Two-wire dimming circuit, PCB and lighting device

Abstract

The invention discloses a two-line dimming circuit, a PCB and a lighting device.The two-line dimming circuit comprises a main control unit, a communication unit, a logic gate unit and a full-bridge driving unit, the communication end of the communication unit is connected with the communication end of the main control unit, and the input end of the logic gate unit obtains three paths of PWM signals output by the main control unit; the color temperature signals are converted into two paths of color temperature driving signals; the output end of the logic gate unit is connected with the input end of the full-bridge driving unit, and the output end of the full-bridge driving unit is used for being connected with a lighting load; according to the two-line dimming circuit disclosed by the invention, the three paths of PWM signals output by the main control unit are converted into the two paths of color temperature driving signals with the dead zones through the logic gate unit, so that independent adjustment of double color temperatures is realized, and meanwhile, the dead zone control ensures that a time interval exists when the white light driving signals and the warm light driving signals are switched; the problem of signal interference in traditional two-wire dimming is solved, and the visible flicker phenomenon possibly caused by low-frequency PWM is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lighting driving, in particular to a two-wire dimming circuit, a PCB and a lighting device. BACKGROUND

[0002] LED lighting has been widely used in home, commercial lighting and other scenarios due to its advantages such as low energy consumption, long service life and adjustable brightness. Among them, dual-color LED light strips (white light + warm light) have become the mainstream choice because they support color temperature adjustment.

[0003] To simplify the installation and wiring process, a two-wire structure is adopted, that is, a dimming scheme that realizes power supply and signal transmission through only two wires, which has become a hot spot in the industry. However, under the limitation of the two-wire structure, the existing technology still has problems of line structure and dimming compatibility. Specifically, since the current two-wire dimming circuit mostly adopts power supply and signal multiplexing design, it is difficult to realize independent dimming of dual colors due to the bandwidth and anti-interference ability of two-wire transmission.

[0004] Currently, some schemes reduce the dimming frequency to below 50Hz to reduce signal interference, but this results in obvious flickering of the light strip brightness, especially in camera shooting scenarios.

[0005] Another part of the scheme uses analog signals (such as 0-10V voltage) to adjust brightness, which simplifies the signal processing process, but is easily affected by voltage attenuation in two-wire transmission, resulting in a decrease in dimming accuracy over long distances, and independent duty cycle control of white light and warm light cannot be achieved.

[0006] It can be seen that the existing technology needs to be improved and improved. SUMMARY

[0007] In view of the above shortcomings of the prior art, the purpose of the present application is to provide a two-wire dimming circuit that realizes independent duty cycle control of dual color temperature LEDs while maintaining the simplicity of the two-wire structure, solving the long-standing problem of wiring complexity and dimming performance contradiction in the industry.

[0008] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0009] A two-wire dimming circuit, comprising a master control unit, a communication unit, a logic gate unit and a full-bridge driving unit, the communication end of the communication unit is connected with the communication end of the master control unit, the output end of the master control unit is connected with the input end of the logic gate unit, and the logic gate unit is used to convert three-way PWM signals output by the master control unit into two-way color temperature driving signals; the output end of the logic gate unit is connected with the input end of the full-bridge driving unit, and the output end of the full-bridge driving unit is used to connect a lighting load.

[0010] The two-wire dimming circuit further comprises a power supply unit, an input end of the power supply unit is used for connecting an external power supply device, and output ends of the power supply unit are connected with a power supply end of the master control unit, a power supply end of the communication unit and a power supply end of the logic gate unit respectively.

[0011] The two-wire dimming circuit further comprises a power supply unit, an input end of the power supply unit is used for connecting an external power supply device, and output ends of the power supply unit are connected with a power supply end of the master control unit, a power supply end of the communication unit and a power supply end of the logic gate unit respectively.

[0012] The two-wire dimming circuit further comprises a power supply unit, an input end of the power supply unit is used for connecting an external power supply device, and output ends of the power supply unit are connected with a power supply end of the master control unit, a power supply end of the communication unit and a power supply end of the logic gate unit respectively.

[0013] The two-wire dimming circuit further comprises a power supply unit, an input end of the power supply unit is used for connecting an external power supply device, and output ends of the power supply unit are connected with a power supply end of the master control unit, a power supply end of the communication unit and a power supply end of the logic gate unit respectively.

