Adjustable optical communication single-stage resonance type LED drive circuit

Abstract

The invention discloses an adjustable optical communication single-stage resonance type LED drive circuit which comprises an LED drive circuit, the LED drive circuit comprises a drive protection circuit, a voltage sampling circuit and a current sampling circuit, and the voltage sampling circuit and the current sampling circuit are both connected with the drive protection circuit. The PFC unit in the driving protection circuit adopts a bridgeless Boost circuit to reduce conduction loss; the DC-DC unit adopts an LLC resonance circuit to reduce switching loss, two-stage circuits are integrated into a single-stage circuit through multiplexing of double-unit switching tubes, the number of the switching tubes and the number of control circuits are reduced, a control system is simplified, and cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of LED drive circuits, and in particular to an adjustable optical communication single-stage resonant LED drive circuit. Background Art

[0002] LED has the advantages of low power consumption, high brightness, long life, small size, good dimming and no pollution, and is widely used in lighting occasions. It is known as the fourth generation of green electric light source. In addition, the visible light communication technology is derived from the characteristics of LED's good modulation and fast response speed, making it possible for LED to achieve dual functions of communication and lighting. With the rapid development of LED, LED driving circuit has also become a research hotspot in the industry.

[0003] At present, most LED drive circuits adopt a two-stage structure. The front-stage PFC circuit usually adopts a Boost circuit to achieve power factor correction, and the rear-stage DC-DC circuit usually adopts a Flyback circuit or an LLC circuit to achieve constant current output according to the power level. In this two-stage LED drive circuit, the front-stage PFC circuit has an independent control circuit, which can ensure good input characteristics and provide a constant input voltage for the rear-stage DC-DC circuit. For the rear-stage DC-DC circuit, the constant input voltage is conducive to the parameter design of the circuit, the design of magnetic devices and the improvement of efficiency, especially the LLC circuit. In addition, the rear-stage DC-DC circuit also adopts an independent control circuit to achieve constant current drive of the LED through closed-loop feedback control of the output current. In order to improve the efficiency of the rear-stage DC-DC circuit, the application of soft switching technology has also become a hot spot. For example, a quasi-resonant working mode is proposed for the Flyback circuit, and the MOS tube is turned on at the bottom of the resonant voltage to reduce the switching loss; and the LLC circuit itself, as a kind of multi-resonant converter, can automatically realize the zero voltage turn-on of the primary MOS tube and the zero current turn-off of the secondary rectifier diode, so it has been widely used in the industry.

[0004] However, the traditional LED driving circuit has the following disadvantages:

[0005] The traditional LED driving circuit has two sets of control circuits, resulting in high cost, low reliability and complex control. Summary of the invention

[0006] The purpose of the present invention is to provide a single-stage resonant LED driving circuit for adjustable optical communication to solve the problems of high cost, low reliability and complex control caused by two sets of control circuits of the traditional LED driving circuit proposed in the above background technology.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an adjustable optical communication single-stage resonant LED driving circuit, comprising an LED driving circuit, wherein the LED driving circuit comprises a driving protection circuit, a voltage sampling circuit and a current sampling circuit, wherein the voltage sampling circuit and the current sampling circuit are both connected to the driving protection circuit, and the driving protection circuit comprises a pulse signal input port PWMIN, an input and output port GPIO, a variable resistor R1, a resistor R2, a transistor T, an amplifier MC74VHG, a resistor R3, a resistor R4, an optocoupler HCPL3120, a power module QA02, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, and a diode D 1 and a pulse signal output port PWM output OUT, the voltage sampling circuit includes an input IN, a diode D1, a variable resistor R1, a resistor R2, a resistor R3, an input resistor Rin, a resistor R4, a resistor R5, a current sensor AMC1200, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a diode D2, a diode D3, an amplifier U2 and an output OUT, the current sampling circuit includes a linear current sensor ACS712, an LED, a feedback capacitor Cf, a variable resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C1, a capacitor C2, a capacitor C3, a diode D1, a diode D2 and an operational amplifier LM358.

