the second end of the second switch tube, the coil of the relay is connected between the second end of the second switch tube and the first node, one of a pair of normally open contacts of the relay is connected to the switch, and the other contact is connected to the load.

[0030] In a second aspect, an embodiment of the present application provides an electronic device, including a switch and a control circuit based on a single switch as described above, wherein the switch is connected between an AC power source and the control circuit.

[0031] The beneficial effects of the present application are as follows: the control circuit based on a single switch of the embodiment of the present application includes a rectifier branch, a clamping branch, a unidirectional conductive branch, an energy storage branch and a controller. The switch is connected between the AC power supply and the rectifier branch, the rectifier branch, the clamping branch, the unidirectional conductive branch and the controller are connected to the first node, and the unidirectional conductive branch, the energy storage branch and the controller are connected to the second node. The rectifier branch is configured to rectify the AC power supply into a DC power supply and input it to the first node. The clamping branch is configured to clamp the voltage of the first node. The controller is configured to determine whether the switch is disconnected based on the voltage of the first node. The unidirectional conductive branch is configured to be turned on in response to the voltage of the first node being greater than the voltage of the second node, to power the controller based on the voltage of the second node, and to be turned off when the voltage of the second node is greater than the voltage of the first node. The energy storage branch is configured to store electrical energy when the unidirectional conductive branch is turned on, and to release electrical energy when the unidirectional conductive branch is turned off. Then, when the switch is disconnected, the voltage of the first node N1 will quickly drop to zero, while the voltage of the second node N2 will decrease slowly due to the energy storage function of the energy storage branch, and on the other hand, the unidirectional conductive branch prevents the voltage of the second node N2 from discharging to the first node N1, so as to further slow down the decrease of the voltage of the second node N2, so as to maintain the normal operation of the controller, and then the controller can determine that the switch is disconnected through the voltage of the first node N1. Compared with the related art, the present application does not need to add an additional power supply to power the controller, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] One or more embodiments are exemplarily described by the figures in the accompanying drawings, which are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0033] Figure 1 This is a schematic diagram of the structure of a control circuit based on a single switch provided in an embodiment of the present application. Figure 1 ;

[0034] Figure 2 This is a schematic diagram of the structure of a control circuit based on a single switch provided in an embodiment of the present application. Figure 2 ;

[0035] Figure 3 This is a schematic diagram of the structure of a control circuit based on a single switch provided in an embodiment of the present application. Figure 3 ;

[0036] Figure 4 is with Figure 3 A schematic diagram of a circuit structure corresponding to the structure shown;

[0037] Figure 5 It is a schematic diagram of the voltages of the second node and the third node provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0039] It should be noted that, when an element is described as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.

[0040] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.

[0041] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a control circuit based on a single switch provided in an embodiment of the present application. Figure 1 As shown, the switch K1 is connected between the AC power supply 200 and the control circuit 100. The switch K1 is a device that controls the connection and disconnection between the AC power supply 200 and the control circuit 100 by manual or automatic operation. In some specific embodiments, the switch K1 can be a rocker switch, a button switch, a key switch, etc. In some specific embodiments, the AC power supply 200 can be a mains power supply.

[0042] The control circuit 100 includes a rectifying branch 10, a clamping branch 20, a unidirectional conductive branch 30, an energy storage branch 40 and a controller 50. The switch K1 is connected between the AC power source 200 and the rectifying branch 10, the rectifying branch 10, the clamping branch 20, the unidirectional conductive branch 30 and the controller 50 are connected to a first node N1, and the unidirectional conductive branch 30, the energy storage branch 40 and the controller 50 are connected to a second node N2.

[0043] Specifically, the rectifying branch 10 is configured to rectify the AC power supply 200 into a DC power supply and input it to the first node N1. The clamping branch 20 is configured to clamp the voltage of the first node N1. The controller 50 is configured to determine whether the switch K1 is disconnected based on the voltage of the first node N1. The unidirectional conductive branch 30 is configured to be turned on in response to the voltage of the first node N1 being greater than the voltage of the second node N2, so as to power the controller 50 based on the voltage of the second node N2, and to be turned off when the voltage of the second node N2 is greater than the voltage of the first node N1. The energy storage branch 40 is configured to store electrical energy when the unidirectional conductive branch 30 is turned on, and to release electrical energy when the unidirectional conductive branch 30 is turned off.

