Alternating current overvoltage protection circuit and film and television lamp

Abstract

The utility model provides an alternating-current overvoltage protection circuit and a film and television lamp. The alternating-current overvoltage protection circuit comprises a first rectifier module, a voltage division module, a switch control module and an alternating-current relay module. When the voltage output by the second end of the voltage division module is larger than a preset threshold value, the switch control module is in an off state, the third end and the output end of the alternating-current relay module can be disconnected, the film and television lamp and the alternating-current power supply can be disconnected in an overvoltage state, overvoltage protection is carried out on the film and television lamp, and the film and television lamp is prevented from being damaged due to overvoltage. When the voltage output by the second end of the voltage dividing module is smaller than or equal to the preset threshold value, the switch control module is in the conducting state, the third end of the alternating current relay module can be conducted with the output end, in other words, the alternating current power supply provides voltage for the film and television lamp in the non-overvoltage state, and the film and television lamp can work normally.

Description

TECHNICAL FIELD

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

[0002] In movie and television shooting, high-power movie and television lamps are needed to create the light effect required by the scene. However, the high-power movie and television lamps usually need to be powered by an external alternating current power supply. However, due to some differences in the standards and stability of power supply systems in different regions, there is a situation of excessively high voltage of the connected alternating current power supply, and the excessively high voltage will damage the movie and television lamp. Therefore, an alternating current overvoltage protection circuit is needed to protect the movie and television lamp. CONTENT OF THE INVENTION

[0003] The main purpose of the embodiments of the present application is to provide an alternating current overvoltage protection circuit and a movie and television lamp, which can control the circuit to be disconnected when the voltage of the connected alternating current power supply is excessively high, so as to protect the movie and television lamp from overvoltage.

[0004] To achieve the above purpose, a first aspect of the embodiments of the present application provides an alternating current overvoltage protection circuit, which has an input end and an output end, the input end is used to connect an alternating current power supply, the output end is used to connect a movie and television lamp, and the alternating current overvoltage protection circuit comprises a first rectifier module, a voltage division module, a switch control module and an alternating current relay module.

[0005] The first end of the first rectifier module is connected to the input end, the second end of the first rectifier module is connected to the first end of the voltage division module, the second end of the voltage division module is connected to the first end of the switch control module, the second end of the switch control module is connected to the first end of the alternating current relay module, the second end of the alternating current relay module is connected to the input end, and the third end of the alternating current relay module is connected to the output end.

[0006] When the voltage output by the second end of the voltage division module is greater than a preset threshold value, the switch control module is in a disconnected state, so that the third end of the alternating current relay module is disconnected from the output end.

[0007] When the voltage output by the second end of the voltage division module is less than or equal to the preset threshold value, the switch control module is in a conductive state, so that the third end of the alternating current relay module is connected to the output end.

[0008] In an embodiment of the present application, the alternating current overvoltage protection circuit further comprises a first voltage stabilizing and filtering module, the first end of the first voltage stabilizing and filtering module is connected to the second end of the voltage division module, and the second end of the first voltage stabilizing and filtering module is connected to the first end of the switch control module.

[0009] In an embodiment of the present application, the alternating overvoltage protection circuit further comprises a photocoupling control module, a second end of the switch control module is connected to a first end of the photocoupling control module, a second end of the photocoupling control module is connected to a first end of the alternating relay module, and a third end of the photocoupling control module is connected to the output end;

[0010] When the voltage output by the second end of the voltage dividing module is greater than a preset threshold value, the switch control module is in an off state, so that the photocoupling control module and the alternating relay module are not conductive, so that the third end of the alternating relay module is disconnected from the output end.

[0011] When the voltage output by the second end of the voltage dividing module is less than or equal to the preset threshold value, the switch control module is in a conductive state, so that the photocoupling control module and the alternating relay module are conductive, so that the third end of the alternating relay module is conductive with the output end.

[0012] In an embodiment of the present application, the switch control module comprises a first triode, a second triode, a first diode, a first voltage stabilizing diode, and a first resistor.

[0013] The base of the first triode is connected to the second end of the voltage dividing module, the emitter of the first triode is connected to the emitter of the second triode, the emitter of the first triode is also connected to the first end of the first resistor, the second end of the first resistor is connected to the base of the second triode, the collector of the first triode is connected to the negative electrode of the first diode, the positive electrode of the first diode is connected to the negative electrode of the first voltage stabilizing diode, the positive electrode of the first voltage stabilizing diode is connected between the second end of the first resistor and the base of the second triode, the collector of the second triode is connected to the first end of the photocoupling control module, and the positive electrode of the first diode and the negative electrode of the first voltage stabilizing diode are also connected to the fourth end of the photocoupling control module.

[0014] In an embodiment of the present application, the photocoupling control module comprises a photocoupling switch, a bidirectional thyristor, a second resistor, a third resistor, a first adjustable resistor, a second adjustable resistor, and a first capacitor.

