Control circuit of a luminaire

Abstract

This utility model discloses a lighting control circuit, including a power supply, a control unit, and a switching unit controlled by the control unit. The output terminal of the power supply is electrically connected to both the control unit and the switching unit. The switching unit includes three sets of switching circuits. Each set of switching circuits includes a first switching transistor and a second switching transistor controlled by the control unit. The first pin of the first switching transistor is connected to the output terminal of the power supply, and the third pin of the first switching transistor is connected to the first pin of the second switching transistor. The second pin of the second switching transistor is connected to the control unit, and the third pin of the second switching transistor is grounded. Each set of switching circuits also includes a third switching transistor, the first pin of which is connected to the second pin of the first switching transistor, and the second pin of the third switching transistor is connected to the control unit. The third pin of the third switching transistor is grounded. This utility model is applicable to high-voltage or low-voltage loads and has the advantage of wide applicability.

Description

Technical Field

[0001] This utility model relates to the field of lighting technology, specifically to a control circuit for a lamp. Background Technology

[0002] Figure 6 The lighting controller disclosed in CN217789939U includes a DC power supply, a control unit, and a switching unit 3 controlled by the control unit 2 to turn on or off. The output terminal of the DC power supply is electrically connected to the control unit and the switching unit. The switching unit 3 includes three sets of switching circuits. Each set of switching circuits includes a load connection part A, B, C and two first switching transistors Q3, Q2, Q1 and second switching transistors Q4, Q5, Q6 independently controlled by the control unit 2. The first pins of the first switching transistors Q3, Q2, Q1 are connected to the control unit. The output terminal of unit 2 is connected, the second pin of the first switching transistors Q3, Q2, and Q1 is used to connect to the DC power supply, the third pin of the first switching transistors Q3, Q2, and Q1 is connected to the third pin of the second switching transistors Q4, Q5, and Q6, the first pin of the second switching transistors Q4, Q5, and Q6 is connected to the output terminal of control unit 2, and the second pin of the second switching transistors Q4, Q5, and Q6 is grounded. The load connection parts A, B, and C are located at the connection points between the third pin of the first switching transistors Q3, Q2, and Q1 and the third pin of the second switching transistors Q4, Q5, and Q6.

[0003] The problem with the above circuit is that it is only suitable for low-voltage power supplies (taking one set of switching circuits as an example). The reason is that the supply voltage of microcontroller U2 is 5V, and the highest voltage output of microcontroller U2 is 5V. When V+ is 5V and pin 13 of microcontroller U2 outputs a low level to the base of the first switching transistor Q1, the first switching transistor Q1 is turned on. When pin 13 of microcontroller U2 outputs 5V to the base of the first switching transistor Q1, the collector voltage of the first switching transistor Q1 is 5V, which turns the first switching transistor Q1 off. However, when the voltage V+ is greater than 5V, such as 12V, 24V, or 31V, even if pin 13 of microcontroller U2 outputs 5V to the base of the first switching transistor Q1, a potential difference exists across Q1 due to the 12V, 24V, or 31V applied to it. Therefore, when V+ exceeds 5V, this circuit cannot turn off Q1 regardless of whether microcontroller U2 outputs a high or low level, ultimately failing to control the lamp. Thus, when the voltage required by the lamp load exceeds 5V, the above circuit is unsuitable, requiring a separate circuit to control these high-voltage lamps, which undoubtedly increases costs. Therefore, it is clear that the above circuit is not suitable for both high-voltage and low-voltage loads.

[0004] In addition, there may be inductive components in the load. Inductive components will store electrical energy. When the switching transistor is turned off, the voltage of the inductive component will be applied to the load connection. If the voltage is high, it will damage each switching transistor. If the voltage exceeds the voltage rating of the switching transistor, it will directly damage the switching transistor. Utility Model Content

[0005] This invention provides a control circuit for lamps that can be used with high-voltage or low-voltage loads.

