A single live wire multifunctional dimmer

Abstract

The present invention relates to a single live wire multifunctional dimmer, comprising an MCU processing circuit, an AC input protection circuit, a single live wire power supply circuit, an LDO circuit, an automatic phase identification detection circuit, a MOS driving circuit, a MOS dimming circuit, an overload protection circuit, a synchronous signal acquisition circuit, and a brightness adjustment circuit; wherein the automatic phase identification detection circuit can detect the load type, thereby switching a mode that meets the load through the MCU processing circuit. At the same time, the present invention can maintain the ability of the overload point unchanged in different working modes.

Description

Technical Field

[0001] The invention relates to a single-live-wire multifunctional dimmer. Background Art

[0002] The current thyristor dimming driver needs to determine the load type and set the dimmer to the corresponding position due to different loads (inductive loads, such as halogen lamps, capacitive loads, such as LED lamps). Only then will the dimmer and the dimming driver match, and it will be safe to use and the dimming will be smooth. However, it requires very professional personnel to know and set it, and it cannot be used by the public.

[0003] When the load types are different, the OPP (over-power protection point) of the dimmer may differ by 10%, resulting in insufficient protection point accuracy and potential safety hazards.

[0004] At the same time, single live wire power supply usually adopts linear voltage regulator circuit, which has problems of low efficiency, excessive heat, high power component requirements and low safety factor. At the same time, the dimmer is often not matched with the driver at the minimum or maximum brightness, resulting in flickering of the light. Summary of the invention

[0005] The purpose of the present invention is to provide a single live wire multifunctional dimmer which can automatically adjust the working mode according to different load types, and at the same time, the single live wire multifunctional dimmer has the ability to keep the overload point unchanged in different working modes.

[0006] The technical scheme for realizing the purpose of the present invention is as follows: the present invention comprises an MCU processing circuit, an AC input protection circuit, a single live wire power supply circuit, an LDO circuit, an automatic phase identification detection circuit, a MOS drive circuit, a MOS dimming circuit, an overload protection circuit, a synchronization signal acquisition circuit, and a brightness adjustment circuit; the live wire is connected to the input end of the AC input protection circuit, and the output end of the AC protection circuit is respectively connected to the input end of the single live wire power supply circuit, the input end of the MOS dimming circuit, the input end of the automatic phase identification detection circuit, and the input end of the synchronization signal acquisition circuit; the output end of the LDO circuit is respectively connected to the input end of the MOS drive circuit, the input end of the synchronization signal acquisition circuit, the overload protection circuit, and the input end of the synchronization signal acquisition circuit. The output end of the MOS dimming circuit is connected to the input end of the automatic phase identification detection circuit, the input end of the overload protection circuit and the load respectively; the output end of the automatic phase identification detection circuit is connected to the input end of the MCU processing circuit; the output end of the synchronization signal acquisition circuit is connected to the input end of the MCU processing circuit; the output end of the MOS driving circuit is connected to the input end of the MOS dimming circuit; the output end of the overload protection circuit is connected to the input end of the MCU processing circuit, and the output end of the brightness adjustment circuit is connected to the input end of the MCU processing circuit; the output end of the MCU processing circuit is connected to the input end of the MOS driving circuit.

[0007] The above-mentioned automatic phase detection circuit includes a current signal detection circuit and a voltage signal detection circuit; the output end of the MOS dimming circuit includes a current detection interface; the output end of the AC input protection circuit includes a voltage detection interface;

[0008] The current signal detection circuit includes a resistor R27 and a capacitor C16; one end of the resistor R27 is connected to the current detection interface of the MOS dimming circuit, and the other end of the resistor R27 is respectively connected to one end of the capacitor C16 and the input end of the MCU processing circuit; the other end of the capacitor C16 is grounded;

[0009] The above-mentioned voltage signal detection circuit includes resistors R28, R29, R30, R31 and R32 connected in series in sequence; one end of resistor R32 is connected to the voltage detection interface of the AC input protection circuit, and one end of resistor R28 is respectively connected to one end of capacitor C17 and the input end of the MCU processing circuit; the other end of capacitor C17 is grounded.

[0010] The AC input protection circuit is provided with a temperature fuse FU1 and a varistor RV1; the temperature fuse FU1 is in close contact with the field effect transistor.