[0014] The two-wire dimming circuit further comprises a power supply unit, an input end of the power supply unit is used for connecting an external power supply device, and output ends of the power supply unit are connected with a power supply end of the master control unit, a power supply end of the communication unit and a power supply end of the logic gate unit respectively.

[0015] The two-wire dimming circuit, the drive protection part includes a voltage stabilizing group and a signal amplification group, the input end of the voltage stabilizing group is used for connecting an external power supply device, the output end of the voltage stabilizing group is connected with the power supply end of the signal amplification group, the input end of the signal amplification group is connected with the pin 4 of the second control chip U2 respectively, the output end of the signal amplification group is connected with the input end of the drive part, and the signal amplification group is used for converting the white light drive signal and the warm light drive signal with a dead zone into two groups of complementary PWM signals with a dead zone, one group is the white light PWM signal with a dead zone, and the other group is the warm light PWM signal with a dead zone.

[0016] The two-wire dimming circuit, the drive part includes a first switch group, a second switch group, a third switch group and a fourth switch group, the input end of the first switch group and the input end of the fourth switch group are used for receiving the white light PWM signal with a dead zone, the input end of the second switch group and the input end of the third switch group are used for receiving the warm light PWM signal with a dead zone, and the output end of the first switch group, the output end of the second switch group, the output end of the third switch group and the output end of the fourth switch group are respectively used for connecting a lighting load.

[0017] The application also correspondingly provides a PCB plate, characterized by being printed with the two-wire dimming circuit of any one of the above.

[0018] The application also correspondingly provides a lighting device, which realizes working control by using the two-wire dimming circuit of any one of the above.

[0019] Beneficial effects:

[0020] The application provides a two-wire dimming circuit, which converts three-way PWM signals output by a master control unit into two-way color temperature drive signals with a dead zone through a logic gate unit, realizes independent adjustment of double color temperatures, effectively avoids the risk of short circuit of the switch tube in the full-bridge drive unit due to the dead zone design, and ensures that there is a time interval when the white light drive signal and the warm light drive signal are switched, thereby solving the signal interference problem in the traditional two-wire dimming and avoiding the visible flicker phenomenon caused by low-frequency PWM. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The circuit block diagram of the two-wire dimming circuit provided by the application is shown in the figure;

[0022] Figure 2 The circuit principle diagram of the master control unit and the logic gate unit provided by the application is shown in the figure;

[0023] Figure 3 The circuit principle diagram of the communication unit provided by the application is shown in the figure;

[0024] Figure 4 The circuit schematic diagram of the driving protection unit provided by the present application is shown in Figure 1.

[0025] Figure 5 The circuit schematic diagram of the driving unit provided by the present application is shown in Figure 2.

[0026] Figure 6 The circuit schematic diagram of the power supply unit provided by the present application is shown in Figure 3.

[0027] Main component symbol explanation: 1 - master control unit, 2 - communication unit, 3 - logic gate unit, 4 - full-bridge driving unit, 41 - driving protection unit, 42 - driving unit, 5 - power supply unit. DETAILED DESCRIPTION

[0028] The present application provides a two-wire dimming circuit, a PCB board and a lighting device. In order to make the purpose, technical solution and effect of the present application more clear and explicit, the present application is further described in detail below with reference to the accompanying drawings and examples.

[0029] In the description of the present application, it should be understood that the terms "mounting", "connection" and the like should be understood in a broad sense, and those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0030] Please refer to Figures 1 to 6 The present application provides a two-wire dimming circuit, which comprises a master control unit, a communication unit, a logic gate unit and a full-bridge driving unit. The communication end of the communication unit is connected with the communication end of the master control unit. The output end of the master control unit is connected with the input end of the logic gate unit. The logic gate unit is used for converting three-way PWM signals output by the master control unit into two-way color temperature driving signals. The output end of the logic gate unit is connected with the input end of the full-bridge driving unit. The output end of the full-bridge driving unit is used for connecting a lighting load.