[0008] As a preferred technical solution of the present invention, the ENB end pin of the amplifier MC74VHG is connected to one end of the resistor R2, the IN end pin of the amplifier MC74VHG is respectively connected to one end of the resistor R3 and one end of the pulse signal input port PWMIN, the resistor R3 and the amplifier MC74VHG are respectively connected to the emitter and collector of the transistor T, the base of the transistor T is connected to one end of the variable resistor R1, the other end of the variable resistor R1 is connected to one end of the input and output port GPIO, the output OUT end pin of the amplifier MC74VHG is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the 2 end pin of the photoelectric coupler HCPL3120, the 7 end pin of the photoelectric coupler HCPL3120 is connected to one end of the resistor R5, the 6 end pin of the photoelectric coupler HCPL3120 is connected to one end of the resistor R6, and the other end of the resistor R5 is connected to one end of the diode D1. The other end of the diode D1 and the other end of the resistor R6 are both connected to one end of the pulse signal output port PWM output OUT, and the other end of the pulse signal output port PWM output OUT is respectively connected to one end of the resistor R7, one end of the capacitor C3, one end of the capacitor C4, one end of the resistor R8, one end of the capacitor C1, one end of the capacitor C2 and the 6th pin of the power module QA02, the other end of the resistor R7, the other end of the capacitor C3 and the other end of the capacitor C1 are all connected to the 7th pin of the power module QA02, the other end of the resistor R8, the other end of the capacitor C4 and the other end of the capacitor C2 are all connected to the 5th pin of the power module QA02, and the 2nd pin of the power module QA02, the 1st pin of the photoelectric coupler HCPL3120, the 3rd pin of the photoelectric coupler HCPL3120, the 4th pin of the photoelectric coupler HCPL3120, the emitter of the transistor T and the input end of the pulse signal input port PWMIN are all grounded.

[0009] As a preferred technical solution of the present invention, the end pin 1 of the input IN is connected to one end of the input resistor Rin, the other end of the input resistor Rin is connected to one end of the variable resistor R1, the other end of the variable resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the 2 end pins of the input IN, the variable resistor R1 and the resistor R2 are connected to one end of the diode D1, the connection between the resistor R3 and the input IN is connected to the other end of the diode D1, the connection between the resistor R2 and the resistor R3 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the 2 end pins of the current sensor AMC1200, and the 3 end pins of the current sensor AMC1200 are connected to the resistor R 5, the resistor R4 and the resistor R5 are connected in parallel with the capacitor C1, the 7-pin of the current sensor AMC1200 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to one end of the resistor R7 and the 3-pin of the amplifier U2, the 6-pin of the current sensor AMC1200 is connected to one end of the resistor R8, the other end of the resistor R8 is respectively connected to the 2-pin of the amplifier U2 and one end of the resistor R9, the other end of the resistor R9 and the 1-pin of the amplifier U2 are both connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to one end of the capacitor C2 and the 1-pin of the output OUT, the other end of the capacitor C2 is connected to one end of the diode D3, and the other end of the diode D3 is connected to one end of the diode D2.

[0010] As a preferred technical solution of the present invention, the IP+ terminal pin of the linear current sensor ACS712 is connected to one end of the LED, the output OUT terminal pin of the linear current sensor ACS712 is connected to one end of the resistor R4, the other end of the resistor R4 is respectively connected to one end of the resistor R5 and one end of the capacitor C1, the other end of the resistor R5 is connected to the positive electrode of the operational amplifier LM358, the connection point between the resistor R5 and the operational amplifier LM358 is connected to one end of the resistor R6, the negative electrode of the operational amplifier LM358 is respectively connected to one end of the resistor R3 and one end of the resistor R7, the other end of the resistor R3 is respectively connected to one end of the variable resistor R1 and one end of the resistor R2, the FILTER terminal pin of the linear current sensor ACS712 is connected to one end of the feedback capacitor Cf, the other end of the resistor R7 is connected in parallel with the capacitor C2, the surface of the operational amplifier LM358 is connected to one end of the resistor R8, and the other end of the resistor R8 is respectively connected to one end of the capacitor C3, one end of the diode D1 and one end of the diode D2.

