Single-live-wire trailing-edge wall dimmer

Abstract

Provided in the present invention is a single-live-wire trailing-edge wall dimmer. The dimmer comprises: a MOS transistor switching circuit unit, a single-chip microcomputer control unit, and a direct-current power supply unit. The direct-current power supply unit comprises: an alternating-current voltage waveform collection circuit, a direct-current voltage drop circuit, an overcurrent protection circuit, and a filtering and voltage stabilization circuit. The single-chip microcomputer control unit comprises: a single-chip microcomputer, a potentiometer, a triode Q6, a triode Q5 and a triode Q7, wherein a PC2 terminal of the single-chip microcomputer is connected to the potentiometer, and a voltage collected at the PC2 terminal changes when the resistance value of the potentiometer changes; a PA6 terminal of the single-chip microcomputer outputs different voltage signals to control the turning on / off of the triode Q6, the triode Q5 and the triode Q7, so as to adjust the turning on / off times of MOS transistors; an output terminal of the alternating-current voltage waveform collection circuit is connected to a PC1 terminal of the single-chip microcomputer, so as to provide a phase reference; and after an alternating current passes through the direct-current power supply unit, a 5V direct current is output, and is connected to a VDD terminal of the single-chip microcomputer, so as to supply power to the single-chip microcomputer. The dimmer is capable of stable dimming at low brightness.

Description

A post-phase single-fire wall dimmer Technical Field

[0001] This invention relates to a dimming product that is fixedly installed in a wall junction box, specifically, to a post-phase-cut single-fire wall dimmer. Background Technology

[0002] A dimmer is a device used to adjust the brightness of lighting equipment to meet the lighting needs of different scenarios. Dimmers are widely used in homes, offices, commercial buildings, and other places, providing a comfortable and adjustable lighting environment. Currently, most dimmers on the market use silicon controlled rectifiers (SCRs) as the switching device, resulting in a relatively simple dimming circuit. However, because SCR dimming controls LED brightness by changing the leading edge of the voltage waveform, flickering or jittering may occur at low brightness levels.

[0003] Therefore, there is an urgent need for a dimmer that is simple in structure, highly compatible, and can stably dim at low brightness. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a back-cut single-fire wall dimmer, the size of which is designed according to the space of the junction box, and uses a MOSFET instead of a thyristor as the switching device. Since MOSFET dimming controls LED brightness by changing the trailing edge of the voltage waveform, there will be no light flickering or jittering under low brightness conditions. This dimmer greatly improves the compatibility with lighting fixtures and effectively solves the problem of light flickering under low brightness conditions, thus improving the compatibility with lighting fixtures.

[0005] To achieve the above objectives, the present invention provides a post-phase-cut single-fire wall dimmer, comprising a MOSFET switching circuit unit, a microcontroller control unit, and a DC power supply unit, wherein:

[0006] The MOSFET switching circuit unit includes:

[0007] Connect terminal J2 to the power supply live wire. Terminal J2 is connected to the drain of MOSFET Q1. The gate of MOSFET Q1 is connected to the gate of MOSFET Q2 after being connected in series with resistors R7, R8, R9, and R10. The drain of MOSFET Q2 is connected to the anode of diode D2. The cathode of diode D2 is connected to the cathode of diode D1.

[0008] A single-pole double-throw switch has its stationary contact connected to the drain of MOSFET Q2, its first moving contact connected to terminal J1, and its second moving contact connected to terminal J3, so that the single-pole double-throw switch can selectively conduct with terminal J1 or terminal J3.

[0009] The microcontroller control unit includes:

[0010] A microcontroller has its VDD terminal as the power supply terminal, which is connected to the output terminal of a DC power supply unit; the PC1 terminal of the microcontroller is the AC signal acquisition terminal; the PC2 terminal of the microcontroller is the transformer signal acquisition terminal; and the PA6 terminal of the microcontroller is the voltage signal output terminal.

