Dimming circuit and electronic equipment

Abstract

The utility model discloses a dimming circuit and electronic equipment, and belongs to the technical field of LED driving. A filter circuit accesses a first PWM signal and converts the first PWM signal into an analog signal; the control circuit outputs a control signal according to the analog signal, or accesses a second PWM signal, and outputs a third PWM signal according to the second PWM signal; the driving circuit outputs power supply current according to the control signal or the third PWM signal; the light-emitting component emits light according to the power supply current; therefore, flexible switching between analog dimming and PWM dimming can be realized by adopting the dimming circuit, and the dimming circuit is suitable for multiple scenes.

Description

Technical Field

[0001] This application belongs to the field of LED driver technology, and in particular relates to a dimming circuit and electronic device. Background Technology

[0002] Currently, dimming solutions on the market are divided into two types: analog dimming and PWM dimming. Analog dimming achieves the dimming effect by changing the current of the input light-emitting diode (LED). However, the dimming depth of analog dimming cannot be high, which may cause color difference when LEDs of different colors are combined at low brightness. Pulse width modulation (PWM) dimming changes the average current of the LED by adjusting the duty cycle, thereby achieving brightness adjustment. However, PWM dimming has a low frequency, resulting in flickering during dimming and step-like changes in LED current.

[0003] Therefore, although the existing analog dimming and PWM dimming methods meet some of the LED dimming needs to a certain extent, they all have obvious drawbacks and cannot meet the diverse needs of various scenarios. As a result, the existing dimming circuits have the disadvantages of having a single dimming solution and few applicable scenarios. Utility Model Content

[0004] The purpose of this application is to provide a dimming circuit and electronic device, which aims to solve the problems of limited dimming schemes and few applicable scenarios in existing dimming circuits.

[0005] This application provides a dimming circuit connected to a light-emitting component, including:

[0006] A filtering circuit is used to receive the first PWM signal and convert the first PWM signal into an analog signal;

[0007] A control circuit, connected to the filter circuit, is used to output a control signal based on the analog signal and the sampled signal, or to input a second PWM signal, and to output a third PWM signal based on the second PWM signal and the sampled signal;

[0008] A driving circuit, connected to the control circuit and the light-emitting component, is used to output a power supply current according to the control signal or the third PWM signal;

[0009] The light-emitting component is connected to the driving circuit and is used to emit light according to the power supply current.

[0010] In one embodiment, the dimming circuit further includes:

[0011] A sampling circuit, connected to the driving circuit and the control circuit, is used to sample the power supply current and output a sampling signal;

[0012] The control circuit is specifically used to output the control signal based on the analog signal and the sampling signal, or to output the third PWM signal based on the second PWM signal and the sampling signal.

[0013] In one embodiment, the sampling circuit includes a ninth resistor;

[0014] The first end of the ninth resistor serves as the power supply current input terminal and the sampling signal output terminal of the sampling circuit, and is connected to the driving circuit and the control circuit to input the power supply current and output the sampling signal; the second end of the ninth resistor is connected to the power supply ground.

[0015] In one embodiment, the control circuit includes:

[0016] An operational amplifier module, connected to the filter circuit, the drive circuit, and the sampling circuit, is used to output a control voltage based on the analog signal and the sampled signal, or to output a fourth PWM signal based on the second PWM signal and the sampled signal.

[0017] The voltage divider module, connected to the operational amplifier module and the drive circuit, is used to divide the control voltage to output the control signal, or to divide the fourth PWM signal to output the third PWM signal.

