Dimming circuit and device

Abstract

The utility model discloses a dimming circuit and equipment, and relates to the technical field of beauty equipment. The dimming circuit comprises a power supply input end, a power supply control circuit, a switching circuit, a main control circuit and a push-pull circuit. Wherein the power supply control circuit can receive the power supply from the power supply input end and transmit the power supply to the first power supply end of the lamp. Through the power supply control circuit, the main control circuit can control input / stop of a power supply. When a power supply is input, the main control circuit can output a PWM control signal for controlling dimming, and the push-pull circuit can control the conduction time of the switching circuit according to the PWM control signal, so that the grounding time of the second power supply end of the lamp is controlled, and the average power of the lamp is adjusted. The dimming circuit has the advantages of high dimming response speed, low power consumption, smoother dimming curve, low possibility of large current impact and low cost.

Description

TECHNICAL FIELD

[0001] The utility model relates to cosmetic equipment technical field, especially a light adjusting circuit and equipment. BACKGROUND

[0002] In modern beauty and skin care equipment, skin rejuvenation instrument as a kind of device using near infrared light (NIR) for skin care, because it can effectively act on skin deep, and bring the skin effect of bright white and thorough, and is widely concerned. The cosmetic equipment usually adopts the near infrared spectrum of specific wavelength range (900-1800nm, wave crest 1300nm), to ensure the best penetration depth and treatment effect. In order to produce these specific wavelength light, the existing skin rejuvenation instrument generally adopts the mode of driving tungsten lamp through DC-DC step-down chip.

[0003] However, the mode of driving tungsten lamp through DC-DC step-down chip exists the problems of large power consumption, non-smooth dimming curve, large current impact risk and high cost. CONTENT OF UTILITY MODEL

[0004] The utility model aims at providing a light adjusting circuit, which aims at solving the problems of large power consumption, non-smooth dimming curve, large current impact risk and high cost existing in the light adjusting mode of DC-DC step-down chip.

[0005] To achieve the above-mentioned purpose, the light adjusting circuit provided by the utility model comprises:

[0006] A power supply input end for inputting power supply;

[0007] A power supply control circuit, one end of the power supply control circuit is connected with the power supply input end, and the other end of the power supply control circuit is used for connecting the first power supply end of the lamp;

[0008] A switching circuit, the first end of the switching circuit is used for connecting the second power supply end of the lamp, the second end of the switching circuit is grounded, and the switching circuit is used for controlling the grounding state of the lamp;

[0009] A main control circuit, the main control circuit is connected with the controlled end of the power supply control circuit, and the main control circuit is used for controlling the power supply control circuit to input / stop inputting the power supply; the main control circuit is also used for outputting PWM control signal;

[0010] a push-pull circuit, a signal input end of the push-pull circuit being connected with the master control circuit, a signal output end of the push-pull circuit being connected with a controlled end of the switch circuit, and a power supply end of the push-pull circuit being connected with a first end of the switch circuit; the push-pull circuit is used for controlling a conduction time of the switch circuit according to the PWM control signal, so as to adjust an average power size of the lamp.

[0011] In an embodiment, the push-pull circuit comprises a first triode, a second triode and a third triode.

[0012] The base of the first triode is the signal input end of the push-pull circuit, the emitter of the first triode is grounded, the collector of the first triode, the collector of the second triode, the base of the second triode, the base of the third triode and the first power supply end of the lamp are connected, the emitter of the second triode, the emitter of the third triode and the controlled end of the switch circuit are connected, and the collector of the third triode is grounded.

[0013] In an embodiment, the push-pull circuit further comprises a first resistor, a second resistor and a first diode.

[0014] The emitter of the second triode, the emitter of the third triode, the anode of the first diode and one end of the second resistor are connected, the cathode of the first diode and one end of the first resistor are connected, the other end of the first resistor, the other end of the second resistor and the controlled end of the switch circuit are connected.

[0015] In an embodiment, the switch circuit comprises a first MOS tube, the gate of the first MOS tube is connected with the signal output end of the push-pull circuit, the drain of the first MOS tube is connected with the second power supply end of the lamp, and the source of the first MOS tube is grounded.