[0011] The sliding potentiometer changes its resistance value by sliding the dimming handle. Resistor R17 is connected in series with the sliding potentiometer and then connected to the PC2 terminal of the microcontroller. The rotary potentiometer changes its resistance value by rotating the adjustment dial. Resistor R19, the sliding potentiometer, and the rotary potentiometer are connected in series between the output terminal of the DC power supply unit and ground.

[0012] Transistors Q6, Q5, and Q7 are used. The collector of transistor Q6 is connected to resistor R11 and then to the anode of diode D6. The cathode of D6 is connected to resistor R12 and then to the base of transistor Q6. The base of transistor Q6 is connected to the base of transistor Q5 and then to the collector of transistor Q7. The base of transistor Q7 is connected in series with resistor R15 and then to the PA6 terminal of the microcontroller. A lead is made between the emitters of transistors Q6 and Q5 and connected to resistors R8 and R9 to connect the MOSFET switching circuit unit to the microcontroller control unit.

[0013] The DC power supply unit includes: an AC voltage waveform acquisition circuit, a DC voltage drop circuit, an overcurrent protection circuit, and a filter and voltage regulation circuit, wherein:

[0014] The AC voltage waveform acquisition circuit includes: a diode D1 connected to terminal J2, resistors R13, R18 and R14 connected in series from the cathode of diode D1, and then grounded; the wiring between resistors R18 and R14 is connected to the PC1 terminal of the microcontroller to acquire AC voltage waveform.

[0015] The DC voltage drop circuit includes: a transistor Q3, with resistors R1, R2 and R3 connected in series between its collector and base; and a three-terminal regulator whose cathode is connected to the base of transistor Q3.

[0016] The overcurrent protection circuit includes: the emitter of transistor Q4 is connected to ground via resistors R5 and R6 in series; the wire leading out between resistors R5 and R6 is connected to the reference terminal of the three-terminal regulator.

[0017] The filtering and voltage regulation circuit includes: a low-dropout linear regulator, with capacitors C6 and C7 connected in parallel between its input terminal and ground terminal, and capacitor C8 connected in parallel between the output terminal of the low-dropout linear regulator and ground terminal; wherein, the input terminal of the low-dropout linear regulator is connected to the emitter of transistor Q4;

[0018] In one embodiment of the present invention, the MOS transistor switching circuit unit further includes: a wire leading from resistor R7 to the gate of MOS transistor Q1 is connected to the anode of diode D4, and the cathode of diode D4 is connected to the wire leading from resistor R7 and resistor R8; a wire leading from resistor R10 to the gate of MOS transistor Q2 is connected to the anode of diode D3, and the cathode of diode D3 is connected to the wire leading from resistor R9 and resistor R10; the source of MOS transistor Q1 and the source of MOS transistor Q2 are both grounded;

[0019] In one embodiment of the present invention, the single-chip microcomputer control unit further includes: the adjustment dial of the rotary potentiometer is connected to the resistive element of the rotary potentiometer via a connecting rod, and capacitors C3 and C4 are connected in parallel between the variable resistance terminal of the sliding potentiometer and the variable resistance terminal of the rotary potentiometer.

[0020] In one embodiment of the present invention, the microcontroller control unit further includes: the emitter of transistor Q6 is connected to the emitter of transistor Q5; the collector of transistor Q5 and the emitter of transistor Q7 are both grounded;

[0021] In one embodiment of the present invention, the AC voltage waveform acquisition circuit further includes a capacitor C5 and a Zener diode D5 connected in parallel across the two ends of the resistor R14.

[0022] In one embodiment of the present invention, the DC voltage drop circuit further includes: the emitter of transistor Q3 is connected to the base of transistor Q4; the anode of the three-terminal regulator is grounded;

[0023] In one embodiment of the present invention, the overcurrent protection circuit further includes a resistor R4 connected between the base and emitter of the transistor Q4.