[0011] The above-mentioned MCU processing circuit includes chip U6, and the model of chip U6 is C8051F996-C-GU; the other end of the resistor R27 is respectively connected to one end of the capacitor C16 and the P1.1 interface of the chip U6; one end of the resistor R28 is respectively connected to one end of the capacitor C17 and the P1.2 interface of the chip U6.

[0012] The above-mentioned overload protection circuit includes resistor R22, resistor R23, resistor R24, capacitor C15, dual voltage comparator U5B, diode D11, and resistor R26; one end of resistor R22 and one end of resistor R23 are connected to the negative electrode of the dual voltage comparator U5B, and the other end of resistor R23 is connected to one end of capacitor C15 and grounded; the other end of capacitor C15 and one end of resistor R24 ​​are connected to the positive electrode of the dual voltage comparator U5B; the other end of resistor R24 ​​is connected to the current detection port of the MOS dimming circuit; the output end of the dual voltage comparator U5B is respectively connected to the negative electrode of diode D11 and the P0.3 interface of chip U6; the positive electrode of diode D11 is connected to one end of resistor R26, and the other end of resistor R26 is connected to the output end of the LDO circuit.

[0013] The brightness adjustment circuit includes an adjustable resistor RW2, an adjustable resistor RW3, a capacitor C18 and a capacitor C19; the first terminal of the adjustable resistor RW2 is connected to the first terminal of the adjustable resistor RW3 and grounded; the third terminal of the adjustable resistor RW2 is connected to one end of the capacitor C18 and the output end of the LDO circuit; the third terminal of the adjustable resistor RW3 is connected to one end of the capacitor C19; one end of the capacitor C18 is connected to one end of the capacitor C19; the other end of the capacitor C18 and the other end of the capacitor C19 are connected to ground; the second terminal of the adjustable resistor RW2 is connected to the P0.4 interface of the chip U6, and the second terminal of the adjustable resistor RW3 is connected to the P0.5 interface of the chip U6. The adjustment range of the adjustable resistors RW2 and RW3 is 30%.

[0014] The above-mentioned single live wire power supply circuit includes capacitor C1, field effect transistor Q1, resistors R2~R7, transistor Q2, diode D6 and voltage-stabilizing diode D3; one end of resistor R2, the positive electrode of capacitor C1 and the D electrode of field effect transistor Q1 are connected and connected to the output end of the AC input protection circuit; the other end of resistor R2 is respectively connected to one end of resistor R3 and one end of resistor R5; the other end of resistor R3 is respectively connected to one end of resistor R4, the negative electrode of voltage-stabilizing diode D3 and the c electrode of transistor Q2; the other end of resistor R4 is connected to the g electrode of field effect transistor Q1; the other end of resistor R5 is respectively connected to the b electrode of transistor Q2 and one end of resistor R6; the other end of resistor R6 is respectively connected to the s electrode of field effect transistor Q1 and one end of resistor R7; the other end of resistor R7 is respectively connected to the e electrode of transistor Q2 and the positive electrode of diode D6; the negative electrode of diode D6 and the positive electrode of voltage-stabilizing diode D3 are both connected to the LDO circuit.

[0015] The synchronous signal acquisition circuit is used to full-wave rectify the grid voltage and sample and shape it into a signal, and then send it to the MCU processing circuit as a reference signal.

[0016] The present invention has positive effects: (1) The present invention can detect the load type by automatically identifying the phase detection circuit, thereby switching the mode that matches the load through the MCU processing circuit; at the same time, it can also maintain the ability of the overload point unchanged in different working modes;

[0017] (2) The present invention automatically identifies the phase detection circuit and transmits the current signal and the voltage signal to the MCU processing circuit, and obtains the load type after processing by the MCU processing circuit, thereby automatically adjusting the working mode, thereby achieving matching and ensuring smooth dimming;

[0018] (3) The AC input protection circuit of the present invention utilizes a temperature fuse to disconnect when the power rises and the field effect tube is overheated, thereby ensuring that the product is not damaged; at the same time, the varistor can absorb the peak when a surge occurs.

[0019] (4) The overload protection circuit of the present invention compares the current sampling with the reference voltage, and when the sampled voltage is higher than the reference, overload protection is performed;

[0020] (5) The brightness adjustment circuit in the present invention is an external circuit of the MCU processing circuit, which plays the role of resistance adjustment, thereby changing the main PWM duty cycle;

[0021] (6) The single live wire power supply circuit in the present invention rectifies 50 Hz alternating current to form a 100 Hz double frequency, and uses 100 Hz to form a switching power supply circuit.

