LED Dimming Circuit, Dimmer and Lighting Device

Abstract

Embodiments of the present invention disclose an LED dimming circuit, a dimmer, and a lighting device. The LED dimming circuit includes: an AC-DC conversion module for converting a first AC voltage into a first DC voltage, where the first AC voltage is an input AC voltage; a DC-DC conversion module for converting the first DC voltage into a second DC voltage, where the magnitude of the second DC voltage matches the specified brightness of the LED; and a dimming instruction transmission module for coupling a dimming instruction and generating a control signal for controlling the DC-DC conversion module according to the dimming instruction to transmit the dimming instruction. The LED dimming circuit, dimmer, and lighting device provided by the embodiments of the present invention can achieve precise, efficient, and real-time dimming of multiple LED lighting devices, reduce the signal demodulation steps, lower the system hardware cost and the difficulty of implementing the solution, and reduce the signal distortion degree.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of lighting technologies, and in particular, to an LED dimming circuit, a dimmer, and a lighting device. Background Art

[0002] With the continuous development of light-emitting diode (LED) lighting technologies, the market demand for LED lighting devices has become increasingly strong. As one of the representative functions of dynamic control of LED lighting, the optimization and upgrade of the dimming function have become the core elements of the research on intelligent and healthy lighting technologies.

[0003] Generally speaking, in the actual engineering application process, LED lighting devices can be divided into three categories, namely replacement type, retrofit type, and new construction type. Usually, when upgrading the dimming function of replacement type or retrofit type LED lighting devices, it is necessary to replace the original lighting device to match the existing dimmer. Therefore, as Figures 1 - 3 shown, existing dimmers can be classified into the following three methods according to their working principles:

[0004] The first is the thyristor dimming method. As Figure 1 shown, this method adjusts the effective value of the input voltage, and the LED lighting device realizes the dimming effect according to the power signal generated by the dimmer; as Figure 2 shown, the second dimming method is to transmit the dimming signal to the signal demodulation circuit inside the LED lighting device through the dimmer. The signal demodulation circuit adjusts the output voltage or current according to the received dimming signal, and then realizes the dimming function; as Figure 3 shown, the third dimming method is to connect a dimmer that can synthesize the power signal and the dimming signal in the original circuit, and transmit the synthesized dimming signal to the LED lighting device through the dimmer. After being analyzed by the signal demodulation circuit inside the device, the dimming function is realized.

[0005] For the thyristor dimming method, this method will cause voltage waveform distortion and reduce the lighting efficiency; for the second dimming method, in the scenario of multiple LED lighting devices, each LED lighting device needs to be equipped with a signal line to receive the dimming signal accordingly, so it will increase the engineering complexity of the LED lighting device and increase the engineering construction difficulty of the lighting system; the third dimming method has special requirements for the LED lighting device and needs to replace the LED lighting device to realize the dimming function. Based on this, this method not only increases the engineering cost but also abandons the original normally working LED lighting device, resulting in resource waste. In addition, during the installation process, existing LED lighting devices using the above three dimming methods are also prone to electric shock risks caused by single-end power-on and conduction at the other end, seriously threatening the lives of installation personnel. Summary of the Invention

[0006] An embodiment of the present invention provides an LED dimming circuit, a dimmer, and a lighting device, which are used to reduce system costs, reduce signal distortion, and enhance system compatibility while accurately and efficiently completing real-time dimming.

[0007] In a first aspect, an embodiment of the present invention provides an LED dimming circuit, including:

[0008] An AC-DC conversion module for converting a first AC voltage into a first DC voltage; wherein, the first AC voltage is an input AC voltage;

[0009] A DC-DC conversion module for converting the first DC voltage into a second DC voltage; wherein, the magnitude of the second DC voltage matches the specified brightness of the LED.

[0010] A dimming instruction transmission module for coupling a dimming instruction, generating a control signal for controlling the DC-DC conversion module according to the dimming instruction, and transmitting the dimming instruction.

[0011] Optionally, the first AC voltage is an adjustable voltage; correspondingly, the first DC voltage is an adjustable voltage; the voltage value of the first DC voltage corresponds one-to-one with the voltage value of the first AC voltage.

[0012] Optionally, the DC-DC conversion module includes:

[0013] A first transformer, the first transformer includes a primary winding and a secondary winding, the primary winding is used to connect to the first DC voltage, and the secondary winding is used to output the second DC voltage;

[0014] A feedback unit, the feedback unit is connected in series between the primary winding and a first ground terminal, and the feedback unit is used to receive the dimming instruction and control the on-off between the primary winding and the first ground terminal accordingly.

[0015] Optionally, it further includes a first optocoupler; the feedback unit and the dimming instruction transmission module transmit the dimming instruction through the first optocoupler.

[0016] Optionally, the dimming instruction transmission module includes:

[0017] A first comparator, a first input terminal of the first comparator is connected to the dimming instruction, and a second input terminal of the first comparator is connected to a comparison voltage signal;

[0018] The light emitter in the first optocoupler is connected in series between the output terminal of the first comparator and a first power supply terminal.

[0019] Optionally, the feedback unit includes:

[0020] A feedback control chip, which includes a feedback pin and a gate drive output pin;

[0021] A first transistor, which is connected in series between the primary side winding and the first ground terminal, and the gate of the first transistor is electrically connected to the gate drive output pin;

[0022] The light receiver in the first optocoupler is connected in series between the feedback pin and the first ground terminal.

[0023] Optionally, the DC-DC conversion module further includes:

[0024] A first inductor, which is connected in series between the AC-DC conversion module and the primary side winding; wherein, the first inductor is electrically connected to the first end of the primary side winding;

[0025] A first resistor, which is connected in parallel with the first inductor;

[0026] A first capacitor, the first end of which is electrically connected to the first end of the first resistor, and the second end of which is electrically connected to the first ground terminal;

[0027] A second capacitor, the first end of which is electrically connected to the second end of the first resistor, and the second end of which is electrically connected to the first ground terminal;

[0028] A first varistor, which is connected in parallel with the second capacitor;

[0029] A third capacitor, the first end of which is electrically connected to the first end of the second capacitor;

[0030] A first diode, the cathode of which is electrically connected to the second end of the third capacitor, and the anode of which is electrically connected to the second end of the primary side winding;

[0031] A second resistor, which is connected in parallel with the third capacitor.

[0032] Optionally, the DC-DC conversion module further includes:

[0033] A third resistor, the first end of which is electrically connected to the first end of the secondary side winding;

[0034] A fourth capacitor, the first end of which is electrically connected to the second end of the third resistor, and the second end of which serves as the first output terminal of the dimming circuit;

[0035] A second diode, a first end of the second diode is electrically connected to a first end of the secondary side winding, and a second end of the second diode is electrically connected to a first output end of the dimming circuit;

[0036] A fifth capacitor, a first end of the fifth capacitor is electrically connected to the first output end of the dimming circuit, a second end of the fifth capacitor is electrically connected to a second end of the secondary side winding and is electrically connected to a second grounding end;

[0037] A fourth resistor, the fourth resistor is connected in parallel with the fifth capacitor;

[0038] A fifth resistor, a first end of the fifth resistor is electrically connected to the second end of the secondary side winding, and a second end of the fifth resistor is electrically connected to a second output end of the dimming circuit;

[0039] A third diode, an anode of the third diode is electrically connected to the second output end of the dimming circuit, and a cathode of the third diode is electrically connected to the second end of the secondary side winding.

[0040] Optionally, the DC-DC conversion module includes:

[0041] A second transformer, the second transformer includes a primary side winding and two secondary side windings connected in series, a connection point of the two secondary side windings is defined as an output node, and two ends of the two secondary side windings different from the output node are respectively a first end and a second end;

[0042] A first switch unit, the first switch unit is connected in series between an output end of the AC-DC conversion module and the primary side winding;

[0043] A second switch unit, the second switch unit is connected in parallel with the primary side winding;

[0044] A first control unit, the first control unit is configured to receive the dimming instruction and control the on / off of the first switch unit and the second switch unit accordingly;

[0045] A third switch unit, the third switch unit is connected in series between the first end of the secondary side winding and a first voltage end;

[0046] A fourth switch unit, the fourth switch unit is connected in series between the second end of the secondary side winding and a second voltage end;

[0047] A second control unit, the second control unit is configured to control the on / off of the third switch unit and the fourth switch unit;

[0048] Wherein, the output node is electrically connected to the first output terminal of the dimming circuit, and the second voltage terminal is electrically connected to the second output terminal of the dimming circuit.

[0049] Optionally, it further includes: a second optocoupler; the first control unit and the dimming instruction transmission module transmit the dimming instruction through the second optocoupler.

[0050] Optionally, the dimming instruction transmission module includes:

[0051] A third comparator, the first input terminal of the third comparator accesses the dimming instruction, and the second input terminal of the third comparator accesses a comparison voltage signal;

[0052] A fourth comparator, the first terminal of the fourth comparator is electrically connected to the second ground terminal, and the second terminal of the fourth comparator accesses the comparison voltage signal;

[0053] The light emitter in the second optocoupler is serially connected between the output terminal of the third comparator and the first power supply terminal; the output terminal of the fourth comparator is electrically connected to the output terminal of the third comparator.

[0054] Optionally, the first control unit includes:

[0055] A resonant control chip, the resonant control chip includes a resonant control pin, a first gate drive output pin, and a second gate drive output pin;

[0056] The light receiver in the second optocoupler is serially connected between the resonant control pin and the first ground terminal; the first gate drive output pin is electrically connected to the first switch unit, and the second gate drive output pin is electrically connected to the second switch unit.

[0057] Optionally, the second control unit includes:

[0058] An LLC synchronous rectifier, the LLC synchronous rectifier includes a first voltage pin, a second voltage pin, a third voltage pin, a fourth voltage pin, a third gate drive pin, and a fourth gate drive pin;

[0059] The first voltage pin accesses a second voltage signal, the second voltage pin is electrically connected to the first voltage terminal and is also electrically connected to the second voltage terminal; the third voltage pin is electrically connected to the first end of the secondary side winding, the fourth voltage pin is electrically connected to the second end of the secondary side winding; the third gate drive pin is electrically connected to the third switch unit, and the fourth gate drive pin is electrically connected to the fourth switch unit.

[0060] Optionally, the DC-DC conversion module further includes:

[0061] A second inductor, which is connected in series between the first switching unit and the primary side winding.

[0062] Optionally, the DC-DC conversion module further includes:

[0063] A sixth resistor, which is connected in series between the third switching unit and the second output terminal of the dimming circuit;

[0064] A seventh resistor, the first end of which is electrically connected to the first output terminal of the dimming circuit, and the second end of which is electrically connected to the third switching unit;

[0065] A sixth capacitor, which is connected in parallel with the seventh resistor.

[0066] Optionally, it further includes:

[0067] A current detection module, which is electrically connected to the second output terminal of the dimming circuit, and is used for detecting the current at the second output terminal.

[0068] Optionally, the current detection module includes:

[0069] A fifth comparator, which includes a first input terminal, a second input terminal and an output terminal;

[0070] An eighth resistor, the first end of which is electrically connected to the second output terminal of the dimming circuit;

[0071] A ninth resistor, the first end of which is electrically connected to the second end of the eighth resistor, and the second end of which is electrically connected to the first input terminal of the fifth comparator;

[0072] A tenth resistor, the first end of which is electrically connected to the second grounding terminal, and the second end of which is electrically connected to the first input terminal of the fifth comparator;

[0073] An eleventh resistor, the first end of which is electrically connected to the second grounding terminal;

[0074] A twelfth resistor, the first end of which is electrically connected to the second end of the eleventh resistor; the second end of the twelfth resistor is electrically connected to the second input terminal of the fifth comparator;

[0075] A thirteenth resistor, the first end of which is electrically connected to the second end of the twelfth resistor; the second end of the thirteenth resistor is electrically connected to the output terminal of the fifth comparator;

[0076] The seventh capacitor, a first end of the seventh capacitor is electrically connected to a first end of the tenth resistor, and a second end of the seventh capacitor is electrically connected to a first end of the twelfth resistor;

[0077] The fourteenth resistor, a first end of the fourteenth resistor is electrically connected to an output end of the fifth comparator, and a second end of the fourteenth resistor serves as an output end of the current detection module;

[0078] The eighth capacitor, a first end of the eighth capacitor is electrically connected to the second end of the fourteenth resistor, and a second end of the eighth capacitor is electrically connected to the second grounding end.

[0079] Optionally, the current detection module includes:

[0080] The sixth comparator, the sixth comparator includes a first input end, a second input end and an output end;

[0081] The fifteenth resistor, a first end of the fifteenth resistor is electrically connected to a second output end of the dimming circuit, and a second end of the fifteenth resistor is electrically connected to the first input end of the sixth comparator;

[0082] The ninth capacitor, a first end of the ninth capacitor is electrically connected to the first input end of the sixth comparator, and a second end of the ninth capacitor is electrically connected to the second input end of the sixth comparator;

[0083] The sixteenth resistor, a first end of the sixteenth resistor is connected to a comparison voltage signal, and a second end of the sixteenth resistor is electrically connected to the second input end of the sixth comparator;

[0084] The seventeenth resistor, a first end of the seventeenth resistor is electrically connected to the output end of the sixth comparator, and a second end of the seventeenth resistor serves as an output end of the current detection module;

[0085] The tenth capacitor, a first end of the tenth capacitor is electrically connected to the output end of the current detection module, and a second end of the tenth capacitor is electrically connected to the second output end of the dimming circuit.