[0031] In the present embodiment, external dimming instructions, such as color temperature or brightness signals sent by an APP, are received by the communication unit and converted into digital signals, and then transmitted to the master control unit. The master control unit generates three-way PWM signals according to the received digital dimming instructions. The logic gate unit performs logical operation on the three-way PWM signals and converts them into two-way color temperature driving signals. The full-bridge driving unit receives the two-way driving signals to control the conduction or turn-off of internal switching tubes, realizes the multiplexing function of power supply and signal transmission through double lines (fire wire and zero line or positive and negative power supply), uses the duty cycle change of the PWM signal to carry dimming information, and then completes the current on-off and brightness adjustment of the lighting load, effectively avoiding the need for additional wiring.

[0032] The present application discloses a two-wire dimming circuit, which converts three PWM signals output by a main control unit into two color temperature drive signals with dead zones through a logic gate unit. This circuit not only realizes the independent adjustment of dual color temperatures, that is, solves the problem that the traditional two-wire solution cannot take into account dual-color control; its dead zone design can also effectively avoid the risk of direct short circuit of the switch tube in the full-bridge drive unit; at the same time, the dead zone control ensures that there is a time interval between the white light and warm light drive signals when switching, which not only solves the signal interference problem in traditional two-wire dimming, but also avoids the visible flicker phenomenon that may be caused by low-frequency PWM.

[0033] Further, see Figure 1 and Figure 6 The two-wire dimming circuit also includes a power supply unit, the input end of the power supply unit is used to connect to an external power supply device, and the output end of the power supply unit is respectively connected to the power supply end of the main control unit, the power supply end of the communication unit and the power supply end of the logic gate unit.

[0034] In this embodiment, the external power supply device may use a 12V to 24V power adapter, and the power supply unit is used to provide a stable low voltage for the main control unit, the communication unit and the logic gate unit.

[0035] Further, see Figure 1 and Figure 6 The power supply unit includes a second connector J2, a first step-down unit and a second step-down unit. The input end of the first step-down unit is connected to the external power supply device through the second connector J2, the output end of the first step-down unit is connected to the input end of the second step-down unit, and the output end of the second step-down unit is respectively connected to the power supply end of the main control unit, the power supply end of the communication unit and the power supply end of the logic gate unit.

[0036] In this example, see Figure 6 , the external high voltage (12-24V) flows into the first step-down part through the second connector J2, is converted into a 10V intermediate voltage, and then input into the second step-down part; the second step-down part further converts the 10V voltage into a 3.3V low voltage to power the digital circuit (including main control, communication, and logic gates), realizing high and low voltage isolation, effectively avoiding the interference of high voltage noise on digital signals, ensuring the accuracy of logical operations, and ensuring the stability of PWM signal generation; specifically, the first step-down part adopts a non-isolated DC-DC chip, namely the third control chip U3, model LA1821; the pin VIN of the third control chip U3 is connected to pin 1 and pin 2 of the second connector J2, and its pin SW outputs a 10V voltage; the second step-down part adopts an LDO chip, namely the fourth control chip U4, model CJT1117B-3.3; the pin IN of the fourth control chip U4 is connected to the pin LDO of the third control chip U3, and its pin OUT outputs a 3.3V voltage.

[0037] In the embodiment, the combination of the non-isolated DC-DC chip and the LDO chip takes into account the efficiency and noise control; the non-isolated DC-DC chip is suitable for high-voltage to low-voltage conversion, and the LDO chip is suitable for low-voltage precision voltage stabilization, thereby guaranteeing the respective requirements of the digital circuit and the power circuit.

[0038] Further, referring to Figure 1 and Figure 3 , the communication unit includes a first connector J1 connected with the debugging end of the control unit for realizing firmware update of the control unit, and a wireless communication part whose communication end is connected with the communication end of the control unit, and which is used for receiving dimming instructions of an external application program and transmitting the digital signals converted from the dimming instructions to the control unit.

[0039] In the embodiment, referring to Figure 3 , the pin 3 and the pin 2 of the first connector J1 are connected with the debugging end of the master control unit, such as the pin ICE CLK RXD / pin ICE DAT TXD, for updating the firmware of the master control unit through a programmer; the external programmer transmits the firmware data to the master control unit through the first connector J1, and the current only flows between the debugging loop, i.e. the first connector J1 and the master control unit, without affecting other units; by setting the first connector J1, the circuit supports wireless debugging and firmware update without disassembling the shell, thereby reducing the later maintenance cost.

