Multistage dimming circuit and lighting equipment

Abstract

The invention discloses a multi-stage dimming circuit and lighting equipment. The multi-stage dimming circuit comprises a first sampling switch module, a second sampling switch module, a sampling module and a control module. The first sampling switch module and the second sampling switch module are controlled by setting a preset threshold value, and two sampling channels of the sampling module are matched, so that sampling can be carried out when the working current of the light emitting module is small, fine dimming is carried out according to the first sampling current, and the working efficiency is improved. In addition, sampling can be carried out when the working current of the light emitting module is a large current so as to give consideration to large-current dimming according to the second sampling current and increase the dynamic range during dimming, so that high-precision dimming can be realized according to the first sampling current and the second sampling current under the condition of giving consideration to high-resolution dimming.

Description

Technical Field

[0001] This application belongs to the field of lighting technology, and particularly relates to a multi-level dimming circuit and a lighting device. Background Art

[0002] Currently, traditional LED drivers usually adopt single-stage current sampling technology to adjust the brightness through PWM (pulse width modulation) or analog voltage. However, single-stage sampling has problems such as insufficient dynamic range during large-current dimming and low dimming accuracy during small-current dimming, making it difficult to achieve ultra-high-resolution dimming. Limited by hardware conditions (such as the number of bits of signals that the chip can process, the accuracy of analog-to-digital conversion, etc.), it is difficult to balance the requirements of large-current constant-current drive and small-current fine dimming, resulting in limited application scenarios and high hardware requirements. Summary of the Invention

[0003] The purpose of this application is to provide a multi-level dimming circuit and a lighting device, aiming to solve the problem that traditional lighting devices have difficulty in balancing high-resolution dimming and dimming accuracy.

[0004] The first aspect of the embodiments of this application provides a multi-level dimming circuit for regulating the operating current of a light-emitting module. The multi-level dimming circuit includes: a first sampling switch module, a second sampling switch module, a sampling module, and a control module; the first sampling switch module is connected between the light-emitting module and the first input end of the sampling module; the second sampling switch module is connected between the light-emitting module and the second input end of the sampling module; the sampling module is configured to sample the current at the first input end and amplify it at a first magnification to obtain a first sampled current, or to sample the current at the second input end and amplify it at a second magnification to obtain a second sampled current, where the first magnification is greater than the second magnification; the control module is respectively connected to the first sampling switch module, the second sampling switch module, and the sampling module, and the control module is configured to control the first sampling switch module to conduct and the second sampling switch module to turn off when the desired current is less than a preset threshold, and to control the first sampling switch module to turn off and the second sampling switch module to conduct when the desired current is greater than the preset threshold.

[0005] In one embodiment, the sampling module includes a first sampling resistor R1, a second sampling resistor R2, a first amplifier U1, and a second amplifier U2; a first end of the first sampling resistor R1 is connected to an output end of the first sampling switch module, a second end of the first sampling resistor R1 is grounded, a first end of the second sampling resistor R2 is connected to an output end of the second sampling switch module, a second end of the second sampling resistor R2 is connected to the first end of the first sampling resistor R1, an input end of the first amplifier U1 is connected to the first end of the first sampling resistor R1, an input end of the second amplifier U2 is connected to the first end of the second sampling resistor R2, output ends of the first amplifier U1 and the second amplifier U2 are both connected to the control module, the first amplifier U1 is configured to amplify the voltage at the first end of the first sampling resistor R1 according to a first amplification factor, and the second amplifier U2 is configured to amplify the voltage at the first end of the second sampling resistor R2 according to a second amplification factor; the first sampling resistor R1 is greater than the second sampling resistor R2, and the first amplification factor is less than the second amplification factor.

[0006] In one embodiment, the first sampling switch module includes a first switching device Q1, a first end of the first switching device Q1 is connected to an output end of the light-emitting module, a second end of the first switching device Q1 is connected to a first input end of the sampling module, and a control end of the first switching device Q1 is connected to the control module; the second sampling switch module includes a second switching device Q2, a first end of the second switching device Q2 is connected to the output end of the light-emitting module, a second end of the second switching device Q2 is connected to a second input end of the sampling module, and a control end of the second switching device Q2 is connected to the control module.

[0007] In one embodiment, the multi-stage dimming circuit further includes a power module, and the power module is respectively connected to the light-emitting module and the control module; the control module is further configured to obtain an operating current of the light-emitting module according to the first sampling current and the second sampling current, and adjust an output power of the power module according to the operating current and the desired current.