[0086] Optionally, the AC-DC conversion module includes:

[0087] An electromagnetic compatibility unit, configured to resist electromagnetic interference and transmit the filtered first AC voltage to a subsequent circuit;

[0088] A rectifier bridge, configured to convert the filtered first AC voltage into the first DC voltage.

[0089] Optionally, it further includes:

[0090] A power factor correction module is connected between the AC-DC conversion module and the DC-DC conversion module; the power factor correction module is used to perform power factor correction on the first DC voltage and then transmit it to the DC-DC conversion module.

[0091] Optionally, it further includes:

[0092] A DC-AC conversion module is used to invert the second DC voltage into a second AC voltage, and the second AC voltage serves as the output voltage of the LED dimming circuit.

[0093] Optionally, the DC-AC conversion module includes:

[0094] An inverter bridge unit is used to couple the inverter drive signal and invert the second DC voltage into the second AC voltage;

[0095] An inverter drive unit is used to couple the control signal and convert it into the inverter drive signal that can be used to drive the inverter bridge unit to work.

[0096] Optionally, the inverter bridge unit includes:

[0097] A first bridge arm, the first bridge arm includes a first upper bridge arm and a first lower bridge arm, and the first upper bridge arm and the first lower bridge arm are used to couple the inverter drive signal and conduct alternately;

[0098] A second bridge arm, the second bridge arm includes a second upper bridge arm and a second lower bridge arm, and the second upper bridge arm and the second lower bridge arm are used to couple the inverter drive signal and conduct alternately.

[0099] Optionally, the inverter drive unit includes:

[0100] A first half-bridge drive circuit is used to couple the control signal to generate a first upper bridge arm drive signal and a first lower bridge arm drive signal, the first upper bridge arm drive signal is used to drive the first upper bridge arm, and the first lower bridge arm drive signal is used to drive the first lower bridge arm;

[0101] A second half-bridge drive circuit is used to couple the control signal to generate a second upper bridge arm drive signal and a second lower bridge arm drive signal, the second upper bridge arm drive signal is used to drive the second upper bridge arm, and the second lower bridge arm drive signal is used to drive the second lower bridge arm.

[0102] In a second aspect, an embodiment of the present invention further provides an LED dimmer, including the dimming circuit provided in any embodiment of the present invention.

[0103] In a third aspect, an embodiment of the present invention further provides an LED lighting device, including the LED dimmer provided in any embodiment of the present invention.

[0104] For the technical solution provided by the embodiment of the present invention, first, by setting an AC-DC conversion module, the input first AC voltage is converted into a first DC voltage for the dimming command to be coupled; second, by setting a dimming command transfer module, the dimming command is coupled and a control signal capable of transmitting the dimming command is generated; finally, by setting a DC-DC conversion module, according to the control signal, the first DC voltage is converted into a second DC voltage that can match the specified brightness of the LED. It can be seen that, compared with the prior art, the embodiment of the present invention fills the defect that the thyristor dimming method will generate voltage waveform distortion and reduce the lighting efficiency; solves the problems of the prior dimming method of adjusting the output voltage or current based on the dimming signal through the signal demodulation circuit, which requires multiple signal lines, the connection lines are redundant, and the engineering implementation is difficult; overcomes the drawback that the prior dimming method of adjusting the output voltage or current based on the synthesized dimming signal through the signal demodulation circuit requires discarding the original normally working LED lighting device, increasing the engineering cost and causing resource waste. In summary, the embodiment of the present invention not only realizes the accurate, efficient and real-time dimming effect of the LED, but also reduces the signal demodulation steps, which is beneficial to reducing the system hardware cost and the difficulty of scheme implementation, and reducing the distortion of the system signal. In addition, the embodiment of the present invention can be compatible with multiple different types of retrofit LED lighting devices, that is, Type B lighting devices, without additional modification to the LED lighting device. Description of the Drawings

[0105] Figure 1 is a schematic structural diagram of an LED dimming circuit in the prior art;

[0106] Figure 2 is a schematic structural diagram of another LED dimming circuit in the prior art;

[0107] Figure 3 is a schematic structural diagram of yet another LED dimming circuit in the prior art;

[0108] Figure 4 is a schematic structural diagram of an LED dimming circuit provided by an embodiment of the present invention;

[0109] Figure 5 is a circuit diagram of a DC-DC conversion module provided by an embodiment of the present invention;

[0110] Figure 6 is a circuit diagram of a dimming command transfer module provided by an embodiment of the present invention;

[0111] Figure 7 is a circuit diagram of a current detection module provided by an embodiment of the present invention;

[0112] Figure 8It is the circuit diagram of an AC-DC conversion module provided by an embodiment of the present invention;

[0113] Figure 9 It is the circuit diagram of another DC-DC conversion module provided by an embodiment of the present invention;

[0114] Figure 10 It is the circuit diagram of another dimming instruction transmission module provided by an embodiment of the present invention;

[0115] Figure 11 It is the circuit diagram of another current detection module provided by an embodiment of the present invention;

[0116] Figure 12 It is the circuit diagram of another AC-DC conversion module provided by an embodiment of the present invention;

[0117] Figure 13 It is the circuit diagram of a power factor correction module provided by an embodiment of the present invention;

[0118] Figure 14 It is the structural schematic diagram of another LED dimming circuit provided by an embodiment of the present invention;

[0119] Figure 15 It is the structural schematic diagram of a DC-AC conversion module provided by an embodiment of the present invention. Specific Embodiments

[0120] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the accompanying drawings.

[0121] Figure 4 It is the structural schematic diagram of an LED dimming circuit provided by an embodiment of the present invention. As Figure 4 shown, the LED dimming circuit includes: an AC-DC conversion module 101, a dimming instruction transmission module 102, and a DC-DC conversion module 103.

[0122] The AC-DC conversion module 101 is used to convert the first AC voltage AC1 into the first DC voltage DC1; wherein, the first AC voltage AC1 is the input AC voltage. The dimming instruction transmission module 102 is used to couple the dimming instruction and generate a control signal for controlling the DC-DC conversion module 103 according to the dimming instruction to transmit the dimming instruction. The DC-DC conversion module 103 is used to convert the first DC voltage DC1 into the second DC voltage DC2; wherein, the voltage magnitude of the second DC voltage DC2 matches the specified brightness of the LED.

[0123] Among them, the AC-DC conversion module 101 includes an AC voltage input terminal and a first DC voltage output terminal. The AC voltage input terminal is connected to a first AC voltage AC1, and the first DC voltage output terminal outputs a first DC voltage DC1. Optionally, the first AC voltage AC1 is an adjustable voltage; correspondingly, the first DC voltage DC1 is an adjustable voltage; the voltage value of the first DC voltage DC1 corresponds one-to-one to the voltage value of the first AC voltage AC1. It can be understood that the effective voltage value range of the first AC voltage AC1 can be any voltage value within the range of [120, 277], and the voltage value range of the first DC voltage DC1 can be any voltage value within the range of [150, 400]. The embodiments of the present invention do not limit this. In addition, the frequency parameter of the first AC voltage AC1 can be 50 Hz, or can be 60 Hz.

[0124] It can be understood that the AC-DC conversion module 101 can be any rectification circuit. The embodiments of the present invention do not limit this. For example, it can be an uncontrolled rectification circuit, or a semi-controlled rectification circuit, or a fully controlled rectification circuit. The conversion object of the AC-DC conversion module 101 can be any single-phase AC power signal generated by an external AC power source, such as the mains power.

[0125] It is known that the dimming instruction transmission module 102 includes a dimming instruction input terminal and a control signal output terminal. The dimming instruction input terminal is connected to a dimming instruction, and the control signal output terminal outputs a control signal. In addition, the DC-DC conversion module 103 includes a control signal input terminal, a first DC voltage input terminal, and a second DC voltage output terminal. The first DC voltage input terminal is connected to the first DC voltage DC1, the control signal input terminal is connected to the control signal, and the second DC voltage output terminal outputs a second DC voltage DC2. It can be understood that the first DC voltage input terminal is electrically connected to the first DC voltage output terminal, and the control signal input terminal is electrically connected to the control signal output terminal. The signal types transmitted between the control signal input terminal and the control signal output terminal, and between the first DC voltage input terminal and the first DC voltage output terminal can be level signals. The embodiments of the present invention do not limit this. It is known that the second DC voltage DC2 is an adjustable voltage. Exemplarily, the voltage value range of the second DC voltage DC2 can be any voltage value within the range of [40, 125]; the signal types of the control signal and the dimming instruction can be digital signals; the transmission mode of the dimming instruction can be wired transmission, or can be wireless transmission; the number system of the control signal and the dimming instruction can be binary.

[0126] It can be understood that the voltage magnitude of the second DC voltage DC2 matching the specified brightness of the LED means that the second DC voltage DC2 with different voltage magnitudes corresponds to different brightnesses of the same LED. It is known that within the inherent operating voltage range of the LED, the larger the second DC voltage DC2, the brighter the LED. In addition, the basic principle circuit of the DC-DC conversion module 103 can be any type of chopper circuit. Exemplarily, the basic principle circuit of the DC-DC conversion module 103 can be a Buck circuit, or it can be a Boost circuit, or it can be a Buck-Boost circuit, or it can be a Cuk circuit, etc.

[0127] In the technical solution of this embodiment, first, by setting the AC-DC conversion module 101, the input first AC voltage AC1 is converted into the first DC voltage DC1 to which the dimming instruction is to be coupled; second, by setting the dimming instruction transfer module 102, the dimming instruction is coupled and a control signal capable of transmitting the dimming instruction is generated; finally, by setting the DC-DC conversion module 103, according to the control signal, the first DC voltage DC1 is converted into the second DC voltage DC2 that can match the specified brightness of the LED. Thus, compared with the prior art, the embodiment of the present invention fills the defect that the thyristor dimming method will generate voltage waveform distortion and reduce the lighting efficiency; solves the problems of the prior dimming method of adjusting the output voltage or current based on the dimming signal through the signal demodulation circuit, which requires multiple signal lines, the connection lines are redundant, and the engineering implementation is difficult; overcomes the disadvantages of the prior dimming method of adjusting the output voltage or current based on the synthesized dimming signal through the signal demodulation circuit, which requires discarding the original normally operating LED lighting device, increasing the engineering cost and causing resource waste. In summary, the embodiment of the present invention not only realizes the effects of accurate, efficient and real-time dimming of the LED, but also reduces the signal demodulation steps, which is beneficial to reducing the system hardware cost and the difficulty of scheme implementation, and reducing the distortion of the system signal. In addition, the embodiment of the present invention can be compatible with multiple different types of retrofit LED lighting devices, that is, TypeB lighting devices, without additional modification to the LED lighting device.

[0128] On the basis of the above embodiments, Figure 5 is a circuit diagram of a DC-DC conversion module provided by an embodiment of the present invention. As Figure 5 shown, optionally, the DC-DC conversion module 103 includes a first transformer T1 and a feedback unit 210. The first transformer T1 includes a primary winding and a secondary winding. The primary winding is used to connect to the first DC voltage DC1, and the secondary winding is used to output the second DC voltage DC2. The feedback unit 210 is connected in series between the primary winding and the first ground terminal. The feedback unit 210 is used to receive the dimming instruction and control the on-off between the primary winding and the first ground terminal accordingly.

[0129] Among them, the DC-DC conversion module 103 converts the first DC voltage DC1 into a second DC voltage DC2 through the first transformer T1. It can be known that the primary side winding of the first transformer T1, the feedback unit 210, and the first grounding end can form a closed loop. When the feedback unit 210 receives a dimming instruction, the feedback unit 210 controls the on / off between the primary side winding and the first grounding end, and thus the controllable adjustment of the second DC voltage DC2 can be realized. It can be understood that the feedback unit 210 can, but is not limited to, control the on / off frequency or duty cycle between the primary side winding and the first grounding end to realize the controllable adjustment of the second DC voltage DC2.

[0130] Based on the above embodiments, Figure 6 is a circuit diagram of a dimming instruction transmission module provided by an embodiment of the present invention. As Figure 6 shown, optionally, the dimming instruction transmission module 102 includes a first comparator U2B. The first input terminal of the first comparator U2B is connected to the dimming instruction, the second input terminal of the first comparator U2B is connected to a comparison voltage signal, and the light emitter IC1A in the first optocoupler is connected in series between the output terminal of the first comparator U2B and the first power supply terminal.

[0131] Among them, the first comparator U2B is used to output a level signal according to the dimming instruction and the comparison voltage signal; the comparison voltage signal can be a voltage signal of any magnitude. It can be known that when the dimming instruction and the comparison voltage signal are inconsistent, this level signal can cause the light emitter IC1A in the first optocoupler to generate an optical signal, thereby realizing the transmission of the dimming instruction.

[0132] Continuing to refer to Figure 5 , optionally, the feedback unit 210 includes a feedback control chip U1 and a first transistor Q1. The feedback control chip U1 includes a feedback pin FB and a gate drive output pin GATE. The first transistor Q1 is connected in series between the primary side winding and the first grounding end. The gate of the first transistor Q1 is electrically connected to the gate drive output pin GATE. The light receiver OP1B in the first optocoupler is connected in series between the feedback pin FB and the first grounding end.

