AC overvoltage protection box and film and television lamp system

Abstract

The utility model provides an alternating-current overvoltage protection box and a film and television lamp system, and belongs to the technical field of electronic circuits. The AC overvoltage protection box comprises a housing and a circuit board. The circuit board is arranged in the shell. The shell is provided with an input interface and an output interface, the input interface is used for being connected with an alternating current power supply, and the output interface is used for being connected with alternating current electric equipment. An alternating current overvoltage protection circuit is configured on the circuit board, the alternating current overvoltage protection circuit comprises an alternating current-to-direct current module, a voltage sampling module and a switch control module which are connected in sequence, and when the voltage output by the output end of the voltage sampling module is larger than a first preset threshold value, the switch control module is in an off state; therefore, the connection between the alternating current power supply and the alternating current electric equipment is cut off. The alternating current overvoltage protection box can be connected between alternating current power supply equipment and alternating current electric equipment, and can control a circuit to be disconnected when the voltage of an accessed alternating current power supply is too high, so as to carry out overvoltage protection on the alternating current electric equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuits, and in particular to an alternating current overvoltage protection box and a film and television lamp system. BACKGROUND

[0002] In film and television shooting, high-power film and television lamps are needed to create the light effect required by the scene. The lamp body of the film and television lamp is connected to the mains through an electric box (control box), which converts alternating current into direct current to supply the lamp body. The lamp body contains LED lamp panels, drive boards and heat dissipation components. The electric box also usually has some control circuits, interface circuits (DMX interface, Ethernet interface, type-c port, 3.5mm synchronous jack, etc.), wireless transmission modules and other modules, and can support the connection and control of one or more lamp bodies through the electric box.

[0003] However, many times during film and television shooting, it is outdoor shooting and ordinary mains cannot be used, and alternating current power supply equipment (such as a power generation vehicle) needs to be used. However, the alternating current voltage output by the power generation vehicle is generally high, such as higher than 400 volts or even thousands of volts, and the high voltage can damage the film and television lamp. CONTENT OF THE INVENTION

[0004] The main purpose of the embodiments of the present application is to provide an alternating current overvoltage protection box and a film and television lamp system, which can be connected between alternating current power supply equipment and alternating current electrical equipment, and can control the circuit to be disconnected when the input alternating current voltage is too high, thereby protecting the alternating current electrical equipment from overvoltage.

[0005] To achieve the above purpose, the first aspect of the embodiments of the present application provides an alternating current overvoltage protection box, comprising a shell and a circuit board, wherein the circuit board is arranged in the shell;

[0006] An input interface and an output interface are arranged on the shell, the input interface is used to connect an alternating current power supply, and the output interface is used to connect alternating current electrical equipment;

[0007] An alternating current overvoltage protection circuit is arranged on the circuit board, the alternating current overvoltage protection circuit comprises an alternating current to direct current module, a voltage sampling module and a switch control module, the input end of the alternating current to direct current module is connected to the input interface, the first output end of the alternating current to direct current module is connected to the input end of the voltage sampling module, the output end of the voltage sampling module is connected to the first end of the switch control module, and the second end of the switch control module is connected to the output interface;

[0008] When the voltage output by the output end of the voltage sampling module is greater than a first preset threshold, the switch control module is in a disconnected state to disconnect the connection between the alternating current power supply and the alternating current electrical equipment.

[0009] In an embodiment of the present application, the AC overvoltage protection circuit further comprises an AC relay module, a second output end of the AC-DC module is connected to a first end of the AC relay module, a second end of the switch control module is connected to a second end of the AC relay module, a third end of the AC relay module is connected to the output interface, and a fourth end of the AC relay module is connected to the input interface to access the AC power supply;

[0010] When the voltage output by the output end of the voltage sampling module is greater than the first preset threshold value, the switch control module is in an open state, so that the third end and the fourth end of the AC relay module are disconnected.

[0011] In an embodiment of the present application, the AC-DC module comprises a rectification and voltage reduction unit and a rectification unit, and the rectification and voltage reduction unit is connected in parallel with the rectification unit.

[0012] A first end of the rectification unit is used for connecting the input interface, and a second end of the rectification unit is connected to the input end of the voltage sampling module as a first output end of the AC-DC module.

[0013] A first end of the rectification and voltage reduction unit is used for connecting the input interface, and a second end of the rectification and voltage reduction unit is connected to the first end of the AC relay module as a second output end of the AC-DC module.

[0014] In an embodiment of the present application, the AC overvoltage protection circuit further comprises a hysteresis circuit module.

[0015] The voltage sampling module comprises a first resistance unit and a second resistance unit, the first resistance unit and the second resistance unit are connected in series between the first output end and the ground end of the AC-DC module, and an output end of the voltage sampling module is located between the first resistance unit and the second resistance unit.

[0016] A first end of the hysteresis circuit module is connected to the second output end of the AC-DC module, a second end of the hysteresis circuit module is connected to the output end of the voltage sampling module, and a third end of the hysteresis circuit module is connected to the third end of the switch control module. During the period when the AC power supply is adjusted from a value higher than the first preset threshold value to a second preset threshold value, the voltage superimposed to the second resistance unit by the hysteresis circuit module makes the output voltage of the voltage sampling module remain greater than the switch threshold voltage of the switch control module, so that the switch control module maintains the open state, thereby maintaining the disconnected state between the AC power supply and the AC electrical equipment.

[0017] In an embodiment of the present application, the alternating current overvoltage protection circuit further comprises a voltage stabilizing and filtering module, an input end of the voltage stabilizing and filtering module is connected to an output end of the voltage sampling module, and an output end of the voltage stabilizing and filtering module is connected to a first end of the switch control module.

[0018] In an embodiment of the present application, the alternating current overvoltage protection circuit further comprises an alarm module, a first end of the alarm module is connected to a second output end of the alternating current to direct current module, a second end of the alarm module is connected to an output end of the voltage stabilizing and filtering module, and a third end of the alarm module is connected to a third end of the switch control module.

[0019] In an embodiment of the present application, the alternating current overvoltage protection circuit further comprises a first filtering module and a second filtering module.

[0020] A first end of the first filtering module is connected to a first output end of the alternating current to direct current module, and a second end of the first filtering module is connected to an input end of the voltage sampling module.

[0021] A first end of the second filtering module is connected to a second output end of the alternating current to direct current module, and a second end of the second filtering module is connected to a third output end of the alternating current to direct current module.

[0022] In an embodiment of the present application, the alternating current overvoltage protection circuit further comprises a surge protection module, a first end of the surge protection module is configured to be connected to the input interface, and a second end of the surge protection module is connected to an input end of the alternating current to direct current module.

[0023] In an embodiment of the present application, the circuit board comprises a first circuit board and a second circuit board, the alternating current to direct current module is arranged on the first circuit board, and the voltage sampling module and the switch control module are arranged on the second circuit board.

[0024] In an embodiment of the present application, the first circuit board is vertically arranged on the second circuit board along a width direction.

[0025] In an embodiment of the present application, the shell comprises a bottom shell and a cover plate, an accommodating cavity is formed in the bottom shell, the circuit board is arranged in the accommodating cavity, and the cover plate is detachably connected to the bottom shell.