[0016] In an embodiment, the first MOS tube is a power MOS tube.

[0017] In an embodiment, the power supply input end comprises a battery power supply input end for inputting a battery power supply and an adapter power supply input end for inputting an adapter power supply, and the power supply control circuit comprises:

[0018] a first power supply control circuit, a first end of the first power supply control circuit being connected with the battery power supply input end, a second end of the first power supply control circuit being connected with the first power supply end of the lamp, a controlled end of the first power supply control circuit being connected with the master control circuit, and the first power supply control circuit being used for inputting / stopping inputting the battery power supply according to a first power supply control signal output by the master control circuit;

[0019] a second power supply control circuit, a first end of the second power supply control circuit is connected with the adapter power input end, a second end of the second power supply control circuit is connected with the first power supply end of the lamp, a controlled end of the second power supply control circuit is connected with the master control circuit, and the second power supply control circuit is used for inputting / stopping inputting the adapter power supply according to a second power supply control signal output by the master control circuit.

[0020] In an embodiment, the first power supply control circuit comprises a fourth transistor, a second MOS tube and a third resistor; wherein a base of the fourth transistor is the controlled end of the first power supply control circuit, a collector of the fourth transistor, a gate of the second MOS tube and one end of the third resistor are connected, an emitter of the fourth transistor is grounded, the other end of the third resistor, a drain of the second MOS tube and the battery power input end are connected, a source of the second MOS tube is connected with the first power supply end of the lamp; and / or,

[0021] the second power supply control circuit comprises a fifth transistor, a third MOS tube and a fourth resistor; wherein a base of the fifth transistor is the controlled end of the second power supply control circuit, a collector of the fifth transistor, a gate of the third MOS tube and one end of the fourth resistor are connected, an emitter of the fifth transistor is grounded, the other end of the fourth resistor, a drain of the third MOS tube and the adapter power input end are connected, a source of the third MOS tube is connected with the first power supply end of the lamp.

[0022] In an embodiment, the dimming circuit further comprises:

[0023] a voltage detection circuit, a detection end of the voltage detection circuit is connected with the second power supply end of the lamp, a signal output end of the voltage detection circuit is connected with the master control circuit, and the voltage detection circuit is used for detecting the voltage of the second power supply end of the lamp and outputting a corresponding detection signal;

[0024] the master control circuit is further used for determining the open circuit state of the lamp according to the detection signal.

[0025] In an embodiment, the voltage detection circuit comprises a fifth resistor, a sixth resistor, a seventh resistor and a first capacitor;

[0026] wherein one end of the sixth resistor is connected with the second power supply end of the lamp, the other end of the sixth resistor, one end of the fifth resistor and one end of the seventh resistor are connected, the other end of the seventh resistor and one end of the first capacitor are connected with the signal output end of the voltage detection circuit, and the other end of the fifth resistor and the other end of the first capacitor are grounded.

[0027] The utility model discloses a kind of equipment, including lamp and the light modulation circuit as described above.

[0028] The utility model technical scheme adopts a light modulation circuit, including power supply input end, power supply control circuit, switching circuit, main control circuit and push-pull circuit. Among them, power supply control circuit can receive the power supply from power supply input end, and pass it to the first power supply end of lamp. Through power supply control circuit, main control circuit can control input / stop input power supply. When input power supply, main control circuit can output PWM control signal for controlling light modulation, push-pull circuit can control the on-time of switching circuit according to PWM control signal, to control the grounding time of the second power supply end of lamp, to adjust the average power size of lamp. Compared with the mode of existing light modulation through DC-DC step-down chip, the utility model realizes light modulation through relatively simple circuit, and power consumption is lower, and cost is lower, and light modulation is controlled through push-pull circuit and switching circuit, and response speed is faster, and light modulation curve is relatively smooth, realizes light modulation through PWM control signal, and light modulation curve is relatively smooth, and it is not easy to appear large current impact. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to the structure shown in these drawings without creative labor.