[0044] In practical applications, when the switch K1 is closed, the AC power supply 200 is rectified into a DC power supply by the rectifying branch 10 and input to the first node N1. Then, the voltage of the first node N1 is clamped by the clamping branch 20. At the same time, since the voltage of the first node N1 and the voltage of the second node N2 (which is zero at this time) are equal, the unidirectional conductive branch 30 is turned on, and the voltage of the first node N1 acts on the second node N2 through the unidirectional conductive branch 30. On the one hand, the voltage of the second node N2 supplies power to the controller 50; on the other hand, the energy storage branch 40 stores electrical energy in response to the voltage of the second node N2.

[0045] When the switch K1 is disconnected, the voltage of the first node N1 is rapidly reduced to zero. At this time, since the electric energy stored in the energy storage branch 40 makes the voltage of the second node N2 decrease slower than the voltage of the first node N1, the voltage of the second node N2 is greater than the voltage of the first node N1. Then, the unidirectional conductive branch 30 is cut off to prevent the voltage of the second node N2 from discharging through the unidirectional conductive branch 30, further slowing down the speed of the voltage reduction of the second node N2. Moreover, before the voltage of the second node N2 is reduced to the minimum power supply voltage of the controller 50, the controller 50 can still keep running. It can be seen that the controller 50 can keep running for a period of time after the switch K1 is disconnected. The voltage of the first node N1 is rapidly reduced to zero. Thus, the controller 50 can detect that the voltage of the first node N1 is reduced to zero during the time period when the switch K1 is disconnected and keeps running, and then determine that the switch K1 is disconnected. Compared with the solution in the related art that needs to turn on other power supplies to power the controller when the switch is disconnected to detect whether the switch is disconnected, the present application does not need to add additional power supplies, and the cost is low.

[0046] In one embodiment, if Figure 2 As shown, the control circuit 100 further includes a protection branch 60 and a voltage reduction branch 70 , and the switch K1 is connected to the rectification branch 10 via the protection branch 60 and the voltage reduction branch 70 in sequence.

[0047] The protection branch 60 is configured to limit the current and filter the AC power supply 200, and to achieve overvoltage protection. By limiting the current and filtering the AC power supply 200, the voltage or current input to the subsequent circuit can be prevented from being too large and damaging the components in the subsequent circuit, so as to protect the components in the subsequent circuit. The step-down branch 70 is configured to generate a capacitive reactance to reduce the AC power supply 200 and input it into the rectifier branch 10, and the rectifier branch 10 rectifies it into a DC power supply. The magnitude of the reduction of the AC power supply 200 is determined by the magnitude of the capacitive reactance. The larger the capacitive reactance, the greater the magnitude of the reduction of the AC power supply 200; the smaller the capacitive reactance, the smaller the magnitude of the reduction of the AC power supply 200. By stepping down the AC power supply 200, a voltage suitable for powering the components in the subsequent circuit (such as the controller 50) can be obtained.

[0048] In one embodiment, if Figure 3 As shown, the control circuit 100 further includes a switch branch 80 . The switch branch 80 is connected between the rectifier branch 10 and the first node N1 , between the switch K1 and the load 300 , and is also connected to the controller 50 .

[0049] Specifically, the switch branch 80 is configured to disconnect the switch K1 and the load 300 in response to a first control signal output by the controller 50, so that the AC power source 200 stops supplying power to the load 300. The switch branch 80 is also configured to connect the switch K1 and the load 300 in response to a second control signal output by the controller 50, so that the AC power source 200 supplies power to the load 300.

[0050] In a specific embodiment, the first control signal and the second control signal are signals of different levels. For example, the first control signal is a high level signal, and the second control signal is a low level signal.

[0051] Please refer to Figure 4 , Figure 4 The embodiments of the present application provide Figure 3 The structure shown corresponds to a circuit. This embodiment takes the live wire of the AC power source 200 connected to the switch K1 as an example.

[0052] like Figure 4 As shown, the rectifier branch 10 includes a rectifier bridge U1.

[0053] The first end of the rectifier bridge U1 is connected to the switch K1 through the step-down branch 70 and the protection branch 60, the second end of the rectifier bridge U1 is connected to the neutral line of the AC power source 200, the third end of the rectifier bridge U1 is connected to the first node N1 through the switch branch 80, and the fourth end of the rectifier bridge U1 is grounded GND. The rectifier bridge U1 is used to achieve full-wave rectification.

[0054] In this embodiment, the clamping branch 20 includes a first zener diode DW1 .

[0055] The anode of the first Zener diode DW1 is connected to the ground GND, and the cathode of the first Zener diode DW1 is connected to the first node N1.

