Dimming circuit and electronic equipment

Abstract

A dimming circuit and an electronic device belong to the technical field of electronic circuits, and boost an input direct current through a boost circuit according to a first PWM control signal to output a first direct current; the current adjusting circuit shunts the first direct current according to the second PWM control signal so as to output an output direct current; the light-emitting component emits light according to the output direct current; wherein after the duty ratio of the first PWM control signal is increased to a first preset value, the duty ratio of the second PWM control signal is gradually decreased to a fourth preset value from a third preset value while the duty ratio of the first PWM control signal is gradually increased to a second preset value from the first preset value; therefore, the minimum response current output by the dimming circuit is reduced, the build-up current and the minimum brightness of the light-emitting component are reduced, the dimming range is widened, and the adjustment precision is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic circuits, and particularly relates to a dimming circuit and an electronic device. BACKGROUND

[0002] In the traditional dimming system on the market, a switching constant current circuit and a linear constant current circuit are generally used to dim a light emitting component. The switching constant current circuit mainly includes two topologies, i.e., a boost type and a buck type. The traditional switching constant current circuit has high efficiency and can adapt to a large input voltage variation range. The minimum response current (i.e., the minimum current required by the light emitting component for light emission) of the output is large, the current ripple is large, and the control precision is low, which leads to that the dimming of the switching constant current circuit is not smooth, the start-up current of the light emitting component is large, and the minimum brightness is high, so that the low brightness adjustment and high precision adjustment of the light emitting component cannot be realized. The traditional linear constant current circuit has high adjustment precision, but has certain limitation on the variation range of the input voltage. When the input voltage varies greatly, the stability of the constant current output is affected, and smooth adjustment from low brightness to high brightness cannot be realized.

[0003] Therefore, there is an urgent need to provide a dimming circuit with small minimum response current, high adjustment precision and wide dimming range. CONTENT OF THE INVENTION

[0004] The application aims to provide a dimming circuit and an electronic device, and aims to solve the problems of large minimum response current, low adjustment precision and low stability of the existing dimming circuit.

[0005] The application provides a dimming circuit connected with a light emitting component, comprising:

[0006] a boost circuit connected with the light emitting component, configured to input an input direct current and a first PWM control signal, and to boost the input direct current according to the first PWM control signal to output a first direct current;

[0007] a current adjustment circuit connected with the light emitting component and the boost circuit, configured to shunt the first direct current according to a second PWM control signal to output an output direct current;

[0008] the light emitting component is configured to emit light according to the output direct current;

[0009] The duty cycle of the first PWM control signal gradually increases to a first preset value, and when the duty cycle of the first PWM control signal gradually increases from the first preset value to a second preset value, the duty cycle of the second PWM control signal gradually decreases from a third preset value to a fourth preset value.

[0010] In one of the embodiments, the current regulating circuit comprises:

[0011] a first switch module, configured to output a first PWM signal according to the second PWM control signal;

[0012] a second switch module, connected with the first switch module and the voltage boosting circuit, configured to shunt the first direct current according to the first PWM signal to output the output direct current.

[0013] In one of the embodiments, the current regulating circuit is specifically configured to shunt the output direct current according to the second PWM control signal to output the output direct current and a second direct current.

[0014] The dimming circuit further comprises:

[0015] a current sampling circuit, connected with the light emitting component, the voltage boosting circuit and the current regulating circuit, configured to sample the current of the output direct current and the current of the second direct current to output a current sampling signal.

[0016] The voltage boosting circuit is specifically configured to boost the input direct current according to the first PWM control signal and the current sampling signal to output the first direct current.

[0017] In one of the embodiments, the current sampling circuit comprises an eighth resistor.

[0018] A first end of the eighth resistor is connected with the light emitting component, the voltage boosting circuit and the current regulating circuit as an output direct current input end of the current sampling circuit, a second direct current input end of the current sampling circuit and a current sampling signal output end of the current sampling circuit to input the output direct current and the second direct current and output the current sampling signal; a second end of the eighth resistor is connected to a power supply ground.

[0019] In one of the embodiments, the dimming circuit further comprises:

[0020] a slope compensation circuit, connected with the voltage boosting circuit, configured to output a slope compensation signal.

[0021] The voltage boosting circuit is specifically configured to boost the input direct current according to the first PWM control signal and the slope compensation signal to output the first direct current.