[0040] In the embodiment, the wireless communication part includes a ZigBee module ZSC; the pin RX and the pin TX of the wireless communication part are connected with the communication port of the master control unit, such as the pin UART0 TXD / pin UART0 RXD, and the antenna pin is externally connected with a PCB antenna; the dimming instructions of the external APP, such as “white light brightness 50%, warm light brightness 30%”, are transmitted to the wireless communication part through wireless signals based on the ZigBee protocol, and are converted into UART digital signals, high and low level signals, and then are transmitted to the master control unit through the pin TX and the pin RX, and the signal current is a weak signal current of μA level, thereby effectively avoiding interference with the power loop; the ZigBee communication has the advantages of transmission distance ≥50 meters and strong anti-interference ability, thereby solving the problem of attenuation of long-distance transmission of traditional two-wire analog signals and ensuring the dimming accuracy of the light strip of more than 10 meters.

[0041] Further, referring to Figure 1 and Figure 2, the logic gate unit is an AND gate circuit, comprising a second control chip U2; the control unit comprises a first control chip U1, a pin 15 of the first control chip U1 is used for outputting a total brightness reference signal, a pin 14 and a pin 13 of the first control chip U1 are respectively used for outputting two color separation control signals; the pin 15 and the pin 14 of the first control chip U1 are respectively connected with a pin 1 and a pin 2 of the second control chip U2, a pin 4 of the second control chip U2 is used for outputting a white light drive signal with a dead zone, the pin 13 of the first control chip U1 and the pin 4 of the second control chip U2 are respectively connected with input ends of the full-bridge drive circuit, and the pin 13 of the first control chip U1 is used for outputting a warm light drive signal.

[0042] In the embodiment, the first control chip U1 is of a model MS51FB9AE, the pin 15 of the first control chip U1 outputs the total brightness reference signal, the pin 14 outputs the white light color separation control signal, the pin 13 outputs the warm light color separation control signal, and the pin 13 is directly connected with the warm light signal input end of the full-bridge drive unit; when the total brightness reference signal is at a high level, the color separation control signal is allowed to take effect; when the total brightness reference signal is at a low level, the color separation control signal is shielded.

[0043] In the embodiment, the second control chip U2 is an SN74AHC1G08 AND gate, the pin 1 of the second control chip U2 is connected with the pin 15 of the first control chip U1, the pin 2 is connected with the pin 14 of the first control chip U1, and the pin 4 outputs the white light drive signal with a dead zone; the second control chip U2 combines the total brightness reference signal and the white light color separation control signal through logic AND operation: only when both of them are at a high level, the second control chip U2 outputs the white light drive signal with a high level and a dead zone; at the end of the white light drive signal with a dead zone, a low level dead zone is inserted by using the delay characteristic of the AND gate; the logic association of the total brightness reference and the color separation control is realized through the AND gate circuit, so that the sum of the brightness of the white light and the warm light does not exceed the total brightness, and the over-bright phenomenon is avoided; in addition, the dead zone design prevents the upper and lower bridge arm switches of the full-bridge drive unit from being simultaneously turned on from the hardware level, and effectively solves the short circuit burning problem caused by switching delay in the traditional scheme.

[0044] In the embodiment, the warm light color separation control signal and the white light color separation control signal are naturally complementary through internal programming of the first control chip U1, and are directly output to the full-bridge drive to form a complementary signal pair with the white light drive signal with a dead zone.

[0045] In the embodiment, the dead time interval is determined according to the turn-off delay time of the MOS tube, and the calculation formula is: dead time interval >= MOS tube turn-off delay time + circuit parasitic parameter delay; in the technical solution, the selected MOS tube type is NCEP60T12, the typical value of the turn-off delay is 50 ns, combined with the parasitic capacitance of the circuit, about 100 pF, the delay caused by the parasitic capacitance is about 20 ns, and the actual set dead time is 100 ns.

[0046] Further, please refer to Figure 1 , Figure 4 and Figure 5 , the full-bridge driving unit includes a driving protection part and a driving part, the input end of the driving protection part is connected with the pin 13 of the first control chip U1 and the pin 4 of the second control chip U2 respectively, the output end of the driving protection part is connected with the input end of the driving part, and the output end of the driving part is used for connecting the lighting load.

