A lighting dimming signal circuit and a dimming method

Abstract

The present invention relates to the field of electronic circuit technology, and specifically to a lighting dimming signal circuit and dimming method, including a signal receiving module, a power conversion module, a central control module, a signal conversion module and a power switch module; the signal receiving module is used to receive an external signal and transmit it to the central control module; the central control module generates a corresponding PWM signal to the signal conversion module according to the external signal received by the signal receiving module; the signal conversion module is used to convert the PWM signal into a voltage signal; the power conversion module is used to supply power to the central control module and the signal receiving module. The present invention can flexibly adjust the frequency and average duty cycle of the PWM signal by setting a signal receiving module, a power conversion module, a central control module, a signal conversion module and a power switch module, and can achieve stable performance and low cost by converting the PWM signal into a 0-10V analog signal for adjustment.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a lighting dimming signal circuit and a dimming method. Background Art

[0002] In the field of lighting, semiconductor lighting, as a new type of light source in the 21st century, has the advantages of energy saving, environmental protection, long life and easy maintenance.

[0003] In order to achieve energy saving, it is necessary to configure a light source driving circuit with a dimming function for the light source so that the brightness of the light source is controlled by a dimming signal. The light source driving circuit is generally configured with a dimming signal input terminal for receiving the dimming signal and adjusting the output of the light source driving circuit according to the dimming signal, thereby adjusting the brightness of the light source to achieve the purpose of saving energy.

[0004] At present, the dimming signal input terminal of the dimming signal input light source driving circuit is a 0-10V dimming signal, and the brightness of the light source changes with the amplitude of the level signal between 0-10V. However, for the trend of digital circuits, it is easier to use PWM. In order to adapt to the PWM dimming signal, it is necessary to design a light source driving circuit corresponding to the PWM dimming signal. Summary of the invention

[0005] The purpose of the present invention is to provide a lighting dimming signal circuit and a dimming method in view of the above-mentioned deficiencies in the prior art.

[0006] The object of the present invention is achieved by the following technical solutions: A lighting dimming signal circuit includes a signal receiving module, a power conversion module, a central control module, a signal conversion module and a power switch module;

[0007] The signal receiving module is used to receive external signals and transmit them to the central control module;

[0008] The central control module generates a corresponding PWM signal to the signal conversion module according to the external signal received by the signal receiving module;

[0009] The signal conversion module is used to convert the PWM signal into a voltage signal;

[0010] The power conversion module is used to convert the mains power into a DC voltage to supply power to the central control module and the signal receiving module;

[0011] The central control module controls the switch of the power conversion module through the power switch module.

[0012] The present invention is further configured that the power conversion module includes a live wire input port, a neutral wire input port, a π-type filter unit, an AC-DC conversion unit, a BUCK step-down unit, an LDO step-down unit, and an output filter unit;

[0013] The live wire input port and the neutral wire input port are respectively connected to the input end of the AC-DC conversion unit; the output end of the AC-DC conversion unit is connected to the input end of the π-type filter unit; the output end of the π-type filter unit is connected to the input end of the BUCK buck unit; the output end of the BUCK buck unit is connected to the input end of the LDO buck unit; the output end of the LDO buck unit is used to supply power to the central control module and the signal receiving module; the output end of the BUCK buck unit is used to supply power to the power switch module; the output filter unit is used to filter the voltage output by the BUCK buck unit and the voltage output by the LDO buck unit.

[0014] The present invention is further configured such that the power conversion module also includes an overcurrent protection unit and a lightning protection unit; the overcurrent protection unit includes a fuse F1; the lightning protection unit includes a discharge tube MOV1; the live wire input port is connected to the neutral wire input port via the fuse F1 and the discharge tube MOV1 in sequence.

