Dimming circuit for movie and television lamp, controller, movie and television lamp and movie and television lamp light system

Abstract

A dimming circuit for a film and television lamp, a controller, the film and television lamp and a film and television lighting system belong to the technical field of LEDs, and are connected with a light-emitting assembly, a master control circuit determines a working mode based on target brightness information, outputs a first PWM signal and a first level signal according to the target brightness information in a constant current mode, and outputs a second PWM signal and a second level signal according to the target brightness information; outputting a first PWM signal and a second PWM signal according to the target brightness information in a constant voltage mode; the working mode comprises a constant current mode and a constant voltage mode; the booster circuit is connected with input direct current and boosts the input direct current based on the first PWM signal so as to output power supply direct current; the switching circuit transmits power supply direct current flowing through the light-emitting component based on the first level signal or the second PWM signal; therefore, the dimming circuit can work in two working modes (a constant-voltage mode and a constant-current mode), the current of the power supply direct current is adjusted in the constant-voltage mode, the voltage of the power supply direct current is adjusted in the constant-current mode, and the dimming depth of the dimming circuit for the film and television lamp is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of film and television lighting, and in particular, relates to a dimming circuit, a controller, a film and television lamp, and a film and television lighting system for a film and television lamp. Background Art

[0002] Currently, most common LED drivers are analog chips. In actual use, the dimming function of analog chips is mainly divided into two categories: pulse width modulation (PWM) dimming and traditional analog dimming. Among them, the PWM dimming depth is mostly below 3000:1, and the analog dimming depth is even lower than 1000:1. Therefore, in the field of professional film and television lighting that pursues highly precise dimming control, existing LED drivers are difficult to meet the requirements of high dimming depth. Summary of the invention

[0003] The purpose of the present application is to provide a dimming circuit, a controller, a film and television lamp and a film and television lighting system for a film and television lamp, aiming to solve the problem of low dimming depth of existing LED drivers.

[0004] The embodiment of the present application provides a dimming circuit for a film and television lamp, which is connected to a light-emitting component and includes:

[0005] a main control circuit, configured to access target brightness information, determine an operating mode based on the target brightness information, output a first PWM signal and a first level signal according to the target brightness information in a constant current mode, and output the first PWM signal and a second PWM signal according to the target brightness information in a constant voltage mode; the operating modes include the constant current mode and the constant voltage mode;

[0006] A boost circuit, connected to the main control circuit and the light-emitting component, for receiving input direct current and boosting the input direct current based on the first PWM signal to output power supply direct current;

[0007] A switch circuit is connected to the main control circuit and the light-emitting component, and is used to transmit the power supply direct current flowing through the light-emitting component based on the first level signal or the second PWM signal.

[0008] In one of the embodiments, in the constant current mode, the duty cycle of the first PWM signal is positively correlated with the target brightness information; in the constant voltage mode, the duty cycle of the second PWM signal is positively correlated with the target brightness information;

[0009] Wherein, in the constant voltage mode, the duty cycle of the first PWM signal tends to a constant value.

[0010] In one embodiment, the dimming circuit for a movie light further includes:

[0011] A voltage detection circuit, connected to the boost circuit, the light-emitting component and the main control circuit, for sampling the voltage of the DC power supply to output a voltage sampling signal;

[0012] The main control circuit is specifically used to access the target brightness information, to determine the working mode based on the target brightness information, to output the first PWM signal and the first level signal according to the target brightness information in the constant current mode, and to output the first PWM signal and the second PWM signal according to the voltage sampling signal and the target brightness information in the constant voltage mode.

[0013] In one embodiment, the dimming circuit for a movie light further includes:

[0014] A first follower circuit, connected between the voltage detection circuit and the main control circuit, and used for following the voltage sampling signal;

[0015] The main control circuit is specifically used to access the target brightness information, to determine the working mode based on the target brightness information, to output the first PWM signal and the first level signal according to the target brightness information in the constant current mode, and to output the first PWM signal and the second PWM signal according to the following voltage sampling signal and the target brightness information in the constant voltage mode.

[0016] In one embodiment, the dimming circuit for a movie light further includes:

[0017] A current detection circuit, connected to the switch circuit and the main control circuit, for sampling the current of the DC power supply to output a current sampling signal;

[0018] The main control circuit is used to access the target brightness information, determine the working mode based on the target brightness information, output the first PWM signal and the first level signal according to the current sampling signal and the target brightness information in the constant current mode, and output the first PWM signal and the second PWM signal according to the target brightness information in the constant voltage mode.

[0019] In one embodiment, the dimming circuit for a movie light further includes:

[0020] A second follower circuit, connected between the current detection circuit and the main control circuit, and used for following the current sampling signal;

[0021] The main control circuit is used to access the target brightness information, determine the working mode based on the target brightness information, output the first PWM signal and the first level signal according to the following current sampling signal and the target brightness information in the constant current mode, and output the first PWM signal and the second PWM signal according to the target brightness information in the constant voltage mode.

[0022] In one embodiment, the main control circuit includes:

[0023] a control circuit, configured to access the target brightness information, enter a constant voltage mode in response to the target brightness information being less than or equal to a threshold, enter a constant current mode in response to the target brightness information being greater than a threshold, and output a third PWM signal and a second level signal according to the target brightness information in the constant current mode, and output the third PWM signal and a fourth PWM signal according to the target brightness information in the constant voltage mode;

[0024] A driving circuit is connected to the control circuit, the boost circuit and the switch circuit, and is used to enhance the third PWM signal and the second level signal to output the first PWM signal and the first level signal, or to enhance the third PWM signal and the fourth PWM signal to output the first PWM signal and the second PWM signal.