[0133] Among them, the feedback control chip U1 can identify the optical signal generated by the light emitter IC1A in the first optocoupler based on the light receiver OP1B in the first optocoupler, and receive the dimming instruction by changing the voltage of the feedback pin FB. It can be known that after the feedback control chip U1 receives the dimming instruction, the gate drive output pin GATE of the feedback control chip U1 will adaptively output a gate drive signal, and the first transistor Q1 conducts or turns off according to this gate drive signal, thereby realizing the function that the feedback unit 210 receives the dimming instruction and controls the on-off between the primary winding and the first grounding end accordingly. Based on this, optionally, the dimming circuit further includes a first optocoupler, and the feedback unit 210 and the dimming instruction transfer module 102 transfer the dimming instruction through the first optocoupler.

[0134] Continue to refer to Figure 5 , optionally, the DC-DC conversion module further includes a first inductor L1, a first resistor R1, a first capacitor C1, a second capacitor C2, a first varistor V1, a third capacitor C7, a first diode D6 and a second resistor. The first inductor L1 is connected in series between the AC-DC conversion module 101 and the primary winding; among them, the first inductor L1 is electrically connected to the first end of the primary winding. The first resistor R1 is connected in parallel with the first inductor L1. The first end of the first capacitor C1 is electrically connected to the first end of the first resistor R1, and the second end of the first capacitor C1 is electrically connected to the first grounding end. The first end of the second capacitor C2 is electrically connected to the second end of the first resistor R1, and the second end of the second capacitor C2 is electrically connected to the first grounding end. The first varistor V1 is connected in parallel with the second capacitor C2. The first end of the third capacitor C7 is electrically connected to the first end of the second capacitor C2. The cathode of the first diode D6 is electrically connected to the second end of the third capacitor C7, and the anode of the first diode D6 is electrically connected to the second end of the primary winding. The second resistor is connected in parallel with the third capacitor C7.

[0135] Among them, the first inductor L1, the first resistor R1, the first capacitor C1 and the second capacitor C2 are used to filter out the AC components doped in the first DC voltage DC1, reduce the ripple of the first DC voltage DC1, and smooth the voltage waveform of the first DC voltage DC1. It can be known that the third capacitor C7, the first diode D6 and the second resistor can form an RCD clamp absorption circuit, and this RCD clamp absorption circuit can effectively reduce the switching loss of the first transistor Q1, which is beneficial to improving the electromagnetic interference (EMI) characteristics of the LED dimming circuit.

[0136] It can be understood that Figure 5Exemplarily, it is shown that the second resistor can be formed by connecting 6 resistors in series and / or in parallel, which does not limit the present invention. Exemplarily, the second resistor can also be formed by connecting 2, 3, 4 or 8 resistors in series and / or in parallel. Continuing to refer to Figure 5 , it can be known that the second resistor includes resistor R14, resistor R11, resistor R7, resistor R13, resistor R10 and resistor R6. After resistor R14 and resistor R13 are connected in series, they are connected in parallel with resistor R11 and resistor R10 connected in series with each other, and resistor R7 and resistor R6 connected in series.

[0137] Continuing to refer to Figure 5 , optionally, the DC-DC conversion module 103 further includes a third resistor, a fourth capacitor, a second diode, a fifth capacitor C8, a fourth resistor, a fifth resistor R34 and a third diode D13. The first end of the third resistor is electrically connected to the first end of the secondary winding. The first end of the fourth capacitor is electrically connected to the second end of the third resistor, and the second end of the fourth capacitor serves as the first output end of the dimming circuit. The first end of the second diode is electrically connected to the first end of the secondary winding, and the second end of the second diode is electrically connected to the first output end of the dimming circuit. The first end of the fifth capacitor C8 is electrically connected to the first output end of the dimming circuit, and the second end of the fifth capacitor C8 is electrically connected to the second end of the secondary winding and is also electrically connected to the second grounding end. The fourth resistor is connected in parallel with the fifth capacitor C8. The first end of the fifth resistor R34 is electrically connected to the second end of the secondary winding, and the second end of the fifth resistor R34 is electrically connected to the second output end of the dimming circuit. The anode of the third diode D13 is electrically connected to the second output end of the dimming circuit, and the cathode of the third diode D13 is electrically connected to the second end of the secondary winding.

[0138] Among them, the third resistor, the fourth capacitor and the second diode can form an absorption circuit for the secondary winding. This absorption circuit can absorb the self-induced electromotive force generated by the primary winding of the first transformer T1 during the operation of the LED dimming circuit. At the same time, when the first transistor Q1 is turned off instantaneously, it can also effectively avoid the risk of damaging the first transistor Q1 due to the excessive reverse peak high voltage appearing in the primary winding of the first transformer T1. It can be understood that the third resistor and the fourth capacitor can also suppress the reverse peak voltage, that is, the influence of the surge voltage on the second diode, so as to protect the second diode from damage under the condition that the withstand voltage of the second diode is insufficient.

[0139] It can be understood that Figure 5Exemplarily, it is shown that both the third resistor and the fourth resistor can be formed by connecting three resistors in parallel, the fourth capacitor can be formed by connecting two capacitors in parallel, and the second diode can be formed by connecting two diodes in parallel, which does not limit the present invention. Exemplarily, the third resistor and the fourth resistor may also include only one resistor, or may be formed by connecting two, three, or four resistors in parallel; the fourth capacitor may include only one capacitor, or may be formed by connecting two or more capacitors in parallel; the second diode may include only one diode, or may be formed by connecting two or more diodes in parallel. Continuing to refer to Figure 5 , it can be known that the third resistor includes resistor R44, resistor R45, and resistor R46, the fourth resistor includes resistor R23, resistor R27, and resistor R36, the fourth capacitor includes capacitor C4 and capacitor C19, and the second diode includes diode D10 and diode D11.

[0140] Continuing to refer to Figure 5, optionally, the feedback unit further includes a capacitor C3, a switching transistor Q2, a Schottky diode Z1, a resistor R2, a capacitor C6, a resistor R3, a diode D5, a resistor R4, a resistor R5, an auxiliary coil i, a capacitor C10, a resistor R21, a resistor R22, a capacitor C21, a capacitor C11, a capacitor C13, a diode D1, a resistor R9, a resistor R8, a resistor R12, a resistor R24, a resistor R18, a resistor R19, a resistor R20, and a capacitor C20.It is known that the first end of capacitor C3 is connected to voltage VCC, and the second end of capacitor C3 is electrically connected to the first grounding end; the first end of switching transistor Q2 is electrically connected to the first end of capacitor C3, the second end of switching transistor Q2 is electrically connected to the first end of Schottky diode Z1, and the third end of switching transistor Q2 is electrically connected to the second end of resistor R2; the second end of Schottky diode Z1 is electrically connected to the second end of capacitor C3; the first end of resistor R2 is electrically connected to the first end of Schottky diode Z1; the first end of capacitor C6 is electrically connected to the second end of resistor R2, and the second end of capacitor C6 is electrically connected to the first grounding end; the first end of resistor R3 is electrically connected to the second end of resistor R2, and the second end of resistor R3 is electrically connected to the first end of diode D5; the second end of diode D5 is electrically connected to the first end of resistor R4; the second end of resistor R4 is electrically connected to the first end of resistor R5; the second end of resistor R5 is electrically connected to the second end of auxiliary coil i; the first end of auxiliary coil i is electrically connected to the first end of resistor R4, and the second end of auxiliary coil i is electrically connected to the first grounding end; capacitor C10 is connected in parallel across resistor R5, and the first end of capacitor C10 is electrically connected to the ZCD terminal of feedback control chip U1; the GND terminal of feedback control chip U1 is electrically connected to the first grounding end; the VCC terminal of feedback control chip U1 is connected to voltage VCC, the first end of capacitor C11 is electrically connected to the VCC terminal of feedback control chip U1, and the second end of capacitor C11 is electrically connected to the first grounding end; the first end of resistor R21 is connected to voltage VMAINS, and the second end of resistor R21 is electrically connected to the first end of resistor R22; the second end of resistor R22 is electrically connected to the first end of capacitor C21; the second end of capacitor C21 is electrically connected to the first grounding end; the HV terminal of feedback control chip U1 is connected between resistor R22 and capacitor C21; capacitor C13 is connected in parallel across the light-receiving device OP1B in the first optocoupler; the first end of diode D1 is electrically connected to the gate drive output pin GATE of feedback control chip U1, and the second end of diode D1 is electrically connected to the first end of resistor R9; the second end of resistor R9 is electrically connected to the first end of the first transistor Q1, that is, the gate of the first transistor Q1; the first end of resistor R8 is electrically connected to the first end of diode D1, and the second end of resistor R8 is electrically connected to the second end of resistor R9; the first end of resistor R12 is electrically connected to the second end of resistor R8, and the second end of resistor R12 is electrically connected to the first end of resistor R18; the second end of resistor R18 is electrically connected to the first grounding end; resistor R19 is connected in parallel across resistor R18; resistor R20 is connected in parallel across resistor R19 and is connected in series between the first transistor Q1 and the first grounding end; the first end of resistor R24 is electrically connected to the CS terminal of feedback control chip U1, and the second end of resistor R24 is connected between resistor R12 and resistor R18; the first end of capacitor C20 is electrically connected to the first end of resistor R24, and the second end of capacitor C20 is electrically connected to the first grounding end.

[0141] Continue to refer toFigure 6 , optionally, the dimming instruction transmission module 102 further includes a resistor R26, a capacitor C14, a resistor R28, a capacitor C16, a diode D2, a resistor R15, a resistor R16, a capacitor C5, a resistor R58, a resistor R52, a resistor R55, a resistor R60, a resistor R59, a resistor R62, a capacitor C36, a diode D7, and a resistor R38. It can be known that the first end of the resistor R26 is connected to the dimming instruction, and the second end of the resistor R26 is electrically connected to the first end of the capacitor C14; the second end of the capacitor C14 is electrically connected to the second ground terminal; the first end of the resistor R28 is electrically connected to the first end of the capacitor C14, and the second end of the resistor R28 is electrically connected to the first end of the capacitor C16; the second end of the capacitor C16 is electrically connected to the second ground terminal; the first end of the diode D2 is electrically connected to the first end of the capacitor C16, and the second end of the diode D2 is connected between the resistor R15 and the resistor R16; the first end of the resistor R15 is connected to the +5V voltage, and the second end of the resistor R15 is electrically connected to the first end of the resistor R16; the second end of the resistor R16 is electrically connected to the second ground terminal; the capacitor C5 is connected in parallel across the two ends of the resistor R16; the first end of the resistor R58 is electrically connected to the first input terminal of the first comparator U2B, and the second end of the resistor R58 is connected between the resistor R15 and the resistor R16; the first end of the resistor R52 is connected to the comparison voltage signal, and the second end of the resistor R52 is electrically connected to the first end of the resistor R55; the second end of the resistor R55 is electrically connected to the first end of the resistor R60, and the second end of the resistor R60 is electrically connected to the second ground terminal; the resistor R59 is connected in parallel across the two ends of the resistor R60; the second input terminal of the first comparator U2B is connected between the resistor R55 and the resistor R60; after the capacitor C36 and the resistor R62 are connected in series, they are connected in parallel between the second input terminal and the output terminal of the first comparator U2B; the resistor R38, the light emitter IC1A in the first optocoupler, and the diode D7 are connected in series between the output terminal of the first comparator U2B and the first power supply terminal.

[0142] Based on the above embodiments, the working processes of the DC-DC conversion module 103 and the dimming instruction transmission module 102 provided in this embodiment are as follows:

[0143] When there is a dimming requirement in the LED dimming circuit, the dimming instruction is transmitted to the first input terminal of the first comparator U2B through the resistor R26, the resistor R28, the diode D2, and the resistor R58. At the same time, the comparison voltage signal is transmitted to the second input terminal of the first comparator U2B through the resistor R52 and the resistor R55. The first comparator U2B generates a level signal according to the dimming instruction and the comparison voltage signal, and this level signal causes the light emitter IC1A in the first optocoupler to generate an optical signal. After the light receiver OP1B in the first optocoupler receives this optical signal, the voltage of the feedback pin FB of the feedback control chip U1 is pulled down, and the feedback control chip U1 can identify the dimming requirement of the LED dimming circuit. According to the dimming requirement of the LED dimming circuit, the feedback control chip U1 outputs a gate drive signal through the gate drive output pin GATE, and the first transistor Q1 conducts or turns off according to this gate drive signal, thereby controlling the second DC voltage DC2 output by the DC-DC conversion module 103, realizing the adaptive adjustment of the dimming instruction and the specified brightness of the LED.

[0144] From the working processes of the above DC-DC conversion module 103 and the dimming instruction transmission module 102, it can be seen that the technical solution of this embodiment realizes the conversion from the first DC voltage DC1 to the second DC voltage DC2 by setting the dimming instruction transmission module 102 including the first comparator U2B and the DC-DC conversion module 103 including the first transformer T1 and the feedback unit 210. In addition, in this embodiment, by controlling the second DC voltage DC2, the adaptive adjustment of the dimming instruction and the specified brightness of the LED is realized. The technical solution of this embodiment shows the specific circuit structures of the DC-DC conversion module 103 and the dimming instruction transmission module 102, and the circuit structure is simple, operates stably, and is easy to implement.

[0145] Based on the above embodiments, Figure 7 is the circuit diagram of a current detection module provided by an embodiment of the present invention. As Figure 7 shown, optionally, the dimming circuit further includes a current detection module 104. The current detection module 104 is electrically connected to the second output terminal of the dimming circuit, and the current detection module 104 is used to detect the current of the second output terminal. Based on this, in this embodiment, by setting the current detection module 104 to detect the current of the second output terminal of the dimming circuit, the problem of electric shock accidents easily caused by single-end power-on and the other end conducting electricity during the installation process of the existing LED lighting device is overcome, and the electric shock risk of the installation personnel is effectively avoided. It can be understood that the embodiments of the present invention include but are not limited to detecting the current of the second output terminal. Exemplarily, the current detection module 104 can also be used to detect the current of the first output terminal.