[0024] In one embodiment of the present invention, the filtering and voltage regulation circuit further includes: grounding the grounding terminal of a low-dropout linear regulator.

[0025] Compared with existing dimmers, the post-phase single-fire wall dimmer provided by this invention uses a MOSFET as a switching device. Therefore, the output power can be controlled by adjusting the conduction angle of the MOSFET to change the intensity of the light, thus effectively solving the problem of light flickering at low brightness. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 is a circuit schematic diagram of an embodiment of the present invention.

[0028] Figure 2 is a circuit diagram of a MOS transistor switching circuit unit in one embodiment of the present invention.

[0029] Figure 3 is a circuit diagram of a microcontroller control unit according to an embodiment of the present invention.

[0030] Figure 4 is a circuit diagram of a DC power supply unit according to an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Figure 1 is a circuit diagram of an embodiment of the present invention. As shown in Figure 1, this embodiment provides a back-cut single-fire wall dimmer, which includes a MOS transistor switching circuit unit, a DC power supply unit, and a microcontroller control unit. The dimmer in this embodiment is used as a single dimming switch, wherein:

[0033] Figure 2 is a circuit diagram of a MOS transistor switching circuit unit according to an embodiment of the present invention. As shown in Figure 2, the MOS transistor switching circuit unit includes: a terminal J2 connected to the power supply live wire; terminal J2 is connected to the drain (pin 2) of MOS transistor Q1; the gate (pin 1) of MOS transistor Q1 is connected to the gate (pin 1) of MOS transistor Q2 after being connected in series with resistors R7, R8, R9, and R10; the drain (pin 2) of MOS transistor Q2 is connected to the anode of diode D2; the cathode of diode D2 is connected to the cathode of diode D1; the source (pin 3) of MOS transistor Q1 and the source (pin 3) of MOS transistor Q2 are both grounded; a wire is led out between resistor R7 and the gate (pin 1) of MOS transistor Q1 and connected to the anode of diode D4; the cathode of diode D4 is connected to the wire led out between resistors R7 and R8; a wire is led out between resistor R10 and the gate (pin 1) of MOS transistor Q2 and connected to the anode of diode D3; the cathode of diode D3 is connected to the wire led out between resistors R9 and R10.

[0034] The stationary contact 2 of the single-pole double-throw switch S1 is connected to the drain (pin 2) of the MOSFET Q2. Terminal J1 is connected to the moving contact 1 (first moving contact) of the single-pole double-throw switch S1, and terminal J3 is connected to the moving contact 3 (second moving contact) of the single-pole double-throw switch S1, so that the single-pole double-throw switch S1 can selectively conduct with terminal J1 or terminal J3. When the dimmer is used as a unit dimmer switch, the live wire of the lamp can be connected to terminal J1 or terminal J3, and the corresponding single-pole double-throw switch S1 should also be connected to the corresponding moving contact 1 or moving contact 3 to achieve the purpose of connecting the dimmer and the lamp.

[0035] When the voltage flowing through terminal J2 is positive, MOSFETs Q1 and Q2 are simultaneously turned on. Current flows from MOSFET Q1 (turned on during the positive half-cycle) through the built-in forward diode of MOSFET Q2 to terminal J1 or terminal J3. When the voltage flowing through terminal J2 is negative, current flows from MOSFET Q2 (turned on during the negative half-cycle) through the built-in reverse diode of MOSFET Q1 to terminal J2.

[0036] Figure 3 is a circuit diagram of a microcontroller control unit according to an embodiment of the present invention. As shown in Figure 3, the microcontroller control unit circuit includes: a microcontroller U1, which has 8 pins. Pin 1 (VDD) of the microcontroller U1 is the power supply terminal of the microcontroller U1, and the output of the DC power supply unit is connected to this pin; pin 5 (PC1) of the microcontroller U1 is the AC signal acquisition terminal; pin 4 (PC2) of the microcontroller U1 is the transformer signal acquisition terminal; and pin 2 (PA6) of the microcontroller U1 is the voltage signal output terminal.