[0026] In an embodiment of the present application, the circuit board further comprises a communication module, and the communication module is configured to be communicatively connected to an external device.

[0027] To achieve the above object, a second aspect of an embodiment of the present application provides a film and television lamp system, comprising:

[0028] a power box;

[0029] a lamp body;

[0030] The AC overvoltage protection box provided in any embodiment of the present application;

[0031] The input interface of the AC overvoltage protection box is configured to connect to an AC power supply, and the output interface of the AC overvoltage protection box is connected to the electric box, and the electric box is electrically connected to the lamp body.

[0032] In the technical scheme provided in the embodiments of the present application, the AC overvoltage protection box comprises a shell and a circuit board. The circuit board is arranged in the shell. The shell is provided with an input interface and an output interface. The input interface is configured to connect to an AC power supply, and the output interface is configured to connect to an AC electrical device. The circuit board is provided with an AC overvoltage protection circuit. The AC overvoltage protection circuit comprises an AC-to-DC module, a voltage sampling module and a switch control module. The input end of the AC-to-DC module is connected to the input interface. The first output end of the AC-to-DC module is connected to the input end of the voltage sampling module. The output end of the voltage sampling module is connected to the first end of the switch control module. The second end of the switch control module is connected to the output interface. When the voltage output by the output end of the voltage sampling module is greater than a first preset threshold, the switch control module is in an open state to disconnect the connection between the AC power supply and the AC electrical device. The AC overvoltage protection box provided in the present application can be connected between an AC power supply device and an AC electrical device, and can control the circuit to be disconnected when the voltage of the connected AC power supply is too high, thereby protecting the AC electrical device from overvoltage. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a cross-sectional view of the AC overvoltage protection box provided in an embodiment of the present application.

[0034] Figure 2 is a perspective view of the AC overvoltage protection box provided in an embodiment of the present application.

[0035] Figure 3 is an exploded view of the AC overvoltage protection box provided in an embodiment of the present application.

[0036] Figure 4 is a first circuit block diagram of the AC overvoltage protection circuit provided in an embodiment of the present application.

[0037] Figure 5 is a second circuit block diagram of the AC overvoltage protection circuit provided in an embodiment of the present application.

[0038] Figure 6 is a third circuit block diagram of the AC overvoltage protection circuit provided in an embodiment of the present application.

[0039] Figure 7 is a fourth circuit block diagram of the AC overvoltage protection circuit provided in an embodiment of the present application.

[0040] Figure 8 Figure 8 is a fifth circuit block diagram of an AC overvoltage protection circuit according to an embodiment of the present application.

[0041] Figure 9 Figure 9 is a sixth circuit block diagram of an AC overvoltage protection circuit according to an embodiment of the present application.

[0042] Figure 10 Figure 10 is a seventh circuit block diagram of an AC overvoltage protection circuit according to an embodiment of the present application.

[0043] Figure 11 Figure 11 is an eighth circuit block diagram of an AC overvoltage protection circuit according to an embodiment of the present application.

[0044] Figure 12 Figure 12 is a corresponding circuit example diagram according to an embodiment of the present application. Figure 11 Figure 13 is a corresponding circuit example diagram according to an embodiment of the present application.

[0045] Figure 13 Figure 14 is a schematic diagram of a circuit board according to an embodiment of the present application.

[0046] Figure 14 Figure 15 is a schematic diagram of a movie and television light system according to an embodiment of the present application.

[0047] Legend of reference signs:

[0048] 1, AC overvoltage protection box; 2, electrical box; 3, lamp body;

[0049] 100, shell; 200, circuit board; 110, input interface; 120, output interface; 130, bottom shell; 140, cover plate; 400, plug protection cover;

[0050] 300, AC overvoltage protection circuit; 310, AC-to-DC module; 320, voltage sampling module; 330, switch control module; 340, AC relay module; 350, voltage stabilizing and filtering module; 360, alarm module; 370, first filtering module; 380, second filtering module; 390, return difference circuit module; 3100, surge protection module; 311, rectification and voltage reduction unit; 312, rectification unit; 321, first resistance unit; 322, second resistance unit. DETAILED DESCRIPTION

[0051] In order to make the objects, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0052] It should be noted that although the functional modules are divided in the device schematic diagram, the logical order is shown in the flowchart, but in some cases, the steps described or described can be performed in a manner different from the module division in the device or the order in the flowchart. The terms "first", "second", and the like in the description and claims and the above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to limit the present application.

[0054] The camera light is also called video light, film and television light, which is a man-made light source for camera. When the ambient light is too low, the camera must use the device, which is a necessary auxiliary light for photographers and news workers to shoot photos or videos in dark environment. Some film and television lights on the market do not have the function of protecting the input voltage from being too high, so that when the input voltage is too high, the circuit is easily damaged, thereby affecting the service life of the lamp body.

[0055] Therefore, the embodiment of the present application provides an alternating current overvoltage protection box, which can be connected between an alternating current power supply device and an alternating current electrical device (such as a film and television light), and can control the circuit to be disconnected when the input alternating current power supply voltage is too high, thereby protecting the film and television light from overvoltage.

[0056] Reference Figures 1-3 , Figure 1 is a cross-sectional view of the alternating current overvoltage protection box provided by an embodiment of the present application, Figure 2 is a perspective view of the alternating current overvoltage protection box provided by an embodiment of the present application, Figure 3 is an exploded view of the alternating current overvoltage protection box provided by an embodiment of the present application. The alternating current overvoltage protection box 1 comprises a shell 100 and a circuit board 200, and the circuit board 200 is arranged in the shell 100. The shell 100 is provided with an input interface 110 and an output interface 120. The input interface 110 can be used to connect the alternating current power supply, and the output interface 120 can be used to connect the lamp body (such as a film and television light). The circuit board 200 is provided with an alternating current overvoltage protection circuit 300. The alternating current overvoltage protection circuit 300 can control the circuit to be disconnected when the input alternating current power supply voltage is too high, thereby protecting the alternating current electrical device (such as a film and television light) from overvoltage.

[0057] Reference Figure 3The shell 100 includes a bottom shell 130 and a cover plate 140. The bottom shell 130 is internally formed with a cavity, and the circuit board 200 is arranged in the cavity. The cover plate 140 is detachably connected to the bottom shell 130. The cover plate 140 is detachably connected to the bottom shell 130 by buckling, screwing or sliding rail, etc. The shell 100 can be quickly opened, and the fuse elements (such as a pressure sensitive resistor and a fuse) on the circuit board 200 can be checked or replaced. The cover plate 140 and the bottom shell 130 can also be locked by multiple points (such as four corner screws + middle buckling), so that external mechanical stress is dispersed, and the internal circuit still maintains functional integrity when falling or colliding. The combination of the cover plate 140 and the bottom shell 130 can be provided with a sealing rubber ring or a pouring structure to prevent external moisture and dust from entering to cause a short circuit of the circuit, and to inhibit internal arc leakage when an overvoltage fault occurs, thereby reducing the risk of fire. The shell is designed in a split structure of the cover plate 140 and the bottom shell 130, so that the maintenance cost is reduced. When the cover plate 140 or the circuit board 200 is damaged, only the damaged cover plate 140 or the circuit board 200 needs to be replaced, and the entire shell does not need to be scrapped.

