A dimming circuit

Abstract

This application relates to a dimming circuit, which at least includes a control unit, a first dimming unit, a second dimming unit, and a power supply unit. The power supply unit is respectively connected to the control unit, the first dimming unit, and the second dimming unit. The control unit includes a control chip, and the control chip is provided with a first dimming output terminal connected to the first dimming unit and a second dimming unit connected to the second dimming unit. The first dimming unit and the second dimming unit adjust the brightness and color temperature through the signals of the control chip. The beneficial effect is that: in this application, the control chip outputs dimming signals to the first dimming unit and the second dimming unit, realizing the adjustment of the brightness and color temperature of the circuit.

Description

Technical Field

[0001] This application relates to the field of lighting technologies, and particularly to a dimming circuit. Background Art

[0002] With the rapid development of LED technologies, LED lighting fixtures have been widely used in various lighting applications. The excellent characteristics of LED light sources, such as high reliability, high efficiency, and pollution-free, have made LED lighting fixtures the mainstream in the market and an ideal light source to replace incandescent lamps or halogen lamps. However, in the comparison of dimming performance tests, it is found that there are significant differences in dimming and color adjustment between LED lighting fixtures and ordinary incandescent lighting fixtures. For LED lighting fixtures, while the luminous flux gradually decreases, its color temperature only changes slightly, which is likely to cause a decrease in lighting comfort when used in home lighting and specific lighting occasions. Summary of the Invention

[0003] To solve the above technical problems, this application provides a dimming circuit, which at least includes a control unit, a first dimming unit, a second dimming unit, and a power supply unit. The power supply unit is respectively connected to the control unit, the first dimming unit, and the second dimming unit.

[0004] The control unit includes a control chip, and the control chip is provided with a first dimming output terminal connected to the first dimming unit and a second dimming output terminal connected to the second dimming unit. The first dimming unit and the second dimming unit adjust the brightness and color temperature through the signals of the control chip.

[0005] Optionally, the control unit is at least further provided with a first filter circuit, a clock circuit, and an infrared input circuit.

[0006] The first filter circuit includes at least one filter capacitor connected to the control chip.

[0007] The clock circuit includes a clock crystal oscillator connected to the control chip, and filter capacitors are also connected to both ends of the clock crystal oscillator.

[0008] The infrared input circuit includes an infrared receiver. The power supply terminal of the infrared receiver is connected to a second power supply, and the output terminal of the infrared receiver is respectively connected to the second power supply and the infrared receiving terminal of the control chip.

[0009] Optionally, the power supply unit includes a first power supply circuit and a second power supply circuit.

[0010] The first power supply circuit includes a rectification circuit, a first power supply chip, and a second filtering circuit. The input end of the rectification circuit is connected to external alternating current, the output end of the rectification circuit is connected to the first power supply chip, and the first power supply chip outputs a first power supply through the second filtering circuit. The rectification circuit and the external alternating current are also connected with a first switch;

[0011] The second power supply circuit includes a second power supply chip and a third filtering circuit. The input end of the second power supply chip is connected to the first power supply, and the output end of the second power supply chip outputs a second power supply through the third filtering circuit.

[0012] Optionally, the power supply unit includes a first detection circuit, and the first detection circuit includes a first triode. The base of the first triode is connected to the input end of the first power supply chip through a first resistor and a first diode. The collector is connected to the first detection end of the control chip and the second power supply, and the emitter is grounded.

[0013] Optionally, the first dimming unit includes a first dimming chip and a switch circuit. The first dimming chip is provided with a first input end connected to the first dimming output end, a first control end for controlling the on / off of the switch circuit, a first feedback end for receiving the feedback signal of the switch circuit, and a first power supply input end. The first power supply outputs a third power supply through at least one resistor, and the first power supply input end is connected to the third power supply.