[0008] In one embodiment, the power module includes a first capacitor C1, a second capacitor C2, a unidirectional conductor D1, an inductor L1, and a power switch Q3; a first end of the first capacitor C1 is configured to receive an input voltage and is connected to a first end of the inductor L1, a second end of the first capacitor C1 is grounded, a second end of the inductor L1 is connected to a first end of the power switch Q3 and an input end of the unidirectional conductor D1, a first end of the second capacitor C2 is connected to an output end of the unidirectional conductor D1, a second end of the power switch Q3 and a second end of the second capacitor C2 are grounded, a control end of the power switch Q3 is connected to the control module, and an output end of the unidirectional conductor D1 is connected to an input end of the light-emitting module 20.

[0009] In one embodiment, the multi-level dimming circuit further includes a voltage feedback module, the voltage feedback module is respectively connected to an output end of the power module and the control module, and the voltage feedback module is configured to generate and transmit a voltage feedback signal to the control module according to a voltage at the output end of the power module.

[0010] In one embodiment, the control module includes a control unit and a driving unit; the control unit is connected to the sampling module, and the control unit is configured to: obtain an operating current of the light-emitting module according to the first sampled current or the second sampled current; the driving unit is respectively connected to the first sampling switch module, the second sampling switch module, and the control unit, and the control unit is further configured to control the driving unit to transmit a first control signal and a second control signal to the first sampling switch module and the second sampling switch module respectively, the first control signal is used to control the first sampling switch module to conduct, and the second control signal is used to control the second sampling switch module to conduct.

[0011] In one embodiment, the control module is configured to: in a case where the desired current increases, when the desired current is equal to the preset threshold, output the second control signal and stop outputting the first control signal; in a case where the desired current decreases, when the desired current is equal to the preset threshold, output the first control signal and stop outputting the second control signal.

[0012] A second aspect of the embodiments of the present application provides a lighting device, including a light-emitting module and the multi-level dimming circuit as described above, the multi-level dimming circuit is connected to the light-emitting module and is configured to adjust an operating current of the light-emitting module.

[0013] In one embodiment, the lighting device further includes a host computer, the host computer is connected to the multi-level dimming circuit, and the host computer is configured to provide a control signal corresponding to the desired current to the multi-level dimming circuit.

[0014] The beneficial effects of the embodiments of the present application compared with the prior art are as follows: the sampling module samples and amplifies the current at the first input end and the current at the first input end at different magnification factors respectively, so as to form two sampling channels. When the data processing capacity of the control module is limited, the sampling range and sampling accuracy of a single sampling channel are negatively correlated.

[0015] By setting a preset threshold to control the first sampling switch module and the second sampling switch module, and cooperating with the two sampling channels of the sampling module, it is possible to sample when the working current of the light-emitting module is a small current, so as to perform fine dimming according to the first sampling current, and it is also possible to sample when the working current of the light-emitting module is a large current, so as to take into account large-current dimming according to the second sampling current, increasing the dynamic range during dimming. Thus, it is possible to achieve high-precision dimming according to the first sampling current and the second sampling current while taking into account high-resolution dimming. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of a multi-stage dimming circuit provided by an embodiment of the present application;

[0017] Figure 2 It is a circuit schematic diagram of a multi-stage dimming circuit provided by an embodiment of the present application;

[0018] Figure 3 It is a schematic diagram of a lighting device provided by an embodiment of the present application. Detailed Embodiments

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clear and understandable, the present application will be further described in detail below with reference to the 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.

[0020] 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.

[0021] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 construed as a limitation to the present application.

[0022] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0023] Figure 1 The schematic diagram of a multi-level dimming circuit provided by an embodiment of this application is shown. For the sake of convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0024] A multi-level dimming circuit 10 is used to adjust the operating current of a light-emitting module 20. It can be understood that by adjusting the operating current of the light-emitting module 20, the brightness of the light-emitting module 20 can be adjusted.

[0025] The multi-level dimming circuit 10 includes: a first sampling switch module 100, a second sampling switch module 200, a sampling module 300, and a control module 400.