[0146] Specifically, optionally, the current detection module 104 includes a fifth comparator U2A, an eighth resistor R47, a ninth resistor R49, a tenth resistor R51, an eleventh resistor R48, a twelfth resistor R50, a thirteenth resistor R25, a seventh capacitor C28, a fourteenth resistor R35, and an eighth capacitor C29. The fifth comparator U2A includes a first input terminal, a second input terminal, and an output terminal. The first end of the eighth resistor R47 is electrically connected to the second output terminal of the dimming circuit. The first end of the ninth resistor R49 is electrically connected to the second end of the eighth resistor R47, and the second end of the ninth resistor R49 is electrically connected to the first input terminal of the fifth comparator U2A. The first end of the tenth resistor R51 is electrically connected to the second ground terminal, and the second end of the tenth resistor R51 is electrically connected to the first input terminal of the fifth comparator U2A. The first end of the eleventh resistor R48 is electrically connected to the second ground terminal. The first end of the twelfth resistor R50 is electrically connected to the second end of the eleventh resistor R48; the second end of the twelfth resistor R50 is electrically connected to the second input terminal of the fifth comparator U2A. The first end of the thirteenth resistor R25 is electrically connected to the second end of the twelfth resistor R50; the second end of the thirteenth resistor R25 is electrically connected to the output terminal of the fifth comparator U2A. The first end of the seventh capacitor C28 is electrically connected to the first end of the tenth resistor R51, and the second end of the seventh capacitor C28 is electrically connected to the first end of the twelfth resistor R50. The first end of the fourteenth resistor R35 is electrically connected to the output terminal of the fifth comparator U2A, and the second end of the fourteenth resistor R35 serves as the output terminal of the current detection module 104. The first end of the eighth capacitor C29 is electrically connected to the second end of the fourteenth resistor R35, and the second end of the eighth capacitor C29 is electrically connected to the second ground terminal.

[0147] Continuing to refer to Figure 7 , optionally, the current detection module 104 further includes a resistor R29, and the first end of the eighth resistor R47 is electrically connected to the second output terminal of the dimming circuit through the resistor R29. It can be known that when a current exists at the second output terminal of the dimming circuit, the fifth comparator U2A outputs a high level; when no current exists at the second output terminal of the dimming circuit, the fifth comparator U2A outputs a low level. It can be understood that the embodiment of the present invention can, but is not limited to, amplify the output signal of the current detection module 104 through a post-stage amplifier circuit and perform a warning in the form of an alarm device such as a buzzer or a warning light, so as to further ensure the life safety of the installation personnel.

[0148] Based on the above embodiments, Figure 8 is a circuit diagram of an AC-DC conversion module provided by an embodiment of the present invention. As Figure 8As shown, optionally, the AC-DC conversion module 101 includes an electromagnetic compatibility unit 220 and a rectifier bridge B1. The electromagnetic compatibility unit 220 is used to resist electromagnetic interference and transmit the filtered first AC voltage AC1 to the subsequent circuit. The rectifier bridge B1 is used to convert the filtered first AC voltage AC1 into a first DC voltage DC1.

[0149] Among them, the electromagnetic compatibility unit 220 can be any circuit that can implement the electromagnetic compatibility function, and the rectifier bridge B1 can be any rectifier circuit. The embodiments of the present invention do not limit this. Exemplarily, the rectifier bridge B1 can be an uncontrolled rectifier circuit, or a semi-controlled rectifier circuit, or a fully controlled rectifier circuit.

[0150] Continue to refer to Figure 8 , optionally, the electromagnetic compatibility unit 220 includes a fuse FR1, a varistor V2, a transformer LF2, a capacitor CX1, a transformer LF1, a diode D3, and a diode D4. It can be known that the first end of the fuse FR1 is electrically connected to the input terminal P3 of the electromagnetic compatibility unit 220, and the second end of the fuse FR1 is electrically connected to the third end of the transformer LF2; the second end of the varistor V2 is electrically connected to the input terminal P4 of the electromagnetic compatibility unit 220, and the varistor V2 is connected in parallel between the third end and the first end of the transformer LF2; the capacitor CX1 is connected in parallel between the fourth end and the second end of the transformer LF2, and is also connected in parallel between the third end and the first end of the transformer LF1; the fourth end and the second end of the transformer LF2 are the same-named terminals; the fourth end of the transformer LF1 is electrically connected to the first end of the diode D3, and the second end of the transformer LF1 is electrically connected to the second end of the diode D4; the fourth end and the second end of the transformer LF1 are the same-named terminals; the second end of the diode D3 is electrically connected to the first end of the diode D4 and is connected to the voltage VMAINS.

[0151] Continue to refer to Figure 8 , optionally, the first end of the diode D3 is electrically connected to the third end of the rectifier bridge B1, the second end of the diode D4 is electrically connected to the first end of the rectifier bridge B1, and the fourth end of the rectifier bridge B1 is electrically connected to the first grounding end. In addition, the second end of the rectifier bridge B1 serves as the output terminal of the AC-DC conversion module 101 for outputting the first DC voltage DC1.

[0152] In summary, the technical solution of this embodiment weakens the electromagnetic interference received by the dimming circuit by setting the electromagnetic compatibility unit 220, improves the electromagnetic interference resistance ability of the dimming circuit, and also converts the first AC voltage AC1 into the first DC voltage DC1 by setting the rectifier bridge B1. The circuit structure provided by this embodiment is simple, the hardware cost is low, and it is easy to implement.

[0153] Based on the above embodiments, Figure 9 is a circuit diagram of another DC-DC conversion module provided by an embodiment of the present invention. As Figure 9 shown, optionally, the DC-DC conversion module 103 includes a second transformer T2', a first switch unit Q2', a second switch unit Q4', a first control unit 310, a third switch unit Q5', a fourth switch unit Q1' and a second control unit 320. The second transformer T2' includes a primary winding and two secondary windings connected in series. The connection point of the two secondary windings is defined as the output node, and the two ends of the two secondary windings different from the output node are respectively the first end and the second end. The first switch unit Q2' is connected in series between the output end of the AC-DC conversion module 101 and the primary winding. The second switch unit Q4' is connected in parallel with the primary winding. The first control unit 310 is configured to receive a dimming instruction and control the on / off of the first switch unit Q2' and the second switch unit Q4' accordingly. The third switch unit Q5' is connected in series between the first end of the secondary winding and the first voltage terminal. The fourth switch unit Q1' is connected in series between the second end of the secondary winding and the second voltage terminal. The second control unit 320 is configured to control the on / off of the third switch unit Q5' and the fourth switch unit Q1'. Wherein, the output node is electrically connected to the first output end of the dimming circuit, and the second voltage terminal is electrically connected to the second output end of the dimming circuit.

[0154] Among them, the first switch unit Q2' can form a closed loop with the output end of the AC-DC conversion module 101, the primary winding of the second transformer T2' and the first ground terminal, and the second switch unit Q4' can form a closed loop with the primary winding of the second transformer T2' and the first ground terminal.

[0155] It can be known that when the first switching unit Q2' is turned on and the second switching unit Q4' is turned off, the first DC voltage DC1 output by the AC-DC conversion module 101 is connected to the first grounding end through the first switching unit Q2' and the primary side winding of the second transformer T2'; when the first switching unit Q2' is turned off and the second switching unit Q4' is turned on, the current flowing through the primary side winding of the second transformer T2' is difficult to change suddenly, and the voltage across the primary side winding is maintained until the first control unit 310 controls the first switching unit Q2' to be turned on again and turns off the second switching unit Q4'. It can be understood that the first switching unit Q2' and the second switching unit Q4' cannot be turned on or off simultaneously. When the first switching unit Q2' and the second switching unit Q4' are turned on simultaneously, the first DC voltage DC1 output by the AC-DC conversion module 101 is directly connected to the first grounding end through the first switching unit Q2' and the second switching unit Q4'. At this time, the primary side winding of the second transformer T2' is short-circuited by the second switching unit Q4'; when the first switching unit Q2' and the second switching unit Q4' are turned off simultaneously, the LED dimming circuit is in an open circuit state and cannot perform dimming work.

[0156] Continue to refer to Figure 9 , it can be known that the same-name ends of the two secondary side windings are both located on the side close to the output node. Based on this, when the third switching unit Q5' and / or the fourth switching unit Q1' is turned on, the currents induced in the two secondary side windings are both transmitted to the first output end of the dimming circuit through the output node.

[0157] Based on the above embodiments, Figure 10 is a circuit diagram of another dimming instruction transmission module provided by an embodiment of the present invention. As Figure 10 shown, optionally, the dimming instruction transmission module 102 includes a third comparator U3A' and a fourth comparator U3B'. The first input terminal of the third comparator U3A' is connected to the dimming instruction, and the second input terminal of the third comparator U3A' is connected to the comparison voltage signal. The first terminal of the fourth comparator U3B' is electrically connected to the second grounding end, and the second terminal of the fourth comparator U3B' is connected to the comparison voltage signal. The light emitter OP1A' in the second optocoupler is connected in series between the output terminal of the third comparator U3A' and the first power supply terminal; the output terminal of the fourth comparator U3B' is electrically connected to the output terminal of the third comparator U3A'.

[0158] Among them, the third comparator U3A' and the fourth comparator U3B' are used to form a window comparator. It is known that this window comparator has two reference comparison terminals, namely the second input terminal of the third comparator U3A' and the second terminal of the fourth comparator U3B'. Exemplarily, assuming that the set values of the two reference comparison terminals are +5V and +10V respectively, when the level value of the dimming instruction CV_ADJ is within the range of [+5V, +10V], the window comparator will maintain the initial high-level output state, and the light emitter OP1A' in the second optocoupler will not emit light; correspondingly, when the level value of the dimming instruction CV_ADJ is lower than +5V or higher than +10V, the output terminal of the third comparator U3A' or the fourth comparator U3B' will flip to the low-level state, and the light emitter OP1A' in the second optocoupler will emit light to transmit the dimming instruction. It can be seen that the dimming instruction transmission module 102 provided in this embodiment is no longer limited to setting the dimming when the dimming instruction is higher or lower than a certain comparison voltage signal. It can be understood that such a setting can effectively broaden the adjustment range of the LED dimming circuit, improve the flexibility and practicality of the LED dimming circuit. In addition, the parallel output of the comparator can also save the I / O ports of the subsequent circuit, which is beneficial to the miniaturization of the LED dimming circuit.

[0159] Continue to refer to Figure 9 Optionally, the first control unit includes a resonant control chip U2'. The resonant control chip U2' includes a resonant control pin RFMIN, a first gate drive output pin HVG, and a second gate drive output pin LVG. The light receiver OP2B' in the second optocoupler is connected in series between the resonant control pin RFMIN and the first ground terminal. The first gate drive output pin HVG is electrically connected to the first switching unit Q2', and the second gate drive output pin LVG is electrically connected to the second switching unit Q4'.

[0160] Among them, the resonant control chip U2' can recognize the optical signal generated by the light emitter OP1A' in the second optocoupler based on the light receiver OP2B' in the second optocoupler, and receive the dimming instruction through the voltage change of the resonant control pin RFMIN. It is known that after the resonant control chip U2' receives the dimming instruction, the first gate drive output pin HNG and the second gate drive output pin LVG of the resonant control chip U2' will adaptively output the first gate drive signal and the second gate drive signal. The first switching unit Q2' conducts or turns off according to the first gate drive signal, and the second switching unit Q4' conducts or turns off according to the second gate drive signal, thereby realizing the function that the first control unit 310 receives the dimming instruction and adjusts the output voltage of the LED dimming circuit accordingly. Based on this, optionally, the dimming circuit further includes a second optocoupler, and the first control unit 310 and the dimming instruction transmission module 102 transmit the dimming instruction through the second optocoupler.

[0161] Continue to refer to Figure 9 , optionally, the second control unit 320 includes an LLC synchronous rectifier IC2'. The LLC synchronous rectifier IC2' includes a first voltage pin VDD, a second voltage pin VSS, a third voltage pin VD1, a fourth voltage pin VD2, a third gate drive pin VG1, and a fourth gate drive pin VG2. The first voltage pin VDD is connected to the second voltage signal, the second voltage pin VSS is electrically connected to the first voltage terminal and is also electrically connected to the second voltage terminal. The third voltage pin VD1 is electrically connected to the first end of the secondary winding, and the fourth voltage pin VD2 is electrically connected to the second end of the secondary winding. The third gate drive pin VG1 is electrically connected to the third switch unit Q5', and the fourth gate drive pin VG2 is electrically connected to the fourth switch unit Q1'.

[0162] Wherein, the LLC synchronous rectifier IC2' can adaptively generate a third gate drive signal and a fourth gate drive signal according to the second voltage signal, the voltage signal of the first voltage terminal, the voltage signal of the second voltage terminal, the voltage signal of the first end of the secondary winding, and the voltage signal of the second end of the secondary winding, so as to control the on and off of the third switch unit Q5' and the fourth switch unit Q1'.