[0015] The present invention is further configured such that the AC-DC conversion unit includes a diode D3 and a diode D4; the π-type filter unit includes a capacitor C13, a capacitor C14 and an inductor L1; the BUCK buck unit includes a BUCK buck chip U4, a capacitor C15, a diode D5, a diode D7 and an inductor L2; the LDO buck unit includes an LDO buck chip U3; the output filter unit includes a capacitor C9, a capacitor C12, a capacitor C10 and a capacitor C11;

[0016] The positive electrode of the diode D3 is connected to the live wire input port; the negative electrode of the diode D3 is connected to one end of the inductor L1; the negative electrode of the diode D4 is connected to the neutral wire input port; the positive electrode of the diode D4 is connected to one end of the inductor L1 through the capacitor C13; the positive electrode of the diode D4 is connected to the other end of the inductor L1 through the capacitor C14; the other end of the inductor L1 is connected to the input end of the BUCK buck chip U4; the negative electrode of the diode D5 is connected to the BUCK buck chip U4; the positive electrode of the diode D5 is connected to the power switch module; the negative electrode of the diode D7 is connected to the BUCK buck chip U4; the positive electrode of the diode D7 is connected to the power switch module ... The LDO step-down chip U4 is connected; the cathode of the diode D7 is connected to the cathode of the diode D5 through the capacitor C15; the inductor L2 is arranged between the cathode of the diode D7 and the anode of the diode D5; the anode of the diode D7 is grounded; the input end of the LDO step-down chip U3 is connected to the anode of the diode D5; the output end of the LDO step-down chip U3 is respectively connected to the central control module and the signal receiving module; the input end of the LDO step-down chip U3 is respectively grounded through the capacitor C9 and the capacitor C12; the output end of the LDO step-down chip U3 is respectively grounded through the capacitor C11 and the capacitor C10.

[0017] The present invention is further configured as follows: the central control module includes a control chip U2, a capacitor C5, a capacitor C6, a capacitor C7 and a resistor R6; one end of the capacitor C5 is connected to the power conversion module; the other end of the capacitor C5 is connected to the control chip U2 through the capacitor C7; the capacitor C6 is connected in parallel with the capacitor C5; one end of the resistor R6 is connected to the control chip U2; the other end of the resistor R6 is connected to the power conversion module; the input end of the control chip U2 is connected to the signal receiving module; and the PWM end of the control chip U2 is connected to the signal conversion module.

[0018] The present invention is further configured as follows: the power switch module includes a resistor R5, a transistor Q1, a diode D1 and a relay K1; one end of the resistor R5 is connected to the central control module; the other end of the resistor R5 is connected to the base of the transistor Q1; the emitter of the transistor Q1 is grounded; the collector of the transistor Q1 is connected to the positive electrode of the diode D1; the negative electrode of the diode D1 is connected to the power conversion module; the diode D1 is connected in parallel with the control end of the relay K1; the live wire input port includes an input port J1 and an input port J2; the switch end of the relay K1 is arranged between the input port J1 and the input port J2.

[0019] The present invention is further configured as follows: the signal conversion module includes an operational amplifier U1, a resistor R2, a resistor R1, a capacitor C1, a resistor R4, a resistor R3, a capacitor C3, a capacitor C4, a voltage regulator D2 and a follower U5; one end of the resistor R2 is connected to the central control module; the other end of the resistor R2 is connected to the positive input end of the operational amplifier U1; the positive input end of the operational amplifier U1 is connected to the negative input end of the operational amplifier U1 through the capacitor C1 and the resistor R1 in sequence; the negative input end of the operational amplifier U1 is connected to the output end of the operational amplifier U1 through the resistor R3; the output end of the operational amplifier U1 is grounded to the input end of the follower U5 through the resistor R4; the input end of the follower U5 is grounded through the capacitor C3; the output end of the follower U5 is grounded through the voltage regulator D2; the voltage regulator D2 is connected in parallel with the capacitor C4.