[0026] The first sampling switch module 100 is connected between the light-emitting module 20 and the first input terminal of the sampling module 300. The second sampling switch module 200 is connected between the light-emitting module 20 and the second input terminal of the sampling module 300;

[0027] The sampling module 300 is used to sample the current at the first input terminal and amplify it at a first magnification to obtain a first sampled current, or to sample the current at the second input terminal and amplify it at a second magnification to obtain a second sampled current, where the first magnification is greater than the second magnification.

[0028] The control module 400 is respectively connected to the first sampling switch module 100, the second sampling switch module 200, and the sampling module 300. The control module 400 is used to control the first sampling switch module 100 to conduct and the second sampling switch module 200 to turn off when the desired current is less than the preset threshold, and to control the first sampling switch module 100 to turn off and the second sampling switch module 200 to conduct when the desired current is less than the preset threshold.

[0029] It should be noted that by sampling and amplifying the current at the first input terminal and the current at the first input terminal at different magnifications through the sampling module 300, two sampling channels can be formed. When the data processing ability of the control module 400 is limited, the sampling range and sampling accuracy of a single sampling channel are negatively correlated.

[0030] By setting a preset threshold and coordinating with the two sampling channels of the sampling module 300, sampling can be performed when the operating current of the light-emitting module 20 is a small current for fine dimming, or sampling can be performed when the operating current of the light-emitting module 20 is a large current to take into account large-current dimming, increasing the dynamic range during dimming. Thus, high-precision dimming can be achieved according to the first sampling current and the second sampling current while taking into account high-resolution dimming.

[0031] It can be understood that the higher the sampling accuracy, the more accurately the operating current of the light-emitting module 20 can be feedback-controlled, and correspondingly, the higher the dimming accuracy.

[0032] Specifically, the light-emitting module 20 may include an LED lamp group.

[0033] In some embodiments, the preset threshold is 500 mA, the current range of the first input end of the sampling module 300 is 0 - 500 mA, and the current range of the second input end of the sampling module 300 is 500 mA - 20 A.

[0034] In one embodiment, as Figure 2 shown, the sampling module 300 includes a first sampling resistor R1, a second sampling resistor R2, a first amplifier U1, and a second amplifier U2.

[0035] The first end of the first sampling resistor R1 is connected to the output end of the first sampling switch module 100, the second end of the first sampling resistor R1 is grounded, the first end of the second sampling resistor R2 is connected to the output end of the second sampling switch module 200, the second end of the second sampling resistor R2 is connected to the first end of the first sampling resistor R1, the input end of the first amplifier U1 is connected to the first end of the first sampling resistor R1, the input end of the second amplifier U2 is connected to the first end of the second sampling resistor R2, the output ends of the first amplifier U1 and the second amplifier U2 are both connected to the control module 400. The first amplifier U1 is used to amplify the voltage at the first end of the first sampling resistor R1 according to the first amplification factor, and the second amplifier U2 is used to amplify the voltage at the first end of the second sampling resistor R2 according to the second amplification factor.

[0036] The first sampling resistor R1 is greater than the second sampling resistor R2, and the first amplification factor is less than the second amplification factor.

[0037] Adopting a smaller second sampling resistor R2 facilitates reducing the impedance of the sampling module 300 by turning on the second sampling switch module 200 and turning off the first sampling switch module 100 when the desired current is greater than the preset threshold, so as to facilitate the large-current drive of the light-emitting module 20.

[0038] Adopting a larger first sampling resistor R1 can make the voltage at the input end of the first amplifier U1 larger when the expected current is greater than the preset threshold, so that sampling can be performed in a way with a smaller magnification, avoiding the situation of distorted sampling results and excessive errors caused by too large a magnification.

[0039] By connecting the first sampling resistor R1 in series with the second sampling resistor R2, it can be made that when switching from the first sampling switch module 100 being turned on and the second sampling switch module 200 being turned off to the first sampling switch module 100 being turned off and the second sampling switch module 200 being turned on, the second amplifier U2 keeps being powered on in advance and outputs, reducing the fluctuation of the sampling current during switching and avoiding the light-emitting module 20 from flashing.

[0040] Specifically, both the first amplifier U1 and the second amplifier U2 can adopt corresponding amplifier chips or can adopt an amplifier circuit composed of operational amplifiers. This embodiment does not limit it.

[0041] It can be understood that the first magnification is specifically determined jointly by the first sampling resistor R1 and the first amplification factor, and the second magnification is specifically determined jointly by the second sampling resistor R2 and the second amplification factor.