[0037] A resistor R19, a sliding potentiometer VR1, and a rotary potentiometer VR2 are connected in series between the output voltage of the DC power supply unit and ground. The sliding potentiometer VR1 can change its resistance value by sliding the dimming handle. The sliding potentiometer VR1 is connected in series with a resistor R17 and then connected to pin 4 (PC2) of the microcontroller U1. When the resistance value of the potentiometer changes, pin 2 (PA6) of the microcontroller can output different voltage signals. The adjustment dial of the rotary potentiometer VR2 is connected to the resistive element of the rotary potentiometer via a connecting rod. Rotating the adjustment dial changes the resistance value of the rotary potentiometer. Capacitors C3 and C4 are connected in parallel between the variable resistor terminals of the sliding potentiometer and the rotary potentiometer.

[0038] Transistors Q6, Q5, and Q7 are used. The collector (pin 2) of transistor Q6 is connected to resistor R11 and then to the anode of diode D6. The cathode of D6 is connected to resistor R12 and then to the base (pin 1) of transistor Q6. The base (pin 1) of transistor Q6 is connected to the base (pin 1) of transistor Q5 and then to the collector (pin 2) of transistor Q7. The base (pin 1) of transistor Q7 is connected in series with resistor R15 and then to pin 2 (PA6) of microcontroller U1. A wire is led out between the emitters (pin 3) of transistor Q6 and Q5 and connected to resistors R8 and R9 to connect the MOSFET switching circuit unit to the microcontroller control unit. The emitter (pin 3) of transistor Q6 is connected to the emitter (pin 3) of transistor Q5. The collector (pin 2) of transistor Q5 and the emitter (pin 3) of transistor Q7 are both grounded.

[0039] Figure 4 is a circuit diagram of a DC power supply unit according to an embodiment of the present invention. As shown in Figure 4, the DC power supply unit includes: an AC voltage waveform acquisition circuit, a DC voltage drop circuit, an overcurrent protection circuit, and a filter and voltage regulation circuit, wherein:

[0040] The AC voltage waveform acquisition circuit includes: a diode D1 connected to terminal J2, followed by resistors R13, R18, and R14 connected in series and then grounded; a wire is led out between resistors R18 and R14 and connected to pin 5 PC1 of microcontroller U1 to acquire AC voltage waveforms as a phase reference for the signal output of microcontroller U1; and a capacitor C5 and a Zener diode D5 are connected in parallel across resistor R14.

[0041] The DC voltage drop circuit includes: a transistor Q3, with resistors R1, R2, and R3 connected in series between its collector (pin 2) and base (pin 1); the emitter (pin 3) of transistor Q3 is connected to the base (pin 1) of transistor Q4; the cathode (pin 3) of a three-terminal regulator T1 is connected to the base (pin 1) of transistor Q3; the anode (pin 2) of the three-terminal regulator T1 is grounded; the AC power from the live wire is output as a 10V DC voltage after passing through the DC voltage drop circuit, which is connected to the anode of diode D6 and R11 to power the MOSFET switching circuit unit.

[0042] The overcurrent protection circuit includes: a transistor Q4, whose emitter (pin 3) is connected to ground via a series connection of resistors R5 and R6; a wire is led out between resistors R5 and R6 and connected to the reference terminal (pin 1) of a three-terminal regulator T1; resistor R4 is connected between the base (pin 1) and emitter (pin 3) of transistor Q4; and the base (pin 1) of transistor Q4 is connected to the emitter (pin 3) of transistor Q3.