[0015] The first end of the photocoupling switch is connected to the collector of the second triode, the second end of the photocoupling switch is connected to the positive electrode of the first diode and the negative electrode of the first voltage stabilizing diode, the third end of the photocoupling switch is connected to the control electrode of the bidirectional thyristor, the third end of the photocoupling switch is also connected to the first end of the second resistor, the second end of the second resistor is connected to the cathode of the bidirectional thyristor and then connected to the output end.

[0016] The fourth end of the light coupling switch is connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the first adjustable resistor, the second end of the first adjustable resistor is connected to the first end of the first capacitor, and the second end of the first capacitor is connected to the output end.

[0017] The anode of the bidirectional thyristor is connected to the first end of the second adjustable resistor, the second end of the second adjustable resistor is connected to the first end of the AC relay module, and the first end of the second adjustable resistor is also connected between the second end of the third resistor and the first end of the first adjustable resistor.

[0018] In an embodiment of the present application, the AC overvoltage protection circuit further comprises an alarm module and an AC-to-DC power supply module, the first end of the AC-to-DC power supply module is connected to the input end, the second end of the AC-to-DC power supply module is connected to the first end of the alarm module, and the second end of the alarm module is connected to the third end of the switch control module.

[0019] In an embodiment of the present application, when the voltage output by the second end of the voltage dividing module is greater than a preset threshold, the switch control module is turned on, so that the alarm module is turned on to issue an alarm; when the voltage output by the second end of the voltage dividing module is less than or equal to the preset threshold, the switch control module is turned off, so that the alarm module is not turned on and no alarm is issued.

[0020] In an embodiment of the present application, the AC overvoltage protection circuit comprises a second rectifier module, the first end of the second rectifier module is connected to the input end, and the second end of the second rectifier module is connected to the second end of the alarm module.

[0021] In an embodiment of the present application, the AC overvoltage protection circuit further comprises a second filter and voltage stabilizing module and / or a step-down module.

[0022] The first end of the second filter and voltage stabilizing module is connected to the second end of the second rectifier module, and the second end of the second filter and voltage stabilizing module is connected to the second end of the alarm module.

[0023] The first end of the step-down module is connected to the input end, and the second end of the step-down module is connected to the first end of the second rectifier module.

[0024] To achieve the above-mentioned purpose, a second aspect of the embodiments of the present application proposes a movie and television lamp comprising the AC overvoltage protection circuit according to any one of the embodiments of the present application.

[0025] In the technical scheme provided in the embodiment of the present application, the AC overvoltage protection circuit comprises a first rectifying module, a voltage dividing module, a switch control module and an AC relay module. When the voltage output by the second end of the voltage dividing module is greater than a preset threshold, the switch control module is in an open state, so that the third end of the AC relay module is disconnected from the output end, that is, the connection between the movie projector lamp and the AC power supply can be disconnected in the overvoltage state, so as to protect the movie projector lamp from damage due to overvoltage. When the voltage output by the second end of the voltage dividing module is less than or equal to the preset threshold, the switch control module is in a conductive state, so that the third end of the AC relay module is connected to the output end, that is, the movie projector lamp can be supplied with voltage from the AC power supply in the non-overvoltage state, so that the movie projector lamp can work normally. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 FIG. 1 is a first circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0027] Figure 2 FIG. 2 is a second circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0028] Figure 3 FIG. 3 is a third circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0029] Figure 4 FIG. 4 is a fourth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0030] Figure 5 FIG. 5 is a fifth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0031] Figure 6 FIG. 6 is a sixth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0032] Figure 7 FIG. 7 is a seventh circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0033] Figure 8 FIG. 8 is an eighth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0034] Figure 9 FIG. 9 is a ninth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0035] Figure 10 FIG. 10 is a circuit diagram of an AC overvoltage protection circuit provided by an embodiment of the present application.

[0036] BRIEF DESCRIPTION OF DRAWINGS

[0037] The first rectification module 10, the voltage division module 20, the switch control module 30, the optocoupler control module 40, the AC relay module 50, the filter module 60, the first voltage stabilization filter module 70, the alarm module 80, the AC-to-DC power supply module 90, the second rectification module 910, the second filter voltage stabilization module 920, the voltage reduction module 930, and the fuse 100. DETAILED DESCRIPTION

[0038] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0039] It should be noted that although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, 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 specification and claims and the above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0040] 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 the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0041] In the filming of films and television series, high-power film and television lamps are needed to create the light effect required by the scene. However, high-power film and television lamps usually need to be connected to an AC power supply for power supply. However, due to some differences in the standards and stability of power supply systems in different regions, there are cases where the voltage of the connected AC power supply is too high, and the high voltage will cause the film and television lamp to be damaged. Therefore, it is necessary to provide an AC overvoltage protection circuit to protect the film and television lamp.

[0042] Based on this, the embodiments of the present application provide an AC overvoltage protection circuit, which can control the circuit to be disconnected when the voltage of the connected AC power supply is too high, so as to protect the film and television lamp from being damaged due to overvoltage.

[0043] Reference Figure 1 , Figure 1 is a first circuit diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 1 , the AC overvoltage protection circuit has an input terminal J1 and an output terminal J2, the input terminal J1 is used to connect an AC power supply (AC), and the output terminal J2 is used to connect a film and television lamp. The AC overvoltage protection circuit includes a first rectification module 10, a voltage division module 20, a switch control module 30, and an AC relay module 50.