[0042] In some embodiments, the second sampling resistor R2 is 1 mΩ, the second amplification factor is 100, the first sampling resistor R1 is 500 mΩ, and the first amplification factor is 10.

[0043] In one embodiment, the first sampling switch module 100 includes a first switching device Q1. The first end of the first switching device Q1 is connected to the output end of the light-emitting module 20, the second end of the first switching device Q1 is connected to the first input end of the sampling module 300, and the control end of the first switching device Q1 is connected to the control module 400;

[0044] The second sampling switch module 200 includes a second switching device Q2. The first end of the second switching device Q2 is connected to the output end of the light-emitting module 20, the second end of the second switching device Q2 is connected to the second input end of the sampling module 300, and the control end of the second switching device Q2 is connected to the control module 400.

[0045] It can be understood that the control module 400 can control the conduction and cutoff of the first switching device Q1 and the second switching device Q2 by outputting corresponding level signals.

[0046] Specifically, both the first switching device Q1 and the second switching device Q2 can be N-type MOS transistors.

[0047] In one embodiment, as Figure 2 shown, the control module 400 includes a control unit 410 and a driving unit 420.

[0048] The control unit 410 is connected to the sampling module 300, and the control unit 410 is configured to: obtain the operating current of the light-emitting module 20 according to the first sampling current or the second sampling current.

[0049] The driving unit 420 is respectively connected to the first sampling switch module 100, the second sampling switch module 200 and the control unit 410. The control unit 410 is further configured to control the driving unit 420 to transmit a first control signal and a second control signal to the first sampling switch module 100 and the second sampling switch module 200 respectively. The first control signal is used to control the first sampling switch module 100 to conduct, and the second control signal is used to control the second sampling switch module 200 to conduct.

[0050] Wherein, the control unit 410 may include a microcontroller (Microcontroller Unit; MCU), and the driving unit 420 may include a Pulse Width Modulation (PWM) chip.

[0051] When the sampling current is an analog signal, the control unit 410 may further perform analog-to-digital conversion on the first sampling current and the second sampling current to obtain corresponding digital signals.

[0052] In one embodiment, as Figure 2 shown, the multi-level dimming circuit 10 further includes a power module 500. The power module 500 is respectively connected to the light-emitting module 20 and the control module 400; the control module 400 is further configured to obtain the operating current of the light-emitting module according to the first sampling current and the second sampling current, and adjust the output power of the power module 500 according to the operating current and the desired current.

[0053] It can be understood that by adjusting the output power of the power module 500, the voltage and current provided to the light-emitting module 20 can be changed, and constant current driving of the light-emitting module 20 can be achieved.

[0054] In one embodiment, the multi-level dimming circuit 10 further includes a voltage feedback module 600. The voltage feedback module 600 is respectively connected to the output terminal of the power module 500 and the control module 400. The voltage feedback module 600 is configured to generate and transmit a voltage feedback signal to the control module 400 according to the voltage at the output terminal of the power module 500.

[0055] The control module 400 can implement over-voltage protection according to the voltage feedback signal. When the voltage is too large, the first sampling switch module 100 and the second sampling switch module 200 are controlled to turn off simultaneously.

[0056] Specifically, the power module 500 includes a first capacitor C1, a second capacitor C2, a unidirectional conductor D1, an inductor L1, and a power switch Q3.

[0057] The first end of the first capacitor C1 is used to connect to the input voltage and is connected to the first end of the inductor L1. The second end of the first capacitor C1 is grounded. The second end of the inductor L1 is connected to the first end of the power switch Q3 and the input end of the unidirectional conductor D1. The first end of the second capacitor C2 is connected to the output end of the unidirectional conductor D1. The second end of the power switch Q3 and the second end of the second capacitor C2 are grounded. The control end of the power switch Q3 is connected to the control module 400 (drive unit 420). The output end of the unidirectional conductor D1 is connected to the input end of the light-emitting module 20 and the voltage feedback module 600.

[0058] The control module 400 can send a first pulse-width modulation signal to the control end of the power switch Q3. By controlling the duty cycle of the first pulse-width modulation signal, the voltage supplied to the light-emitting module 20 can be adjusted.

[0059] In one embodiment, the control module 400 is configured to: in the case of an increasing desired current, when the desired current is equal to the preset threshold, output a second control signal and stop outputting the first control signal; in the case of a decreasing desired current, when the desired current is equal to the preset threshold, output the first control signal and stop outputting the second control signal.