[0018] In one embodiment, the operational amplifier module includes an operational amplifier, a fifth resistor, an eighth resistor, a tenth resistor, an eleventh resistor, and a third capacitor;

[0019] The first end of the fifth resistor serves as the analog signal input terminal and the second PWM signal input terminal of the operational amplifier module, and is connected to the filter circuit to input the analog signal and the second PWM signal; the second end of the fifth resistor is connected to the non-inverting input terminal of the operational amplifier; the first end of the tenth resistor serves as the sampling signal input terminal of the operational amplifier module, and is connected to the sampling circuit to input the sampling signal; the inverting input terminal of the operational amplifier, the first end of the third capacitor, the second end of the tenth resistor, and the first end of the eleventh resistor are connected; the second end of the third capacitor is connected to the first end of the eighth resistor; the output terminal of the operational amplifier and the second end of the eighth resistor together serve as the control voltage output terminal and the fourth PWM signal output terminal of the operational amplifier module, and are connected to the voltage divider module to output the control voltage and the fourth PWM signal; the second end of the eleventh resistor is connected to the power ground.

[0020] In one embodiment, the duty cycle of the first PWM signal is less than the duty cycle of the second PWM signal.

[0021] In one embodiment, the dimming circuit further includes:

[0022] A voltage divider circuit, connected to the filter circuit and the control circuit, is used to divide the second PWM signal to output the divided second PWM signal.

[0023] The control circuit is specifically used to output the third PWM signal based on the voltage-divided second PWM signal.

[0024] In one embodiment, the sampling circuit includes a ninth resistor;

[0025] The first end of the ninth resistor serves as the power supply current input terminal and the sampling signal output terminal of the sampling circuit, and is connected to the driving circuit and the control circuit to input the power supply current and output the sampling signal; the second end of the ninth resistor is connected to the power supply ground.

[0026] In one embodiment, the dimming circuit further includes:

[0027] A first unidirectional conduction circuit is connected to the filter circuit and the control circuit, and is used to conduct the analog signal unidirectionally so as to output the unidirectionally conducted analog signal.

[0028] The second unidirectional conduction circuit is connected to the first unidirectional conduction circuit and the control circuit, and is used to conduct the second PWM signal unidirectionally so as to output the second PWM signal after unidirectional conduction.

[0029] The control circuit is specifically used to output the control signal based on the analog signal after unidirectional conduction, or to output the third PWM signal based on the second PWM signal after unidirectional conduction.

[0030] In one embodiment, the driving circuit includes a field-effect transistor;

[0031] The gate of the field-effect transistor serves as the control signal input terminal and the fourth PWM signal input terminal of the driving circuit, and is connected to the control circuit to input the control signal and the fourth PWM signal; the drain of the field-effect transistor serves as the power supply current input terminal of the driving circuit, and is connected to the light-emitting component to input the power supply current; the source of the field-effect transistor serves as the power supply current output terminal of the driving circuit, and is connected to the sampling circuit to output the power supply current.

[0032] This application also provides an electronic device, which includes the dimming circuit described above.

[0033] The beneficial effects of this application embodiment compared with the prior art are as follows: When the first PWM signal is input, the filter circuit converts the first PWM signal into an analog signal, the control circuit outputs a control signal according to the analog signal, and the drive circuit outputs a supply current according to the control signal to realize analog dimming; when the second PWM signal is input, the control circuit outputs a third PWM signal according to the second PWM signal, and the drive circuit outputs a supply current according to the third PWM signal to realize PWM dimming; thus, the dimming circuit can realize flexible switching between analog dimming and PWM dimming, and is applicable to many scenarios. Attached Figure Description

[0034] To more clearly illustrate the technical applications in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of a dimming circuit provided in one embodiment of this application;

[0036] Figure 2 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0037] Figure 3 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0038] Figure 4 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0039] Figure 5 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0040] Figure 6 This is a partial example circuit schematic diagram of a dimming circuit provided in an embodiment of this application. Detailed Implementation

[0041] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0042] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0043] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0045] Figure 1 A schematic diagram of a dimming circuit according to an embodiment of this application is shown. For ease of explanation, only the parts relevant to this embodiment are shown, and are described in detail below:

[0046] The dimming circuit described above is connected to the light-emitting component. The dimming circuit includes a filter circuit 10, a control circuit 20, and a drive circuit 30.