[0011] Compared with the prior art, the beneficial effects of the present invention are: the PFC unit in the drive protection circuit adopts a bridgeless Boost circuit to reduce conduction loss; the DC-DC unit adopts an LLC resonant circuit to reduce switching loss, and the two-stage circuit is integrated into a single-stage circuit through the reuse of dual-unit switching tubes, thereby reducing the number of switching tubes and control circuits, simplifying the control system and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a physical diagram of the present invention;

[0013] Figure 2 It is a schematic diagram of the structure of the LED driving circuit of the present invention;

[0014] Figure 3 A schematic diagram of the structure of the driving protection circuit of the present invention;

[0015] Figure 4 is a circuit diagram of a voltage sampling circuit of the present invention;

[0016] Figure 5 is a circuit diagram of a current sampling circuit of the present invention;

[0017] Figure 6 1 is a waveform diagram of the inductor current under different input voltages of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] See also Figure 1-6The present invention provides an adjustable optical communication single-stage resonant LED driving circuit, including an LED driving circuit, the LED driving circuit including a driving protection circuit, a voltage sampling circuit and a current sampling circuit, the voltage sampling circuit and the current sampling circuit are both connected to the driving protection circuit, the driving protection circuit includes a pulse signal input port PWMIN, an input and output port GPIO, a variable resistor R1, a resistor R2, a transistor T, an amplifier MC74VHG, a resistor R3, a resistor R4, an optocoupler HCPL3120, a power module QA02, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a diode D1 and a pulse signal input The output port PWM output OUT, the voltage sampling circuit includes input IN, diode D1, variable resistor R1, resistor R2, resistor R3, input resistor Rin, resistor R4, resistor R5, current sensor AMC1200, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, diode D2, diode D3, amplifier U2 and output OUT, the current sampling circuit includes linear current sensor ACS712, LED, feedback capacitor Cf, variable resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, capacitor C1, capacitor C2, capacitor C3, diode D1, diode D2 and operational amplifier LM358.

[0020] The ENB pin of the amplifier MC74VHG is connected to one end of the resistor R2, the IN pin of the amplifier MC74VHG is respectively connected to one end of the resistor R3 and one end of the pulse signal input port PWMIN, the resistor R3 and the amplifier MC74VHG are respectively connected to the emitter and collector of the transistor T, the base of the transistor T is connected to one end of the variable resistor R1, the other end of the variable resistor R1 is connected to one end of the input and output port GPIO, the output OUT pin of the amplifier MC74VHG is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the 2 end pin of the photocoupler HCPL3120, the 7 end pin of the photocoupler HCPL3120 is connected to one end of the resistor R5, the 6 end pin of the photocoupler HCPL3120 is connected to one end of the resistor R6, the other end of the resistor R5 is connected to one end of the diode D1, the other end of the diode D1 and the resistor The other end of R6 is connected to one end of the pulse signal output port PWM output OUT, and the other end of the pulse signal output port PWM output OUT is respectively connected to one end of the resistor R7, one end of the capacitor C3, one end of the capacitor C4, one end of the resistor R8, one end of the capacitor C1, one end of the capacitor C2 and the 6th pin of the power module QA02, the other end of the resistor R7, the other end of the capacitor C3 and the other end of the capacitor C1 are all connected to the 7th pin of the power module QA02, the other end of the resistor R8, the other end of the capacitor C4 and the other end of the capacitor C2 are all connected to the 5th pin of the power module QA02, the 2nd pin of the power module QA02, the 1st pin of the photoelectric coupler HCPL3120, the 3rd pin of the photoelectric coupler HCPL3120, the 4th pin of the photoelectric coupler HCPL3120, the emitter of the transistor T and the input end of the pulse signal input port PWMIN are all grounded.

[0021] The pin 1 of the input IN is connected to one end of the input resistor Rin, the other end of the input resistor Rin is connected to one end of the variable resistor R1, the other end of the variable resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the pin 2 of the input IN, the variable resistor R1, the resistor R2 and one end of the diode D1 are connected, the connection point of the resistor R3 and the input IN is connected to the other end of the diode D1, the connection point of the resistor R2 and the resistor R3 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the pin 2 of the current sensor AMC1200, the pin 3 of the current sensor AMC1200 is connected to one end of the resistor R5, and the resistor R4 is connected in parallel with the resistor R5 with the capacitor C1, the 7-pin of the current sensor AMC1200 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to one end of the resistor R7 and the 3-pin of the amplifier U2, the 6-pin of the current sensor AMC1200 is connected to one end of the resistor R8, the other end of the resistor R8 is respectively connected to the 2-pin of the amplifier U2 and one end of the resistor R9, the other end of the resistor R9 and the 1-pin of the amplifier U2 are both connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to one end of the capacitor C2 and the 1-pin of the output OUT, the other end of the capacitor C2 is connected to one end of the diode D3, and the other end of the diode D3 is connected to one end of the diode D2.