[0058] With reference to the foregoing Figure 3 , the input interface 110 and the output interface 120 can be fixed to the side wall of the shell 100 by buckling or screwing, and are matched with the design of the detachable cover plate 140, so that the damaged interface can be replaced, and the maintenance cost is reduced. The input interface 110 can be connected to an alternating current power supply device (such as a power generation vehicle), and the output interface 120 can be a cable type interface and can be directly or indirectly connected to an alternating current power consumption device, such as directly connected to a film and television lamp body or connected to an electric box (the electric box is connected to the film and television lamp body) to indirectly connect to the film and television lamp body.

[0059] With reference to the foregoing Figures 1-3 , the alternating current overvoltage protection box 1 further includes a plug protection cover 400. The plug protection cover 400 is embedded with the shell of the input interface 110 by elastic buckling. Thus, dust and liquid can be blocked from entering the input interface 110, and the alternating current overvoltage protection box 1 can be applied to an outdoor open-air scene.

[0060] With reference to the foregoing Figure 4 , Figure 4 is a first circuit diagram of an alternating current overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 4 , the alternating current overvoltage protection circuit 300 includes an alternating current to direct current module 310, a voltage sampling module 320 and a switch control module 330. The input end of the alternating current to direct current module 310 is connected to an input interface J1 (that is, the input interface 110). The first output end of the alternating current to direct current module 310 is connected to the input end of the voltage sampling module 320. The output end of the voltage sampling module 320 is connected to the first end of the switch control module 330. The second end of the switch control module 330 is connected to an output interface J2 (that is, the output interface 120).

[0061] The AC-to-DC module 310 converts the input AC power to DC power to provide operating power for other circuit modules (such as the voltage sampling module 320 and the switch control module 330). The voltage sampling module 320 samples and detects the voltage of the input AC power supply and sends a trigger signal to the switch control module 330 when overvoltage occurs. The switch control module 330 receives the signal output from the voltage sampling module 320 to control the connection between the AC voltage and the AC electrical equipment, performing overvoltage protection. In this embodiment, when the voltage output from the voltage sampling module 320 exceeds a first preset threshold, the switch control module 330 is in an off state to disconnect the AC power supply from the AC electrical equipment. That is, when the voltage output from the voltage sampling module 320 exceeds the first preset threshold, this voltage can control the switch control module 330 to disconnect, thereby disconnecting the AC power supply from the AC electrical equipment. Therefore, the control circuit can be disconnected when the input AC power voltage is too high to provide overvoltage protection for the AC electrical equipment.

[0062] Reference Figure 5 , Figure 5 This is a second circuit block diagram of an AC overvoltage protection circuit provided in one embodiment of this application. Figure 5 As shown, the AC overvoltage protection circuit 300 includes an AC-to-DC module 310, a voltage sampling module 320, a switch control module 330, and an AC relay module 340. The input terminal of the AC-to-DC module 310 is connected to input interface J1 (i.e., input interface 110). The first output terminal of the AC-to-DC module 310 is connected to the input terminal of the voltage sampling module 320. The second output terminal of the AC-to-DC module 310 is connected to the first terminal of the AC relay module 340. The output terminal of the voltage sampling module 320 is connected to the first terminal of the switch control module 330. The second terminal of the switch control module 330 is connected to the second terminal of the AC relay module 340. The third terminal of the AC relay module 340 is connected to output interface J2 (i.e., output interface 120). The fourth terminal of the AC relay module 340 is connected to input interface J1 to connect to AC power. Alternatively, the fourth terminal of the AC relay module 340 can be connected to the input interface to connect to the neutral wire N of the AC power supply.

[0063] In this embodiment, when the voltage output by the voltage sampling module 320 exceeds a first preset threshold, the switch control module 330 is in an open state, thereby disconnecting the third and fourth terminals of the AC relay module 340, thus disconnecting the AC power supply from the AC electrical equipment. Therefore, the control circuit can be disconnected when the connected AC power supply voltage is too high, providing overvoltage protection for the AC electrical equipment.

[0064] Reference Figure 6 , Figure 6This is a third circuit block diagram of an AC overvoltage protection circuit provided in an embodiment of this application. Figure 6 As shown, the AC overvoltage protection circuit 300 includes an AC-to-DC module 310, a voltage sampling module 320, a switch control module 330, and an AC relay module 340. The AC-to-DC module 310 includes a rectifier-to-step-down unit 311 and a rectifier unit 312, which are connected in parallel. The first terminal of the rectifier unit 312 is connected to the input interface J1 (i.e., input interface 110) to access AC power, and the second terminal of the rectifier unit 312 serves as the first output terminal of the AC-to-DC module 310, connected to the input terminal of the voltage sampling module 320. The first terminal of the rectifier-to-step-down unit 311 is connected to the input interface J1 (i.e., input interface 110) to access AC power, and the second terminal of the rectifier-to-step-down unit 311 serves as the second output terminal of the AC-to-DC module 310, connected to the first terminal of the AC relay module 340. The output terminal of the voltage sampling module 320 is connected to the first terminal of the switch control module 330, the second terminal of the switch control module 330 is connected to the second terminal of the AC relay module 340, the third terminal of the AC relay module 340 is connected to the output interface J2 (i.e., the output interface 120), and the fourth terminal of the AC relay module 340 is connected to the input interface J1 to access the AC power supply.

[0065] In this embodiment, when the voltage output by the voltage sampling module 320 exceeds a first preset threshold, the switch control module 330 is in an open state, thereby disconnecting the third and fourth terminals of the AC relay module 340, thus disconnecting the AC power supply from the AC electrical equipment. Therefore, the control circuit can be disconnected when the connected AC power supply voltage is too high, providing overvoltage protection for the AC electrical equipment.

[0066] In this embodiment, considering that different circuit modules operate at different voltages, the AC-to-DC module 310 can be divided into a rectifier-step-down unit 311 and a rectifier unit 312. The rectifier-step-down unit 311 converts the incoming AC power to DC power and then steps it down, for example, to 24V, to power circuit modules such as the AC relay module 340. The rectifier unit 312 converts the incoming AC power to DC power to power the voltage sampling circuit module 320 and the switch control module 330, etc. This satisfies the power supply requirements of different circuit modules.

[0067] The rectifier unit 312 can employ a half-wave rectifier circuit, a full-wave rectifier circuit (such as a bridge full-wave rectifier), etc. The rectifier-step-down unit 311 can include a rectifier circuit and a step-down circuit. The rectifier circuit can employ a half-wave rectifier circuit, a full-wave rectifier circuit (such as a bridge full-wave rectifier), etc., and the step-down circuit can employ a resistor-capacitor step-down circuit, a DC-DC step-down circuit, etc.