[0030] Figure 1 The structure diagram of the light modulation circuit embodiment provided by the utility model is shown.

[0031] Figure 2 The electronic circuit diagram of still another light modulation circuit embodiment provided by the utility model is shown.

[0032] EXPLANATION OF DRAWINGS:

[0033]

[0034] The realization of the utility model, functional characteristics and advantages will be further explained with reference to the drawings by combining embodiments. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present utility model.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present utility model are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0037] In addition, the description of "first", "second" and the like in the present utility model is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection required by the present utility model.

[0038] The existing skin tenderizer generally adopts the mode of driving tungsten lamp through DC-DC step-down chip to perform dimming.

[0039] (1) Due to the integrated design of the chip, the power MOS tube has small volume and large on-resistance, so the power loss is large.

[0040] (2) The DC-DC step-down chip generally adopts digital potentiometer to adjust the output voltage, which is subject to the internal resistance precision error of the digital potentiometer and the power control communication response delay, and it is difficult to realize linear control, and the dimming curve is not smooth.

[0041] (3) It is difficult to realize linear control of the DC-DC step-down chip, and when the gear is switched, the resistance of the tungsten lamp is low at low temperature, which may cause a large starting current.

[0042] (4) The price of the DC-DC step-down chip is relatively high.

[0043] In summary, the mode of driving tungsten lamp through DC-DC step-down chip to perform dimming has the problems of large power consumption, non-smooth dimming curve, large current impact risk and high cost.

[0044] The utility model provides a light adjusting circuit.

[0045] Please refer to Figure 1 In the utility model one embodiment, the light adjusting circuit includes:

[0046] The power supply input end is used for inputting the power supply;

[0047] The power supply control circuit 10 is connected with the power supply input end at one end, and the other end of the power supply control circuit 10 is used for connecting the first power supply end of the lamp;

[0048] The switch circuit 20 is connected with the second power supply end of the lamp at the first end, and the second end of the switch circuit 20 is grounded, and the switch circuit 20 is used for controlling the grounding state of the lamp;

[0049] The main control circuit 30 is connected with the controlled end of the power supply control circuit 10, and the main control circuit 30 is used for controlling the power supply control circuit 10 to input / stop inputting the power supply; the main control circuit 30 is also used for outputting the PWM control signal;

[0050] The push-pull circuit 40 is connected with the main control circuit 30 at the signal input end, the signal output end of the push-pull circuit 40 is connected with the controlled end of the switch circuit 20, and the power supply end of the push-pull circuit 40 is connected with the first end of the switch circuit 20; the push-pull circuit 40 is used for controlling the conduction time of the switch circuit 20 according to the PWM control signal to adjust the average power size of the lamp.

[0051] It should be noted that the light adjusting circuit can be applied to the skin tenderizer and other beauty devices, wherein the skin tenderizer and other beauty devices include the lamp, and the lamp can be a tungsten lamp or an LED lamp, which is not limited here.

[0052] It should be noted that the main control circuit 30 can include an STM32G070RBT6 chip, which includes a memory protection unit (MPU), a high-speed embedded memory, a direct memory access unit (DMA) and an enhanced I / O and peripheral device. For example, the embodiment can include a 128KB flash program memory and a 36KB SRAM, support complex algorithm processing and data caching, ensure enough code space and runtime data storage capacity. The embodiment can also provide 2 I2C, 2 SPI / 1 I2S and 4 USARTS, a 12-bit ADC (2.5MSPS), a low-power RTC, a high-level control PWM timer, five general 16-bit timers, two basic timers, two watchdog timers and a Systick timer, so that the STM32G070RBT6 can flexibly communicate with other modules.