[0006] The technical solutions to the above technical problems are as follows:

[0007] The control circuit of the lighting fixture includes a power supply, a control unit, and a switching unit controlled by the control unit. The output terminal of the power supply is electrically connected to the control unit and the switching unit. The switching unit includes three sets of switching circuits. Each set of switching circuits includes a first switching transistor and a second switching transistor controlled by the control unit. The first pin of the first switching transistor is connected to the output terminal of the power supply, the third pin of the first switching transistor is connected to the first pin of the second switching transistor, the second pin of the second switching transistor is connected to the control unit, and the third pin of the second switching transistor is grounded. Each set of switching circuits also includes a third switching transistor. The first pin of the third switching transistor is connected to the second pin of the first switching transistor, the second pin of the third switching transistor is connected to the control unit, and the third pin of the third switching transistor is grounded.

[0008] When the control unit outputs a high level to the third switch, the third switch in the first set of switching circuits is turned on. Since the emitter of the third switch is grounded, the second pin of the first switch is at a low level, while the collector of the first switch is at a high level, thus the first switch is in the on state. When the control unit outputs a low level to the third switch, the third switch is not turned on. At this time, there is no voltage difference between the first and second pins of the first switch, thus the first switch is in the off state. Therefore, regardless of whether the output voltage of the power supply is low or high, this invention can control the first switch to turn on or off. The control unit alternately turns the first and second switches on or off, thereby causing the lamp connected to the output terminal to produce the corresponding lighting effect. This invention, by adding a third switch, eliminates the need for a control chip to control the thyristor to achieve high voltage control of the switching unit, as in the prior art. Therefore, this invention has the advantages of simple structure and low cost compared to the prior art. Attached Figure Description

[0009] Figure 1 This is a circuit diagram of the control circuit of the lamp of this utility model.

[0010] Figure 2 for Figure 1 The schematic diagram of the control unit in the system.

[0011] Figure 3 for Figure 1 The schematic diagram of the switching unit in the diagram.

[0012] Figure 4 This is a circuit diagram for the first type of lamp connected to the output of the switching unit.

[0013] Figure 5 This is a circuit diagram for a second type of lamp connected to the output of the switching unit.

[0014] Figure 6 This is a circuit diagram of a control unit and a switching unit in the prior art. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0016] like Figures 1 to 3 As shown, the control circuit of the lamp of this utility model includes a power supply 1, a control unit 2, and a switching unit 3 controlled by the control unit 2. The output terminal VIN of the power supply 1 is electrically connected to the control unit 2 and the switching unit 3 respectively. The power supply 1 is a power supply that outputs DC power. The power supply 1 adopts a conventional power supply circuit, the structure of which will not be described in detail here. The voltage output by the output terminal VIN of the power supply 1 in this utility model is 5-31V, for example, it can be any one of 5V, 12V, 24V, and 31V. Therefore, the control unit 2 and the switching unit 3 of this utility model can be used for both low and high input voltages.

[0017] Control unit 2 includes a twelfth resistor R12, an LED2, a nineteenth resistor R19, a Zener diode ZD1, a sixth capacitor C6, a seventh capacitor C7, an infrared receiver U4, a microcontroller U5, a crystal oscillator XL1, a twelfth capacitor C12, a thirteenth capacitor C13, an eighteenth resistor R18, an indicator LED1, and a button SW1. One end of the twelfth resistor R12 is connected to the output terminal VIN of the power supply 1. The other end of the twelfth resistor R12 is connected to the anode of the LED2, the cathode of the Zener diode ZD1, one end of the sixth capacitor C6, one end of the seventh capacitor C7, the first terminal of the infrared receiver U4, and the tenth pin of the microcontroller U5. The other end of the LED2 is connected to one end of the nineteenth resistor R19. The other end of resistor R19, the anode of Zener diode ZD1, the other end of sixth capacitor C6, the other end of seventh capacitor C7, and the second terminal of infrared receiver U4 are all grounded. The third terminal of infrared receiver U4 is connected to the eighth pin of microcontroller U5. The eleventh pin of microcontroller U5 is connected to one end of crystal oscillator XL1 and one end of twelfth capacitor C12. The twelfth pin of microcontroller U5 is connected to the other end of crystal oscillator XL1 and one end of thirteenth capacitor C13. The other ends of twelfth capacitor C12 and thirteenth capacitor C13 are both grounded. The thirteenth pin of microcontroller U5 is connected to one end of eighteenth resistor R18, and the other end of eighteenth resistor R18 is grounded. The fourteenth pin of microcontroller U5 is connected to one end of button SW1, and the other end of button SW1 is grounded. Microcontroller U5 preferably uses a microcontroller. Microcontroller U5 stores a control program for controlling the lighting mode of the lamp. After receiving the user's command signal (sent via button SW1 or infrared remote control) and running the control program, microcontroller U5 outputs a control command to change the lighting mode of the lamp.