[0044] The first end of the first rectifier module 10 is connected to the input end J1, the second end of the first rectifier module 10 is connected to the first end of the voltage division module 20, the second end of the voltage division module 20 is connected to the first end of the switch control module 30, the second end of the switch control module 30 is connected to the first end of the alternating current relay module 50, the second end of the alternating current relay module 50 is connected to the input end J1, and the third end of the alternating current relay module 50 is connected to the output end J2.

[0045] The first end of the first rectifier module 10 is connected to the input end J1, that is, the first end of the first rectifier module 10 is connected to the alternating current power supply, so as to convert alternating current into direct current. In an alternating current system, the direction of voltage and current will change constantly, and the first rectifier module 10 can utilize the unidirectional conduction characteristic of a diode to make the current flow in only one direction, thereby converting alternating current into unidirectional pulsating direct current. The first rectifier module 10 can include a half-wave rectification circuit, a full-wave rectification circuit (such as a bridge-type full-wave rectification), and the like.

[0046] The voltage division module 20 is connected to the first rectifier module 10, and is configured to perform voltage division processing on the rectified output voltage of the first rectifier module 10. The voltage division module 20 can be a voltage division circuit. Specifically, the voltage division can be achieved by connecting resistors in series according to the resistance voltage division law and Ohm's law. In the voltage division circuit, two resistors are connected in series to form a resistance network, one of which is connected to the input voltage and the other is connected to the ground. The output voltage is a part of the input voltage, and its size depends on the resistance ratio of the two resistors. By adjusting the resistance value, the desired voltage division ratio can be achieved, thereby obtaining the required output voltage.

[0047] The second end of the alternating current relay module 50 is connected to the input end J1, that is, the alternating current relay module 50 is connected to the alternating current power supply, and the alternating current relay module 50 is powered by the alternating current power supply.

[0048] In the embodiment of the present application, it is considered that the voltage after voltage division by the voltage division module 20 can still be too high, thereby causing the video light to be damaged due to overvoltage. Therefore, the switch control module 30 and the alternating current relay module 50 need to be connected in sequence after the voltage division module 20, so that when the voltage output by the second end of the voltage division module 10 is greater than a preset threshold, the switch control module 30 is in an open state, so that the third end of the alternating current relay module 50 and the output end J2 are disconnected; that is, the connection between the video light and the alternating current power supply can be disconnected in an overvoltage state, so as to protect the video light from overvoltage and prevent the video light from being damaged due to overvoltage. When the voltage output by the second end of the voltage division module 20 is less than or equal to the preset threshold, the switch control module 30 is in a conduction state, so that the third end of the alternating current relay module 50 and the output end J2 are in conduction, that is, the video light can be supplied with voltage by the alternating current power supply in a non-overvoltage state, and the video light can work normally.

[0049] Referring toFigure 2 , Figure 2 is a second circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 2 , the AC overvoltage protection circuit comprises the first rectifier module 10, the voltage dividing module 20, the switch control module 30, the AC relay module 50, and further comprises a filter module 60. The first end of the filter module 60 is connected to the second end of the first rectifier module 10, and the second end of the filter module 60 is connected to the first end of the voltage dividing module 20. That is, the filter module 60 is connected between the first rectifier module 10 and the voltage dividing module 20. The filter module 60 can comprise a filter capacitor. The filter capacitor smoothes the AC signal through the charge and discharge process, removes the unwanted AC components, retains the DC components, and thus provides a stable DC output.

[0050] Referring to Figure 3 , Figure 3 is a third circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 3 , the AC overvoltage protection circuit comprises the first rectifier module 10, the filter module 60, the voltage dividing module 20, the switch control module 30, and the AC relay module 50, and further comprises a first voltage stabilizing filter module 70. The first end of the first voltage stabilizing filter module 70 is connected to the second end of the voltage dividing module 20, and the second end of the first voltage stabilizing filter module 70 is connected to the first end of the switch control module 30. That is, the first voltage stabilizing filter module 70 is connected between the voltage dividing module 20 and the switch control module 30. The first voltage stabilizing filter module 70 can comprise a voltage stabilizing part and a filter part. The voltage stabilizing part can comprise a voltage stabilizing diode, and is used to control the voltage fluctuation output by the voltage dividing module 20 within a certain range, to ensure that the output voltage remains stable. This avoids frequent switching of the circuit on or off due to voltage fluctuation. The filter part can comprise a resistor and a capacitor. The filter part is used to further remove the AC components and noise components output by the voltage dividing module 20, so that the output voltage is more stable. Specifically, the filter part can use the energy storage and release characteristics of the capacitor to filter the signal output by the voltage dividing module 20. The capacitor can be used to store electric charge, smooth voltage fluctuation, and in particular to filter out AC components and reduce the ripple of the output voltage. The resistor can be used to control the current or form an RC filter with the capacitor, thereby controlling the frequency response of the filter.