[0014] Optionally, the switch circuit includes a second MOS tube and an induction coil;

[0015] The gate of the second MOS tube is connected to the first control end, the source is connected to the first coil of the induction coil, and the drain is connected to the first feedback end and grounded through at least one resistor;

[0016] One end of the first coil of the induction coil connected to the second MOS tube is connected to the first power supply through a second diode and a third diode connected in parallel. The other end of the first coil of the induction coil is connected to the switch end of the second dimming unit. One end of the second coil of the induction coil is connected to the third power supply through a fourth diode and a third resistor;

[0017] The switch end is also connected to the first power supply through a first capacitor, a second capacitor, and a second resistor connected in parallel.

[0018] Optionally, the second dimming unit includes a second dimming chip and an LED circuit. The second dimming chip is provided with a second input terminal connected to the second dimming output terminal of the control chip, a first output terminal and a second output terminal connected to the LED circuit, and a second power input terminal connected to a third power supply; the LED circuit is provided with a switch terminal connected to the first dimming unit; the LED circuit is controlled by the first dimming unit and the second dimming chip.

[0019] Optionally, the LED circuit includes a third MOS transistor, a fourth MOS transistor, a first LED lamp, a second LED lamp, a third capacitor, and a fourth capacitor; the gate of the third MOS transistor is connected to the first output terminal, and the drain is connected to the first power supply through the first LED lamp and the third capacitor connected in parallel; the gate of the fourth MOS transistor is connected to the second output terminal, and the drain is connected to the first power supply through the second LED lamp and the fourth capacitor connected in parallel; the sources of the third MOS transistor and the fourth MOS transistor are the switch terminals of the second dimming unit and are connected to the first unit.

[0020] Optionally, the first LED lamp is a warm-color lamp, and the second LED lamp is a cold-color lamp.

[0021] Optionally, a third dimming unit is further included. The third dimming unit includes a second triode and a third LED lamp. The base of the second triode is connected to the third dimming output terminal of the control chip through a fourth resistor, the collector is connected to the third LED lamp through a fifth resistor, and the emitter is grounded; the other end of the third LED lamp is connected to the second power supply.

[0022] The beneficial effects of a dimming circuit of the present application are as follows:

[0023] (1) In the present application, the control chip outputs dimming signals to the first dimming unit and the second dimming unit to realize the adjustment of the brightness and color temperature of the circuit.

[0024] (2) In the present application, an infrared receiver is arranged on the control chip to receive infrared signals, and the infrared signals are converted into controls by the control chip for circuit control to realize wireless control; meanwhile, a filtering circuit and a clock circuit are arranged on the control chip to stabilize the circuit and provide clock signals.

[0025] (3) In the present application, a first power supply circuit and a second power supply circuit are arranged to output different power supplies respectively to meet the normal operation of each component of the circuit; meanwhile, a first detection circuit is arranged in the first power supply circuit to output detection signals to the control chip for power supply detection.

[0026] (4) In this application, a switch circuit is provided in the first dimming unit, and it receives the signal from the control chip. The on-off time of the LED lights in the second dimming unit is controlled through the switch circuit to adjust the brightness and power of the LED lights. At the same time, multiple circuit elements of the protection circuit are provided in the switch circuit to protect the circuit.

[0027] (5) In this application, an LED circuit is provided in the second dimming unit, and the on-off of two paths of LED lights is controlled respectively through the first output terminal and the second output terminal of the second dimming chip for color temperature control.

[0028] (6) This application also provides a third dimming unit, and the control chip controls the on-off of the third LED light for circuit switch indication or night indication. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the dimming circuit according to the embodiment of this application.

[0030] Figure 2 It is a schematic diagram of the control chip according to the embodiment of this application.

[0031] Figure 3 It is a circuit diagram of the infrared input circuit according to the embodiment of this application.

[0032] Figure 4 It is a circuit diagram of the first power supply circuit according to the embodiment of this application.

[0033] Figure 5 It is a circuit diagram of the second power supply circuit according to the embodiment of this application.

[0034] Figure 6 It is a circuit diagram of the first dimming unit according to the embodiment of this application.

[0035] Figure 7 It is a circuit diagram of the second dimming unit according to the embodiment of this application.