[0025] In one embodiment, the driving circuit, the boost circuit, the switch circuit and the light-emitting component are all multiple;

[0026] The control circuit is connected to the plurality of driving circuits, and is specifically used to access the target brightness information, enter a constant voltage mode in response to the target brightness information being less than or equal to a threshold, enter a constant current mode in response to the target brightness information being greater than a threshold, and output a plurality of the third PWM signals and a plurality of the second level signals according to the target brightness information in the constant current mode, and output a plurality of the third PWM signals and a plurality of fourth PWM signals according to the target brightness information in the constant voltage mode;

[0027] Each driving circuit is connected to each of the boosting circuits in a one-to-one correspondence, and is also connected to each of the switch circuits in a one-to-one correspondence.

[0028] In one embodiment, the control circuit includes a microprocessor;

[0029] The first general input and output terminal of the microprocessor and the second general input and output terminal of the microprocessor are used together as the target brightness information input terminal of the control circuit to input the target brightness information; the third general input and output terminal of the microprocessor is used as the third PWM signal output terminal of the control circuit, connected to the drive circuit to output the third PWM signal; the fourth general input and output terminal of the microprocessor is used as the fourth PWM signal output terminal of the control circuit and the second level signal output terminal of the control circuit, connected to the drive circuit to output the fourth PWM signal and the second level signal.

[0030] In one of the embodiments, the driving circuit includes a driver, a first resistor and a second resistor;

[0031] The A channel input terminal of the driver serves as the third PWM signal input terminal of the drive circuit, and is connected to the control circuit to input the third PWM signal; the B channel input terminal of the driver serves as the fourth PWM signal input terminal of the drive circuit and the second level signal input terminal of the drive circuit, and is connected to the control circuit to input the fourth PWM signal and the second level signal; the A channel output terminal of the driver is connected to the first end of the first resistor, and the second end of the first resistor serves as the first PWM signal output terminal of the drive circuit, and is connected to the boost circuit to output the first PWM signal; the B channel output terminal of the driver is connected to the first end of the second resistor, and the second end of the second resistor serves as the second PWM signal output terminal of the drive circuit and the first level signal output terminal of the drive circuit, and is connected to the switch circuit to output the second PWM signal and the first level signal.

[0032] In one embodiment, a dimming circuit for a movie light is connected to a control module:

[0033] The control module is connected to the main control circuit and is used to output a communication signal; the communication signal carries the target brightness information.

[0034] In one embodiment, the boost circuit includes a first inductor, a first field effect transistor and a diode;

[0035] The first end of the first inductor serves as an input DC power input end of the boost circuit to receive the input DC power; the second end of the first inductor, the positive electrode of the diode and the drain of the first field effect transistor are connected, and the negative electrode of the diode serves as a power supply DC power output end of the boost circuit and is connected to the light-emitting component to output the power supply DC power; the gate of the first field effect transistor serves as a first PWM signal input end of the boost circuit and is connected to the main control circuit to input the first PWM signal; the source of the first field effect transistor is connected to the power ground.

[0036] The embodiment of the present application further provides a controller for a cinema light, wherein the controller for a cinema light includes the above-mentioned dimming circuit for a cinema light.

[0037] The embodiment of the present application further provides a film and television light, which includes the dimming circuit and light-emitting component for film and television lights mentioned above.

[0038] The embodiment of the present application further provides a film and television lighting system, which includes the above-mentioned controller for film and television lights and film and television lights. The film and television lights are separately arranged from the controller, and the film and television lights include light-emitting components.

[0039] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the main control circuit determines the working mode based on the target brightness information. In the constant current mode, the main control circuit outputs the first PWM signal and the first level signal, and the boost circuit adjusts the voltage of the boost circuit based on the first PWM signal to adjust the brightness of the light-emitting component, thereby realizing analog dimming in the constant current mode; in the constant voltage mode, the main control circuit outputs the first PWM signal and the second PWM signal, and the switching circuit adjusts the power supply DC flowing through the light-emitting component according to the second PWM signal to adjust the brightness of the light-emitting component, thereby realizing PWM dimming in the constant voltage mode; therefore, the present application can work in two working modes (constant voltage mode and constant current mode), and in the constant voltage mode, the current of the power supply DC flowing through the light-emitting component is adjusted by the second PWM signal, and in the constant current mode, the voltage of the power supply DC flowing through the light-emitting component is adjusted by the first PWM signal, and the mixed use of the two modes can provide smoother and finer brightness changes, thereby improving the dimming depth of the dimming circuit used for film and television lights. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical application in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1A schematic diagram of a structure of a dimming circuit for a film and television lamp provided in one embodiment of the present application;

[0042] Figure 2 Another structural schematic diagram of a dimming circuit for a film and television lamp provided in an embodiment of the present application;

[0043] Figure 3 Another structural schematic diagram of a dimming circuit for a film and television lamp provided in an embodiment of the present application;

[0044] Figure 4 Another structural schematic diagram of a dimming circuit for a film and television lamp provided in an embodiment of the present application;

[0045] Figure 5 Another structural schematic diagram of a dimming circuit for a film and television lamp provided in an embodiment of the present application;

[0046] Figure 6 Another structural schematic diagram of a dimming circuit for a film and television lamp provided in an embodiment of the present application;

[0047] Figure 7 Another structural schematic diagram of a dimming circuit for a film and television lamp provided in an embodiment of the present application;

[0048] Figure 8 Another structural schematic diagram of a dimming circuit for a film and television lamp provided in an embodiment of the present application;

[0049] Fig. 9 A partial exemplary circuit schematic diagram of a dimming circuit for a movie light provided in one embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0051] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0052] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0054] Figure 1 The following is a schematic diagram of a dimming circuit for a movie light provided by an embodiment of the present application. For ease of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0055] The dimming circuit for the film and television lamp is connected to the light-emitting component 91 , and includes a main control circuit 10 , a boost circuit 20 and a switch circuit 30 .