[0051] Referring to Figure 4 , Figure 4 is a fourth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 4As shown, the AC overvoltage protection circuit includes a first rectifier module 10, a filter module 60, a voltage divider module 20, a first voltage regulator and filter module 70, a switch control module 30, an AC relay module 50, and an optocoupler control module 40. The second terminal of the switch control module 30 is connected to the first terminal of the optocoupler control module 40, the second terminal of the optocoupler control module 40 is connected to the first terminal of the AC relay module 50, and the third terminal of the optocoupler control module 40 is connected to the output terminal J2. That is, the optocoupler control module 40 is connected between the switch control module 30 and the AC relay module 50, and is also connected to the output terminal J2. When the voltage output from the second terminal of the voltage divider module 10 exceeds a preset threshold, the switch control module 30 is in an open state, preventing the optocoupler control module 40 from conducting with the AC relay module 50, thus disconnecting the third terminal of the AC relay module 50 from the output terminal J2. This disconnects the video lamp from the AC power supply under overvoltage conditions, providing overvoltage protection for the video lamp and preventing damage due to overvoltage. When the voltage output from the second terminal of the voltage divider module 20 is less than or equal to a preset threshold, the switch control module 30 is in the conducting state, which makes the optocoupler control module 40 and the AC relay module 50 conduct, so that the third terminal of the AC relay module 50 is connected to the output terminal J2. In this way, the AC power supply can provide voltage to the film and television lamp in a non-overvoltage state, and the film and television lamp can work normally.

[0052] Reference Figure 5 , Figure 5 This is a fifth circuit block diagram of an AC overvoltage protection circuit provided in an embodiment of this application. Figure 5 As shown, the AC overvoltage protection circuit includes a first rectifier module 10, a filter module 60, a voltage divider module 20, a first voltage regulator and filter module 70, a switch control module 30, an optocoupler control module 40, and an AC relay module 50, as well as an alarm module 80 and an AC-to-DC power supply module 90. The first terminal of the AC-to-DC power supply module 90 is connected to the input terminal J1, used to connect to an external AC power source and convert AC to DC. The second terminal of the AC-to-DC power supply module 90 is connected to the first terminal of the alarm module 80, and the second terminal of the alarm module 80 is connected to the third terminal of the switch control module 30. The AC-to-DC power supply module 90 supplies power to the alarm module 80. When the voltage output from the second terminal of the voltage divider module 20 is greater than a preset threshold, the switch control module 30 can control the alarm module 80 to conduct, thus issuing an alarm. When the voltage output from the second terminal of the voltage divider module 20 is less than or equal to the preset threshold, the switch control module 30 can control the alarm module 80 to not conduct, thus not issuing an alarm. That is, through the settings of alarm module 80, an alarm can be issued in the case of overvoltage to indicate that the voltage connected to the video light is too high.

[0053] The alarm module 80 can include an audible alarm circuit or a light alarm circuit or an audible and light alarm circuit, that is, the alarm module 80 can adopt an audible alarm circuit, which can issue an audible alarm to remind the user of the overvoltage when the voltage output from the second end of the voltage dividing module 20 is too high. The alarm module 80 can also adopt a light alarm circuit, which can issue a light alarm (such as lighting or light flashing) to remind the user of the overvoltage when the voltage output from the second end of the voltage dividing module 20 is too high. The alarm module 80 can also adopt an audible and light alarm circuit, which can issue an audible and light alarm to remind the user of the overvoltage when the voltage output from the second end of the voltage dividing module 20 is too high.

[0054] With reference to Figure 6 , Figure 6 is a sixth circuit block diagram of an alternating current overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 6 , the alternating current overvoltage protection circuit includes the first rectifier module 10, the filter module 60, the voltage dividing module 20, the first voltage stabilizing and filtering module 70, the switch control module 30, the alarm module 80, the optocoupler control module 40, the alternating current relay module 50, and a second rectifier module 910. That is, the alternating current to direct current power supply module 90 includes the second rectifier module 910. The first end of the second rectifier module 910 is connected to the input end J1, and the second end of the second rectifier module 910 is connected to the second end of the alarm module 80.

[0055] In the embodiment of the present application, the second rectifier module 910 can be provided to connect to the input end J1, that is, to connect to the alternating current power supply, to convert the alternating current to direct current. The converted voltage is then transmitted to the alarm module 80 to provide a power supply voltage for the alarm module 80. Similarly, in the alternating current system, the direction of the voltage and the current will change constantly, and the second rectifier module 910 can utilize the unidirectional conduction characteristic of the diode to make the current flow in only one direction, thereby converting the alternating current to unidirectional pulsating direct current. The second rectifier module 910 can include a half-wave rectifier circuit, a full-wave rectifier circuit (such as a bridge-type full-wave rectifier), etc. By providing the second rectifier module 910 to convert the alternating current to direct current and then providing a power supply voltage for the alarm module 80, the working voltage for the alarm module 80 does not need to be provided by an additional power supply module, thereby saving costs.