[0068] With reference to Figure 7 , Figure 7 is a fourth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 7 , the AC overvoltage protection circuit 300 includes an AC-to-DC module 310, a voltage sampling module 320, a switch control module 330, an AC relay module 340, and a voltage stabilizing and filtering module 350. The AC-to-DC module 310 includes a rectification and voltage reduction unit 311 and a rectification unit 312, which are connected in parallel. The first end of the rectification unit 312 is used to connect to the input interface J1 (i.e., the input interface 110) to access an AC power source, and the second end of the rectification unit 312 is connected to the input end of the voltage sampling module 320 as the first output end of the AC-to-DC module 310. The first end of the rectification and voltage reduction unit 311 is used to connect to the input interface J1 (i.e., the input interface 110) to access an AC power source, and the second end of the rectification and voltage reduction unit 311 is connected to the first end of the AC relay module 340 as the second output end of the AC-to-DC module 310. The input end of the voltage stabilizing and filtering module 350 is connected to the output end of the voltage sampling module 320, the output end of the voltage stabilizing and filtering module 350 is connected to the first end of the switch control module 330, the second end of the switch control module 330 is connected to the second end of the AC relay module 340, the third end of the AC relay module 340 is connected to the output interface J2 (i.e., the output interface 120), and the fourth end of the AC relay module 340 is connected to the input interface J1 to access an AC power source.

[0069] In the embodiment of the present application, when the voltage output by the output end of the voltage sampling module 320 is greater than a first preset threshold, the switch control module 330 is in an open state, so that the third end and the fourth end of the AC relay module 340 are disconnected, thereby disconnecting the connection between the AC power source and the AC electrical equipment. Thus, the circuit can be controlled to be disconnected when the voltage of the accessed AC power source is too high, thereby providing overvoltage protection for the AC electrical equipment.

[0070] In the embodiment of the present application, the voltage stabilizing and filtering module 350 can include a voltage stabilizing part and a filtering part. The voltage stabilizing part can include a voltage stabilizing diode, and the voltage stabilizing part is configured to control the voltage fluctuation of the output of the voltage sampling module 320 within a certain range, so as to ensure that the output voltage is stable. The voltage stabilizing part can avoid frequent switching of the circuit on or off due to voltage fluctuation. The filtering part can include a resistor and a capacitor. The filtering part is configured to further remove the alternating component and noise component of the output of the voltage sampling module 320, so that the output voltage is more stable. Specifically, the filtering part can use the energy storage and release characteristics of the capacitor to filter the signal output by the output of the voltage sampling module 320. The capacitor can be used to store electric charge, smooth voltage fluctuation, and particularly used to filter out the alternating component and reduce the ripple of the output voltage. The resistor can be used to control the current or form an RC filter together with the capacitor, so as to control the frequency response of the filter.

[0071] Referring to Figure 8 , Figure 8 is a fifth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 8 , the AC overvoltage protection circuit 300 includes an AC-to-DC module 310, a voltage sampling module 320, a switch control module 330, an AC relay module 340, a voltage stabilizing and filtering module 350, and an alarm module 360. The AC-to-DC module 310 includes a rectification and voltage reduction unit 311 and a rectification unit 312, and the rectification and voltage reduction unit 311 is connected in parallel with the rectification unit 312. A first end of the rectification unit 312 is configured to be connected to an input interface J1 (i.e., the input interface 110) to access an AC power supply, and a second end of the rectification unit 312 is connected to an input end of the voltage sampling module 320 as a first output end of the AC-to-DC module 310. A first end of the rectification and voltage reduction unit 311 is configured to be connected to the input interface J1 (i.e., the input interface 110) to access the AC power supply, and a second end of the rectification and voltage reduction unit 311 is connected to a first end of the alarm module 360 and a first end of the AC relay module 340 as a second output end of the AC-to-DC module 310. The rectification and voltage reduction unit 311 and the rectification unit 312 are configured to supply power to the alarm module 360 and the AC relay module 340. An output end of the voltage sampling module 320 is connected to an input end of the voltage stabilizing and filtering module 350, an output end of the voltage stabilizing and filtering module 350 is connected to a first end of the switch control module 330, the output end of the voltage stabilizing and filtering module 350 is also connected to a second end of the alarm module 360, and a third end of the alarm module 360 is connected to a third end of the switch control module 330. A second end of the switch control module 330 is connected to a second end of the AC relay module 340, a third end of the AC relay module 340 is connected to an output interface J2 (i.e., the output interface 120), and a fourth end of the AC relay module 340 is connected to the input interface J1 to access the AC power supply.

[0072] In the embodiment, when the voltage outputted by the output terminal of the voltage sampling module 320 is greater than the first preset threshold, the switch control module 330 is in the off state, so that the third terminal and the fourth terminal of the AC relay module 340 are disconnected, thereby disconnecting the connection between the AC power supply and the AC electrical equipment. Thus, the circuit can be disconnected when the input AC power supply voltage is too high, thereby protecting the AC electrical equipment from overvoltage. Meanwhile, when the voltage outputted by the output terminal of the voltage sampling module 320 is greater than the first preset threshold, the switch control module 30 can control the alarm module 360 to be conductive, thereby issuing an alarm. When the voltage outputted by the output terminal of the voltage sampling module 320 is less than or equal to the first preset threshold, the switch control module 30 can control the alarm module 360 to be non-conductive, thereby not issuing an alarm. That is, through the setting of the alarm module 360, an alarm can be issued in the overvoltage state, thereby prompting that the input AC voltage is too high.

[0073] The alarm module 360 can include an audible alarm circuit or a light alarm circuit or an audible and light alarm circuit, that is, the alarm module 360 can adopt an audible alarm circuit, which can issue an audible alarm to remind that the voltage is too high when the voltage outputted by the output terminal of the voltage sampling module 320 is too high. The alarm module 360 can also adopt a light alarm circuit, which can issue a light alarm (such as a bright light or a flashing light) to remind the user that the voltage is too high when the voltage outputted by the output terminal of the voltage sampling module 320 is too high. The alarm module 360 can also adopt an audible and light alarm circuit, which can issue an audible and light alarm to remind the user that the voltage is too high when the voltage outputted by the output terminal of the voltage sampling module 320 is too high.

[0074] Referring to Figure 9 , Figure 9 is a sixth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. The AC overvoltage protection circuit includes a voltage sampling module 320, a switch control module 330, an AC relay module 340, and an alarm module 360. Figure 9As shown, the AC overvoltage protection circuit 300 includes an AC-to-DC module 310, a voltage sampling module 320, a switch control module 330, an AC relay module 340, a voltage stabilizing and filtering module 350, an alarm module 360, a first filtering module 370, and a second filtering module 380. The AC-to-DC module 310 includes a rectification and voltage reduction unit 311 and a rectification unit 312, which are connected in parallel. The first end of the rectification unit 312 is configured to be connected to the input interface J1 (i.e., the input interface 110) to access an AC power supply, and the second end of the rectification unit 312 is connected to the input end of the voltage sampling module 320 as the first output end of the AC-to-DC module 310. The first end of the rectification and voltage reduction unit 311 is configured to be connected to the input interface J1 (i.e., the input interface 110) to access the AC power supply, and the second end of the rectification and voltage reduction unit 311 is connected to the first end of the alarm module 360 and the first end of the AC relay module 340 as the second output end of the AC-to-DC module 310. The rectification and voltage reduction unit 311 and the rectification unit 312 provide power supply for the alarm module 360 and the AC relay module 340. The input end of the voltage stabilizing and filtering module 350 is connected to the output end of the voltage sampling module 320, the output end of the voltage stabilizing and filtering module 350 is connected to the first end of the switch control module 330, the output end of the voltage stabilizing and filtering module 350 is also connected to the second end of the alarm module 360, and the third end of the alarm module 360 is connected to the third end of the switch control module 330. The second end of the switch control module 330 is connected to the second end of the AC relay module 340, the third end of the AC relay module 340 is connected to the output interface J2 (i.e., the output interface 120), and the fourth end of the AC relay module 340 is connected to the input interface J1 to access the AC power supply. The first end of the first filtering module 370 is connected to the second end of the rectification unit 312, and the second end of the first filtering module 370 is connected to the input end of the voltage sampling module 320. The first end of the second filtering module 380 is connected to the second end of the rectification and voltage reduction unit 311, and the second end of the second filtering module 380 is connected to the third end of the rectification and voltage reduction unit 311.