[0047] The filter circuit 10 is used to receive the first PWM signal and convert the first PWM signal into an analog signal.

[0048] The control circuit 20 is connected to the filter circuit 10 and is used to output a control signal according to the analog signal, or to input a second PWM signal and output a third PWM signal according to the second PWM signal.

[0049] The driving circuit 30 is connected to the control circuit 20 and the light-emitting component, and is used to output the power supply current according to the control signal or the third PWM signal.

[0050] The light-emitting component, connected to the driving circuit 30, is used to emit light according to the supply current.

[0051] In practice, the light-emitting component can be an LED.

[0052] This dimming circuit allows for flexible switching between analog and PWM dimming, making it suitable for various scenarios. For example, it can switch to PWM dimming at low brightness levels to reduce the possibility of color difference in the light-emitting components; it can also switch to analog dimming when operating at high current to avoid flickering and step-like changes in LED current caused by low PWM dimming frequency; it can also be used when combining multiple LEDs, with different colored LEDs operating at different currents, allowing for the selection of either PWM or analog dimming for each LED to achieve the appropriate dimming effect. Furthermore, it should be understood that the above scenario descriptions are for illustrative purposes only and do not limit the application scenarios. This dimming circuit can also be used in other scenarios requiring LED dimming.

[0053] As an example rather than a limitation, such as Figure 2 As shown, the dimming circuit also includes a sampling circuit 40.

[0054] The sampling circuit 40, connected to the drive circuit 30 and the control circuit 20, is used to sample the power supply current and output a sampling signal.

[0055] The control circuit 20 is specifically used to output a control signal based on the analog signal and the sampled signal, or to output a third PWM signal based on the second PWM signal and the sampled signal.

[0056] The sampling circuit 40 samples the power supply current in real time and outputs the sampling signal to the control circuit 20, so that the control circuit 20 can perform negative feedback adjustment in real time according to the analog signal and the sampling signal, thereby enhancing the anti-interference capability of the control circuit 20.

[0057] As an example rather than a limitation, such as Figure 3 As shown, the control circuit 20 includes an operational amplifier module 21 and a voltage divider module 22.

[0058] Operational amplifier module 21 is connected to filter circuit 10, drive circuit 30 and sampling circuit 40, and is used to output control voltage according to analog signal and sampling signal, or to output fourth PWM signal according to second PWM signal and sampling signal.

[0059] The voltage divider module 22 is connected to the operational amplifier module 21 and the drive circuit 30. It is used to divide the control voltage to output a control signal, or to divide the fourth PWM signal to output a third PWM signal.

[0060] In practice, a low-pass filter can be set after the operational amplifier module 21 for filtering to improve the stability of the dimming circuit.

[0061] It should be noted that both the first PWM signal and the second PWM signal can be output by the microprocessor (not shown in the figure). However, the input / output port (I / O) driving capability of the microprocessor is insufficient. Therefore, the input signal is amplified by the operational amplifier module 21 to enhance the signal strength and meet the normal operation requirements of the subsequent circuit.

[0062] As an example and not a limitation, the duty cycle of the first PWM signal is less than the duty cycle of the second PWM signal.

[0063] Understandably, when the control signal is input, the field-effect transistor in the drive circuit 30 operates in the variable resistance region, so the field-effect transistor can adjust the supply current according to the voltage of the input control signal to achieve analog dimming; as the voltage of the control signal increases, the field-effect transistor operates in the saturation region, so the field-effect transistor needs to select PWM dimming. Therefore, by flexibly applying the characteristics of the field-effect transistor, the switching between the two dimming modes is realized, which improves the dimming accuracy of the dimming circuit. The circuit is simple, flexible and easy to use.

[0064] As an example rather than a limitation, such as Figure 4 As shown, the dimming circuit also includes a voltage divider circuit 50.