[0056] With reference to Figure 7 , Figure 7 is a seventh circuit block diagram of an alternating current overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 7As shown, the AC overvoltage protection circuit comprises the first rectifying module 10, the filtering module 60, the voltage dividing module 20, the first voltage stabilizing and filtering module 70, the switch control module 30, the second rectifying module 910, the alarm module 80, the optocoupler control module 40, the AC relay module 50 and the second voltage stabilizing and filtering module 920. The second voltage stabilizing and filtering module 920 is connected between the second rectifying module 910 and the alarm module 80. The second voltage stabilizing and filtering module 920 provides a stable voltage for the alarm module 80. The second voltage stabilizing and filtering module 920 comprises a voltage stabilizing part and a filtering part. The voltage stabilizing part comprises a voltage stabilizing diode, which controls the voltage fluctuation of the second rectifying module 910 within a certain range, ensuring the stability of the output voltage. The filtering part comprises a resistor and a capacitor, which further removes the AC component and noise component of the output of the second rectifying module 910, making the output voltage more stable. Specifically, the filtering part uses the energy storage and release characteristics of the capacitor to filter the signal output by the second rectifying module 910. The capacitor is used to store electric charge and smooth voltage fluctuation, especially to filter out the AC component and reduce the ripple of the output voltage. The resistor is used to control the current or form an RC filter with the capacitor, thereby controlling the frequency response of the filter.

[0057] Referring to Figure 8 , Figure 8 is a seventh circuit diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown, the AC overvoltage protection circuit comprises the first rectifying module 10, the filtering module 60, the voltage dividing module 20, the first voltage stabilizing and filtering module 70, the switch control module 30, the second rectifying module 910, the alarm module 80, the optocoupler control module 40 and the AC relay module 50. The second rectifying module 910 is connected between the voltage dividing module 20 and the alarm module 80. The second rectifying module 910 provides a stable voltage for the alarm module 80. The second rectifying module 910 comprises a voltage stabilizing part and a filtering part. The voltage stabilizing part comprises a voltage stabilizing diode, which controls the voltage fluctuation of the second rectifying module 910 within a certain range, ensuring the stability of the output voltage. The filtering part comprises a resistor and a capacitor, which further removes the AC component and noise component of the output of the second rectifying module 910, making the output voltage more stable. Specifically, the filtering part uses the energy storage and release characteristics of the capacitor to filter the signal output by the second rectifying module 910. The capacitor is used to store electric charge and smooth voltage fluctuation, especially to filter out the AC component and reduce the ripple of the output voltage. The resistor is used to control the current or form an RC filter with the capacitor, thereby controlling the frequency response of the filter. Figure 8As shown, the AC overvoltage protection circuit comprises, in addition to the first rectifier module 10, the filter module 60, the voltage dividing module 20, the first voltage stabilizing filter module 70, the switch control module 30, the second rectifier module 910, the second filter voltage stabilizing module 920, the alarm module 80, the optocoupler control module 40 and the AC relay module 50, also comprises a voltage reducing module 930. That is, the AC-to-DC power supply module 90 can also comprise the voltage reducing module 930, wherein the first end of the voltage reducing module 930 is connected to the input end J1, and the second end of the voltage reducing module 930 is connected to the first end of the second rectifier module 910. The first end of the voltage reducing module 930 is connected to the input end J1, that is, the voltage reducing module 930 is used to connect the AC power supply, and is used to reduce the voltage of the AC power supply to a voltage range suitable for use by a specific circuit. That is, the embodiment of the present application considers that the voltage of the external AC power supply connected may be high, and the alarm module 80 works within a certain voltage range, therefore, the voltage reducing module 930 needs to be set to reduce the power supply of the AC power supply to a preset power supply range, and then provide it to the alarm module 80, which can ensure the normal work of the alarm module 80. The voltage reducing module 930 can comprise a resistance-capacitance voltage reducing circuit, a DC-DC voltage reducing circuit, etc. Among them, the resistance-capacitance voltage reducing circuit is composed of a series connection of a capacitor and a resistor, and the capacitive reactance of the capacitor limits the maximum working current in the circuit. The resistance-capacitance voltage reducing circuit uses the capacitive reactance generated by the capacitor under the AC signal to limit the maximum working current, thereby achieving the purpose of voltage reduction. Specifically, when the input voltage is applied to the voltage reducing module 930, the capacitor begins to charge, and the current passes through the resistor to generate a voltage drop, thereby reducing the output voltage. When the input voltage decreases, the capacitor begins to discharge, and the current passes through the resistor to generate a reverse voltage drop, further reducing the output voltage.

[0058] Referring to Figure 9 , Figure 9 is a ninth circuit block diagram of an AC overvoltage protection circuit provided by an embodiment of the present application. As shown, Figure 9 in addition to the first rectifier module 10, the filter module 60, the voltage dividing module 20, the first voltage stabilizing filter module 70, the switch control module 30, the voltage reducing module 930, the second rectifier module 910, the second filter voltage stabilizing module 920, the alarm module 80, the optocoupler control module 40 and the AC relay module 50, the AC overvoltage protection circuit also comprises a fuse 100. Among them, the first end of the fuse 100 is connected to the input end J1, the second end of the fuse 100 is connected to the first end of the first rectifier module 10, the second end of the fuse 100 is also connected to the first end of the voltage reducing module 930, and the second end of the fuse 100 is also connected to the second end of the AC relay module 50.