[0075] In the embodiment of the present application, when the voltage output by the output end of the voltage sampling module 320 is greater than the first preset threshold, the switch control module 330 is in an open state, so that the third end and the fourth end of the AC relay module 340 are disconnected, thereby disconnecting the connection between the AC power supply and the AC electrical equipment. Thus, the circuit can be disconnected when the voltage of the accessed AC power supply is too high, thereby providing overvoltage protection for the AC electrical equipment.

[0076] In the embodiment of the present application, the first filtering module 370 and the second filtering module 380 each include a filtering capacitor. The filtering capacitor smoothes the AC signal through a charging and discharging process, removes unnecessary AC components, retains DC components, and thus provides stable DC output.

[0077] Referring to Figure 10 ,Figure 10 is a seventh circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 10 The AC overvoltage protection circuit 300 includes an AC-to-DC module 310, a voltage sampling module 320, a switch control module 330, an AC relay module 340, a voltage stabilizing and filtering module 350, an alarm module 360, a first filtering module 370, a second filtering module 380, and a hysteresis circuit module 390. The AC-to-DC module 310 includes a rectification and voltage reduction unit 311 and a rectification unit 312, which are connected in parallel. The first end of the rectification unit 312 is used to connect to the input interface J1 (i.e., the input interface 110) to access an AC power source, and the second end of the rectification unit 312 is connected to the input end of the voltage sampling module 320 as the first output end of the AC-to-DC module 310. The first end of the rectification and voltage reduction unit 311 is used to connect to the input interface J1 (i.e., the input interface 110) to access an AC power source, and the second end of the rectification and voltage reduction unit 311 is connected to the first end of the alarm module 360 and the first end of the AC relay module 340 as the second output end of the AC-to-DC module 310. This provides power supply for the alarm module 360 and the AC relay module 340. The input end of the voltage stabilizing and filtering module 350 is connected to the output end of the voltage sampling module 320, the output end of the voltage stabilizing and filtering module 350 is connected to the first end of the switch control module 330, the output end of the voltage stabilizing and filtering module 350 is also connected to the second end of the alarm module 360, and the third end of the alarm module 360 is connected to the third end of the switch control module 330. The second end of the switch control module 330 is connected to the second end of the AC relay module 340, the third end of the AC relay module 340 is connected to the output interface J2 (i.e., the output interface 120), and the fourth end of the AC relay module 340 is connected to the input interface J1 to access an AC power source. The first end of the first filtering module 370 is connected to the second end of the rectification unit 312, and the second end of the first filtering module 370 is connected to the input end of the voltage sampling module 320. The first end of the second filtering module 380 is connected to the second end of the rectification and voltage reduction unit 311, and the second end of the second filtering module 380 is connected to the third end of the rectification and voltage reduction unit 311.

[0078] The voltage sampling module 320 includes a first resistance unit 321 and a second resistance unit 322. The first resistance unit 321 and the second resistance unit 322 are connected in series between the second end of the rectification unit 312 and the ground end GND, and the output end of the voltage sampling module 320 is located between the first resistance unit 321 and the second resistance unit 322. The first end of the hysteresis circuit module 390 is connected to the second end of the rectification and voltage reduction unit 311, the second end of the hysteresis circuit module 390 is connected to the output end of the voltage sampling module 320, and the third end of the hysteresis circuit module 390 is connected to the third end of the switch control module 330.

[0079] When the AC power supply is from the first preset threshold to the second preset threshold, the voltage superimposed by the hysteresis circuit module 390 to the second resistance unit 322 makes the output of the voltage sampling module 320 keep the output voltage greater than the switching threshold voltage of the switch control module 330, so that the switch control module 330 maintains the open state, to maintain the disconnected state between the AC power supply and the AC load.

[0080] In the embodiment of the application, when the voltage output by the output end of the voltage sampling module 320 is greater than the first preset threshold, the switch control module 330 is in the open state, so that the third end and the fourth end of the AC relay module 340 are disconnected, thereby the connection between the AC power supply and the AC load can be disconnected. Thus, the circuit can be disconnected when the input AC power supply voltage is too high, to protect the AC load from overvoltage.

[0081] In the embodiment of the application, the hysteresis range can be controlled by adjusting the resistance voltage division ratio (such as R1 / R2), to match the grid fluctuation characteristics. When the input AC voltage is close to the overvoltage threshold (the first preset threshold), the grid noise or transient fluctuation may cause the detection signal to jitter around the critical value. The hysteresis circuit module 390 can avoid the protection circuit from repeatedly switching states due to small disturbances, by setting the difference between the trigger voltage (V th1 ) and the release voltage (V th2 ) (such as 280V trigger, 260V release). Once the overvoltage is triggered, the circuit needs to be reset only after the voltage drops to a lower threshold (V th2 ), which can force a stable protection period and prevent the load from being frequently powered off in voltage fluctuations. The hysteresis window (such as 20V-50V) can provide a buffer interval for voltage changes, to ensure that the protection action is triggered only in actual overvoltage events, not in transient abnormalities. That is, the embodiment of the application can ensure that the AC overvoltage protection is triggered only when the overvoltage is continuous, to avoid false actions that damage system stability, solve the problem of frequent triggering near the threshold, and improve the reliability and stability of the protection action.

[0082] Referring to Figure 11 , Figure 11 is an eighth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the application. The Figure 11As shown, the AC overvoltage protection circuit 300 includes an AC-DC module 310, a voltage sampling module 320, a switch control module 330, an AC relay module 340, a voltage stabilizing and filtering module 350, an alarm module 360, a first filtering module 370, a second filtering module 380, a back-off circuit module 390, and a surge protection module 3100. The first end of the surge protection module 3100 is connected to the input interface J1 (i.e., the input interface 110), and the second end of the surge protection module 3100 is connected to the input end of the AC-DC module 310. The AC-DC module 310 includes a rectification and voltage reduction unit 311 and a rectification unit 312, which are connected in parallel. The first end of the rectification unit 312 is connected to the input interface J1 (i.e., the input interface 110) to access the AC power supply, and the second end of the rectification unit 312 is connected to the input end of the voltage sampling module 320 as the first output end of the AC-DC module 310. The first end of the rectification and voltage reduction unit 311 is connected to the input interface J1 (i.e., the input interface 110) to access the AC power supply, and the second end of the rectification and voltage reduction unit 311 is connected to the first end of the alarm module 360 and the first end of the AC relay module 340 as the second output end of the AC-DC module 310. This provides power for the alarm module 360 and the AC relay module 340. The input end of the voltage stabilizing and filtering module 350 is connected to the output end of the voltage sampling module 320, the output end of the voltage stabilizing and filtering module 350 is connected to the first end of the switch control module 330, the output end of the voltage stabilizing and filtering module 350 is also connected to the second end of the alarm module 360, and the third end of the alarm module 360 is connected to the third end of the switch control module 330. The second end of the switch control module 330 is connected to the second end of the AC relay module 340, the third end of the AC relay module 340 is connected to the output interface J2 (i.e., the output interface 120), and the fourth end of the AC relay module 340 is connected to the input interface J1 to access the AC power supply. The first end of the first filtering module 370 is connected to the second end of the rectification unit 312, and the second end of the first filtering module 370 is connected to the input end of the voltage sampling module 320. The first end of the second filtering module 380 is connected to the second end of the rectification and voltage reduction unit 311, and the second end of the second filtering module 380 is connected to the third end of the rectification and voltage reduction unit 311.