[0056] The main control circuit 10 is used to access the target brightness information, determine the working mode based on the target brightness information, output a first pulse width modulation (PWM) signal and a first level signal according to the target brightness information in the constant current mode, and output a first PWM signal and a second PWM signal according to the target brightness information in the constant voltage mode; the working modes include the constant current mode and the constant voltage mode.

[0057] The boost circuit 20 is connected to the main control circuit 10 and the light emitting component 91, and is used for receiving the input direct current and boosting the input direct current based on the first PWM signal to output the power supply direct current.

[0058] The switch circuit 30 is connected to the main control circuit 10 and the light-emitting component 91, and is used to transmit the power supply DC flowing through the light-emitting component 91 based on the first level signal or the second PWM signal.

[0059] It can be understood that, the first level can be a high level or a low level.

[0060] It can be understood that, in the constant voltage mode, the duty cycle of the second PWM signal is associated with the target brightness information. In the constant current mode, the duty cycle of the first PWM signal is associated with the target brightness information.

[0061] In a specific implementation, the main control circuit 10 can preset a brightness threshold. If the target brightness information is less than or equal to the threshold, the main control circuit 10 determines that the current working mode is a constant voltage mode. If the target brightness information is greater than the threshold, the main control circuit 10 determines that the current working mode is a constant current mode. The threshold can be set according to actual needs.

[0062] In a specific implementation, the target brightness information may be any value between 0 and 100%.

[0063] The main control circuit 10 compares the received target brightness information with a threshold value X% (X is any value between 0 and 100). If the target brightness information is greater than the threshold value X%, the main control circuit 10 enters a constant current mode, and calculates the initial duty cycle of the first PWM signal based on the target brightness information, and then outputs the first PWM signal and the first level signal. The boost circuit 20 outputs a power supply DC based on the first PWM signal, and the switch circuit 30 transmits the power supply DC flowing through the light-emitting component 91 based on the first level signal, and the light-emitting component 91 emits light based on the power supply DC. If the target brightness information is less than the threshold value X%, the main control circuit 10 enters a constant voltage mode, and calculates the initial duty cycle of the first PWM signal and the initial duty cycle of the second PWM signal based on the target brightness information, and then outputs the first PWM signal and the second PWM signal. The boost circuit 20 outputs a power supply DC with a constant voltage based on the first PWM signal, and the switch circuit 30 transmits the power supply DC flowing through the light-emitting component 91 based on the second PWM signal, and the light-emitting component 91 emits light based on the power supply DC. Therefore, the present application can flexibly choose to dim the light by changing the voltage of the supply DC power through the first PWM signal or by changing the current of the supply DC power through the second PWM signal according to the target brightness of the light-emitting component 91, thereby improving the dimming depth of the dimming circuit used for film and television lights.

[0064] As an example but not a limitation, in the constant current mode, the duty cycle of the first PWM signal is positively correlated with the target brightness information; in the constant voltage mode, the duty cycle of the second PWM signal is positively correlated with the target brightness information;

[0065] In the constant voltage mode, the duty cycle of the first PWM signal tends to be constant.

[0066] It should be noted that, theoretically, the duty cycle of the first PWM signal should be a constant value in the constant voltage mode. However, in actual applications, due to factors such as parasitic capacitance and parameter errors of various components, the duty cycle of the first PWM signal will fluctuate around a constant value. Therefore, the duty cycle of the first PWM signal is actually in a preset range.

[0067] In a specific implementation, in the constant current mode, the duty cycle of the first PWM signal increases, the voltage of the DC power output by the boost circuit 20 increases, and the brightness of the light-emitting component 91 increases, so the duty cycle of the first PWM signal is positively correlated with the target brightness information.

[0068] In a specific implementation, in the constant voltage mode, the duty cycle of the second PWM signal increases, the conduction time of the switch circuit 30 is prolonged, the current of the DC power supply flowing through the light-emitting component 91 increases, and the brightness of the light-emitting component 91 increases, so the duty cycle of the second PWM signal is positively correlated with the target brightness information.

[0069] The brightness of the light-emitting component 91 is adjusted by adjusting the duty cycle of the first PWM signal and the duty cycle of the second PWM signal, thereby improving the flexibility of brightness adjustment.

[0070] By way of example and not limitation, Figure 2 As shown, the dimming circuit for a movie light further includes a voltage detection circuit 40 .

[0071] The voltage detection circuit 40 is connected to the boost circuit 20, the light emitting component 91 and the main control circuit 10, and is used to perform voltage sampling on the supply DC power to output a voltage sampling signal.

[0072] The main control circuit 10 is specifically used to access the target brightness information, to determine the working mode based on the target brightness information, to output the first PWM signal and the first level signal according to the target brightness information in the constant current mode, and to output the first PWM signal and the second PWM signal according to the voltage sampling signal and the target brightness information in the constant voltage mode.