[0056] When the AC power source 200 is input to the first node N1 through the protection branch 60, the step-down branch 70, the rectifier branch 10 and the switch branch 80, the first voltage stabilizing diode DW1 is reversely broken down, and the reverse resistance of the first voltage stabilizing diode DW1 suddenly drops to a very small value. At this time, although the current changes in a large range, the voltage across the first voltage stabilizing diode DW1 is basically stable near its breakdown voltage, thereby realizing the voltage stabilizing function of the first voltage stabilizing diode DW1.

[0057] In this embodiment, the unidirectional conductive branch 30 includes a first diode D1 .

[0058] The anode of the first diode D1 is connected to the first node N1, and the cathode of the first diode D1 is connected to the second node D2.

[0059] When the voltage of the first node N1 is greater than the voltage of the second node N2, the first diode D1 is forward-conducted; when the voltage of the first node N1 is less than the voltage of the second node N2, the first diode D1 is reverse-cut off.

[0060] In this embodiment, the energy storage branch 40 includes a first capacitor C1.

[0061] The first capacitor C1 is connected between the second node N2 and the ground GND.

[0062] When the first diode D1 is forward-conducted, the voltage of the first node N1 charges the first capacitor C1 through the first diode D1, thereby storing electrical energy; when the first diode D1 is reverse-conducted, the first capacitor C1 is discharged, thereby releasing electrical energy.

[0063] In this embodiment, the protection branch 60 includes a first resistor R1, a second resistor R2, a varistor ZNR and a second capacitor C2.

[0064] The first resistor R1 and the second resistor R2 are connected in series between the switch K1 and the step-down branch 70 , the varistor ZNR is connected between the connection point between the first resistor R1 and the second resistor R2 and the ground GND, and the second capacitor C2 is connected in parallel with the varistor ZNR.

[0065] The first resistor R1 is used for current limiting, the varistor ZNR is used for overvoltage protection, and the second resistor R2 and the second capacitor C2 are used for RC filtering.

[0066] In this embodiment, the voltage-reducing branch 70 includes a third resistor R3 and a third capacitor C3.

[0067] The third resistor R3 and the third capacitor C3 are connected in parallel between the protection branch 60 and the rectification branch 10. The third capacitor C3 can generate capacitive reactance under the action of the AC power supply 200 to limit the maximum working current, thereby achieving the effect of reducing the voltage of the AC power supply 200. The third resistor R3 is a discharge resistor of the third capacitor C3.

[0068] In this embodiment, the switch branch includes a first switch tube Q1, a second switch tube Q2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a fourth capacitor C4, a fifth capacitor C5, a second Zener diode DW2 and a relay U2.

[0069] Among them, the first end of the first switch tube Q1 is connected to the controller 50 through the fourth resistor R4, the first end of the first switch tube Q1 is also grounded to GND through the fourth capacitor C4, the second end of the first switch tube Q1 is grounded to GND, the third end of the first switch tube Q1 is connected to the first end of the second switch tube Q2 through the fifth resistor R5, the second end of the second switch tube Q2 is connected to the rectifier branch 10, the third end of the second switch tube Q2 is connected to the first node N1 through the sixth resistor R6, the fifth capacitor C5 is connected between the second end of the second switch tube Q2 and the first node N1, the anode of the second Zener diode DW2 is connected to the first node N1, the cathode of the second Zener diode DW2 is connected to the second end of the second switch tube Q2, the coil KM1 of the relay U2 is connected between the second end of the second switch tube Q2 and the first node N1, one of the pair of normally open contacts S1 of the relay U2 is connected to the switch K1, and the other contact is connected to the load 300.

[0070] When the controller 50 outputs the first control signal (a high level signal in this embodiment), the first switch tube Q1 is turned on. The base of the second switch tube Q2 is grounded through the first switch tube Q1, and the second switch tube Q2 is turned on. The current of the DC power supply output by the rectifier branch 10 flows through the second switch tube Q2 and the sixth resistor R6. Then, there is no voltage difference between the two ends of the coil KM1, and the coil KM1 is not powered. A pair of normally open contacts S1 remain disconnected, and the AC power supply 200 cannot power the load 300.

[0071] When the controller 50 outputs the second control signal (a low level signal in this embodiment), the first switch tube Q1 is turned off. The second switch tube Q2 is also turned off. The DC power supply acts on the second voltage stabilizing diode DW2, so that the second voltage stabilizing diode DW2 is reversely broken down, and the voltage across the coil KM1 is clamped to the breakdown voltage of the second voltage stabilizing diode DW2. The coil KM1 is energized, a pair of normally open contacts S1 is closed, and the AC power supply 200 supplies power to the load 300 through the switch K1 and the pair of normally open contacts S1.