[0036] Figure 8 It is a circuit diagram of the third dimming unit according to the embodiment of this application. Detailed Embodiment

[0037] The following elaborates on the preferred embodiments of this application in conjunction with the drawings, so that the advantages and features of this application can be more easily understood by those skilled in the art, thereby making the protection scope of this application more clearly defined.

[0038] In Figure 1-2In the illustrated embodiment, the present application provides a dimming circuit, which at least includes a control unit 100, a first dimming unit 200, a second dimming unit 300, and a power supply unit 500. The power supply unit 500 is respectively connected to the control unit 100, the first dimming unit 200, and the second dimming unit 300. The control unit 100 includes a control chip U1, and the control chip U1 is provided with a first dimming output terminal PWM1 connected to the first dimming unit 200 and a second dimming output terminal PWM2 connected to the second dimming unit 300. The first dimming unit 200 and the second dimming unit 300 adjust the brightness and color temperature through the signals of the control chip U1. In this embodiment, the control chip U1 is used to output signals to the first dimming unit 200. The first dimming unit 200 is used to adjust the power and brightness of the LED lamp. The second dimming unit 300 is used to adjust the color temperature of the LED lamp. The power supply unit 500 is used to supply power to each device in the circuit. The present application outputs dimming signals to the first dimming unit 200 and the second dimming unit 300 through the control chip U1 to achieve the adjustment of the brightness and color temperature of the circuit.

[0039] In an implementation manner of the above embodiment, the control unit 100 is at least further provided with a first filter circuit, a clock circuit, and an infrared input circuit. The first filter circuit includes at least one filter capacitor connected to the control chip U1. The first filter circuit filters the clutter in the control chip U1 to stabilize the circuit. The clock circuit includes a clock crystal oscillator Y1 connected to the control chip U1, and filter capacitors are also connected to both ends of the clock crystal oscillator Y1. The control circuit provides a clock source through the clock crystal oscillator Y1 to ensure the normal operation of the circuit. The filter capacitor connected to the clock crystal oscillator Y1 plays a role in filtering clutter to ensure signal stability. The infrared input circuit includes an infrared receiver X1. The power supply terminal of the infrared receiver X1 is connected to the second power supply VDD2. The output terminal of the infrared receiver X1 is respectively connected to the second power supply VDD2 and the infrared receiving terminal REC of the control chip U1. Resistors and / or capacitors are also connected to the power supply terminal and the output terminal of the infrared receiver X1 to protect the circuit. The control chip U1 is provided with the infrared receiver X1 to receive infrared signals, and the infrared signals are converted into controls through the control chip U1 for circuit control to achieve wireless control. See Figure 3 . Among them, the control chip U1 can be a chip with the model STM8S003F3P6.

[0040] In the Figure 4-5 illustrated embodiment, the power supply unit 500 includes a first power supply circuit and a second power supply circuit;

[0041] The first power supply circuit includes a rectification circuit 510, a first power supply chip U2, and a second filtering circuit 520. The input end of the rectification circuit 510 is connected to an external alternating current, and the output end of the rectification circuit 510 is connected to the first power supply chip U2. And the first power supply chip U2 outputs a first power supply VDD1 through the second filtering circuit 520. In this embodiment, the rectification circuit 510 includes at least one resistor, at least one induction coil, at least one capacitor, and a current limiting protection tube. The rectification circuit 510 is connected across the alternating current, performs rectification and voltage regulation, and outputs the external voltage to the first power supply chip U2. The first power supply chip U2 can be a chip for converting alternating current to direct current with the model GBU406. The first power supply circuit converts the external alternating current to direct current through the first power supply chip U2 and outputs it through the second filtering circuit 520. The second filtering circuit 520 includes at least one capacitor, resistor, and inductor, performs voltage regulation and filtering, and outputs the first power supply VDD1. The rectification circuit is also connected to the external alternating current with a first switch S1. This application controls the on / off of the circuit through the first switch S1.