[0018] The twelfth resistor R12 in control unit 2 is a current-limiting resistor used to reduce current. LED2 indicates that control unit 2 has received voltage from power supply 1, and Zener diode ZD1 stabilizes the voltage supplied by power supply 1 to microcontroller U5. Sixth capacitor C6 and seventh capacitor C7 filter the voltage. Infrared receiver U4 receives the infrared signal emitted by the user's infrared remote control and transmits it to microcontroller U5. Microcontroller U5 calculates the signal and outputs corresponding control commands to change the lighting mode of the lamp. Crystal oscillator XL1, twelfth capacitor C12, and thirteenth capacitor C13 form an oscillation circuit that converts the voltage into a corresponding frequency signal, which is then sent to microcontroller U5. Eighteenth resistor R18 limits the current of the electrical signal output by microcontroller U5. When indicator LED1 illuminates, it indicates that microcontroller U5 has successfully powered on. The user sends control commands to microcontroller U5 via button SW1 to change the lighting mode of the lamp.

[0019] The switching unit 3 includes three sets of switching circuits. Each set of switching circuits includes a first switching transistor Q1, Q2, Q3, a second switching transistor Q4, Q5, Q6, and a third switching transistor Q7, Q8, Q9, all controlled by the control unit 2. The first switching transistor Q1, Q2, Q3, the second switching transistor Q4, Q5, Q6, and the third switching transistor Q7, Q8, Q9 are either transistors or MOSFETs. In this embodiment, transistors are preferred.

[0020] The first pin of the first switching transistor Q1 in the first group of switching circuits is connected to the output terminal VIN of the power supply 1. The third pin of the first switching transistor Q1 in the first group of switching circuits is connected to the first pin of the second switching transistor Q4 in the first group of switching circuits. The second pin of the second switching transistor Q4 in the first group of switching circuits is connected to the ninth pin of the microcontroller U5 in the control unit 2. The third pin of the second switching transistor Q4 in the first group of switching circuits is grounded. The first pin of the third switching transistor Q7 in the first group of switching circuits is connected to the second pin of the first switching transistor Q1 in the first group of switching circuits. The second pin of the third switching transistor Q7 in the first group of switching circuits is connected to the first pin of the microcontroller U5 in the control unit 2. The third pin of the third switching transistor Q7 in the first group of switching circuits is grounded.

[0021] In the second set of switching circuits, the first pin of the first switching transistor Q2 is connected to the output terminal VIN of the power supply 1. The third pin of the first switching transistor Q2 is connected to the first pin of the second switching transistor Q5. The second pin of the second switching transistor Q5 is connected to the seventh pin of the microcontroller U5 in the control unit 2. The third pin of the second switching transistor Q5 is grounded. The first pin of the third switching transistor Q8 is connected to the second pin of the first switching transistor Q2. The second pin of the third switching transistor Q8 is connected to the second pin of the microcontroller U5 in the control unit 2. The third pin of the third switching transistor Q8 is grounded.

[0022] The first pin of the first switching transistor Q3 in the third group of switching circuits is connected to the output terminal VIN of the power supply 1. The third pin of the first switching transistor Q3 in the third group of switching circuits is connected to the first pin of the second switching transistor Q6 in the third group of switching circuits. The second pin of the second switching transistor Q6 in the third group of switching circuits is connected to the sixth pin of the microcontroller U5 in the control unit 2. The third pin of the second switching transistor Q6 in the third group of switching circuits is grounded. The first pin of the third switching transistor Q9 in the third group of switching circuits is connected to the second pin of the first switching transistor Q3 in the third group of switching circuits. The second pin of the third switching transistor Q9 in the third group of switching circuits is connected to the third pin of the microcontroller U5 in the control unit 2. The third pin of the third switching transistor Q9 in the second group of switching circuits is grounded.

[0023] Since all the aforementioned switching transistors are bipolar transistors, the first pin of each switching transistor is the collector, the second pin is the base, and the third pin is the emitter.