[0083] The voltage sampling module 320 includes a first resistance unit 321 and a second resistance unit 322. The first resistance unit 321 and the second resistance unit 322 are connected in series between the second end of the rectification unit 312 and the ground end GND, and the output end of the voltage sampling module 320 is located between the first resistance unit 321 and the second resistance unit 322. The first end of the back-off circuit module 390 is connected to the second end of the rectification and voltage reduction unit 311, the second end of the back-off circuit module 390 is connected to the output end of the voltage sampling module 320, and the third end of the back-off circuit module 390 is connected to the third end of the switch control module 330.

[0084] When the AC power supply is stepped down from above the first preset threshold to the second preset threshold, the voltage superimposed by the hysteresis circuit module 390 to the second resistance unit 322 causes the output end of the voltage sampling module 320 to maintain an output voltage greater than the switching threshold voltage of the switch control module 330, so that the switch control module 330 maintains the open state to maintain the disconnected state between the AC power supply and the AC electrical equipment.

[0085] In the embodiment of the application, when the voltage output by the output end of the voltage sampling module 320 is greater than the first preset threshold, the switch control module 330 is in the open state, so that the third end and the fourth end of the AC relay module 340 are disconnected, thereby disconnecting the connection between the AC power supply and the AC electrical equipment. Thus, the circuit can be disconnected when the voltage of the connected AC power supply is too high, thereby providing overvoltage protection for the AC electrical equipment.

[0086] In the embodiment of the application, the surge protection module 3100 can realize the dual functions of transient overvoltage suppression and overcurrent fuse protection through the combined design of the MOV and the fuse. Through the cooperation of multiple components such as the MOV and the fuse, the transient high voltage such as lightning and switching surge can be quickly clamped and discharged, while the risk of false triggering of the main overvoltage protection circuit is reduced, thereby ensuring the overall reliability of the system.

[0087] Referring to Figure 12 , Figure 12 is an embodiment of the application Figure 11 corresponding circuit example. Referring to Figure 12 , the voltage sampling module 320 includes resistors R1, R2, R3, R4, R5, R6, R7, R8 and R33 connected in series. Among them, the resistors R1, R2, R3, R4, R5, R6, R7 and R8 constitute the first resistance unit 321, and the resistor R33 constitutes the second resistance unit 322. The output end of the voltage sampling module 320 is located between the resistor R8 and the resistor R33.

[0088] The voltage sampling module 320 includes resistors R1, R2, R3, R4, R5, R6, R7, R8 and R33 connected in series. Among them, the resistors R1, R2, R3, R4, R5, R6, R7 and R8 constitute the first resistance unit 321, and the resistor R33 constitutes the second resistance unit 322. The output end of the voltage sampling module 320 is located between the resistor R8 and the resistor R33.

[0089] The switch control module 330 comprises a first diode D4, a first capacitor C7, a second capacitor C12, a first voltage stabilizing diode D12, a first resistor R32, a second resistor R16 and a first triode Q5. The negative electrode of the first diode D4 is connected to the output end of the voltage stabilizing and filtering module 350, i.e. the third end of the three-terminal voltage stabilizing tube D11. The positive electrode of the first voltage stabilizing diode D12 is connected to the first end of the first resistor R32. The second end of the first resistor R32 is connected to the second output end of the AC-DC conversion module 310. The first end of the first capacitor C7 is connected between the positive electrode of the first voltage stabilizing diode D12 and the first end of the first resistor R32. The second end of the first capacitor C7 is grounded. The negative electrode of the first voltage stabilizing diode D12 is connected to the first end of the first resistor R32. The positive electrode of the first voltage stabilizing diode D12 is connected to the first end of the second resistor R16. The second end of the second resistor R16 is grounded. The negative electrode of the first voltage stabilizing diode D12 is also connected to the base of the first triode Q5. The first end of the second capacitor C12 is connected between the negative electrode of the first voltage stabilizing diode D12 and the base of the first triode Q5. The second end of the second capacitor C12 is grounded. The emitter of the first triode Q5 is grounded. The collector of the first triode Q5 is connected to the second end of the AC relay module 340.

[0090] In the embodiment of the present application, when the voltage outputted by the output end of the voltage sampling module 320 is not greater than the first preset threshold value, i.e. does not exceed the reference voltage Vr of the three-terminal voltage stabilizing tube D11, the cathode and the anode of the three-terminal voltage stabilizing tube D11 are not conductive, so that the first diode D4 is not conductive, the first voltage stabilizing diode D12 is reversely broken down, the control end (i.e. the base) of the first triode Q5 is at a high level, the first triode Q5 is conductive, and the connection between the AC power supply and the AC electrical equipment is conductive. When the voltage outputted by the output end of the voltage sampling module 320 is greater than the first preset threshold value, i.e. exceeds the reference voltage Vr of the three-terminal voltage stabilizing tube D11, the three-terminal voltage stabilizing tube D11 is reversely conductive, so that the first diode D4 is forwardly conductive, the control end (i.e. the base) of the first triode Q5 is pulled down and disconnected, and the connection between the AC power supply and the AC electrical equipment is disconnected.

[0091] The AC relay module 340 includes a first AC relay J1, a second AC relay J3, and a second diode D5. The negative electrode of the second diode D5 is connected to the second output end of the AC-DC conversion module 310, and the positive electrode of the second diode D5 is connected to the second end of the switch control module 330, i.e., the collector of the first triode Q5. The first AC relay J1 and the second AC relay J3 are connected in parallel between the power supply end (neutral line N) of the AC power supply and the wiring end (such as the lamp body N) of the AC electrical equipment. Among them, the first AC relay J1 and the second AC relay J3 form a redundant structure in parallel, and if any AC relay is burned out due to contact aging or overcurrent, the other AC relay can still maintain the neutral line passage to ensure that the lamp body circuit can still be normally restored after the overvoltage protection trigger. Under the overvoltage state, the AC relay needs to frequently cut off the high-voltage current, and the parallel design can share the contact on-off pressure and reduce the risk of single contact arc damage.