[0020] A dimming method includes a signal receiving module, a power conversion module, a central control module and a signal conversion module;

[0021] The signal receiving module is used to receive external signals and transmit them to the central control module;

[0022] The central control module generates a corresponding PWM signal to the signal conversion module according to the external signal received by the signal receiving module;

[0023] The signal conversion module is used to convert the PWM signal into a voltage signal;

[0024] The power conversion module is used to convert the mains power into a DC voltage to supply power to the central control module and the signal receiving module;

[0025] The central control module is provided with a counter, a register and a comparator;

[0026] The dimming method comprises the following steps:

[0027] A. Set the counter counting frequency;

[0028] B. Set the counter counting period;

[0029] C. Set the comparison value in the register;

[0030] D. The comparator compares the count value of the counter and the comparison value in the register. When the count value is the same as the comparison value, the output level of the central control module changes; when the count value is the same as the period value, the output level of the central control module changes.

[0031] Beneficial effects of the present invention: The present invention can flexibly adjust the frequency and average duty cycle of the PWM signal by setting a signal receiving module, a power conversion module, a central control module, a signal conversion module and a power switch module. By converting the PWM signal into a 0-10V analog signal for adjustment, the performance is stable and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0033] Figure 1 It is a principle block diagram of the present invention;

[0034] Figure 2 is a circuit diagram of a power conversion module of the present invention;

[0035] Figure 3 is a circuit diagram of a signal conversion module of the present invention;

[0036] Figure 4 It is a circuit diagram of the central control module and the power switch module of the present invention;

[0037] Figure 5 It is a principle block diagram of the dimming method of the present invention;

[0038] Figure 6 is a flow chart of the dimming method of the present invention; DETAILED DESCRIPTION

[0039] The present invention is further described in conjunction with the following examples.

[0040] Depend on Figures 1 to 6 It can be seen that the lighting dimming signal circuit described in this embodiment includes a signal receiving module, a power conversion module, a central control module, a signal conversion module and a power switch module;

[0041] The signal receiving module is used to receive external signals and transmit them to the central control module;

[0042] The central control module generates a corresponding PWM signal to the signal conversion module according to the external signal received by the signal receiving module;

[0043] The signal conversion module is used to convert the PWM signal into a voltage signal;

[0044] The power conversion module is used to convert the mains power into a DC voltage to supply power to the central control module and the signal receiving module;

[0045] The central control module controls the switch of the power conversion module through the power switch module.

[0046] Specifically, the lighting dimming signal circuit described in this embodiment can flexibly adjust the frequency and average duty cycle of the PWM signal by setting a signal receiving module, a power conversion module, a central control module, a signal conversion module and a power switch module. By converting the PWM signal into a 0-10V analog signal for adjustment, the performance is stable and the cost is low.

[0047] In the lighting dimming signal circuit described in this embodiment, the power conversion module includes a live line input port, a neutral line input port, a π-type filter unit, an AC-DC conversion unit, a BUCK step-down unit, an LDO step-down unit, and an output filter unit;

[0048] The live wire input port and the neutral wire input port are respectively connected to the input end of the AC-DC conversion unit; the output end of the AC-DC conversion unit is connected to the input end of the π-type filter unit; the output end of the π-type filter unit is connected to the input end of the BUCK buck unit; the output end of the BUCK buck unit is connected to the input end of the LDO buck unit; the output end of the LDO buck unit is used to supply power to the central control module and the signal receiving module; the output end of the BUCK buck unit is used to supply power to the power switch module; the output filter unit is used to filter the voltage output by the BUCK buck unit and the voltage output by the LDO buck unit.

[0049] In the lighting dimming signal circuit described in this embodiment, the power conversion module also includes an overcurrent protection unit and a lightning protection unit; the overcurrent protection unit includes a fuse F1; the lightning protection unit includes a discharge tube MOV1; the live wire input port is connected to the neutral wire input port via the fuse F1 and the discharge tube MOV1 in sequence.