[0022] In one of the embodiments, the dimming circuit further comprises:

[0023] The voltage sampling circuit is connected with the light-emitting component, the voltage boosting circuit and the current regulating circuit, and is configured to sample a voltage of the first direct current to output a sampling voltage.

[0024] The voltage boosting circuit is specifically configured to boost the input direct current according to the first PWM control signal and the sampling voltage to output the first direct current.

[0025] In one of the embodiments, the dimming circuit further comprises:

[0026] The first filter circuit is connected with the current regulating circuit, and is configured to filter the second PMW control signal to output a filtered second PMW control signal.

[0027] The current regulating circuit is specifically configured to output the output direct current according to the filtered second PMW control signal.

[0028] In one of the embodiments, the dimming circuit further comprises:

[0029] The interference suppression circuit is connected with the voltage boosting circuit, and is configured to suppress high-frequency interference of the input direct current to output the input direct current after high-frequency interference suppression.

[0030] The second filter circuit is connected with the interference suppression circuit and the voltage boosting circuit, and is configured to filter the input direct current after high-frequency interference suppression to output the input direct current after filtering.

[0031] The voltage boosting circuit is specifically configured to boost the input direct current after filtering according to the first PWM control signal to output the first direct current.

[0032] In one of the embodiments, the voltage boosting circuit comprises a voltage boosting constant current driver, a first field effect transistor, an inductor, a first diode, a second diode, a first resistor, a second resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a sixteenth resistor, a seventeenth resistor, a first capacitor, a second capacitor, a third capacitor, a sixth capacitor, a seventh capacitor, a tenth capacitor and an eleventh capacitor.

[0033] The first terminal of the first resistor serves as the first PWM control signal input terminal of the boost circuit to input the first PWM control signal; the second terminal of the first resistor, the pulse width modulation input terminal (PWM) of the boost constant current driver, the first terminal of the second resistor, and the first terminal of the second capacitor are connected; the current feedback input terminal of the boost constant current driver serves as the current sampling signal input terminal of the boost circuit and is connected to the current adjustment circuit, the light-emitting component, and the voltage sampling circuit to receive the current sampling signal; the voltage feedback input terminal of the boost constant current driver serves as the sampling voltage input of the boost circuit. The first terminal of the boost constant current driver is connected to the voltage sampling circuit to receive the sampling voltage; the compensation terminal of the boost constant current driver serves as the ramp compensation signal input terminal of the boost circuit and is connected to the ramp compensation circuit to input the ramp compensation signal; the first terminal of the fourth resistor and the first terminal of the inductor together serve as the input DC current input terminal of the boost circuit to input the input DC current; the input voltage terminal of the boost constant current driver, the second terminal of the fourth resistor, and the first terminal of the sixth capacitor are connected; the driving terminal of the boost constant current driver, the cathode of the first diode, and the first terminal of the fifth resistor are connected; the anode of the first diode... The first terminal of the sixth resistor is connected to the second terminal of the fifth resistor, the second terminal of the sixth resistor and the gate of the first field-effect transistor are connected to the second terminal of the inductor, the positive terminal of the second diode, the first terminal of the tenth capacitor, the first terminal of the eleventh capacitor and the drain of the first field-effect transistor are connected to the second terminal of the boost constant current driver, the source of the first field-effect transistor and the first terminal of the seventh resistor are connected to the second terminal of the boost constant current driver, the negative terminal of the second diode and the first terminal of the seventh capacitor together serve as the first DC output terminal of the boost circuit, which is connected to the light-emitting component, the current adjustment circuit and the light-emitting component to output the first DC current; the second terminal of the sixteenth resistor and the second terminal of the tenth capacitor are connected to the second terminal of the eleventh capacitor and the first terminal of the seventeenth resistor are connected to the first power supply; the power supply terminal of the boost constant current driver and the first terminal of the third capacitor are connected to the first power supply; the second terminal of the second resistor, the ground terminal of the boost constant current driver, the second terminal of the second capacitor, the second terminal of the third capacitor, the second terminal of the sixth capacitor, the second terminal of the seventh resistor, the second terminal of the seventeenth resistor and the second terminal of the seventh capacitor are connected to the power supply ground.

[0034] This application also provides an electronic device, which includes the dimming circuit described above.