[0092] In the embodiment of the present application, when the voltage output by the output end of the voltage sampling module 320 is not greater than the first preset threshold value, i.e., does not exceed the reference voltage Vr of the three-terminal voltage regulator D11, the cathode and anode of the three-terminal voltage regulator D11 are not conductive, so that the first diode D4 is not conductive, the first zener diode D12 is reversely broken down, and the control end (i.e., the base) of the first triode Q5 is high level, and the first triode Q5 is conductive. Therefore, the state of the first AC relay J1 and the second AC relay J3 is that the terminal point 3 is connected to the terminal point 1, i.e., the AC electrical equipment is normally connected to the power supply end (neutral line N) of the AC power supply. When the voltage output by the output end of the voltage sampling module 320 is greater than the first preset threshold value, i.e., exceeds the reference voltage Vr of the three-terminal voltage regulator D11, the three-terminal voltage regulator D11 is reversely conductive, so that the first diode D4 is forwardly conductive, and the control end (i.e., the base) of the first triode Q5 is pulled low to be disconnected. Therefore, the state of the first AC relay J1 and the second AC relay J3 is that the terminal point 3 is connected to the terminal point 2, i.e., the power supply end (neutral line N) of the AC power supply is disconnected from the AC electrical equipment, thereby achieving AC overvoltage protection for the AC electrical equipment.

[0093] The alarm module 360 comprises a third diode D3, a third resistor R11, a fourth resistor R30, a fifth resistor R29, a second triode Q3 and a buzzer LS2. The negative electrode of the third diode D3 is connected to the output end of the voltage stabilizing and filtering module 350, i.e. connected to the third end of the three-terminal voltage stabilizing tube D11, and the positive electrode of the third diode D3 is connected to the first end of the third resistor R11. The second end of the third resistor R11 is connected to the first end of the fourth resistor R30, and the second end of the fourth resistor R30 is connected to the second output end of the AC-DC conversion module 310. The base of the second triode Q3 is connected between the second end of the third resistor R11 and the first end of the fourth resistor R30, the collector of the second triode Q3 is grounded, and the emitter of the second triode Q3 is connected to the first end of the buzzer. The second end of the buzzer is connected to the first end of the fifth resistor, and the second end of the fifth resistor is connected to the second output end of the AC-DC conversion module 310.

[0094] In the embodiment of the present application, when the voltage outputted by the output end of the voltage sampling module 320 is not greater than the first preset threshold value, i.e. does not exceed the reference voltage Vr of the three-terminal voltage stabilizing tube D11, the cathode and the anode of the three-terminal voltage stabilizing tube D11 are not conductive, the third diode D3 is not conductive, the control end (i.e. the base) of the second triode Q3 is at a high level, the second triode Q3 is turned off, and the buzzer does not sound. When the voltage outputted by the output end of the voltage sampling module 320 is greater than the first preset threshold value, i.e. exceeds the reference voltage Vr of the three-terminal voltage stabilizing tube D11, the three-terminal voltage stabilizing tube D11 is reversely conductive, so that the third diode D3 is forwardly conductive, the control end (i.e. the base) of the second triode Q3 is pulled low and thus is conductive, and the buzzer sounds to perform overvoltage alarm and warning.

[0095] The return difference circuit module 390 comprises a fourth diode D2, a fifth diode D1, a sixth resistor R9, a seventh resistor R10, an eighth resistor R12, a ninth resistor R13 and a third triode Q2. The negative electrode of the fourth diode D2 is connected to the output end of the voltage stabilizing and filtering module 350, i.e. connected to the third end of the three-terminal voltage stabilizing tube D11, and the positive electrode of the fourth diode D2 is connected to the first end of the seventh resistor R10. The second end of the seventh resistor R10 is connected to the first end of the sixth resistor, and the second end of the sixth resistor is connected to the second output end of the AC-DC conversion module 310. The base of the third triode Q2 is connected between the second end of the seventh resistor R10 and the first end of the sixth resistor R9, the emitter of the third triode Q2 is connected to the second output end of the AC-DC conversion module 310, the collector of the third triode Q2 is connected to the first end of the ninth resistor R13, the second end of the ninth resistor R13 is connected to the first end of the eighth resistor R12, the second end of the eighth resistor R12 is connected to the positive electrode of the fifth diode D1, and the negative electrode of the fifth diode D1 is connected to the output end of the voltage sampling module 320.

[0096] In the embodiment of the present application, when the voltage outputted by the output end of the voltage sampling module 320 is not greater than the first preset threshold, i.e. does not exceed the reference voltage Vr of the three-terminal voltage regulator D11, the cathode and the anode of the three-terminal voltage regulator D11 are not conductive, the fourth diode D2 is not conductive, the control end (i.e. the base) of the third triode Q2 is at a high level, and the third triode Q2 is turned off, so that no current flows through the ninth resistor R13, the eighth resistor R12 and the fifth diode D1 (for current limiting and filtering). When the voltage outputted by the output end of the voltage sampling module 320 is greater than the first preset threshold, i.e. exceeds the reference voltage Vr of the three-terminal voltage regulator D11, the three-terminal voltage regulator D11 is reversely conductive, so that the fourth diode D2 is forwardly conductive, the control end (i.e. the base) of the third triode Q2 is pulled low and thus is conductive, and the ninth resistor R13, the eighth resistor R12 and the fifth diode D1 (for current limiting and filtering) are conductive and have current flowing therethrough.

[0097] Specifically, when the AC power supply makes the voltage drop of the resistor R33 in the voltage sampling module 260 greater than the reference voltage (such as 2.5V), the resistor R33 will be kept at about 2.7V due to the current superimposed small voltage drop (such as 0.2V) after the fourth diode Q2 is turned on. When the AC voltage starts to decrease, the voltage drop of the resistor R33 due to the voltage drop of the input voltage through the voltage dividing network will decrease from the reference voltage, and the voltage drop of the resistor R33 will decrease from 2.7V until the voltage drop of the input voltage through the voltage dividing network decreases from the reference voltage to 2.3V or below, so that the voltage drop of the resistor R33 decreases to 2.5V or below, thereby turning off the cathode and the anode of the three-terminal voltage regulator D11, and maintaining the first triode Q5 of the switch control module 330 in an off state to maintain the state of disconnecting the AC power supply from the AC electrical equipment.

[0098] Referring to Figure 13 , Figure 13 is a schematic diagram of a circuit board provided by an embodiment of the present application. The circuit board 200 includes a first circuit board 210 and a second circuit board 220. The first circuit board 210 is configured with an AC-DC module, and the second circuit board 220 is configured with a voltage sampling module and a switch control module. The second circuit board can also be configured with an AC relay module, a voltage stabilizing and filtering module, an alarm module, a first filtering module, a second filtering module, a back difference circuit module and an anti-surge module.

[0099] In the embodiments of the present application, the AC-to-DC module is a power supply module, and the voltage sampling module, the switch control module, the AC relay module, the voltage stabilizing and filtering module, the alarm module, the first filtering module, the second filtering module, the return difference circuit module and the surge protection module are all power consumption modules. By arranging the AC-to-DC module on the first circuit board 210 and arranging the voltage sampling module, the switch control module, the AC relay module, the voltage stabilizing and filtering module, the alarm module, the first filtering module, the second filtering module, the return difference circuit module and the surge protection module on the second circuit board 220, the power supply module and the power consumption module can be relatively independent, and the detection and maintenance of the AC overvoltage protection circuit are facilitated.