[0163] Continue to refer to Figure 9 , optionally, the DC-DC conversion module 103 further includes a second inductor L1A, and the second inductor L1A is serially connected between the first switch unit Q2' and the primary winding. It can be known that the second inductor L1A is used to make the current flowing through the primary winding of the second transformer T2' more difficult to mutate when the first switch unit Q2' is turned off and the second switch unit Q4' is turned on, which is beneficial to maintaining the voltage across the primary winding until the first control unit 310 controls the first switch unit Q2' to be turned on again and turns off the second switch unit Q4'.

[0164] Continue to refer to Figure 9 , optionally, the DC-DC conversion module 103 further includes a sixth resistor R24', a seventh resistor, and a sixth capacitor C4'. The sixth resistor R24' is serially connected between the third switch unit Q5' and the second output terminal of the dimming circuit. The first end of the seventh resistor is electrically connected to the first output terminal of the dimming circuit, and the second end of the seventh resistor is electrically connected to the third switch unit Q5'. The sixth capacitor C4' is connected in parallel with the seventh resistor.

[0165] Wherein, Figure 9 it is exemplarily shown that the seventh resistor can be formed by paralleling 3 resistors, which does not limit the present invention. Exemplarily, the seventh resistor can also only include 1 resistor, or can be formed by paralleling 2, 4 or 5 resistors. Continue to refer to Figure 7, it can be known that the seventh resistor includes resistor R12’, resistor R8’ and resistor R9’.

[0166] Continue to refer to Figure 9 , optionally, the DC-DC conversion module 103 further includes diode D3’, resistor R11’, resistor R17’, resistor R21’, diode D5’, resistor R25’, resistor R28’, resistor R31’, capacitor C19’, diode D7’, capacitor C24’ and capacitor C25’. It can be known that the first end of diode D3’ is connected to the first gate drive signal, and the second end of diode D3’ is electrically connected to the first end of resistor R11’; the second end of resistor R11’ is electrically connected to the gate of the first switch unit Q2’; resistor R17’ is connected in parallel between the first end of diode D3’ and the second end of resistor R11’; the first end of resistor R21’ is electrically connected to the second end of resistor R17’, the second end of resistor R21’ is connected to voltage HB, and the second end of resistor R21’ is connected between the second switch unit Q4’ and the second inductor L1A; the first end of diode D5’ is connected to the second gate drive signal, and the second end of diode D5’ is electrically connected to the first end of resistor R25’; the second end of resistor R25’ is electrically connected to the gate of the second switch unit Q4’; resistor R28’ is connected in parallel between the first end of diode D5’ and the second end of resistor R25’; the first end of resistor R31’ is electrically connected to the second end of resistor R28’, and the second end of resistor R31’ is connected between the second switch unit Q4’ and the first ground terminal; capacitor C19’ is connected in series between the primary side winding of the second transformer T2’ and the second switch unit Q4’, and the first end of capacitor C19’ is electrically connected to the first ground terminal; diode D7’ is connected in parallel across both ends of capacitor C19’; the first end of capacitor C24’ is connected to voltage CS, the second end of capacitor C24’ is electrically connected to the first end of capacitor C25’; the second end of capacitor C25’ is electrically connected to the second end of diode D7’.

[0167] Continue to refer to Figure 9, optionally, the DC-DC conversion module further includes a resistor R1', a capacitor C1', a resistor R7', a resistor R20', a capacitor C12', a resistor R26', a capacitor C8', a capacitor C9', a capacitor C3', a capacitor C14' and a resistor R10'. It can be known that after the resistor R1' and the capacitor C1' are connected in series with each other, they are connected in parallel across both ends of the fourth switching transistor Q1'; the first end of the resistor R7' is connected to the fourth gate drive signal and is electrically connected to the gate of the fourth switching transistor Q1', and the second end of the resistor R7' is connected between the second end of the capacitor C1' and the second end of the capacitor C12'; the first end of the capacitor C12' is electrically connected to the second end of the resistor R20'; the first end of the resistor R20' is connected between the first end of the secondary winding and the third switching transistor Q5'; the first end of the resistor R26' is connected to the third gate drive signal and is electrically connected to the gate of the third switching transistor Q5', the second end of the resistor R26' is connected to the second end of the capacitor C12' and is electrically connected to the first voltage terminal; the capacitor C8' is connected in parallel between the output node and the first voltage terminal; the capacitor C9' is connected in parallel across both ends of the capacitor C8'; the first end of the capacitor C3' is electrically connected to the first end of the sixth resistor R24', and the second end of the capacitor C3' is electrically connected to the first end of the capacitor C14'; the second end of the capacitor C14' is electrically connected to the second end of the sixth resistor R24'; the resistor R10' is connected in parallel across both ends of the sixth capacitor C4'.

[0168] Continue to refer to Figure 9, optionally, the first control unit 310 further includes a resistor R35', a resistor R36', a resistor R39', a resistor R42', a capacitor C29', a capacitor C33', a capacitor C34', a resistor R46', a capacitor C23', a capacitor C26', a capacitor C27', a resistor R40', a capacitor C28', a capacitor C35', a capacitor C40', a triode Q7', a resistor R51', a capacitor C42', a resistor R55', a resistor R64', a resistor R60', a capacitor C44', a resistor R62', a capacitor C45', a capacitor C43', a resistor R65', a diode D10', a diode D12' and a resistor R56'. It is known that the first end of the resistor R35' is connected to the voltage VBUS+, and the second end of the resistor R35' is electrically connected to the first end of the resistor R36'; the second end of the resistor R36' is electrically connected to the first end of the resistor R39'; the second end of the resistor R39' is electrically connected to the LINE terminal of the resonant control chip U2'; the resistor R42' is connected in parallel across both ends of the capacitor C29'; the first end of the capacitor C29' is connected to the first ground terminal, and the second end of the capacitor C29' is connected to the second end of the resistor R39'; the first end of the capacitor C33' is connected to the first end of the capacitor C29', and the second end of the capacitor C33' is connected to the DELAY terminal of the resonant control chip U2'; the resistor R46' is connected in parallel across both ends of the capacitor C33'; the first end of the capacitor C34' is connected to the first end of the capacitor C33', and the second end of the capacitor C34' is connected to the CF terminal of the resonant control chip U2'; the first end of the capacitor C23' is connected to the voltage VCC, and the second end of the capacitor C23' is connected to the first ground terminal; the capacitor C26' is connected in parallel across both ends of the capacitor C23'; the capacitor C27' is connected in parallel across both ends of the capacitor C26'; the first end of the resistor R40' is connected to the first end of the capacitor C27', the second end of the resistor R40' is connected to the first end of the capacitor C28', and is also connected to the VCC terminal of the resonant control chip U2'; the second end of the capacitor C28' is connected to the first ground terminal; the capacitor C35' is connected between the VBOOT terminal and the OUT terminal of the resonant control chip U2'; the OUT terminal of the resonant control chip U2' is connected to the voltage HB; the capacitor C40' is connected in parallel across the collector and emitter of the triode Q7'; the collector of the triode Q7' is electrically connected to the second end of the capacitor C42', the emitter of the triode Q7' is electrically connected to the first end of the resistor R51', and the base of the triode Q7' is electrically connected to the first end of the capacitor C42'; the second end of the resistor R51' is connected between the resistor R55' and the resistor R64'; after the resistor R55' and the resistor R64' are connected in series, they are connected in parallel with the capacitor C42'; the first end of the resistor R55' is connected to the CSS terminal of the resonant control chip U2', and the second end of the resistor R55' is connected to the resonant control pin RFMIN of the resonant control chip U2'; the DIS terminal of the resonant control chip U2' is connected to the first ground terminal;The first end of resistor R60’ is electrically connected to the resonance control pin RFMIN of resonance control chip U2’, and the second end of resistor R60’ is electrically connected to the first end of light receiver OP2B’ in the second optocoupler; the second end of light receiver OP2B’ in the second optocoupler is electrically connected to the first ground terminal; capacitor C44’ is connected in parallel across both ends of light receiver OP2B’ in the second optocoupler; the first end of resistor R62’ is electrically connected to the first end of capacitor C44’, the second end of resistor R62’ is electrically connected to the first end of capacitor C45’, and is also electrically connected to the STBY terminal of resonance control chip U2’; the second end of capacitor C45’ is electrically connected to the first ground terminal; the GND terminal of resonance control chip U2’ is electrically connected to the first ground terminal; the first end of capacitor C43’ is electrically connected to the ISEN terminal of resonance control chip U2’, and the second end of capacitor C43’ is electrically connected to the first ground terminal; resistor R65’ is connected in parallel with capacitor C43’; after diode D10’ and diode D12’ are connected in series, they are connected in parallel across both ends of resistor R65’; the first end of resistor R56’ is connected between diode D10’ and diode D12’, and the second end of resistor R56’ is connected to voltage CS’.;

[0169] Continue to refer to Figure 9 , Optionally, the second control unit 320 further includes diode D8’, resistor R37’, resistor R43’, capacitor C32’, resistor R45’, diode D9’, resistor R38’, resistor R44’, capacitor C30’ and capacitor C31’. It can be known that the first end of diode D8’ outputs the fourth gate drive signal, and the second end of diode D8’ is electrically connected to the fourth gate drive pin VG2 of LLC synchronous rectifier IC2’; resistor R37’ is connected in parallel with diode D8’; the first end of resistor R43’ is electrically connected to the LL terminal of LLC synchronous rectifier IC2’, and the second end of resistor R43’ is electrically connected to the second output terminal of the dimming circuit; capacitor C32’ is connected in parallel with resistor R43’; the first end of resistor R45’ is electrically connected to the fourth voltage pin VD2 of LLC synchronous rectifier IC2’, and the second end of resistor R45’ is electrically connected to the second voltage terminal; the second end of diode D9’ outputs the third gate drive signal, and the first end of diode D9’ is electrically connected to the third gate drive pin VG1 of LLC synchronous rectifier IC2’; resistor R38’ is connected in parallel with diode D9’; the first end of resistor R44’ is electrically connected to the third voltage pin VD1 of LLC synchronous rectifier IC2’, and the second end of resistor R44’ is electrically connected to the first voltage terminal CS1; the first end of capacitor C30’ is connected to the second voltage signal and is electrically connected to the first voltage pin VDD of LLC synchronous rectifier IC2’, and the second end of capacitor C30’ is electrically connected to the second output terminal of the dimming circuit; capacitor C31’ is connected in parallel with capacitor C30’.

[0170] Continue to refer to Figure 10, optionally, the dimming instruction transmission module 102 further includes a resistor R52', a resistor R57', a diode D11', a diode D13', a resistor R63', a resistor R74', a capacitor C39', a resistor R59', a capacitor C46', a resistor R66', a resistor R67', a resistor R58', a resistor R54', a capacitor C41', a resistor R69', a resistor R73', a resistor R71', a capacitor C48', a resistor R75', a capacitor C51', a resistor R78', a resistor R79', a capacitor R49' and a resistor R80'.It is known that the first end of the resistor R52' is connected to a 15V voltage, and the second end of the resistor R52' is electrically connected to the first end of the light emitter OP1A' in the second optocoupler; the resistor R57' is connected in parallel with the light emitter OP1A' in the second optocoupler; the first end of the diode D11' is electrically connected to the second end of the light emitter OP1A' in the second optocoupler, and the second end of the diode D11' is electrically connected to the first end of the resistor R63'; the second end of the resistor R63' is electrically connected to the output end of the third comparator U3A'; after the capacitor C39' and the resistor R59' are connected in series, they are connected in parallel between the output end and the second input end of the third comparator U3A'; the second end of the resistor R58' is electrically connected to the second input end of the third comparator U3A', and the first end of the resistor R58' is connected to the voltage VO+; the mutually series-connected resistor R54' and capacitor C41' are connected in parallel with the resistor R58'; the first end of the resistor R69' is electrically connected to the second end of the resistor R58', and the second end of the resistor R69' is electrically connected to the first end of the resistor R73'; the second end of the resistor R73' is electrically connected to the second output end of the dimming circuit; the first end of the capacitor C46' is electrically connected to the first input end of the third comparator U3A', and the second end of the capacitor C46' is electrically connected to the second output end of the dimming circuit; the first end of the resistor R66' is electrically connected to the first end of the capacitor C46', and the second end of the resistor R66' is electrically connected to the first end of the resistor R67'; the second end of the resistor R67' is connected to the voltage Vref; the dimming command CV_ADJ is input to the first input end of the third comparator U3A' between the resistor R66' and the resistor R67'; the first end of the diode D13' is electrically connected to the first end of the diode D11', and the second end of the diode D13' is electrically connected to the first end of the resistor R74'; the second end of the resistor R74' is electrically connected to the output end of the fourth comparator U3B'; the mutually series-connected capacitor C48' and resistor R75' are connected in parallel between the output end and the second end of the fourth comparator U3B'; the first end of the resistor R71' is electrically connected to the second end of the capacitor C46', and the second end of the resistor R71' is electrically connected to the second end of the resistor R75'; the capacitor C51' is connected in parallel between the third end and the fourth end of the fourth comparator U3B', the third end of the fourth comparator U3B' is electrically connected to the second output end of the dimming circuit, and the fourth end of the fourth comparator U3B' is connected to a 15V voltage; the first end of the resistor R78' is connected to the voltage Verf, and the second end of the resistor R78' is electrically connected to the first end of the fourth comparator U3B'; the first end of the resistor R79' is electrically connected to the second end of the resistor R78', and the second end of the resistor R79' is electrically connected to the second ground terminal; the capacitor C49' is connected in parallel with the resistor R78'; the resistor R80' is connected in parallel with the resistor R79'.