[0035] The beneficial effects of this application embodiment compared with the prior art are as follows: the boost circuit boosts the input DC power according to the first PWM control signal to output the first DC power, and the current regulation circuit shunts the first DC power according to the second PWM control signal to output the output DC power. Thus, without changing the output voltage of the dimming circuit, the minimum response current of the dimming circuit is reduced, thereby reducing the start-up current and minimum brightness of the light-emitting component and widening the dimming range of the dimming circuit.

[0036] After the first DC current output by the boost circuit becomes constant (i.e., after the duty cycle of the first PWM control signal rises to the first preset value), the boost circuit increases the brightness of the light-emitting component according to the gradual increase of the duty cycle of the first PWM control signal, thus achieving coarse adjustment of the brightness of the light-emitting component. At the same time, the current regulation circuit reduces the shunting of the first DC current according to the gradual decrease of the second PWM control signal, thus achieving fine adjustment of the brightness of the light-emitting component. In this way, by setting the duty cycle of the first PWM control signal to be inversely proportional to the duty cycle of the second PWM control signal, the adjustment accuracy of the output DC current is improved, ensuring the smoothness of the dimming process and achieving a more delicate and uniform brightness adjustment effect, realizing a smooth transition of the light-emitting component from extremely dark to extremely bright. Attached Figure Description

[0037] 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.

[0038] Figure 1 This is a schematic diagram of a dimming circuit provided in one embodiment of this application;

[0039] Figure 2 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0040] Figure 3 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0041] Figure 4 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0042] Figure 5 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0043] Figure 6 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0044] Figure 7 This is a schematic diagram of another structure of the dimming circuit provided in one embodiment of this application;

[0045] Figure 8 This is a partial example circuit schematic diagram of a dimming circuit provided in an embodiment of this application. Detailed Implementation

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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:

[0051] The dimming circuit described above is connected to the light-emitting component. The dimming circuit includes a boost circuit 10 and a current regulation circuit 20.

[0052] The boost circuit 10 is connected to the light-emitting component and is used to receive the input DC power and the first PWM control signal. It boosts the input DC power according to the first PWM control signal to output the first DC power.

[0053] The current regulation circuit 20, connected to the light-emitting component and the boost circuit 10, is used to shunt the first DC current according to the second PWM control signal to output DC current.

[0054] The light-emitting component is used to emit light according to the output DC power.

[0055] Among them, after the duty cycle of the first PWM control signal rises to the first preset value, while the duty cycle of the first PWM control signal gradually rises from the first preset value to the second preset value, the duty cycle of the second PWM control signal gradually decreases from the third preset value to the fourth preset value.

[0056] It should be noted that when the duty cycle of the first PWM control signal is greater than the second preset value, the duty cycle of the second PWM control signal can be the fourth preset value. In this case, the brightness of the light-emitting component can be directly adjusted through the boost circuit 10, without the need for fine-tuning the brightness of the light-emitting component through the current regulation circuit 20. This reduces the possibility of unstable output DC current when the voltage of the first DC power supply changes significantly, and improves the stability and reliability of the dimming circuit.

[0057] In traditional dimming systems, when combining multiple light sources, the high minimum brightness and low adjustment precision of each light source affect the overall light efficiency and color reproduction. By setting up a boost circuit 10 and a current adjustment circuit 20, the minimum brightness of each light source can be reduced, and the adjustment precision of each light source can be improved. This achieves a smooth transition from extremely dark to extremely bright light sources, thereby improving the consistency and accuracy of color when combining multiple light sources, and enhancing the overall light efficiency and color reproduction.

[0058] The first, second, third, and fourth preset values ​​can all be set according to actual needs, and this application does not impose any restrictions on them.

[0059] As an example rather than a limitation, such as Figure 2 As shown, the current regulation circuit 20 includes a first switch module 21 and a second switch module 22.

[0060] The first switching module 21 is used to output a first PWM signal according to the second PWM control signal.

[0061] The second switch module 22 is connected to the first switch module 21 and the boost circuit 10, and is used to shunt the first DC power according to the first PWM signal to output DC power.

[0062] The adjustment range of the current regulation circuit 20 is improved by setting a two-stage switching module.

[0063] As an example rather than a limitation, such as Figure 3As shown, the current regulation circuit 20 is specifically used to shunt the output DC power according to the second PWM control signal to output the output DC power and the second DC power.

[0064] The dimming circuit also includes a current sampling circuit 30.

[0065] The current sampling circuit 30 is connected to the light-emitting component, the boost circuit 10 and the current regulation circuit 20, and is used to sample the current of the output DC current and the current of the second DC current to output a current sampling signal.