[0022] The IP+ terminal of the linear current sensor ACS712 is connected to one end of the LED, the output OUT terminal of the linear current sensor ACS712 is connected to one end of the resistor R4, the other end of the resistor R4 is respectively connected to one end of the resistor R5 and one end of the capacitor C1, the other end of the resistor R5 is connected to the positive electrode of the operational amplifier LM358, the connection point between the resistor R5 and the operational amplifier LM358 is connected to one end of the resistor R6, the negative electrode of the operational amplifier LM358 is respectively connected to one end of the resistor R3 and one end of the resistor R7, the other end of the resistor R3 is respectively connected to one end of the variable resistor R1 and one end of the resistor R2, the FILTER terminal of the linear current sensor ACS712 is connected to one end of the feedback capacitor Cf, the other end of the resistor R7 is connected in parallel with the capacitor C2, the surface of the operational amplifier LM358 is connected to one end of the resistor R8, and the other end of the resistor R8 is respectively connected to one end of the capacitor C3, one end of the diode D1 and one end of the diode D2.

[0023] In the present invention, in conjunction with the specification Figure 1, AC input voltage effective value range, 90-135Vrms; rated input voltage effective value, 110Vrms; rated output current, 2A; load range, 80-100W; resonant frequency, fr=100kHz, fr1=45kHz; overall efficiency, >90%, full load, rated input voltage; power factor, >0.95, full load, full input voltage range;

[0024] In conjunction with the instruction manual Figure 2 -,

[0025] Design input voltage 120V ms When the circuit works at the resonance point f r , at this time, the DC gain of LLC is M dc is 1, then the turns ratio is:

[0026]

[0027] The voltage stress across the resonant capacitor is:

[0028]

[0029] In the formula, f s-min is the minimum switching frequency; C r is the resonant capacitor. The value of the resonant capacitor should be such that the resonant capacitor C r The voltage stress is less than the withstand voltage of the resonant capacitor, and the selected resonant capacitor capacity C r =12nF, 630V withstand voltage; at resonant frequency f r With the resonant capacitor C r The determined case is small, and the resonant inductance value is based on the formula:

[0030]

[0031] The maximum peak current flowing through the Boost core is:

[0032]

[0033] Where V in-min is the minimum input voltage effective value, take 90V, D max is the maximum duty cycle of the multiplexed MOS tube S2, which is 0.5, f s-min For the lowest switching frequency, take 60kHZ, the number of turns required for the Boost inductor is:

[0034]

[0035] When actually winding, the number of inductor turns is 29, and the air gap length required for air gap length calculation is:

[0036]

[0037] Where μ0 is the vacuum magnetic permeability, μ0=4πx10 -7 H / m,

[0038] Selection of MOS tubes S1 and S2 According to the previous theoretical analysis and simulation, the DC bus voltage is no more than 450V, and the voltage stress of MOS tubes S1 and S2 is proportional to the DC bus voltage V bus Similarly, in order to leave a certain safety margin, a 600V or 650V withstand voltage MOS tube is required. Only LLC resonant current flows through MOS tube S1, and the current flowing through MOS tube S2 is the sum of the resonant current and the Boost inductor current. Therefore, the current stress of MOS tube S1 is 1.027A, and the current stress of MOS tube S2 is 5.428A. In the experiment, MOS tubes S1 and S2 both use SV diodes D10N65T;

[0039] In conjunction with the instruction manual Figure 3 The drive protection circuit is divided into two parts: a buffer protection circuit and an isolation drive circuit. The main working principle of the buffer protection circuit is: when the DSP does not detect circuit abnormality, the GPIO pin of the input and output port outputs a low level. At this time, the transistor T is cut off, the buffer MC74VH capacitor C1GT125 diode D1 is in the enabled state, and the PWM signal generated by the DSP is input to the optocoupler through the buffer; when the DSP detects circuit abnormality, the GPIO pin of the input and output port outputs a high ... The 125 diode D1 is in a non-enabled state and does not output a PWM signal. The isolation drive circuit is mainly composed of an optocoupler HCPL3120 and an isolation power supply module QA02. The optocoupler HCPL3120 withstands a withstand voltage of 15kV and the drive current is only 5mA. The isolation power supply module QA02 provides +15V and -8V positive and negative levels for the optocoupler HCPL3120. Therefore, the isolation drive circuit realizes a high level +15V and a low level -8V drive waveform, thereby ensuring that the MOS tube is turned on and off.