[0024] In this embodiment, preferably, each group of switching circuits further includes first resistors RE1, RE2, RE3, second resistors RD1, RD2, RD3, third resistors RB1, RB2, RB3, and fourth resistors RA1, RA2, RA3, wherein:

[0025] One end of the first resistor RE1 in the first group of switching circuits is connected to the output terminal VIN of the power supply 1, and the other end of the first resistor RE1 in the first group of switching circuits is connected to the second pin of the first switching transistor Q1 in the first group of switching circuits. One end of the second resistor RD1 in the first group of switching circuits is connected to the second pin of the first switching transistor Q1 in the first group of switching circuits, and the other end of the second resistor RD1 in the first group of switching circuits is connected to the first pin of the third switching transistor Q7 in the first group of switching circuits. One end of the third resistor RB1 in the first group of switching circuits is connected to the ninth pin of the microcontroller U5 in the control unit 2, and the other end of the third resistor RB1 in the first group of switching circuits is connected to the second pin of the second switching transistor Q4 in the first group of switching circuits. One end of the fourth resistor RA1 in the first group of switching circuits is connected to the first pin of the microcontroller U5 in the control unit 2, and the other end of the fourth resistor RA1 in the first group of switching circuits is connected to the second pin of the third switching transistor Q7 in the first group of switching circuits.

[0026] In the second set of switching circuits, one end of the first resistor RE2 is connected to the output terminal VIN of the power supply 1, and the other end of the first resistor RE2 is connected to the second pin of the first switching transistor Q2 in the second set of switching circuits. One end of the second resistor RD2 in the second set of switching circuits is connected to the second pin of the first switching transistor Q2 in the second set of switching circuits, and the other end of the second resistor RD2 is connected to the first pin of the third switching transistor Q8 in the second set of switching circuits. One end of the third resistor RB2 in the second set of switching circuits is connected to the seventh pin of the microcontroller U5 in the control unit 2, and the other end of the third resistor RB2 is connected to the second pin of the second switching transistor Q5 in the second set of switching circuits. One end of the fourth resistor RA2 in the second set of switching circuits is connected to the second pin of the microcontroller U5 in the control unit 2, and the other end of the fourth resistor RA2 is connected to the second pin of the third switching transistor Q8 in the second set of switching circuits.

[0027] In the third set of switching circuits, one end of the first resistor RE3 is connected to the output terminal VIN of the power supply 1, and the other end of the first resistor RE3 is connected to the second pin of the first switching transistor Q3 in the third set of switching circuits. One end of the second resistor RD3 in the third set of switching circuits is connected to the second pin of the first switching transistor Q3 in the third set of switching circuits, and the other end of the second resistor RD3 is connected to the first pin of the third switching transistor Q9 in the third set of switching circuits. One end of the third resistor RB3 in the third set of switching circuits is connected to the sixth pin of the microcontroller U5 in the control unit 2, and the other end of the third resistor RB3 is connected to the second pin of the second switching transistor Q6 in the third set of switching circuits. One end of the fourth resistor RA3 in the third set of switching circuits is connected to the third pin of the microcontroller U5 in the control unit 2, and the other end of the fourth resistor RA3 is connected to the second pin of the third switching transistor Q9 in the third set of switching circuits.

[0028] Each set of switching circuits also includes first diodes D1, D3, and D5, second diodes D2, D4, and D6, and capacitors CR1, CR2, and CR3. The first diodes D1, D3, and D5, and the second diodes D2, D4, and D6 prevent damage to the individual switching transistors from voltage surges generated by the inductive load. This helps improve circuit stability.

[0029] In this embodiment, the anode of the first diode D1 in the first group of switching circuits is connected to the third pin of the first switching transistor Q1 in the first group of switching circuits, and the cathode of the first diode D1 in the first group of switching circuits is connected to the output terminal VIN of the power supply 1. The cathode of the second diode D2 in the first group of switching circuits is connected to the third pin of the first switching transistor Q1 in the first group of switching circuits, and the anode of the second diode D2 in the first group of switching circuits is grounded. One end of the capacitor CR1 in the first group of switching circuits is connected to the second pin of the second switching transistor Q4 in the first group of switching circuits, and the other end of the capacitor CR1 in the first group of switching circuits is grounded.