[0060] The control module 400 can, according to the change of the desired current, complete the switching between the first sampling switch module 100 and the second sampling switch module 200 when the desired current is equal to the preset threshold.

[0061] It should be noted that in the case where both the sampling module 300 and the power module 500 are analog circuits, PWM high-frequency interference can be eliminated, which is suitable for an electromagnetic-sensitive environment (such as a radio frequency laboratory) to achieve flicker-free lighting.

[0062] Exemplarily, in one embodiment, the second sampling resistor R2 is 1 mΩ, the second amplification factor is 100, the first sampling resistor R1 is 500 mΩ, the first amplification factor is 10; the preset threshold is 500 mA; the maximum control current upper limit of the second multi-level dimming circuit 10 is 20 A. The operating voltages of the first amplifier U1 and the second amplifier U2 are 3300 mV, and the accuracy of the control module 400 (control unit 410) for analog-to-digital conversion of the sampled current is 12 bits.

[0063] It can be calculated that the resolution of the second sampled current output by the second amplifier U2 is: 20 A / (20 A * 1 mΩ * 100) = 10 mA / mV.

[0064] The resolution of the first sampled current output by the first amplifier U1 is: 500 mA / (500 mA * 500 mΩ * 10) = 0.2 mA / mV.

[0065] It can be seen that the resolution of the first sampled current is 50 times higher than that of the second sampled current, enabling more precise current regulation at low operating currents.

[0066] Correspondingly, the equivalent precision of the analog-to-digital converter (ADC) of the control module 400 is: log(1 mΩ * 20 A * 100 / 3300 mV * 12 bit, 2) + log(20 A / 500 mA, 2) + log(500 mΩ * 500 mA * 10 / 3300 mV * 4096 / 4096, 2) = 16.199 bit; in this embodiment, the equivalent precision of the analog-to-digital converter of the control module 400 can be increased to more than 16 bit, thus achieving high-precision analog dimming.

[0067] Figure 3 The figure shows a schematic diagram of a lighting device provided by an embodiment of the present application. For ease of explanation, only the parts relevant to this embodiment are shown and are described in detail as follows:

[0068] A lighting device 30 includes a light-emitting module 20 and a multi-level dimming circuit 10 as described in any of the above embodiments. The multi-level dimming circuit 10 is connected to the light-emitting module 20 and is used to adjust the operating current of the light-emitting module 20.

[0069] In one embodiment, the lighting device 30 further includes a host computer 40. The host computer 40 is connected to the multi-level dimming circuit 10, and the host computer 40 is used to provide a control signal corresponding to the desired current to the multi-level dimming circuit 10.

[0070] The host computer 40 can obtain the desired current and output the corresponding control signal by means of human-computer interaction or communication with other devices.

[0071] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional units and modules according to needs, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of the functional units and modules are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0072] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0073] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application and should all be included in the protection scope of the present application.

Claims

1. A multi-level dimming circuit (10), characterized in that, For regulating the working current of the light-emitting module (20), the multi-stage dimming circuit (10) includes: a first sampling switch module (100), a second sampling switch module (200), a sampling module (300), and a control module (400); The first sampling switch module (100) is connected between the light-emitting module (20) and the first input end of the sampling module (300); The second sampling switch module (200) is connected between the light-emitting module (20) and the second input end of the sampling module (300); The sampling module (300) is configured to sample the current at the first input end and amplify it by a first magnification to obtain a first sampled current, or to sample the current at the second input end and amplify it by a second magnification to obtain a second sampled current, where the first magnification is greater than the second magnification; The control module (400) is respectively connected to the first sampling switch module (100), the second sampling switch module (200), and the sampling module (300). The control module (400) is configured to control the first sampling switch module (100) to conduct and the second sampling switch module (200) to turn off when the desired current is less than a preset threshold, and to control the first sampling switch module (100) to turn off and the second sampling switch module (200) to conduct when the desired current is greater than the preset threshold.