[0053] In the embodiment, the power supply control circuit 10 can receive the power supply from the power supply input end and transmit it to the first power supply end of the lamp. Through the power supply control circuit 10, the master control circuit 30 can control the input / stop input of the power supply, for example, when it is needed to control the lamp to emit near-infrared light to act on the skin for skin care, the input of the power supply can be controlled, and when it is needed to control the lamp to stop emitting light, the stop input of the power supply can be controlled. When the power supply is input, the master control circuit 30 can output a PWM control signal for controlling dimming, and the push-pull circuit 40 can control the on time of the switching circuit 20 according to the PWM control signal to adjust the average power size of the lamp. For example, when the PWM control signal is at a low level, the push-pull circuit 40 outputs a high-level drive signal to drive the switching circuit 20 to be on, and the switching circuit 20 controls the lamp to be grounded, at this time, the positive electrode of the lamp is connected to the power supply input end, and the negative electrode is grounded, and there is a driving current flowing through. When the PWM control signal is at a high level, the push-pull circuit 40 outputs a low-level drive signal to drive the switching circuit 20 to be off, and the switching circuit 20 controls the lamp to stop being grounded, at this time, the lamp has no driving current flowing through. In this way, the master control circuit 30 can output PWM control signals with different duty cycles to the push-pull circuit 40, and then control the on time of the switching circuit 20, so as to adjust the average power size of the lamp. Compared with the existing dimming mode through the DC-DC step-down chip, the embodiment realizes dimming through a relatively simple circuit, has low power consumption and low cost, and controls dimming through the push-pull circuit 40 and the switching circuit 20, so as to have fast response speed, smooth dimming curve and not easy to have large current impact.

[0054] In the embodiment, the power supply control circuit 10 can receive the power supply from the power supply input end and transmit it to the first power supply end of the lamp. Through the power supply control circuit 10, the master control circuit 30 can control the input / stop input of the power supply. When the power supply is input, the master control circuit 30 can output a PWM control signal for controlling dimming, and the push-pull circuit 40 can control the on time of the switching circuit 20 according to the PWM control signal, so as to control the grounding time of the second power supply end of the lamp, and adjust the average power size of the lamp. Compared with the existing dimming mode through the DC-DC step-down chip, the utility model has the advantages of fast dimming response speed, low power consumption, smooth dimming curve, not easy to have large current impact and lower cost.

[0055] Please refer to Figure 2 In the embodiment of the utility model, the push-pull circuit 40 includes a first triode Q1, a second triode Q2 and a third triode Q3.

[0056] The base of the first triode Q1 is the signal input end of the push-pull circuit 40, the emitter of the first triode Q1 is grounded, the collector of the first triode Q1, the collector of the second triode Q2, the base of the second triode Q2, the base of the third triode Q3 are connected with the first power supply end of the lamp, the emitter of the second triode Q2 and the emitter of the third triode Q3 are connected with the controlled end of the switch circuit 20, and the collector of the third triode Q3 is grounded.

[0057] In the embodiment, the first triode Q1 and the second triode Q2 can be NPN triodes, and the third triode Q3 can be a PNP triode, the conduction and the cut-off of the second triode Q2 and the third triode Q3 are controlled through the first triode Q1, and the amplification of the output signal can be realized. In the embodiment, when the PWM control signal output by the main control circuit 30 is low, the first triode Q1 is turned on, the second triode Q2 is cut off, the third triode Q3 is turned on, and a high level is output to the switch circuit 20, at this time, the switch circuit 20 is turned on, and the lamp has current passing through. When the PWM control signal output by the main control circuit 30 is high, the first triode Q1 is cut off, the second triode Q2 is turned on, the third triode Q3 is cut off, and a low level is output to the switch circuit 20, at this time, the switch circuit 20 is turned off, and the lamp has no current passing through. In this way, the action of the switch circuit 20 can be controlled through the circuit composed of the first triode Q1, the second triode Q2 and the third triode Q3.

[0058] Please refer to Figure 2 In an embodiment of the utility model, the push-pull circuit 40 further includes a first resistor R1, a second resistor R2 and a first diode D1.

[0059] The emitter of the second triode Q2, the emitter of the third triode Q3, the positive electrode of the first diode D1 and one end of the second resistor R2 are connected, the negative electrode of the first diode D1 and one end of the first resistor R1 are connected, the other end of the first resistor R1 and the other end of the second resistor R2 are connected with the controlled end of the switch circuit 20.