[0030] In the second set of switching circuits, the anode of the first diode D3 is connected to the third pin of the first switching transistor Q2, and the cathode of the first diode D3 is connected to the output terminal VIN of power supply 1. The cathode of the second diode D4 is connected to the third pin of the first switching transistor Q2, and the anode of the second diode D4 is grounded. One end of the capacitor CR2 in the second set of switching circuits is connected to the second pin of the second switching transistor Q5, and the other end of the capacitor CR2 is grounded.

[0031] In the third set of switching circuits, the anode of the first diode D5 is connected to the third pin of the first switching transistor Q3, and the cathode of the first diode D5 is connected to the output terminal VIN of power supply 1. The cathode of the second diode D6 is connected to the third pin of the first switching transistor Q3, and the anode of the second diode D4 is grounded. One end of the capacitor CR3 in the third set of switching circuits is connected to the second pin of the second switching transistor Q6, and the other end of the capacitor CR3 is grounded.

[0032] The first set of switching circuits has a first output terminal A, the second set of switching circuits has a second output terminal B, and the third set of switching circuits has a third output terminal C. Specifically, the first output connection terminal A is led out between the third pin of the first switching transistor Q1 and the first pin of the second switching transistor Q4 in the first set of switching circuits; the second output connection terminal B is led out between the third pin of the first switching transistor Q2 and the first pin of the second switching transistor Q5 in the second set of switching circuits; and the third output connection terminal C is led out between the third pin of the first switching transistor Q3 and the first pin of the second switching transistor Q6 in the third set of switching circuits. The first output connection terminal A, the second output connection terminal B, and the third output connection terminal C are respectively connected to… Figure 4 and Figure 5 The lamp connections are shown in the diagram.

[0033] like Figure 4 and Figure 5 The illustrated lighting fixture includes a first wire 4, a second wire 5, a third wire 6, a first LED 11, a second LED 13, a third LED 12, a fourth LED 14, a fifth LED 21, and a sixth LED 22. The first wire 4 is connected to the first output terminal A of the first group of switching circuits; the second wire 5 is connected to the second output terminal B of the second group of switching circuits; and the third wire 6 is connected to the third output terminal C of the third group of switching circuits. The anode of the first LED 11 is connected to the first wire 4, and the cathode of the first LED 11 is connected to the second wire 5; the cathode of the second LED 13 is connected to the first wire 4, and the anode of the second LED 13 is connected to the second wire 5; the cathode of the third LED 12 is connected to the second wire 5, and the anode of the third LED 12 is connected to the third wire 6; the anode of the fourth LED 14 is connected to the second wire 5, and the cathode of the fourth LED 14 is connected to the third wire 6; the anode of the fifth LED 21 is connected to the first wire 4, and the cathode of the fifth LED 21 is connected to the third wire 6. The cathode of the sixth LED 22 is connected to the first wire 4, and the anode of the sixth LED 22 is connected to the third wire 6.

[0034] like Figure 4 After the first LED light 11, the second LED light 13, the third LED light 12, the fourth LED light 14, and one or more fifth LED lights 21 are cyclically connected on the wire to form a light string, the first LED light 11, the second LED light 13, the third LED light 12, and the fourth LED light 14 are distributed at equal intervals along the light string, and one or more fifth LED lights 21 are distributed next to the first LED light 11, the second LED light 13, the third LED light 12, and the fourth LED light 14 to form a background light.

[0035] like Figure 5 After the first LED light 11, the second LED light 13, the third LED light 12, the fourth LED light 14, and one or more fifth LED lights 21 and sixth LED lights 22 are cyclically connected on the wire to form a light string, wherein the first LED light 11, the second LED light 13, the third LED light 12, and the fourth LED light 14 are equidistantly distributed along the light string, and one or more fifth LED lights 21 and sixth LED lights 22 are distributed next to the first LED light 11, the second LED light 13, the third LED light 12, and the fourth LED light 14 to form a background light. The fifth LED light 21 and the sixth LED light 22 are packaged together, or the fifth LED light 21 and the sixth LED light are two positively and negatively connected LED lights in a bicolor light.