[0066] The boost circuit 10 is specifically used to boost the input DC power according to the first PWM control signal and the current sampling signal, so as to output the first DC power.

[0067] The current sampling circuit 30 enables real-time monitoring and feedback of the output DC and second DC currents, improving the stability and reliability of the dimming circuit.

[0068] As an example rather than a limitation, such as Figure 4 As shown, the dimming circuit also includes a slope compensation circuit 40.

[0069] The ramp compensation circuit 40 is connected to the boost circuit 10 and is used to output the ramp compensation signal.

[0070] The boost circuit 10 specifically boosts the input DC power according to the first PWM control signal and the slope compensation signal to output the first DC power.

[0071] The slope compensation circuit 40 reduces the fluctuations in the first DC current and voltage, improves the stability of the first DC current, and thus improves the stability of the dimming circuit.

[0072] As an example rather than a limitation, such as Figure 5 As shown, the dimming circuit also includes a voltage sampling circuit 50.

[0073] The voltage sampling circuit 50 is connected to the light-emitting component, the boost circuit 10 and the current regulation circuit 20, and is used to sample the voltage of the first DC current to output the sampled voltage.

[0074] The boost circuit 10 is specifically used to boost the input DC power according to the first PWM control signal and the sampled voltage to output the first DC power.

[0075] The voltage sampling circuit 50 enables real-time monitoring and feedback of the voltage of the first DC current, thereby improving the stability and reliability of the dimming circuit.

[0076] As an example rather than a limitation, such as Figure 6 As shown, the dimming circuit also includes a first filter circuit 60.

[0077] The first filter circuit 60 is connected to the current regulation circuit 20 and is used to filter the second PWM control signal to output the filtered second PWM control signal.

[0078] The current regulation circuit 20 is specifically used to output DC power according to the filtered second PMW control signal.

[0079] The stability of the dimming circuit is improved by the first filter circuit 60.

[0080] As an example rather than a limitation, such as Figure 7 As shown, the dimming circuit also includes an interference suppression circuit 70 and a second filter circuit 80.

[0081] Interference suppression circuit 70, connected to boost circuit 10, is used to suppress high-frequency interference in the input DC power so as to output the input DC power after high-frequency interference suppression.

[0082] The second filter circuit 80 is connected to the interference suppression circuit 70 and the boost circuit 10. It is used to filter the input DC power after high-frequency interference suppression so as to output the filtered input DC power.

[0083] The boost circuit 10 is specifically used to boost the filtered input DC power according to the first PWM control signal to output the first DC power.

[0084] The stability of the dimming circuit is further improved by the interference suppression circuit 70 and the second filter circuit 80.

[0085] As an example and not a limitation, the dimming circuit also includes an interference suppression module.

[0086] The interference suppression module is connected to the boost circuit 10, the current dimming circuit, the voltage sampling circuit 50, and the light-emitting component to suppress high-frequency interference in the output DC power.

[0087] Figure 8 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:

[0088] The current sampling circuit 30 includes an eighth resistor R8.

[0089] The first end of the eighth resistor R8 serves as the output DC input terminal, the second DC input terminal, and the current sampling signal output terminal of the current sampling circuit 30. It is connected to the light-emitting component, the boost circuit 10, and the current regulation circuit 20 to input and output DC and second DC, and output the current sampling signal. The second end of the eighth resistor R8 is connected to the power supply ground.

[0090] The circuit's electronic components consist only of resistors, making it inexpensive.

[0091] The boost circuit 10 includes a boost constant current driver U1, a first field-effect transistor Q1, an inductor L1, a first diode D1, a second diode D2, a first resistor R1, a second resistor R2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a sixteenth resistor R16, a seventeenth resistor R17, a first capacitor C1, a second capacitor C2, a third capacitor C3, a sixth capacitor C6, a seventh capacitor C7, a tenth capacitor C10, and an eleventh capacitor C11.