[0050] In the lighting dimming signal circuit described in this embodiment, the AC-DC conversion unit includes a diode D3 and a diode D4; the π-type filter unit includes a capacitor C13, a capacitor C14 and an inductor L1; the BUCK buck unit includes a BUCK buck chip U4, a capacitor C15, a diode D5, a diode D7 and an inductor L2; the LDO buck unit includes an LDO buck chip U3; the output filter unit includes a capacitor C9, a capacitor C12, a capacitor C10 and a capacitor C11;

[0051] The positive electrode of the diode D3 is connected to the live wire input port; the negative electrode of the diode D3 is connected to one end of the inductor L1; the negative electrode of the diode D4 is connected to the neutral wire input port; the positive electrode of the diode D4 is connected to one end of the inductor L1 through the capacitor C13; the positive electrode of the diode D4 is connected to the other end of the inductor L1 through the capacitor C14; the other end of the inductor L1 is connected to the input end of the BUCK buck chip U4; the negative electrode of the diode D5 is connected to the BUCK buck chip U4; the positive electrode of the diode D5 is connected to the power switch module; the negative electrode of the diode D7 is connected to the BUCK buck chip U4; the positive electrode of the diode D7 is connected to the power switch module ... The LDO step-down chip U4 is connected; the cathode of the diode D7 is connected to the cathode of the diode D5 through the capacitor C15; the inductor L2 is arranged between the cathode of the diode D7 and the anode of the diode D5; the anode of the diode D7 is grounded; the input end of the LDO step-down chip U3 is connected to the anode of the diode D5; the output end of the LDO step-down chip U3 is respectively connected to the central control module and the signal receiving module; the input end of the LDO step-down chip U3 is respectively grounded through the capacitor C9 and the capacitor C12; the output end of the LDO step-down chip U3 is respectively grounded through the capacitor C11 and the capacitor C10.

[0052] Specifically, when the fuse F1 of the overcurrent protection unit is short-circuited or overloaded in the system line, a large current flows through the overcurrent protection unit, and the heat generated causes the polymer resin inside the overcurrent protection unit to melt, and the volume grows rapidly, forming a high resistance state, and the working current decreases rapidly, thereby limiting and protecting the circuit. When the fault is eliminated, the material inside the overcurrent protection unit cools and crystallizes again, the volume shrinks, and the conductive particles re-form a conductive path, and the overcurrent protection unit returns to a low resistance state, thereby completing the protection of the circuit without manual replacement.

[0053] When a surge occurs in the system line, the discharge tube MOV1 of the lightning protection unit can effectively clamp the rear-end surge voltage at a lower voltage level. When the voltage applied to the lightning protection unit is lower than its threshold, the current flowing through it is extremely small, which is equivalent to a resistor with infinite resistance. In other words, when the voltage applied to it is lower than its threshold, it is equivalent to a switch in an open state. When the voltage applied to the lightning protection unit exceeds its threshold, the current flowing through it surges, which is equivalent to a resistor with infinite resistance. In other words, when the voltage applied to it is higher than its threshold, it is equivalent to a switch in a closed state. The surge current is discharged through the lightning protection unit, thereby protecting the system circuit.

[0054] The AC-DC conversion unit converts the AC source into a DC current source by utilizing the unidirectional conductivity of the diode D3 and the diode D4, and stabilizes the DC source with a large change to a DC source with a small fluctuation by connecting to the π-type filter unit composed of the capacitor C13, the capacitor C14 and the inductor L1. At the same time, the energy storage characteristics of the capacitor and the inductor are utilized, and the high-speed switch is turned on to stabilize the voltage at a specific voltage value, so as to realize the conversion of the AC mains into a DC stable voltage power supply to provide energy for each component of the system; and the capacitor C9, the capacitor C12, the capacitor C10 and the capacitor C11 filter the two different voltage sources of the step-down respectively, so as to make the power supply more stable.