[0036] Figure 4 and Figure 5The first LED light 11 to the fourth LED light 14 are arranged in a sequential and evenly spaced manner to display the flowing light effect of the lamp (the lighting effect is reflected when the microcontroller U5 outputs control signals with different duty cycles). Through the cooperation of the infrared receiver U4 and the infrared remote control or the operation button, instructions can be sent to the microcontroller U5 to change the light emission mode of the first LED light 11 to the fourth LED light 14, thereby making the lamp produce different lighting effects. Figure 4 The fifth LED light 21 and Figure 5 The fifth LED 21 and the sixth LED 22 are both used as background lights. The colors of the fifth LED 21 and the sixth LED 22 can be different. After the control unit 2 is powered on, the background lights are in a constant-on state. The fifth LED 21 and the sixth LED 22 can also be used as lights for a flowing water effect.

[0037] The working process is explained using the first group of switching circuits in switching unit 3 as an example:

[0038] When the first pin of microcontroller U5 outputs a high level, it turns on the third switch Q7 in the first group of switching circuits. Since the emitter of the third switch Q7 is grounded, the second pin of the first switch Q1 in the first group of switching circuits is at a low level, while the collector of the first switch Q1 is at a high level. At this time, the first switch Q1 in the first group of switching circuits is in the on state. When the first pin of microcontroller U5 outputs a low level, the third switch Q7 in the first group of switching circuits cannot be turned on, that is, the third switch Q7 in the first group of switching circuits is in the off state. At this time, there is no voltage difference between the first pin and the second pin of the first switch Q1 in the first group of switching circuits, so the first switch Q1 in the first group of switching circuits is in the off state. Therefore, regardless of whether the voltage output at the output terminal VIN of the power supply 1 is low (5V) or high (e.g., a voltage greater than 5V but less than 31V), this invention can control the first switching transistor Q1 to turn on or off. The microcontroller U5 causes the first switching transistor Q1 and the second switching transistor Q4 to alternately turn on or off, thereby causing the lamp connected to the output terminal to produce the corresponding lighting effect. This invention, by adding a third switching transistor to existing circuit technology, eliminates the need for a control chip to control the thyristor to achieve high voltage control of the switching unit 3, as in the prior art. Therefore, compared to the prior art, this invention has the advantages of simple structure and low cost.

Claims

1. A lighting control circuit, comprising a power supply (1), a control unit (2), and a switching unit (3) controlled by the control unit (2), wherein the output terminal (VIN) of the power supply (1) is electrically connected to the control unit (2) and the switching unit (3), and the switching unit (3) comprises three sets of switching circuits, each set of switching circuits comprising a first switching transistor (Q1, Q2, Q3) and a second switching transistor (Q4, Q5, Q6) controlled by the control unit (2), wherein the first pin of the first switching transistor (Q1, Q2, Q3) is connected to the output terminal (VIN) of the power supply (1), the third pin of the first switching transistor (Q1, Q2, Q3) is connected to the first pin of the second switching transistor (Q4, Q5, Q6), the second pin of the second switching transistor (Q4, Q5, Q6) is connected to the control unit (2), and the third pin of the second switching transistor (Q4, Q5, Q6) is grounded, characterized in that, Each set of switching circuits also includes a third switching transistor (Q7, Q8, Q9), the first pin of the third switching transistor (Q7, Q8, Q9) is connected to the second pin of the first switching transistor (Q1, Q2, Q3), the second pin of the third switching transistor (Q7, Q8, Q9) is connected to the control unit (2), and the third pin of the third switching transistor (Q7, Q8, Q9) is grounded.

2. The lighting control circuit according to claim 1, characterized in that, Each set of switching circuits also includes a first resistor (RE1, RE2, RE3) and a second resistor (RD1, RD2, RD3). One end of the first resistor (RE1, RE2, RE3) is connected to the output terminal (VIN) of the power supply (1), and the other end of the first resistor (RE1, RE2, RE3) is connected to the second pin of the first switching transistor (Q1, Q2, Q3). One end of the second resistor (RD1, RD2, RD3) is connected to the second pin of the first switching transistor (Q1, Q2, Q3), and the other end of the second resistor (RD1, RD2, RD3) is connected to the first pin of the third switching transistor (Q7, Q8, Q9).