[0100] In some embodiments, with reference to Figure 13 , the first circuit board 210 is vertically arranged on the second circuit board 220 along the width direction, so that the structure of the circuit board 200 is more compact, and the area of the circuit board 200 is reduced.

[0101] In some embodiments, a communication module can also be arranged on the circuit board 220, and the communication module is used for communication connection with an external device. Thus, the communication module can be used to establish a communication connection with an external device (such as a DMX box, a console, a terminal device, etc.), and the external device can be sent alarm information such as icons, pictures, texts, sounds and flashing lights in an overvoltage state, so as to remind the user to timely adjust the output voltage of the AC power supply device according to the alarm information.

[0102] With reference to Figure 14 , Figure 14 is a schematic diagram of a film and television lamp system provided by an embodiment of the present application. The film and television lamp system comprises an AC overvoltage protection box 1 provided by any of the embodiments of the present application, an electric box 2 and a lamp body 3.

[0103] The input interface of the AC overvoltage protection box 1 is used for connecting an AC power supply, i.e. connecting an AC power supply device (such as a power generation vehicle), and the output interface of the AC overvoltage protection box 1 is connected to the electric box 2, and the electric box 2 is electrically connected to the lamp body 3.

[0104] In the embodiments of the present application, by connecting the AC overvoltage protection box 1 between the AC power supply device and the AC power consumption device (the electric box 2), the circuit can be controlled to be disconnected when the voltage of the connected AC power supply is too high, so as to protect the AC power consumption device from overvoltage. The electric box 2 can be electrically connected to multiple lamp bodies 3, and the AC overvoltage protection of the multiple lamp bodies 3 can be simultaneously realized.

[0105] The above describes the preferred embodiments of the embodiments of the present application with reference to the accompanying drawings, but does not limit the scope of the embodiments of the present application. Any modification, equivalent replacement and improvement made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the embodiments of the present application.

Claims

1. An alternating current overvoltage protection box, characterized in that, The shell and a circuit board are arranged in the shell; The shell is provided with an input interface and an output interface, the input interface is used for accessing an alternating current power supply, and the output interface is used for connecting an alternating current electrical equipment; The circuit board is provided with an alternating current overvoltage protection circuit, the alternating current overvoltage protection circuit comprises an alternating current to direct current module, a voltage sampling module and a switch control module, an input end of the alternating current to direct current module is connected to the input interface, a first output end of the alternating current to direct current module is connected to an input end of the voltage sampling module, an output end of the voltage sampling module is connected to a first end of the switch control module, and a second end of the switch control module is connected to the output interface; When the voltage output by the output end of the voltage sampling module is greater than a first preset threshold value, the switch control module is in an open state to disconnect the connection between the alternating current power supply and the alternating current electrical equipment.

2. The AC overvoltage protection box according to claim 1, characterized in that, The alternating current overvoltage protection circuit further comprises an alternating current relay module, a second output end of the alternating current to direct current module is connected to a first end of the alternating current relay module, a second end of the switch control module is connected to a second end of the alternating current relay module, a third end of the alternating current relay module is connected to the output interface, and a fourth end of the alternating current relay module is connected to the input interface to access the alternating current power supply; When the voltage output by the output end of the voltage sampling module is greater than the first preset threshold value, the switch control module is in an open state to disconnect the third end and the fourth end of the alternating current relay module.

3. The AC overvoltage protection box according to claim 2, characterized in that The alternating current to direct current module comprises a rectification and voltage reduction unit and a rectification unit, and the rectification and voltage reduction unit is connected in parallel with the rectification unit; A first end of the rectification unit is used for connecting the input interface, and a second end of the rectification unit is connected to the input end of the voltage sampling module as the first output end of the alternating current to direct current module; A first end of the rectification and voltage reduction unit is used for connecting the input interface, and a second end of the rectification and voltage reduction unit is connected to the first end of the alternating current relay module as the second output end of the alternating current to direct current module.

4. The AC overvoltage protection box according to any one of claims 1 to 3, characterized in that The alternating current overvoltage protection circuit further comprises a hysteresis circuit module; The voltage sampling module comprises a first resistance unit and a second resistance unit, the first resistance unit and the second resistance unit are connected in series between the first output end of the alternating current to direct current module and a ground end, and the output end of the voltage sampling module is located between the first resistance unit and the second resistance unit. The first end of the return difference circuit module is connected to the second output end of the AC-DC module, the second end of the return difference circuit module is connected to the output end of the voltage sampling module, the third end of the return difference circuit module is connected to the third end of the switch control module, and during the return of the AC power supply from above the first preset threshold to the second preset threshold, the voltage superimposed to the second resistance unit by the return difference circuit module makes the output voltage of the voltage sampling module greater than the switch threshold voltage of the switch control module, so that the switch control module maintains the open state, thereby maintaining the disconnected state between the AC power supply and the AC electrical equipment.

5. The AC overvoltage protection box according to claim 1, characterized in that, The AC overvoltage protection circuit further comprises a voltage stabilizing and filtering module, the input end of the voltage stabilizing and filtering module is connected to the output end of the voltage sampling module, and the output end of the voltage stabilizing and filtering module is connected to the first end of the switch control module.

6. The AC overvoltage protection box according to claim 5, characterized in that The AC overvoltage protection circuit further comprises an alarm module, the first end of the alarm module is connected to the second output end of the AC-DC module, the second end of the alarm module is connected to the output end of the voltage stabilizing and filtering module, and the third end of the alarm module is connected to the third end of the switch control module.

7. The AC overvoltage protection box according to claim 1, characterized in that, The AC overvoltage protection circuit further comprises a first filter module and a second filter module. The first end of the first filter module is connected to the first output end of the AC-DC module, and the second end of the first filter module is connected to the input end of the voltage sampling module. The first end of the second filter module is connected to the second output end of the AC-DC module, and the second end of the second filter module is connected to the third output end of the AC-DC module.

8. The AC overvoltage protection box according to claim 1, characterized in that, The AC overvoltage protection circuit further comprises a surge protection module, the first end of the surge protection module is used for connecting the input interface, and the second end of the surge protection module is connected to the input end of the AC-DC module.

9. The AC overvoltage protection box according to claim 1, characterized in that, The circuit board comprises a first circuit board and a second circuit board, the AC-DC module is arranged on the first circuit board, and the voltage sampling module and the switch control module are arranged on the second circuit board.

10. The AC overvoltage protection box according to claim 9, characterized in that, The first circuit board is vertically arranged on the second circuit board in the width direction.

11. The AC overvoltage protection box according to claim 1, characterized in that, The shell comprises a bottom shell and a cover plate, the bottom shell is internally formed with a containing cavity, the circuit board is arranged in the containing cavity, and the cover plate is detachably connected to the bottom shell.

12. The AC overvoltage protection box according to claim 1, characterized in that, The circuit board further comprises a communication module, and the communication module is used for communicating with an external device.

13. A film and television light system characterized by, The AC overvoltage protection box comprises: an electric box; a lamp body; the AC overvoltage protection box according to any one of claims 1-12; wherein the input interface of the AC overvoltage protection box is used for connecting an AC power supply, the output interface of the AC overvoltage protection box is connected to the electric box, and the electric box is electrically connected to the lamp body.

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