[0055] In the lighting dimming signal circuit described in this embodiment, the central control module includes a control chip U2, a capacitor C5, a capacitor C6, a capacitor C7 and a resistor R6; one end of the capacitor C5 is connected to the power conversion module; the other end of the capacitor C5 is connected to the control chip U2 through the capacitor C7; the capacitor C6 is connected in parallel with the capacitor C5; one end of the resistor R6 is connected to the control chip U2; the other end of the resistor R6 is connected to the power conversion module; the input end of the control chip U2 is connected to the signal receiving module; the PWM end of the control chip U2 is connected to the signal conversion module.

[0056] Among them, the control chip U2 is a single-chip microcomputer; capacitors C5 and C6 filter the power supply of the control chip U2, and the function of capacitor C7 is to ensure the voltage stability of the main voltage regulator inside the control chip U2; resistor R6 ensures that the signal of the control chip U2 maintains a high level state when there is no signal output; and P1 in the figure is a signal receiving module, which can convert the ambient brightness signal or user setting information into the corresponding switch and dimming signals after being processed by the control chip U2.

[0057] In the lighting dimming signal circuit described in this embodiment, the power switch module includes a resistor R5, a transistor Q1, a diode D1 and a relay K1; one end of the resistor R5 is connected to the central control module; the other end of the resistor R5 is connected to the base of the transistor Q1; the emitter of the transistor Q1 is grounded; the collector of the transistor Q1 is connected to the positive electrode of the diode D1; the negative electrode of the diode D1 is connected to the power conversion module; the diode D1 is connected in parallel with the control end of the relay K1; the live wire input port includes an input port J1 and an input port J2; the switch end of the relay K1 is arranged between the input port J1 and the input port J2.

[0058] Specifically, the switch signal controlled by the control chip U2 drives the transistor Q1 to turn on or off the control end of the relay K1 after current limiting by the resistor R5, so as to switch the control end of the relay K1 to control the high voltage with a low voltage. The diode D1 is a reverse diode, which is used to protect the relay K1 from possible damage caused by the reverse electromotive force at the moment of turning off, thereby controlling the opening and closing of the switch end of the relay K1.

[0059] A lighting dimming signal circuit described in this embodiment, the signal conversion module includes an operational amplifier U1, a resistor R2, a resistor R1, a capacitor C1, a resistor R4, a resistor R3, a capacitor C3, a capacitor C4, a voltage regulator D2 and a follower U5; one end of the resistor R2 is connected to the central control module; the other end of the resistor R2 is connected to the positive input end of the operational amplifier U1; the positive input end of the operational amplifier U1 is connected to the negative input end of the operational amplifier U1 through the capacitor C1 and the resistor R1 in sequence; the negative input end of the operational amplifier U1 is connected to the output end of the operational amplifier U1 through the resistor R3; the output end of the operational amplifier U1 is grounded to the input end of the follower U5 through the resistor R4; the input end of the follower U5 is grounded through the capacitor C3; the output end of the follower U5 is grounded through the voltage regulator D2; the voltage regulator D2 is connected in parallel with the capacitor C4.

[0060] Specifically, operational amplifier U1, resistor R1, resistor R2, resistor R3 and capacitor C1 form a signal amplification circuit to amplify the PWM signal output by control chip U2. Resistor R4 and capacitor C3 form an RC filter to convert the PWM signal into a relatively stable voltage signal, which is input into voltage follower U5. Signal fluctuations are further stabilized by capacitor C4. Zener diode D2 is a Schottky diode, which limits the output voltage to prevent the 0-10V signal voltage from being too high.