[0059] In an alternating current circuit, the fuse 100 is connected to the live wire, which can cut off the circuit when the current is overloaded or short-circuited, protecting the safety of electrical appliances (such as film and television lamps) and the circuit. The live wire is the active wire in the circuit, providing power to allow electrical appliances (such as film and television lamps) to operate normally. When an overload or short circuit occurs in the circuit, the current of the live wire will increase sharply, which can cause great harm to electrical appliances (such as film and television lamps) and electrical wires, and even cause a fire. Therefore, connecting the fuse 100 can cut off the circuit in the event of a fault, avoiding overheating of the electrical wires, causing a fire, or damaging the film and television lamps. In addition, the working principle of the fuse 100 is that when the current in the circuit is too large, the fuse in the fuse 100 will generate heat and melt, thereby disconnecting the circuit. This design allows the fuse 100 to only connect one fuse to the live wire, and when the fuse melts, it is disconnected from the live wire, preventing electric shock when the circuit is connected, thereby ensuring safety.

[0060] Referring to Figure 10 , Figure 10 is a circuit diagram of an alternating current overvoltage protection circuit provided by an embodiment of the present application. As shown in Figure 10 , the switch control module 30 includes a first triode Q6, a second triode Q7, a first diode D19, a first voltage stabilizing diode D24, and a first resistor R37. Among them, the base of the first triode Q6 is connected to the second end of the first voltage stabilizing filter module 70, the emitter of the first triode Q6 is connected to the emitter of the second triode Q7, the emitter of the first triode Q6 is also connected to the first end of the first resistor R37, the second end of the first resistor R37 is connected to the base of the second triode Q7, the collector of the first triode Q6 is connected to the negative electrode of the first diode D19, the positive electrode of the first diode D19 is connected to the negative electrode of the first voltage stabilizing diode D24, the positive electrode of the first voltage stabilizing diode D24 is connected between the second end of the first resistor R37 and the base of the second triode Q7, the collector of the second triode Q7 is connected to the first end of the optocoupler control module 40, and the positive electrode of the first diode D19 and the negative electrode of the first voltage stabilizing diode D24 are also connected to the fourth end of the optocoupler control module 40.

[0061] In the embodiment of the present application, when the voltage outputted by the second end of the voltage dividing module 20 is greater than the preset threshold, a high potential can be outputted to the base of the first triode Q6, so that the first triode Q6 is turned on, and the alarm module 80 is turned on to work and issue an alarm to prompt the overvoltage. Meanwhile, after the first triode Q6 is turned on, the first diode D19 is also turned on to pull down the reverse voltage of the first voltage stabilizing diode D24, so that the first voltage stabilizing diode D24 does not reach the reverse breakdown voltage and remains off, thus the base of the second triode Q7 is at a low potential, and the second triode Q7 is in an off state, so that the optocoupler control module 40 and the AC relay module 50 are not turned on, and thus the third end of the AC relay module 50 and the output end J2 are disconnected, that is, the connection between the movie projector lamp and the AC power supply can be disconnected in the overvoltage state, so as to protect the movie projector lamp from damage due to overvoltage. When the voltage outputted by the second end of the voltage dividing module 20 is less than or equal to the preset threshold, the base of the first triode Q6 is at a low potential and remains off, so that the alarm module 80 does not work. Meanwhile, when the first triode Q6 is off, the first diode D19 is cut off, and the first voltage stabilizing diode D24 is turned on in the reverse breakdown state, so that the base of the second triode Q7 is at a high potential, the second triode Q7 is turned on, and the optocoupler control module 40 and the AC relay module 50 are turned on, so that the third end of the AC relay module 50 and the output end J2 are connected. That is, the movie projector lamp can be supplied with voltage from the AC power supply in the non-overvoltage state, and the movie projector lamp can work normally.

[0062] With reference to Figure 10 The optocoupler control module 40 comprises an optocoupler switch U2, a bidirectional thyristor Q5, a second resistor R46, a third resistor R41, a first adjustable resistor R43, a second adjustable resistor R42, and a first capacitor C10. The first end of the optocoupler switch U2 is connected to the collector of the second triode Q7, the second end of the optocoupler switch U2 is connected to the anode of the first diode D19 and the cathode of the first voltage stabilizing diode D24, the third end of the optocoupler switch U2 is connected to the control electrode of the bidirectional thyristor Q5, and the third end of the optocoupler switch U2 is also connected to the first end of the second resistor R46, the second end of the second resistor R46 is connected to the cathode of the bidirectional thyristor Q5 and then connected to the output end J2. The fourth end of the optocoupler switch U2 is connected to the first end of the third resistor R41, the second end of the third resistor R41 is connected to the first end of the first adjustable resistor R43, the second end of the first adjustable resistor R43 is connected to the first end of the first capacitor C10, and the second end of the first capacitor C10 is connected to the output end J2. The anode of the bidirectional thyristor Q5 is connected to the first end of the second adjustable resistor R42, the second end of the second adjustable resistor R42 is connected to the first end of the AC relay module, and the first end of the second adjustable resistor R42 is also connected between the second end of the third resistor R41 and the first end of the first adjustable resistor R43.