[0171] The technical solution of this embodiment realizes the conversion from the first DC voltage DC1 to the second DC voltage DC2 by providing a dimming instruction transfer module 102 including a third comparator U3A' and a fourth comparator U3B', and a DC-DC conversion module 103 including a second transformer T2', a first switch unit Q2', a second switch unit Q4', a first control unit 310, a third switch unit Q5', a fourth switch unit Q1' and a second control unit 320. In addition, by controlling the second DC voltage DC2, this embodiment realizes the adaptive adjustment of the dimming instruction and the specified brightness of the LED. The technical solution of this embodiment shows the specific circuit structures of the DC-DC conversion module 103 and the dimming instruction transfer module 102, which have a simple circuit structure, stable operation and are easy to implement.

[0172] Based on the above embodiments, Figure 11 is a circuit diagram of another current detection module provided by an embodiment of the present invention. As Figure 11 shown, optionally, the dimming circuit further includes a current detection module 340. The current detection module 340 is electrically connected to the second output end of the dimming circuit, and the current detection module 340 is used to detect the current at the second output end. Specifically, the current detection module 340 includes a sixth comparator U5', a fifteenth resistor R81', a ninth capacitor C55', a sixteenth resistor R85', a seventeenth resistor R84' and a tenth capacitor C54'. The sixth comparator U5' includes a first input end, a second input end and an output end. The first end of the fifteenth resistor R81' is electrically connected to the second output end of the dimming circuit, and the second end of the fifteenth resistor R81' is electrically connected to the first input end of the sixth comparator U5'. The first end of the ninth capacitor C55' is electrically connected to the first input end of the sixth comparator U5', and the second end of the ninth capacitor C55' is electrically connected to the second input end of the sixth comparator U5'. The first end of the sixteenth resistor R85' is connected to a comparison voltage signal, and the second end of the sixteenth resistor R85' is electrically connected to the second input end of the sixth comparator U5'. The first end of the seventeenth resistor R84' is electrically connected to the output end of the sixth comparator U5', and the second end of the seventeenth resistor R84' serves as the output end of the current detection module 340. The first end of the tenth capacitor C54' is electrically connected to the output end of the current detection module 340, and the second end of the tenth capacitor C54' is electrically connected to the second output end of the dimming circuit.

[0173] Continue to refer to Figure 11, optionally, the current detection module 340 further includes a resistor R83', a resistor R88', a capacitor C53', a resistor R82' and a capacitor C52'. It can be known that the first end of the resistor R83' is electrically connected to the second grounding end, and the second end of the resistor R83' is electrically connected to the second end of the sixteenth resistor R85'; the resistor R88' is in parallel with the ninth capacitor C55'; the capacitor C53' is connected in parallel between the first input terminal and the second input terminal of the sixth comparator U5', and the first end of the capacitor C53' is electrically connected to the second end of the fifteenth resistor R81'; the first end of the resistor R82' is connected between the fifteenth resistor R81' and the capacitor C53', and the second end of the resistor R82' is connected between the output terminal of the sixth comparator U5' and the seventeenth resistor R84'; the first end of the capacitor C52' is connected to a 5V voltage, and the second end of the capacitor C52' is electrically connected to the second output terminal of the dimming circuit.

[0174] It can be known that when a current is detected at the second output terminal of the dimming circuit, the sixth comparator U5' outputs a high level; when no current is detected at the second output terminal of the dimming circuit, the sixth comparator U5' outputs a low level. It can be understood that the embodiment of the present invention can, but is not limited to, amplify the output signal of the current detection module 340 through a post-stage amplifier circuit and give an alarm based on an alarm device such as a buzzer or a warning light to further ensure the safety of installation personnel.

[0175] In summary, in this embodiment, by setting the current detection module 340 to detect the current at the second output terminal of the dimming circuit, the problem of electric shock accidents easily caused by single-end power-on and the other end being conductive during the installation of existing LED lighting devices is overcome, and the electric shock risk of installation personnel is effectively avoided.

[0176] Based on the above embodiments, Figure 12 is a circuit diagram of another AC-DC conversion module provided by an embodiment of the present invention. As Figure 12 shown, optionally, the AC-DC conversion module 101 includes an electromagnetic compatibility unit 350 and a rectifier bridge BD1'. The electromagnetic compatibility unit 350 is used to resist electromagnetic interference and transmit the filtered first AC voltage AC1 to the subsequent circuit. The rectifier bridge BD1' is used to convert the filtered first AC voltage AC1 into a first DC voltage DC1.

[0177] Among them, the electromagnetic compatibility unit 350 can be any circuit that can achieve electromagnetic compatibility functions, and the rectifier bridge BD1' can be any rectifier circuit, and the embodiment of the present invention does not limit this. Exemplarily, the rectifier bridge BD1' can be an uncontrolled rectifier circuit, or a semi-controlled rectifier circuit, or a fully controlled rectifier circuit.

[0178] Continue to refer to Figure 12, optionally, the electromagnetic compatibility unit includes a fuse F1', a varistor MOV1', a capacitor CX1', a capacitor CY4', a capacitor CY3', a transformer LF, a resistor RX2', a resistor RX1', a resistor RX3' and a negative temperature coefficient resistor RTH1'. It can be known that the first end of the fuse F1' is electrically connected to the first end of the varistor MOV1', and the second end of the fuse F1' is electrically connected to the third input terminal of the electromagnetic compatibility unit 350; the second end of the varistor MOV1' is electrically connected to the second input terminal of the electromagnetic compatibility unit 350; the capacitor CX1' is connected in parallel with the varistor MOV1'; the first end of the capacitor CY4' is connected between the second end of the capacitor CX1' and the second end of the varistor MOV1', and the second end of the capacitor CY4' is electrically connected to the first input terminal of the electromagnetic compatibility unit 350; the capacitor CY3' is connected in parallel between the first end of the capacitor CX1' and the second end of the capacitor CY4', and the second end of the capacitor CY3' is electrically connected to the third ground terminal; the first end of the transformer LF is electrically connected to the first end of the capacitor CY3', the second end of the transformer LF is electrically connected to the second end of the capacitor CX1', the third end of the transformer LF is connected to the voltage L1, and the fourth end of the transformer LF is connected to the voltage AC2; the resistors RX2', RX1' and RX3' connected in series are connected in parallel between the third end and the fourth end of the transformer LF; the second end of the negative temperature coefficient resistor RTH1' is electrically connected to the second end of the resistor RX3'.

[0179] Continue to refer to Figure 12 , optionally, the rectifier bridge BD1' includes four diodes connected end to end, and the AC-DC conversion module 101 further includes a capacitor CY1' and a capacitor C10'. It can be known that the first end of the rectifier bridge BD1' is electrically connected to the first end of the resistor RX2', the second end of the rectifier bridge BD1' is used to output the first DC voltage DC1, the third end of the rectifier bridge BDI' is electrically connected to the first end of the negative temperature coefficient resistor RTH1', and the fourth end of the rectifier bridge BD1' is electrically connected to the third ground terminal through the capacitor CY1'; the first end of the capacitor C10' is electrically connected to the second end of the rectifier bridge BD1', the second end of the capacitor C10' is electrically connected to the first end of the capacitor CY1', and the second end of the capacitor C10' is also electrically connected to the first ground terminal.

[0180] It can be understood that since the negative temperature coefficient resistor RTH1' has the characteristic of high resistance value when powered on, during the initial power-on process of the dimming circuit, the negative temperature coefficient resistor RTH1' can weaken the impact of the sudden applied voltage or current on the circuit system and enhance the impact resistance of the dimming circuit. When the dimming circuit works stably, the resistance value of the negative temperature coefficient resistor RTH1' decreases, which can reduce the impact on the power efficiency.

[0181] It can be seen that, in the technical solution of this embodiment, by providing the electromagnetic compatibility unit 350, the electromagnetic interference received by the dimming circuit is reduced, the electromagnetic interference resistance of the dimming circuit is improved, and the first AC voltage AC1 is converted into the first DC voltage DC1 by providing the rectifier bridge BD1'. The circuit provided by this embodiment is simple, low in cost, and easy to implement.

[0182] Based on the above embodiment, Figure 13 is the circuit diagram of a power factor correction module provided by an embodiment of the present invention. As Figure 13 shown, optionally, the dimming circuit further includes a power factor correction module 360, and the power factor correction module 360 is connected between the AC-DC conversion module 101 and the DC-DC conversion module 103. The power factor correction module 360 is configured to perform power factor correction on the first DC voltage DC1 and then transmit it to the DC-DC conversion module 103.

[0183] It can be understood that the power factor correction module 360 can be any power factor correction circuit, and the embodiments of the present invention do not limit this. Exemplarily, the power factor correction module 360 can be an active power factor correction circuit or a passive power factor correction circuit.

[0184] Continue to refer to Figure 13, optionally, the power factor correction module 360 includes a power factor correction chip U1', resistors R3', R14', R19', R4', R15', R', R30', capacitors C15', C17', C16', diode D2', zener diode ZD1', capacitor C2', resistor R2', resistor R13', capacitor C7', transformer T, capacitor C5', resistor R6', capacitor C11', diode D4', resistor R18', resistor R23', resistor R27', resistor R29', capacitor C18', resistor R33', MOS transistor Q3', diode D1', resistor R5', resistor R16', capacitor C13', resistor R22' and capacitor C6'. It can be known that resistors R3', R14', R19' and R30' are connected in series between the second terminal of the rectifier bridge BD1' and the first ground terminal; capacitor C15' is connected in parallel across resistor R30'; resistors R4', R15' and R' connected in series are connected between the first terminal of resistor R3' and the VCC terminal of the power factor correction chip U1'; the first terminal of capacitor C17' is connected between the second terminal of resistor R19' and the VCC terminal of the power factor correction chip U1', and the second terminal of capacitor C17' is electrically connected to the second terminal of capacitor C15'; capacitor C16' is connected in parallel with capacitor C17'; the MUTL terminal of the power factor correction chip U1' is electrically connected to the first terminal of resistor R30'; the first terminal of diode D2' is electrically connected to the first terminal of capacitor C17', and the second terminal of diode D2' is electrically connected to the first ground terminal through the zener diode ZD1'; the first terminal of capacitor C2' is electrically connected to the second terminal of diode D2', and the second terminal of capacitor C2' is electrically connected to the first terminal of resistor R2'; the second terminal of resistor R2' is electrically connected to the first terminal of resistor R13', and the second terminal of resistor R13' is electrically connected to the ZCD terminal of the power factor correction chip U1'; capacitor C7' is connected between the ZCD terminal of the power factor correction chip U1' and the first ground terminal; the first terminal of transformer T is electrically connected to the second terminal of resistor R2', the second terminal of transformer T is electrically connected to the second terminal of the rectifier bridge BD1', and the fourth terminal of transformer T is electrically connected to the first ground terminal; the GND terminal of the power factor correction chip U1' is electrically connected to the first ground terminal; capacitor C11' is connected between the COMP terminal and the INV terminal of the power factor correction chip U1'; capacitors C5' and resistor R6' connected in series are connected in parallel across capacitor C11'; the first terminal of diode D1' is electrically connected to the third terminal of transformer T, and the second terminal of diode D1' is electrically connected to the first ground terminal through resistors R5', R16' and R22'; capacitor C13' is connected in parallel across resistor R22', and the first terminal of capacitor C13' is electrically connected to the second terminal of capacitor C11';The resistor R23' is connected between the DRV terminal of the power factor correction chip U1' and the gate of the MOS transistor Q3'; the diode D4' and the resistor R18' connected in series are connected in parallel across both ends of the resistor R23'; the drain of the MOS transistor Q3' is connected between the third terminal of the transformer T and the first terminal of the diode D1', and the source of the MOS transistor Q3' is electrically connected to the first ground terminal through the resistor R33'; the first terminal of the resistor R27' is connected between the second terminal of the resistor R23' and the gate of the MOS transistor Q3', and the second terminal of the resistor R27' is connected between the second terminal of the resistor R29' and the first terminal of the resistor R33'; the first terminal of the resistor R29' is electrically connected to the CS terminal of the power factor correction chip U1'; the capacitor C18' is connected between the CS terminal of the power factor correction chip U1' and the first ground terminal; the capacitor C6' is connected between the second terminal of the diode D1' and the first ground terminal, and the first terminal of the capacitor C6' is connected to the voltage VBUS+.;

[0185] In the technical solution of this embodiment, by setting the power factor correction module 360, after the first AC voltage AC1 is converted into the first DC voltage DC1 by the rectifier bridge BD1', the power factor of the first DC voltage DC1 is corrected, the harmonic components are reduced, the power factor is improved, the energy consumption is reduced, and the external radiation and conduction interference of the power supply device are weakened.

[0186] On the basis of the above embodiments, Figure 14 is a schematic structural diagram of another LED dimming circuit provided by an embodiment of the present invention. As Figure 14 shown, optionally, the dimming circuit further includes a DC-AC conversion module 104, and the DC-AC conversion module 104 is used to invert the second DC voltage DC2 into a second AC voltage AC2, and the second AC voltage AC2 is used as the output voltage of the LED dimming circuit.