[0042] The second power supply circuit includes a second power supply chip U3 and a third filtering circuit 540. The input end of the second power supply chip U3 is connected to the first power supply VDD1, and the output end of the second power supply chip U3 outputs a second power supply VDD2 through the third filtering circuit 540. In this embodiment, the second power supply chip U3 can be a power supply chip with the signal BP2525. The second power supply chip U3 converts the first power supply VDD1 into a second power supply VDD2 for other components such as the control chip U1 to work. The second power supply VDD2 is rectified and filtered through the third filtering circuit 540 for output. The third filtering circuit 540 includes at least one capacitor, resistor, inductor, and diode connected to the second power supply chip U3. The second power supply circuit performs rectification and filtering through the third filtering circuit 540.

[0043] This application outputs different power supplies by setting the first power supply circuit and the second power supply circuit to meet the normal operation of each component of the circuit.

[0044] In one of the above embodiments, the power supply unit 500 includes a first detection circuit 530, and the first detection circuit 530 includes a first triode Q1; the base of the first triode Q1 is connected to the input end of the first power supply chip U2 through a first resistor R1 and a first diode D1, the collector is connected to the first detection end SWITCH of the control chip U1 and the second power supply VDD2, and the emitter is grounded. In this embodiment, a resistor is connected between the collector of the first triode Q1 and the second power supply VDD2, and the base of the first triode Q1 is grounded through a resistor to protect the circuit by setting resistor voltage division. The first detection circuit 530 can be set at any input end of the first power supply chip U2. When the first power supply chip U2 is connected to external alternating current, the external alternating current passes through the first diode D1 and the first electrode, causing the first triode Q1 to conduct, grounding the first detection end of the control chip U1, that is, the first detection end is a low-level signal; otherwise, the first triode Q1 is cut off, and the first detection end is connected to the second power supply VDD2, that is, the first detection end is a high level. The first detection circuit 530 outputs the detection signal to the control chip U1 for power supply detection.

[0045] In addition, the first detection circuit of the present application can also detect whether the first switch is turned on. After the switch is turned off, the first detection end SWITCH is connected to the second power supply, and the level input to the control chip is a high level; after the switch is closed, the first detection end SWITCH has a periodic level change signal; by detecting the signal of the first detection end SWITCH, the function of the switch switching mode is increased, and at the same time, it is checked that all outputs are turned off once the power supply is disconnected to protect the subsequent circuit; and by detecting the period of the first detection end SWITCH, the stability of the power supply is monitored. Once the period exceeds the period of the alternating current, all outputs are turned off to protect the subsequent circuit.

[0046] In Figure 6In the illustrated embodiment, the first dimming unit 200 includes a first dimming chip U4 and a switching circuit 210. The first dimming chip U4 is provided with a first input terminal U4_PWM connected to the first dimming output terminal PWM1, a first control terminal U4_GATE for controlling the on / off of the switching circuit 210, a first feedback terminal U4_SW for receiving the feedback signal of the switching circuit 210, and a first power input terminal U4_VCC; the first power supply VDD1 outputs a third power supply VDD3 through at least one resistor, and the first power input terminal U4_VCC is connected to the third power supply VDD3. In this embodiment, the first dimming chip U4 controls the on / off of the LED lamp of the second dimming unit 300 through the switching circuit 210 by receiving a signal from the control chip U1, thereby adjusting the power of the LED lamp. Among them, the third power supply VDD3 is generated by the first power supply VDD1 being divided by at least one resistor, and the third power supply VDD3 is used to supply power to the first dimming chip U4 and the second dimming chip U5. The first dimming chip U4 can be a chip with a signal of BP2878. At least one resistor and capacitor are also connected between the first input terminal U4_PWM of the first dimming chip U4 and the control chip U1 for filtering, voltage division, and protecting the circuit.