[0063] In the embodiment of the present application, when the voltage outputted by the second end of the voltage dividing module 20 is greater than the preset threshold, a high potential can be outputted to the base of the first triode Q6, so that the first triode Q6 is turned on, and the alarm module 80 is turned on to work and issue an alarm to prompt that the voltage is too high. Meanwhile, after the first triode Q6 is turned on, the first diode D19 is also turned on to pull down the reverse voltage of the first stabilizing diode D24, so that the first stabilizing diode D24 does not reach the reverse breakdown voltage and remains off, so that the base of the second triode Q7 is at a low potential, the second triode Q7 is in an off state, the optocoupler switch U2 is off, the optocoupler control module 30 has no loop current, and the bidirectional thyristor Q5 is off, so that the coil in the alternating current relay in the alternating current relay module 50 is not powered, the third end of the alternating current relay module 50 is disconnected with the output end J2 (the moving contact 3 is closed with the stationary contact 2), and the movie projector lamp has no voltage supply. That is, the connection between the movie projector lamp and the alternating current power supply can be disconnected in the overvoltage state to protect the movie projector lamp from damage due to overvoltage. When the voltage outputted by the second end of the voltage dividing module 20 is less than or equal to the preset threshold, the base of the first triode Q6 is at a low potential and remains off, so that the alarm module 80 does not work. Meanwhile, when the first triode Q6 is off, the first diode D19 is cut off, and the first stabilizing diode D24 is turned on in the reverse breakdown state, so that the base of the second triode Q7 is at a high potential, the second triode Q7 is turned on, the optocoupler switch U2 is turned on, the optocoupler control module 30 generates a loop current, and the bidirectional thyristor Q5 is triggered to be turned on, so that the coil in the alternating current relay in the alternating current relay module 50 is powered, the third end of the alternating current relay module 50 is connected with the output end J2 (the moving contact 3 is closed with the stationary contact 1), and the movie projector lamp can work normally. That is, the movie projector lamp can be supplied with voltage by the alternating current power supply in the non-overvoltage state, and the movie projector lamp can work normally.

[0064] It should be noted that, Figure 10 The specific circuit structure corresponding to each module shown in the circuit diagram shown is only one example of the circuit structure of each module, and the circuit structure of each module in the present application is not limited to Figure 10 The circuit structure shown in the circuit diagram shown can also include other variations. For example, in addition to the three-contact relay shown in the alternating current relay module 50, Figure 10 Figure 10 The alternating current relay module 50 can also include a moving-contact (normally open) contact relay and a moving-break (normally closed) contact relay.

[0065] The application further provides a movie and television lamp comprising the AC overvoltage protection circuit.

[0066] The embodiments described in the application are used to more clearly illustrate the technical solutions of the application, and do not constitute a limitation on the technical solutions provided by the application. Those skilled in the art can know that, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the application are also applicable to similar technical problems.

[0067] Those skilled in the art can understand that the technical solutions shown in the drawings do not constitute a limitation on the embodiments of the application, and can include more or fewer steps than shown in the drawings, or combine certain steps or different steps.

[0068] The device embodiments described above are only schematic, and the units described as separate components can or can not be physically separate, that is, can be located in one place or distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiments.

[0069] Those skilled in the art can understand that all or some of the steps in the above disclosed method, the function modules / units in the system and the device can be implemented as software, firmware, hardware and their appropriate combinations.

[0070] The terms "first", "second", "third", "fourth" and the like (if any) in the specification of the application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0071] It should be understood that, in the application, "at least one" refers to one or more, and "multiple" refers to two or more. "And / or" is used to describe the association relationship of the associated objects, which means that there can be three relationships, for example, "A and / or B" can represent three cases of only A, only B, and A and B existing at the same time, wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c can represent a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, and c can be single or multiple.

[0072] In several embodiments provided in the application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the above units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed mutual ones can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0073] The units described above as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0074] In addition, each functional unit in each embodiment of the application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0075] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application, essentially or in other words, the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes multiple instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program storage media.

[0076] The preferred embodiments of the embodiments of the present application are described above with reference to the accompanying drawings, and are not limited to the scope of the embodiments of the present application. Any modifications, equivalent replacements and improvements 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 circuit, characterized by, The alternating current overvoltage protection circuit has an input end and an output end, the input end is used for connecting an alternating current power supply, and the output end is used for connecting a movie and television lamp. The first end of the first rectification module is connected to the input end, the second end of the first rectification module is connected to the first end of the voltage division module, the second end of the voltage division module is connected to the first end of the switch control module, the second end of the switch control module is connected to the first end of the alternating current relay module, the second end of the alternating current relay module is connected to the input end, and the third end of the alternating current relay module is connected to the output end. When the voltage output by the second end of the voltage division module is greater than a preset threshold value, the switch control module is in an open state, so that the third end of the alternating current relay module is disconnected from the output end. When the voltage output by the second end of the voltage division module is less than or equal to the preset threshold value, the switch control module is in a conductive state, so that the third end of the alternating current relay module is connected to the output end.