[0060] In the embodiment, the circuit composed of the first resistor R1, the second resistor R2 and the first diode D1 can limit the current protection of the output of the circuit composed of the first triode Q1, the second triode Q2 and the third triode Q3, and avoid the damage of the switching element of the switch circuit 20 in the rear stage.

[0061] Please refer to Figure 2 In an embodiment of the utility model, the switch circuit 20 includes a first MOS tube M1, the gate of the first MOS tube M1 is connected with the signal output end of the push-pull circuit 40, the drain of the first MOS tube M1 is connected with the second power supply end of the lamp, and the source of the first MOS tube M1 is grounded.

[0062] In an embodiment, the first MOS transistor M1 is a power MOS transistor.

[0063] In the embodiment, the power MOS transistor can withstand a high peak current in a short time, thereby ensuring that the lamp can quickly reach the working temperature without being damaged. The power MOS transistor has a low on-resistance, thereby reducing power consumption. The power MOS transistor has a fast switching speed, thereby helping to smooth the light curve.

[0064] Referring to Figure 2 In an embodiment of the utility model, the power supply input end includes a battery power supply input end for inputting a battery power supply and an adapter power supply input end for inputting an adapter power supply, and the power supply control circuit 10 includes:

[0065] a first power supply control circuit 11, a first end of the first power supply control circuit 11 being connected with the battery power supply input end, a second end of the first power supply control circuit 11 being connected with a first power end of the lamp, a controlled end of the first power supply control circuit 11 being connected with the master control circuit 30, and the first power supply control circuit 11 being used for inputting / stopping inputting the battery power supply according to a first power control signal output by the master control circuit 30;

[0066] a second power supply control circuit 12, a first end of the second power supply control circuit 12 being connected with the adapter power supply input end, a second end of the second power supply control circuit 12 being connected with the first power end of the lamp, and a controlled end of the second power supply control circuit 12 being connected with the master control circuit 30, and the second power supply control circuit 12 being used for inputting / stopping inputting the adapter power supply according to a second power control signal output by the master control circuit 30.

[0067] In the embodiment, when it is needed to control the lamp to emit light and the adapter is connected with a power supply and has an output, the master control circuit 30 can control the second power supply control circuit 12 to perform corresponding actions to input the adapter power supply. When it is needed to control the lamp to emit light and the adapter is not connected with a power supply and has no output, the master control circuit 30 can control the first power supply control circuit 11 to perform corresponding actions to input the battery power supply. When it is not needed to control the lamp to emit light, the master control circuit 30 can control the first power supply control circuit 11 and the second power supply control circuit 12 to perform corresponding actions to stop inputting the adapter power supply and the battery power supply. In this way, the power supply switching of the embodiment is flexible.

[0068] Referring to Figure 2In an embodiment of the present application, the first power supply control circuit 11 comprises a fourth triode Q4, a second MOS tube M2 and a third resistor R3; wherein the base of the fourth triode Q4 is the controlled end of the first power supply control circuit 11, the collector of the fourth triode Q4 and the gate of the second MOS tube M2 are connected with one end of the third resistor R3, the emitter of the fourth triode Q4 is grounded, the other end of the third resistor R3 and the drain of the second MOS tube M2 are connected with the battery power input end, and the source of the second MOS tube M2 is connected with the first power end of the lamp; and / or,

[0069] The second power supply control circuit 12 comprises a fifth triode Q5, a third MOS tube M3 and a fourth resistor R4; wherein the base of the fifth triode Q5 is the controlled end of the second power supply control circuit 12, the collector of the fifth triode Q5 and the gate of the third MOS tube M3 are connected with one end of the fourth resistor R4, the emitter of the fifth triode Q5 is grounded, the other end of the fourth resistor R4 and the drain of the third MOS tube M3 are connected with the adapter power input end, and the source of the third MOS tube M3 is connected with the first power end of the lamp.

[0070] In the embodiment, the second MOS tube M2 and the third MOS tube M3 can be PMOS tubes, which are suitable for switching of the power supply.