[0073] In the constant voltage mode, the main control circuit 10 outputs a first PWM signal according to the target brightness information to control the boost circuit 20 to boost the voltage so as to output the power supply DC. The voltage detection circuit 40 samples the voltage of the power supply DC and outputs the voltage sampling signal to the main control circuit 10. The main control circuit 10 outputs a first PWM signal after feedback adjustment according to the voltage sampling signal. The boost circuit 20 then outputs the power supply DC after feedback adjustment according to the first PWM signal after feedback adjustment, thereby establishing a feedback adjustment path for the power supply DC voltage so that the voltage of the voltage sampling signal is stabilized at a first preset value corresponding to the target brightness information.

[0074] In a specific implementation, in the constant voltage mode, if the current of the DC power supply is Ix, the main control circuit 10 can adjust the duty cycle (n%) of the second PWM signal based on the target brightness information. At this time, the current of the DC power supply will be adjusted to Ix*n%, and Ix*n% is the target current corresponding to the target brightness information at this time, thereby realizing PWM dimming in the constant voltage mode.

[0075] In a complex working environment, the dimming circuit used for film and television lights may be subject to a lot of external interference. The voltage detection circuit 40 can sample the voltage of the supply DC power in real time, and dynamically adjust the first PWM signal through the main control circuit 10, thereby dynamically adjusting the voltage of the supply DC power, thereby enhancing the stability of the dimming circuit used for film and television lights.

[0076] By way of example and not limitation, Figure 3 As shown, a first follower circuit 50 is also included.

[0077] The first follower circuit 50 is connected between the voltage detection circuit 40 and the main control circuit 10 and is used for following the voltage sampling signal.

[0078] The main control circuit 10 is specifically used to access the target brightness information, to determine the working mode based on the target brightness information, to output the first PWM signal and the first level signal according to the target brightness information in the constant current mode, and to output the first PWM signal and the second PWM signal according to the following voltage sampling signal and the target brightness information in the constant voltage mode.

[0079] The voltage sampling signal is followed by the first follower circuit 50 , thereby improving the stability of the voltage sampling signal.

[0080] By way of example and not limitation, Figure 4 As shown, the dimming circuit for a movie light further includes a current detection circuit 60 .

[0081] The current detection circuit 60 is connected to the switch circuit 30 and the main control circuit 10, and is used to sample the current of the DC power supply to output a current sampling signal.

[0082] The main control circuit 10 is used to access the target brightness information, determine the working mode based on the target brightness information, output the first PWM signal and the first level signal according to the current sampling signal and the target brightness information in the constant current mode, and output the first PWM signal and the second PWM signal according to the target brightness information in the constant voltage mode.

[0083] In the constant current mode, the main control circuit 10 outputs a first PWM signal according to the target brightness information to control the boost circuit 20 to boost the input DC power to output the power supply DC power. The current detection circuit 60 samples the current of the power supply DC power and outputs a current sampling signal to the main control circuit 10. The main control circuit 10 outputs a first PWM signal after feedback adjustment based on the current sampling signal. The boost circuit 20 then outputs the power supply DC power after feedback adjustment according to the first PWM signal after feedback adjustment, thereby establishing a feedback adjustment path for the power supply DC power current so that the voltage of the current sampling signal is stabilized at a second preset value corresponding to the target brightness information.

[0084] In a specific implementation, in the constant current mode, the main control circuit 10 determines the relationship between the current current Ia and the target current Iy corresponding to the target brightness information based on the current sampling signal. If the current current Ia is greater than the target current Iy, the main control circuit 10 reduces the duty cycle of the first PWM signal, so that the voltage of the supply DC power drops, and the current current Ia drops to the target current Iy; if the current current Ia is less than the target current Iy, the main control circuit 10 increases the duty cycle of the first PWM signal, so that the voltage of the supply DC power rises, and the current current Ia increases to the target current Iy.

[0085] The stability of the dimming circuit for the movie lamp is enhanced by the current detection circuit 60 .

[0086] By way of example and not limitation, Figure 5 As shown, the dimming circuit for a movie light further includes a second follower circuit 70 .

[0087] The second follower circuit 70 is connected between the current detection circuit 60 and the main control circuit 10 and is used for following the current sampling signal.

[0088] The main control circuit 10 is used to access the target brightness information, determine the working mode based on the target brightness information, output the first PWM signal and the first level signal according to the following current sampling signal and the target brightness information in the constant current mode, and output the first PWM signal and the second PWM signal according to the target brightness information in the constant voltage mode.

[0089] The second follower circuit 70 follows the current sampling signal, thereby improving the stability of the current sampling signal.

[0090] By way of example and not limitation, Figure 6 As shown, the main control circuit 10 includes a control circuit 11 and a drive circuit 12 .

[0091] The control circuit 11 is used to access the target brightness information, enter the constant voltage mode in response to the target brightness information being less than or equal to the threshold, enter the constant current mode in response to the target brightness information being greater than the threshold, and output the third PWM signal and the second level signal according to the target brightness information in the constant current mode, and output the third PWM signal and the fourth PWM signal according to the target brightness information in the constant voltage mode.

[0092] The driving circuit 12 is connected to the control circuit 11, the boost circuit 20 and the switch circuit 30, and is used to enhance the third PWM signal and the second level signal to output the first PWM signal and the first level signal, or to enhance the third PWM signal and the fourth PWM signal to output the first PWM signal and the second PWM signal.