[0072] In this embodiment, the first switch tube Q1 is an NPN transistor, and the second switch tube Q2 is a PNP transistor. The base of the NPN transistor is the first end of the first switch tube Q1, the emitter of the NPN transistor is the second end of the first switch tube Q1, and the collector of the NPN transistor is the third end of the first switch tube Q1. The base of the PNP transistor is the first end of the second switch tube Q2, the emitter of the PNP transistor is the second end of the second switch tube Q2, and the collector of the PNP transistor is the third end of the second switch tube Q2.

[0073] In addition, the first switch tube Q1 and the second switch tube Q2 can be any controllable switches, such as insulated gate bipolar transistor (IGBT) devices, integrated gate commutated thyristor (IGCT) devices, gate turn-off thyristor (GTO) devices, silicon controlled rectifier (SCR) devices, junction gate field effect transistor (JFET) devices, MOS controlled thyristor (MCT) devices, etc.

[0074] In this embodiment, the control circuit 100 further includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a sixth capacitor C6, a seventh capacitor C7 and an eighth capacitor C8.

[0075] The seventh resistor R7 and the sixth capacitor C6 are connected in series between the neutral line of the AC power source 200 and the load 300, and the seventh resistor R7 and the sixth capacitor C6 form an RC filter. The eighth resistor R8 and the seventh capacitor C7 are connected in series between the first node N1 and the ground GND, and the connection point between the eighth resistor R8 and the seventh capacitor C7 (recorded as the third node N3) is connected to the controller 50, and the eighth resistor R8 and the seventh capacitor C7 form an RC filter. The ninth resistor R9 and the eighth capacitor C8 are connected in parallel between the second node N2 and the ground GND, and the ninth resistor R9 and the eighth capacitor C8 form an RC filter.

[0076] Please refer to Figure 4 and Figure 5 , Figure 5 The voltages of the second node N2 and the third node N3 are exemplarily shown. Figure 5 In FIG. 1 , the abscissa represents time, the ordinate represents voltage, a curve LN2 represents the voltage of the second node N2, and a curve LN3 represents the voltage of the third node N3.

[0077] exist Figure 4 In the embodiment shown, when the switch K1 is closed, the AC power supply 200 becomes a DC power supply after passing through the protection branch 60, the step-down branch 70 and the rectifier branch 10, and the DC power supply is input to the first node N1 through the loop where the second switch tube Q2 and the sixth resistor R6 are located (when the controller 50 outputs the first control signal) or the loop where the second voltage stabilizing diode DW2 is located (when the controller 50 outputs the second control signal). Then, the voltage of the first node N1 is clamped by the first voltage stabilizing diode DW1. At the same time, due to the voltage of the first node N1 and the voltage of the second node N2 (which is zero at this time), the first diode D1 is forward-conducted, and the voltage of the first node N1 acts on the second node N2 through the first diode D1. On the one hand, the voltage of the second node N2 supplies power to the controller 50; on the other hand, the first capacitor C1 stores electrical energy in response to the voltage of the second node N2.

[0078] When the switch K1 is disconnected, the voltage of the first node N1 is rapidly reduced to zero, that is, the voltage of the third node N3 is also rapidly reduced to zero. At this time, since the electric energy stored in the first capacitor C1 makes the voltage of the second node N2 decrease slower than the voltage of the first node N1, the voltage of the second node N2 is greater than the voltage of the first node N1. Then, the first diode D1 is reversely cut off to prevent the voltage of the second node N2 from discharging through the first diode D1, further slowing down the speed of the voltage reduction of the second node N2. At the same time, in some embodiments, the capacitance value of the first capacitor C1 can be increased to further slow down the speed of the voltage reduction of the second node N2. And, before the voltage of the second node N2 is reduced to the minimum power supply voltage of the controller 50, the controller 50 can still keep running.

[0079] like Figure 5 As shown, at time t1, the switch K1 is disconnected, and the voltage of the first node N1 drops rapidly to zero (i.e., drops to zero at time t2), that is, the voltage of the third node N3 also drops to zero at time t2. The voltage of the second node N2 drops slowly. Assuming that at time t3, the voltage of the second node N2 drops to the minimum power supply voltage of the controller 50, the controller 50 stops running. Therefore, in the time period from time t1 to time t3, the controller 50 has sufficient time to determine whether the voltage of the third node N3 drops to zero, and then determine whether the switch K1 is disconnected. Compared with the solution in the related art that needs to turn on other power supplies to power the controller 50 when the switch is disconnected to detect whether the switch K1 is disconnected, the present application does not need to add additional power supplies, and the cost is low.