[0071] In the embodiment, when the first power control signal is high, the fourth triode Q4 is turned on, the second MOS tube M2 is turned on, and the battery power supply is inputted. When the second power control signal is high, the fifth triode Q5 is turned on, the third MOS tube M3 is turned on, and the adapter power supply is inputted.

[0072] Please refer to Figure 2 In an embodiment of the present application, the dimming circuit further comprises:

[0073] The voltage detection circuit 50 is connected with the second power end of the lamp at the detection end, and is connected with the main control circuit 30 at the signal output end, and is used for detecting the voltage of the second power end of the lamp and outputting the corresponding detection signal;

[0074] The main control circuit 30 is further used for determining the open circuit state of the lamp according to the detection signal.

[0075] In the embodiment, when the main control circuit 30 determines that the voltage of the second power end is abnormally low (for example, far lower than the preset working voltage range) according to the detection signal, it can be inferred that the lamp may be in an open circuit state. This may be caused by filament rupture, loose connection or other electrical faults. Once it is confirmed that the lamp is in an open circuit state, the main control circuit 30 can perform a series of operations according to the design requirements, such as stopping power supply, issuing a warning prompt, recording error logs, etc. In this way, the safety of the circuit is improved.

[0076] Please refer to Figure 2 In an embodiment of the utility model, voltage detection circuit 50 includes fifth resistance R5, sixth resistance R6, seventh resistance R7 and first capacitor C1;

[0077] One end of sixth resistance R6 is connected with the second power supply end of the lamp, the other end of sixth resistance R6, one end of fifth resistance R5 and one end of seventh resistance R7 are connected, the other end of seventh resistance R7 and one end of first capacitor C1 are connected with the signal output end of voltage detection circuit 50, the other end of fifth resistance R5 and the other end of first capacitor C1 are grounded.

[0078] In the embodiment, fifth resistance R5, sixth resistance R6, seventh resistance R7 and first capacitor C1 can divide voltage detected by the second power supply end of the lamp and filter, which can ensure that the output detection signal is more accurate. Therefore, the embodiment improves the detection accuracy.

[0079] The utility model also proposes a kind of equipment, and the equipment includes lamp and dimming circuit, and the specific structure of the dimming circuit refers to above-mentioned embodiment, since the equipment has adopted all technical solutions of above-mentioned all embodiments, it at least has all beneficial effects brought by the technical scheme of above-mentioned embodiment, and here is not repeated one by one. It needs to be explained that, the equipment can be skin tenderizer or other beauty equipment, not limited here.

[0080] The above-mentioned is only the exemplary implementation of the utility model, and not therefore limit the patent range of the utility model, all equivalent structural transformations made in the technical concept of the utility model using the utility model specification and drawing contents or directly / indirectly applied in other related technical fields are included in the patent protection range of the utility model.

Claims

1. A dimming circuit, characterized in that, include: Power supply input terminal, used to input power supply; A power supply control circuit, one end of which is connected to the power supply input terminal, and the other end of which is used to connect to the first power supply terminal for the lamp; A switching circuit, wherein the first terminal of the switching circuit is used to connect to the second power supply terminal of the lamp, the second terminal of the switching circuit is grounded, and the switching circuit is used to control the grounding state of the lamp; The main control circuit is connected to the controlled terminal of the power supply control circuit. The main control circuit is used to control the power supply control circuit to input / stop the power supply; the main control circuit is also used to output PWM control signals. A push-pull circuit is provided, wherein the signal input terminal of the push-pull circuit is connected to the main control circuit, the signal output terminal of the push-pull circuit is connected to the controlled terminal of the switching circuit, and the power supply terminal of the push-pull circuit is connected to the first terminal of the switching circuit. The push-pull circuit is used to control the conduction time of the switching circuit according to the PWM control signal to adjust the average power of the lamp.