[0093] It is understandable that drive circuits 12 of different specifications can be selected according to actual needs to adapt to usage scenarios of different powers.

[0094] The driving circuit 12 enhances the driving capability of the control circuit 11, thereby ensuring the normal operation of the dimming circuit for the film and television lamp.

[0095] By way of example and not limitation, Figure 7 As shown, the driving circuit 12 , the boost circuit 20 , the switch circuit 30 and the light emitting component 91 are all multiple.

[0096] The control circuit 11 is connected to multiple driving circuits 12, and is specifically used to access target brightness information, enter a constant voltage mode in response to the target brightness information being less than or equal to a threshold, enter a constant current mode in response to the target brightness information being greater than the threshold, and output multiple third PWM signals and multiple second level signals according to the target brightness information in the constant current mode, and output multiple third PWM signals and multiple fourth PWM signals according to the target brightness information in the constant voltage mode.

[0097] Each driving circuit 12 is connected to each boosting circuit 20 in a one-to-one correspondence, and is also connected to each switching circuit 30 in a one-to-one correspondence.

[0098] It should be noted that the driving frequency of the driving circuit 12 can be as high as 200 kHz.

[0099] Multi-channel control is achieved through one control circuit 11, which simplifies circuit design and reduces costs.

[0100] By way of example and not limitation, Figure 8 As shown, the dimming circuit for the movie light further includes a control module 80 .

[0101] The control module 80 is connected to the main control circuit 10 and is used to output a communication signal; the communication signal carries target brightness information.

[0102] In a specific implementation, the communication signal may be a serial communication signal or a wireless communication signal. Further, the serial communication signal may use USART for serial communication.

[0103] The control module 80 is programmable, so that different target brightness information can be set according to actual needs, thereby improving the flexibility of use.

[0104] Fig. 9 A partial exemplary circuit structure of a dimming circuit for a movie light provided in an embodiment of the present application is shown. For ease of description, only the part related to the embodiment of the present application is shown, which is described in detail as follows:

[0105] The control circuit 11 includes a microprocessor U1.

[0106] The first general input and output terminal PB5 of the microprocessor U1 and the second general input and output terminal PB6 of the microprocessor U1 are jointly used as the target brightness information input terminal of the control circuit 11 to input the target brightness information; the third general input and output terminal PA9 of the microprocessor U1 is used as the third PWM signal output terminal of the control circuit 11, connected to the drive circuit 12 to output the third PWM signal; the fourth general input and output terminal PA10 of the microprocessor U1 is used as the fourth PWM signal output terminal of the control circuit 11 and the second level signal output terminal of the control circuit 11, connected to the drive circuit 12 to output the fourth PWM signal and the second level signal; the fifth general input and output terminal PA3 of the microprocessor U1 is used as the voltage sampling signal input terminal of the control circuit 11, connected to the first follower circuit 50, to input the voltage sampling signal after following; the sixth general input and output terminal PA4 of the microprocessor U1 is used as the current sampling signal input terminal of the control circuit 11, connected to the second follower circuit 70, to input the current sampling signal after following.

[0107] The microprocessor U1 adopts a modular design and is easy to integrate with other components, thereby improving the flexibility and scalability of the dimming circuit for film and television lamps and simplifying the design of the hardware circuit.

[0108] The driving circuit 12 includes a driver U2 , a first resistor R1 , and a second resistor R2 .

[0109] The A channel input terminal INA of the driver U2 serves as the third PWM signal input terminal of the driving circuit 12, and is connected to the control circuit 11 to input the third PWM signal; the B channel input terminal INB of the driver U2 serves as the fourth PWM signal input terminal of the driving circuit 12 and the second level signal input terminal of the driving circuit 12, and is connected to the control circuit 11 to input the fourth PWM signal and the second level signal; the A channel output terminal OUTA of the driver U2 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 serves as the first PWM signal output terminal of the driving circuit 12, and is connected to the boost circuit 20 to output the first PWM signal; the B channel output terminal OUTB of the driver U2 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 serves as the second PWM signal output terminal of the driving circuit 12 and the first level signal output terminal of the driving circuit 12, and is connected to the switch circuit 30 to output the second PWM signal and the first level signal.

[0110] The circuit is simple and reliable.

[0111] Among them, the microprocessor U1 can be used to detect voltage and current and has high PWM modulation accuracy, but its voltage resistance and output current are relatively limited; the driver U2 has a high voltage resistance and can output a large current. Therefore, the combination of the two not only ensures the driving ability of the dimming circuit, but also broadens the application scope of the dimming circuit for film and television lamps, while taking into account the voltage and current detection functions and PWM modulation accuracy.

[0112] The boost circuit 20 includes a first inductor L1 , a first field effect transistor Q1 , and a diode D1 .

[0113] The first end of the first inductor L1 serves as the DC input terminal of the boost circuit 20 to receive the input DC power; the second end of the first inductor L1, the anode of the diode D1 and the drain of the first field effect transistor Q1 are connected, and the cathode of the diode D1 serves as the DC power output terminal of the boost circuit 20 and is connected to the light-emitting component 91 to output the DC power; the gate of the first field effect transistor Q1 serves as the first PWM signal input terminal of the boost circuit 20 and is connected to the main control circuit 10 to input the first PWM signal; the source of the first field effect transistor Q1 is connected to the power ground.

[0114] The circuit has a simple structure and high conversion efficiency.

[0115] The switch circuit 30 includes a second field effect transistor Q2.