[0022] (7) The present invention can effectively obtain the power grid signal as the reference signal of many signals through the synchronous signal acquisition circuit, thereby ensuring the dimming accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

[0024] Figure 1 A circuit module connection diagram of the present invention;

[0025] Figure 2 A circuit diagram of the present invention;

[0026] Figure 3 A schematic diagram of the MCU processing circuit in the present invention;

[0027] Figure 4 is a schematic diagram of an AC input protection circuit in the present invention;

[0028] Figure 5 It is a schematic diagram of a single live wire power supply circuit in the present invention;

[0029] Figure 6 is a schematic diagram of an LDO circuit in the present invention;

[0030] Figure 7 A schematic diagram of an automatic phase detection circuit in the present invention;

[0031] Figure 8 is a schematic diagram of a MOS driving circuit in the present invention;

[0032] Fig. 9 is a schematic diagram of a MOS dimming circuit in the present invention;

[0033] Fig.10 is a schematic diagram of an overload protection circuit in the present invention;

[0034] Fig.11 is a schematic diagram of a synchronous signal acquisition circuit in the present invention;

[0035] Fig.12 is a schematic diagram of a brightness adjustment circuit in the present invention;

[0036] Fig.13 The flowchart of load identification of the present invention. DETAILED DESCRIPTION

[0037] See Figure 1 and Figure 2 The present invention comprises an MCU processing circuit 1, an AC input protection circuit 2, a single live wire power supply circuit 3, an LDO circuit 4, an automatic phase identification detection circuit 5, a MOS drive circuit 6, a MOS dimming circuit 7, an overload protection circuit 8, a synchronization signal acquisition circuit 9, and a brightness adjustment circuit 10; the live wire is connected to the input end of the AC input protection circuit 2, and the output end of the AC protection circuit 2 is respectively connected to the input end of the single live wire power supply circuit 3, the input end of the MOS dimming circuit 7, the input end of the automatic phase identification detection circuit 5, and the input end of the synchronization signal acquisition circuit 9; the output end of the LDO circuit 4 is respectively connected to the input end of the MOS drive circuit 6, the input end of the synchronization signal acquisition circuit 9, the overload protection circuit 8 The input end of the MOS dimming circuit 7 is connected to the input end of the automatic phase identification detection circuit 5, the input end of the overload protection circuit 8 and the load respectively; the output end of the automatic phase identification detection circuit 5 is connected to the input end of the MCU processing circuit 1; the output end of the synchronization signal acquisition circuit 9 is connected to the input end of the MCU processing circuit 1; the output end of the MOS driving circuit 6 is connected to the input end of the MOS dimming circuit 7; the output end of the overload protection circuit 8 is connected to the input end of the MCU processing circuit 1, and the output end of the brightness adjustment circuit 10 is connected to the input end of the MCU processing circuit 1; the output end of the MCU processing circuit 1 is connected to the input end of the MOS driving circuit 6.

[0038] See Figure 7 , the automatic phase detection circuit 5 includes a current signal detection circuit and a voltage signal detection circuit; the output end of the MOS dimming circuit 7 includes a current detection interface; the output end of the AC input protection circuit 2 includes a voltage detection interface;

[0039] The current signal detection circuit includes a resistor R27 and a capacitor C16; one end of the resistor R27 is connected to the current detection interface of the MOS dimming circuit 7, and the other end of the resistor R27 is respectively connected to one end of the capacitor C16 and the input end of the MCU processing circuit 1; the other end of the capacitor C16 is grounded;

[0040] The voltage signal detection circuit includes a resistor R28, a resistor R29, a resistor R30, a resistor R31 and a resistor R32 connected in series in sequence; one end of the resistor R32 is connected to the voltage detection interface of the AC input protection circuit 2, and one end of the resistor R28 is respectively connected to one end of the capacitor C17 and the input end of the MCU processing circuit; the other end of the capacitor C17 is grounded.