[0047] Further, please refer to Figure 1 , Figure 4 and Figure 5 , the driving protection part includes a voltage stabilizing group and a signal amplifying group, the input end of the voltage stabilizing group is used for connecting an external power supply device, the output end of the voltage stabilizing group is connected with the power supply end of the signal amplifying group, the input end of the signal amplifying group is connected with the pin 4 of the second control chip U2 respectively, the output end of the signal amplifying group is connected with the input end of the driving part, and the signal amplifying group is used for converting the white light driving signal and the warm light driving signal with dead time into two groups of complementary PWM signals with dead time, one group is the white light PWM signal with dead time, and the other group is the warm light PWM signal with dead time.

[0048] Further, please refer to Figure 1 , Figure 4 and Figure 5 , the driving part includes a first switch group, a second switch group, a third switch group and a fourth switch group, the input end of the first switch group and the input end of the fourth switch group are used for receiving the white light PWM signal with dead time, the input end of the second switch group and the input end of the third switch group are used for receiving the warm light PWM signal with dead time; the output end of the first switch group, the output end of the second switch group, the output end of the third switch group and the output end of the fourth switch group are respectively used for connecting the lighting load.

[0049] In the embodiment, please refer to Figure 4 and Figure 5The voltage stabilizing group comprises a fifth control chip U5, a seventh transistor Q7, an eighth transistor Q8 and a voltage stabilizing diode ZD1; a pin VIN of the fifth control chip U5 is used for connecting an external power supply device, the pin VIN of the fifth control chip U5 is also connected with a collector of the seventh transistor Q7, an emitter of the seventh transistor Q7 and a base and an emitter of the eighth transistor Q8 are respectively connected with a pin +15V of the sixth control chip U6, a base of the seventh transistor Q7, a collector of the eighth transistor Q8 and a pin VOUT of the fifth control chip U5 are connected with a negative electrode of the voltage stabilizing diode ZD1; the fifth control chip U5 is a DC-DC voltage reduction chip with a model of MP2307, an input end of which is connected with a high-voltage power supply of 12-24V and is used for outputting a stable 15V voltage to provide power support for the signal amplifying group; the seventh transistor Q7 and the eighth transistor Q8 are both NPN type transistors and together constitute a push-pull circuit, when the output current of the fifth control chip U5 is insufficient, the seventh transistor Q7 and the eighth transistor Q8 are turned on to supplement the current, so as to enhance the output driving capability of the fifth control chip U5; the voltage stabilizing diode ZD1 is used for clamping the output voltage to prevent overvoltage phenomenon, so as to protect the subsequent elements from being damaged and improve the circuit reliability.

[0050] In the embodiment, please refer to Figure 4 and Figure 5 The signal amplifying group comprises a sixth transistor Q6, a fifth transistor Q5 and a sixth control chip U6; the sixth control chip U6 is a full-bridge driving chip with a model of M615-4N and is responsible for receiving a PWM signal and outputting two complementary driving signals; the sixth transistor Q6 and the fifth transistor Q5 are NPN type and PNP type transistors respectively and together constitute a push-pull circuit and are used for amplifying the driving signal of the sixth control chip U6, so as to enhance the load capacity; the PWM signal output by the sixth control chip U6 drives the push-pull circuit, when the PWM signal is at a high level, the sixth transistor Q6 is turned on and the fifth transistor Q5 is turned off, and the signal is amplified to drive the switch group; when the PWM signal is at a low level, the fifth transistor Q5 is turned on and the sixth transistor Q6 is turned off, so as to realize push-pull driving and ensure the switch group to switch quickly; the internal logic of the sixth control chip U6 ensures that the two driving signals are strictly complementary, effectively solving the problem of bridge arm through caused by inconsistent delay of traditional discrete components; in addition, the sixth control chip U6 supports a PWM frequency of 20kHz to 100kHz, which, in cooperation with the push-pull circuit, can avoid high-frequency oscillation, so as to solve the EMI interference problem caused by traditional transistor driving.