[0047] In an implementation manner of the above embodiment, the switching circuit 210 includes a second MOS transistor Q2 and an induction coil L1;

[0048] The gate of the second MOS transistor Q2 is connected to the first control terminal U4_GATE, the source is connected to the first coil of the induction coil L1, and the drain is connected to the first feedback terminal U4_SW and grounded through at least one resistor;

[0049] One end of the first coil of the induction coil L1 connected to the second MOS transistor Q2 is connected to the first power supply VDD1 through the second diode D2 and the third diode D3 connected in parallel; the other end of the first coil of the induction coil L1 is connected to the switch terminal of the second dimming unit 300; one end of the second coil of the induction coil L1 is connected to the third power supply VDD3 through the fourth diode D4 and the third resistor R3;

[0050] The switch terminal is also connected to the first power supply VDD1 through the first capacitor C1, the second capacitor C2, and the second resistor R2 connected in parallel.

[0051] In this embodiment, the switch terminal of the second dimming unit 300 is connected to one end of the first coil of the induction coil L1, and the other end of the first coil is connected to the drain of the second MOS transistor Q2. The first dimming chip U4 continuously outputs a level signal through the first control terminal U4_GATE according to the first PWM signal received from the first PWM output terminal PWM1 of the control chip U1 to control the on and off of the second MOS transistor Q2. At least one resistor and a diode are also arranged between the first control terminal U4_GATE and the second MOS transistor Q2 to form a voltage dividing protection circuit. When the first control terminal U4_GATE outputs a high level, the second MOS transistor Q2 is turned on, and the switch terminal of the second dimming unit 300 is grounded through a resistor connected to the source of the second MOS transistor Q2; the LED lamp of the second dimming unit 300 is lit. When the first control terminal U4_GATE outputs a low level, the second MOS transistor Q2 is turned off, and the switch terminal LED_GND of the second dimming unit 300 is connected to the first power supply VDD1 through the first capacitor C1, the second capacitor C2, and the second resistor R2 connected in parallel, that is, the switch terminal LED_GND of the second dimming unit 300 is at a high level, and the LED lamp of the second dimming unit 300 is turned off. Among them, the first capacitor C1 and the second capacitor C2 play a filtering role, and the second resistor R2 plays a discharging role. The first dimming chip U4 also detects whether there is current passing through the source of the second MOS transistor Q2 through the first feedback terminal U4_SW to feedback whether the current switch is turned on.

[0052] Since the second MOS transistor Q2 is controlled by the first PWM output by the control chip U1 to conduct and cut off at a high frequency; when the second MOS transistor Q2 is cut off, the electric quantity at the drain of the second MOS transistor Q2 is greater than the electric quantity of the first power supply VDD1, and the electric quantity at the drain of the second MOS transistor Q2 is diverted to the first power supply VDD1 through the second diode D2 and the third diode D3. At the same time, the voltage generated by the second coil of the induction coil L1 is diverted and voltage-divided through the fourth diode D4 and the third resistor R3. When the voltage at the output terminal of the third resistor R3 is greater than the third voltage, the voltage of the third resistor R3 flows to the third power supply VDD3. In this application, the second diode D2, the third diode D3, the fourth diode D4, and the third resistor R3 are provided to form a protection circuit to avoid excessive voltage.

[0053] In this application, a switch circuit 210 is provided in the first dimming unit 200, and the signal transmitted from the control chip U1 is received. The on and off time of the LED lamp of the second dimming unit 300 is controlled through the switch circuit 210 to adjust the power and brightness of the LED lamp; at the same time, a plurality of circuit elements of the protection circuit are provided in the switch circuit 210 to protect the circuit.

[0054] In Figure 7In the illustrated embodiment, the second dimming unit 300 includes a second dimming chip U5 and an LED circuit. The second dimming chip U5 is provided with a second input terminal U5_PWM connected to the second dimming output terminal PWM2 of the control chip U1, a first output terminal U5_OUT1 connected to the LED circuit, a second output terminal U5_OUT1, and a second power input terminal U5_VCC connected to the third power supply VDD3; the LED circuit is provided with a switch terminal LED_GND connected to the first dimming unit 200; the LED circuit is controlled by the first dimming unit 200 and the second dimming chip U5. Among them, a resistor and a capacitor are also connected between the second input terminal U5_PWM and the control chip U1 for protecting the circuit.