[0187] Among them, the DC-AC conversion module 104 includes a second DC voltage input terminal and a second AC voltage output terminal. The second DC voltage input terminal is connected to the second DC voltage DC2, the second AC voltage output terminal outputs the second AC voltage AC2, and the second DC voltage input terminal is electrically connected to the second DC voltage output terminal. The type of the transmission signal between the second DC voltage input terminal and the second DC voltage output terminal can be a level signal, and the embodiment of the present invention does not limit this. Exemplarily, the second AC voltage AC2 is an adjustable voltage; the effective value range of the voltage of the second AC voltage AC2 can be any voltage value within the range of [40, 125]; the frequency parameter of the second AC voltage AC2 can be any frequency value less than 1 kHz. It can be known that the voltage value of the second DC voltage DC2 can correspond one-to-one to the voltage value of the second AC voltage AC2.

[0188] It can be understood that the basic principle circuit of the DC-AC conversion module 104 can be any inverter circuit, and the embodiments of the present invention do not limit this, for example, it can be a semi-controlled inverter circuit or a fully controlled inverter circuit.

[0189] In the technical solution of this embodiment, by setting the DC-AC conversion module 104, after the DC-DC conversion module 103 converts the first DC voltage DC1 into the second DC voltage DC2, the second DC voltage DC2 is then inverted into the second AC voltage AC2, and the second AC voltage AC2 is used as the output voltage of the LED dimming circuit to match the specified brightness of the LED according to the magnitude of the second AC voltage AC2. The circuit provided in this embodiment is simple, low in cost, and easy to implement.

[0190] Based on the above embodiment, Figure 15 is a schematic structural diagram of a DC-AC conversion module provided by an embodiment of the present invention. As Figure 15 shown, optionally, the DC-AC conversion module 104 includes an inverter bridge unit 370 and an inverter drive unit 380. The inverter bridge unit 370 is used to couple the inverter drive signal and invert the second DC voltage DC2 into the second AC voltage AC2. The inverter drive unit 380 is used to couple the control signal and convert it into an inverter drive signal that can be used to drive the inverter bridge unit 370 to work.

[0191] Among them, the control signal is used to control the inverter drive unit 380 to generate an inverter drive signal; the inverter drive signal is used to control the inverter bridge unit 370 to invert the second DC voltage DC2 into the second AC voltage AC2. The inverter drive signal can be a pulse signal; the amplitude and frequency of the inverter drive signal can be adjusted accordingly according to actual needs, and the embodiments of the present invention do not limit this.

[0192] Continuing to refer to Figure 15 , optionally, the inverter bridge unit 370 includes a first bridge arm 371 and a second bridge arm 372. The first bridge arm 371 includes a first upper bridge arm 371A and a first lower bridge arm 371B, and the first upper bridge arm 371A and the first lower bridge arm 371B are used to couple the inverter drive signal and conduct alternately. The second bridge arm 372 includes a second upper bridge arm 372A and a second lower bridge arm 372B, and the second upper bridge arm 372A and the second lower bridge arm 372B are used to couple the inverter drive signal and conduct alternately.

[0193] Specifically, by way of example, the inverter bridge unit 370 further includes a diode D1". The first upper bridge arm 371A includes a resistor R43", a MOS transistor Q8", and a capacitor C33". The first lower bridge arm 371B includes a resistor R45", a MOS transistor Q9", and a capacitor C34". The second upper bridge arm 372A includes a resistor R40", a MOS transistor Q10", and a capacitor C31". The second lower bridge arm 372B includes a resistor R42", a MOS transistor Q11", and a capacitor C32". It can be known that the anode of the diode D1" is connected to the second DC voltage DC2, the cathode of the diode D1" is electrically connected to the drain of the MOS transistor Q8", the gate of the MOS transistor Q8" is electrically connected to the second end of the resistor R43", the capacitor C33" is connected in parallel between the drain and the source of the MOS transistor Q8", the drain of the MOS transistor Q9" is electrically connected to the source of the MOS transistor Q8", the source of the MOS transistor Q9" is electrically connected to the first ground terminal, the gate of the MOS transistor Q9" is electrically connected to the second end of the resistor R45", the capacitor C34" is connected in parallel between the source and the drain of the MOS transistor Q9", the drain of the MOS transistor Q10" is electrically connected to the drain of the MOS transistor Q8", the gate of the MOS transistor Q10" is electrically connected to the first end of the resistor R40", the source of the MOS transistor Q10" is electrically connected to the drain of the MOS transistor Q11", the capacitor C31" is connected in parallel between the source and the drain of the MOS transistor Q10", the source of the MOS transistor Q11" is electrically connected to the source of the MOS transistor Q9", the gate of the MOS transistor Q11" is electrically connected to the first end of the resistor R42", and the capacitor C32" is connected in parallel between the source and the drain of the MOS transistor Q11". In addition, the source of the MOS transistor Q8" serves as the first output terminal AC1" of the second AC voltage AC2, and the source of the MOS transistor Q10" serves as the second output terminal AC2" of the second AC voltage AC2.

[0194] In summary, the inverter bridge unit 370 is arranged in this way to realize the inversion of the second DC voltage DC2 into the second AC voltage AC2, and the circuit is stable and easy to implement.

[0195] Continue to refer to Figure 15 , optionally, the inverter drive unit 380 includes a first half-bridge drive circuit 381 and a second half-bridge drive circuit 382. The first half-bridge drive circuit 381 is used to couple a control signal to generate a first upper bridge arm drive signal and a first lower bridge arm drive signal. The first upper bridge arm drive signal is used to drive the first upper bridge arm 371A, and the first lower bridge arm drive signal is used to drive the first lower bridge arm 371B. The second half-bridge drive circuit 382 is used to couple a control signal to generate a second upper bridge arm drive signal and a second lower bridge arm drive signal. The second upper bridge arm drive signal is used to drive the second upper bridge arm 372A, and the second lower bridge arm drive signal is used to drive the second lower bridge arm 372B.

[0196] Specifically, by way of example, the first half-bridge drive circuit 381 includes a diode D15", a capacitor C28", a capacitor C30", a resistor R38", and a first half-bridge drive chip U3". It can be known that the anode of the diode D15" is electrically connected to the first power supply terminal, the cathode of the diode D15" is electrically connected to the VB terminal of the first half-bridge drive chip U3", the capacitor C30" is connected in parallel between the VB terminal and the VS terminal of the first half-bridge drive chip U3", the capacitor C28" is connected in series between the first power supply terminal and the first ground terminal, the first end of the resistor R38" is electrically connected to the HIN terminal and the LIN terminal of the first half-bridge drive chip U3 respectively, the second end of the resistor R38" is connected to the control signal AC_CON1, the COM terminal of the first half-bridge drive chip U3 is connected between the second end of the capacitor C28" and the first ground terminal, the VCC terminal of the first half-bridge drive chip U3 is connected between the first power supply terminal and the first end of the capacitor C28", the HO terminal of the first half-bridge drive chip U3 is electrically connected to the first end of the resistor R43", the VS terminal of the first half-bridge drive chip U3 is connected between the source electrode of the MOS transistor Q8" and the drain electrode of the MOS transistor Q9", and the LO terminal of the first half-bridge drive chip U3 is electrically connected to the first end of the resistor R45". It can be understood that the HO terminal of the first half-bridge drive chip U3 is used to output the first upper bridge arm drive signal, and the LO terminal of the first half-bridge drive chip U3 is used to output the first lower bridge arm drive signal.

[0197] In addition, by way of example, the second half-bridge drive circuit 382 includes a diode D14", a capacitor C27", a capacitor C29", a resistor R36", and a second half-bridge drive chip U4". It can be known that the anode of the diode D14" is electrically connected to the first power supply terminal, the cathode of the diode D14" is electrically connected to the VB terminal of the second half-bridge drive chip U4", the capacitor C29" is connected in parallel between the VB terminal and the VS terminal of the second half-bridge drive chip U4", the capacitor C27" is connected in series between the first power supply terminal and the first ground terminal, the first end of the resistor R36" is electrically connected to the HIN terminal and the LIN terminal of the second half-bridge drive chip U4 respectively, the second end of the resistor R36" is connected to the control signal AC_CON2, the COM terminal of the second half-bridge drive chip U4 is connected between the second end of the capacitor C27" and the first ground terminal, the VCC terminal of the second half-bridge drive chip U4 is connected between the first power supply terminal and the first end of the capacitor C27", the HO terminal of the second half-bridge drive chip U4 is electrically connected to the second end of the resistor R40", the VS terminal of the second half-bridge drive chip U4 is connected between the source electrode of the MOS transistor Q10" and the drain electrode of the MOS transistor Q11", and the LO terminal of the second half-bridge drive chip U4 is electrically connected to the second end of the resistor R42". It can be understood that the HO terminal of the second half-bridge drive chip U4 is used to output the second upper bridge arm drive signal, and the LO terminal of the second half-bridge drive chip U4 is used to output the second lower bridge arm drive signal.

[0198] It can be seen that, in the technical solution of this embodiment, by providing the inverter bridge unit 370 and the inverter drive unit 380, the second DC voltage DC2 is inverted into the second AC voltage AC2. Moreover, this embodiment provides the specific circuit structures of the inverter bridge unit 370 and the inverter drive unit 380, and their circuit structures are simple and easy to implement.

[0199] It should be noted that the specific models and characteristic parameters of the various electronic components used to form the dimming circuit are all related to the dimming effect to be achieved by the dimming circuit, and the embodiments of the present invention do not limit them. Exemplarily, each of the above resistors can be a surface mount resistor.

[0200] The embodiments of the present invention also provide an LED dimmer. The LED dimmer provided by the embodiments of the present invention includes the LED dimming circuit provided by any embodiment of the present invention, and its technical principle and achieved effect are similar, so details will not be described again.

[0201] The embodiments of the present invention also provide an LED lighting device. The LED lighting device provided by the embodiments of the present invention includes the LED dimmer provided by any embodiment of the present invention, and its technical principle and achieved effect are similar, so details will not be described again. Exemplarily, the LED lighting device can be of Type B.

[0202] Note that the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here, and various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An LED dimming circuit, characterized in that, Comprising: An AC-DC conversion module for converting a first AC voltage into a first DC voltage; wherein, the first AC voltage is the input AC voltage; A DC-DC conversion module for converting the first DC voltage into a second DC voltage; wherein, the voltage magnitude of the second DC voltage matches the specified brightness of the LED; A dimming instruction transmission module for coupling a dimming instruction, generating a control signal for controlling the DC-DC conversion module according to the dimming instruction, so as to transmit the dimming instruction; The DC-DC conversion module includes: A first transformer, the first transformer includes a primary winding and a secondary winding, the primary winding is used for accessing the first DC voltage, and the secondary winding is used for outputting the second DC voltage; A feedback unit, the feedback unit is connected in series between the primary winding and a first ground terminal, and the feedback unit is used for receiving the dimming instruction and controlling the on-off between the primary winding and the first ground terminal accordingly; It further includes a first optocoupler; the feedback unit and the dimming instruction transmission module perform the transmission of the dimming instruction through the first optocoupler; The dimming instruction transmission module includes: A first comparator, a first input terminal of the first comparator accesses the dimming instruction, and a second input terminal of the first comparator accesses a comparison voltage signal; The light emitter in the first optocoupler is connected in series between the output terminal of the first comparator and a first power supply terminal.

2. The dimming circuit according to claim 1, wherein The first AC voltage is an adjustable voltage; correspondingly, the first DC voltage is an adjustable voltage; the voltage value of the first DC voltage corresponds one-to-one with the voltage value of the first AC voltage.

3. The dimming circuit according to claim 1, wherein The feedback unit includes: A feedback control chip, the feedback control chip includes a feedback pin and a gate drive output pin; A first transistor, the first transistor is connected in series between the primary winding and the first ground terminal, and the gate of the first transistor is electrically connected to the gate drive output pin; The light receiver in the first optocoupler is connected in series between the feedback pin and the first ground terminal.

4. The dimming circuit according to claim 1, wherein The DC-DC conversion module further includes: A first inductor, the first inductor is connected in series between the AC-DC conversion module and the primary winding; wherein, the first inductor is electrically connected to the first end of the primary winding; A first resistor, the first resistor is connected in parallel with the first inductor; A first capacitor, a first end of the first capacitor is electrically connected to a first end of the first resistor, and a second end of the first capacitor is electrically connected to the first ground terminal; A second capacitor, a first end of the second capacitor is electrically connected to a second end of the first resistor, and a second end of the second capacitor is electrically connected to the first ground terminal; A first varistor, the first varistor is connected in parallel with the second capacitor; A third capacitor, a first end of the third capacitor is electrically connected to a first end of the second capacitor; A first diode, a cathode of the first diode is electrically connected to a second end of the third capacitor, and an anode of the first diode is electrically connected to a second end of the primary winding; A second resistor, the second resistor being connected in parallel with the third capacitor.

5. The dimming circuit according to claim 1, wherein The DC-DC conversion module further includes: A third resistor, a first end of the third resistor being electrically connected to a first end of the secondary winding; A fourth capacitor, a first end of the fourth capacitor being electrically connected to a second end of the third resistor, and a second end of the fourth capacitor serving as a first output end of the dimming circuit; A second diode, a first end of the second diode being electrically connected to a first end of the secondary winding, and a second end of the second diode being electrically connected to the first output end of the dimming circuit; A fifth capacitor, a first end of the fifth capacitor being electrically connected to the first output end of the dimming circuit, a second end of the fifth capacitor being electrically connected to a second end of the secondary winding and being electrically connected to a second grounding end; A fourth resistor, the fourth resistor being connected in parallel with the fifth capacitor; A fifth resistor, a first end of the fifth resistor being electrically connected to a second end of the secondary winding, and a second end of the fifth resistor being electrically connected to a second output end of the dimming circuit; A third diode, an anode of the third diode being electrically connected to the second output end of the dimming circuit, and a cathode of the third diode being electrically connected to a second end of the secondary winding.