[0040] In conjunction with the instruction manual Figure 4,Since the sampled DC bus voltage signal needs to be sent to DSP, in order to protect the DSP chip, the voltage sampling circuit must use an isolation amplifier to isolate the main circuit from the control circuit. The isolation amplifier used is the current sensor AMC1200, which has an input voltage range of +250mV, a minimum input bandwidth of 50KHz, and a maximum withstand voltage of 4000V. In order to suppress noise and improve the circuit's anti-interference ability, a differential amplifier circuit is added after the isolation amplifier. In addition, the sampled voltage signal needs to be sent to the ADC module of the DSP. In order to prevent the voltage sampling circuit from outputting overvoltage and breaking down the DSP, a diode phase circuit is added to the output end of the voltage sampling circuit. When the output is overvoltage, it is limited to 3.3V, thereby protecting the DSP;

[0041] In conjunction with the instruction manual Figure 5 , current sampling is realized by the Hall current sensor linear current sensor ACS712, which realizes the linear conversion of current-voltage through the Hall effect and has low power consumption. According to the data sheet of the linear current sensor ACS712 chip, the output voltage v of the current sensor linear current sensor ACS712 is obtained. 输出OUT With input current i in The relationship is:

[0042]

[0043] In conjunction with the instruction manual Figure 6 , the AC voltage regulator converts 220V rms The AC power is adjusted to 90-135Vrms as the input power of the prototype. The AC voltage regulator has a certain internal resistance, and the winding of the AC voltage regulator has a certain inductance under high frequency conditions. The bridgeless Boost PFC circuit works in discontinuous mode, and the current ripple is large; and there is no power frequency rectifier bridge between the Boost inductor and the AC source AC voltage regulator. The high-frequency ripple current flows directly through the AC voltage regulator and generates a voltage drop on the internal resistance. See the input voltage v in The waveform has large high-frequency ripples. When the input voltage increases or the load decreases, the input voltage v in The high-frequency ripples of the waveform become smaller.

[0044] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A single-stage resonant LED driving circuit for adjustable optical communication, comprising an LED driving circuit, characterized in that: The LED driving circuit includes a driving protection circuit, a voltage sampling circuit and a current sampling circuit. The voltage sampling circuit and the current sampling circuit are both connected to the driving protection circuit. The driving protection circuit includes a pulse signal input port PWMIN, an input and output port GPIO, a variable resistor R1, a resistor R2, a transistor T, an amplifier MC74VHG, a resistor R3, a resistor R4, an optocoupler HCPL3120, a power module QA02, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a diode D1 and a pulse signal output port PWM output OUT. The voltage sampling circuit and the current sampling circuit are both connected to the driving protection circuit. The driving protection circuit includes a pulse signal input port PWMIN, an input and output port GPIO, a variable resistor R1, a resistor R2, a transistor T, an amplifier MC74VHG, a resistor R3, a resistor R4, a photocoupler HCPL3120, a power module QA02, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a diode D1 and a pulse signal output port PWM output OUT. The circuit includes an input IN, a diode D1, a variable resistor R1, a resistor R2, a resistor R3, an input resistor Rin, a resistor R4, a resistor R5, a current sensor AMC1200, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a diode D2, a diode D3, an amplifier U2 and an output OUT. The current sampling circuit includes a linear current sensor ACS712, an LED, a feedback capacitor Cf, a variable resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a capacitor C1, a capacitor C2, a capacitor C3, a diode D1, a diode D2 and an operational amplifier LM358.