[0061] A dimming method described in this embodiment includes a signal receiving module, a power conversion module, a central control module and a signal conversion module;

[0062] The signal receiving module is used to receive external signals and transmit them to the central control module;

[0063] The central control module generates a corresponding PWM signal to the signal conversion module according to the external signal received by the signal receiving module;

[0064] The signal conversion module is used to convert the PWM signal into a voltage signal;

[0065] The power conversion module is used to convert the mains power into a DC voltage to supply power to the central control module and the signal receiving module;

[0066] The central control module is provided with a counter, a register and a comparator;

[0067] The dimming method comprises the following steps:

[0068] A. Set the counter counting frequency;

[0069] B. Set the counter counting period;

[0070] C. Set the comparison value in the register;

[0071] D. The comparator compares the count value of the counter and the comparison value in the register. When the count value is the same as the comparison value, the output level of the central control module changes; when the count value is the same as the period value, the output level of the central control module changes.

[0072] Specifically, the dimming method is a pulse width modulation method to generate a fixed frequency pulse square wave signal, specifically a clock signal with equal high and low level durations, which is used for internal circuit counting and timing. The counter starts counting from 0 and counts to a set period value T and then starts counting from 0 again. A comparison value CMP can be set in the register. When the count value of the counter is equal to the comparison value, the PWM port outputs a low level; when the counter counts to the period value, the PWM port outputs a high level. In this way, a pulse signal with a period proportional to the comparison register value is generated. The process of counting and matching output is repeated in the comparison unit to generate a PWM signal. When the system receives a signal from the sensor or the user setting requiring a switch / dimming change, the signal reception and processing are processed in an interrupt manner to determine whether the signal has changed from the current setting value. If there is a change, it is set to the corresponding value. If there is no change, the setting is skipped and the next judgment is continued. After the processing is completed, the previous program is returned to the loop to continue running.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A lighting dimming signal circuit, characterized in that: It includes a signal receiving module, a power conversion module, a central control module, a signal conversion module and a power switch module; The signal receiving module is used to receive external signals and transmit them to the central control module; The central control module generates a corresponding PWM signal to the signal conversion module according to the external signal received by the signal receiving module; The signal conversion module is used to convert the PWM signal into a voltage signal; The power conversion module is used to convert the mains power into a DC voltage to supply power to the central control module and the signal receiving module; The central control module controls the switch of the power conversion module through the power switch module; The power conversion module includes a live line input port, a neutral line input port, a π-type filter unit, an AC-DC conversion unit, a BUCK step-down unit, an LDO step-down unit and an output filter unit; The live wire input port and the neutral wire input port are respectively connected to the input end of the AC-DC conversion unit; the output end of the AC-DC conversion unit is connected to the input end of the π-type filter unit; the output end of the π-type filter unit is connected to the input end of the BUCK buck unit; the output end of the BUCK buck unit is connected to the input end of the LDO buck unit; the output end of the LDO buck unit is used to supply power to the central control module and the signal receiving module; the output end of the BUCK buck unit is used to supply power to the power switch module; the output filter unit is used to filter the voltage output by the BUCK buck unit and the voltage output by the LDO buck unit; The power conversion module also includes an overcurrent protection unit and a lightning protection unit; the overcurrent protection unit includes a fuse F1; the lightning protection unit includes a discharge tube MOV1; the live wire input port is connected to the neutral wire input port through the fuse F1 and the discharge tube MOV1 in sequence; The central control module includes a control chip U2, a capacitor C5, a capacitor C6, a capacitor C7 and a resistor R6; one end of the capacitor C5 is connected to the power conversion module; the other end of the capacitor C5 is connected to the control chip U2 through the capacitor C7; the capacitor C6 is connected in parallel with the capacitor C5; one end of the resistor R6 is connected to the control chip U2; the other end of the resistor R6 is connected to the power conversion module; the input end of the control chip U2 is connected to the signal receiving module; the PWM end of the control chip U2 is connected to the signal conversion module.