6. The dimming circuit according to claim 5, wherein It further includes: A current detection module, the current detection module being electrically connected to the second output end of the dimming circuit, and the current detection module being configured to detect the current at the second output end.

7. The dimming circuit according to claim 6, characterized in that, The current detection module includes: A fifth comparator, the fifth comparator including a first input terminal, a second input terminal, and an output terminal; An eighth resistor, a first end of the eighth resistor being electrically connected to the second output end of the dimming circuit; A ninth resistor, a first end of the ninth resistor being electrically connected to a second end of the eighth resistor, and a second end of the ninth resistor being electrically connected to the first input terminal of the fifth comparator; A tenth resistor, a first end of the tenth resistor being electrically connected to a second grounding end, and a second end of the tenth resistor being electrically connected to the first input terminal of the fifth comparator; An eleventh resistor, a first end of the eleventh resistor being electrically connected to the second grounding end; A twelfth resistor, a first end of the twelfth resistor being electrically connected to a second end of the eleventh resistor; a second end of the twelfth resistor being electrically connected to the second input terminal of the fifth comparator; A thirteenth resistor, a first end of the thirteenth resistor being electrically connected to a second end of the twelfth resistor; a second end of the thirteenth resistor being electrically connected to the output terminal of the fifth comparator; A seventh capacitor, a first end of the seventh capacitor being electrically connected to a first end of the tenth resistor, and a second end of the seventh capacitor being electrically connected to a first end of the twelfth resistor; A fourteenth resistor, a first end of the fourteenth resistor being electrically connected to the output terminal of the fifth comparator, and a second end of the fourteenth resistor serving as an output end of the current detection module; An eighth capacitor, a first end of the eighth capacitor being electrically connected to a second end of the fourteenth resistor, and a second end of the eighth capacitor being electrically connected to the second grounding end.

8. The dimming circuit according to claim 6, wherein The current detection module includes: A sixth comparator, the sixth comparator including a first input terminal, a second input terminal, and an output terminal; The fifteenth resistor, the first end of the fifteenth resistor is electrically connected to the second output end of the dimming circuit, and the second end of the fifteenth resistor is electrically connected to the first input end of the sixth comparator; The ninth capacitor, the first end of the ninth capacitor is electrically connected to the first input end of the sixth comparator, and the second end of the ninth capacitor is electrically connected to the second input end of the sixth comparator; The sixteenth resistor, the first end of the sixteenth resistor is connected to a comparison voltage signal, and the second end of the sixteenth resistor is electrically connected to the second input end of the sixth comparator; The seventeenth resistor, the first end of the seventeenth resistor is electrically connected to the output end of the sixth comparator, and the second end of the seventeenth resistor serves as the output end of the current detection module; The tenth capacitor, the first end of the tenth capacitor is electrically connected to the output end of the current detection module, and the second end of the tenth capacitor is electrically connected to the second output end of the dimming circuit.

9. The dimming circuit according to claim 1, wherein The AC-DC conversion module includes: An electromagnetic compatibility unit for anti-electromagnetic interference and transmitting the filtered first AC voltage to the subsequent circuit; A rectifier bridge for converting the filtered first AC voltage into the first DC voltage.

10. The dimming circuit according to claim 1, wherein It further includes: A power factor correction module connected between the AC-DC conversion module and the DC-DC conversion module; the power factor correction module is used to perform power factor correction on the first DC voltage and then transmit it to the DC-DC conversion module.

11. The dimming circuit according to claim 1, wherein It further includes: A DC-AC conversion module for inverting the second DC voltage into a second AC voltage, and the second AC voltage serves as the output voltage of the LED dimming circuit.

12. The dimming circuit according to claim 11, wherein The DC-AC conversion module includes: An inverter bridge unit for coupling an inverter drive signal and inverting the second DC voltage into the second AC voltage; An inverter drive unit for coupling a control signal and converting it into the inverter drive signal that can be used to drive the inverter bridge unit to work.

13. The dimming circuit according to claim 12, wherein The inverter bridge unit includes: The first bridge arm, the first bridge arm includes a first upper bridge arm and a first lower bridge arm, and the first upper bridge arm and the first lower bridge arm are used to couple the inverter drive signal and conduct alternately; The second bridge arm, the second bridge arm includes a second upper bridge arm and a second lower bridge arm, and the second upper bridge arm and the second lower bridge arm are used to couple the inverter drive signal and conduct alternately.

14. The dimming circuit according to claim 12, characterized in that, The inverter drive unit includes: The first half-bridge drive circuit for coupling the control signal to generate a first upper bridge arm drive signal and a first lower bridge arm drive signal, the first upper bridge arm drive signal is used to drive the first upper bridge arm, and the first lower bridge arm drive signal is used to drive the first lower bridge arm; The second half-bridge drive circuit for coupling the control signal to generate a second upper bridge arm drive signal and a second lower bridge arm drive signal, the second upper bridge arm drive signal is used to drive the second upper bridge arm, and the second lower bridge arm drive signal is used to drive the second lower bridge arm.

15. An LED dimming circuit, characterized in that, It includes: An AC-DC conversion module for converting a first AC voltage into a first DC voltage; wherein, the first AC voltage is the input AC voltage; A DC-DC conversion module for converting the first DC voltage into a second DC voltage, wherein the magnitude of the second DC voltage matches the specified brightness of the LED. A dimming instruction transmission module for coupling a dimming instruction, generating a control signal for controlling the DC-DC conversion module according to the dimming instruction, and transmitting the dimming instruction. The DC-DC conversion module includes: A second transformer, which includes a primary side winding and two secondary side windings connected in series. The connection point of the two secondary side windings is defined as an output node, and the two ends different from the output node in the two secondary side windings are respectively a first end and a second end. A first switch unit, which is connected in series between the output end of the AC-DC conversion module and the primary side winding. A second switch unit, which is connected in parallel with the primary side winding. A first control unit for receiving the dimming instruction and controlling the on / off of the first switch unit and the second switch unit accordingly. A third switch unit, which is connected in series between the first end of the secondary side winding and the first voltage terminal. A fourth switch unit, which is connected in series between the second end of the secondary side winding and the second voltage terminal. A second control unit for controlling the on / off of the third switch unit and the fourth switch unit. Wherein, the output node is electrically connected to the first output end of the dimming circuit, and the second voltage terminal is electrically connected to the second output end of the dimming circuit.

16. The dimming circuit according to claim 15, wherein, It further includes: A second optocoupler; the first control unit and the dimming instruction transmission module transmit the dimming instruction through the second optocoupler.

17. The dimming circuit according to claim 16, characterized in that, The dimming instruction transmission module includes: A third comparator, the first input terminal of which receives the dimming instruction, and the second input terminal of which receives a comparison voltage signal. A fourth comparator, the first terminal of which is electrically connected to the second ground terminal, and the second terminal of which receives the comparison voltage signal. The light emitter in the second optocoupler is connected in series between the output terminal of the third comparator and the first power supply terminal; the output terminal of the fourth comparator is electrically connected to the output terminal of the third comparator.

18. The dimming circuit according to claim 16, wherein The first control unit includes: A resonant control chip, which includes a resonant control pin, a first gate drive output pin, and a second gate drive output pin. The light receiver in the second optocoupler is connected in series between the resonant control pin and the first ground terminal; the first gate drive output pin is electrically connected to the first switch unit, and the second gate drive output pin is electrically connected to the second switch unit.

19. The dimming circuit according to claim 16, wherein The second control unit includes: An LLC synchronous rectifier, which includes a first voltage pin, a second voltage pin, a third voltage pin, a fourth voltage pin, a third gate drive pin, and a fourth gate drive pin. The first voltage pin is connected to a second voltage signal. The second voltage pin is electrically connected to the first voltage terminal and is also electrically connected to the second voltage terminal. The third voltage pin is electrically connected to the first end of the secondary winding, and the fourth voltage pin is electrically connected to the second end of the secondary winding. The third gate drive pin is electrically connected to the third switching unit, and the fourth gate drive pin is electrically connected to the fourth switching unit.

20. The dimming circuit according to claim 15, wherein The DC-DC conversion module further includes: A second inductor, which is connected in series between the first switching unit and the primary winding.

21. The dimming circuit according to claim 15, wherein, The DC-DC conversion module further includes: A sixth resistor, which is connected in series between the third switching unit and the second output terminal of the dimming circuit. A seventh resistor, the first end of which is electrically connected to the first output terminal of the dimming circuit, and the second end of which is electrically connected to the third switching unit. A sixth capacitor, which is connected in parallel with the seventh resistor.

22. The dimming circuit according to claim 15, characterized in that, It further includes: A current detection module, which is electrically connected to the second output terminal of the dimming circuit and is used to detect the current at the second output terminal.

23. The dimming circuit according to claim 22, wherein The current detection module includes: A fifth comparator, which includes a first input terminal, a second input terminal, and an output terminal. An eighth resistor, the first end of which is electrically connected to the second output terminal of the dimming circuit. A ninth resistor, the first end of which is electrically connected to the second end of the eighth resistor, and the second end of which is electrically connected to the first input terminal of the fifth comparator. A tenth resistor, the first end of which is electrically connected to the second ground terminal, and the second end of which is electrically connected to the first input terminal of the fifth comparator. An eleventh resistor, the first end of which is electrically connected to the second ground terminal. A twelfth resistor, the first end of which is electrically connected to the second end of the eleventh resistor, and the second end of which is electrically connected to the second input terminal of the fifth comparator. A thirteenth resistor, the first end of which is electrically connected to the second end of the twelfth resistor, and the second end of which is electrically connected to the output terminal of the fifth comparator. A seventh capacitor, the first end of which is electrically connected to the first end of the tenth resistor, and the second end of which is electrically connected to the first end of the twelfth resistor. A fourteenth resistor, the first end of which is electrically connected to the output terminal of the fifth comparator, and the second end of which serves as the output terminal of the current detection module. An eighth capacitor, the first end of which is electrically connected to the second end of the fourteenth resistor, and the second end of which is electrically connected to the second ground terminal.

24. The dimming circuit according to claim 22, characterized in that, The current detection module includes: A sixth comparator, which includes a first input terminal, a second input terminal, and an output terminal. The fifteenth resistor, the first end of the fifteenth resistor is electrically connected to the second output end of the dimming circuit, and the second end of the fifteenth resistor is electrically connected to the first input end of the sixth comparator; The ninth capacitor, the first end of the ninth capacitor is electrically connected to the first input end of the sixth comparator, and the second end of the ninth capacitor is electrically connected to the second input end of the sixth comparator; The sixteenth resistor, the first end of the sixteenth resistor is connected to a comparison voltage signal, and the second end of the sixteenth resistor is electrically connected to the second input end of the sixth comparator; The seventeenth resistor, the first end of the seventeenth resistor is electrically connected to the output end of the sixth comparator, and the second end of the seventeenth resistor serves as the output end of the current detection module; The tenth capacitor, the first end of the tenth capacitor is electrically connected to the output end of the current detection module, and the second end of the tenth capacitor is electrically connected to the second output end of the dimming circuit.

25. The dimming circuit according to claim 15, characterized in that, The AC-DC conversion module includes: An electromagnetic compatibility unit for anti-electromagnetic interference and transmitting the filtered first AC voltage to the subsequent circuit; A rectifier bridge for converting the filtered first AC voltage into the first DC voltage.

26. The dimming circuit according to claim 15, wherein It further includes: A power factor correction module connected between the AC-DC conversion module and the DC-DC conversion module; the power factor correction module is used to perform power factor correction on the first DC voltage and then transmit it to the DC-DC conversion module.

27. The dimming circuit according to claim 15, characterized in that, It further includes: A DC-AC conversion module for inverting the second DC voltage into a second AC voltage, and the second AC voltage serves as the output voltage of the LED dimming circuit.

28. The dimming circuit according to claim 27, wherein The DC-AC conversion module includes: An inverter bridge unit for coupling an inverter drive signal and inverting the second DC voltage into the second AC voltage; An inverter drive unit for coupling a control signal and converting it into the inverter drive signal that can be used to drive the inverter bridge unit to work.

29. The dimming circuit according to claim 28, wherein The inverter bridge unit includes: The first bridge arm, the first bridge arm includes a first upper bridge arm and a first lower bridge arm, and the first upper bridge arm and the first lower bridge arm are used to couple the inverter drive signal and conduct alternately; The second bridge arm, the second bridge arm includes a second upper bridge arm and a second lower bridge arm, and the second upper bridge arm and the second lower bridge arm are used to couple the inverter drive signal and conduct alternately.

30. The dimming circuit according to claim 28, characterized in that, The inverter drive unit includes: A first half-bridge drive circuit for coupling the control signal to generate a first upper bridge arm drive signal and a first lower bridge arm drive signal, the first upper bridge arm drive signal is used to drive the first upper bridge arm, and the first lower bridge arm drive signal is used to drive the first lower bridge arm; A second half-bridge drive circuit for coupling the control signal to generate a second upper bridge arm drive signal and a second lower bridge arm drive signal, the second upper bridge arm drive signal is used to drive the second upper bridge arm, and the second lower bridge arm drive signal is used to drive the second lower bridge arm.

31. An LED dimmer, characterized in that, It includes: The dimming circuit according to any one of claims 1-30.

32. An LED lighting device, characterized in that, It includes: The LED dimmer according to claim 31.

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