[0043] The filtering and voltage regulation circuit includes: a low-dropout linear regulator V1, with capacitors C6 and C7 connected in parallel between its input terminal (pin 2) and its ground terminal (pin 1); a capacitor C8 connected in parallel between its output terminal (pin 3) and its ground terminal (pin 1); and the ground terminal (pin 1) of the low-dropout linear regulator V1 connected to ground. The input terminal (pin 2) of the low-dropout linear regulator V1 is connected to the emitter (pin 3) of transistor Q4. The 10V DC voltage is reduced to 5V DC after passing through the low-dropout linear regulator V1. This 5V DC voltage, through resistor R19, a sliding potentiometer VR1, and a rotary potentiometer VR2, provides a reference voltage to the PC2 terminal of the microcontroller U1.

[0044] The current input from the live wire of the power supply passes through the positive diode D1 and then through resistors R3 and R2 to the base (pin 1) of transistor Q3, turning on transistor Q3. The current then flows through the emitter (pin 3) of transistor Q3 to the base (pin 1) of transistor Q4, turning on transistor Q4. The current then flows through the emitter (pin 3) of transistor Q4 to the input of low dropout linear regulator V1. The output of low dropout linear regulator V1 is connected to pin 1 (VDD) of microcontroller U1.

[0045] To better understand the dimmer of the present invention, the working principle of the dimmer is explained below:

[0046] When the dimmer is used as a unit dimming switch, the customer moves the dimming handle according to the needs. The voltage at pin 4 (PC2) of the microcontroller U1 changes according to the resistance of the sliding potentiometer VR1 and the rotary potentiometer VR2. The microcontroller U1 outputs different voltage signals at pin 2 (PA6). When the voltage signal is low, transistors Q7 and Q5 are cut off. The 10V DC voltage is connected to the base (pin 1) of transistor Q6 via diode D6 (connected in positive direction) and resistor R12, making Q6 conduct. The current from the emitter (pin 3) of transistor Q6 controls the conduction of MOSFET Q2 through resistors R9 and R10, and controls the conduction of MOSFET Q1 through resistors R8 and R7. The different widths of the low-level signal result in different cut-off times for transistor Q7, i.e., different conduction times for MOSFETs Q1 and Q2. The longer the conduction time of MOSFETs Q1 and Q2 within a voltage cycle, the greater the current, i.e., the higher the brightness of the load lamp. The brightness of the lamp can be changed by altering the width of the low-level signal emitted from pin 2 (PA6) of microcontroller U1, thus achieving dimming.

[0047] In another embodiment of the present invention, the dimmer can also be used as a three-position dimmer switch. When the dimmer is used as a three-position dimmer switch, it is also necessary to use it in conjunction with an ordinary three-position switch. The terminals J1 and J3 are respectively connected to the two separate terminals of the ordinary three-position switch. At this time, the working principle of the dimmer is the same as when the dimmer is used as a unit dimmer switch.

[0048] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0049] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A trailing edge single phase wall dimmer, characterized by, It includes a MOSFET switching circuit unit, a DC power supply unit, and a microcontroller control unit, wherein: The MOSFET switching circuit unit includes: The terminal J2 is connected to the power supply live wire. The terminal J2 is connected to the drain of MOSFET Q1. The gate of MOSFET Q1 is connected to the gate of MOSFET Q2 after being connected in series with resistors R7, R8, R9, and R10. The drain of MOSFET Q2 is connected to the anode of diode D2. The cathode of diode D2 is connected to the cathode of diode D1. A single-pole double-throw switch has its stationary contact connected to the drain of a MOSFET Q2. The first moving contact of the single-pole double-throw switch is connected to terminal J1, and the second moving contact of the single-pole double-throw switch is connected to terminal J3, so that the single-pole double-throw switch can selectively conduct with terminal J1 or terminal J3. The microcontroller control unit includes: A microcontroller, whose VDD terminal is the power supply terminal of the microcontroller and is connected to the output terminal of the DC power supply unit; the PC1 terminal of the microcontroller is the AC voltage waveform acquisition terminal; the PC2 terminal of the microcontroller is the transformer signal acquisition terminal; and the PA6 terminal of the microcontroller is the voltage signal output terminal. A linear potentiometer and a rotary potentiometer are provided. The linear potentiometer changes its resistance by sliding a dimming handle. The linear potentiometer is connected in series with resistor R17 and then connected to the PC2 terminal of the microcontroller. The rotary potentiometer changes its resistance by rotating an adjustment dial. Resistor R19, the linear potentiometer, and the rotary potentiometer are connected in series between the output terminal of the DC power supply unit and ground. Transistors Q6, Q5, and Q7 are used, wherein the collector of transistor Q6 is connected to the anode of diode D6 via resistor R11, and the cathode of D6 is connected to the base of transistor Q6 via resistor R12; the base of transistor Q6 is connected to the base of transistor Q5 and then to the collector of transistor Q7; the base of transistor Q7 is connected to the PA6 terminal of the microcontroller via resistor R15 in series; and a lead is made between the emitters of transistor Q6 and Q5 and connected to resistors R8 and R9. The DC power supply unit includes: an AC voltage waveform acquisition circuit, a DC voltage drop circuit, an overcurrent protection circuit, and a filter and voltage regulation circuit.