[0116] The gate of the second field effect transistor Q2 serves as the first level signal input terminal of the switching circuit 30 and the second PWM signal input terminal of the switching circuit 30, and is connected to the main control circuit 10 to input the first level signal and the second PWM signal; the drain of the second field effect transistor Q2 serves as the input terminal of the power supply DC, and is connected to the light-emitting component 91 to input the power supply DC; the source of the second field effect transistor Q2 serves as the output terminal of the power supply DC, and is connected to the current detection circuit 60 and the second follower circuit 70 to output the power supply DC.

[0117] The voltage detection circuit 40 includes a third resistor R3 and a fourth resistor R4.

[0118] The first end of the third resistor R3 serves as the DC power input terminal of the voltage detection circuit 40, and is connected to the boost circuit 20 and the light-emitting component 91 to input the DC power supply; the second end of the third resistor R3 and the first end of the fourth resistor R4 serve together as the voltage sampling signal output terminal of the voltage detection circuit 40, and are connected to the first follower circuit 50 to output the voltage sampling signal; the second end of the fourth resistor R4 is connected to the power ground.

[0119] The first follower circuit 50 includes a first operational amplifier M1 .

[0120] The non-phase input terminal of the first operational amplifier M1 serves as the voltage sampling signal input terminal of the first follower circuit 50, and is connected to the voltage detection circuit 40 to input the voltage sampling signal; the inverting input terminal of the first operational amplifier M1 and the output terminal of the first operational amplifier M1 serve together as the output terminal of the voltage sampling signal after following the first follower circuit 50, and are connected to the main control circuit 10 to output the voltage sampling signal after following.

[0121] The current detection circuit 60 includes a fifth resistor R5 .

[0122] The first end of the fifth resistor R5 serves as the power supply DC input terminal and the current sampling signal output terminal of the current detection circuit 60, and is connected to the switch circuit 30 and the second follower circuit 70 to input the power supply DC and output the current sampling signal. The second end of the fifth resistor R5 is connected to the power ground.

[0123] The second follower circuit 70 includes a second operational amplifier M2 .

[0124] The non-inverting input terminal of the second operational amplifier M2 serves as the current sampling signal input terminal of the first follower circuit 50, and is connected to the current detection circuit 60 to input the current sampling signal; the inverting input terminal of the second operational amplifier M2 and the output terminal of the second operational amplifier M2 serve together as the current sampling signal output terminal after following the first follower circuit 50, and are connected to the main control circuit 10 to output the current sampling signal after following.

[0125] The light emitting assembly 91 includes a first light emitting diode LED1 and a second light emitting diode LED2.

[0126] The positive electrode of the first light-emitting diode LED1 serves as the DC power input terminal of the light-emitting component 91, and is connected to the boost circuit 20 and the voltage detection circuit 40 to input the DC power supply; the negative electrode of the first light-emitting diode LED1 is connected to the positive electrode of the second light-emitting diode LED2, and the negative electrode of the second light-emitting diode LED2 serves as the DC power output terminal of the light-emitting component 91, and is connected to the switching circuit 30 to output the DC power supply.

[0127] The dimming circuit for the film and television lamp further includes a first capacitor C1, and the first capacitor C1 is used for filtering the input direct current to improve the stability of the dimming circuit for the film and television lamp.

[0128] A first end of the first capacitor is connected to the first power source and the boost circuit 20 , and a second end of the first capacitor is connected to the power ground.

[0129] The dimming circuit for the movie light further includes a second capacitor C2, and the second capacitor C2 is used for filtering the supply DC power to improve the stability of the dimming circuit for the movie light.

[0130] A first end of the second capacitor C2 is connected to the boost circuit 20 , the voltage detection circuit 40 and the light emitting component 91 , and a second end of the second capacitor C2 is connected to the power ground.

[0131] The following is a combination of working principles Fig. 9 As shown for further explanation:

[0132] The control module 80 outputs a communication signal carrying target brightness information to the first general input / output terminal PB5 of the microprocessor U1 and the second general input / output terminal PB6 of the microprocessor U1 , and the microprocessor U1 determines the working mode according to the target brightness information.

[0133] If the target brightness information is less than or equal to the threshold, the microprocessor U1 enters the constant voltage mode. The microprocessor U1 outputs a third PWM signal with a constant duty cycle from the third general input / output terminal PA9 to the A channel input terminal INA of the driver U2 according to the voltage sampling signal and the target brightness information. The driver U2 enhances the third PWM signal, and outputs the first PWM signal with a constant duty cycle to the gate of the first field effect transistor Q1 through the second end of the first resistor R1. The first end of the first inductor L1 is connected to the input DC power. The first inductor L1, the first diode D1 and the first field effect transistor Q1 form a boost circuit 20. The boost circuit 20 converts the input DC power into a power supply DC power with a constant voltage based on the first PWM signal, and outputs the power supply DC power from the negative electrode of the diode D1. The first end of the third resistor R3 is connected to the power supply DC power. The third resistor R3 and the fourth resistor R4 divide the power supply DC power, and output the voltage sampling signal from the second end of the third resistor R3 and the first end of the fourth resistor R4 to the non-inverting input terminal of the first operational amplifier M1. The first operational amplifier M1 follows the voltage sampling signal and outputs the voltage sampling signal from the inverting input terminal of the first operational amplifier M1 and the first operational amplifier M1. The output end of an operational amplifier M1 jointly outputs the following voltage sampling signal to the fifth general input and output terminal PA3 of the microprocessor U1. The microprocessor U1 ensures that the voltage of the power supply DC is a constant value through the feedback of the voltage sampling signal; the positive electrode of the first light-emitting diode LED1 is connected to the power supply DC, and the negative electrode of the second light-emitting diode LED2 outputs the power supply DC to the drain of the second field effect transistor Q2; the microprocessor U1 also outputs a fourth PWM signal from the fourth general input and output terminal PA10 of the microprocessor U1 to the B channel input terminal INB of the driver U2, the driver U2 enhances the fourth PWM signal, and outputs the second PWM signal to the gate of the second field effect transistor Q2 through the second end of the second resistor R2, the second field effect transistor Q2 transmits the power supply DC based on the second PWM signal, and the current of the power supply DC is Ix at this time. The microprocessor U1 adjusts the duty cycle (n%) of the fourth PWM signal based on the target brightness information, and the current of the power supply DC will be adjusted to Ix*n%, and Ix*n% is the target current corresponding to the target brightness information at this time.