[0041] See Fig. 9 MOS dimming circuit 7 has field effect tube Q3, field effect tube Q4 and resistor R9; the S pole of field effect tube Q3 is connected to one end of resistor R9, and the other end of resistor R9 is connected to the S pole of field effect tube Q4; the current detection interface is at one end where resistor R9 is connected to the S pole of field effect tube Q3. MCU processing circuit 1 adjusts the PWM duty cycle according to the position of main switch resistor RW1A, so that field effect tube Q3 and field effect tube Q4 work in the switching state. The voltage (brightness) to be adjusted is obtained.

[0042] The characteristics of inductive load current lag and voltage lead, and capacitive load current lead and voltage lag are used to switch the front and back. The voltage phasor phase angle is The phase angle of the current phasor is if The circuit is inductive; otherwise, it is capacitive. When it is resistive, it does not distinguish between front and back cutting, because resistive loads are compatible. The current signal is sampled by resistor R9, shaped by resistor R27 and capacitor C16, and the voltage signal is obtained after voltage division by five resistors R28 to R32. In the MCU processing circuit 1, the voltage and current signals to be detected are shaped, and their respective zero-crossing pulses are obtained through the differential circuit, and the analog signal is converted into a discrete digital signal through A / D. The discrete digital signal is subjected to Fourier transformation to directly obtain the phase angle of the fundamental wave. The difference between the phase angles of the two fundamental waves is the phase difference. The accuracy of measuring the phase difference is less than 2 degrees.

[0043] The specific type of load identification process is as follows, see Fig.13 :

[0044] The current signal detection circuit in the automatic phase detection circuit 5 transmits the current signal to the MCU processing circuit 1, and the voltage signal detection circuit in the automatic phase detection circuit 5 transmits the voltage signal to the MCU processing circuit 1. The MCU processing circuit 1 performs a discrete Fourier transform and calculates the phase difference. It is determined whether the phase difference is greater than the leading threshold and less than the trailing threshold. If so, the load is an R-type load; if not, it is determined whether the phase difference is greater than the trailing threshold. If so, the load is a C-type load; if not, it is determined whether the phase difference is less than the leading threshold. If so, the load is an L-type load.

[0045] See Figure 4The AC input protection circuit 2 is provided with a temperature fuse FU1 and a varistor RV1; the temperature fuse FU1 is close to the field effect transistor.

[0046] See Figure 3 The MCU processing circuit 1 includes a chip U6, the model of which is C8051F996-C-GU; the other end of the resistor R27 is respectively connected to one end of the capacitor C16 and the P1.1 interface of the chip U6; one end of the resistor R28 is respectively connected to one end of the capacitor C17 and the P1.2 interface of the chip U6.

[0047] As Fig.11 The synchronous signal acquisition circuit 9 is used to full-wave rectify the grid voltage and sample and shape it into a signal, and then send it to the MCU processing circuit as a reference signal.

[0048] See Fig.10 , the overload protection circuit 8 includes a resistor R22, a resistor R23, a resistor R24, a capacitor C15, a dual voltage comparator U5B, a diode D11, and a resistor R26; one end of the resistor R22 and one end of the resistor R23 are connected to the negative electrode of the dual voltage comparator U5B, and the other end of the resistor R23 is connected to one end of the capacitor C15 and grounded; the other end of the capacitor C15 and one end of the resistor R24 ​​are connected to the positive electrode of the dual voltage comparator U5B; the other end of the resistor R24 ​​is connected to the current detection port of the MOS dimming circuit 7; the output end of the dual voltage comparator U5B is respectively connected to the negative electrode of the diode D11 and the P0.3 interface of the chip U6; the positive electrode of the diode D11 is connected to one end of the resistor R26, and the other end of the resistor R26 is connected to the output end of the LDO circuit 4. The overload protection circuit 8 compares the current sampling with the reference voltage, and when the sampling voltage is higher than the reference, the overload protection is performed. It uses TL431 to generate a reference voltage. The current signal obtained at resistor R9 forms a voltage at resistor R24 ​​and capacitor C15, which is compared in the LM393 comparator.

[0049] See Fig.12 The brightness adjustment circuit 10 includes an adjustable resistor RW2, an adjustable resistor RW3, a capacitor C18 and a capacitor C19; the first terminal of the adjustable resistor RW2 is connected to the first terminal of the adjustable resistor RW3 and grounded; the third terminal of the adjustable resistor RW2 is connected to one end of the capacitor C18 and the output end of the LDO circuit; the third terminal of the adjustable resistor RW3 is connected to one end of the capacitor C19; one end of the capacitor C18 is connected to one end of the capacitor C19; the other end of the capacitor C18 and the other end of the capacitor C19 are connected to ground; the second terminal of the adjustable resistor RW2 is connected to the P0.4 interface of the chip U6, and the second terminal of the adjustable resistor RW3 is connected to the P0.5 interface of the chip U6.