[0055] In the above embodiment, the LED circuit includes a third MOS transistor Q3, a fourth MOS transistor Q4, a first LED lamp LED1, a second LED lamp LED2, a third capacitor C3, and a fourth capacitor C4; the gate of the third MOS transistor Q3 is connected to the first output terminal U5_OUT1, and the drain is connected to the first power supply VDD1 through the mutually parallel first LED lamp LED1 and third capacitor C3; the gate of the fourth MOS transistor Q4 is connected to the second output terminal U5_OUT1, and the drain is connected to the first power supply VDD1 through the mutually parallel second LED lamp LED2 and fourth capacitor C4; the sources of the third MOS transistor Q3 and the fourth MOS transistor Q4 are the switch terminal LED_GND of the second dimming unit 300 and are connected to the first unit. In this embodiment, the second dimming chip U5 outputs level signals through the first output terminal U5_OUT1 and the second output terminal U5_OUT1 to control the on and off of the first LED lamp LED1 and the second LED lamp LED2. The first LED lamp LED1 can be a warm-color lamp, and the second LED lamp LED2 can be a cold-color lamp. Among them, the second dimming chip U5 can be a dimming chip of model BP5919. By receiving the second PWM signal from the control chip U1, two signals are respectively output. Among them, the level signals output by the first output terminal U5_OUT1 and the second output terminal U5_OUT1 are complementary signals. The third capacitor C3 and the fourth capacitor C4 play a buffering role in this circuit to prevent damage to the LED lamp during high-frequency on and off of the circuit.

[0056] When the switching circuit 210 of the first dimming unit 200 is turned on, when the first output terminal U5_OUT1 outputs a high-level signal and the second output terminal U5_OUT1 outputs a low-level signal, the third MOS transistor Q3 is turned on and the fourth MOS transistor Q4 is turned off, and the first LED lamp LED1 is lit and the second LED lamp LED2 is extinguished. When the first output terminal U5_OUT1 outputs a low-level signal and the second output terminal U5_OUT1 outputs a high-level signal, the fourth MOS transistor Q4 is turned on and the third MOS transistor Q3 is turned off, and the second LED lamp LED2 is lit and the first LED lamp LED1 is extinguished. In this application, the adjustment of cold or warm light can be performed by controlling one of the LED lamps to be lit. In this application, the color temperature can also be controlled by controlling the lighting duration of the first LED lamp LED1 and the second LED lamp LED2 respectively. When the switching circuit 210 of the first dimming unit 200 is not turned on, the first LED lamp LED1 and the second LED lamp LED2 are not lit.

[0057] In the embodiment as Figure 8 shown, a third dimming unit 400 is further included. The third dimming unit 400 includes a second triode Q5 and a third LED lamp LED3. The base of the second triode Q5 is connected to the third dimming output terminal PWM3 of the control chip U1 through a fourth resistor R4, the collector is connected to the third LED lamp LED3 through a fifth resistor R5, and the emitter is grounded; the other end of the third LED lamp LED3 is connected to the second power supply VDD2. The third dimming unit 400 controls the on / off of the second triode Q5 by receiving the third PWM signal transmitted from the control chip U1, and further controls the on / off of the third LED lamp LED3. When the third PWM signal is at a high level, the second triode Q5 is turned on and the third LED lamp LED3 is lit. In this application, a third dimming unit 400 is also provided, and the control chip U1 controls the lighting and extinguishing of the third LED lamp LED3 for circuit switch indication or night indication.