2. A lighting dimming signal circuit according to claim 1, characterized in that: The AC-DC conversion unit includes a diode D3 and a diode D4; the π-type filter unit includes a capacitor C13, a capacitor C14 and an inductor L1; the BUCK buck unit includes a BUCK buck chip U4, a capacitor C15, a diode D5, a diode D7 and an inductor L2; the LDO buck unit includes an LDO buck chip U3; the output filter unit includes a capacitor C9, a capacitor C12, a capacitor C10 and a capacitor C11; The positive electrode of the diode D3 is connected to the live wire input port; the negative electrode of the diode D3 is connected to one end of the inductor L1; the negative electrode of the diode D4 is connected to the neutral wire input port; the positive electrode of the diode D4 is connected to one end of the inductor L1 through the capacitor C13; the positive electrode of the diode D4 is connected to the other end of the inductor L1 through the capacitor C14; the other end of the inductor L1 is connected to the input end of the BUCK buck chip U4; the negative electrode of the diode D5 is connected to the BUCK buck chip U4; the positive electrode of the diode D5 is connected to the power switch module; the negative electrode of the diode D7 is connected to the BUCK buck chip U4; the positive electrode of the diode D7 is connected to the power switch module ... The LDO step-down chip U4 is connected; the cathode of the diode D7 is connected to the cathode of the diode D5 through the capacitor C15; the inductor L2 is arranged between the cathode of the diode D7 and the anode of the diode D5; the anode of the diode D7 is grounded; the input end of the LDO step-down chip U3 is connected to the anode of the diode D5; the output end of the LDO step-down chip U3 is respectively connected to the central control module and the signal receiving module; the input end of the LDO step-down chip U3 is respectively grounded through the capacitor C9 and the capacitor C12; the output end of the LDO step-down chip U3 is respectively grounded through the capacitor C11 and the capacitor C10.

3. The lighting dimming signal circuit according to claim 1, characterized in that: The power switch module includes a resistor R5, a transistor Q1, a diode D1 and a relay K1; one end of the resistor R5 is connected to the central control module; the other end of the resistor R5 is connected to the base of the transistor Q1; the emitter of the transistor Q1 is grounded; the collector of the transistor Q1 is connected to the positive electrode of the diode D1; the negative electrode of the diode D1 is connected to the power conversion module; the diode D1 is connected in parallel with the control end of the relay K1; the live wire input port includes an input port J1 and an input port J2; the switch end of the relay K1 is arranged between the input port J1 and the input port J2.

4. The lighting dimming signal circuit according to claim 1, characterized in that: The signal conversion module includes an operational amplifier U1, a resistor R2, a resistor R1, a capacitor C1, a resistor R4, a resistor R3, a capacitor C3, a capacitor C4, a voltage regulator D2 and a follower U5; one end of the resistor R2 is connected to the central control module; the other end of the resistor R2 is connected to the positive input end of the operational amplifier U1; the positive input end of the operational amplifier U1 is connected to the negative input end of the operational amplifier U1 through the capacitor C1 and the resistor R1 in sequence; the negative input end of the operational amplifier U1 is connected to the output end of the operational amplifier U1 through the resistor R3; the output end of the operational amplifier U1 is grounded to the input end of the follower U5 through the resistor R4; the input end of the follower U5 is grounded through the capacitor C3; the output end of the follower U5 is grounded through the voltage regulator D2; the voltage regulator D2 is connected in parallel with the capacitor C4.

5. A dimming method based on the lighting dimming signal circuit according to any one of claims 1 to 4, characterized in that: It includes a signal receiving module, a power conversion module, a central control module and a signal conversion module; The signal receiving module is used to receive external signals and transmit them to the central control module; The central control module generates a corresponding PWM signal to the signal conversion module according to the external signal received by the signal receiving module; The signal conversion module is used to convert the PWM signal into a voltage signal; The power conversion module is used to convert the mains power into a DC voltage to supply power to the central control module and the signal receiving module; The central control module is provided with a counter, a register and a comparator; The dimming method comprises the following steps: A. Set the counter counting frequency; B. Set the counter counting period; C. Set the comparison value in the register; D. The comparator compares the count value of the counter and the comparison value in the register. When the count value is the same as the comparison value, the output level of the central control module changes; when the count value is the same as the period value, the output level of the central control module changes.

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