[0065] The voltage divider circuit 50 is connected to the filter circuit 10 and the control circuit 20. It is used to divide the second PWM signal to output the divided second PWM signal.

[0066] The control circuit 20 is specifically used to output a third PWM signal based on the voltage-divided second PWM signal.

[0067] The voltage divider circuit 50 can reduce the amplitude of the second PWM signal to a safe range, thereby reducing the possibility of damage to components in subsequent circuits and improving the reliability and stability of the entire system.

[0068] As an example rather than a limitation, such as Figure 5 As shown, the dimming circuit also includes a first unidirectional conduction circuit 60 and a second unidirectional conduction circuit 70.

[0069] The first unidirectional conduction circuit 60 is connected to the filter circuit 10 and the control circuit 20, and is used to conduct analog signals unidirectionally so as to output the unidirectionally conducted analog signal.

[0070] The second unidirectional conduction circuit 70 is connected to the first unidirectional conduction circuit 60 and the control circuit 20, and is used to conduct the second PWM signal in one direction so as to output the second PWM signal after unidirectional conduction.

[0071] The control circuit 20 is specifically used to output a control signal based on the analog signal after unidirectional conduction, or to output a third PWM signal based on the second PWM signal after unidirectional conduction.

[0072] The first unidirectional conduction circuit 60 and the second unidirectional conduction circuit 70 reduce the possibility of voltage backflow and improve the safety and reliability of the dimming circuit.

[0073] Figure 6 The illustration shows a partial example circuit structure of a dimming circuit provided in an embodiment of this application. For ease of explanation, only the parts relevant to the embodiment of this application are shown, and are described in detail below:

[0074] The voltage divider circuit 50 includes a third resistor R3 and a fourth resistor R4.

[0075] The first end of the third resistor R3 serves as the second PWM signal input terminal of the voltage divider circuit 50 to input the second PWM signal; the second end of the third resistor R3 and the first end of the fourth resistor R4 together serve as the second PWM signal output terminal of the voltage divider circuit 50, which is connected to the filter circuit 10 and the control circuit 20 to output the second PWM signal after voltage division.

[0076] This circuit consists only of resistors, making it simple to design and low in cost.

[0077] The operational amplifier module 21 includes an operational amplifier M1, a fifth resistor R5, an eighth resistor R8, a tenth resistor R10, an eleventh resistor R11, and a third capacitor C3.

[0078] The first end of the fifth resistor R5 serves as the analog signal input terminal and the second PWM signal input terminal of the operational amplifier module 21, and is connected to the filter circuit 10 to input the analog signal and the second PWM signal; the second end of the fifth resistor R5 is connected to the non-inverting input terminal of the operational amplifier M1; the first end of the tenth resistor R10 serves as the sampling signal input terminal of the operational amplifier module 21, and is connected to the sampling circuit 40 and the drive circuit 30 to input the sampling signal; the inverting input terminal of the operational amplifier M1, the first end of the third capacitor C3, the second end of the tenth resistor R10, and the first end of the eleventh resistor R11 are connected; the second end of the third capacitor C3 is connected to the first end of the eighth resistor R8; the output terminal of the operational amplifier M1 and the second end of the eighth resistor R8 together serve as the control voltage output terminal and the fourth PWM signal output terminal of the operational amplifier module 21, and are connected to the voltage divider module 22 to output the control voltage and the fourth PWM signal; the second end of the eleventh resistor R11 is connected to the power supply ground.

[0079] It should be noted that because the sampling circuit 40 needs to sample the supply current and output a sampled signal to the operational amplifier M1, the feedback loop of the operational amplifier M1 becomes too long, resulting in a slow response rate and thus causing self-oscillation at the output of the operational amplifier M1. To address this, a third capacitor C3 and an eighth resistor R8 are used for high-frequency negative feedback. As the frequency increases, the impedance of the capacitor decreases, thus enhancing the negative feedback at high frequencies. This reduces the current ripple of the output signal, minimizes interference with the drive circuit 30, suppresses the self-oscillation of the operational amplifier M1, and ensures its stable operation. Understandably, in practical applications, appropriate capacitor values ​​can be selected based on actual needs.