2. The dimming circuit as described in claim 1, characterized in that, The push-pull circuit includes a first transistor, a second transistor, and a third transistor; In this circuit, the base of the first transistor is the signal input terminal of the push-pull circuit, the emitter of the first transistor is grounded, the collector of the first transistor, the collector of the second transistor, the base of the second transistor, and the base of the third transistor are connected to the first power supply terminal of the lamp, the emitters of the second transistor and the third transistor are connected to the controlled terminal of the switching circuit, and the collector of the third transistor is grounded.

3. The dimming circuit as described in claim 2, characterized in that, The push-pull circuit also includes a first resistor, a second resistor, and a first diode; The emitter of the second transistor, the emitter of the third transistor, and the anode of the first diode are connected to one end of the second resistor. The cathode of the first diode is connected to one end of the first resistor. The other ends of the first resistor and the other ends of the second resistor are connected to the controlled terminal of the switching circuit.

4. The dimming circuit as described in claim 1, characterized in that, The switching circuit includes a first MOSFET, the gate of which is connected to the signal output terminal of the push-pull circuit, the drain of which is connected to the second power supply terminal of the lamp, and the source of which is grounded.

5. The dimming circuit as described in claim 4, characterized in that, The first MOSFET is a power MOSFET.

6. The dimming circuit as described in claim 1, characterized in that, The power supply input terminal includes a battery power input terminal for inputting battery power and an adapter power input terminal for inputting adapter power. The power supply control circuit includes: A first power supply control circuit, wherein a first terminal of the first power supply control circuit is connected to the battery power input terminal, a second terminal of the first power supply control circuit is connected to the first power supply terminal of the lamp, and a controlled terminal of the first power supply control circuit is connected to the main control circuit. The first power supply control circuit is used to input / stop inputting the battery power supply according to the first power control signal output by the main control circuit. The second power supply control circuit has a first terminal connected to the power input terminal of the adapter, a second terminal connected to the first power supply terminal of the lamp, and a controlled terminal connected to the main control circuit. The second power supply control circuit is used to input / stop the power supply to the adapter according to the second power control signal output by the main control circuit.

7. The dimming circuit as described in claim 6, characterized in that, The first power supply control circuit includes a fourth transistor, a second MOSFET, and a third resistor; wherein the base of the fourth transistor is the controlled terminal of the first power supply control circuit, the collector of the fourth transistor, the gate of the second MOSFET, and one end of the third resistor are connected, the emitter of the fourth transistor is grounded, the other end of the third resistor and the drain of the second MOSFET are connected to the battery power input terminal, and the source of the second MOSFET is connected to the first power supply terminal of the lamp; and / or, The second power supply control circuit includes a fifth transistor, a third MOSFET, and a fourth resistor; wherein, the base of the fifth transistor is the controlled terminal of the second power supply control circuit, the collector of the fifth transistor, the gate of the third MOSFET, and one end of the fourth resistor are connected, the emitter of the fifth transistor is grounded, the other end of the fourth resistor and the drain of the third MOSFET are connected to the power input terminal of the adapter, and the source of the third MOSFET is connected to the first power supply terminal of the lamp.

8. The dimming circuit as described in claim 1, characterized in that, Also includes: A voltage detection circuit is provided, wherein the detection terminal of the voltage detection circuit is connected to the second power supply terminal of the lamp, and the signal output terminal of the voltage detection circuit is connected to the main control circuit. The voltage detection circuit is used to detect the voltage of the second power supply terminal of the lamp and output a corresponding detection signal. The main control circuit is also used to determine the open-circuit state of the lamp based on the detection signal.

9. The dimming circuit as described in claim 8, characterized in that, The voltage detection circuit includes a fifth resistor, a sixth resistor, a seventh resistor, and a first capacitor; Wherein, one end of the sixth resistor is connected to the second power supply terminal of the lamp, the other end of the sixth resistor and one end of the fifth resistor are connected to one end of the seventh resistor, the other end of the seventh resistor and one end of the first capacitor are connected to the signal output terminal of the voltage detection circuit, and the other end of the fifth resistor and the other end of the first capacitor are grounded.

10. A device, characterized in that, Includes a lamp and a dimming circuit as described in any one of claims 1 to 9.

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