[0092] The first end of the first resistor R1 serves as the first PWM control signal input terminal of the boost circuit 10, to input the first PWM control signal; the second end of the first resistor R1, the pulse width modulation input terminal PWM of the boost constant current driver U1, the first end of the second resistor R2, and the first end of the second capacitor C2 are connected; the current feedback input terminal IF of the boost constant current driver U1 serves as the current sampling signal input terminal of the boost circuit 10, and is connected to the current adjustment circuit 20, the light-emitting component, and the voltage sampling circuit 50 to receive the current sampling signal; the voltage feedback input terminal VF of the boost constant current driver U1 serves as the sampling voltage input terminal of the boost circuit 10, and is connected to... Voltage sampling circuit 50 is connected to receive the sampling voltage; the compensation terminal C of boost constant current driver U1 serves as the ramp compensation signal input terminal of boost circuit 10, and is connected to ramp compensation circuit 40 to input the ramp compensation signal; the first terminal of the fourth resistor R4 and the first terminal of inductor L1 together serve as the input DC power input terminal of boost circuit 10 to input DC power; the input voltage terminal VIN of boost constant current driver U1, the second terminal of the fourth resistor R4 and the first terminal of the sixth capacitor C6 are connected, the driving terminal Gate of boost constant current driver U1, the cathode of the first diode D1 and the first terminal of the fifth resistor R5 are connected, and the positive terminal of the first diode D1... The first terminal of the fifth resistor R5 and the second terminal of the sixth resistor R6 are connected to the gate of the first field-effect transistor Q1. The second terminal of the inductor L1, the anode of the second diode D2, the first terminal of the tenth capacitor C10, the first terminal of the eleventh capacitor C11, and the drain of the first field-effect transistor Q1 are connected. The current detection terminal CS of the boost constant current driver U1, the source of the first field-effect transistor Q1, and the first terminal of the seventh resistor R7 are connected. The first terminal of the sixteenth resistor R16, the cathode of the second diode D2, and the first terminal of the seventh capacitor C7 together serve as the first DC output terminal of the boost circuit 10, which is connected to the light-emitting component and the current... The regulating circuit 20 is connected to the light-emitting component to output the first DC current; the second end of the sixteenth resistor R16 is connected to the second end of the tenth capacitor C10, the second end of the eleventh capacitor C11 is connected to the first end of the seventeenth resistor R17, the power supply terminal VDD of the boost constant current driver U1 and the first end of the third capacitor C3 are connected to the first power supply, and the second end of the second resistor R2, the ground terminal GND of the boost constant current driver U1, the second end of the second capacitor C2, the second end of the third capacitor C3, the second end of the sixth capacitor C6, the second end of the seventh resistor R7, the second end of the seventeenth resistor R17 and the second end of the seventh capacitor C7 are connected to the power supply ground.

[0093] Among them, the seventh capacitor C7 is an energy storage capacitor, and the capacitance and number of energy storage capacitors can be set according to actual needs; the second diode D2 is used to prevent the voltage in the seventh capacitor C7 from flowing back to the front-end circuit.

[0094] The sixteenth resistor R16, the seventeenth resistor R17, the tenth capacitor C10, and the eleventh capacitor C11 are used to absorb the peak voltage of the first DC current to improve the stability of the dimming circuit.

[0095] This circuit achieves both boost and constant current through the boost constant current driver U1, resulting in high circuit integration and high reliability.

[0096] The first switching module 21 includes a transistor A1.

[0097] The base of transistor A1 serves as the input terminal of the filtered second PWM control signal of the first switching module 21 and is connected to the first filtering circuit 60 to input the filtered second PWM control signal; the collector of transistor A1 serves as the output terminal of the first PWM signal of the first switching module 21 and is connected to the second switching module 22 to output the first PWM signal; the emitter of transistor A1 is connected to the power supply ground.

[0098] The transistor A1 can also be replaced with other switching transistors, such as a field-effect transistor, and this application does not limit this.

[0099] The second switching module 22 includes a second field-effect transistor Q2, an eleventh resistor R11, a twelfth resistor R12, and a thirteenth resistor R13.

[0100] The gate of the second field-effect transistor Q2, the first end of the twelfth resistor R12, and the first end of the thirteenth resistor R13 together serve as the first PWM signal input terminal of the second switching module 22, and are connected to the first switching module 21 to input the first PWM signal; the first end of the eleventh resistor R11 serves as the first DC input terminal and the second DC output terminal of the second switching module 22, and is connected to the boost circuit 10 to input the first DC power and output the DC power; the second end of the eleventh resistor R11, the second end of the twelfth resistor R12, and the drain of the second field-effect transistor Q2 are connected, and the source of the second field-effect transistor Q2 serves as the second DC output terminal of the second switching module 22, and is connected to the light-emitting component, the first switching module 21, and the boost circuit 10 to output the second DC power; the second end of the thirteenth resistor R13 is connected to the power ground.