[0051] In the embodiment, please refer to Figure 4 and Figure 5The first switch group comprises a first field effect tube Q1, a first diode D1 and a fourth resistor R4, the second switch group comprises a second field effect tube Q2, a second diode D2 and a sixth resistor R6, the third switch group comprises a third field effect tube Q3, a third diode D3 and a tenth resistor R10, and the fourth switch group comprises a fourth field effect tube Q4, a fourth diode D4 and a fifteenth resistor R15; all the four field effect tubes are N-channel MOS tubes, which are used as switch elements to control load current, and their bidirectional conduction characteristics are adapted to the complementary drive logic of the sixth control chip U6, thereby effectively solving the problem that the traditional diode rectification scheme cannot realize bidirectional control; in addition, all the four diodes are freewheeling diodes, which provide a discharge loop for inductive current when the load is powered off, thereby solving the problem of voltage spikes generated by inductive load and avoiding damage to MOS tubes caused by voltage spikes.

[0052] In actual operation of the driving part, for the warm light circuit:

[0053] Conduction phase: when the warm light control signal with dead zone is at a high level, the sixth control chip U6 outputs a drive signal, causing the voltage of the G pole of the first field effect tube Q1 and the G pole of the fourth field effect tube Q4 to rise, and then causing the D-S pole of the first field effect tube Q1 and the D-S pole of the fourth field effect tube Q4 to be conductive; at this time, the current path is: 12V positive pole→D-S pole of the first field effect tube Q1→warm light load→D-S pole of the fourth field effect tube Q4→GND.

[0054] Turn-off phase: when the warm light control signal with dead zone becomes a low level, the first field effect tube Q1 and the fourth field effect tube Q4 are cut off, and the energy stored in the load inductor is discharged through the first diode D1 and the fourth diode D4; at this time, the current path is: warm light load→first diode D1→12V positive pole→fourth diode D4→warm light load.

[0055] For the white light circuit:

[0056] Conduction phase: when the white light control signal with dead zone is at a high level, the sixth control chip U6 outputs a drive signal, causing the voltage of the G pole of the second field effect tube Q2 and the G pole of the third field effect tube Q3 to rise, and then causing the D-S pole of the second field effect tube Q2 and the D-S pole of the third field effect tube Q3 to be conductive; at this time, the current path is: 12V positive pole→D-S pole of the third field effect tube Q3→white light load→D-S pole of the second field effect tube Q2→GND.

[0057] Turn-off phase: when the white light control signal with dead zone becomes a low level, the second field effect tube Q2 and the third field effect tube Q3 are cut off, and the energy stored in the load inductor is discharged through the third diode D3 and the second diode D2; at this time, the current path is: white light load→third diode D3→12V positive pole→second diode D2→white light load.

[0058] In the embodiment, for the white light signal, since the white light brightness and the warm light brightness need to be cooperatively controlled in the dimming system to achieve different color temperatures and total brightness effects, the white light signal needs to be logically operated with the total brightness reference signal; by using an AND gate circuit to perform an AND operation on the white light color separation signal and the total brightness reference signal, the effective control part of the white light can be accurately retained, and a dead zone is inserted at the end of the signal; in this way, according to the total brightness demand and the proportion of the white light therein, the output of the white light can be accurately controlled, while the dead zone protection is realized, avoiding the short circuit caused by the simultaneous conduction of the related MOS tubes in the full-bridge circuit;

[0059] For the warm light signal, the warm light signal and the white light signal are complementary to each other, that is, one is high level and the other is low level; by using the characteristics of the push-pull circuit, when the warm light signal is performing level conversion and driving enhancement, the conduction / cutoff delay of the triode in the push-pull circuit naturally forms a dead zone; and under the complementary logic with the white light signal, combined with the conduction condition of the push-pull circuit, that is, the condition that the MCU output white light control signal with a dead zone is high level and the enable signal of the full-bridge module is an effective level, the control of the warm light loop can be effectively realized, without additional logic processing through the AND gate circuit to generate a dead zone.

[0060] The application also correspondingly provides a PCB board, characterized in that the PCB board is printed with the two-wire dimming circuit according to any one of the above.

[0061] The application also correspondingly provides a lighting device, which realizes working control by using the two-wire dimming circuit according to any one of the above.

[0062] It can be understood that, for those skilled in the art, equivalent replacements or changes can be made according to the technical solutions and the inventive concept of the application, and all these changes or replacements shall belong to the protection scope of the application.