[0058] The embodiments of the present application have been described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present application within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A dimming circuit, characterized in that, It includes at least a control unit, a first dimming unit, a second dimming unit, and a power supply unit. The power supply unit is respectively connected to the control unit, the first dimming unit, and the second dimming unit; The control unit includes a control chip, and the control chip is provided with a first dimming output terminal connected to the first dimming unit and a second dimming output terminal connected to the second dimming unit; the first dimming unit and the second dimming unit adjust brightness and color temperature through the signals of the control chip; The power supply unit includes a first power supply circuit and a second power supply circuit; The first power supply circuit includes a rectification circuit, a first power supply chip, and a second filtering circuit. The input end of the rectification circuit is connected to external alternating current, the output end of the rectification circuit is connected to the first power supply chip, and the first power supply chip outputs a first power supply through the second filtering circuit. The rectification circuit is also connected to the external alternating current with a first switch; the second power supply circuit includes a second power supply chip and a third filtering circuit. The input end of the second power supply chip is connected to the first power supply, and the output end of the second power supply chip outputs a second power supply through the third filtering circuit; The first dimming unit includes a first dimming chip and a switching circuit. The first dimming chip is provided with a first input terminal connected to the first dimming output terminal, a first control terminal for controlling the on / off of the switching circuit, a first feedback terminal for receiving the feedback signal of the switching circuit, and a first power supply input terminal; the first power supply outputs a third power supply through at least one resistor, and the first power supply input terminal is connected to the third power supply; The switching circuit includes a second MOS transistor and an induction coil; the gate of the second MOS transistor is connected to the first control terminal, the source is connected to the first coil of the induction coil, the drain is connected to the first feedback terminal and grounded through at least one resistor; one end of the first coil of the induction coil connected to the second MOS transistor is connected to the first power supply through a second diode and a third diode connected in parallel; the other end of the first coil of the induction coil is connected to the switching end of the second dimming unit; one end of the second coil of the induction coil is connected to the third power supply through a fourth diode and a third resistor; the switching end is also connected to the first power supply through a first capacitor, a second capacitor, and a second resistor connected in parallel; The control unit is at least further provided with a first filtering circuit, a clock circuit, and an infrared input circuit; The first filtering circuit includes at least one filtering capacitor connected to the control chip; the clock circuit includes a clock crystal oscillator connected to the control chip, and filtering capacitors are also connected to both ends of the clock crystal oscillator; the infrared input circuit includes an infrared receiver. The power supply end of the infrared receiver is connected to the second power supply, and the output end of the infrared receiver is respectively connected to the second power supply and the infrared receiving end of the control chip.

2. The dimming circuit according to claim 1, characterized in that, The power supply unit includes a first detection circuit, and the first detection circuit includes a first triode; the base of the first triode is connected to the input end of the first power supply chip through a first resistor and a first diode, the collector is connected to the first detection end of the control chip and a second power supply, and the emitter is grounded.

3. The dimming circuit according to claim 1, characterized in that, The second dimming unit includes a second dimming chip and an LED circuit. The second dimming chip is provided with a second input end connected to the second dimming output end of the control chip, a first output end and a second output end connected to the LED circuit, and a second power input end connected to a third power supply; the LED circuit is provided with a switch end connected to the first dimming unit; the LED circuit is controlled by the first dimming unit and the second dimming chip.

4. The dimming circuit according to claim 3, characterized in that, The LED circuit includes a third MOS transistor, a fourth MOS transistor, a first LED lamp, a second LED lamp, a third capacitor, and a fourth capacitor; the gate of the third MOS transistor is connected to the first output end, and the drain is connected to the first power supply through the first LED lamp and the third capacitor connected in parallel; the gate of the fourth MOS transistor is connected to the second output end, and the drain is connected to the first power supply through the second LED lamp and the fourth capacitor connected in parallel; the sources of the third MOS transistor and the fourth MOS transistor are the switch end of the second dimming unit and are connected to the first unit.

5. The dimming circuit according to claim 4, characterized in that, The first LED lamp is a warm-color lamp, and the second LED lamp is a cold-color lamp.

6. The dimming circuit according to claim 1, characterized in that, It further includes a third dimming unit. The third dimming unit includes a second triode and a third LED lamp. The base of the second triode is connected to the third dimming output end of the control chip through a fourth resistor, the collector is connected to the third LED lamp through a fifth resistor, and the emitter is grounded; the other end of the third LED lamp is connected to a second power supply.

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