[0080] The filter circuit 10 includes a first resistor R1, a second resistor R2, a first capacitor C1, and a second capacitor C2.

[0081] The first end of the first resistor R1 serves as the first PWM signal input terminal of the filter circuit 10 to receive the first PWM signal; the second end of the first resistor R1, the first end of the first capacitor C1, and the first end of the second resistor R2 are connected together, and the second end of the second resistor R2 and the first end of the second capacitor C2 together serve as the analog signal output terminal of the filter circuit 10, connected to the control circuit 20 to output an analog signal; the second end of the first capacitor C1 and the second end of the second capacitor C2 are connected to the power supply ground.

[0082] The filter circuit 10 only includes resistors and capacitors, making the circuit simple and reducing the difficulty and workload of circuit design.

[0083] The driving circuit 30 includes a field-effect transistor Q1.

[0084] The gate of the field-effect transistor Q1 serves as the control signal input terminal and the fourth PWM signal input terminal of the driving circuit 30, and is connected to the control circuit 20 to input the control signal and the fourth PWM signal; the drain of the field-effect transistor Q1 serves as the power supply current input terminal of the driving circuit 30, and is connected to the light-emitting component to input the power supply current; the source of the field-effect transistor Q1 serves as the power supply current output terminal of the driving circuit 30, and is connected to the sampling circuit 40 to output the power supply current.

[0085] It is understandable that when the control voltage is applied, the field-effect transistor Q1 operates in the variable resistance region, thus allowing Q1 to adjust the supply current according to the magnitude of the applied control voltage, achieving analog dimming. When the fourth PWM signal is applied, the operating state of Q1 switches between the cutoff region and the variable resistance region, or between the cutoff region and the saturation region, thereby achieving PWM dimming. Therefore, by flexibly applying the characteristics of the field-effect transistor Q1, the switching between the two dimming modes is achieved. The circuit is simple, flexible, and easy to use.

[0086] The sampling circuit 40 includes a ninth resistor R9.

[0087] The first end of the ninth resistor R9 serves as the power supply current input terminal and the sampling signal output terminal of the sampling circuit 40, and is connected to the drive circuit 30 and the control circuit 20 to input the power supply current and output the sampling signal; the second end of the ninth resistor R9 is connected to the power supply ground.

[0088] This circuit is simple and reliable.

[0089] The first unidirectional conduction circuit 60 includes a first diode D1.

[0090] The positive terminal of the first diode D1 serves as the analog signal input terminal of the first unidirectional conduction circuit 60 and is connected to the filter circuit 10 to input an analog signal; the negative terminal of the first diode D1 serves as the analog signal output terminal of the first unidirectional conduction circuit 60 after unidirectional conduction and is connected to the control circuit 20 to output the analog signal after unidirectional conduction.

[0091] The second unidirectional conduction circuit 70 includes a second diode D2.

[0092] The positive terminal of the second diode D2 serves as the second PWM signal input terminal of the second unidirectional conduction circuit 70 and is connected to the filter circuit 10 to input the second PWM signal; the negative terminal of the second diode D2 serves as the second PWM signal output terminal after unidirectional conduction of the second unidirectional conduction circuit 70 and is connected to the control circuit 20 to output the second PWM signal after unidirectional conduction.

[0093] Voltage divider module 22 includes a sixth resistor R6 and a seventh resistor R7.

[0094] The first end of the sixth resistor R6 serves as the control voltage input terminal and the fourth PWM signal input terminal of the voltage divider module 22, and is connected to the operational amplifier module 21 to input the control voltage or the fourth PWM signal; the second end of the sixth resistor R6 and the first end of the seventh resistor R7 together serve as the control signal output terminal and the third PWM signal output terminal of the voltage divider module 22, and are connected to the drive circuit 30 to output the control signal or the third PWM signal; the second end of the seventh resistor R7 is connected to the power supply ground.