2. The single-fire wall dimmer according to claim 1, characterized in that, The AC voltage waveform acquisition circuit includes: a diode D1 that is positively connected to the terminal J2; resistors R13, R18, and R14 connected in series from the cathode of diode D1, and then grounded; the wiring between resistors R18 and R14 is connected to the PC1 terminal of the microcontroller. The DC voltage drop circuit includes: a transistor Q3, with resistors R1, R2 and R3 connected in series between its collector and base; and a three-terminal regulator, with its cathode connected to the base of transistor Q3. The overcurrent protection circuit includes: a transistor Q4, whose emitter is connected in series with resistors R5 and R6 and then grounded; the wiring between resistors R5 and R6 is connected to the reference terminal of the three-terminal regulator. The filtering and voltage regulation circuit includes: a low-dropout linear regulator, with capacitors C6 and C7 connected in parallel between its input terminal and ground terminal, and capacitor C8 connected in parallel between the output terminal of the low-dropout linear regulator and ground terminal; wherein, the input terminal of the low-dropout linear regulator is connected to the emitter of transistor Q4.

3. The trailing edge phase single fire wall dimmer of claim 1 wherein, The wire leading from resistor R7 to the gate of MOSFET Q1 is connected to the anode of diode D4, and the cathode of diode D4 is connected to the wire leading from resistors R7 and R8; the wire leading from resistor R10 to the gate of MOSFET Q2 is connected to the anode of diode D3, and the cathode of diode D3 is connected to the wire leading from resistors R9 and R10; the sources of MOSFETs Q1 and Q2 are both grounded.

4. The single-fire wall dimmer according to claim 1, characterized in that, The adjustment dial of the rotary potentiometer is connected to the resistive element of the rotary potentiometer via a connecting rod. Capacitors C3 and C4 are connected in parallel between the variable resistance terminal of the sliding potentiometer and the variable resistance terminal of the rotary potentiometer.

5. The trailing edge phase single fire wall dimmer of claim 1 wherein, The emitter of transistor Q6 is also connected to the emitter of transistor Q5, and the collector of transistor Q5 and the emitter of transistor Q7 are both grounded.

6. The trailing edge phase single fire wall dimmer of claim 2 wherein, A capacitor C5 and a Zener diode D5 are connected in parallel across the two ends of resistor R14.

7. The post-phase single-fire wall dimmer according to claim 2, characterized in that, The emitter of transistor Q3 is also connected to the base of transistor Q4; the anode of the three-terminal regulator is grounded.

8. The single-fire wall dimmer according to claim 2, characterized in that, Resistor R4 is connected between the base and emitter of transistor Q4.

9. The back-cut single-fire wall dimmer according to claim 2, characterized in that, The grounding terminal of the low-dropout linear regulator is grounded.

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