2. The multi-stage dimming circuit (10) according to claim 1, characterized in that, The sampling module (300) includes a first sampling resistor R1, a second sampling resistor R2, a first amplifier U1, and a second amplifier U2; The first end of the first sampling resistor R1 is connected to the output end of the first sampling switch module (100), the second end of the first sampling resistor R1 is grounded, the first end of the second sampling resistor R2 is connected to the output end of the second sampling switch module (200), the second end of the second sampling resistor R2 is connected to the first end of the first sampling resistor R1, the input end of the first amplifier U1 is connected to the first end of the first sampling resistor R1, the input end of the second amplifier U2 is connected to the first end of the second sampling resistor R2, the output ends of the first amplifier U1 and the second amplifier U2 are both connected to the control module (400). The first amplifier U1 is configured to amplify the voltage at the first end of the first sampling resistor R1 according to a first amplification factor, and the second amplifier U2 is configured to amplify the voltage at the first end of the second sampling resistor R2 according to a second amplification factor; The first sampling resistor R1 is greater than the second sampling resistor R2, and the first amplification factor is less than the second amplification factor.

3. The multi-stage dimming circuit (10) according to claim 1, characterized in that, The first sampling switch module (100) includes a first switching device Q1. The first end of the first switching device Q1 is connected to the output end of the light-emitting module (20), the second end of the first switching device Q1 is connected to the first input end of the sampling module (300), and the control end of the first switching device Q1 is connected to the control module (400); The second sampling switch module (200) includes a second switching device Q2. A first end of the second switching device Q2 is connected to an output end of the light-emitting module (20), a second end of the second switching device Q2 is connected to a second input end of the sampling module (300), and a control end of the second switching device Q2 is connected to the control module (400).

4. The multi-stage dimming circuit (10) according to any one of claims 1 to 3, characterized in that, The multi-level dimming circuit (10) further includes a power module (500). The power module (500) is respectively connected to the light-emitting module (20) and the control module (400); The control module (400) is further configured to obtain an operating current of the light-emitting module according to the first sampling current and the second sampling current, and adjust an output power of the power module (500) according to the operating current and the desired current.

5. The multi-stage dimming circuit (10) according to claim 4, wherein The power module (500) includes a first capacitor C1, a second capacitor C2, a unidirectional conductor D1, an inductor L1, and a power switch Q3; A first end of the first capacitor C1 is used for connecting to an input voltage and is connected to a first end of the inductor L1. A second end of the first capacitor C1 is grounded. A second end of the inductor L1 is connected to a first end of the power switch Q3 and an input end of the unidirectional conductor D1. A first end of the second capacitor C2 is connected to an output end of the unidirectional conductor D1. A second end of the power switch Q3 and a second end of the second capacitor C2 are grounded. A control end of the power switch Q3 is connected to the control module (400), and an output end of the unidirectional conductor D1 is connected to an input end of the light-emitting module 20.

6. The multi-stage dimming circuit (10) according to claim 4, characterized in that, The multi-level dimming circuit (10) further includes a voltage feedback module (600). The voltage feedback module (600) is respectively connected to an output end of the power module (500) and the control module (400). The voltage feedback module (600) is configured to generate and transmit a voltage feedback signal to the control module (400) according to a voltage at the output end of the power module (500).

7. The multi-stage dimming circuit (10) according to claim 4, characterized in that, The control module (400) includes a control unit (410) and a driving unit (420); The control unit (410) is connected to the sampling module (300). The control unit (410) is configured to: obtain an operating current of the light-emitting module (20) according to the first sampling current or the second sampling current; The driving unit (420) is respectively connected to the first sampling switch module (100), the second sampling switch module (200), and the control unit (410). The control unit (410) is further configured to control the driving unit (420) to respectively transmit a first control signal and a second control signal to the first sampling switch module (100) and the second sampling switch module (200). The first control signal is used to control the first sampling switch module (100) to conduct, and the second control signal is used to control the second sampling switch module (200) to conduct.

8. The multi-stage dimming circuit (10) according to claim 7, wherein, The control module (400) is configured to: in the case where the desired current increases, when the desired current is equal to the preset threshold, output the second control signal and stop outputting the first control signal; in the case where the desired current decreases, when the desired current is equal to the preset threshold, output the first control signal and stop outputting the second control signal.

9. A lighting device (30), characterized in that, It includes a light-emitting module (20) and a multi-level dimming circuit (10) according to any one of claims 1 to 8. The multi-level dimming circuit (10) is connected to the light-emitting module (20) and is used to adjust the operating current of the light-emitting module (20).

10. The lighting device (30) according to claim 9, characterized in that, The lighting device (30) further includes a host computer (40). The host computer (40) is connected to the multi-level dimming circuit (10), and the host computer (40) is used to provide a control signal corresponding to the desired current to the multi-level dimming circuit (10).

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