[0134] If the target brightness information is greater than or equal to the threshold, the microprocessor U1 enters the constant current mode. Based on the target brightness information, the microprocessor U1 outputs a third PWM signal from the third general input and output terminal PA9 of the microprocessor U1 to the A channel input terminal INA of the driver U2. The driver U2 enhances the third PWM signal and outputs the first PWM signal to the gate of the first field effect transistor Q1 through the second end of the first resistor R1. The boost circuit 20 converts the input DC power into the power supply DC power based on the first PWM signal. The positive electrode of the first light-emitting diode LED1 is connected to the power supply DC power, and the negative electrode of the second light-emitting diode LED2 outputs the power supply DC power to the drain of the second field effect transistor Q2. The fourth general input and output terminal PA10 of the microprocessor U1 outputs a high-level second-level signal to the B channel input terminal INB of the driver U2. The driver U2 enhances the second-level signal and outputs a high-level first-level signal from the B channel output terminal OUTB of the driver U2 to the gate of the second field effect transistor Q2. The second field effect transistor Q2 transmits the power supply DC power to the gate of the second field effect transistor Q2 based on the high-level power supply DC power. The first end of the fifth resistor R5, the fifth resistor R5 samples the current of the power supply DC, and outputs a current sampling signal from the first end of the fifth resistor R5 to the non-inverting input end of the second operational amplifier M2, the second operational amplifier M2 follows the current sampling signal, and outputs the followed current sampling signal from the inverting input end of the second operational amplifier M2 and the output end of the second operational amplifier M2 to the sixth general input and output end PA4 of the microprocessor U1, the microprocessor U1 determines the relationship between the current current Ia and the target current Iy corresponding to the target brightness information according to the followed current sampling signal, if the current current Ia is greater than the target current Iy, the microprocessor U1 reduces the duty cycle of the third PWM signal, so that the power supply DC voltage drops, and the current current Ia drops to the target current Iy, if the current current Ia is less than the target current Iy, the microprocessor U1 increases the duty cycle of the third PWM signal, so that the power supply DC voltage rises, and the current current Ia increases to the target current Iy.

[0135] The embodiment of the present application further provides a controller for a movie light, and the controller for a movie light includes the above-mentioned dimming circuit for a movie light.

[0136] The embodiment of the present application further provides a film and television light, which includes the dimming circuit and light-emitting component for film and television lights mentioned above.

[0137] The embodiment of the present application also provides a film and television lighting system, which includes the above-mentioned controller for film and television lights and film and television lights. The film and television lights are separately arranged from the controller, and the film and television lights include light-emitting components.

[0138] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0139] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A dimming circuit for a film and television lamp, characterized in that: Connect with the light emitting component, including: a main control circuit, configured to access target brightness information, determine an operating mode based on the target brightness information, output a first PWM signal and a first level signal according to the target brightness information in a constant current mode, and output the first PWM signal and a second PWM signal according to the target brightness information in a constant voltage mode; the operating modes include the constant current mode and the constant voltage mode; A boost circuit, connected to the main control circuit and the light-emitting component, for receiving input direct current and boosting the input direct current based on the first PWM signal to output power supply direct current; A switch circuit is connected to the main control circuit and the light-emitting component, and is used to transmit the power supply direct current flowing through the light-emitting component based on the first level signal or the second PWM signal.

2. The dimming circuit for a movie light according to claim 1, characterized in that: In the constant current mode, the duty cycle of the first PWM signal is positively correlated with the target brightness information; in the constant voltage mode, the duty cycle of the second PWM signal is positively correlated with the target brightness information; Wherein, in the constant voltage mode, the duty cycle of the first PWM signal tends to a constant value.

3. The dimming circuit for a movie light according to claim 1, characterized in that: Also includes: A voltage detection circuit, connected to the boost circuit, the light-emitting component and the main control circuit, for sampling the voltage of the power supply DC to output a voltage sampling signal; The main control circuit is specifically used to access the target brightness information, to determine the working mode based on the target brightness information, to output the first PWM signal and the first level signal according to the target brightness information in the constant current mode, and to output the first PWM signal and the second PWM signal according to the voltage sampling signal and the target brightness information in the constant voltage mode.