[0050] See Figure 5The single live wire power supply circuit 3 includes a capacitor C1, a field effect transistor Q1, resistors R2 to R7, a transistor Q2, a diode D6 and a voltage-stabilizing diode D3; one end of the resistor R2, the positive electrode of the capacitor C1 and the D electrode of the field effect transistor Q1 are connected and connected to the output end of the AC input protection circuit 2; the other end of the resistor R2 is respectively connected to one end of the resistor R3 and one end of the resistor R5; the other end of the resistor R3 is respectively connected to one end of the resistor R4, the negative electrode of the voltage-stabilizing diode D3 and the C electrode of the transistor Q2; the other end of the resistor R4 is connected to the G electrode of the field effect transistor Q1; the other end of the resistor R5 is respectively connected to the b electrode of the transistor Q2 and one end of the resistor R6; the other end of the resistor R6 is respectively connected to the S electrode of the field effect transistor Q1 and one end of the resistor R7; the other end of the resistor R7 is respectively connected to the e electrode of the transistor Q2 and the positive electrode of the diode D6; the negative electrode of the diode D6 and the positive electrode of the voltage-stabilizing diode D3 are both connected to the LDO circuit 4.

[0051] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A single live wire multifunctional dimmer, characterized in that: It includes an MCU processing circuit, an AC input protection circuit, a single live wire power supply circuit, an LDO circuit, an automatic phase identification detection circuit, a MOS drive circuit, a MOS dimming circuit, an overload protection circuit, a synchronization signal acquisition circuit, and a brightness adjustment circuit; the live wire is connected to the input end of the AC input protection circuit, and the output end of the AC protection circuit is respectively connected to the input end of the single live wire power supply circuit, the input end of the MOS dimming circuit, the input end of the automatic phase identification detection circuit, and the input end of the synchronization signal acquisition circuit; the output end of the LDO circuit is respectively connected to the input end of the MOS drive circuit, the input end of the synchronization signal acquisition circuit, the input end of the overload protection circuit, and the input end of the MCU processing circuit; The output end of the MOS dimming circuit is respectively connected to the input end of the automatic phase identification detection circuit, the input end of the overload protection circuit and the load; the output end of the automatic phase identification detection circuit is connected to the input end of the MCU processing circuit; The output end of the synchronization signal acquisition circuit is connected to the input end of the MCU processing circuit; The output end of the MOS driving circuit is connected to the input end of the MOS dimming circuit; the output end of the overload protection circuit is connected to the input end of the MCU processing circuit, the output end of the brightness adjustment circuit is connected to the input end of the MCU processing circuit; the output end of the MCU processing circuit is connected to the input end of the MOS driving circuit; The automatic phase detection circuit includes a current signal detection circuit and a voltage signal detection circuit; the output end of the MOS dimming circuit includes a current detection interface; the output end of the AC input protection circuit includes a voltage detection interface; The current signal detection circuit includes a resistor R27 and a capacitor C16; one end of the resistor R27 is connected to the current detection interface of the MOS dimming circuit, and the other end of the resistor R27 is respectively connected to one end of the capacitor C16 and the input end of the MCU processing circuit; the other end of the capacitor C16 is grounded; The voltage signal detection circuit includes a resistor R28, a resistor R29, a resistor R30, a resistor R31 and a resistor R32 connected in series in sequence; one end of the resistor R32 is connected to the voltage detection interface of the AC input protection circuit, and one end of the resistor R28 is respectively connected to one end of the capacitor C17 and the input end of the MCU processing circuit; the other end of the capacitor C17 is grounded; The MOS dimming circuit comprises a field effect tube Q3, a field effect tube Q4 and a resistor R9; the S pole of the field effect tube Q3 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the S pole of the field effect tube Q4; the current detection interface is at one end where the resistor R9 is connected to the S pole of the field effect tube Q3; the MCU processing circuit adjusts the PWM duty cycle according to the position of the main switch resistor RW1A, so that the field effect tube Q3 and the field effect tube Q4 work in the switching state; The current signal is sampled by resistor R9, shaped by resistor R27 and capacitor C16, and the voltage signal is obtained after voltage division by five resistors R28~R32. The voltage and current signals to be detected are shaped in the MCU processing circuit, and their respective zero-crossing pulses are obtained through the differential circuit. The analog signal is converted into a discrete digital signal through A / D, and the discrete digital signal is Fourier transformed to directly obtain the phase angle of the fundamental wave. The difference between the phase angles of the two fundamental waves is the phase difference.