[0101] By changing the duty cycle of the second PWM control signal, the conduction level of transistor A1 can be adjusted to regulate the gate voltage of the second field-effect transistor Q2 (i.e., the voltage between the collector of transistor A1 and the transmitter), thereby adjusting the conduction level of the second field-effect transistor Q2, and ultimately changing the shunting magnitude of the output DC current according to the duty cycle of the second PWM control signal.

[0102] The slope compensation circuit 40 includes a third resistor R3, a fourth capacitor C4, and a fifth capacitor C5.

[0103] The first end of the third resistor R3 and the first end of the fifth capacitor C5 together serve as the slope compensation signal output terminal of the slope compensation circuit 40, which is connected to the boost circuit 10 to output the slope compensation signal; the second end of the third resistor R3 and the first end of the fourth capacitor C4 are connected, and the second end of the fourth capacitor C4 and the second end of the fifth capacitor C5 are connected to the power supply ground.

[0104] The voltage sampling circuit 50 includes a ninth resistor R9 and a tenth resistor R10.

[0105] The first end of the ninth resistor R9 serves as the first DC input terminal of the voltage sampling circuit 50, and is connected to the light-emitting component, the boost circuit 10 and the current regulation circuit 20 to input the first DC current; the second end of the ninth resistor R9 and the first end of the tenth resistor R10 together serve as the sampling voltage output terminal of the voltage sampling circuit 50, and are connected to the boost circuit 10 to output the sampling voltage; the second end of the tenth resistor R10 is connected to the power supply ground.

[0106] The first filter circuit 60 includes a fourteenth resistor R14, a fifteenth resistor R15, an eighth capacitor C8, and a ninth capacitor C9.

[0107] The first end of the fifteenth resistor R15 serves as the second PWM control signal input terminal of the first filter circuit 60 to input the second PWM control signal; the second end of the fifteenth resistor R15, the first end of the fourteenth resistor R14, and the first end of the ninth capacitor C9 are connected; the second end of the fourteenth resistor R14 and the first end of the eighth capacitor C8 together serve as the filtered second PWM control signal output terminal of the first filter circuit 60, which is connected to the current adjustment circuit 20 to output the filtered second PWM control signal; the second end of the eighth capacitor C8 and the second end of the ninth capacitor C9 are connected to the power supply ground.

[0108] The interference suppression circuit 70 includes a first ferrite bead B1.

[0109] The first end of the first ferrite bead B1 serves as the input DC power input terminal of the interference suppression circuit 70 to input DC power; the second end of the first ferrite bead B1 serves as the input DC power output terminal of the interference suppression circuit 70 after high-frequency interference suppression, and is connected to the second filter circuit 80 and the boost circuit 10 to output the input DC power after high-frequency interference suppression.

[0110] The second filter circuit 80 includes a first capacitor C1.

[0111] The first terminal of the first capacitor C1 serves as the input terminal of the high-frequency interference suppressed DC power of the second filter circuit 80 and the output terminal of the filtered DC power of the second filter circuit 80. It is connected to the interference suppression circuit 70 and the boost circuit 10 to input the high-frequency interference suppressed DC power and output the filtered DC power. The second terminal of the first capacitor C1 is connected to the power supply ground.

[0112] The interference suppression module includes a second magnetic bead B2.

[0113] The first end of the second magnetic bead B2 serves as the DC input terminal of the interference suppression module, and is connected to the boost circuit 10, the current dimming circuit, and the voltage sampling circuit 50 to input and output DC power; the second end of the second magnetic bead B2 serves as the DC output terminal of the interference suppression module after high-frequency interference suppression, and is connected to the light-emitting component to output the DC power after high-frequency interference suppression.

[0114] The following is based on the working principle. Figure 8 Further explanation is provided below:

[0115] After the duty cycle of the first PWM control signal rises to the first preset value, the duty cycle of the first PWM control signal gradually rises from the first preset value to the second preset value, and the duty cycle of the second PWM control signal gradually decreases from the third preset value to the fourth preset value.