2. According to claim 1, a dimmable optical communication single-stage resonant LED driving circuit is characterized in that: The ENB end pin of the amplifier MC74VHG is connected to one end of the resistor R2, the IN end pin of the amplifier MC74VHG is respectively connected to one end of the resistor R3 and one end of the pulse signal input port PWMIN, the resistor R3 and the amplifier MC74VHG are respectively connected to the emitter and collector of the transistor T, the base of the transistor T is connected to one end of the variable resistor R1, the other end of the variable resistor R1 is connected to one end of the input and output port GPIO, the output OUT end pin of the amplifier MC74VHG is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the 2 end pin of the photoelectric coupler HCPL3120, the 7 end pin of the photoelectric coupler HCPL3120 is connected to one end of the resistor R5, the 6 end pin of the photoelectric coupler HCPL3120 is connected to one end of the resistor R6, and the other end of the resistor R5 is connected to one end of the diode D1.

3. The single-stage resonant LED driving circuit for adjustable optical communication according to claim 2, characterized in that: The other end of the diode D1 and the other end of the resistor R6 are both connected to one end of the pulse signal output port PWM output OUT, and the other end of the pulse signal output port PWM output OUT is respectively connected to one end of the resistor R7, one end of the capacitor C3, one end of the capacitor C4, one end of the resistor R8, one end of the capacitor C1, one end of the capacitor C2 and the 6th pin of the power module QA02, the other end of the resistor R7, the other end of the capacitor C3 and the other end of the capacitor C1 are all connected to the 7th pin of the power module QA02, the other end of the resistor R8, the other end of the capacitor C4 and the other end of the capacitor C2 are all connected to the 5th pin of the power module QA02, and the 2nd pin of the power module QA02, the 1st pin of the photoelectric coupler HCPL3120, the 3rd pin of the photoelectric coupler HCPL3120, the 4th pin of the photoelectric coupler HCPL3120, the emitter of the transistor T and the input end of the pulse signal input port PWMIN are all grounded.

4. The single-stage resonant LED driving circuit for adjustable optical communication according to claim 1, characterized in that: The pin 1 of the input IN is connected to one end of the input resistor Rin, the other end of the input resistor Rin is connected to one end of the variable resistor R1, the other end of the variable resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the pin 2 of the input IN, the variable resistor R1, the resistor R2 and one end of the diode D1 are connected, the connection between the resistor R3 and the input IN is connected to the other end of the diode D1, the connection between the resistor R2 and the resistor R3 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the pin 2 of the current sensor AMC1200.

5. The single-stage resonant LED driving circuit for adjustable optical communication according to claim 4, characterized in that: The 3-pin terminal of the current sensor AMC1200 is connected to one end of the resistor R5, the resistor R4 and the resistor R5 are connected in parallel with the capacitor C1, the 7-pin terminal of the current sensor AMC1200 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to one end of the resistor R7 and the 3-pin terminal of the amplifier U2, the 6-pin terminal of the current sensor AMC1200 is connected to one end of the resistor R8, the other end of the resistor R8 is respectively connected to the 2-pin terminal of the amplifier U2 and one end of the resistor R9, the other end of the resistor R9 and the 1-pin terminal of the amplifier U2 are both connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to one end of the capacitor C2 and the 1-pin terminal of the output OUT, the other end of the capacitor C2 is connected to one end of the diode D3, and the other end of the diode D3 is connected to one end of the diode D2.

6. The single-stage resonant LED driving circuit for adjustable optical communication according to claim 1, characterized in that: The IP+ terminal of the linear current sensor ACS712 is connected to one end of the LED, the output OUT terminal of the linear current sensor ACS712 is connected to one end of the resistor R4, the other end of the resistor R4 is respectively connected to one end of the resistor R5 and one end of the capacitor C1, the other end of the resistor R5 is connected to the positive electrode of the operational amplifier LM358, the connection point between the resistor R5 and the operational amplifier LM358 is connected to one end of the resistor R6, and the negative electrode of the operational amplifier LM358 is respectively connected to one end of the resistor R3 and one end of the resistor R7.

7. The single-stage resonant LED driving circuit for adjustable optical communication according to claim 6, characterized in that: The other end of the resistor R3 is connected to one end of the variable resistor R1 and one end of the resistor R2 respectively, the FILTER end of the linear current sensor ACS712 is connected to one end of the feedback capacitor Cf, the other end of the resistor R7 is connected in parallel with the capacitor C2, the surface of the operational amplifier LM358 is connected to one end of the resistor R8, and the other end of the resistor R8 is connected to one end of the capacitor C3, one end of the diode D1 and one end of the diode D2 respectively.

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