2. The single live wire multifunctional dimmer according to claim 1, characterized in that: The AC input protection circuit is provided with a temperature fuse FU1 and a varistor RV1; the temperature fuse FU1 is close to the field effect tube.

3. The single live wire multifunctional dimmer according to claim 1, characterized in that: The MCU processing circuit includes a chip U6, and the model of the chip U6 is C8051F996-C-GU; the other end of the resistor R27 is respectively connected to one end of the capacitor C16 and the P1.1 interface of the chip U6; one end of the resistor R28 is respectively connected to one end of the capacitor C17 and the P1.2 interface of the chip U6.

4. The single live wire multifunctional dimmer according to claim 3, characterized in that: The overload protection circuit includes a resistor R22, a resistor R23, a resistor R24, a capacitor C15, a dual voltage comparator U5B, a diode D11, and a resistor R26; one end of the resistor R22 and one end of the resistor R23 are connected to the negative electrode of the dual voltage comparator U5B, and the other end of the resistor R23 is connected to one end of the capacitor C15 and grounded; the other end of the capacitor C15 and one end of the resistor R24 ​​are connected to the positive electrode of the dual voltage comparator U5B; the other end of the resistor R24 ​​is connected to the current detection port of the MOS dimming circuit; the output end of the dual voltage comparator U5B is respectively connected to the negative electrode of the diode D11 and the P0.3 interface of the chip U6; the positive electrode of the diode D11 is connected to one end of the resistor R26, and the other end of the resistor R26 is connected to the output end of the LDO circuit.

5. The single live wire multifunctional dimmer according to claim 3, characterized in that: The brightness adjustment circuit includes an adjustable resistor RW2, an adjustable resistor RW3, a capacitor C18 and a capacitor C19; the first terminal of the adjustable resistor RW2 is connected to the first terminal of the adjustable resistor RW3 and grounded; the third terminal of the adjustable resistor RW2 is connected to one end of the capacitor C18 and the output end of the LDO circuit; the third terminal of the adjustable resistor RW3 is connected to one end of the capacitor C19; one end of the capacitor C18 is connected to one end of the capacitor C19; the other end of the capacitor C18 and the other end of the capacitor C19 are connected to ground; the second terminal of the adjustable resistor RW2 is connected to the P0.4 interface of the chip U6, and the second terminal of the adjustable resistor RW3 is connected to the P0.5 interface of the chip U6.

6. The single live wire multifunctional dimmer according to claim 1, characterized in that: The single live wire power supply circuit includes a capacitor C1, a field effect transistor Q1, resistors R2~R7, a transistor Q2, a diode D6 and a voltage-stabilizing diode D3; one end of the resistor R2, the positive electrode of the capacitor C1 and the D electrode of the field effect transistor Q1 are connected and connected to the output end of the AC input protection circuit; the other end of the resistor R2 is respectively connected to one end of the resistor R3 and one end of the resistor R5; the other end of the resistor R3 is respectively connected to one end of the resistor R4, the negative electrode of the voltage-stabilizing diode D3 and the C electrode of the transistor Q2; the other end of the resistor R4 is connected to the G electrode of the field effect transistor Q1; the other end of the resistor R5 is respectively connected to the b electrode of the transistor Q2 and one end of the resistor R6; the other end of the resistor R6 is respectively connected to the S electrode of the field effect transistor Q1 and one end of the resistor R7; the other end of the resistor R7 is respectively connected to the e electrode of the transistor Q2 and the positive electrode of the diode D6; the negative electrode of the diode D6 and the positive electrode of the voltage-stabilizing diode D3 are both connected to the LDO circuit.

7. The single live wire multifunctional dimmer according to claim 1, characterized in that: The synchronous signal acquisition circuit is used to full-wave rectify the grid voltage and sample and shape it into a signal, and then send it to the MCU processing circuit as a reference signal.

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