4. The dimming circuit for a movie light as claimed in claim 3, characterized in that: Also includes: A first follower circuit, connected between the voltage detection circuit and the main control circuit, and used for following the voltage sampling signal; The main control circuit is specifically used to access the target brightness information, to determine the working mode based on the target brightness information, to output the first PWM signal and the first level signal according to the target brightness information in the constant current mode, and to output the first PWM signal and the second PWM signal according to the following voltage sampling signal and the target brightness information in the constant voltage mode.

5. The dimming circuit for a movie light according to claim 1, characterized in that: Also includes: A current detection circuit, connected to the switch circuit and the main control circuit, for sampling the current of the DC power supply to output a current sampling signal; The main control circuit is used to access the target brightness information, determine the working mode based on the target brightness information, output the first PWM signal and the first level signal according to the current sampling signal and the target brightness information in the constant current mode, and output the first PWM signal and the second PWM signal according to the target brightness information in the constant voltage mode.

6. The dimming circuit for a movie light as claimed in claim 5, characterized in that: Also includes: A second follower circuit, connected between the current detection circuit and the main control circuit, and used for following the current sampling signal; The main control circuit is used to access the target brightness information, determine the working mode based on the target brightness information, output the first PWM signal and the first level signal according to the following current sampling signal and the target brightness information in the constant current mode, and output the first PWM signal and the second PWM signal according to the target brightness information in the constant voltage mode.

7. The dimming circuit for a movie light as claimed in claim 1, characterized in that: The main control circuit comprises: a control circuit, configured to access the target brightness information, enter a constant voltage mode in response to the target brightness information being less than or equal to a threshold, enter a constant current mode in response to the target brightness information being greater than a threshold, and output a third PWM signal and a second level signal according to the target brightness information in the constant current mode, and output the third PWM signal and a fourth PWM signal according to the target brightness information in the constant voltage mode; A driving circuit is connected to the control circuit, the boost circuit and the switch circuit, and is used to enhance the third PWM signal and the second level signal to output the first PWM signal and the first level signal, or to enhance the third PWM signal and the fourth PWM signal to output the first PWM signal and the second PWM signal.

8. The dimming circuit for a movie light as claimed in claim 7, characterized in that: The driving circuit, the boost circuit, the switch circuit and the light-emitting component are all multiple; The control circuit is connected to the plurality of driving circuits, and is specifically used to access the target brightness information, enter a constant voltage mode in response to the target brightness information being less than or equal to a threshold, enter a constant current mode in response to the target brightness information being greater than a threshold, and output a plurality of the third PWM signals and a plurality of the second level signals according to the target brightness information in the constant current mode, and output a plurality of the third PWM signals and a plurality of fourth PWM signals according to the target brightness information in the constant voltage mode; Each driving circuit is connected to each of the boosting circuits in a one-to-one correspondence, and is also connected to each of the switch circuits in a one-to-one correspondence.

9. The dimming circuit for a movie light according to any one of claims 1 to 8, characterized in that: The control circuit includes a microprocessor; The first general purpose input and output terminal of the microprocessor and the second general purpose input and output terminal of the microprocessor are used together as the target brightness information input terminal of the control circuit to input the target brightness information; The third general input and output terminal of the microprocessor serves as the third PWM signal output terminal of the control circuit, and is connected to the drive circuit to output the third PWM signal; the fourth general input and output terminal of the microprocessor serves as the fourth PWM signal output terminal of the control circuit and the second level signal output terminal of the control circuit, and is connected to the drive circuit to output the fourth PWM signal and the second level signal.

10. The dimming circuit for a movie light according to any one of claims 1 to 8, characterized in that: The driving circuit includes a driver, a first resistor and a second resistor; The A channel input terminal of the driver is used as the third PWM signal input terminal of the driving circuit and is connected to the control circuit to input the third PWM signal; The B channel input terminal of the driver serves as the fourth PWM signal input terminal of the driving circuit and the second level signal input terminal of the driving circuit, and is connected to the control circuit to input the fourth PWM signal and the second level signal; The A channel output end of the driver is connected to the first end of the first resistor, and the second end of the first resistor is used as the first PWM signal output end of the driving circuit and is connected to the boost circuit to output the first PWM signal; The B channel output end of the driver is connected to the first end of the second resistor, and the second end of the second resistor serves as the second PWM signal output end of the drive circuit and the first level signal output end of the drive circuit, and is connected to the switching circuit to output the second PWM signal and the first level signal.

11. The dimming circuit for a movie light according to any one of claims 1 to 8, characterized in that: Connecting with control module; The control module is connected to the main control circuit and is used to output a communication signal; the communication signal carries the target brightness information.

12. The dimming circuit for a movie light according to any one of claims 1 to 8, characterized in that: The boost circuit includes a first inductor, a first field effect transistor and a diode; The first end of the first inductor serves as an input DC power input end of the boost circuit to receive the input DC power; the second end of the first inductor, the positive electrode of the diode and the drain of the first field effect transistor are connected, and the negative electrode of the diode serves as a power supply DC power output end of the boost circuit and is connected to the light-emitting component to output the power supply DC power; the gate of the first field effect transistor serves as a first PWM signal input end of the boost circuit and is connected to the main control circuit to input the first PWM signal; the source of the first field effect transistor is connected to the power ground.

13. A controller for a film and television light, comprising the dimming circuit for a film and television light according to any one of claims 1 to 12.

14. A film and television lamp, comprising a dimming circuit and a light-emitting component for a film and television lamp as claimed in any one of claims 1 to 12.

15. A film and television lighting system, characterized in that: It comprises the controller of claim 13 and a video light, wherein the video light is separately arranged from the controller and comprises a light-emitting component.

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