3. The lighting control circuit according to claim 1 or 2, characterized in that, It also includes a third resistor (RB1, RB2, RB3) and a fourth resistor (RA1, RA2, RA3). One end of the third resistor (RB1, RB2, RB3) is connected to the output terminal of the control unit (2), and the other end of the third resistor (RB1, RB2, RB3) is connected to the second pin of the second switching transistor (Q4, Q5, Q6). One end of the fourth resistor (RA1, RA2, RA3) is connected to the output terminal of the control unit (2), and the other end of the fourth resistor (RA1, RA2, RA3) is connected to the second pin of the third switch (Q7, Q8, Q9).

4. The lighting control circuit according to claim 3, characterized in that, Each set of switching circuits also includes a first diode (D1, D3, D5) and a second diode (D2, D4, D6). The anode of the first diode (D1, D3, D5) is connected to the third pin of the first switching transistor (Q1, Q2, Q3), the cathode of the first diode (D1, D3, D5) is connected to the output terminal (VIN) of the power supply (1), the cathode of the second diode (D2, D4, D6) is connected to the third pin of the first switching transistor (Q1, Q2, Q3), and the anode of the second diode (D2, D4, D6) is grounded.

5. The lighting control circuit according to claim 3 or 4, characterized in that, Each set of switching circuits also includes capacitors (CR1, CR2, CR3). One end of capacitors (CR1, CR2, CR3) is connected to the second pin of the second switching transistor (Q4, Q5, Q6), and the other end of capacitors (CR1, CR2, CR3) is grounded.

6. The lighting control circuit according to any one of claims 1 to 5, characterized in that, It also includes lamps, which include: a first wire (4), a second wire (5), a third wire (6), a first LED lamp (11), a second LED lamp (13), a third LED lamp (12), a fourth LED lamp (14), and a fifth LED lamp (21). The first set of switching circuits has a first output terminal (A), the second set of switching circuits has a second output terminal (B), and the third set of switching circuits has a third output terminal (C). The first wire (4) is connected to the first output terminal (A) of the first set of switching circuits, the second wire (5) is connected to the second output terminal (B) of the second set of switching circuits, and the third wire (6) is connected to the third output terminal (C) of the third set of switching circuits. The positive terminal of the first LED lamp (11) is connected to the first wire (4), and the negative terminal of the first LED lamp (11) is connected to the second wire (5); The cathode of the second LED (13) is connected to the first wire (4), and the anode of the second LED (13) is connected to the second wire (5). The cathode of the third LED (12) is connected to the second wire (5), and the anode of the third LED (12) is connected to the third wire (6); The positive terminal of the fourth LED (14) is connected to the second wire (5), and the negative terminal of the fourth LED (14) is connected to the third wire (6); The positive terminal of the fifth LED (21) is connected to the first wire (4), and the negative terminal of the fifth LED (21) is connected to the third wire (6).

7. The lighting control circuit according to claim 6, characterized in that, After the first LED light (11), the second LED light (13), the third LED light (12), the fourth LED light (14), and one or more fifth LED lights (21) are cyclically connected on the wire to form a light string, the first LED light (11), the second LED light (13), the third LED light (12), and the fourth LED light (14) are distributed at equal intervals along the light string, and one or more fifth LED lights (21) are distributed next to the first LED light (11), the second LED light (13), the third LED light (12), and the fourth LED light (14) to form a background light.

8. The lighting control circuit according to claim 6, characterized in that, It also includes a sixth LED (22), the cathode of which is connected to the first wire (4), and the anode of which is connected to the third wire (6).

9. The lighting control circuit according to claim 8, characterized in that, After the first LED light (11), the second LED light (13), the third LED light (12), the fourth LED light (14), one or more fifth LED lights (21) and the sixth LED light (22) are cyclically connected on the wire to form a light string, wherein the first LED light (11), the second LED light (13), the third LED light (12), and the fourth LED light (14) are distributed at equal intervals along the light string, and one or more fifth LED lights (21) and the sixth LED light (22) are distributed next to the first LED light (11), the second LED light (13), the third LED light (12), and the fourth LED light (14) to form a background light.

10. The lighting control circuit according to claim 9, characterized in that, The fifth LED (21) and the sixth LED (22) are packaged together, or the fifth LED (21) and the sixth LED (22) are two LEDs connected in opposite directions in a dual-color lamp.

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