[0116] The first terminal of the first ferrite bead B1 is connected to the input DC power. The first ferrite bead B1 suppresses high-frequency interference of the input DC power and outputs the input DC power after high-frequency interference suppression. The first capacitor C1 filters the input DC power after high-frequency interference suppression and outputs the filtered input DC power to the first terminal of the fourth resistor R4 and the first terminal of the inductor L1. The first terminal of the first resistor R1 is connected to the first PWM control signal. The boost constant current driver U1 controls the first field-effect transistor Q1 to turn on and off based on the first PWM control signal. When the first field-effect transistor Q1 is turned on, the inductor L1 stores energy. The seventh resistor R7 is the peak current sensing resistor. After the voltage across the seventh resistor R7 is higher than the preset threshold voltage, the first field-effect transistor Q1 is turned off. The voltage on the inductor L1 is superimposed with the voltage of the input DC power to achieve boost. The second diode D2 conducts unidirectional conduction of the boosted voltage. The seventh capacitor C7 stores energy according to the unidirectional conduction voltage and outputs the first DC power from the first terminal of the seventh capacitor C7 to the first terminal of the ninth resistor R9 and the first terminal of the eleventh resistor R11.

[0117] The first terminal of the fifteenth resistor R15 is connected to the second PWM control signal. The fourteenth resistor R14, the fifteenth resistor R15, the eighth capacitor C8, and the ninth capacitor C9 filter the second PWM control signal and output the filtered second PWM control signal from the second terminal of the fourteenth resistor R14 and the first terminal of the eighth capacitor C8 to the base of the transistor A1. The collector of the transistor A1 outputs the first PWM signal to the gate of the second field-effect transistor Q2, the first terminal of the twelfth resistor R12, and the first terminal of the thirteenth resistor R13. The second field-effect transistor Q2 is turned on. The second field-effect transistor Q2 and the eleventh resistor R11 shunt the first DC current to generate the output DC current and the second DC current. The output DC current is output to the first terminal of the second ferrite bead B2. The second ferrite bead B2 suppresses high-frequency interference of the output DC current and outputs the high-frequency interference suppressed output DC current to the light-emitting component. The light-emitting component emits light according to the output DC current.

[0118] The source of the second field-effect transistor Q2 outputs a second DC current. The eighth resistor R8 samples the current of the output DC current after high-frequency interference suppression and the current of the second DC current, and outputs the current sampling signal to the current feedback input terminal IF of the boost constant current driver U1. The ninth resistor R9 and the tenth resistor R10 divide the first DC current, and output the sampled voltage from the second terminal of the ninth resistor R9 and the first terminal of the tenth resistor R10 to the voltage feedback input terminal VF of the boost constant current driver U1. The first terminal of the third resistor R3 and the first terminal of the fifth capacitor C5 output a slope compensation signal to the compensation terminal C of the boost constant current driver U1. The boost constant current driver U1 controls the conduction and cutoff of the first field-effect transistor Q1 according to the first PWM control signal, the current sampling signal, the sampled voltage, and the slope compensation signal to realize the boost of the input DC current.

[0119] This application also provides an electronic device that includes the dimming circuit described above.

[0120] 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.

[0121] 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, connected to a light-emitting component, characterized in that, include: A boost circuit, connected to the light-emitting component, is used to receive the input DC power and the first PWM control signal, and boosts the input DC power according to the first PWM control signal to output the first DC power; A current regulation circuit, connected to the light-emitting component and the boost circuit, is used to shunt the first DC current according to the second PWM control signal to output DC current. The light-emitting component is used to emit light according to the output DC power; Wherein, after the duty cycle of the first PWM control signal rises to the first preset value, while the duty cycle of the first PWM control signal gradually rises from the first preset value to the second preset value, the duty cycle of the second PWM control signal gradually decreases from the third preset value to the fourth preset value.

2. The dimming circuit as described in claim 1, characterized in that, The current regulation circuit includes: The first switching module is used to output a first PWM signal according to the second PWM control signal; The second switching module, connected to the first switching module and the boost circuit, is used to shunt the first DC power according to the first PWM signal to output the output DC power.

3. The dimming circuit as described in claim 1, characterized in that, The current regulation circuit is specifically used to shunt the output DC power according to the second PWM control signal, so as to output the output DC power and the second DC power; The dimming circuit also includes: A current sampling circuit, connected to the light-emitting component, the boost circuit, and the current regulation circuit, is used to sample the current of the output DC power and the current of the second DC power to output a current sampling signal. The boost circuit is specifically used to boost the input DC power according to the first PWM control signal and the current sampling signal, so as to output the first DC power.