2. The AC overvoltage protection circuit of claim 1, wherein The alternating current overvoltage protection circuit further comprises a first voltage stabilizing and filtering module, the first end of the first voltage stabilizing and filtering module is connected to the second end of the voltage division module, and the second end of the first voltage stabilizing and filtering module is connected to the first end of the switch control module.

3. The AC overvoltage protection circuit of claim 1, wherein The alternating current overvoltage protection circuit further comprises a photo-coupler control module, the second end of the switch control module is connected to the first end of the photo-coupler control module, the second end of the photo-coupler control module is connected to the first end of the alternating current relay module, and the third end of the photo-coupler control module is connected to the output end. When the voltage output by the second end of the voltage division module is greater than a preset threshold value, the switch control module is in an open state, so that the photo-coupler control module and the alternating current relay module are not conductive, and the third end of the alternating current relay module is disconnected from the output end. When the voltage output by the second end of the voltage division module is less than or equal to the preset threshold value, the switch control module is in a conductive state, so that the photo-coupler control module and the alternating current relay module are conductive, and the third end of the alternating current relay module is connected to the output end.

4. The AC overvoltage protection circuit of claim 3, wherein The switch control module comprises a first triode, a second triode, a first diode, a first voltage stabilizing diode and a first resistor. The base of the first triode is connected to the second end of the voltage division module, the emitter of the first triode is connected to the emitter of the second triode, the emitter of the first triode is also connected to the first end of the first resistor, the second end of the first resistor is connected to the base of the second triode, the collector of the first triode is connected to the negative electrode of the first diode, the positive electrode of the first diode is connected to the negative electrode of the first voltage stabilizing diode, the positive electrode of the first voltage stabilizing diode is connected between the second end of the first resistor and the base of the second triode, the collector of the second triode is connected to the first end of the optocoupler control module, and the positive electrode of the first diode and the negative electrode of the first voltage stabilizing diode are also connected to the fourth end of the optocoupler control module.

5. The AC overvoltage protection circuit of claim 4, wherein, The optocoupler control module comprises an optocoupler switch, a bidirectional thyristor, a second resistor, a third resistor, a first adjustable resistor, a second adjustable resistor, and a first capacitor. The first end of the optocoupler switch is connected to the collector of the second triode, the second end of the optocoupler switch is connected to the positive electrode of the first diode and the negative electrode of the first voltage stabilizing diode, the third end of the optocoupler switch is connected to the control electrode of the bidirectional thyristor, the third end of the optocoupler switch is also connected to the first end of the second resistor, and the second end of the second resistor is connected to the cathode of the bidirectional thyristor and then connected to the output end together. The fourth end of the optocoupler switch is connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the first adjustable resistor, the second end of the first adjustable resistor is connected to the first end of the first capacitor, and the second end of the first capacitor is connected to the output end. The anode of the bidirectional thyristor is connected to the first end of the second adjustable resistor, the second end of the second adjustable resistor is connected to the first end of the AC relay module, and the first end of the second adjustable resistor is also connected between the second end of the third resistor and the first end of the first adjustable resistor.

6. The AC overvoltage protection circuit of claim 1, wherein The AC overvoltage protection circuit further comprises an alarm module and an AC-to-DC power supply module, the first end of the AC-to-DC power supply module is connected to the input end, the second end of the AC-to-DC power supply module is connected to the first end of the alarm module, and the second end of the alarm module is connected to the third end of the switch control module.

7. The AC overvoltage protection circuit of claim 6, wherein, When the voltage output by the second end of the voltage division module is greater than a preset threshold value, the switch control module is turned on, so that the alarm module is turned on to issue an alarm; when the voltage output by the second end of the voltage division module is less than or equal to the preset threshold value, the switch control module is turned off, so that the alarm module is not turned on and no alarm is issued.

8. The AC overvoltage protection circuit of claim 6, wherein, The AC-to-DC power supply module comprises a second rectifier module, the first end of the second rectifier module is connected to the input end, and the second end of the second rectifier module is connected to the second end of the alarm module.

9. The AC overvoltage protection circuit of claim 8, wherein, The AC-to-DC power supply module further comprises a second filter and voltage stabilizing module and / or a step-down module. The first end of the second filter and voltage stabilizing module is connected to the second end of the second rectifier module, and the second end of the second filter and voltage stabilizing module is connected to the second end of the alarm module. The first end of the second filter and voltage stabilizing module is connected to the second end of the second rectifier module, and the second end of the second filter and voltage stabilizing module is connected to the second end of the alarm module. The first end of the voltage reduction module is connected to the input end, and the second end of the voltage reduction module is connected to the first end of the second rectifier module.

10. A film and television light characterized by, The AC overvoltage protection circuit comprises the AC overvoltage protection circuit according to any one of claims 1-9.

Images