Claims

1. A two-wire dimming circuit, characterized by, The application relates to a control unit for a lighting load, comprising a main control unit, a communication unit, a logic gate unit and a full-bridge driving unit, wherein the communication end of the communication unit is connected with the communication end of the main control unit, the output end of the main control unit is connected with the input end of the logic gate unit, the logic gate unit is used for converting three-way PWM signals output by the main control unit into two-way color temperature driving signals, the output end of the logic gate unit is connected with the input end of the full-bridge driving unit, and the output end of the full-bridge driving unit is used for connecting the lighting load.

2. The two-wire dimming circuit of claim 1, wherein, The application further comprises a power supply unit, the input end of the power supply unit is used for connecting an external power supply device, and the output end of the power supply unit is connected with the power supply end of the main control unit, the power supply end of the communication unit and the power supply end of the logic gate unit respectively.

3. The two-wire dimming circuit of claim 2, wherein, The power supply unit comprises a second plug J2, a first voltage reduction part and a second voltage reduction part, the input end of the first voltage reduction part is connected with the external power supply device through the second plug J2, the output end of the first voltage reduction part is connected with the input end of the second voltage reduction part, and the output end of the second voltage reduction part is connected with the power supply end of the main control unit, the power supply end of the communication unit and the power supply end of the logic gate unit respectively.

4. The two-wire dimming circuit of claim 1, wherein, The communication unit comprises a first plug J1 and a wireless communication part, the first plug J1 is connected with the debugging end of the control unit, is used for realizing firmware updating of the control unit, the communication end of the wireless communication part is connected with the communication end of the control unit, the wireless communication part is used for receiving the instruction of an external application program, converting the digital signal and then transmitting the digital signal to the control unit.

5. The two-wire dimming circuit of claim 1, wherein, The logic gate unit is an AND gate circuit and comprises a second control chip U2; the control unit comprises a first control chip U1, the pin 15 of the first control chip U1 is used for outputting a total brightness reference signal, the pin 14 and the pin 13 of the first control chip U1 are used for outputting two-way color separation control signals respectively, the pin 15 and the pin 14 of the first control chip U1 are connected with the pin 1 and the pin 2 of the second control chip U2 respectively, the pin 4 of the second control chip U2 is used for outputting a white light driving signal with a dead zone, the pin 13 of the first control chip U1 and the pin 4 of the second control chip U2 are connected with the input end of the full-bridge driving circuit respectively, and the pin 13 of the first control chip U1 is used for outputting a warm light driving signal.

6. The two-wire dimming circuit of claim 5, wherein, The full-bridge driving unit comprises a driving protection part and a driving part, the input end of the driving protection part is connected with the pin 13 of the first control chip U1 and the pin 4 of the second control chip U2 respectively, the output end of the driving protection part is connected with the input end of the driving part, and the output end of the driving part is used for connecting the lighting load.

7. The two-wire dimming circuit of claim 6, wherein, The driving protection part comprises a voltage stabilizing group and a signal amplification group, the input end of the voltage stabilizing group is used for connecting an external power supply device, the output end of the voltage stabilizing group is connected with the power supply end of the signal amplification group, the input end of the signal amplification group is respectively connected with the pin 4 of the second control chip U2, the output end of the signal amplification group is connected with the input end of the driving part, and the signal amplification group is used for converting the white light driving signal and the warm light driving signal with dead zones into two groups of complementary PWM signals with dead zones, one group is the white light PWM signal with dead zones, and the other group is the warm light PWM signal with dead zones.

8. The two-wire dimming circuit of claim 7, wherein, The driving part comprises a first switch group, a second switch group, a third switch group and a fourth switch group, the input end of the first switch group and the input end of the fourth switch group are used for receiving the white light PWM signal with dead zones, and the input end of the second switch group and the input end of the third switch group are used for receiving the warm light PWM signal with dead zones. The output end of the first switch group, the output end of the second switch group, the output end of the third switch group and the output end of the fourth switch group are respectively used for connecting a lighting load.

9. A PCB board characterized by, The PCB is printed with the two-wire dimming circuit according to any one of claims 1-8.

10. An illumination device, characterized by The lighting device is realized working control by using the two-wire dimming circuit according to any one of claims 1-8.

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