[0095] The following is based on the working principle. Figure 6 Further explanation is provided below:

[0096] When the first terminal of the first resistor R1 is connected to the first PWM signal, the first resistor R1, the second resistor R2, the first capacitor C1, and the second capacitor C2 filter the first PWM signal. An analog signal is then output from the second terminal of the second resistor R2 and the first terminal of the second capacitor C2, passing through the fifth resistor R5 to the non-inverting input of operational amplifier M1. At this time, the inverting input of operational amplifier M1 is grounded through the eleventh resistor R11. Operational amplifier M1 outputs a control voltage to the first terminal of the sixth resistor R6. The sixth resistor R6 and the seventh resistor R7 divide the control voltage and output a control signal to the gate of the field-effect transistor Q1. The field-effect transistor Q1 is turned on, transmitting the supply current. The first terminal of the ninth resistor R9 is connected to the supply current. The ninth resistor R9 samples the supply current and outputs a signal from its first terminal. The sampling signal is sent to the first terminal of the tenth resistor R10. After being divided by the tenth and eleventh resistors, the sampling signal is transmitted to the inverting input terminal of the operational amplifier M1, forming a negative feedback loop of the operational amplifier M1. The operational amplifier M1 adjusts the value of the control voltage according to the difference between the voltage of the analog signal and the voltage of the sampling signal (this process is short). When the voltage of the analog signal is approximately equal to the voltage of the sampling signal, the value of the control voltage output by the operational amplifier M1 is basically stable (due to interference or differences in components in the actual circuit, the voltage value output by the operational amplifier M1 will fluctuate around a constant value). At this time, the field-effect transistor Q1 transmits the corresponding supply current according to the control voltage. Since the field-effect transistor Q1 is working in the variable resistance region at this time, different control voltages correspond to different supply current values, thereby realizing analog dimming.

[0097] When the first terminal of the third resistor R3 is connected to the second PWM signal, the third resistor R3 and the fourth resistor R4 divide the second PWM signal and output the divided second PWM signal, which is then input to the non-inverting input terminal of the operational amplifier M1 via the fifth resistor R5. Based on the above analysis of the operating state of the operational amplifier M1, when the second PWM signal is high, the operational amplifier M1 outputs a high level according to the sampling signal and the second PWM signal; when the second PWM signal is low, the operational amplifier M1 outputs a low level. Therefore, the operational amplifier M1 outputs a fourth PWM signal to the first terminal of the sixth resistor R6. The sixth resistor R6 and the seventh resistor R7 divide the fourth PWM signal voltage and output a third PWM signal from the second terminal of the sixth resistor R6 and the first terminal of the seventh resistor R7 to the gate of the field-effect transistor Q1. The field-effect transistor Q1 conducts when the third PWM signal is high. The ninth resistor R9 samples the supply current and outputs a sampling signal to achieve negative feedback of the operational amplifier M1. The field-effect transistor Q1 is turned off when the third PWM signal is low. Therefore, different duty cycles correspond to different average supply current values, thus achieving PWM dimming.

[0098] This application also provides an electronic device that includes the dimming circuit described above.

[0099] It should be understood that the sequence number of each step in the above embodiments does not imply 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 this application.

[0100] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A dimming circuit, characterized in that, Connected to the light-emitting component, including: A filtering circuit is used to receive the first PWM signal and convert the first PWM signal into an analog signal; A control circuit, connected to the filter circuit, is used to output a control signal according to the analog signal, or to input a second PWM signal and output a third PWM signal according to the second PWM signal; A driving circuit, connected to the control circuit and the light-emitting component, is used to output a power supply current according to the control signal or the third PWM signal; The light-emitting component is connected to the driving circuit and is used to emit light according to the power supply current.