4. The dimming circuit as described in claim 3, characterized in that, The current sampling circuit includes an eighth resistor; The first end of the eighth resistor serves as the output DC input terminal, the second DC input terminal, and the current sampling signal output terminal of the current sampling circuit. It is connected to the light-emitting component, the boost circuit, and the current regulation circuit to input the output DC and the second DC and output the current sampling signal. The second end of the eighth resistor is connected to the power supply ground.

5. The dimming circuit as described in claim 1, characterized in that, Also includes: A slope compensation circuit, connected to the boost circuit, is used to output a slope compensation signal; The boost circuit specifically boosts the input DC power based on the first PWM control signal and the slope compensation signal to output the first DC power.

6. The dimming circuit as described in claim 1, characterized in that, Also includes: A voltage sampling circuit, connected to the light-emitting component, the boost circuit, and the current regulation circuit, is used to sample the voltage of the first DC power supply to output a sampled voltage. The boost circuit is specifically used to boost the input DC power according to the first PWM control signal and the sampled voltage, so as to output the first DC power.

7. The dimming circuit as described in claim 1, characterized in that, Also includes: The first filtering circuit is connected to the current regulating circuit and is used to filter the second PWM control signal to output the filtered second PWM control signal. The current regulation circuit is specifically used to output the output DC power according to the filtered second PWM control signal.

8. The dimming circuit as described in claim 1, characterized in that, Also includes: An interference suppression circuit, connected to the boost circuit, is used to suppress high-frequency interference in the input DC power so as to output the input DC power after high-frequency interference suppression. The second filtering circuit is connected to the interference suppression circuit and the boost circuit, and is used to filter the input DC power after high-frequency interference suppression, so as to output the filtered input DC power. The boost circuit is specifically used to boost the filtered input DC power according to the first PWM control signal to output the first DC power.

9. The dimming circuit as described in claim 1, characterized in that, The boost circuit includes a boost constant current driver, a first field-effect transistor, an inductor, a first diode, a second diode, a first resistor, a second resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a sixteenth resistor, a seventeenth resistor, a first capacitor, a second capacitor, a third capacitor, a sixth capacitor, a seventh capacitor, a tenth capacitor, and an eleventh capacitor. The first end of the first resistor serves as the first PWM control signal input terminal of the boost circuit to input the first PWM control signal; the second end of the first resistor, the pulse width modulation input terminal PWM of the boost constant current driver, the first end of the second resistor, and the first end of the second capacitor are connected; the current feedback input terminal of the boost constant current driver serves as the current sampling signal input terminal of the boost circuit and is connected to the current adjustment circuit, the light-emitting component, and the voltage sampling circuit to receive the current sampling signal. The voltage feedback input terminal of the boost constant current driver serves as the sampling voltage input terminal of the boost circuit and is connected to the voltage sampling circuit to receive the sampling voltage. The compensation terminal of the boost constant current driver serves as the ramp compensation signal input terminal of the boost circuit and is connected to the ramp compensation circuit to input the ramp compensation signal; the first terminal of the fourth resistor and the first terminal of the inductor together serve as the input DC power input terminal of the boost circuit to input the input DC power. The input voltage terminal of the boost constant current driver, the second terminal of the fourth resistor, and the first terminal of the sixth capacitor are connected. The driving terminal of the boost constant current driver, the cathode of the first diode, and the first terminal of the fifth resistor are connected. The anode of the first diode and the first terminal of the sixth resistor are connected. The second terminals of the fifth resistor and the sixth resistor are connected to the gate of the first field-effect transistor. The second terminal of the inductor, the anode of the second diode, the first terminal of the tenth capacitor, the first terminal of the eleventh capacitor, and the drain of the first field-effect transistor are connected. The current detection terminal of the boost constant current driver, the source of the first field-effect transistor, and the first terminal of the seventh resistor are connected. The first terminal of the sixteenth resistor, the cathode of the second diode, and the first terminal of the seventh capacitor together serve as the first DC output terminal of the boost circuit, which is connected to the light-emitting component, the current adjustment circuit, and the light-emitting component to output the first DC current. The second end of the sixteenth resistor is connected to the second end of the tenth capacitor, the second end of the eleventh capacitor is connected to the first end of the seventeenth resistor, the power supply terminal of the boost constant current driver and the first end of the third capacitor are connected to the first power supply, and the second end of the second resistor, the ground terminal of the boost constant current driver, the second end of the second capacitor, the second end of the third capacitor, the second end of the sixth capacitor, the second end of the seventh resistor, the second end of the seventeenth resistor and the second end of the seventh capacitor are connected to the power supply ground.

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

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