[0080] An embodiment of the present application further provides an electronic device, which includes a switch and a control circuit 100 based on a single switch in any embodiment of the present application, wherein the switch is connected between an AC power source and a control circuit.

[0081] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0082] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Under the idea of ​​the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. It should be understood by ordinary technicians in this field that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A control circuit based on a single switch, characterized in that: The switch is connected between the AC power supply and the control circuit, and the control circuit includes a rectifying branch, a clamping branch, a unidirectional conductive branch, an energy storage branch and a controller; The switch is connected between the AC power source and the rectifying branch, the rectifying branch, the clamping branch, the unidirectional conductive branch and the controller are connected to a first node, and the unidirectional conductive branch, the energy storage branch and the controller are connected to a second node; The rectifying branch is configured to rectify the AC power supply into a DC power supply and input the DC power supply to the first node; The clamping branch is configured to clamp the voltage of the first node; The controller is configured to determine whether the switch is open based on the voltage of the first node; The unidirectional conductive branch is configured to be turned on in response to the voltage of the first node being greater than the voltage of the second node, so as to power the controller based on the voltage of the second node, and to be turned off when the voltage of the second node is greater than the voltage of the first node; The energy storage branch is configured to store electric energy when the unidirectional conductive branch is turned on, and release electric energy when the unidirectional conductive branch is turned off.

2. The control circuit according to claim 1, characterized in that: The control circuit further includes a protection branch and a voltage reduction branch, and the switch is connected to the rectification branch through the protection branch and the voltage reduction branch in sequence; The protection branch is configured to limit current and filter the AC power supply and implement overvoltage protection; The step-down branch is configured to generate a capacitive reactance to step down the AC power supply and then input the AC power supply into the rectifying branch, and the AC power supply is rectified into the DC power supply by the rectifying branch.

3. The control circuit according to claim 1 or 2, characterized in that: The control circuit further includes a switch branch, wherein the switch branch is connected between the rectifier branch and the first node, the switch branch is connected between the switch and the load, and the switch branch is also connected to the controller; The switch branch is configured to disconnect the switch from the load in response to a first control signal output by the controller, so that the AC power source stops supplying power to the load; The switch branch is further configured to conduct the connection between the switch and the load in response to a second control signal output by the controller, so that the AC power source supplies power to the load.

4. The control circuit according to claim 1, characterized in that: The clamping branch includes a first voltage stabilizing diode; An anode of the first Zener diode is grounded, and a cathode of the first Zener diode is connected to the first node.

5. The control circuit according to claim 1, characterized in that: The unidirectional conductive branch includes a first diode; An anode of the first diode is connected to the first node, and a cathode of the first diode is connected to the second node.

6. The control circuit according to claim 1, characterized in that: The energy storage branch includes a first capacitor; The first capacitor is connected between the second node and ground.

7. The control circuit according to claim 2, characterized in that: The protection branch includes a first resistor, a second resistor, a varistor and a second capacitor; The first resistor and the second resistor are connected in series between the switch and the step-down branch, the varistor is connected between a connection point between the first resistor and the second resistor and ground, and the second capacitor is connected in parallel with the varistor.

8. The control circuit according to claim 2, characterized in that: The voltage-reducing branch includes a third resistor and a third capacitor; The third resistor and the third capacitor are connected in parallel between the protection branch and the rectification branch.

9. The control circuit according to claim 3, characterized in that: The switch branch includes a first switch tube, a second switch tube, a fourth resistor, a fifth resistor, a sixth resistor, a fourth capacitor, a fifth capacitor, a second voltage regulator diode and a relay; The first end of the first switch tube is connected to the controller through the fourth resistor, the first end of the first switch tube is also grounded through the fourth capacitor, the second end of the first switch tube is grounded, the third end of the first switch tube is connected to the first end of the second switch tube through the fifth resistor, the second end of the second switch tube is connected to the rectifier branch, the third end of the second switch tube is connected to the first node through the sixth resistor, the fifth capacitor is connected between the second end of the second switch tube and the first node, the anode of the second Zener diode is connected to the first node, the cathode of the second Zener diode is connected to the second end of the second switch tube, the coil of the relay is connected between the second end of the second switch tube and the first node, one of a pair of normally open contacts of the relay is connected to the switch, and the other contact is connected to the load.

10. An electronic device, characterized in that: It comprises a switch and a control circuit based on a single switch as described in any one of claims 1 to 9, wherein the switch is connected between an AC power source and the control circuit.

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