2. The dimming circuit as described in claim 1, characterized in that, Also includes: A sampling circuit, connected to the driving circuit and the control circuit, is used to sample the power supply current and output a sampling signal; The control circuit is specifically used to output the control signal based on the analog signal and the sampling signal, or to output the third PWM signal based on the second PWM signal and the sampling signal.

3. The dimming circuit as described in claim 2, characterized in that, The sampling circuit includes a ninth resistor; The first end of the ninth resistor serves as the power supply current input terminal and the sampling signal output terminal of the sampling circuit, and is connected to the driving circuit and the control circuit to input the power supply current and output the sampling signal. The second end of the ninth resistor is connected to the power supply ground.

4. The dimming circuit as described in claim 2, characterized in that, The control circuit includes: An operational amplifier module, connected to the filter circuit, the drive circuit, and the sampling circuit, is used to output a control voltage based on the analog signal and the sampled signal, or to output a fourth PWM signal based on the second PWM signal and the sampled signal. The voltage divider module, connected to the operational amplifier module and the drive circuit, is used to divide the control voltage to output the control signal, or to divide the fourth PWM signal to output the third PWM signal.

5. The dimming circuit as described in claim 4, characterized in that, The operational amplifier module includes an operational amplifier, a fifth resistor, an eighth resistor, a tenth resistor, an eleventh resistor, and a third capacitor; The first end of the fifth resistor serves as the analog signal input terminal and the second PWM signal input terminal of the operational amplifier module, and is connected to the filter circuit to input the analog signal and the second PWM signal; the second end of the fifth resistor is connected to the non-inverting input terminal of the operational amplifier; the first end of the tenth resistor serves as the sampling signal input terminal of the operational amplifier module, and is connected to the sampling circuit and the drive circuit to input the sampling signal; the inverting input terminal of the operational amplifier, the first end of the third capacitor, the second end of the tenth resistor, and the first end of the eleventh resistor are connected; the second end of the third capacitor is connected to the first end of the eighth resistor; the output terminal of the operational amplifier and the second end of the eighth resistor together serve as the control voltage output terminal and the fourth PWM signal output terminal of the operational amplifier module, and are connected to the voltage divider module to output the control voltage and the fourth PWM signal; the second end of the eleventh resistor is connected to the power ground.

6. The dimming circuit as described in claim 1, characterized in that, The duty cycle of the first PWM signal is less than the duty cycle of the second PWM signal.

7. The dimming circuit as described in claim 1, characterized in that, Also includes: A voltage divider circuit, connected to the filter circuit and the control circuit, is used to divide the second PWM signal to output the divided second PWM signal. The control circuit is specifically used to output the third PWM signal based on the voltage-divided second PWM signal.

8. The dimming circuit as described in claim 1, characterized in that, Also includes: A first unidirectional conduction circuit is connected to the filter circuit and the control circuit, and is used to conduct the analog signal unidirectionally so as to output the unidirectionally conducted analog signal. The second unidirectional conduction circuit is connected to the first unidirectional conduction circuit and the control circuit, and is used to conduct the second PWM signal unidirectionally so as to output the second PWM signal after unidirectional conduction. The control circuit is specifically used to output the control signal based on the analog signal after unidirectional conduction, or to output the third PWM signal based on the second PWM signal after unidirectional conduction.

9. The dimming circuit as described in claim 1, characterized in that, The driving circuit includes a field-effect transistor; The gate of the field-effect transistor serves as the control signal input terminal and the fourth PWM signal input terminal of the driving circuit, and is connected to the control circuit to input the control signal and the fourth PWM signal. The drain of the field-effect transistor serves as the power supply current input terminal of the driving circuit and is connected to the light-emitting component to input the power supply current. The source of the field-effect transistor serves as the power supply current output terminal of the driving circuit and is connected to the sampling circuit to output the power supply current.

10. An electronic device, characterized in that, Includes the dimming circuit as described in any one of claims 1 to 9.

Images